A Multicenter Assessment of Interreader Reliability of LI-RADS Version 2018 for MRI and CT.

Background Various limitations have impacted research evaluating reader agreement for Liver Imaging Reporting and Data System (LI-RADS). Purpose To assess reader agreement of LI-RADS in an international multicenter multireader setting using scrollable images. Materials and Methods This retrospective study used deidentified clinical multiphase CT and MRI and reports with at least one untreated observation from six institutions and three countries; only qualifying examinations were submitted. Examination dates were October 2017 to August 2018 at the coordinating center. One untreated observation per examination was randomly selected using observation identifiers, and its clinically assigned features were extracted from the report. The corresponding LI-RADS version 2018 category was computed as a rescored clinical read. Each examination was randomly assigned to two of 43 research readers who independently scored the observation. Agreement for an ordinal modified four-category LI-RADS scale (LR-1, definitely benign; LR-2, probably benign; LR-3, intermediate probability of malignancy; LR-4, probably hepatocellular carcinoma [HCC]; LR-5, definitely HCC; LR-M, probably malignant but not HCC specific; and LR-TIV, tumor in vein) was computed using intraclass correlation coefficients (ICCs). Agreement was also computed for dichotomized malignancy (LR-4, LR-5, LR-M, and LR-TIV), LR-5, and LR-M. Agreement was compared between research-versus-research reads and research-versus-clinical reads. Results The study population consisted of 484 patients (mean age, 62 years ± 10 [SD]; 156 women; 93 CT examinations, 391 MRI examinations). ICCs for ordinal LI-RADS, dichotomized malignancy, LR-5, and LR-M were 0.68 (95% CI: 0.61, 0.73), 0.63 (95% CI: 0.55, 0.70), 0.58 (95% CI: 0.50, 0.66), and 0.46 (95% CI: 0.31, 0.61) respectively. Research-versus-research reader agreement was higher than research-versus-clinical agreement for modified four-category LI-RADS (ICC, 0.68 vs 0.62, respectively; P = .03) and for dichotomized malignancy (ICC, 0.63 vs 0.53, respectively; P = .005), but not for LR-5 (P = .14) or LR-M (P = .94). Conclusion There was moderate agreement for LI-RADS version 2018 overall. For some comparisons, research-versus-research reader agreement was higher than research-versus-clinical reader agreement, indicating differences between the clinical and research environments that warrant further study. © RSNA, 2023 Supplemental material is available for this article. See also the editorials by Johnson and Galgano and Smith in this issue.

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

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.

Notice of Withdrawal: No Incidence of Nephrogenic Systemic Fibrosis after Gadobenate Dimeglumine Administration in Patients Undergoing Dialysis or Those with Severe Chronic Kidney Disease.

The authors have requested to withdraw this manuscript from publication because the study was not conducted in full accordance with the relevant institutional IRB protocol. © RSNA, 2018.

MRI of patients with implanted cardiac devices.

Cardiac implanted electronic devices (CIEDs) have historically been regarded as a contraindication for performing magnetic resonance imaging (MRI), limiting the availability of this exam for large numbers of patients who may have otherwise benefited from the unique diagnostic capabilities of MRI. Interactions between CIEDs and the magnetic field associated with MRI systems have been documented, and include potential effects on CIED function, lead heating, and force/torque on the generator. Several device manufacturers have developed "MR-Conditional" CIEDs with specific hardware and software design changes to optimize the device for the MR environment. However, a substantial body of evidence has been accumulating that suggests that MRI may be safely performed in patients with either conditional or nonconditional CIEDs. Institutional policies and procedures, including preexam screening and assessment by skilled electrophysiology personnel and intraexam monitoring, allow MRI to be safely performed in CIED patients, as evidenced by at least two, large multicenter prospective studies and multiple smaller, single-institution studies. Cross-departmental collaboration and a robust safety infrastructure at sites that perform MRI should allow for the safe imaging of CIED patients who have a clinical indication for the study, regardless of the conditionality status of the device. LEVEL OF EVIDENCE: 5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2018;47:595-603.

Thoracic versus nonthoracic MR imaging for patients with an MR nonconditional cardiac implantable electronic device.

BACKGROUND: Observational studies have explored the safety of magnetic resonance (MR) scanning of patients with cardiac implantable electronic devices (CIEDs) that are not Food and Drug Administration approved for MR scanning ("nonconditional"). However, concern has been raised that MR scanning that includes the thoracic region may pose a higher risk. This study examines the safety of MR scanning of thoracic versus nonthoracic regions of patients with CIEDs. METHODS: Patients underwent MR scanning utilizing an institutional protocol. CIED variables examined included sensing value, pacing capture threshold, lead impedance, and battery voltage. Regression analysis of the CIED variable differences (pre- to immediately post-MR and pre-MR to long-term follow-up) was performed to determine if CIED variable differences were dependent on region scanned (thoracic vs nonthoracic), time from CIED implant to MR scanning, or CIED type (pacemaker vs implantable cardioverter defibrillator). RESULTS: 238 patients (38% female, age 65 ± 15 years) underwent 339 MR scans, including 99 MR scans of the thoracic region. CIED variable differences to immediately post-MR or to long-term follow-up were not significantly different from zero (P > 0.05) and there was no dependence upon region scanned (thoracic vs nonthoracic), time from CIED implant to MR scan, or CIED type. One power-on reset occurred in a patient that underwent a cardiac MR and the CIED was successfully reprogrammed. There were no clinical adverse effects. CONCLUSIONS: CIED variable differences following MR scan were not dependent on the region scanned (thoracic vs nonthoracic) and there were no clinical adverse effects in this prospective cohort.

Role of Imaging in the Evaluation of Male Infertility.

Infertility is defined herein as the inability to achieve pregnancy after frequently engaging in unprotected sexual intercourse for 1 year. Among infertile couples, the cause of infertility involves the male partner in approximately 50% of cases. Male infertility is usually caused by conditions affecting sperm production, sperm function, or both, or blockages that prevent the delivery of sperm. Chronic health problems, injuries, lifestyle choices, anatomic problems, hormonal imbalances, and genetic defects can have a role in male infertility. The diagnostic workup of male infertility should include a thorough medical and reproductive history, physical examination, and semen analysis, followed by imaging. The main role of imaging is identification of the causes of infertility, such as congenital anomalies and disorders that obstruct sperm transport and may be correctable. Scrotal ultrasonography is the most common initially performed noninvasive examination used to image the male reproductive system, including the testes and extratesticular structures such as the epididymis. Magnetic resonance (MR) imaging is another noninvasive imaging modality used in the pelvis to evaluate possible obstructive lesions involving the ductal system. MR imaging of the brain is extremely useful for evaluating relevant neurologic abnormalities, such as pituitary gland disorders, that are suspected on the basis of hormone analysis results. Invasive techniques are usually reserved for therapeutic interventions in patients with known abnormalities. In this article, the causes and imaging findings of obstructive and nonobstructive azoospermia are discussed. In addition to detecting treatable conditions that are related to male infertility, identifying the life-threatening entities associated with infertility and the genetic conditions that could be transmitted to offspring-especially in patients who undergo assisted reproduction-is critical. ©RSNA, 2017.

Accuracy of Unenhanced MR Imaging in the Detection of Acute Appendicitis: Single-Institution Clinical Performance Review.

PURPOSE: To determine the accuracy of unenhanced magnetic resonance (MR) imaging in the detection of acute appendicitis in patients younger than 50 years who present to the emergency department with right lower quadrant (RLQ) pain. MATERIALS AND METHODS: The institutional review board approved this retrospective study of 403 patients from August 1, 2012, to July 30, 2014, and waived the informed consent requirement. A cross-department strategy was instituted to use MR imaging as the primary diagnostic modality in patients aged 3-49 years who presented to the emergency department with RLQ pain. All MR examinations were performed with a 1.5- or 3.0-T system. Images were acquired without breath holding by using multiplanar half-Fourier single-shot T2-weighted imaging without and with spectral adiabatic inversion recovery fat suppression without oral or intravenous contrast material. MR imaging room time was measured for each patient. Prospective image interpretations from clinical records were reviewed to document acute appendicitis or other causes of abdominal pain. Final clinical outcomes were determined by using (a) surgical results (n = 77), (b) telephone follow-up combined with review of the patient's medical records (n = 291), or (c) consensus expert panel assessment if no follow-up data were available (n = 35). Logistic regression analysis was performed to evaluate the sensitivity and specificity of MR imaging in the detection of acute appendicitis, and corresponding 95% confidence intervals were determined. RESULTS: Of the 403 patients, 67 had MR imaging findings that were positive for acute appendicitis, and 336 had negative findings. MR imaging had a sensitivity of 97.0% (65 of 67) and a specificity of 99.4% (334 of 336). The mean total room time was 14 minutes (range, 8-62 minutes). An alternate diagnosis was offered in 173 (51.5%) of 336 patients. CONCLUSION: MR imaging is a highly sensitive and specific test in the evaluation of patients younger than 50 years with acute RLQ pain that uses a rapid imaging protocol performed without intravenous or oral contrast material.

A Systematic Review and Meta-Analysis of Diagnostic Performance of MRI for Evaluation of Acute Appendicitis.

OBJECTIVE: A meta-analysis was performed to determine the accuracy of MRI in the diagnosis of acute appendicitis in the general population and in subsets of pregnant patients and children. MATERIALS AND METHODS: A systematic search of the PubMed and EMBASE databases for articles published through the end of October 2014 was performed to identify studies that used MRI to evaluate patients suspected of having acute appendicitis. Pooled data for sensitivity, specificity, and positive and negative predictive values were calculated. RESULTS: A total of 30 studies that comprised 2665 patients were reviewed. The sensitivity and specificity of MRI for the diagnosis of acute appendicitis are 96% (95% CI, 95-97%) and 96% (95% CI, 95-97%), respectively. In a subgroup of studies that focused solely on pregnant patients, the sensitivity and specificity of MRI were 94% (95% CI, 87-98%) and 97% (95% CI, 96-98%), respectively, whereas in studies that focused on children, sensitivity and specificity were found to be 96% (95% CI, 95-97%) and 96% (95% CI, 94-98%), respectively. CONCLUSION: MRI has a high accuracy for the diagnosis of acute appendicitis, for a wide range of patients, and may be acceptable for use as a first-line diagnostic test.

Hematospermia Evaluation at MR Imaging.

Hematospermia is a challenging and anxiety-provoking condition that can manifest as a single episode or recur over the course of weeks to months. It is usually a benign self-limiting condition in younger sexually active males without a history of risk factors such as cancer, urogenital malformations, bleeding disorders, and their associated symptoms. However, patients with recurrent, refractory and painful hematospermia with associated symptoms, such as fever, pain, or weight loss, require evaluation through clinical assessment and noninvasive investigations to rule out underlying pathologic conditions such as ejaculatory obstruction, infectious and inflammatory causes, malignancy, vascular malformations, and systemic disorders that increase the risk of bleeding, especially when presenting in older men. If these investigations are negative, the patient should be reassured and treated accordingly. In the recent past, magnetic resonance (MR) imaging has assumed a major role in the investigation of hematospermia due to its excellent soft-tissue contrast and multiplanar capabilities. In this review, we will discuss the potential causes of hematospermia and its diagnostic workup, including pathophysiology, anatomic considerations, the imaging appearance of associated pathologic conditions, and management. (©)RSNA, 2016.

Correcting partial volume effects in biexponential T2 estimation of small lesions.

PURPOSE: T2 mapping provides a quantitative approach for focal liver lesion characterization. For small lesions, a biexponential model should be used to account for partial volume effects (PVE). However, conventional biexponential fitting suffers from large uncertainty of the fitted parameters when noise is present. The purpose of this work is to develop a more robust method to correct for PVE affecting small lesions. METHODS: We developed a region of interest-based joint biexponential fitting (JBF) algorithm to estimate the T2 of lesions affected by PVE. JBF takes advantage of the lesion fraction variation among voxels within a region of interest. JBF is compared to conventional approaches using Cramér-Rao lower bound analysis, numerical simulations, phantom, and in vivo data. RESULTS: JBF provides more accurate and precise T2 estimates in the presence of PVE. Furthermore, JBF is less sensitive to region of interest drawing. Phantom and in vivo results show that JBF can be combined with a reconstruction method for highly undersampled data, enabling the characterization of small abdominal lesions from data acquired in a single breath hold. CONCLUSION: The JBF algorithm provides more accurate and stable T2 estimates for small structures than conventional techniques when PVE is present. It should be particularly useful for the characterization of small abdominal lesions.

Primary biliary tract malignancies: MRI spectrum and mimics with histopathological correlation.

Contrast-enhanced magnetic resonance imaging and magnetic resonance cholangiopancreatography (MRCP), due to their excellent soft tissue contrasts, have become first-line noninvasive tests in the characterization and detection of both hepatic and pancreaticobiliary pathologies. MRCP is also helpful in detecting the level and cause of obstruction in patients presenting with jaundice. Cholangiocarcinoma (CCA) is the most common primary malignant tumor arising from the bile duct epithelium, with extrahepatic tumors presenting more often than with intrahepatic ones. However, the diagnosis and management of CCA is made more complex by a variety of malignant and benign conditions that resemble CCA, including hepatocellular carcinoma variants such as the fibrolamellar variant of hepatocellular carcinoma, cholangiocellular carcinoma, biliary metastases, hepatic inflammatory pseudotumor, lymphoepithelioma-like carcinoma, confluent fibrosis, primary sclerosis cholangitis, and the secondary sclerosing cholangitis complex. Consequently, knowledge of the underlying risk factors and imaging characteristics of these conditions is important in differentiating between neoplastic and non-neoplastic conditions in order to reach a definite diagnosis. Endoscopic retrograde cholangiopancreatography should be reserved for those patients who require intervention or biopsy for histopathological diagnosis.

Magnetic resonance imaging of rectal cancer: staging and restaging evaluation.

Magnetic resonance imaging is used to non-invasively stage and restage rectal adenocarcinomas. Accurate staging is important as the depth of tumor extension and the presence or absence of lymph node metastases determines if an individual will undergo preoperative neoadjuvant chemoradiation. Accurate description of tumor location is important for presurgical planning. The relationship of the tumor to the anal sphincter in addition to the depth of local invasion determines the surgical approach used for resection. High-resolution T2-weighted imaging is the primary sequence used for initial staging. The addition of diffusion-weighted imaging improves accuracy in the assessment of treatment response on restaging scans. Approximately 10%-30% of individuals will experience a complete pathologic response following chemoradiation with no residual viable tumor found in the resected specimen at histopathologic assessment. In some centers, individuals with no residual tumor visible on restaging MR who are thought to be at high operative risk are monitored with serial imaging and a "watch and wait" approach in lieu of resection. Normal rectal anatomy, MR technique utilized for staging and restaging scans, and TMN staging are reviewed. An overview of surgical techniques used for resection including newer, minimally invasive endoluminal techniques is included.

Paraduodenal pancreatitis: clinical performance of MR imaging in distinguishing from carcinoma.

PURPOSE: To evaluate the diagnostic performance of contrast material-enhanced magnetic resonance (MR) imaging for distinguishing paraduodenal pancreatitis (PDP) from pancreatic head duct adenocarcinoma (CA) in patients with diagnoses confirmed by histopathologic analysis. MATERIALS AND METHODS: This retrospective study was approved by the institutional review board and is HIPAA compliant. Between July 2007 and July 2010, 47 patients who underwent Whipple procedure and MR imaging less than 60 days before surgery were identified retrospectively. Two relatively inexperienced fellowship trainees with 9 months of body fellowship training were asked to record the presence or absence of three MR imaging features: focal thickening of the second portion of the duodenum; abnormal enhancement of the second portion of the duodenum; and cystic focus in the expected region of the accessory pancreatic duct. Strict criteria for diagnosis of PDP included presence of all three imaging features. Any case that did not fulfill the criteria was classified as CA. Sensitivity, specificity, positive predictive value, and negative predictive value for characterization of PDP was calculated for each reader with 95% confidence intervals. A κ test assessed level of agreement between readers. RESULTS: Each reader correctly categorized 15 of 17 (88.2%) PDP cases when all three imaging criteria were met. Alternatively, 26 of 30 (86.7%) pancreatic duct CA were correctly categorized as inconsistent with PDP. Four patients with histopathologic diagnosis of CA were incorrectly classified as PDP by each reader. Agreement between the two readers showed substantial κ agreement for the diagnosis of PDP and differentiation from pancreatic duct CA. CONCLUSION: Contrast-enhanced MR imaging may help accurately identify PDP and distinguish it from CA when strict diagnostic criteria are followed. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13112056/-/DC1.

MR imaging for acute nontraumatic abdominopelvic pain: rationale and practical considerations.

Medical imaging is becoming an increasingly vital component of patient care in the emergency department. Computed tomography has been the diagnostic imaging method of choice for emergency department patients with acute abdominopelvic pain; however, the use of ionizing radiation and the potential need for exogenous contrast material adversely affect patient safety and work flow efficiency, respectively. Magnetic resonance (MR) imaging holds promise as an alternative for the evaluation of acute abdominopelvic pain. Critical causes of abdominopelvic pain may be detected with MR imaging without exogenous contrast material. MR imaging is sensitive for depicting tissue or fluid changes related to inflammation, a common process in causes of acute abdominopelvic pain. Fat suppression allows the detection of abnormal signal caused by inflamed tissue. MR imaging has proved sensitive in the detection of acute inflammatory diseases of the gallbladder and bile ducts, liver, pancreas, kidneys, collecting system, bowel, and pelvic soft tissues. Moreover, MR imaging without exogenous contrast material may be safely used in pregnant patients. Evolving roles for emergency department MR imaging include the assessment of vascular disease (including thromboembolic disease) and right upper quadrant pain. Emergency department MR imaging currently has limited availability, and its continued use will require further education regarding operation and image interpretation as well as further validation of cost-effectiveness. Nevertheless, current understanding of the diagnostic utility of this imaging method warrants continued study and the increased use of MR imaging in the evaluation of emergency department patients with acute abdominopelvic pain.

MRI prediction of islet yield for autologous transplantation after total pancreatectomy for chronic pancreatitis.

OBJECTIVE: The relationship between magnetic resonance imaging (MRI), histopathology, and islet yield was examined for chronic pancreatitis patients undergoing total pancreatectomy and autologous islet cell transplant (TP-AIT) to determine if the yield can be predicted by pre-operative MRI. METHODS: MRI sequences and histopathology were scored and compared for patients from whom ≤2,500 islet equivalents/kg were obtained with those from whom >2,500 islet equivalents/kg were obtained. RESULTS: Twenty patients, 14 female, mean age 40.20 ± 12.5 years, (range 19-63) underwent MRI before TP-AIT; mean 3,724 ± 891 islet equivalents/kg body weight, median 2,970, (range 76-17,770) were procured. There was no correlation between islet cell numbers and pancreas weight, HgbA1c, or c-peptide. The most common MRI sequence abnormality was the delayed interstitial phase, 14/18 (78 %). The other common MRI sequence abnormalities were, precontrast T1W 3D GRE sequence, 13/19 (68 %), and the arterial perfusion phase, 11/18 (61 %). The pancreatic duct was dilated in 10/20 (50 %). Parenchymal atrophy was noted in 10/20 (50 %). Median scores for individual MRI sequences were greater in patients with an islet cell yield of ≤2,500 islet equivalents/kg; for the delayed interstitial phase the difference was significant (median 2.5, range 1-3 versus median 0.5, range 0-3, P = 0.034). Histologically the most common feature was fibrosis, (17/17, 100 %); the score for fibrosis was greater for patients with an islet cell yield of ≤2,500 islet equivalents/kg (median 6.0, range 5-7 versus median 4.0, range 3-7, P = 0.024). CONCLUSION: A diminished islet yield may be predicted on the basis of the delayed interstitial phase MRI sequence.

MR imaging of pulmonary embolism: diagnostic accuracy of contrast-enhanced 3D MR pulmonary angiography, contrast-enhanced low-flip angle 3D GRE, and nonenhanced free-induction FISP sequences.

PURPOSE: To evaluate relative detection of pulmonary embolism (PE) with standard bolus-triggered contrast-enhanced breath-hold magnetic resonance (MR) pulmonary angiography, contrast-enhanced recirculation-phase breath-hold low-flip angle three-dimensional (3D) gradient-echo (GRE), and nonenhanced free-induction cardiac- and respiratory-triggered true fast imaging with steady-state precession (FISP) MR sequences. MATERIALS AND METHODS: The study was HIPAA compliant and institutional review board approved. Twenty-two patients with a computed tomographic (CT) angiography diagnosis of PE underwent MR imaging within 48 hours of CT. MR included three complementary techniques: MR pulmonary angiography, 3D GRE, and triggered true FISP. Each sequence was analyzed separately by two independent reviewers who recorded presence of emboli in categorized pulmonary artery anatomic territories. CT angiography results were analyzed by a third independent reviewer, who retrospectively recorded presence of emboli using the same format; these results served as the reference standard. Sensitivity, specificity, and positive and negative predictive values for PE detection were calculated for each MR technique on a per-embolus basis, and 95% confidence intervals were calculated according to the efficient-score method. A two-sample t test was used to compare values among MR techniques. RESULTS: Sensitivities for PE detection were 55% for MR pulmonary angiography, 67% for triggered true FISP, and 73% for 3D GRE MR imaging. Combining all three MR sequences improved overall sensitivity to 84%. Specificity was 100% for all detection methods except for MR pulmonary angiography (one false-positive). Agreement between readers was high (κ = 0.87). Embolus detection rates were lowest in the lingula branch for all MR sequences compared with remainder of the vascular territories (P = .07). CONCLUSION: There are complementary benefits to combining standard MR pulmonary angiography, 3D GRE, and triggered true FISP MR examinations for evaluation of PE.

Liver MRI and histological correlates in chronic liver disease on multiphase gadolinium-enhanced 3D gradient echo imaging.

PURPOSE: To evaluate intrinsic hepatic enhancement patterns on multiphase, gadolinium-enhanced, fat-suppressed, 3D T1-weighted, gradient echo magnetic resonance imaging (MRI) as a quantitative correlate for severity of pathological changes in chronic liver disease (CLD). MATERIALS AND METHODS: This study was HIPAA-compliant and Institutional Review Board-approved. In all, 75 patients were studied by contrast-enhanced multiphase abdominal MRI. CLD patients had liver histology correlation derived from right lobe liver biopsies. Contrast-enhanced arterial- and delayed-phase 3D gradient recalled echo (GRE) liver MRI were scored using feature categorization templates to quantify enhancement patterns by three independent readers. Liver histopathology was staged/graded for fibrosis/inflammation using the Scheuer system. Statistical testing for MRI histology correlates used a Pearson's product moment correlation and a Wilcoxon-Mann-Whitney two-sample rank-sum test. Reader agreement was analyzed by a modified Fleiss' kappa test. RESULTS: MRI histology correlation was high for delayed-phase MRI versus fibrosis stage (95% confidence interval [CI] 0.941 < r < 0.976, P = 5 × 10(-7)), but lower for all other comparisons (delayed-phase vs. inflammation and arterial-phase vs. inflammation or fibrosis all showed a CI no greater than 0.64). Paired testing between delayed-phase MRI score and histology fibrosis staging incremental levels was significant (from P < 10(-2) to P < 10(-5)). CONCLUSION: A standard gadolinium-enhanced liver MRI may provide a correlate measure of hepatic fibrosis over a spectrum of severity.

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

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.