Uterine Sarcoma or Degenerating Fibroid? Validating the New Consensus Magnetic Resonance Imaging Algorithm for Evaluating Atypical Uterine Masses.

OBJECTIVE: The aim of the study is to assess the validity of a recently published consensus magnetic resonance imaging (MRI) diagnostic algorithm for differentiating degenerating leiomyomas from uterine sarcomas and other atypical appearing uterine malignancies. METHODS: Atypical uterine masses on pelvic MRI were identified using a radiology report search engine and teaching files with the keywords "atypical leiomyoma," "atypical fibroid," and "sarcoma." All cases were pathology-proven. Two radiologists blinded to clinical, surgical, and pathologic reports retrospectively and independently reviewed 40 pelvic MRI examinations dated 1/2007-9/2022 to determine whether the masses appeared benign or malignant, using the 2022 consensus atypical uterine mass flow chart. Imaging features assessed included intermediate/high signal intensity (SI) at T2-weighted imaging, high diffusion weighted imaging SI (equal or higher SI than endometrium or lymph nodes on high b value imaging), apparent diffusion coefficient (ADC) value ≤0.905 × 10-3 mm2/s, peritoneal metastases, and abnormal lymph nodes. RESULTS: Among the 40 atypical uterine mass cases reviewed, 24 masses were benign (22 leiomyomas, 1 adenomyoma, and 1 borderline ovarian tumor) and 16 masses were malignant (6 leiomyosarcomas, 6 carcinosarcomas, 2 endometrial stromal sarcomas, 1 high-grade adenosarcoma, and 1 low-grade uterine sarcoma). Sensitivity, specificity, positive predictive value, and negative predictive value of whether a mass was benign or malignant were 75%, 95.8%, 92.3%, and 85% for reader 1, and 81.2%, 91.7%, 86.7%, and 88% for reader 2, respectively. Interrater agreement was strong, with a kappa statistic of 0.89. When excluding nonleiomyosarcoma uterine malignancies, sensitivity and negative predictive value improved to 100%. CONCLUSIONS: The new consensus pelvic MRI algorithm for evaluating atypical uterine masses has good specificity, sensitivity, positive predictive value, and negative predictive value for determining malignancy, particularly for uterine sarcomas that are leiomyosarcomas. However, if ADC value is near but not below 0.905 × 10-3 mm2/s, the mass may still be malignant, especially if a b value lower than 1000 is used. If the atypical uterine mass is predominantly endometrial, morphological features on T2 and postgadolinium sequences should guide suspicion, as some atypical appearing nonleiomyosarcoma uterine malignancies may have an ADC value greater than 0.905 × 10-3 mm2/s.

Benign pericholecystic regeneration mimicking hepatocellular carcinoma: a potential pitfall in imaging of cirrhosis.

Several pseudolesions mimicking malignancy have been reported in cirrhotic and non-cirrhotic livers. Pericholecystic regeneration is among those pseudolesions and can occasionally mimic malignancy. Herein we present a case series comprised of 10 cirrhotic patients (majority due to alcoholic liver disease [ALD] or metabolic dysfunction associated steatotic liver disease [MASLD]) with pericholecystic observations initially categorized as highly suspicious for HCC (LR-4 and LR-5) due to their suspicious enhancement pattern which were later proven to be benign based on biopsy, transplantation or imaging criteria (stability of size and morphology on serial CT or MRI for > 2 years). These observations ranged 2-6.3 cm in size, were multiple in most patients and universally resulted in indentations of gallbladder. Arterial phase hyperenhancement and washout, features usually attributed to hepatocellular carcinoma (HCC), were seen in most patients. However, ancillary features of malignancy such as diffusion restriction, increased T2 signal, and hypointensity on hepatobiliary phase MRI were not present. Pericholecystic observations, in particular in the setting of ALD and MASLD, should be carefully assessed and possibility of pseudolesion should be considered especially when the observations are multiple, cause indentation of gallbladder, and lack ancillary features of malignancy.

Hepatic Sinusoidal Disorders.

Hepatic sinusoids are highly specialized microcirculatory conduits within the hepatic lobules that facilitate liver functions. The sinusoids can be affected by various disorders, including sinusoidal dilatation, sinusoidal obstruction syndrome (SOS), sinusoidal cellular infiltration, perisinusoidal infiltration, and endothelial neoplasms, such as hemangioendothelioma and angiosarcoma. While these disorders, particularly SOS and neoplasms, can be life threatening, their clinical manifestation is often nonspecific. Patients may present with right upper quadrant pain, jaundice, hepatomegaly, ascites, splenomegaly, and unexplained weight gain, although the exact manifestation depends on the cause, severity, and duration of the disease. Ultimately, invasive tests may be necessary to establish the diagnosis. A comprehensive understanding of imaging manifestations of various sinusoidal disorders contributes to early diagnosis and can help radiologists detect subclinical disease. Additionally, specific imaging features may assist in identifying the cause of the disorder, leading to a more focused and quicker workup. For example, a mosaic pattern of enhancement of the liver parenchyma is suggestive of sinusoidal dilatation; peripheral and patchy reticular hypointensity of the liver parenchyma on hepatobiliary MR images is characteristic of SOS; and associated diffuse multiple hyperintensities on diffusion-weighted images may be specific for malignant sinusoidal cellular infiltration. The authors provide an overview of the pathogenesis, clinical features, and imaging appearances of various hepatic sinusoidal disorders, with a special emphasis on SOS. ©RSNA, 2024 Supplemental material is available for this article.

Imaging of Biliary Tree Abnormalities.

Pathologic conditions of the biliary system, although common, can be difficult to diagnose clinically. Challenges in biliary imaging include anatomic variants and the dynamic nature of the biliary tract, which can change with age and intervention, blurring the boundaries of normal and abnormal. Choledochal cysts can have numerous appearances and are important to diagnose given the risk of cholangiocarcinoma potentially requiring surgical resection. Choledocholithiasis, the most common cause of biliary dilatation, can be difficult to detect at US and CT, with MRI having the highest sensitivity. However, knowledge of the imaging pitfalls of MRI and MR cholangiopancreatography is crucial to avoid misinterpretation. Newer concepts in biliary tract malignancy include intraductal papillary biliary neoplasms that may develop into cholangiocarcinoma. New paradigms in the classification of cholangiocarcinoma correspond to the wide range of imaging appearances of the disease and have implications for prognosis. Accurately staging cholangiocarcinoma is imperative, given expanding curative options including transplant and more aggressive surgical options. Infections of the biliary tree include acute cholangitis or recurrent pyogenic cholangitis, characterized by obstruction, strictures, and central biliary dilatation. Inflammatory conditions include primary sclerosing cholangitis, which features strictures and fibrosis but can be difficult to differentiate from secondary causes of sclerosing cholangitis, including more recently described entities such as immunoglobulin G4-related sclerosing cholangitis and COVID-19 secondary sclerosing cholangitis. The authors describe a wide variety of benign and malignant biliary tract abnormalities, highlight differentiating features of the cholangitides, provide an approach to interpretation based on the pattern of imaging findings, and discuss pearls and pitfalls of imaging to facilitate accurate diagnosis. ©RSNA, 2024 Supplemental material is available for this article.

Imaging of pancreatic serous cystadenoma and common imitators.

Pancreatic cystic neoplasms are lesions comprised of cystic components that show different biological behaviors, epidemiology, clinical manifestations, imaging features, and malignant potential and management. Benign cystic neoplasms include serous cystic neoplasms (SCAs). Other pancreatic cystic lesions have malignant potential, such as intraductal papillary mucinous neoplasms and mucinous cystic neoplasms. SCAs can be divided into microcystic (classic appearance), honeycomb, oligocystic/macrocystic, and solid patterns based on imaging appearance. They are usually solitary but may be multiple in von Hippel-Lindau disease, which may depict disseminated involvement. The variable appearances of SCAs can mimic other types of pancreatic cystic lesions, and cross-sectional imaging plays an important role in their differential diagnosis. Endoscopic ultrasonography has helped in improving diagnostic accuracy of pancreatic cystic lesions by guiding tissue sampling (biopsy) or cyst fluid analysis. Immunohistochemistry and newer techniques such as radiomics have shown improved performance for preoperatively discriminating SCAs and their mimickers.

Imaging cholangiocarcinoma: CT and MRI techniques.

Cross-sectional imaging plays a crucial role in the detection, diagnosis, staging, and resectability assessment of intra- and extrahepatic cholangiocarcinoma. Despite this vital function, there is a lack of standardized CT and MRI protocol recommendations for imaging cholangiocarcinoma, with substantial differences in image acquisition across institutions and vendor platforms. In this review, we present standardized strategies for the optimal imaging assessment of cholangiocarcinoma including contrast media considerations, patient preparation recommendations, optimal contrast timing, and representative CT and MRI protocols with individual sequence optimization recommendations. Our recommendations are supported by expert opinion from members of the Society of Abdominal Radiology's Disease-Focused Panel (DFP) on Cholangiocarcinoma, encompassing a broad array of institutions and practice patterns.

Detection of moderate hepatic steatosis on contrast-enhanced dual-source dual-energy CT: Role and accuracy of virtual non-contrast CT.

PURPOSE: To investigate diagnostic accuracy of virtual non contrast (VNC) images, based on dual-source dual-energy CT (dsDECT), for detection of at least moderate steatosis and to define a threshold value to make this diagnosis on VNC. METHODS: This single-institution retrospective study included patients who had multi-phasic protocol dsDECT. Regions of interests were placed in different segments of the liver and spleen on true non-contrast (TNC), VNC, and portal-venous phase (PVP) images. At least moderate steatosis was defined as liver attenuation (LHU) < 40 HU on TNC. Diagnostic performance of VNC to detect steatosis was determined and the new threshold was tested in a validation cohort. RESULTS: 236 patients were included in training cohort. Mean liver attenuation values were 51.3 ±â€¯10.8 HU and 58.1 ±â€¯11.5 HU for TNC and VNC (p < 0.001), with a mean difference (VNC - TNC) of 6.8 ±â€¯6.9 HU. Correlation between TNC and VNC was strong (r = 0.81, p < 0.001). The AUCs of LHU on VNC for detection of hepatic steatosis were 0.92 (95 % Cl: 0.86-0.98), 0.92 (95 % Cl: 0.87-0.97), 0.92 (95 % Cl: 0.86-0.99), 0.91 (95 % Cl: 0.84-0.97), and 0.87 (95 % Cl: 0.80-0.95) for entire liver, left lateral, left medial, right anterior, and right posterior segments, respectively. VNC had sensitivity/specificity of 100 % /42 % when using a threshold of 40 HU; they were 69 % and 95 %, respectively, when using optimized threshold of 46 HU. This threshold showed similar performance in validation cohort (n = 80). CONCLUSIONS: Hepatic attenuation on VNC has promising performance for detection of at least moderate steatosis. Proposed threshold of 46 HU provides high specificity and moderate sensitivity to detect steatosis.

Evaluation of 18 CT signs in diagnosing cecal volvulus: a multi-reader retrospective study.

PURPOSE: To assess the diagnostic performance and reliability of 18 CT signs to diagnose cecal volvulus, a surgical emergency, versus a group of non-volvulus mimickers. MATERIALS AND METHODS: Four radiologists retrospectively and independently assessed 18 CT signs in 191 patients with cecal volvulus (n = 63) or a non-volvulus control group ((n = 128), including cecal bascule (n = 19), mobile cecum (n = 95), and colonic pseudo-obstruction (n = 14)) at a single institution from 2013 to 2021. Fleiss' kappa coefficient was used to assess inter-reader agreement. For diagnostic performance metrics, we assessed sensitivity, specificity, and positive and negative predictive values. For predictive performance, all 18 signs were included in bivariate and stepwise lasso multivariate logistic regression models to diagnose cecal volvulus. Performance was assessed by ROC curves. RESULTS: 191 patients (mean age: 63 years +/- 15.5 [SD]; 135 women) were included in the study. Nine of the 18 CT signs of cecal volvulus demonstrated good or better (> 0.6) inter-reader agreement. Individual CT signs with sensitivity, specificity, positive and negative predictive values all above 70% for diagnosing cecal volvulus were transition point, bird beak, and X-marks-the-spot. A lasso regression model determined four CT features: transition point, bird beak, coffee bean, and whirl had excellent prediction (AUC = .979) for cecal volvulus if all present. CONCLUSION: CT signs for cecal volvulus that have high sensitivity and specificity include: transition point, bird beak, and X-marks-the-spot and were reliable in distinguishing non-volvulus mimickers. If the following four features were present: transition point, bird beak, coffee bean, and whirl, there was excellent prediction (AUC = .979) for cecal volvulus.

Pancreatic Cancer and Its Mimics.

Pancreatic ductal adenocarcinoma (PDAC) is the most common primary pancreatic malignancy, ranking fourth in cancer-related mortality in the United States. Typically, PDAC appears on images as a hypovascular mass with upstream pancreatic duct dilatation and abrupt duct cutoff, distal pancreatic atrophy, and vascular encasement, with metastatic involvement including lymphadenopathy. However, atypical manifestations that may limit detection of the underlying PDAC may also occur. Atypical PDAC features include findings related to associated conditions such as acute or chronic pancreatitis, a mass that is isointense to the parenchyma, multiplicity, diffuse tumor infiltration, associated calcifications, and cystic components. Several neoplastic and inflammatory conditions can mimic PDAC, such as paraduodenal "groove" pancreatitis, autoimmune pancreatitis, focal acute and chronic pancreatitis, neuroendocrine tumors, solid pseudopapillary neoplasms, metastases, and lymphoma. Differentiation of these conditions from PDAC can be challenging due to overlapping CT and MRI features; however, certain findings can help in differentiation. Diffusion-weighted MRI can be helpful but also can be nonspecific. Accurate diagnosis is pivotal for guiding therapeutic planning and potential outcomes in PDAC and avoiding biopsy or surgical treatment of some of these mimics. Biopsy may still be required for diagnosis in some cases. The authors describe the typical and atypical imaging findings of PDAC and features that may help to differentiate PDAC from its mimics. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center. See the invited commentary by Zins in this issue.

Liver Fibrosis, Fat, and Iron Evaluation with MRI and Fibrosis and Fat Evaluation with US: A Practical Guide for Radiologists.

Quantitative imaging biomarkers of liver disease measured by using MRI and US are emerging as important clinical tools in the management of patients with chronic liver disease (CLD). Because of their high accuracy and noninvasive nature, in many cases, these techniques have replaced liver biopsy for the diagnosis, quantitative staging, and treatment monitoring of patients with CLD. The most commonly evaluated imaging biomarkers are surrogates for liver fibrosis, fat, and iron. MR elastography is now routinely performed to evaluate for liver fibrosis and typically combined with MRI-based liver fat and iron quantification to exclude or grade hepatic steatosis and iron overload, respectively. US elastography is also widely performed to evaluate for liver fibrosis and has the advantage of lower equipment cost and greater availability compared with those of MRI. Emerging US fat quantification methods can be performed along with US elastography. The author group, consisting of members of the Society of Abdominal Radiology (SAR) Liver Fibrosis Disease-Focused Panel (DFP), the SAR Hepatic Iron Overload DFP, and the European Society of Radiology, review the basics of liver fibrosis, fat, and iron quantification with MRI and liver fibrosis and fat quantification with US. The authors cover technical requirements, typical case display, quality control and proper measurement technique and case interpretation guidelines, pitfalls, and confounding factors. The authors aim to provide a practical guide for radiologists interpreting these examinations. © RSNA, 2023 See the invited commentary by Ronot in this issue. Quiz questions for this article are available in the supplemental material.

Chemical Shift MRI Monitoring of Chemoembolization Delivery for Hepatocellular Carcinoma: Multicenter Feasibility of Initial Clinical Translation.

Purpose To demonstrate the feasibility of using chemical shift fat-water MRI methods to visualize and measure intrahepatic delivery of ethiodized oil to liver tumors following conventional transarterial chemoembolization (cTACE). Materials and Methods Twenty-eight participants (mean age, 66 years ± 8 [SD]; 22 men) with hepatocellular carcinoma (HCC) treated with cTACE were evaluated with follow-up chemical shift MRI in this Health Insurance Portability and Accountability Act-compliant prospective, institutional review board-approved study. Uptake of ethiodized oil was evaluated at 1-month follow-up chemical shift MRI. Measurements of tumor size (MRI and CT), attenuation and enhancement (CT), fat content percentage, and tumor:normal ratio (MRI) were compared by lesion for responders versus nonresponders, as assessed with modified Response Evaluation Criteria in Solid Tumors and European Association for the Study of the Liver (EASL) criteria. Adverse events and overall survival by the Kaplan-Meier method were secondary end points. Results Focal tumor ethiodized oil retention was 46% (12 of 26 tumors) at 24 hours and 47% (18 of 38 tumors) at 1 month after cTACE. Tumor volume at CT did not differ between EASL-defined responders and nonresponders (P = .06). Tumor ethiodized oil volume measured with chemical shift MRI was statistically significantly higher for EASL-defined nonresponders (P = .02). Doxorubicin dosing (P = .53), presence of focal fat (P = .83), and a combined end point of focal fat and low doxorubicin dosing (P = .97) did not stratify overall survival after cTACE. Conclusion Chemical shift MRI allowed for assessment of tumor delivery of ethiodized oil out to 1 month after cTACE in participants with HCC and demonstrated tumor ethiodized oil volume as a potential tool for stratification of tumor response by EASL criteria. Keywords: MRI, Chemical Shift Imaging, CT, Hepatic Chemoembolization, Ethiodized Oil Clinicaltrials.gov registration no.: NCT02173119 Supplemental material is available for this article. © RSNA, 2023.

Gamut of Extratesticular Scrotal Masses: Anatomic Approach to Sonographic Differential Diagnosis.

The commonly taught tenet that intratesticular lesions are always malignant and extratesticular scrotal lesions are always benign is a simplistic statement that erroneously minimizes the significance of extratesticular scrotal masses and their diagnosis. Yet, disease in the extratesticular space is commonly encountered by clinicians and radiologists and is often a source of uncertainty in diagnosis and management. Given the embryologically rooted complex anatomy of this region, a wide range of pathologic conditions is possible. Radiologists may not be familiar with some of these conditions; further, many of these lesions can have a specific sonographic appearance, allowing accurate diagnosis that can minimize surgical intervention. Lastly, malignancies can occur in the extratesticular space-although this is less common than in the testicles-and proper recognition of findings that warrant additional imaging or surgery is critical in optimizing outcomes. The authors present a compartmental anatomic framework for differential diagnosis of extratesticular scrotal masses and provide a comprehensive illustrative display of many of the pathologic conditions that can be encountered to familiarize radiologists with the sonographic appearances of these lesions. They also review management of these lesions and scenarios where US may not be definitive in diagnosis and selective use of scrotal MRI can be helpful. © RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Accumulation of iodine or other similar K-edge equivalent element within renal cysts mimics enhancing masses at single-phase dual-energy CT.

OBJECTIVE: To describe instances of iodine, or other element with similar K-edge to iodine, accumulating in benign renal cysts and simulating solid renal masses (SRM) at single-phase contrast-enhanced (CE) dual-energy CT (DECT). METHODS: During the course of routine clinical practice, instances of benign renal cysts (reference standard true non-contrast enhanced CT [NCCT] homogeneous attenuation <10 HU and not enhancing, or MRI) simulating SRM at follow-up single-phase CE-DECT due to iodine (or other element) accumulation were documented in two institutions over a 3-month observation period in 2021. RESULTS: Five Bosniak one renal cysts (12 ± 7 mm) in five patients changed nature on follow-up imaging simulating SRM at CE-DECT. At time of DECT, cyst attenuation on true NCCT (mean 91 ± 25 HU [Range 56-120]) was significantly higher compared to virtual NCCT (mean 11 ± 22 HU [-23-30], p = 0.003) and all five cysts showed internal iodine content on DECT iodine maps with concentration >1.9 mg ml-1 (mean 8.2 ± 7.6 mg ml-1 [2.8-20.9]). CONCLUSION: The accumulation of iodine, or other element with similar K-edge to iodine, in benign renal cysts could simulate enhancing renal masses at single-phase contrast-enhanced DECT.

The Society of Abdominal Radiology at 10 years: Reflections, status report, and look to the future.

In 2012, the Society of Abdominal Radiology (SAR) was formed by the merger of the Society of Gastrointestinal Radiologists (SGR) and the Society of Uroradiology (SUR). On the occasion of SAR's ten year anniversary, this commentary describes important changes in society structure, the growth and diversity of society membership, new educational and research initiatives, intersociety and international outreach, and plans for the future.

Optional MRI sequences for LI-RADS: why, what, and how?

Hepatocellular carcinoma (HCC) is the most common primary malignant tumor of the liver worldwide. Noninvasive diagnosis of HCC is possible based on imaging features, without the need for tissue diagnosis. Liver Imaging Reporting and Data System (LI-RADS) CT/MRI diagnostic algorithm allows for standardized radiological interpretation and reporting of imaging studies for patients at high risk for HCC. Diagnostic categories of LR-1 to LR-5 designate each liver observation to reflect the probability of overall malignancy, HCC, or benignity based on imaging features, where LR-5 category has > 95% probability of HCC. Optimal imaging protocol and scanning technique as described by the technical recommendations for LI-RADS are essential for the depiction of features to accurately characterize liver observations. The LI-RADS MRI technical guidelines recommend the minimum required sequences of T1-weighted out-of-phase and in-phase Imaging, T2-weighted Imaging, and multiphase T1-weighted Imaging. Additional sequences, including diffusion-weighted imaging, subtraction imaging, and the hepatobiliary phase when using gadobenate dimeglumine as contrast, improve diagnostic confidence, but are not required by the guidelines. These optional sequences can help differentiate true lesions from pseudolesions, detect additional observations, identify parenchymal observations when other sequences are suboptimal, and improve observations conspicuity. This manuscript reviews the optional sequences, the advantages they offer, and discusses technical optimization of these sequences to obtain the highest image quality and to avoid common artifacts.

"Imaging Findings of Eosinophilic Gastrointestinal Diseases in Adults".

Eosinophilic gastrointestinal (GI) disorders are a group of conditions marked by pathologic eosinophilic infiltration of one or multiple locations in the GI tract. Conditions include eosinophilic esophagitis, eosinophilic gastritis, eosinophilic enteritis, and eosinophilic colitis. The site and depth of eosinophilic infiltration of the GI tract usually determines clinical presentation. These conditions should be considered in the differential diagnosis for several GI symptoms, such as food impaction or dysphagia. Histopathology is the gold standard for diagnosis of eosinophilic disorders. Nevertheless, findings from endoscopy, barium studies, computed tomography or magnetic resonance imaging, can aid in the diagnosis, by allowing for earlier diagnosis as well as proper management. Eosinophilic gastrointestinal disorders are typically managed with corticosteroids or dietary elimination. A high index of suspicion is required for diagnosis as it can often be challenging.

MRI features associated with HCC histologic subtypes: a western American and European bicenter study.

OBJECTIVES: To evaluate if preoperative MRI can predict the most frequent HCC subtypes in North American and European patients treated with surgical resection. METHODS: A total of 119 HCCs in 97 patients were included in the North American group and 191 HCCs in 176 patients were included in the European group. Lesion subtyping was based on morphologic features and immuno-histopathological analysis. Two radiologists reviewed preoperative MRI and evaluated the presence of imaging features including LI-RADS major and ancillary features to identify clinical, biologic, and imaging features associated with the main HCC subtypes. RESULTS: Sixty-four percent of HCCs were conventional. The most frequent subtypes were macrotrabecular-massive (MTM-15%) and steatohepatitic (13%). Necrosis (OR = 3.32; 95% CI: 1.39, 7.89; p = .0064) and observation size (OR = 1.011; 95% CI: 1.0022, 1.019; p = .014) were independent predictors of MTM-HCC. Fat in mass (OR = 15.07; 95% CI: 6.57, 34.57; p < .0001), tumor size (OR = 0.97; 95% CI: 0.96, 0.99; p = .0037), and absence of chronic HCV infection (OR = 0.24; 95% CI: 0.084, 0.67; p = .0068) were independent predictors of steatohepatitic HCC. Independent predictors of conventional HCCs were viral C hepatitis (OR = 3.20; 95% CI: 1.62, 6.34; p = .0008), absence of fat (OR = 0.25; 95% CI: 0.12, 0.52; p = .0002), absence of tumor in vein (OR = 0.34; 95% CI: 0.13, 0.84; p = .020), and higher tumor-to-liver ADC ratio (OR = 1.96; 95% CI: 1.14, 3.35; p = .014) CONCLUSION: MRI is useful in predicting the most frequent HCC subtypes even in cohorts with different distributions of liver disease etiologies and tumor subtypes which might have future treatment and management implications. KEY POINTS: • Representation of both liver disease etiologies and HCC subtypes differed between the North American and European cohorts of patients. • Retrospective two-center study showed that liver MRI is useful in predicting the most frequent HCC subtypes.

Utilizing CT to identify clinically significant biliary dilatation in symptomatic post-cholecystectomy patients: when should we be worried?

PURPOSE: To determine a reliable threshold common duct diameter on CT, in combination with other ancillary CT and clinical parameters, at which the likelihood of pathology requiring further imaging or intervention is increased in post-cholecystectomy patients. METHODS: In this IRB approved retrospective study, two attending radiologists independently reviewed CT imaging for 118 post-cholecystectomy patients, who were subsequently evaluated with MRCP, ERCP, or EUS, prompted by findings on the CT and clinical status. Measurements of the common duct (CD) were obtained at the porta hepatis, distal duct, and point of maximal dilation on axial and coronal CT scans. Patients were grouped by whether they required intervention after follow-up imaging. Pertinent baseline lab values and patient demographics were reviewed. RESULTS: Of the 118 post-cholecystectomy patients, 38 patients (31%) required intervention, and 80 patients (69%) did not require intervention after follow-up imaging. For both readers, axial and coronal CD diameters were significantly higher in the 'intervention required' vs 'no intervention' groups at all locations (p value < 0.05). There was good to excellent inter-reader agreement at all locations (ICC 0.68-0.92). Pertinent baseline lab values including AST (p = 0.043), ALT (p = 0.001), alkaline phosphatase (p = 0.0001), direct bilirubin (p = 0.011), total bilirubin (p = 0.028), and WBC (p = 0.043) were significantly higher in the 'intervention required' group. CD thresholds of 8 mm yielded the highest sensitivities (76-95%), and CD thresholds of 12 mm yielded the highest specificities (65-78%). CD combined with bilirubin levels increased sensitivity and specificity, compared to using either feature alone. CONCLUSION: Dilated CD on CT combined with bilirubin levels increases the sensitivity and specificity for identifying patients needing intervention. We recommend that a post-cholecystectomy patient who presents with a CD diameter > 10 mm on CT and elevated bilirubin levels should undergo further clinical and imaging follow-up.