Faculty Bibliography

OBJECTIVE:To compare the image quality of an accelerated single-shot T2-weighted fat-suppressed (FS) MRI of the liver with deep learning-based image reconstruction (DL HASTE-FS) with conventional T2-weighted FS sequence (conventional T2 FS) at 1.5 T. METHODS:One hundred consecutive patients who underwent clinical MRI of the liver at 1.5 T including the conventional T2-weighted fat-suppressed sequence (T2 FS) and accelerated single-shot T2-weighted MRI of the liver with deep learning-based image reconstruction (DL HASTE-FS) were included. Images were reviewed independently by three blinded observers who used a 5-point confidence scale for multiple measures regarding the artifacts and image quality. Descriptive statistics and McNemar's test were used to compare image quality scores and percentage of lesions detected by each sequence, respectively. Intra-class correlation coefficient (ICC) was used to assess consistency in reader scores. RESULTS:Acquisition time for DL HASTE-FS was 51.23 +/ 10.1 s, significantly (p < 0.001) shorter than conventional T2-FS (178.9 ± 85.3 s). DL HASTE-FS received significantly higher scores than conventional T2-FS for strength and homogeneity of fat suppression; sharpness of liver margin; sharpness of intra-hepatic vessel margin; in-plane and through-plane respiratory motion; other ghosting artefacts; liver-fat contrast; and overall image quality (all, p < 0.0001). DL HASTE-FS also received higher scores for lesion conspicuity and sharpness of lesion margin (all, p < .001), without significant difference for liver lesion contrast (p > 0.05). CONCLUSIONS:Accelerated single-shot T2-weighted MRI of the liver with deep learning-based image reconstruction showed superior image quality compared to the conventional T2-weighted fat-suppressed sequence despite a 4-fold reduction in acquisition time. KEY POINTS/CONCLUSIONS:• Conventional fat-suppressed T2-weighted sequence (conventional T2 FS) can take unacceptably long to acquire and is the most commonly repeated sequence in liver MRI due to motion. • DL HASTE-FS demonstrated superior image quality, improved respiratory motion and other ghosting artefacts, and increased lesion conspicuity with comparable liver-to-lesion contrast compared to conventional T2FS sequence. • DL HASTE- FS has the potential to replace conventional T2 FS sequence in routine clinical MRI of the liver, reducing the scan time, and improving the image quality.

The purpose of this article is to describe arterial and venous thromboembolism in the abdomen, pelvis, and lower extremities. Eight-two COVID patients with abdominal ultrasound or CT were retrospectively compared with non-COVID patients for thromboembolism and solid-organ infarction. Nine (11%) COVID-19 patients had thromboembolic findings with medium to large-sized arterial thrombi in 5/82. One non-COVID patient had known portal vein thrombus on CT. Thromboembolic findings occurred more frequently in patients with than without COVID-19 (p=0.02).

Gender-affirming surgery is becoming more accessible, and radiologists must be familiar with both terminology and anatomy following gender-affirming surgical procedures. This essay will review the most common gender-affirming genital surgeries, their post-operative anatomy, and common complications by providing intraoperative photographs, illustrations, and cross-sectional images. Routine radiologic imaging recommendations for transgender patients will also be reviewed.

OBJECTIVE. The purposes of this study were to evaluate the outcome of new arterial phase enhancing nodules at MRI of cirrhotic livers, including clinical and imaging factors that affect progression to hepatocellular carcinoma (HCC), and to assess the diagnostic performance of Liver Imaging Reporting and Data System version 2018 (LI-RADSv2018) versus version 2017 (LI-RADSv2017) in categorizing these nodules. MATERIALS AND METHODS. A database search identified 129 new arterial phase enhancing, round, solid, space-occupying nodules in 79 patients with cirrhosis who underwent surveillance MRI. Three readers assessed the nodules for LI-RADS findings and made assessments based on the 2017 and 2018 criteria. Clinical information and laboratory values were collected. Outcome data were assessed on the basis of follow-up imaging and pathology results. Interreader agreement was assessed. Logistic regression and ROC curve analyses were used to assess the utility of the features for prediction of progression to HCC. RESULTS. Of the 129 nodules, 71 (55%) progressed to HCC. LI-RADSv2017 score, LIRADSv2018 score, and mild-to-moderate T2 hyperintensity were significant independent predictors of progression to HCC in univariate analyses. Serum α-fetoprotein level, hepatitis B or C virus infection as the cause of liver disease, and presence of other HCCs were significant predictors of progression to HCC in multivariate analyses. The rates of progression of LI-RADS category 3 and 4 observations were 38.1% and 57.6%, respectively, for LI-RADSv2017 and 44.4% and 69.9%, respectively, for LI-RADSv2018. CONCLUSION. New arterial phase enhancing nodules in patients with cirrhosis frequently progress to HCC. Factors such as serum α-fetoprotein level and presence of other HCCs are strong predictors of progression to HCC.

OBJECTIVE. The objective of this article is to assess radiologist concordance in characterizing thyroid nodules using the American College of Radiology Thyroid Imaging Reporting and Data System (TI-RADS), focusing on the effect of radiologist experience on reader concordance. MATERIALS AND METHODS. Three experienced and three less experienced radiologists assessed 150 thyroid nodules using the TI-RADS lexicon. Percent concordance was determined for various endpoints. RESULTS. Interreader concordance for the five TI-RADS categories was 87.2% for shape, 81.2% for composition, 76.1% for echogenicity, 72.9% for margins, and 69.8% for echogenic foci. Concordance for individual features was 96.3% for rim calcifications, 90.8% for macrocalcifications, 90.1% for spongiform, 83.5% for comet tail artifact, and 77.7% for punctate echogenic foci. Concordance for the TI-RADS level and recommendation for fine-needle aspiration (FNA) were 50.4% and 78.9%, respectively. Concordance was significantly (p < 0.05) higher for less experienced readers in identifying margins (84.3% vs 67.4%), echogenic foci (76.9% vs 69.3%), comet tail artifact (89.6% vs 79.2%), and punctate echogenic foci (85.3% vs 75.5%), and lower for peripheral rim calcifications (95.0% vs 97.8 %), but was not different (p > 0.05) for the remaining categories and features. CONCLUSION. A range of TI-RADS categories, features, and recommendations for FNA had generally moderate interreader agreement among six radiologists. Our results show that concordance for numerous characteristics was significantly higher for the less experienced versus the more experienced readers. These results suggest that less experienced readers relied more on the explicit TI-RADS criteria, whereas the experienced radiologists partially relied on their accumulated experience when forming impressions. However, the overall TI-RADS level and recommendation for FNA were unaffected, supporting the robustness of the TI-RADS lexicon and its continued use in practice.

RATIONALE AND OBJECTIVES: To assess the American College of Radiology Incidental Findings Committee's (ACR-IFC) recommendations for defining and following up abnormal incidental abdominopelvic lymph nodes. MATERIALS AND METHODS: A total of 59 lymph nodes satisfying ACR-IFC criteria as incidental (no malignancy or lymphoproliferative disorder) and with sufficient follow-up to classify as benign (biopsy, decreased size, >/=12-month stability) or malignant (biopsy, detection of primary malignancy combined with either fluorodeoxyglucose hyperactivity or increase in size of the node) were included. Two radiologists independently assessed nodes for suspicious features by ACR-IFC criteria (round with indistinct hilum, hypervascularity, necrosis, cluster >/=3 nodes, cluster >/=2 nodes in >/=2 stations, size >/=1 cm in retroperitoneum). Outcomes were assessed with attention to ACR-IFC's recommendation for initial 3-month follow-up. RESULTS: A total of 8.5% of nodes were malignant; 91.5% were benign. Two of six malignant nodes were stable at 3 to <6-month follow-up before diagnosis; diagnosis of four of five malignant nodes was facilitated by later development of non-nodal sites of tumor. A total of 13, 5, 8, and 9 nodes were deemed benign given a decrease at <3 months, 3-5 months, 6-11 months, or >/=12 months of follow-up. No ACR-IFC feature differentiated benign and malignant nodes (P = 0.164-1.0). A cluster >/=3 nodes was present in 88.1%-93.2% of nodes. A total of 96.6%-98.3% had >/=1 suspicious feature for both readers. Necrosis and hypervascularity were not identified in any node. CONCLUSIONS: ACR-IFC imaging features overwhelmingly classified incidental nodes as abnormal, although did not differentiate benign and malignant nodes. Nodes stable at the ACR-IFC's advised initial 3-month follow-up were occasionally proven malignant or decreased on further imaging. Refinement of imaging criteria to define nodes of particularly high risk, integrated with other clinical criteria, may help optimize the follow-up of incidental abdominopelvic lymph nodes.

OBJECTIVE: The purpose of this study is to evaluate the roles of self-directed learning and continual feedback in the learning curve for tumor detection by novice readers of prostate MRI. MATERIALS AND METHODS: A total of 124 prostate MRI examinations classified as positive (n = 52; single Prostate Imaging Reporting and Data System [PI-RADS] category 3 or higher lesion showing Gleason score >/= 7 tumor at MRI-targeted biopsy) or negative (n = 72; PI-RADS category 2 or lower and negative biopsy) for detectable tumor were included. These were divided into four equal-sized batches, each with matching numbers of positive and negative examinations. Six second-year radiology residents reviewed examinations to localize tumors. Three of the six readers received feedback after each examination showing the preceding case's solution. The learning curve, plotting accuracy over time, was assessed by the Akaike information criterion (AIC). Logistic regression and mixed-model ANOVA were performed. RESULTS: For readers with and without feedback, the learning curve exhibited an initial rapid improvement that slowed after 40 examinations (change in AIC > 0.2%). Accuracy improved from 58.1% (batch 1) to 71.0-75.3% (batches 2-4) without feedback and from 58.1% to 72.0-77.4% with feedback (p = 0.027-0.046), without a difference in the extent of improvement (p = 0.800). Specificity improved from 53.7% to 68.5-81.5% without feedback and from 55.6% to 74.1-81.5% with feedback (p = 0.006-0.010), without a difference in the extent of improvement (p = 0.891). Sensitivity improved from 59.0-61.5% (batches 1-2) to 71.8-76.9% (batches 3-4) with feedback (p = 0.052), though did not improve without feedback (p = 0.602). Sensitivity for transition zone tumors exhibited larger changes (p = 0.024) with feedback than without feedback. Sensitivity for peripheral zone tumors did not improve in either group (p > 0.3). Reader confidence increased only with feedback (p < 0.001). CONCLUSION: The learning curve in prostate tumor detection largely reflected self-directed learning. Continual feedback had a lesser effect. Clinical prostate MRI interpretation by novice radiologists warrants caution.

BACKGROUND: Common variable immunodeficiency (CVID) is a heterogeneous disorder commonly presenting with recurrent sinopulmonary infections. In all, 6%-10% of CVID patients develop an inflammatory bowel disease (IBD)-like disorder, making these patients a unique population to investigate immune-mediated gastrointestinal disease. This study examined whether defects in peripheral and/or intestinal lymphocytes are involved in disruption of the intestinal mucosa in CVID patients with inflammatory intestinal diseases. METHODS: Peripheral blood (PB) T cells from healthy controls; CD or UC; CVID; and CVID with IBD were stimulated for 48 hours with anti-CD3+CD28 or phytohemagglutinin (PHA) + phorbol 12-myristate 13-acetate (PMA); cytokine production was measured by enzyme-linked immunosorbent assay (ELISA). Cytokine expression from unstimulated lamina propria lymphocytes (LPLs) was compared by real-time polymerase chain reaction (PCR). Immunohistochemistry of mucosal biopsies was performed. Cell populations were quantified by morphometry. RESULTS: CVID/IBD PB T cells stimulated by anti-CD3+CD28 had trends for reduced IL-2, IL-10, IFN-gamma, and TNF-alpha compared to controls. These differences were not apparent following stimulation by PHA/PMA. Constitutive production of inflammatory cytokines by LPLs was not detected. Histologically, CVID patients had reduced/absent plasma cells with reductions in intestinal IgM and IgA. CVID patients with and without gastrointestinal (GI) disease exhibited increased CD3+ T cells, specifically CD8+, in the colon compared to normal and IBD controls, suggesting immune dysregulation. CONCLUSIONS: Intestinal inflammation in CVID patients with IBD-like disease may be mediated by abnormal cytokine production through a T-cell receptor-mediated pathway. However, the variability observed suggests multiple, rather than singular, mechanisms are involved. Histologic features such as reduced intestinal plasma cells and lack of intestinal immunoglobulins may be useful markers in diagnosing CVID in a patient with GI disease refractory to conventional therapies.