Publications by authors named "Candice W Bolan"

14 Publications

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Pancreatic steatosis on computed tomography is an early imaging feature of pre-diagnostic pancreatic cancer: A preliminary study in overweight patients.

Pancreatology 2021 Mar 16;21(2):428-433. Epub 2021 Jan 16.

Department of Gastroenterology and Hepatology, Mayo Clinic Jacksonville, Florida, USA.

Background: The prevalence of pancreatic ductal adenocarcinoma (PDAC) is on the rise, driven by factors such as aging and an increasing prevalence of obesity and diabetes mellitus. To improve the poor survival rate of PDAC, early detection is vital. Recently, pancreatic steatosis has gained novel interest as a risk factor for PDAC. This study aimed to investigate if pancreatic steatosis on computed tomography (CT) is an early imaging feature in patients with pre-diagnostic PDAC.

Methods: A retrospective case-control study was performed. Patients diagnosed with PDAC (2010-2016) were reviewed for abdominal non-contrast CT-imaging 1 month-3 years prior to their diagnosis. Cases were matched 1:4 with controls based on age, gender and imaging date. Unenhanced CT-images were evaluated for pancreatic steatosis (pancreas-to-spleen ratio in Hounsfield Units <0.70) by a blinded radiologist and results were compared between cases and controls.

Results: In total, 32 cases and 117 controls were included in the study with a comparable BMI (29.6 and 29.2 respectively, p = 0.723). Pancreatic steatosis was present in 71.9% of cases compared to 45.3% of controls (Odds ratio (OR) 3.09(1.32-7.24), p = 0.009). Adjusted for BMI and diabetes mellitus, pancreatic steatosis on CT remained a significant independent risk factor for PDAC (Adjusted OR 2.70(1.14-6.58), p = 0.037).

Conclusion: Pancreatic steatosis measured on CT is independently associated with PDAC up to three years before the clinical diagnosis in overweight patients. If these data are confirmed, this novel imaging feature may be used to identify high-risk individuals and to stratify the risk of PDAC in individuals that already undergo PDAC screening.
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http://dx.doi.org/10.1016/j.pan.2021.01.003DOI Listing
March 2021

Hepatic Mucinous Cystic Neoplasm Versus Simple Biliary Cyst: Assessment of Distinguishing Imaging Features Using CT and MRI.

AJR Am J Roentgenol 2021 02 23;216(2):403-411. Epub 2020 Dec 23.

Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905.

The purpose of our study was to identify the imaging features that differentiate a hepatic mucinous cystic neoplasm (MCN) from a simple biliary cyst. Surgically resected hepatic MCNs and simple biliary cysts over a 20-year period (October 29, 1997-January 23, 2018) with preoperative CT, MRI, or both were retrospectively identified. Included cases underwent histopathologic confirmation of diagnosis based on the 2010 World Health Organization criteria and blinded imaging review. Various imaging features, including cyst shape and septal enhancement, were assessed for performance. For septate cysts, the relationship of the septation to the cyst wall-that is, arising from the wall without an indentation versus arising from an external macrolobulation-was recorded. Statistical analysis was performed for the imaging features with the chi-square test. The study group comprised 22 hepatic MCNs and 56 simple biliary cysts. A unilocular hepatic cystic lesion was highly predictive of a simple biliary cyst (positive predictive value = 95.2%). The imaging feature of septations arising only from macro-lobulations was 100% specific for a simple biliary cyst on CT ( = 0.001). The presence of septations arising from the cyst wall without indentation was 100% sensitive for hepatic MCN but was only 56.3% specific on CT. Septal enhancement reached 100% sensitivity for hepatic MCN on MRI ( = 0.018). The presence of septations, relationship of the septations to the cyst wall, and septal enhancement were sensitive imaging features in the detection of hepatic MCN. The imaging feature of septations arising only from macrolobulations in the cyst wall was specific for simple biliary cysts on CT and helped differentiate simple biliary cysts from hepatic MCNs.
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http://dx.doi.org/10.2214/AJR.20.22768DOI Listing
February 2021

Vascular applications of ferumoxytol-enhanced magnetic resonance imaging of the abdomen and pelvis.

Abdom Radiol (NY) 2021 05 22;46(5):2203-2218. Epub 2020 Oct 22.

Department of Radiology, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.

Ferumoxytol is an injectable ultrasmall superparamagnetic iron oxide that has been gaining interest regarding its off-label use as an intravenous contrast agent in magnetic resonance imaging (MRI). Due to its large particle size, its use with MRI produces exquisite images of blood vessels with little background contamination or parenchymal enhancement of the abdominopelvic organs, except for the liver and spleen. Because ferumoxytol is neither an iodinated nor a gadolinium-based contrast agent, there are no restrictions for its use in patients with poor renal function. This article will highlight normal features in ferumoxytol-enhanced MRI in the abdomen and pelvis as well as its applications in evaluating vascular pathology, presurgical planning, and other problem solving.
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http://dx.doi.org/10.1007/s00261-020-02817-8DOI Listing
May 2021

Multimodality Imaging of Abdominopelvic Tumors with Venous Invasion.

Radiographics 2020 Nov-Dec;40(7):2098-2116. Epub 2020 Oct 16.

From the Department of Radiology, Mayo Clinic Florida, 4500 San Pablo Rd, Jacksonville, FL 32224.

A broad range of abdominal and pelvic tumors can manifest with or develop intraluminal venous invasion. Imaging features at cross-sectional modalities and contrast-enhanced US that allow differentiation of tumor extension within veins from bland thrombus include the expansile nature of tumor thrombus and attenuation and enhancement similar to those of the primary tumor. Venous invasion is a distinctive feature of hepatocellular carcinoma and renal cell carcinoma with known prognostic and treatment implications; however, this finding remains an underrecognized characteristic of multiple other malignancies-including cholangiocarcinoma, adrenocortical carcinoma, pancreatic neuroendocrine tumor, and primary venous leiomyosarcoma-and can be a feature of benign tumors such as renal angiomyolipoma and uterine leiomyomatosis. Recognition of tumor venous invasion at imaging has clinical significance and management implications for a range of abdominal and pelvic tumors. For example, portal vein invasion is a strong negative prognostic indicator in patients with hepatocellular carcinoma. In patients with rectal cancer, diagnosis of extramural venous invasion helps predict local and distant recurrence and is associated with worse survival. The authors present venous invasion by vascular distribution and organ of primary tumor origin with review of typical imaging features. Common pitfalls and mimics of neoplastic thrombus, including artifacts and anatomic variants, are described to help differentiate these findings from tumor in vein. By accurately diagnosing tumor venous invasion, especially in tumors where its presence may not be a typical feature, radiologists can help referring clinicians develop the best treatment strategies for their patients. RSNA, 2020.
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http://dx.doi.org/10.1148/rg.2020200047DOI Listing
October 2020

Magnetic resonance imaging features in 283 patients with primary biliary cholangitis.

Eur Radiol 2020 Sep 26;30(9):5139-5148. Epub 2020 Apr 26.

Department of Radiology, Mayo Clinic, 200, First Street SW, Rochester, MN, 55905, USA.

Objectives: To evaluate magnetic resonance imaging (MRI) features of the liver in primary biliary cholangitis (PBC).

Methods: We conducted a multicenter retrospective review on 283 patients with PBC who underwent an MRI between 2007 and 2018. Patients with overlap syndromes were excluded. MRI studies were independently reviewed by two abdominal radiologists for liver morphology, signal intensity, postcontrast enhancement, and decompensation. Liver and spleen volumes and normalized liver apparent diffusion coefficient (nlADC) were also calculated. MRI features were correlated with fibrosis stage among a subset of patients who had a liver biopsy within 6 months (n = 72).

Results: The study population was comprised of 283 patients (89% females) and a mean ± SD age of 59.4 ± 11.8 years. Lymphadenopathy (78.1%), periportal hyperintensity (36.7%), and periportal halo sign (27.6%) were the most common features. A positive correlation was found between fibrosis stage and spleen size (r = 0.457, p < 0.001), spleen volume (r = 0.557, p < 0.001) and portal vein diameter (r = 0.287, p = 0.013), and a negative correlation with nlADC (r = - 0.332, p = 0.011). Fibrosis stage also correlated with the presence of surface nodularity (p < 0.001), periportal halo sign (p = 0.04), collaterals (p = 0.033), and splenomegaly (p = 0.002). No significant differences in nlADC values were found in different fibrosis stages. Spleen size and volume were significantly higher in patients with ascites and collaterals (< 0.001). The periportal halo sign was present only in patients with significant fibrosis. None of the MRI features significantly correlated with inflammation grade.

Conclusions: In PBC, presence of periportal halo sign correlates with significant fibrosis. Heterogeneous T2W intensity, heterogeneous postcontrast enhancement, collaterals, spleen size, and spleen volume correlate with fibrosis stage and may be useful for predicting advanced fibrosis.

Key Points: • The presence of periportal halo sign is indicative for significant fibrosis in primary biliary cholangitis. • Liver parenchymal heterogeneous T2 signal intensity, heterogeneous postcontrast enhancement, collaterals, spleen size, and spleen volume correlate with fibrosis stages in PBC and may be useful for predicting advanced fibrosis.
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http://dx.doi.org/10.1007/s00330-020-06855-0DOI Listing
September 2020

Deep Learning to Classify Intraductal Papillary Mucinous Neoplasms Using Magnetic Resonance Imaging.

Pancreas 2019 07;48(6):805-810

Center for Research in Computer Vision, School of Engineering and Computer Science, University of Central Florida, Orlando.

Objective: This study aimed to evaluate a deep learning protocol to identify neoplasia in intraductal papillary mucinous neoplasia (IPMN) in comparison to current radiographic criteria.

Methods: A computer-aided framework was designed using convolutional neural networks to classify IPMN. The protocol was applied to magnetic resonance images of the pancreas. Features of IPMN were classified according to American Gastroenterology Association guidelines, Fukuoka guidelines, and the new deep learning protocol. Sensitivity and specificity were calculated using surgically resected cystic lesions or healthy controls.

Results: Of 139 cases, 58 (42%) were male; mean (standard deviation) age was 65.3 (11.9) years. Twenty-two percent had normal pancreas; 34%, low-grade dysplasia; 14%, high-grade dysplasia; and 29%, adenocarcinoma. The deep learning protocol sensitivity and specificity to detect dysplasia were 92% and 52%, respectively. Sensitivity and specificity to identify high-grade dysplasia or cancer were 75% and 78%, respectively. Diagnostic performance was similar to radiologic criteria. Areas under the receiver operating curves (95% confidence interval) were 0.76 (0.70-0.84) for American Gastroenterology Association, 0.77 (0.70-0.85) for Fukuoka, and 0.78 (0.71-0.85) for the deep learning protocol (P = 0.90).

Conclusions: The deep learning protocol showed accuracy comparable to current radiographic criteria. Computer-aided frameworks could be implemented as aids for radiologists to identify high-risk IPMN.
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http://dx.doi.org/10.1097/MPA.0000000000001327DOI Listing
July 2019

Understanding malignant transformation of endometriosis: imaging features with pathologic correlation.

Abdom Radiol (NY) 2020 06;45(6):1762-1775

Department of Diagnostic Radiology, Abdominal Division, Mayo Clinic Hospital, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.

Purpose: Transformation of benign endometriosis to endometriosis-associated ovarian carcinoma (EAOC) is rare; however, women with endometriosis are four times more likely to develop EAOC which can present 20 years earlier than de novo ovarian cancer. Presenting symptoms are often vague and the radiologist's role in recognizing EAOC is critical for early detection and treatment. Histopathologic evaluation remains the mainstay for definitive diagnosis.

Methods: Using a case-based approach, this article will review the sonographic, CT, and MRI features of EAOC with an emphasis on MRI. Histopathologic correlation of benign and malignant endometriosis will be reviewed.

Results: Multiple factors contribute to the malignant transformation of endometriosis including genetic alterations, hormonal influences, oxidative stress, and inflammation. Malignancy most often occurs in ovarian endometriomas with less common sites involving the rectovaginal septum, rectosigmoid colon, and abdominal wall scars. The most common pathologic subtypes are endometrioid adenocarcinoma and clear cell carcinoma. MRI is the most specific imaging modality for evaluating EAOC. Key MR features include solid enhancing nodules (accentuated by subtraction imaging), nodular septations, loss of T2 shading within the endometrioma, and diffusion restriction.

Conclusions: EAOC is a distinct disease that affects women with benign endometriosis at younger ages than classic ovarian cancer. Understanding the imaging features of malignant transformation of endometriosis is essential for early diagnosis and timely definitive treatment.
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http://dx.doi.org/10.1007/s00261-019-01914-7DOI Listing
June 2020

Lung and Pancreatic Tumor Characterization in the Deep Learning Era: Novel Supervised and Unsupervised Learning Approaches.

IEEE Trans Med Imaging 2019 08 23;38(8):1777-1787. Epub 2019 Jan 23.

Risk stratification (characterization) of tumors from radiology images can be more accurate and faster with computer-aided diagnosis (CAD) tools. Tumor characterization through such tools can also enable non-invasive cancer staging, prognosis, and foster personalized treatment planning as a part of precision medicine. In this papet, we propose both supervised and unsupervised machine learning strategies to improve tumor characterization. Our first approach is based on supervised learning for which we demonstrate significant gains with deep learning algorithms, particularly by utilizing a 3D convolutional neural network and transfer learning. Motivated by the radiologists' interpretations of the scans, we then show how to incorporate task-dependent feature representations into a CAD system via a graph-regularized sparse multi-task learning framework. In the second approach, we explore an unsupervised learning algorithm to address the limited availability of labeled training data, a common problem in medical imaging applications. Inspired by learning from label proportion approaches in computer vision, we propose to use proportion-support vector machine for characterizing tumors. We also seek the answer to the fundamental question about the goodness of "deep features" for unsupervised tumor classification. We evaluate our proposed supervised and unsupervised learning algorithms on two different tumor diagnosis challenges: lung and pancreas with 1018 CT and 171 MRI scans, respectively, and obtain the state-of-the-art sensitivity and specificity results in both problems.
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http://dx.doi.org/10.1109/TMI.2019.2894349DOI Listing
August 2019

Disseminated Peritoneal Leiomyomatosis After Uterine Artery Embolization.

Cardiovasc Intervent Radiol 2018 Dec 7;41(12):1972-1975. Epub 2018 Aug 7.

Department of Radiology, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.

Disseminated peritoneal leiomyomatosis (DPL) is a rare variant of extrauterine leiomyomatosis with reported spontaneous and iatrogenic occurrences. It has been associated with hysterectomy and myomectomy. To our knowledge, reports have not yet substantiated occurrence following uterine artery embolization (UAE), which has become a routine minimally invasive alternative to surgery for the treatment of symptomatic leiomyomata. This report presents the case of a nulliparous premenopausal woman with no other contributory history who presented with DPL 3 years after UAE. The presentation of this patient suggests the potential for a causal relationship between UAE and DPL.
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http://dx.doi.org/10.1007/s00270-018-2044-7DOI Listing
December 2018

MRI evaluation of pancreatic ductal adenocarcinoma: diagnosis, mimics, and staging.

Abdom Radiol (NY) 2019 03;44(3):936-949

Department of Radiology, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.

The radiologist's role in the evaluation of pancreatic ductal adenocarcinoma remains critical in the management of this deadly disease. Imaging plays a vital role in the diagnosis and staging of pancreatic cancer. Although CT is more commonly used for staging pancreatic cancer, MR is increasingly playing an important role in this regard. In our institution, all pancreatic malignancies undergo staging with MRI. In this pictoral essay, we illustrate the MR imaging features of pancreatic ductal adenocarcinoma and its mimics, and we also discuss pearls and pitfalls in MR staging of pancreatic carcinoma.
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http://dx.doi.org/10.1007/s00261-018-1686-xDOI Listing
March 2019

Multispecialty retrospective review of the clinical utility of pelvic magnetic resonance imaging in the setting of pelvic pain.

Transl Androl Urol 2017 Dec;6(6):1155-1158

Department of Urology, Mayo Clinic, Jacksonville, USA.

Background: Pelvic pain is a common complaint, and management of it is often difficult. We sought to evaluate the utility of magnetic resonance imaging (MRI) in the diagnosis of male pelvic pain. Though MRIs are commonly ordered to evaluate pelvic pain, there are very few studies obtaining the efficacy of pelvic MRI in determining a definitive diagnosis. The primary aim of our study was to evaluate the clinical utility of pelvic MRI for a diagnosis code that included pain.

Methods: After receiving institutional review board approval, a retrospective study was performed of all pelvic MRIs completed at our institution from January 2, 2010 to December 31, 2014. These were further delineated into ordering providers by specialty and urology-specific International Classification of Diseases, Ninth Revision (ICD-9) code diagnoses (male pelvic pain, prostatitis, groin pain, scrotal pain, testicular pain, and penile pain). Clinical utility was defined as positive if MRI findings resulted in a change in management. Subanalysis was performed on patients with an ICD-9 co-diagnosis of previous oncologic concern.

Results: A total of 2,643 pelvic MRIs were ordered at our institution over a 5-year period. Of these, 597 pelvic MRIs (23%) were ordered for a diagnosis code that included pain (hip pain, rectal pain, joint pain, penile pain, scrotal pain, male pelvic pain and orchitis). Total utility for MRIs to find anatomic abnormalities potentially responsible for the present pain was 34% (205/597). When ordered by urologic providers, utility was 23%. Oncologists represented the highest positivity rate at 57%.

Conclusions: Chronic pelvic pain is a multispecialty complaint that is difficult to treat. We were surprised to find the large number of both specialists and generalists invested in the management of pelvic pain. The increasing availability of MRI technology makes it a likely candidate to test for a clinically significant anatomic reason for pain. Though MRI is a test with minimal adverse effect and no increased risk of radiation exposure, the cost on the healthcare system should be offset by a clear clinical utility. We found total utility to be 34% across all ordering providers and an increase in positivity with concern of oncologic disease. Therefore, we would recommend pelvic MRIs in the evaluation of patients with refractory pelvic pain.
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http://dx.doi.org/10.21037/tau.2017.10.02DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5760378PMC
December 2017

Cystadenoma of the Rete Testis in a Patient With von Hippel-Lindau Disease.

Urology 2017 Aug 10;106:e5-e6. Epub 2017 May 10.

Department of Radiology, Mayo Clinic, Jacksonville, FL.

von Hippel-Lindau disease is a rare, inherited multicystic disorder that is characterized by several benign and malignant neoplasms (Odrzywolski, 2010). Classically, the disease manifests itself in a broad spectrum, including renal cell carcinomas, intracranial and spinal hemangioblastomas, endolymphatic sac tumors, renal and pancreatic cysts, and pheochromocytomas. Another important, but commonly forgotten manifestation is the cystadenoma of the rete testis.
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http://dx.doi.org/10.1016/j.urology.2017.05.003DOI Listing
August 2017

Diffuse diseases of the myocardium: MRI-pathologic review of cardiomyopathies with dilatation.

AJR Am J Roentgenol 2013 Mar;200(3):W274-82

Department of Radiology, Mayo Clinic, Mayo 2S-131, 4500 San Pablo Rd, Jacksonville, FL 32224, USA.

Objective: In this radiologic-pathologic review of the cardiomyopathies, we present the pertinent imaging findings of diffuse myocardial diseases that are associated with ventricular dilatation, including ischemic cardiomyopathy, nonischemic dilated cardiomyopathy, cardiac sarcoidosis, and iron overload cardiomyopathy.

Conclusion: Correlation of the key radiologic findings with gross and microscopic pathologic features is presented, to provide the reader with a focused and in-depth review of the pathophysiology underlying each entity and the basis for the corresponding imaging characteristics.
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http://dx.doi.org/10.2214/AJR.12.9634DOI Listing
March 2013

Diffuse diseases of the myocardium: MRI-pathologic review of nondilated cardiomyopathies.

AJR Am J Roentgenol 2013 Mar;200(3):W266-73

Department of Radiology, Mayo Clinic, Mayo 2S-131, 4500 San Pablo Rd, Jacksonville, FL 32224, USA.

Objective: This article will present correlation of the key radiologic findings with gross and microscopic pathology for the characterization of diffuse myocardial diseases using advanced imaging techniques. Our goal is to provide a focused and in-depth review of the pathophysiology underlying each entity and to emphasize the structural basis for the corresponding imaging characteristics. This article is limited to those disorders characterized by ventricular wall thickening without chamber dilatation, including hypertrophic cardiomyopathy, hypertensive cardiomyopathy, and cardiac amyloidosis.

Conclusion: For the characterization of diffuse myocardial diseases using advanced imaging techniques, it is essential to understand the underlying pathologic changes in the heart. With these techniques, such as cardiac MRI, the various cardiomyopathies can be differentiated accurately, which may potentially obviate invasive testing and endomyocardial biopsy.
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http://dx.doi.org/10.2214/AJR.12.9633DOI Listing
March 2013