Publications by authors named "Daniele Marin"

151 Publications

Can procedure time for paracentesis be optimized based on bottle selection?

Abdom Radiol (NY) 2021 Mar 30. Epub 2021 Mar 30.

Department of Radiology, Duke University Medical Center, DUMC Box 3808, Durham, NC, 27710, USA.

Purpose: The purpose of our study was to assess if plastic containers could decrease the overall procedure time for paracentesis relative to more commonly used glass containers.

Methods: In this IRB exempt study, initial pilot data comparing filling time of glass and plastic containers in an ex vivo setting under identical conditions revealed power calculations that n = 37 patients per group would be needed to achieve standard deviation (SD) = 60 s, difference (diff) = 40 s, two-tailed alpha-level 0.05, and power 80%. Total of 43 patients (93 containers) were enrolled and randomized to glass or plastic bottles at enrollment. Timing of bottle filling was assessed using standardized sonographic screen captures.

Results: An interim look at statistics at n = 20 patients indicated that original conjectures from pilot data were conservative and smaller sample size was sufficient to stop the study and conduct the analyses. Specifically, SD = 54 s, diff = 49 s, two-tailed alpha-level 0.05, and power 80% required n = 21 patients per group. Plastic containers had a statistically significantly lower average filling time per bottle (162.7 ± 53.3 s) compared to glass (212.2 ± 50.4 s) (p = 0.003). Viscosity was calculated for each specimen and did not affect the statistical significance of the results (p = 0.32).

Conclusion: Plastic containers have 50 s time savings of per bottle filling time as compared to glass bottles as theorized based on their faster flow rate. This holds true in both an ex vivo setting and in patients and can have important downstream impacts on patient throughput, provider efficiency and system wide cost savings.
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http://dx.doi.org/10.1007/s00261-021-03033-8DOI Listing
March 2021

mutations are associated with favorable outcomes to immune checkpoint inhibitors across multiple cancer types.

J Immunother Cancer 2021 Mar;9(3)

Duke Cancer Institute Center for Prostate and Urologic Cancers, Durham, North Carolina, USA

Background: Low-density lipoprotein receptor-related protein 1b (encoded by ) is a putative tumor suppressor, and preliminary evidence suggests mutated cancers may have improved outcomes with immune checkpoint inhibitors (ICI).

Methods: We conducted a multicenter, retrospective pan-cancer analysis of patients with alterations treated with ICI at Duke University, Johns Hopkins University (JHU) and University of Michigan (UM). The primary objective was to assess the association between overall response rate (ORR) to ICI and pathogenic or likely pathogenic (P/LP) alterations compared with variants of unknown significance (VUS). Secondary outcomes were the associations with progression-free survival (PFS) and overall survival (OS) by status.

Results: We identified 101 patients (44 Duke, 35 JHU, 22 UM) with alterations who were treated with ICI. The most common tumor types by alteration (P/LP vs VUS%) were lung (36% vs 49%), prostate (9% vs 7%), sarcoma (5% vs 7%), melanoma (9% vs 0%) and breast cancer (3% vs 7%). The ORR for patients with P/LP versus VUS alterations was 54% and 13%, respectively (OR 7.5, 95% CI 2.9 to 22.3, p=0.0009). P/LP alterations were associated with longer PFS (HR 0.42, 95% CI 0.26 to 0.68, p=0.0003) and OS (HR 0.62, 95% CI 0.39 to 1.01, p=0.053). These results remained consistent when excluding patients harboring microsatellite instability (MSI) and controlling for tumor mutational burden (TMB).

Conclusions: This multicenter study shows significantly better outcomes with ICI therapy in patients harboring P/LP versus VUS alterations, independently of TMB/MSI status. Further mechanistic and prospective validation studies are warranted.
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http://dx.doi.org/10.1136/jitc-2020-001792DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7929846PMC
March 2021

"Bull's eye" appearance of hepatocellular adenomas in patients with glycogen storage disease type I - atypical magnetic resonance imaging findings: Two case reports.

World J Clin Cases 2021 Feb;9(4):871-877

Department of Radiology, Duke University Medical Center, Durham, NC 27710, United States.

Background: Hepatocellular adenomas are rare tumors that can occur in patients with glycogen storage disease type I.

Case Summary: We herein report two cases of histologically proven hepatocellular adenomas in patients with glycogen storage disease type I. Magnetic resonance imaging (MRI) was performed after bolus injection of gadoxetate disodium, a liver-specific gadolinium-based MRI contrast agent. In the present cases, some of the hepatocellular adenomas showed unexpectedly a "bull's eye" appearance on T2-weighted and post-contrast images, which was not previously described as imaging findings of hepatocellular adenomas in glycogen storage disease. A bull's eye appearance on T2-weighted images can be encountered in both benign (, abscess) or malignant (, epithelioid hemangioendothelioma, cholangio-carcinoma, and metastases) hepatic lesions.

Conclusion: We present two cases of hepatocellular adenomas in patients with glycogen storage disease type 1, in which gadoxetate disodium-MRI showed atypical imaging findings for hepatocellular adenomas. At present there is no systematic study evaluating MRI findings of hepatocellular adenomas in patients with glycogen storage disease, further studies are needed to specifically investigate this issue.
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http://dx.doi.org/10.12998/wjcc.v9.i4.871DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7852632PMC
February 2021

Clinical Implementation of Dual-Energy CT for Gastrointestinal Imaging.

AJR Am J Roentgenol 2020 Dec 30. Epub 2020 Dec 30.

Division of Abdominal Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA 02114, USA.

Dual-energy CT (DECT) overcomes several limitations of conventional single-energy CT (SECT) for the evaluation of gastrointestinal diseases. This article provides an overview of practical aspects of the DECT technology and acquisition protocols, reviews existing clinical applications, discusses current challenges, and describes future directions, with a focus on gastrointestinal imaging. A head-to-head comparison is provided of technical specifications among DECT scanner implementations. Energy- and material-specific DECT image reconstructions enable retrospective (i.e., after examination acquisition) image quality adjustments that are not possible using SECT systems. Such adjustments may, for example, correct insufficient contrast bolus or metal artifact, thereby potentially avoiding patient recalls. A combination of low keV monochromatic images, iodine maps, and virtual unenhanced images can be included in protocols to improve lesion detection and disease characterization. Relevant literature is reviewed regarding use of DECT for evaluation of the liver, gallbladder, pancreas, and bowel. Challenges involving cost, workflow, body habitus, and variability in DECT measurements are considered. Incorporation of artificial intelligence and machine-learning image reconstruction algorithms, PACS integration, photon-counting hardware, and novel contrast agents are expected to expand the multi-energy capability of DECT and further augment its value.
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http://dx.doi.org/10.2214/AJR.20.25093DOI Listing
December 2020

Split-Bolus, Single-Acquisition, Dual-Phase Abdominopelvic CT Angiography for the Evaluation of Lung Transplant Candidates: Image Quality and Resource Utilization.

AJR Am J Roentgenol 2020 12 14;215(6):1520-1527. Epub 2020 Oct 14.

Department of Radiology, Duke University, Box 3808 DUMC, Durham, NC 27710.

The purpose of this study was to assess the image quality and resource utilization of single-injection, split-bolus, dual-enhancement abdominopelvic CT angiography (hereafter referred to as dual-enhancement CTA) performed for combined vascular and solid organ assessment compared with those of single-injection, single-enhancement abdominopelvic CT angiography (hereafter referred to as single-enhancement CTA) for vascular assessment in combination with additional examinations (CT, MRI, and US) performed to assess for malignancy in lung transplant candidates. We retrospectively reviewed 100 patients who underwent abdominopelvic CTA examinations before lung transplant. Cohort A ( = 50) underwent dual-enhancement CTA and cohort B ( = 50) underwent single-enhancement CTA. Contrast opacification of the vasculature was assessed along the abdominal aorta through the right femoral artery. Solid organ enhancement was assessed in the right lobe of the liver and the right renal cortex. Measurements of mean radiation dose, contrast exposure, and cost of the studies (in U.S. dollars) were compared. Mean (± SD) vascular enhancement on dual-enhancement CTA and single-enhancement CTA was 334.2 ± 26.5 HU (coefficient of variation, 8.3%) and 340.0 ± 21.6 HU (coefficient of variation, 6.5%) ( 0.23), respectively. For dual-enhancement CTA and single-enhancement CTA, mean liver enhancement was 125.8 ± 30.5 HU and 60.4 ± 6.9 HU ( 0.01), respectively, whereas mean renal cortical enhancement was 260.3 ± 62.2 HU and 133.4 ± 38.6 HU ( 0.01), respectively. The mean IV contrast volume was 150 mL for dual-enhancement CTA and 75 mL for single-enhancement CTA. Cohort A underwent six additional imaging studies (one of which was a CT colonography study with an effective dose of 19.0 mSv) at a total cost of $9840 per patient. Cohort B underwent 44 additional imaging studies (mean effective dose, 12.7 ± 6.5 mSv) at a total cost of $12,846 per patient (resulting in a 30.6% reduction in cost for dual-enhancement CTA studies; 0.0001). Dual-enhancement abdominopelvic CTA allows combined vascular and abdominopelvic solid organ assessment with improved image quality and a lower cost compared with traditional imaging pathways.
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http://dx.doi.org/10.2214/AJR.19.22335DOI Listing
December 2020

How frequently does hepatocellular carcinoma develop in at-risk patients with a negative liver MRI examination with intravenous Gadobenate dimeglumine?

Abdom Radiol (NY) 2021 03 19;46(3):969-978. Epub 2020 Sep 19.

Department of Radiology, Duke University Medical Center, Box 3808, Durham, NC, 27710, USA.

Objective: To determine the rate of development of clinically significant liver nodules (LR-4, LR-5, LR-M) after a negative MRI in an HCC screening population.

Methods: This retrospective study included patients at risk of developing HCC requiring imaging surveillance who had undergone multiphase Gadobenate dimeglumine-enhanced MRI that was negative and had follow up LI-RADS compliant multiphase CTs or MRIs for at least 12 months or positive follow-up within 12 months. Follow-up examinations were classified as negative (no nodules or only LR-1 nodules) or positive (nodule other than LR-1). Time-to-first positive examination, types of nodules, and cumulative incidence of nodule development were recorded.

Results: 204 patients (mean age 58.9 ± 10.2 years, 128 women), including 172 with cirrhosis, were included. Based CT/MRI follow-up (median 35 months, range 12-80 months), the overall cumulative incidence of developing a nodule was 10.5%. Cumulative incidence of nodule development was: 0.5% at 6-9 months and 2.1% at 12 ± 3 months, including one LR-4 nodule, one LR-M nodule, and two LR-3 nodules. The cumulative incidence of clinically significant nodule development was 1.1% at 9-15 months. 70% (143/204) of patients also underwent at least one US follow-up, and no patient developed a positive US examination following index negative MRI.

Conclusion: Clinically significant liver nodules develop in 1.1% of at-risk patients in the first year following negative MRI. While ongoing surveillance is necessary for at-risk patients, our study suggests than longer surveillance intervals after a negative MRI may be reasonable and that further research is needed to explore this possibility.
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http://dx.doi.org/10.1007/s00261-020-02771-5DOI Listing
March 2021

Impact of dual energy cardiac CT for metal artefact reduction post aortic valve replacement.

Eur J Radiol 2020 Aug 17;129:109135. Epub 2020 Jun 17.

Department of Radiology, Duke University Medical Center, Durham, NC 27705, United States.

Purpose: Assess image quality of dual-energy (DE) and single-energy (SE) cardiac multi-detector computed tomographic (MDCT) post aortic valve replacement (AVR) on a dual source MDCT scanner.

Methods: Eighty patients with cardiac MDCT acquisitions (ECG gated, dual-source) post-surgical and transcatheter AVR were retrospectively identified. Forty DE (cohort 1) and 40 SE acquisitions (cohort 2; 100 or 120 kVp) were reviewed. Metal artefact at valve coaptation (VC) and valve insertion site (VIS), and contrast enhancement were assessed. Valve leaflet edge definition was graded on a 4-point scale by three radiologists.

Results: The mean percentage valve area obscured by metal artifact differed between the cohorts; cohort 1 DE blended, high keV and low keV: 14.8 %, 11.1 % and 17.8 % at VC and 16.4 %, 13 %, 20.4 % at VIS respectively. Cohort 2: 25.8 % and 33.6 % (VC and VIS); each DE reconstruction vs SE: P < 0.0001. Average contrast opacification and coefficient of variance for cohort 1: 562.9 ± 144.7, 281.1 ± 60.3 and 1132.7 ± 300.8 Hounsfield Units (HU) and 9.6 %, 10 % and 8.9 %. For cohort 2: 437.2 ± 119.2 HU and 10.8 % (P < 0.01). Average leaflet edge definition cohort 1: 2.3 ± 0.4, 2.7 ± 0.2 and 2.3 ± 0.2, and cohort 2: 2.9 ± 0.2.

Conclusion: DE high keV renderings can result in up to 17.2 % less metal artefact compared to standard SE acquisition for cardiac CT. Contrast opacification and homogeneity is higher for DE blended and low keV renderings compared to SE acquisition with leaflet visibility preferred for low keV and blended DE renderings.
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http://dx.doi.org/10.1016/j.ejrad.2020.109135DOI Listing
August 2020

Deep learning based spectral extrapolation for dual-source, dual-energy x-ray computed tomography.

Med Phys 2020 Sep 6;47(9):4150-4163. Epub 2020 Jul 6.

Department of Radiology, Center for In Vivo Microscopy, Duke University, Durham, NC, 27710, USA.

Purpose: Data completion is commonly employed in dual-source, dual-energy computed tomography (CT) when physical or hardware constraints limit the field of view (FoV) covered by one of two imaging chains. Practically, dual-energy data completion is accomplished by estimating missing projection data based on the imaging chain with the full FoV and then by appropriately truncating the analytical reconstruction of the data with the smaller FoV. While this approach works well in many clinical applications, there are applications which would benefit from spectral contrast estimates over the larger FoV (spectral extrapolation)-e.g. model-based iterative reconstruction, contrast-enhanced abdominal imaging of large patients, interior tomography, and combined temporal and spectral imaging.

Methods: To document the fidelity of spectral extrapolation and to prototype a deep learning algorithm to perform it, we assembled a data set of 50 dual-source, dual-energy abdominal x-ray CT scans (acquired at Duke University Medical Center with 5 Siemens Flash scanners; chain A: 50 cm FoV, 100 kV; chain B: 33 cm FoV, 140 kV + Sn; helical pitch: 0.8). Data sets were reconstructed using ReconCT (v14.1, Siemens Healthineers): 768 × 768 pixels per slice, 50 cm FoV, 0.75 mm slice thickness, "Dual-Energy - WFBP" reconstruction mode with dual-source data completion. A hybrid architecture consisting of a learned piecewise linear transfer function (PLTF) and a convolutional neural network (CNN) was trained using 40 scans (five scans reserved for validation, five for testing). The PLTF learned to map chain A spectral contrast to chain B spectral contrast voxel-wise, performing an image domain analog of dual-source data completion with approximate spectral reweighting. The CNN with its U-net structure then learned to improve the accuracy of chain B contrast estimates by copying chain A structural information, by encoding prior chain A, chain B contrast relationships, and by generalizing feature-contrast associations. Training was supervised, using data from within the 33-cm chain B FoV to optimize and assess network performance.

Results: Extrapolation performance on the testing data confirmed our network's robustness and ability to generalize to unseen data from different patients, yielding maximum extrapolation errors of 26 HU following the PLTF and 7.5 HU following the CNN (averaged per target organ). Degradation of network performance when applied to a geometrically simple phantom confirmed our method's reliance on feature-contrast relationships in correctly inferring spectral contrast. Integrating our image domain spectral extrapolation network into a standard dual-source, dual-energy processing pipeline for Siemens Flash scanner data yielded spectral CT data with adequate fidelity for the generation of both 50 keV monochromatic images and material decomposition images over a 30-cm FoV for chain B when only 20 cm of chain B data were available for spectral extrapolation.

Conclusions: Even with a moderate amount of training data, deep learning methods are capable of robustly inferring spectral contrast from feature-contrast relationships in spectral CT data, leading to spectral extrapolation performance well beyond what may be expected at face value. Future work reconciling spectral extrapolation results with original projection data is expected to further improve results in outlying and pathological cases.
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http://dx.doi.org/10.1002/mp.14324DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7722037PMC
September 2020

Variability of quantitative measurements of metastatic liver lesions: a multi-radiation-dose-level and multi-reader comparison.

Abdom Radiol (NY) 2021 01 10;46(1):226-236. Epub 2020 Jun 10.

Department of Radiology, Duke University Medical Center, 2301 Erwin Rd, Durham, NC, 27710, USA.

Purpose: To evaluate the variability of quantitative measurements of metastatic liver lesions by using a multi-radiation-dose-level and multi-reader comparison.

Methods: Twenty-three study subjects (mean age, 60 years) with 39 liver lesions who underwent a single-energy dual-source contrast-enhanced staging CT between June 2015 and December 2015 were included. CT data were reconstructed with seven different radiation dose levels (ranging from 25 to 100%) on the basis of a single CT acquisition. Four radiologists independently performed manual tumor measurements and two radiologists performed semi-automated tumor measurements. Interobserver, intraobserver, and interdose sources of variability for longest diameter and volumetric measurements were estimated and compared using Wilcoxon rank-sum tests and intraclass correlation coefficients.

Results: Inter- and intraobserver variabilities for manual measurements of the longest diameter were higher compared to semi-automated measurements (p < 0.001 for overall). Inter- and intraobserver variabilities of volume measurements were higher compared to the longest diameter measurement (p < 0.001 for overall). Quantitative measurements were statistically different at < 50% radiation dose levels for semi-automated measurements of the longest diameter, and at 25% radiation dose level for volumetric measurements. The variability related to radiation dose was not significantly different from the inter- and intraobserver variability for the measurements of the longest diameter.

Conclusion: The variability related to radiation dose is comparable to the inter- and intraobserver variability for measurements of the longest diameter. Caution should be warranted in reducing radiation dose level below 50% of a conventional CT protocol due to the potentially detrimental impact on the assessment of lesion response in the liver.
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http://dx.doi.org/10.1007/s00261-020-02601-8DOI Listing
January 2021

Noise and spatial resolution properties of a commercially available deep learning-based CT reconstruction algorithm.

Med Phys 2020 Sep 6;47(9):3961-3971. Epub 2020 Jul 6.

Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, 2424 Erwin Road, Suite 302, Durham, NC, 27705, USA.

Purpose: To characterize the noise and spatial resolution properties of a commercially available deep learning-based computed tomography (CT) reconstruction algorithm.

Methods: Two phantom experiments were performed. The first used a multisized image quality phantom (Mercury v3.0, Duke University) imaged at five radiation dose levels (CTDI : 0.9, 1.2, 3.6, 7.0, and 22.3 mGy) with a fixed tube current technique on a commercial CT scanner (GE Revolution CT). Images were reconstructed with conventional (FBP), iterative (GE ASiR-V), and deep learning-based (GE True Fidelity) reconstruction algorithms. Noise power spectrum (NPS), high-contrast (air-polyethylene interface), and intermediate-contrast (water-polyethylene interface) task transfer functions (TTF) were measured for each dose level and phantom size and summarized in terms of average noise frequency (f ) and frequency at which the TTF was reduced to 50% (f ), respectively. The second experiment used a custom phantom with low-contrast rods and lung texture sections for the assessment of low-contrast TTF and noise spatial distribution. The phantom was imaged at five dose levels (CTDI : 1.0, 2.1, 3.0, 6.0, and 10.0 mGy) with 20 repeated scans at each dose, and images reconstructed with the same reconstruction algorithms. The local noise stationarity was assessed by generating spatial noise maps from the ensemble of repeated images and computing a noise inhomogeneity index, , following AAPM TG233 methods. All measurements were compared among the algorithms.

Results: Compared to FBP, noise magnitude was reduced on average (± one standard deviation) by 74 ± 6% and 68 ± 4% for ASiR-V (at "100%" setting) and True Fidelity (at "High" setting), respectively. The noise texture from ASiR-V had substantially lower noise frequency content with 55 ± 4% lower NPS f compared to FBP while True Fidelity had only marginally different noise frequency content with 9 ± 5% lower NPS f compared to FBP. Both ASiR-V and True Fidelity demonstrated locally nonstationary noise in a lung texture background at all radiation dose levels, with higher noise near high-contrast edges of vessels and lower noise in uniform regions. At the 1.0 mGy dose level values were 314% and 271% higher in ASiR-V and True Fidelity compared to FBP, respectively. High-contrast spatial resolution was similar between all algorithms for all dose levels and phantom sizes (<3% difference in TTF f ). Compared to FBP, low-contrast spatial resolution was lower for ASiR-V and True Fidelity with a reduction of TTF f of up to 42% and 36%, respectively.

Conclusions: The deep learning-based CT reconstruction demonstrated a strong noise magnitude reduction compared to FBP while maintaining similar noise texture and high-contrast spatial resolution. However, the algorithm resulted in images with a locally nonstationary noise in lung textured backgrounds and had somewhat degraded low-contrast spatial resolution similar to what has been observed in currently available iterative reconstruction techniques.
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http://dx.doi.org/10.1002/mp.14319DOI Listing
September 2020

Hepatobiliary phase hypointensity predicts progression to hepatocellular carcinoma for intermediate-high risk observations, but not time to progression.

Eur J Radiol 2020 Jul 23;128:109018. Epub 2020 Apr 23.

Department of Radiology, Duke University Medical Center, Durham, NC, United States. Electronic address:

Purpose: To determine whether hepatobiliary phase hypointensity, enhancing "capsule" and size provide prognostic information regarding the risk of progression to hepatocellular carcinoma (HCC), as well as the time to progression, of intermediate to high risk observations ≥ 10 mm with arterial phase hyperenhancement (APHE).

Method: This retrospective dual-institution study included 160 LR-3 and 26 LR-4 observations measuring more than 10 mm and having APHE in 136 patients (mean age [SD], 57 [11] years old). A composite reference standard of pathologic analysis and imaging follow-up was used. The prognostic performance of hepatobiliary phase hypointensity, enhancing "capsule" and size (cut-off: 20 mm) for the prediction of probability of progression to HCC and median time to progression to HCC was assessed and compared by means of Log-rank test, Cox-regression and Kaplan-Meier curves.

Results: 110 (59%) of 186 of observations progressed to HCC, 29.1% (32) progressed within 6 months, 60% (66) within 1 year and 84.5% (93) within 2 years. Hepatobiliary phase hypointensity was a significant predictor of progression to HCC (p < 0.0001, odds ratio: 20.62) but not of time to progression (p = 0.17). Median time to progression to HCC was 284 days [IQR: 266-363] and was shorter - though not significantly - for observations with enhancing "capsule" (118 days vs 301 days; p = 0.19).

Conclusions: Hepatobiliary phase hypointensity is an independent predictor of progression to HCC in intermediate to high risk APHE observations ≥ 10 mm.
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http://dx.doi.org/10.1016/j.ejrad.2020.109018DOI Listing
July 2020

ACR Appropriateness Criteria® Crohn Disease.

J Am Coll Radiol 2020 May;17(5S):S81-S99

Specialty Chair, Virginia Commonwealth University Medical Center, Richmond, Virginia.

Three common clinical scenarios involving use of imaging in Crohn disease are covered. These include the initial evaluation of Crohn disease when the diagnosis has not been previously established, the evaluation for anticipated exacerbation of known disease, and the evaluation of disease activity during therapy monitoring. The appropriateness of a given imaging modality for each scenario is rated as one of three categories (usually appropriate, may be appropriate, usually not appropriate) to help guide evaluation. Pediatric presentation of Crohn disease and the appropriateness of imaging are not covered in this document. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.
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http://dx.doi.org/10.1016/j.jacr.2020.01.030DOI Listing
May 2020

ACR Appropriateness Criteria® Suspected Small-Bowel Obstruction.

J Am Coll Radiol 2020 May;17(5S):S305-S314

Specialty Chair, Virginia Commonwealth University Medical Center, Richmond, Virginia.

Small-bowel obstruction is a common cause of abdominal pain and accounts for a significant proportion of hospital admissions. Radiologic imaging plays the key role in the diagnosis and management of small-bowel obstruction as neither patient presentation, the clinical examination, nor laboratory testing are sufficiently sensitive or specific enough to diagnose or guide management. This document focuses on the imaging evaluation of the two most commonly encountered clinical scenarios related to small-bowel obstruction: the acute presentation and the more indolent, low-grade, or intermittent presentation. This document hopes to clarify the appropriate utilization of the many imaging procedures that are available and commonly employed in these clinical settings. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.
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http://dx.doi.org/10.1016/j.jacr.2020.01.025DOI Listing
May 2020

Liver Imaging Reporting and Data System (LI-RADS) v2018: diagnostic value of ancillary features favoring malignancy in hypervascular observations ≥ 10 mm at intermediate (LR-3) and high probability (LR-4) for hepatocellular carcinoma.

Eur Radiol 2020 Jul 27;30(7):3770-3781. Epub 2020 Feb 27.

Department of Radiology, University of Pittsburgh School of Medicine, 200 Lothrop Street, Pittsburgh, PA, 15213, USA.

Objective: This study was conducted in order to assess the diagnostic accuracy of LI-RADS v2018 ancillary features (AFs) favoring malignancy applied to LR-3 and LR-4 observations on gadoxetate-enhanced MRI.

Methods: In this retrospective dual-institution study, we included consecutive patients at high risk for hepatocellular carcinoma (HCC) imaged with gadoxetate disodium-enhanced MRI between 2009 and 2014 fulfilling the following criteria: (i) at least one LR-3 or LR-4 observation ≥ 10 mm; (ii) nonrim arterial phase hyperenhancement; and (iii) confirmation of benignity or malignancy by pathology or imaging follow-up. We compared the distribution of AFs between HCCs and benign observations and the diagnostic performance for the diagnosis of HCC using univariate and multivariate analyses. Significance was set at p value < 0.05.

Results: Two hundred five observations were selected in 155 patients (108 M, 47 F) including 167 (81.5%) LR-3 and 38 (18.5%) LR-4. There were 126 (61.5%) HCCs and 79 (28.5%) benign lesions. A significantly larger number of AFs favoring malignancy were found in LR-3 and LR-4 lesions that progressed to HCC compared to benign lesions (p < 0.001 and p = 0.003, respectively). The most common AFs favoring malignancy in HCCs were hepatobiliary phase (HBP) hypointensity (p < 0.001), transitional phase hypointensity (p < 0.001), and mild-moderate T2 hyperintensity (p < 0.001). Sensitivity and specificity of AFs for the diagnosis of HCC ranged 0.8-76.2% and 86.1-100%, respectively. HBP hypointensity yielded the highest sensitivity but also the lowest specificity and was the only AF remaining independently associated with the diagnosis of HCC at multivariate logistic regression analysis (OR 14.83, 95% CI 5.81-42.76, p < 0.001).

Conclusions: Among all AFs, HBP hypointensity yields the highest sensitivity for the diagnosis of HCC.

Key Points: • LR-3 and LR-4 observations diagnosed as HCC have a significantly higher number of ancillary features favoring malignancy compared to observations proven to be benign. • The presence of three or more ancillary features favoring malignancy has a high specificity (96.2%) for the diagnosis of HCC. • Among all ancillary features favoring malignancy, hepatobiliary phase hypointensity yields the highest sensitivity, but also the lowest specificity for the diagnosis of HCC.
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http://dx.doi.org/10.1007/s00330-020-06698-9DOI Listing
July 2020

Ultrasound-guided non-targeted liver core biopsy: comparison of the efficacy of two different core needle biopsy systems using an ex-vivo animal model and retrospective review of clinical experience.

Clin Imaging 2020 May 9;61:36-42. Epub 2020 Jan 9.

Department of Radiology, Duke University Medical Center, 2301 Erwin Road, Box 3808, Durham, NC 22710, United States of America. Electronic address:

Purpose: To compare the efficacy of two 18-gauge core needle biopsy systems, the Achieve® (Merit Medical) and the Marquee® (BD Bard), using an ex-vivo animal liver model and retrospective review of clinical experience.

Methods: Sixty ex-vivo liver biopsy samples were obtained using the Achieve® (n = 30) and the Marquee® (n = 30) needles. In addition, 20 liver biopsy samples from 20 patients obtained using the Achieve® (n = 10) and Marquee® (n = 10) were compared retrospectively. One pathologist, blinded to needle type, recorded total core length and the number of complete portal triads. Ex vivo measurements were compared using mixed effects linear, logistic, and ordinal regression. In vivo measurements were compared using Student's t-test.

Results: For the Achieve® and Marquee® needles, the mean(SD) total core length (mm) of ex vivo samples was 11.0(3.3) and 12.6(3.4), respectively (P = 0.069) and the adequacy rate was 23.3% and 50%, respectively (P = 0.04). Mean number of portal triads of ex vivo samples was 7.2(2.9) and 8.6(3.8), respectively (P = 0.13), and the adequacy rate was 73.3% and 83.3%, respectively (P = 0.32). For in vivo samples, the Achieve® and Marquee® needles demonstrates mean(SD) total core length (mm) of 24.6(7.1) and 32.0(4.6), respectively (P = 0.01), adequacy rate (P = 0.06). Mean number of portal triads was 14.9(4.8) and 19.6(4.1), respectively (P = 0.03), adequacy rate (P = 0.47).

Conclusions: Slightly longer core biopsies were obtained with the Marquee® needle compared with the Achieve® needle. Early clinical experience demonstrates no significant difference in sample adequacy rates. Both needle types can be expected to provide adequate samples for pathologic assessment of liver tissue.
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http://dx.doi.org/10.1016/j.clinimag.2020.01.005DOI Listing
May 2020

CT and MR imaging evaluation of living liver donors.

Abdom Radiol (NY) 2021 01;46(1):17-28

Department of Radiology, Duke University Medical Center, Durham, NC, 27710, USA.

Preoperative cross-sectional imaging evaluation of potential living liver donors allows to exclude donors with an increased risk for morbidity and mortality, and to assure that a suitable graft for the recipient can be obtained, minimizing the risk of complications in both the donor and the recipient. CT is routinely performed to delineate the anatomy of the liver, relevant vasculature, and liver volumes in whole right or left lateral segment donation. MR imaging is the gold standard for the assessment of biliary anatomy and allows a better quantification of hepatic steatosis compared to CT. Knowledge of normal and variant vascular and biliary anatomy and their surgical relevance for liver transplantation is of paramount importance for the radiologist. The purpose of this review is to outline the current role of CT and MR imaging in the assessment of hepatic parenchyma, hepatic vascular anatomy, biliary anatomy, and hepatic volumetry in the potential living liver donor with short notes on acquisition protocols and the relevant reportable findings.
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http://dx.doi.org/10.1007/s00261-019-02385-6DOI Listing
January 2021

Cost-effectiveness of dual-energy CT versus multiphasic single-energy CT and MRI for characterization of incidental indeterminate renal lesions.

Abdom Radiol (NY) 2020 06;45(6):1896-1906

Department of Radiology, Harvard Medical School, Massachusetts General Hospital, 55 Fruit Street, White 270, Boston, MA, 02114, USA.

Purpose: To evaluate the cost-effectiveness of DECT versus multiphasic CT and MRI for characterizing small incidentally detected indeterminate renal lesions using a Markov Monte Carlo decision-analytic model.

Background: Incidental renal lesions are commonly encountered due to the increasing utilization of medical imaging and the increasing prevalence of renal lesions with age. Currently recommended imaging modalities to further characterize incidental indeterminate renal lesions have some inherent drawbacks. Single-phase DECT may overcome these limitations, but its cost-effectiveness remains uncertain.

Materials And Methods: A decision-analytic (Markov) model was constructed to estimate life expectancy and lifetime costs for otherwise healthy 64-year-old patients with small (≤ 4 cm) incidentally detected, indeterminate renal lesions on routine imaging (e.g., ultrasound or single-phase CT). Three strategies for evaluating renal lesions for enhancement were compared: multiphase SECT (e.g., true unenhanced and nephrographic phase), multiphasic MRI, and single-phase DECT (nephrographic phase in dual-energy mode). The model incorporated modality-specific diagnostic test performance, incidence, and prevalence of incidental renal cell carcinomas (RCCs), effectiveness, costs, and health outcomes. An incremental cost-effectiveness analysis was performed to identify strategy preference at willingness-to-pay (WTP) thresholds of $50,000 and $100,000 per quality-adjusted life-year (QALY) gained. Deterministic and probabilistic sensitivity analysis were performed.

Results: In the base case analysis, expected mean costs per patient undergoing characterization of incidental renal lesions were $2567 for single-phase DECT, $3290 for multiphasic CT, and $3751 for multiphasic MRI. Associated quality-adjusted life-years were the highest for single-phase DECT at 0.962, for multiphasic MRI it was 0.940, and was the lowest for multiphasic CT at 0.925. Because of lower associated costs and higher effectiveness, the single-phase DECT strategy dominated the other two strategies.

Conclusions: Single-phase DECT is potentially more cost-effective than multiphasic SECT and MRI for evaluating small incidentally detected indeterminate renal lesions.
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http://dx.doi.org/10.1007/s00261-019-02380-xDOI Listing
June 2020

ACR Appropriateness Criteria® Palpable Abdominal Mass-Suspected Neoplasm.

J Am Coll Radiol 2019 Nov;16(11S):S384-S391

Specialty Chair, Virginia Commonwealth University Medical Center, Richmond, Virginia.

Palpable abdominal masses may arise from the abdominal cavity or the abdominal wall. The differential diagnosis is broad for each variant ranging from benign lipomas, inflammatory processes, to malignant tumors. The imaging approach to diagnosis varies by location. For intra-abdominal masses, contrast-enhanced CT and ultrasound examination have demonstrated accuracy. For abdominal wall masses, which may arise from muscle, subcutaneous tissue, or connective tissue, MRI, CT, and ultrasound all provide diagnostic value. This publication reviews the current evidence supporting the imaging approach to diagnosis of palpable abdominal masses for two variants: suspected intra-abdominal neoplasm and suspected abdominal wall masses. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.
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http://dx.doi.org/10.1016/j.jacr.2019.05.014DOI Listing
November 2019

Local Tumor Control and Patient Outcome Using Stereotactic Body Radiation Therapy for Hepatocellular Carcinoma: iRECIST as a Potential Substitute for Traditional Criteria.

AJR Am J Roentgenol 2019 12 15;213(6):1232-1239. Epub 2019 Oct 15.

Department of Radiology, Duke University Medical Center, 2301 Erwin Rd, Durham, NC 27710.

The purpose of this study was to investigate whether, compared with traditional criteria, the modified Response Evaluation Criteria in Solid Tumors version 1.1 for immune-based therapeutics (iRECIST) improves prediction of local tumor control and survival in patients with hepatocellular carcinoma (HCC) treated with stereotactic body radiotherapy (SBRT). Fifty-one HCC lesions (mean size, 3.1 cm) treated with SBRT in 41 patients (mean age, 67 years) were retrospectively included. Each patient underwent CT or MRI before SBRT and at least once after SBRT. Best overall response was categorized using Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1), iRECIST, World Health Organization (WHO) criteria, modified Response Evaluation Criteria in Solid Tumors (mRECIST), and European Association for the Study of the Liver (EASL) criteria. Lesions were then classified as local tumor control (i.e., stable disease, partial response, or complete response) or local treatment failure (i.e., progressive disease) by each tumor response criteria. Proportions of local tumor control were compared using the McNemar exact test. The 1-year overall survival was estimated using the Kaplan-Meier method. The median follow-up after SBRT was 21.0 months. The local tumor control rate was 94.1% (48/51) by iRECIST, 88.2% (45/51) by RECIST 1.1, 72.5% (37/51) by WHO criteria, 80.4% (41/51) by mRECIST, and 72.5% (37/51) by EASL criteria. The local tumor control rate was significantly higher according to iRECIST compared with WHO ( = 0.0010) and EASL ( = 0.0225) criteria. The 1-year survival rate for patients with local tumor control according to iRECIST (86.4%) was higher (although not statistically significant) compared with the 1-year survival rate for patients with local tumor control according to the other response criteria. iRECIST may provide more robust interpretation of HCC response after SBRT, yielding improved prediction of local tumor control and 1-year survival rates compared with traditional criteria.
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http://dx.doi.org/10.2214/AJR.18.20842DOI Listing
December 2019

Evaluation of Intraindividual Contrast Enhancement Variability for Determining the Maximum Achievable Consistency in CT.

AJR Am J Roentgenol 2020 01 1;214(1):18-23. Epub 2019 Oct 1.

Department of Radiology, Duke University Medical Center, 2301 Erwin Rd, Durham, NC 27710.

The purpose of this study was to quantify temporal variability in vascular and parenchymal enhancement within the same patient and to determine technique-related factors contributing to this variability. We identified 100 patients who underwent four CT scans within 12 months with identical acquisition and contrast injection parameters. Enhancement was recorded in the abdominal aorta, main portal vein, liver parenchyma, and subcutaneous fat. Patient demographic and body habitus data were recorded. Injection-related factors were recorded including delay time from contrast injection to image acquisition. All pairwise differences in enhancement within each patient were evaluated for absolute and percentage change. Based on predetermined thresholds, we observed clinically relevant variability in 34% of patients for the abdominal aorta, 38% for the portal vein, and 33% for the liver parenchyma. A highly significant association was observed between higher variability in delay time and variability in the abdominal aorta ( = 0.009) and between female sex and variability in liver parenchyma ( = 0.008). A marginally significant association was seen between increasing age ( = 0.025) and female sex ( = 0.039) with variability in the abdominal aorta. No statistically significant association was found between all recorded variables and variability in the portal vein. Approximately one-third of patients may show clinically relevant variability in enhancement of the abdominal aorta, portal vein, and liver parenchyma even when using identical scanning and injection parameters. Delay time was the only controllable factor associated with variability in enhancement of the abdominal aorta; no other controllable factor is associated with variability in the portal vein or liver parenchyma.
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http://dx.doi.org/10.2214/AJR.19.21628DOI Listing
January 2020

Reproducibility of CT Radiomic Features within the Same Patient: Influence of Radiation Dose and CT Reconstruction Settings.

Radiology 2019 12 1;293(3):583-591. Epub 2019 Oct 1.

From the Department of Radiology (M.M., J.R., F.V., R.C.N., D.M.) and Duke Advanced Imaging Laboratories (J.S., E.S.), Duke University Medical Center, 2301 Erwin Rd, Durham, NC 27710; Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim-Heidelberg University, Mannheim, Germany (M.M.); Section of Department of Radiology, DIBIMED, University of Palermo, Palermo, Italy (F.V.); Siemens Healthineers, Malvern, Pa (J.C.R.); and Department of Radiology, Stanford University, School of Medicine, Stanford, Calif (B.N.P.).

Background Results of recent phantom studies show that variation in CT acquisition parameters and reconstruction techniques may make radiomic features largely nonreproduceable and of limited use for prognostic clinical studies. Purpose To investigate the effect of CT radiation dose and reconstruction settings on the reproducibility of radiomic features, as well as to identify correction factors for mitigating these sources of variability. Materials and Methods This was a secondary analysis of a prospective study of metastatic liver lesions in patients who underwent staging with single-energy dual-source contrast material-enhanced staging CT between September 2011 and April 2012. Technique parameters were altered, resulting in 28 CT data sets per patient that included different dose levels, section thicknesses, kernels, and reconstruction algorithm settings. By using a training data set ( = 76), reproducible intensity, shape, and texture radiomic features (reproducibility threshold, ≥ 0.95) were selected and correction factors were calculated by using a linear model to convert each radiomic feature to its estimated value in a reference technique. By using a test data set ( = 75), the reproducibility of hierarchical clustering based on 106 radiomic features measured with different CT techniques was assessed. Results Data in 78 patients (mean age, 60 years ± 10; 33 women) with 151 liver lesions were included. The percentage of radiomic features deemed reproducible for any variation of the different technical parameters was 11% (12 of 106). Of all technical parameters, reconstructed section thickness had the largest impact on the reproducibility of radiomic features (12.3% [13 of 106]) if only one technical parameter was changed while all other technical parameters were kept constant. The results of the hierarchical cluster analysis showed improved clustering reproducibility when reproducible radiomic features with dedicated correction factors were used (ρ = 0.39-0.71 vs ρ = 0.14-0.47). Conclusion Most radiomic features are highly affected by CT acquisition and reconstruction settings, to the point of being nonreproducible. Selecting reproducible radiomic features along with study-specific correction factors offers improved clustering reproducibility. © RSNA, 2019 See also the editorial by Sosna in this issue.
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http://dx.doi.org/10.1148/radiol.2019190928DOI Listing
December 2019

A Simulation Paradigm for Evaluation of Subtle Liver Lesions at Pediatric CT: Performance and Confidence.

Radiol Imaging Cancer 2019 Sep 27;1(1):e190027. Epub 2019 Sep 27.

Department of Radiology (J.S.N., L.N., B.C.A., J.T.D., A.D., R.G., D.M., C.M.M., V.P., G.R.S.), Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Medical Physics Graduate Program (J.B.S., E.S., T.R.), and Departments of Biomedical Engineering, Electrical and Computer Engineering, and Physics (E.S.), Duke University Medical Center, Box 3808, Durham, NC 27710; Department of Biostatistics and Bioinformatics, Duke University School of Medicine, Durham, NC (A.E., B.Z.); and Department of Radiology, Stanford University School of Medicine, Stanford, Calif (B.N.P., D.P.F.).

Purpose: To create and validate a systematic observer performance platform for evaluation of simulated liver lesions at pediatric CT and to test this paradigm to measure the effect of radiation dose reduction on detection performance and reader confidence.

Materials And Methods: Thirty normal pediatric (from patients aged 0-10 years) contrast material-enhanced, de-identified abdominal CT scans obtained from July 1, 2012, through July 1, 2016, were retrospectively collected from the clinical database. The study was exempt from institutional review board approval. Zero to three simulated, low-contrast liver lesions (≤6 mm) were digitally inserted by using software, and noise was added to simulate reductions in volume CT dose index (representing radiation dose estimation) of 25% and 50%. Pediatric, abdominal, and resident radiologists (three of each) reviewed 90 data sets in three sessions using an online interface, marking each lesion location and rating confidence (scale, 0-100). Statistical analysis was performed by using software.

Results: Mixed-effects models revealed a significant decrease in detection sensitivity as radiation dose decreased ( < .001). The mean confidence of the full-dose and 25% dose reduction examinations was significantly higher than that of the 50% dose reduction examinations ( = .011 and .012, respectively) but not different from one another ( = .866). Dose was not a significant predictor of time to complete each case, and subspecialty was not a significant predictor of sensitivity or false-positive results.

Conclusion: Sensitivity for lesion detection significantly decreased as dose decreased; however, confidence did not change between the full-dose and 25% reduced-dose scans. This suggests that readers are unaware of this decrease in performance, which should be accounted for in clinical dose reduction efforts. Abdomen/GI, CT, Liver, Observer Performance, Pediatrics, Perception Image© RSNA, 2019.
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http://dx.doi.org/10.1148/rycan.2019190027DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7983686PMC
September 2019

Correlation of preoperative imaging characteristics with donor outcomes and operative difficulty in laparoscopic donor nephrectomy.

Am J Transplant 2020 03 23;20(3):752-760. Epub 2019 Oct 23.

Department of Surgery, Duke University, Durham, North Carolina.

This study aimed to understand the relationship of preoperative measurements and risk factors on operative time and outcomes of laparoscopic donor nephrectomy. Two hundred forty-two kidney donors between 2010 and 2017 were identified. Patients' demographic, anthropomorphic, and operative characteristics were abstracted from the electronic medical record. Glomerular filtration rates (GFR) were documented before surgery, within 24 hours, 6, 12, and 24 months after surgery. Standard radiological measures and kidney volumes, and subcutaneous and perinephric fat thicknesses were assessed by three radiologists. Data were analyzed using standard statistical measures. There was significant correlation between cranio-caudal and latero-lateral diameters (P < .0001) and kidney volume. The left kidney was transplanted in 92.6% of cases and the larger kidney in 69.2%. Kidney choice (smaller vs. larger) had no statistically significant impact on the rate of change of donor kidney function over time adjusting for age, sex and race (P = .61). Perinephric fat thickness (+4.08 minutes) and surgery after 2011 were significantly correlated with operative time (P ≤ .01). In conclusion, cranio-caudal diameters can be used as a surrogate measure for volume in the majority of donors. Size may not be a decisive factor for long-term donor kidney function. Perinephric fat around the donor kidney should be reported to facilitate operative planning.
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http://dx.doi.org/10.1111/ajt.15608DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7042043PMC
March 2020

Validation of algorithmic CT image quality metrics with preferences of radiologists.

Med Phys 2019 Nov 20;46(11):4837-4846. Epub 2019 Sep 20.

Clinical Imaging Physics Group, Medical Physics Graduate Program, Carl E. Ravin Advanced Imaging Laboratories, Departments of Radiology, Physics, Biomedical Engineering, and Electrical and Computer Engineering, Duke University, 2424 Erwin Rd, Suite 302, Durham, NC, 27705, USA.

Purpose: Automated assessment of perceptual image quality on clinical Computed Tomography (CT) data by computer algorithms has the potential to greatly facilitate data-driven monitoring and optimization of CT image acquisition protocols. The application of these techniques in clinical operation requires the knowledge of how the output of the computer algorithms corresponds to clinical expectations. This study addressed the need to validate algorithmic image quality measurements on clinical CT images with preferences of radiologists and determine the clinically acceptable range of algorithmic measurements for abdominal CT examinations.

Materials And Methods: Algorithmic measurements of image quality metrics (organ HU, noise magnitude, and clarity) were performed on a clinical CT image dataset with supplemental measures of noise power spectrum from phantom images using techniques developed previously. The algorithmic measurements were compared to clinical expectations of image quality in an observer study with seven radiologists. Sets of CT liver images were selected from the dataset where images in the same set varied in terms of one metric at a time. These sets of images were shown via a web interface to one observer at a time. First, the observer rank ordered the CT images in a set according to his/her preference for the varying metric. The observer then selected his/her preferred acceptable range of the metric within the ranked images. The agreement between algorithmic and observer rankings of image quality were investigated and the clinically acceptable image quality in terms of algorithmic measurements were determined.

Results: The overall rank-order agreements between algorithmic and observer assessments were 0.90, 0.98, and 1.00 for noise magnitude, liver parenchyma HU, and clarity, respectively. The results indicate a strong agreement between the algorithmic and observer assessments of image quality. Clinically acceptable thresholds (median) of algorithmic metric values were (17.8, 32.6) HU for noise magnitude, (92.1, 131.9) for liver parenchyma HU, and (0.47, 0.52) for clarity.

Conclusions: The observer study results indicated that these algorithms can robustly assess the perceptual quality of clinical CT images in an automated fashion. Clinically acceptable ranges of algorithmic measurements were determined. The correspondence of these image quality assessment algorithms to clinical expectations paves the way toward establishing diagnostic reference levels in terms of clinically acceptable perceptual image quality and data-driven optimization of CT image acquisition protocols.
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http://dx.doi.org/10.1002/mp.13795DOI Listing
November 2019

Systematic analysis of bias and variability of texture measurements in computed tomography.

J Med Imaging (Bellingham) 2019 Jul 12;6(3):033503. Epub 2019 Jul 12.

Carl E. Ravin Advanced Imaging Laboratories, Durham, North Carolina, United States.

Texture is a key radiomics measurement for quantification of disease and disease progression. The sensitivity of the measurements to image acquisition, however, is uncertain. We assessed bias and variability of computed tomography (CT) texture feature measurements across many clinical image acquisition settings and reconstruction algorithms. Diverse, anatomically informed textures (texture A, B, and C) were simulated across 1188 clinically relevant CT imaging conditions representing four in-plane pixel sizes (0.4, 0.5, 0.7, and 0.9 mm), three slice thicknesses (0.625, 1.25, and 2.5 mm), three dose levels ( 1.90, 3.75, and 7.50 mGy), and 33 reconstruction kernels. Imaging conditions corresponded to noise and resolution properties representative of five commercial scanners (GE LightSpeed VCT, GE Discovery 750 HD, GE Revolution, Siemens Definition Flash, and Siemens Force) in filtered backprojection and iterative reconstruction. About 21 texture features were calculated and compared between the ground-truth phantom (i.e., preimaging) and its corresponding images. Each feature was measured with four unique volumes of interest (VOIs) sizes (244, 579, 1000, and . To characterize the bias, the percentage relative difference [PRD(%)] in each feature was calculated between the imaged scenario and the ground truth for all VOI sizes. Feature variability was assessed in terms of (1)  indicating the variability between the ground truth and simulated image scenario based on the PRD(%), (2)  indicating the simulation-based variability, and (3)  indicating the natural variability present in the ground-truth phantom. The PRD ranged widely from to 1220%, with an underlying variability ( ) of up to 241%. Features such as gray-level nonuniformity, texture entropy, sum average, and homogeneity exhibited low susceptibility to reconstruction kernel effects ( ) with relatively small ( ) across imaging conditions. The dynamic range of results indicates that image acquisition and reconstruction conditions of in-plane pixel sizes, slice thicknesses, dose levels, and reconstruction kernels can lead to significant bias and variability in feature measurements.
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http://dx.doi.org/10.1117/1.JMI.6.3.033503DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6625670PMC
July 2019

Clinical utility of FoundationOne tissue molecular profiling in men with metastatic prostate cancer.

Urol Oncol 2019 11 19;37(11):813.e1-813.e9. Epub 2019 Jul 19.

Department of Medicine, School of Medicine, Duke University, Durham, NC; Duke Cancer Institute Center for Prostate and Urologic Cancer, Durham, NC; Department of Pharmacology and Cancer Biology, Duke University, Durham, NC. Electronic address:

Purpose: Targeted inhibitors and immunotherapy have entered the treatment landscape of metastatic prostate cancer. Genomic testing may uncover which patients benefit most from these therapies. We report the clinical utility and benefits of FoundationOne testing in men with advanced prostate cancer.

Patients And Methods: We retrospectively identified all men with prostate cancer who received tissue FoundationOne testing at our institution between January 2010 and April 2017. Genomic alterations, treatment selection based on FoundationOne results, and clinical outcomes including response and duration of therapy following matched targeted therapy were analyzed.

Results: A total of 77 men with metastatic prostate cancer were referred for FoundationOne testing; 59 (77%) had sufficient tumor tissue for testing. Of these, 22% (17/77) of men had a targetable mutation and 9% (7/77) of men received matched off-label targeted therapy. Overall, 5% (4/77) of patients derived clinical benefit. One patient with a BRCA2 loss had a complete response on olaparib (>27 months) and 3 patients (ATM substitution, PALB2 frameshift, CDK12 frameshift) had stable disease with olaparib (10.3, 18.7, and 7.8 months, respectively). Three patients (BRCA2 frameshift, PDL1 + PDL2 amplification, PMS2 missense) had progressive disease despite targeted therapy.

Conclusions: Tissue genomic testing can uncover patients who may benefit from targeted therapies such as poly(adenosine diphosphate-ribose) polymerase inhibitors or immunotherapy. In our limited single institution study, genomic testing led to clinical benefit in 5% of patients. Combined germline and circulating tumor DNA testing may be helpful to identify additional patients suitable for matched genomic therapies.
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http://dx.doi.org/10.1016/j.urolonc.2019.06.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6823135PMC
November 2019

Pembrolizumab in men with heavily treated metastatic castrate-resistant prostate cancer.

Cancer Med 2019 08 3;8(10):4644-4655. Epub 2019 Jul 3.

Department of Medicine, School of Medicine, Duke University, Durham, North Carolina.

Background: Pembrolizumab is approved for patients with metastatic, microsatellite instability (MSI)-high or mismatch repair-deficient (dMMR) solid tumors. However, very few men with prostate cancer were included in these initial studies.

Methods: We performed a single institution retrospective review of men with metastatic castrate-resistant prostate cancer (mCRPC) who were treated with pembrolizumab. The primary objective was to describe the clinical efficacy of pembrolizumab associated with patient and genomic characteristics.

Results: We identified 48 men who received ≥1 cycle of pembrolizumab for mCRPC. Of these, 94% (45/48) had ≥3 prior lines of therapy for mCRPC. Somatic tumor sequencing was available in 18/48 men (38%). We found that 17% (8/48) had a ≥50% confirmed PSA decline with pembrolizumab, and 8% (4/48) had a ≥90% PSA decline with durations of response ranging from 3.1 to 16.3 months. Two of these four men had mutations in LRP1b, one of whom also had MSH2 loss and was MSI-H and TMB-high. Despite prior progression on enzalutamide, 48% (23/48) of men were treated with concurrent enzalutamide. The median PSA progression-free-survival was 1.8 months (range 0.4-13.7 months), with 31% of patients remaining on pembrolizumab therapy and 54% of men remain alive with a median follow-up of 7.1 months.

Conclusions: In a heavily pretreated population of men with mCRPC, pembrolizumab was associated with a ≥50% PSA decline in 17% (8/48) of men, including a dramatic ≥90% PSA response in 8% (4/48), two of whom harbored pathogenic LRP1b mutations suggesting that LRP1b mutations may enrich for PD-1 inhibitor responsiveness in prostate cancer.
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http://dx.doi.org/10.1002/cam4.2375DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6712455PMC
August 2019

Design and fabrication of heterogeneous lung nodule phantoms for assessing the accuracy and variability of measured texture radiomics features in CT.

J Med Imaging (Bellingham) 2019 Apr 21;6(2):021606. Epub 2019 Jun 21.

Duke University, Department of Radiology, Durham, North Carolina, United States.

We aimed to design and fabricate synthetic lung nodules with patient-informed internal heterogeneity to assess the variability and accuracy of measured texture features in CT. To that end, 190 lung nodules from a publicly available database of chest CT images (Lung Image Database Consortium) were selected based on size ( ) and malignancy. The texture features of the nodules were used to train a statistical texture synthesis model based on clustered lumpy background. The model parameters were ascertained based on a genetic optimization of a Mahalanobis distance objective function. The resulting texture model defined internal heterogeneity within 24 anthropomorphic lesion models which were subsequently fabricated into physical phantoms using a multimaterial three-dimensional (3-D) printer. The 3-D-printed lesions were imbedded in an anthropomorphic chest phantom and imaged with a clinical scanner using different acquisition parameters including slice thickness, dose level, and reconstruction kernel. The imaged lesions were analyzed in terms of texture features to ascertain the impact of CT imaging on lesion texture quantification. The texture modeling method produced lesion models with low and stable Mahalanobis distance between real and synthetic textures. The virtual lesions were successfully printed into 3-D phantoms. The accuracy and variability of the measured features extracted from the CT images of the phantoms showed notable influence from the imaging acquisition parameters with contrast, energy, and texture entropy exhibiting most sensitivity in terms of accuracy, and contrast, dissimilarity, and texture entropy most variability. Thinner slice thicknesses yielded more accurate and edge reconstruction kernels more stable results. We conclude that printed textured models of lesions can be developed using a method that can target and minimize the mathematical distance between real and synthetic lesions. The synthetic lesions can be used as the basis to investigate how CT imaging conditions might affect radiomics features derived from CT images.
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http://dx.doi.org/10.1117/1.JMI.6.2.021606DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6586987PMC
April 2019

ACR Appropriateness Criteria Left Lower Quadrant Pain-Suspected Diverticulitis.

J Am Coll Radiol 2019 May;16(5S):S141-S149

Specialty Chair, Virginia Commonwealth University Medical Center, Richmond, Virginia.

This review summarizes the relevant literature regarding imaging of suspected diverticulitis as an etiology for left lower quadrant pain, and imaging of complications of acute diverticulitis. The most common cause of left lower quadrant pain in adults is acute sigmoid or descending colonic diverticulitis. Appropriate imaging triage for patients with suspected diverticulitis should address the differential diagnostic possibilities and what information is necessary to make a definitive management decision. Patients with diverticulitis may require surgery or interventional radiology procedures because of associated complications, including abscesses, fistulas, obstruction, or perforation. As a result, there has been a trend toward greater use of imaging to confirm the diagnosis of diverticulitis, evaluate the extent of disease, and detect complications before deciding on appropriate treatment. Additionally, in the era of bundled payments and minimizing health care costs, patients with acute diverticulitis are being managed on an outpatient basis and rapid diagnostic imaging at the time of initial symptoms helps to streamline and triage patients to the appropriate treatment pathway. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.
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http://dx.doi.org/10.1016/j.jacr.2019.02.015DOI Listing
May 2019

ACR Appropriateness Criteria Dysphagia.

J Am Coll Radiol 2019 May;16(5S):S104-S115

Panel Chair, University of Wisconsin Hospital & Clinics, Madison, Wisconsin.

This review summarizes the relevant literature for the initial imaging of patients with symptoms of dysphagia. For patients with oropharyngeal dysphagia who have an underlying attributable cause, a modified barium swallow is usually appropriate for initial imaging but for those who have unexplained dysphagia a fluoroscopic biphasic esophagram is usually appropriate. Fluoroscopic biphasic esophagram is usually appropriate for initial imaging in both immunocompetent and immunocompromised patients who have retrosternal dysphagia. For postoperative patients with dysphagia, fluoroscopic single-contrast esophagram and CT neck and chest with intravenous (IV) contrast are usually appropriate for oropharyngeal or retrosternal dysphagia occurring in the early postoperative period where water-soluble contrast is usually preferred rather than barium sulfate. In the later postoperative period (greater than 1 month), CT neck and chest with IV contrast and fluoroscopic single-contrast esophagram are usually appropriate. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.
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http://dx.doi.org/10.1016/j.jacr.2019.02.007DOI Listing
May 2019