Daniel J. Podberesky

Use of Magnetic Resonance Elastography to Assess Hepatic Fibrosis in Children with Chronic Liver Disease

Management of pediatric chronic liver disease is limited by lack of validated noninvasive biomarkers of histologic severity. We demonstrate that magnetic resonance elastography is feasible and accurate in detecting significant hepatic fibrosis in a case series of 35 children with chronic liver disease, including severely obese children.

Diagnostic Reference Ranges for Pediatric Abdominal CT

PURPOSE To develop diagnostic reference ranges (DRRs) and a method for an individual practice to calculate site-specific reference doses for computed tomographic (CT) scans of the abdomen or abdomen and pelvis in children on the basis of body width (BW). MATERIALS AND METHODS This HIPAA-compliant multicenter retrospective study was approved by institutional review boards of participating institutions; informed consent was waived. In 939 pediatric patients, CT doses were reviewed in 499 (53%) male and 440 (47%) female patients (mean age, 10 years). Doses were from 954 scans obtained from September 1 to December 1, 2009, through Quality Improvement Registry for CT Scans in Children within the National Radiology Data Registry, American College of Radiology. Size-specific dose estimate (SSDE), a dose estimate based on BW, CT dose index, dose-length product, and effective dose were analyzed. BW measurement was obtained with electronic calipers from the axial image at the splenic vein level after completion of the CT scan. An adult-sized patient was defined as a patient with BW of 34 cm. An appropriate dose range for each DRR was developed by reviewing image quality on a subset of CT scans through comparison with a five-point visual reference scale with increments of added simulated quantum mottle and by determining DRR to establish lower and upper bounds for each range. RESULTS For 954 scans, DRRs (SSDEs) were 5.8-12.0, 7.3-12.2, 7.6-13.4, 9.8-16.4, and 13.1-19.0 mGy for BWs less than 15, 15-19, 20-24, 25-29, and 30 cm or greater, respectively. The fractions of adult doses, adult SSDEs, used within the consortium for patients with BWs of 10, 14, 18, 22, 26, and 30 cm were 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9, respectively. CONCLUSION The concept of DRRs addresses the balance between the patients risk (radiation dose) and benefit (diagnostic image quality). Calculation of reference doses as a function of BW for an individual practice provides a tool to help develop site-specific CT protocols that help manage pediatric patient radiation doses.

Hepatic pathology after Fontan palliation: spectrum of imaging findings

BackgroundPatients with congenital heart disease corrected by Fontan palliation have chronic liver congestion that commonly progresses to fibrosis and cirrhosis with resultant complications.ObjectiveTo define the hepatic imaging characteristics associated with Fontan circulation.Materials and methodsA retrospective study was performed in patients who underwent Fontan palliation who had CT or MR examinations including the liver. The liver was evaluated for parenchymal morphology, abnormal enhancement, nodules and imaging findings of fibrosis and cirrhosis.ResultsMRI or CT examinations including the liver were evaluated in 42 Fontan patients. The most common imaging finding was abnormal parenchymal enhancement, present in 38 patients. Hypervascular nodules were present in 13 patients (31%). Imaging findings of cirrhosis were seen in eight patients (19%). One patient with cirrhosis had a large liver mass, subsequently diagnosed as fibrolamellar hepatocellular carcinoma.ConclusionA high percentage of patients had imaging abnormalities of the liver, chiefly abnormal parenchymal enhancement, which became more apparent as the duration of the Fontan circulation increased. The hypervascular nodules sometimes present had imaging characteristics most closely resembling those of focal nodular hyperplasia. The underlying fibrosis and eventual development of cirrhosis raise the risk of developing hepatocellular carcinoma.

Characterization of pediatric liver lesions with gadoxetate disodium.

Gadoxetate disodium (Gd-EOB-DTPA) is a relatively new hepatobiliary MRI contrast agent. It is increasingly used in adults to characterize hepatic masses, but there is little published describing its use in children. The purpose of this paper is to describe our pediatric MRI protocol as well as the imaging appearance of pediatric liver lesions using gadoxetate disodium. As a hepatocyte-specific MRI contrast agent, Gd-EOB-DTPA has the potential to improve characterization and provide a more specific diagnosis of pediatric liver masses.

ACR Appropriateness Criteria® on Suspected Physical Abuse—Child

The appropriate imaging for pediatric patients being evaluated for suspected physical abuse depends on the age of the child, the presence of neurologic signs and symptoms, evidence of thoracic or abdominopelvic injuries, and whether the injuries are discrepant with the clinical history. The clinical presentations reviewed consider these factors and provide evidence-based consensus recommendations by the ACR Appropriateness Criteria(®) Expert Panel on Pediatric Imaging.

CT and MR enterography in children and adolescents with inflammatory bowel disease.

The term inflammatory bowel disease (IBD) is used to describe multiple idiopathic disorders of the gastrointestinal tract. As many as one-quarter of patients with IBD initially present in childhood or adolescence. Multiple methods can be used to diagnose IBD in this age group, including computed tomographic (CT) enterography, magnetic resonance (MR) enterography, small bowel follow-through examination, ileocolonoscopy, and capsule endoscopy. However, CT enterography and MR enterography have become the imaging modalities of choice due to their exquisite image quality, rapid acquisition time, lack of need for bowel preparation, and ability to help diagnose the extraintestinal complications of IBD. In addition to being radiation free, MR enterography can help evaluate peristalsis, has high contrast resolution, and allows the use of diffusion-weighted imaging. The authors discuss the use of CT enterography and MR enterography in the context of pediatric IBD in terms of advantages and disadvantages, protocol, and imaging findings.

Hepatoblastoma imaging with gadoxetate disodium-enhanced MRI--typical, atypical, pre- and post-treatment evaluation.

Gadoxetate disodium (Gd-EOB-DTPA) is a hepatobiliary MRI contrast agent widely used in adults for characterization of liver tumors and increasingly used in children. Hepatoblastoma is the most common primary hepatic malignancy of childhood. In this review, we describe our experience with this agent both before and after initiating therapy in children with hepatoblastoma.

Pediatric Liver MR Elastography

IntroductionMany chronic pediatric liver disorders are complicated by the development of fibrosis and ultimately cirrhosis. Although hepatic fibrogenesis progresses along a common pathway irrespective of the specific etiology, fibrosis in pediatric liver diseases has different histopathological patterns than in adults. In pediatric liver disease, as in adults, management choices may depend upon the stage of fibrosis at diagnosis. With early intervention, the progression of hepatic fibrosis can be slowed or halted, and in some situations, reversed. While liver biopsy is the gold standard for diagnosing and assessing the presence and degree of fibrosis, it has several disadvantages including the potential for sampling error, the risk of complications, the relatively high cost, and general poor acceptance by pediatric patients and their parents. MR elastography (MRE) is a relatively new imaging technique with the potential for allowing a safe, rapid, cost-effective, and non-invasive evaluation of a wide variety of hepatic diseases by quantitatively evaluating the stiffness of the liver parenchyma. The purpose of this article is to present our initial clinical experience and illustrate our modified technique for the application of liver MRE in pediatric patients at our medical center.Methods and MaterialsPediatric MRE techniques were developed and applied to over 45 patients scanned with our new protocol.ConclusionLiver MRE is a safe, non-invasive method for assessing hepatic fibrosis in pediatric patients.

Relationship of MR elastography determined liver stiffness with cardiac function after Fontan palliation

To use MR elastography to assess liver stiffness in patients with congenital heart disease palliated with the Fontan procedure and correlate findings with cardiac index and other functional parameters obtained during cardiac MRI.

Radiation Dose Estimation for Prospective and Retrospective ECG-Gated Cardiac CT Angiography in Infants and Small Children Using a 320-MDCT Volume Scanner

OBJECTIVE The purpose of this study is to determine patient dose estimates for clinical pediatric cardiac-gated CT angiography (CTA) protocols on a 320-MDCT volume scanner. MATERIALS AND METHODS Organ doses were measured using 20 metal oxide semiconductor field effect transistor (MOSFET) dosimeters. Radiation dose was estimated for volumetrically acquired clinical pediatric prospectively and retrospectively ECG-gated cardiac CTA protocols in 5-year-old and 1-year-old anthropomorphic phantoms on a 320-MDCT scanner. Simulated heart rates of 60 beats/min (5-year-old phantom) and 120 beats/min (1- and 5-year-old phantoms) were used. Effective doses (EDs) were calculated using average measured organ doses and International Commission on Radiological Protection 103 tissue-weighting factors. Dose-length product (DLP) was recorded for each examination and was used to develop dose conversion factors for pediatric cardiac examinations acquired with volume scan mode. DLP was also used to estimate ED according to recently published dose conversion factors for pediatric helical chest examinations. Repeated measures and paired Student t test analyses were performed. RESULTS For the 5-year-old phantom, at 60 beats/min, EDs ranged from 1.2 mSv for a prospectively gated examination to 4.5 mSv for a retrospectively gated examination. For the 5-year-old phantom, at 120 beats/min, EDs ranged from 3.0 mSv for a prospectively gated examination to 4.9 mSv for a retrospectively gated examination. For the 1-year-old phantom, at 120 beats/min, EDs ranged from 2.7 mSv for a prospectively gated examination to 4.5 mSv for a retrospectively gated examination. CONCLUSION EDs for 320-MDCT volumetrically acquired ECG-gated pediatric cardiac CTA are lower than those published for conventional 16- and 64-MDCT scanners.