Faculty Bibliography

PURPOSE/OBJECTIVE:To report the quality of gadoxetate disodium MRI in a large series by assessing the prevalence of: 1) arterial phase (AP) artifacts and its predictive factors, 2) decreased hepatic contrast uptake during the hepatobiliary phase (HBP). METHODS:This retrospective single center study included 851 patients (M/F:537/314, mean age: 63y) with gadoxetate disodium MRI. The MRI protocol included unenhanced, dual arterial [early and late arterial phases (AP)], portal venous, transitional and hepatobiliary phases. Three radiologists graded dynamic images using a 5-scale score (1: no motion, 5: severe, nondiagnostic) for assessment of transient severe motion (TSM, defined as a score ≥4 during at least one AP with a score ≤3 during other phases). HBP uptake was assessed using a 3-scale score (based on portal vein/hepatic signal). The association between demographic, clinical and acquisition parameters with TSM was tested in uni- and multivariate logistic regression. RESULTS:TSM was observed in 103/851 patients (12.1 %): 83 (9.8 %) in one AP and 20 (2.3 %) in both APs. A score of 5 (nondiagnostic) was assigned in 7 patients in one AP (0.8 %) and none in both. Presence of TSM was significantly associated with age (p = 0.002) and liver disease (p = 0.033) in univariate but not in multivariate analysis (p > 0.05). No association was found between acquisition parameters and TSM occurrence. Limited or severely limited HBP contrast uptake was observed in 87 patients (10.2 %), and TSM was never associated with severely limited HBP contrast uptake. CONCLUSION/CONCLUSIONS:TSM was present in approximately 12 % of gadoxetate disodium MRIs, rarely on both APs (2.3 %), and was poorly predicted. TSM was never associated with severely limited HBP contrast uptake.

PURPOSE/OBJECTIVE:To assess the diagnostic value of magnetic resonance imaging (MRI)-based radiomics features using machine learning (ML) models in characterizing solid renal neoplasms, in comparison/combination with qualitative radiologic evaluation. METHODS:Retrospective analysis of 125 patients (mean age 59 years, 67% males) with solid renal neoplasms that underwent MRI before surgery. Qualitative (signal and enhancement characteristics) and quantitative radiomics analyses (histogram and texture features) were performed on T2-weighted imaging (WI), T1-WI pre- and post-contrast, and DWI. Mann-Whitney U test and receiver-operating characteristic analysis were used in a training set (n = 88) to evaluate diagnostic performance of qualitative and radiomics features for differentiation of renal cell carcinomas (RCCs) from benign lesions, and characterization of RCC subtypes (clear cell RCC [ccRCC] and papillary RCC [pRCC]). Random forest ML models were developed for discrimination between tumor types on the training set, and validated on an independent set (n = 37). RESULTS:We assessed 104 RCCs (51 ccRCC, 29 pRCC, and 24 other subtypes) and 21 benign lesions in 125 patients. Significant qualitative and quantitative radiomics features (area under the curve [AUC] between 0.62 and 0.90) were included for ML analysis. Models with best diagnostic performance on validation sets showed AUC of 0.73 (confidence interval [CI] 0.5-0.96) for differentiating RCC from benign lesions (using combination of qualitative and radiomics features); AUC of 0.77 (CI 0.62-0.92) for diagnosing ccRCC (using radiomics features), and AUC of 0.74 (CI 0.53-0.95) for diagnosing pRCC (using qualitative features). CONCLUSION/CONCLUSIONS:ML models incorporating MRI-based radiomics features and qualitative radiologic assessment can help characterize renal masses.

Pancreas transplants are an important treatment options for patients with severe diabetes mellitus and other medical conditions. Multiple-imaging modalities, including computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound (US) are available to evaluate the pancreas transplants and their vascular supply, with the graft having a characteristic appearance on each modality. Complications of the graft and its vascular supply present interesting challenges to the clinicians and radiologists caring for this patient population. Being able to identify the imaging appearance of normal and abnormal pancreas transplants, it is necessary to ensure these patients are provided optimal care.

OBJECTIVE:To evaluate the ability of volumetric quantitative apparent diffusion coefficient (ADC) histogram parameters and LI-RADS categorization to distinguish hepatocellular carcinoma (HCC) from other primary liver cancers [intrahepatic cholangiocarcinoma (ICC) and combined HCC-ICC]. METHODS:Sixty-three consecutive patients (44 M/19F; mean age 62 years) with primary liver cancers and pre-treatment MRI including diffusion-weighted imaging (DWI) were included in this IRB-approved single-center retrospective study. Tumor type was categorized pathologically. Qualitative tumor features and LI-RADS categorization were assessed by 2 independent observers. Lesion volume of interest measurements (VOIs) were placed on ADC maps to extract first-order radiomics (histogram) features. ADC histogram metrics and qualitative findings were compared. Binary logistic regression and AUROC were used to assess performance for distinction of HCC from ICC and combined tumors. RESULTS:Sixty-five lesions (HCC, n = 36; ICC, n = 17; and combined tumor, n = 12) were assessed. Only enhancement pattern (p < 0.015) and capsule were useful for tumor diagnosis (p < 0.014). ADC 5th/10th/95th percentiles were significant for discrimination between each tumor types (all p values < 0.05). Accuracy of LI-RADS for HCC diagnosis was 76.9% (p < 0.0001) and 69.2% (p = 0.001) for both observers. The combination of male gender, LI-RADS, and ADC 5th percentile yielded an AUROC/sensitivity/specificity/accuracy of 0.90/79.3%/88.9%/81.5% and 0.89/86.2%/77.8%/80.0% (all p values < 0.027) for the diagnosis of HCC compared to ICC and combined tumors for both observers, respectively. CONCLUSION:The combination of quantitative ADC histogram parameters and LI-RADS categorization yielded the best prediction accuracy for distinction of HCC compared to ICC and combined HCC-ICC.

The canal of Nuck is the female equivalent of the processus vaginalis in the male but is less well known than its male counterpart. It is a rare entity not commonly encountered by radiologists, particularly in the adult population. Knowledge of the embryology and anatomy of the canal of Nuck is essential for identification of the various pathologic conditions that may occur in this location. Moreover, radiologists should be familiar with this entity to compose an appropriate and thorough differential diagnosis of a labial mass/swelling. In this review, we discuss both the anatomy and the more common pathology that can be encountered within it.

OBJECTIVE:Review the multiparametric MRI (mpMRI) findings of transition zone (TZ) prostate cancer (PCa) using T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and dynamic contrast-enhanced (DCE) MRI and to integrate mpMRI findings with clinical history, laboratory values, and histopathology. CONCLUSION:TZ prostate tumors are challenging to detect clinically and at MRI. mpMRI using the combination of sequences has the potential to improve accuracy of TZ cancer detection and staging.

Anorectal disorders are a common cause of presentation to the emergency department (ED). While the most frequently encountered anorectal conditions, such as hemorrhoids and anal fissures, are relatively benign and do not require imaging for diagnosis or management, there are multiple potentially life threatening anorectal conditions for which imaging is an important component of evaluation, diagnosis, and management. Although computed tomography (CT) is the most commonly used imaging modality for evaluation of anorectal pathology in the ED, magnetic resonance imaging (MRI) has an increasingly important role in the detection, characterization and management of specific anorectal conditions. This pictorial essay will review the imaging anatomy of the anorectum, summarize imaging protocols, and discuss the clinical presentation, imaging appearance, and differential diagnosis of anorectal conditions that may present to the emergency department, including infectious, inflammatory, malignant and vascular conditions.

This is a case report of an asymptomatic 4-year-old girl who was found to have a nodule at the lateral left lobe of the liver. She underwent transabdominal liver ultrasound and abdominal MRI that showed calcification and intense arterial enhancement but they failed to clearly exclude malignancy. The patient underwent an unremarkable laparoscopic wedge liver resection of the lesion because of its location and size. Pathological examination showed features compatible with a benign telangiectatic hyperplastic nodule with vascular malformation and calcification. CD34 immunostained the proliferative vascular lining cells while CK7 and CK19 highlighted the normal bile ducts present within the lesion. The diagnosis of a telangiectatic hyperplastic nodule associated with vascular malformation has been scarcely reported in children and our case shows for the first time that it can also present with calcifications.