Publications by authors named "Unni K Udayasankar"

23 Publications

  • Page 1 of 1

ACR Appropriateness Criteria® Seizures-Child.

J Am Coll Radiol 2021 May;18(5S):S199-S211

Specialty Chair, Riley Hospital for Children Indiana University, Indianapolis, Indiana.

In children, seizures represent an extremely heterogeneous group of medical conditions ranging from benign cases, such as a simple febrile seizure, to life-threatening situations, such as status epilepticus. Underlying causes of seizures also represent a wide range of pathologies from idiopathic cases, usually genetic, to a variety of acute and chronic intracranial or systemic abnormalities. This document discusses appropriate utilization of neuroimaging tests in a child with seizures. The clinical scenarios in this document take into consideration different circumstances at the time of a child's presentation including the patient's age, precipitating event (if any), and clinical and electroencephalogram findings and include neonatal seizures, simple and complex febrile seizures, post-traumatic seizures, focal seizures, primary generalized seizures in a neurologically normal child, and generalized seizures in neurologically abnormal child. This practical approach aims to guide clinicians in clinical decision-making and to help identify efficient and appropriate imaging workup. 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.2021.02.020DOI Listing
May 2021

Magnetic resonance imaging quality control, quality assurance and quality improvement.

Pediatr Radiol 2021 May 27;51(5):698-708. Epub 2021 Mar 27.

Department of Radiology, Massachusetts General Hospital, Boston, MA, USA.

Quality in MR imaging is a comprehensive process that encompasses scanner performance, clinical processes for efficient scanning and reporting, as well as data-driven improvement involving measurement of key performance indicators. In this paper, the authors review this entire process. This article provides a framework for establishing a successful MR quality program. The collective experiences of the authors across a spectrum of pediatric hospitals is summarized here.
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http://dx.doi.org/10.1007/s00247-021-05043-6DOI Listing
May 2021

Performance of overnight on-call radiology residents in interpreting unenhanced abdominopelvic magnetic resonance imaging studies performed for pediatric right lower quadrant abdominal pain.

Pediatr Radiol 2021 Mar 10. Epub 2021 Mar 10.

Department of Medical Imaging, University of Arizona, 1501 N. Campbell, P.O. Box 245067, Tucson, AZ, 85724, USA.

Background: Abdominopelvic magnetic resonance imaging (MRI) is increasingly being used to evaluate children with abdominal pain suspected of having acute appendicitis. At our institution, these examinations are preliminarily interpreted by radiology residents, especially when performed after hours.

Objective: To determine the accuracy of preliminary reports rendered by radiology residents in this setting.

Materials And Methods: Three hundred seventy-seven pediatric abdominopelvic MRI examinations were included. The preliminary (resident) and final (attending) radiology reports were coded as diagnosing acute appendicitis or no acute appendicitis. The concordance between resident and attending radiologist interpretations was calculated. Additionally, both resident and attending reports were compared to available surgical pathology or clinical follow-up data.

Results: Overall concordance rate for the diagnosis of acute appendicitis was 97.1%. Concordance for verified cases of acute appendicitis was 93.4%. Concordance rates did not differ by residents' postgraduate year levels. When compared against surgical pathology or clinical follow-up data, residents demonstrated 91.2% sensitivity and 97.6% specificity. There was no statistically significant difference in the sensitivity or specificity of resident or attending radiologist interpretations.

Conclusion: Radiology residents demonstrate high concordance with attending pediatric radiologists in their interpretations of pediatric abdominopelvic MRI for acute appendicitis. The diagnostic performances of residents and attendings were comparable.
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http://dx.doi.org/10.1007/s00247-021-05009-8DOI Listing
March 2021

Unenhanced MRI for Abdominal Pain in the Pediatric Emergency Department: Point-Safe and Comprehensive Assessment While Reducing Delay in Care.

AJR Am J Roentgenol 2021 04 10;216(4):874-875. Epub 2021 Feb 10.

Department of Medical Imaging, University of Arizona College of Medicine, 1501 N Campbell Ave, Tucson, AZ 85724.

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http://dx.doi.org/10.2214/AJR.20.24392DOI Listing
April 2021

ACR Appropriateness Criteria® Cerebrovascular Disease-Child.

J Am Coll Radiol 2020 May;17(5S):S36-S54

Specialty Chair, Riley Hospital for Children Indiana University, Indianapolis, Indiana.

Stroke is an uncommon but an important and under-recognized cause of morbidity and mortality in children. Strokes may be due to either brain ischemia or intracranial hemorrhage. Common symptoms of pediatric acute stroke include headache, vomiting, focal weakness, numbness, visual disturbance, seizures, and altered consciousness. Most children presenting with an acute neurologic deficit do not have an acute stroke, but have symptoms due to stroke mimics which include complicated migraine, seizures with postictal paralysis, and Bell palsy. Because of frequency of stroke mimics, in children and the common lack of specificity in symptoms, the diagnosis of a true stroke may be delayed. There are a relatively large number of potential causes of stroke mimic and true stroke. Consequently, imaging plays a critical role in the assessment of children with possible stroke and especially in children who present with acute onset of stroke symptoms. 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.2020.01.036DOI Listing
May 2020

ACR Appropriateness Criteria® Head Trauma-Child.

J Am Coll Radiol 2020 May;17(5S):S125-S137

Specialty Chair, Riley Hospital for Children Indiana University, Indianapolis, Indiana.

Head trauma is a frequent indication for cranial imaging in children. The majority of accidental pediatric head trauma is minor and sustained without intracranial injury. Well-validated pediatric-specific clinical decision guidelines should be used to identify very low-risk children who can safely forgo imaging. In those who require acute imaging, CT is considered the first-line imaging modality for suspected intracranial injury because of the short duration of the examination and its high sensitivity for acute hemorrhage. MRI can accurately detect traumatic complications, but often necessitates sedation in children, owing to the examination length and motion sensitivity, which limits rapid assessment. There is a paucity of literature regarding vascular injuries in pediatric blunt head trauma and imaging is typically guided by clinical suspicion. Advanced imaging techniques have the potential to identify changes that are not seen by standard imaging, but data are currently insufficient to support routine clinical use. 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.2020.01.026DOI Listing
May 2020

First-Line Diagnostic Evaluation with MRI of Children Suspected of Having Acute Appendicitis.

Radiology 2019 04 12;291(1):170-177. Epub 2019 Feb 12.

From the Departments of Medical Imaging (R.M., S.M.D., F.M., D.G., S.V., B.K., D.R.M., U.K.U.), Pediatrics (G.G.), and Pediatric Emergency Medicine (A.L.), University of Arizona College of Medicine, 1501 N Campbell Ave, Tucson, AZ 85724.

Background Advances in abdominal MRI have enabled rapid, free-breathing imaging without the need for intravenous or oral contrast material. The use of MRI as the primary imaging modality for suspected appendicitis has not been previously studied. Purpose To determine the diagnostic performance of MRI as the initial imaging modality in children suspected of having acute appendicitis. Materials and Methods The study included consecutive patients 18 years of age and younger presenting with acute abdominal pain at a tertiary care institution from January 2013 through June 2016 who subsequently underwent an unenhanced MRI examination as the primary diagnostic imaging modality. Electronic medical records and radiology reports were retrospectively evaluated for the feasibility and diagnostic performance of MRI, with surgical pathology and follow-up electronic records as reference standards. Statistical analyses were performed by using simple binomial proportions to quantify sensitivity, specificity, and accuracy, and exact 95% confidence intervals (CIs) were obtained. Results After exclusions, 402 patients (median age: 13 years; interquartile range [IQR], 9-15 years; 235 female patients; 167 male patients) were included. Sedation for MRI was required in 13 of 402 patients (3.2%; 95% CI: 1.7%, 5.5%). The appendix was visualized in 349 of 402 patients (86.8%; 95% CI: 83.1%, 90%); for the remaining patients, a diagnosis was provided on the basis of secondary signs of appendicitis. The sensitivity, specificity, and accuracy of MRI as the primary diagnostic imaging modality for the evaluation of acute appendicitis were 97.9% (95 of 97; 95% CI: 92.8%, 99.8%), 99% (302 of 305; 95% CI: 97.2%, 99.8%), and 98.8% (397 of 402; 97.1%, 99.6%), respectively. Among patients with negative findings for appendicitis at MRI, an alternate diagnosis was provided in 113 of 304 patients (37.2%; 95% CI: 31.7%, 42.9%). Conclusion When performed as the initial imaging modality in children suspected of having acute appendicitis, MRI examinations had high diagnostic performance for the diagnosis of acute appendicitis and in providing alternative diagnoses. © RSNA, 2019 See also the editorial by Dillman and Trout in this issue.
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http://dx.doi.org/10.1148/radiol.2019181959DOI Listing
April 2019

Jugular bulb and skull base pathologies: proposal for a novel classification system for jugular bulb positions and microsurgical implications.

Neurosurg Focus 2018 07;45(1):E5

3Department of ENT, University Hospitals Cleveland Medical Center, Cleveland, Ohio.

OBJECTIVE There is no definitive or consensus classification system for the jugular bulb position that can be uniformly communicated between a radiologist, neurootologist, and neurosurgeon. A high-riding jugular bulb (HRJB) has been variably defined as a jugular bulb that rises to or above the level of the basal turn of the cochlea, within 2 mm of the internal auditory canal (IAC), or to the level of the superior tympanic annulus. Overall, there is a seeming lack of consensus, especially when MRI and/or CT are used for jugular bulb evaluation without a dedicated imaging study of the venous anatomy such as digital subtraction angiography or CT or MR venography. METHODS A PubMed analysis of "jugular bulb" comprised of 1264 relevant articles were selected and analyzed specifically for an HRJB. A novel classification system based on preliminary skull base imaging using CT is proposed by the authors for conveying the anatomical location of the jugular bulb. This new classification includes the following types: type 1, no bulb; type 2, below the inferior margin of the posterior semicircular canal (SCC), subclassified as type 2a (without dehiscence into the middle ear) or type 2b (with dehiscence into the middle ear); type 3, between the inferior margin of the posterior SCC and the inferior margin of the IAC, subclassified as type 3a (without dehiscence into the middle ear) and type 3b (with dehiscence into the middle ear); type 4, above the inferior margin of the IAC, subclassified as type 4a (without dehiscence into the IAC) and type 4b (with dehiscence into the IAC); and type 5, combination of dehiscences. Appropriate CT and MR images of the skull base were selected to validate the criteria and further demonstrated using 3D reconstruction of DICOM files. The microsurgical significance of the proposed classification is evaluated with reference to specific skull base/posterior fossa pathologies. RESULTS The authors validated the role of a novel classification of jugular bulb location that can help effective communication between providers treating skull base lesions. Effective utilization of the above grading system can help plan surgical procedures and anticipate complications. CONCLUSIONS The authors have proposed a novel anatomical/radiological classification system for jugular bulb location with respect to surgical implications. This classification can help surgeons in complication avoidance and management when addressing HRJBs.
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http://dx.doi.org/10.3171/2018.5.FOCUS18106DOI Listing
July 2018

Imaging of Pediatric Salivary Glands.

Neuroimaging Clin N Am 2018 May 7;28(2):209-226. Epub 2018 Mar 7.

Department of Medical Imaging, University of Arizona College of Medicine, 1501 North Campbell Avenue, Tucson, AZ 85724, USA.

Salivary gland diseases in children are uncommon, and the relative incidence of pathologies is different than in adults. This article presents a comprehensive review of congenital and acquired disorders that affect the major salivary glands in the pediatric population, highlighting the imaging findings that are important in defining the appropriate diagnosis or narrowing of the differential diagnosis.
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http://dx.doi.org/10.1016/j.nic.2018.01.005DOI Listing
May 2018

Case 252: Acute Hyperammonemic Encephalopathy Resulting from Late-Onset Ornithine Transcarbamylase Deficiency.

Radiology 2018 04;287(1):353-359

From the Department of Medical Imaging, University of Arizona College of Medicine, 1501 N Campbell Ave, Tucson, AZ 85724.

History A 19-year-old woman with no pertinent medical history was brought to the emergency department after being found unconscious on her bathroom floor by her roommate. In the preceding weeks, she had reported intractable nausea and vomiting, for which she had been taking ondansetron. No other medications had been prescribed. The day prior to presentation, she had contacted her mother and described increasing confusion. Glasgow coma scale score on arrival in the emergency department was 4. Intravenous naloxone was administered, without immediate response. Initial blood glucose level was 232 mg/dL (12.8 mmol/L) (normal range, 79-140 mg/dL [4.4- 7.7 mmol/L]), and other routine laboratory test results were normal. Urine toxicology results were negative. Cerebrospinal fluid evaluation revealed levels were within normal limits. Neurologic examination revealed dilated pupils, which showed a sluggish response to light, and left lower extremity rigidity with intermittent tremors. Initial unenhanced cranial computed tomographic (CT) findings were negative. Magnetic resonance (MR) imaging of the brain was performed. The patient's condition deteriorated, with increasing cerebral edema over the next week, and she was declared brain dead. Her liver was transplanted into an adult recipient, who subsequently developed cerebral edema and elevated plasma ammonia levels, resulting in death in the immediate postoperative period.
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http://dx.doi.org/10.1148/radiol.2018161834DOI Listing
April 2018

Case 252.

Radiology 2017 12;285(3):1042-1044

From the Department of Medical Imaging, University of Arizona College of Medicine, 1501 N Campbell Ave, Tucson, AZ 85724.

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http://dx.doi.org/10.1148/radiol.2017161833DOI Listing
December 2017

Pediatric brain MRI part 1: basic techniques.

Pediatr Radiol 2017 May 13;47(5):534-543. Epub 2017 Apr 13.

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

Pediatric neuroimaging is a complex and specialized field that uses magnetic resonance (MR) imaging as the workhorse for diagnosis. Standard MR techniques used in adult neuroimaging are suboptimal for imaging in pediatrics because there are significant differences in the child's developing brain. These differences include size, myelination and sulcation. MR protocols need to be tailored to the specific indication and reviewed by the supervising radiologist in real time, and the specialized needs of this population require careful consideration of issues such as scan timing, sequence order, sedation, anesthesia and gadolinium administration. In part 1 of this review, we focus on basic protocol development and anatomical characterization. We provide multiple imaging examples optimized for evaluation of supratentorial and infratentorial brain, midline structures, head and neck, and intracranial vasculature.
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http://dx.doi.org/10.1007/s00247-016-3776-7DOI Listing
May 2017

Pediatric brain MRI, Part 2: Advanced techniques.

Pediatr Radiol 2017 May 13;47(5):544-555. Epub 2017 Apr 13.

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

Pediatric neuroimaging is a complex and specialized field that uses magnetic resonance (MR) imaging as the workhorse for diagnosis. MR protocols should be tailored to the specific indication and reviewed by the supervising radiologist in real time. Targeted advanced imaging sequences can be added to provide information regarding tissue microstructure, perfusion, metabolism and function. In part 2 of this review, we highlight the utility of advanced imaging techniques for superior evaluation of pediatric neurologic disease. We focus on the following techniques, with clinical examples: phase-contrast imaging, perfusion-weighted imaging, vessel wall imaging, diffusion tensor imaging, task-based functional MRI and MR spectroscopy.
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http://dx.doi.org/10.1007/s00247-017-3792-2DOI Listing
May 2017

Cat Scratch Disease: Expanded Spectrum.

Ocul Oncol Pathol 2016 Oct 1;2(4):246-250. Epub 2016 Jul 1.

Department of Ophthalmology, Cole Eye Institute, Ohio, USA.

Background: To expand the spectrum of ophthalmic manifestations in cat scratch disease.

Methods: Case report.

Results: A 7-year-old male was referred for evaluation of his left optic disc after failing vision screening test at school. His visual acuity was 20/20 OD and light perception OS. Fundus examination showed a left optic disc lesion associated with an exudative retinal detachment and vitreous seeding. Ultrasonography revealed a 7 × 7.5 × 3.8 mm lesion with a possible 6.3 mm of retrolaminar extension into the substance of the optic nerve. Brain MRI did not show evidence of optic nerve involvement but revealed a 6-mm nodule of the pineal gland suggestive of a pineoblastoma. Enucleation was performed and histopathology revealed a suppurative granulomatous inflammation suggestive of infection. Upon further questioning, the patient had recent exposure to kittens with areas of cat scratches along both of his arms. He was subsequently referred to and treated with a 2-week course of trimethoprim-sulfamethoxazole and rifampin by the pediatric infectious disease specialist. Repeat brain MRI showed interval total resolution of enlarged pineal gland. Optic nerve granulomas are a rare presentation of cat scratch disease and could potentially masquerade as retinoblastoma.
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http://dx.doi.org/10.1159/000447063DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5091126PMC
October 2016

Comparison of magnetic resonance enterography with endoscopy, histopathology, and laboratory evaluation in pediatric Crohn disease.

J Pediatr Gastroenterol Nutr 2012 Aug;55(2):178-84

Division of Pediatric Gastroenterology Hepatology and Nutrition, Emory University School of Medicine, Children's Healthcare of Atlanta, Atlanta, GA 30322, USA.

Background And Objective: Children with Crohn disease (CD) often undergo cross-sectional imaging during clinical evaluation. Magnetic resonance enterography (MRE) is becoming the preferred radiologic assessment due to the lack of radiation exposure; however, there are few data in children with CD comparing MRE with objective disease measures. The aim of the present study was to compare MRE with endoscopy, histopathology, and laboratory evaluation in children with CD.

Methods: We performed an institutional review board-approved query of our prospective CD MRE database, which includes data in children with CD undergoing MRE since 2008.

Results: A total of 147 MRE studies were performed in 119 different children with symptomatic CD. Of those, 53 (39.6%) MRE studies were performed at diagnosis to evaluate small bowel disease burden. A total of 117 (79.6%) MRE studies displayed active and/or chronic disease, whereas 30 (20.4%) MRE studies were normal. When compared with normal MRE studies, active inflammation on MRE was associated with a higher mean C-reactive protein (3.6 vs 1.1, P < 0.001), higher erythrocyte sedimentation rate (36 vs 22, P = 0.0.31), higher platelet value (439 vs 352, P = 0.033), and lower albumin (3.4 vs 3.7, P = 0.049). Comparison between MRE and endoscopy demonstrated excellent agreement when ulcers were present, and moderate agreement with histopathology.

Conclusions: Active inflammation on MRE is associated with higher C-reactive protein, erythrocyte sedimentation rate, platelets, and lower albumin in children with CD. MRE displays excellent agreement with endoscopic disease described by ulcers but poor agreement with mild mucosal disease described by erythema and friability. The present study adds to a growing body of evidence that MRE provides excellent assessment of inflammation and measures disease activity in CD.
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http://dx.doi.org/10.1097/MPG.0b013e3182598465DOI Listing
August 2012

An optimal contrast dose indicator for the determination of hepatic enhancement in abdominal multidetector computed tomography: comparison of patient attenuation indicator with total body weight and body mass index.

J Comput Assist Tomogr 2010 Nov-Dec;34(6):874-8

Department of Radiology, Emory University School of Medicine, Atlanta, GA 30322, USA.

Purpose: To evaluate a patient attenuation indicator (PAI) as compared with traditional patient-related factors of total body weight and body mass index (BMI) as a predictor of hepatic enhancement in contrast-enhanced abdominal multidetector computed tomography (MDCT).

Materials And Methods: Institutional review board approval was obtained, and the study was Health Insurance Portability and Accountability Act compliant. A total of 77 patients (mean age, 53 years; male-female ratio, 32:45) underwent routine contrast-enhanced abdominal CT on a 16-slice multidetector CT (LightSpeed 16; GE Medical Systems, Milwaukee, Wis). Contrast enhancement was achieved by administering a 120-mL iodine contrast medium (350-mg iodine per milliliter) at an injection rate of 3 mL/s followed by an injection of 40-mL saline at 3 mL/s. Computed tomographic attenuation values (Hounsfield units [HU]) of liver parenchyma, main portal vein, and abdominal aorta were measured in each patient. Statistical analysis was performed with linear regression to determine the correlation of PAI, total body weight, and BMI with abdominal organ enhancement.

Results: The mean of PAI, total body weight, and BMI were 28.0 (range, 22.1-34.2), 79.0 kg (range, 49.6-112.2 kg), and 27.5 kg/m (range, 16.8-43 kg/m), respectively. Mean hepatic enhancement was 128.2 HU (range, 73.6-175 HU), mean main portal vein enhancement was 214.2 HU (range, 118-327 HU), and mean abdominal aorta enhancement was 208.9 HU (range, 116-395 HU). Patient attenuation indicator, total body weight, and BMI showed a negative correlation with liver enhancement (r = -0.55, r = -0.4, and r = -0.3, respectively). Patient attenuation indicator exhibited a significantly higher correlation with hepatic enhancement than total body weight and BMI (P < 0.01, respectively).

Conclusions: Patient attenuation indicator exhibits a moderately inverse correlation with liver enhancement that is greater than those of total body weight and BMI. Patient attenuation indicator may be reliable in predicting the hepatic enhancement degree for a given dose of contrast material and has a potential use in customizing individual patient contrast medium dose during contrast-enhanced abdominal CT.
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http://dx.doi.org/10.1097/RCT.0b013e3181ed2f72DOI Listing
January 2011

Patient size compensated automatic tube current modulation in multi-detector row CT of the abdomen and pelvis.

Acad Radiol 2011 Feb 13;18(2):205-11. Epub 2010 Nov 13.

Department of Radiology, Emory University School of Medicine, Atlanta, GA 30322, USA.

Rationale And Purpose: To evaluate the performance of a patient size-compensated automatic tube current modulation (PSC-AutomA) technique from the perspectives of image quality and radiation dose in multi-detector-row computed tomography (MDCT) scan of the abdomen and pelvis.

Materials And Methods: Institutional review board approval was obtained and the study was Health Insurance Portability and Accountability Act-compliant. One hundred and seventeen patients (mean age: 48.8 years; range: 17-89 years; male/female: 57/60) underwent abdominal-pelvic CT scan on a 64-slice MDCT using the noise indexes (NI) recommended by the PSC-AutomA technique. Two radiologists independently evaluated all examinations for noise, streak artifacts, and diagnostic acceptability at the dome of liver, porta hepatis, and the upper margin of acetabulum. The CT dose index (CTDI) volume and effective dose of the CT performed using a recommended NI were compared to the CT performed using a fixed NI of 12. Statistical analysis of the data was performed with nonparametric tests.

Results: The NI recommended by the PSC-AutomA technique was strongly correlated with patient size (r = 0.98, P < .001) with a mean NI of 14.2 HU. The recommended NI of 98.2% (115/117) patients was different from the fixed NI of 12. Approximately 71.8% (84/117) subjects were scanned with a NI higher than 12, whereas 26.5% (31/117) subjects were scanned with a NI lower than 12. All examinations (100%; 117/117) were graded as possessing diagnostic image quality. Compared with the CT performed by using a fixed NI 12, the overall CTDI and effective dose reduction by the PSC-AutomA technique were 11.1% and 11.8%, respectively.

Conclusion: The PSC-AutomA technique can recommend an appropriate NI in MDCT scan of the abdomen and pelvis according to patient size, allowing a balanced optimization of both radiation dose and image quality, simultaneously.
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http://dx.doi.org/10.1016/j.acra.2010.09.014DOI Listing
February 2011

CT-guided liver biopsy: correlation of procedure time and radiation dose with patient size, weight, and lesion volume and depth.

Clin Imaging 2010 Jul-Aug;34(4):263-8

Department of Radiology, Emory University School of Medicine, Atlanta, GA 30322, USA.

Purpose: The purpose of this study was to retrospectively evaluate the effect of various factors, including overall patient size, weight, and individual lesion characteristics, on the radiation dose and procedure time required to successfully perform computed tomography (CT)-guided liver lesion biopsies.

Materials And Methods: This Institutional-Review-Board-approved study included 209 patients (average age, 59 years; range, 19-86 years; 105 males, 104 females) who underwent CT-guided liver lesion biopsy on a four-slice multidetector row CT scanner (LightSpeed Qx/i; GE Healthcare, Milwaukee, WI). Medical records and images were retrospectively reviewed to obtain the following data: (a) patient weight, (b) patient size, (c) lesion volume, (d) lesion depth, (e) CT dose index (CTDI) and effective radiation dose, and (f) procedure time. Statistical analysis was performed with multiple linear regression to assess the effect of various parameters on radiation dose and procedure time.

Results: CTDI was significantly correlated with patient weight (P<.01), size (P=.03), and lesion volume (P<.01). The total effective radiation dose was significantly correlated with patient size (P<.01) and lesion depth (P<.01). Total procedure time was significantly correlated with lesion volume (P<.01) and depth (P<.01). There was a positive correlation between procedure time and effective radiation dose (r(2)=.57).

Conclusion: In the current study, CT-guided liver lesion biopsy patient radiation dose was associated with both overall patient-specific features (weight and size) and specific lesion characteristics; however, the procedure duration was determined by lesion characteristics (lesion volume and depth) alone.
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http://dx.doi.org/10.1016/j.clinimag.2009.06.029DOI Listing
November 2010

Role of PET/CT in congenital histiocytosis.

Pediatr Radiol 2010 Dec 11;40 Suppl 1:S57-61. Epub 2010 Jul 11.

Department of Radiology, Emory University School of Medicine, 1364 Clifton Road NE, Atlanta, GA 30322, USA.

Congenital Langerhans cell histiocytosis (LCH) is a rare, but often severe, form of LCH. Although a more benign single-system congenital LCH has been described, most cases present as multisystem disease with poorer prognosis and are often treated with systemic chemotherapy. Imaging plays a central role in diagnosis, initial staging and assessment of treatment response. PET/CT is increasingly utilized for pediatric LCH. We report a unique case with PET/CT used as an imaging tool in staging and evaluating treatment response in congenital multisystem LCH.
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http://dx.doi.org/10.1007/s00247-010-1765-9DOI Listing
December 2010

Role of spectral presaturation attenuated inversion-recovery fat-suppressed T2-weighted MR imaging in active inflammatory bowel disease.

J Magn Reson Imaging 2008 Nov;28(5):1133-40

Department of Radiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.

Purpose: To retrospectively evaluate the efficacy of spectral presaturation attenuated inversion-recovery (SPAIR) fat-suppressed (FS) partial Fourier single shot (SSH) T2-weighted (T2W) and gadolinium-enhanced (Gd) FS 3D-gradient echo (3DGRE) T1-weighted (T1W) delayed phase MRI to differentiate active bowel inflammation from fibrotic disease in patients with Crohn's disease (CD).

Materials And Methods: MRI studies of 81 patients (mean age, 43 years; range, 22-77 years; M:F ratio 33:48) had T2W and T1W imaging including SPAIR-SSH and delayed Gd-3DGRE. The ability to assess disease activity in bowel segments affected were retrospectively evaluated by a grading scheme based on subjective analysis of signal intensities. These results were compared against the standard clinical parameters of disease activity.

Results: SPAIR-SSH images correlated better (r=0.74, P<0.0001) with activity than delayed Gd-3DGRE (r=0.39, P=0.0003), with a significant difference between the two techniques (P<0.0001). SPAIR-SSH images showed higher specificity in detection of severely active disease in per patient (98%) and segmental (98%) analysis compared to Gd-3DGRE (57%, 70%). Gd-3DGRE technique showed significantly higher sensitivity (P=0.01) in identifying active disease in per patient (83%) and segmental (85%) analysis compared to SPAIR-SSH (70%, 64%).

Conclusion: SPAIR-SSH detects actively diseased CD bowel segments with a high level of specificity. Noninflammatory bowel fibrosis corresponds to abnormal uptake on delayed phase Gd-3DGRE images but without associated elevated abnormal signal on SPAIR-SSH.
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http://dx.doi.org/10.1002/jmri.21574DOI Listing
November 2008

Acute abdominal pain: value of non-contrast enhanced ultra-low-dose multi-detector row CT as a substitute for abdominal radiographs.

Emerg Radiol 2009 Jan 3;16(1):61-70. Epub 2008 Jul 3.

Division of Abdominal Imaging, Department of Radiology, Emory University School of Medicine, 1364 Clifton Road NE, Atlanta, GA 30322, USA.

The aim of this study was to evaluate a non-enhanced ultra-low-dose (ULD) abdominal-pelvic multi-detector row computerized tomography (MDCT) to assess patients with acute abdominal pain who would otherwise undergo three-view abdominal X-ray series. Institutional review board approval was obtained with waiver of informed consent. This study was Health Insurance Portability and Accountability Act-compliant. One hundred and sixty-three patients (mean age, 51 years; range, 19-82 years, M/F = 110:53) who underwent ULD MDCT were included in the study. Two subspecialty radiologists independently reviewed the images for abnormal findings and image quality parameters. The effective radiation dose was calculated for each patient and compared to standard-dose computed tomography (CT) scans of 50 matched controls. Findings were confirmed by reviewing the patients' medical records, and statistical analysis was performed. ULD MDCT showed a high sensitivity (100%), specificity (98.5%), and positive predictive value (91.7%) for detection of free air, stones, and intestinal obstruction. For other sources of abdominal pain, the overall sensitivity, specificity, and positive predictive value were 86%, 96%, and 95%, respectively. Mean effective radiation dose from this study was 2.10 mSv (range of 0.67 to 6.64 mSv) with a 78% mean dose reduction compared to standard-dose CT. There was good inter-observer agreement (=0.4 to 0.81). ULD abdominal-pelvic MDCT provides rapid and reasonably accurate diagnostic information in patients with acute abdominal pain at a very low radiation dose.
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http://dx.doi.org/10.1007/s10140-008-0743-0DOI Listing
January 2009

Application of automatic vertical positioning software to reduce radiation exposure in multidetector row computed tomography of the chest.

Invest Radiol 2008 Jun;43(6):447-52

Department of Radiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.

Objective: To determine the effect of automatic vertical positioning (AVP) software on radiation dose reduction in multidetector row computed tomography of the chest.

Materials And Methods: Two hundred forty-three consecutive patients (mean age, 54; range, 20-93 years), who underwent 64-slice multidetector row computed tomography of the chest from November 2005 to April 2006, were included in this study. This study was approved by our institutional review board with waiver of informed consent. Technologists initially positioned the patient in the gantry by adjusting the table height (vertical positioning) using a laser guidance system and patient surface anatomy. AVP software was then used to determine the true vertical positioning of the patient based on matching the individual patient's mean centroid (center of mass) throughout the chest as determined by the lateral projection with the gantry isocenter and center of the bow-tie filter. The resultant reduction in surface radiation dose with this attenuation-based vertical positioning was then calculated. Software-determined changes in patient vertical positioning and resultant radiation dose savings were analyzed using the t test and Pearson correlation statistics.

Results: Vertical positioning of the patients by the technologist differed from AVP with the bow-tie filter in 95.5% (232 of 243) of patients with an average vertical mispositioning distance of 33.2 +/- 1.1 mm (range, 5.1-97 mm). Among mispositioned patients, 97% (225 of 232) were vertically mispositioned below the isocenter with a mean distance of 33.8 +/- 1.1 mm (range, 5.1-97 mm) and 3% (7 of 232) patients were vertically mispositioned above the isocenter, with a mean distance of 12.7 +/- 2.8 mm (range, 6-28 mm). The average surface radiation dose reduction with AVP software was 19% +/- 1% (range, 1%-46.6%). There was a strong correlation between vertical mispositioning distance and the surface radiation dose reduction facilitated by AVP software (r(2) = 0.9, P < 0.001).

Conclusion: AVP software can help in optimum patient vertical positioning leading to substantial reduction in surface radiation dose.
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http://dx.doi.org/10.1097/RLI.0b013e318169005eDOI Listing
June 2008

Automatic patient centering for MDCT: effect on radiation dose.

AJR Am J Roentgenol 2007 Feb;188(2):547-52

Department of Radiology, Emory University School of Medicine, 1364 Clifton Rd. NE, Atlanta, GA 30322, USA.

Objective: The purpose of this study was to determine with phantom and patient imaging the effect of an automatic patient-centering technique on the radiation dose associated with MDCT.

Subjects And Methods: A 32-cm CT dose index (CTDI) phantom was scanned with 64-MDCT in three positions: gantry isocenter and 30 and 60 mm below the isocenter of the scanner gantry. In each position, surface, peripheral, and volume CTDIs were estimated with a standard 10-cm pencil ionization chamber. The institutional review board approved the study with 63 patients (36 men, 27 women; mean age, 51 years; age range, 22-83 years) undergoing chest (n = 18) or abdominal (n = 45) CT using the z-axis automatic exposure control technique. Each patient was positioned according to the region being scanned and then was centered in the gantry. Before scanning of a patient, automatic centering software was used to estimate patient off-centering and percentage of dose reduction with optimum recentering. Data were analyzed with linear correlation and the Student's t test.

Results: Peripheral and surface CTDIs increased approximately 12-18% with 30-mm off-center distance and 41-49% with 60-mm off-center distance. Approximately 95% (60/63) of patients were not positioned accurately in the gantry isocenter. The mean radiation dose saving with automatic centering of all patients was 13.0% +/- 0.9% (range, 2.6-29.9%). There was strong correlation between off-center distance and percentage of surface CTDI reduction with recentering of patients in the gantry isocenter (r2 = 0.85, p < 0.0001).

Conclusion: Surfaces doses can be reduced if radiologic technologists can better center patients within the CT gantry. Automatic centering technique can help in optimum patient centering and result in as much as 30% reduction in surface dose.
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http://dx.doi.org/10.2214/AJR.06.0370DOI Listing
February 2007