Direct sac puncture versus transarterial embolization of type II endoleaks after endovascular abdominal aortic aneurysm repair: Comparison of outcomes.

PURPOSE: Type 2 endoleak (T2EL) is the most common type of endoleak after endovascular abdominal aortic aneurysm repair (EVAR), and increases the risk of aneurysm sac rupture if it persists beyond 6 months. The purpose of this study is to compare the efficacy and safety of direct sac puncture versus transarterial embolization of T2ELs. METHODS: Retrospective review of 42 consecutive T2EL embolization procedures, 19 by DSP and 23 by transarterial technique, between January 2015 and December 2020. Primary outcome was aneurysm sac stability and resolution of endoleak at follow-up imaging. Adverse events (AE) were classified based on the Society of Interventional Radiology (SIR) practice guidelines. RESULTS: Technical success was 94.7% (18/19) in the DSP group and 86.9% (20/23) in the transarterial group (p = 0.32 (-0.77-0.25)). Treatment efficacy was evaluated in 16 patients in the DSP group and 18 patients in the transarterial group who had follow-up imaging ≥6 months after embolization. Mean imaging follow-up was 17.1 ± 11.2 (range, 6-41) months in the DSP group and 26.5 ± 15.4 (range, 6-48) months in the transarterial group (p = 0.06, -19.24-0.37). Treatment efficacy was 75% (12/16) in the DSP group and 33.3% (6/18) in the transarterial group (p = 0.02, 95% CI, 0.09-0.97). There was no procedure-related mortality. Moderate-severe AE occurred in 15.7% (3/19) in the DSP group and 8.7% (2/23) in the transarterial group (p = 0.44, -0.12-0.26). CONCLUSION: In this study, DSP embolization of T2EL was equally safe and more effective than transarterial embolization in achieving aneurysm sac stability and resolution of endoleak.

Performance of clear cell likelihood scores in characterizing solid renal masses at multiparametric MRI: an external validation study.

PURPOSE: The purpose of this study is to evaluate the accuracy and interobserver agreement of ccLS in diagnosing clear cell renal cell carcinoma (ccRCC). METHODS: This retrospective single-center study evaluated consecutive patients with solid renal masses who underwent mpMRI followed by percutaneous biopsy and/or surgical excision between January 2010 and December 2020. Predominantly (> 75%) cystic masses, masses with macroscopic fat and infiltrative masses were excluded. Two abdominal radiologists independently scored each renal mass according to the proposed ccLS algorithm. The diagnostic performance of ccLS categories for ccRCC was calculated using logistic regression modeling. Diagnostic accuracy for predicting ccRCC was calculated using 2 × 2 contingency tables. Interobserver agreement for ccLS was evaluated with Cohen's k statistic. RESULTS: A total of 79 patients (mean age, 63 years ± 12 [SD], 50 men) with 81 renal masses were evaluated. The mean size was 36 mm ± 28 (range 10-160). Of the renal masses included, 44% (36/81) were ccRCC. The area under the receiver operating characteristic curve was 0.87 (95% CI 0.79-0.95). Using ccLS ≥ 4 to diagnose ccRCC, the sensitivity, specificity, and positive predictive value were 93% (95% CI 79, 99), 63% (95% CI 48, 77), and 67% (95% CI 58, 75), respectively. The negative predictive value of ccLS ≤ 2 was 93% (95% CI 64, 99). The proportion of ccRCC by ccLS category 1 to 5 were 10%, 0%, 10%, 57%, and 84%, respectively. Interobserver agreement was moderate (k = 0.47). CONCLUSION: In this study, clear cell likelihood score had moderate interobserver agreement and resulted in 96% negative predictive value in excluding ccRCC.

MRI characterization of focal liver lesions in non-cirrhotic patients: assessment of added value of gadoxetic acid-enhanced hepatobiliary phase imaging.

BACKGROUND: To evaluate the added value of the hepatobiliary (HPB) phase in gadoxetic acid-enhanced magnetic resonance imaging (MRI) in characterizing newly discovered indeterminate focal liver lesions in non-cirrhotic patients. RESULTS: One-hundred and twenty-five non-cirrhotic patients (median age, 46 years; range, 20-85 years; 100 females) underwent gadoxetic acid-enhanced MRI, including the 20-min delayed HPB phase, for characterization of newly discovered focal liver lesions. Images were independently evaluated by two blinded, board-certified abdominal radiologists (R1 and R2) who characterized liver lesions without and with assessment of the HPB phase images in two separate readout sessions. Confidence in diagnosis was scored on a scale from 0 to 3. Inter-observer agreement was assessed using Cohen κ statistics. Change in diagnosis and confidence in diagnosis were evaluated by Wilcoxon signed rank test. There was no significant change in diagnosis before and after evaluation of the HPB phase for both readers (p = 1.0 for R1; p = 0.34 for R2). Confidence in diagnosis decreased from average 2.8 ± 0.45 to 2.6 ± 0.59 for R1 and increased from 2.6 ± 0.83 to 2.8 ± 0.46 for R2. Change in confidence was only statistically significant for R1 (p = 0.003) but not significant for R2 (p = 0.49). Inter-reader agreement in diagnosis was good without (k = 0.66) and with (k = 0.75) inclusion of the HPB phase images. CONCLUSIONS: The added information obtained from the HPB phase of gadoxetic acid-enhanced MRI does not change the diagnosis or increase confidence in diagnosis when evaluating new indeterminate focal liver lesions in non-cirrhotic patients.

Splenic Artery Embolization in Blunt Trauma: A Single-Center Retrospective Comparison of the Use of Gelatin Sponge Versus Coils.

OBJECTIVE: The purpose of this study was to compare the efficacy of gelatin sponge with that of coils for splenic artery embolization in the treatment of blunt splenic injury. MATERIALS AND METHODS: A single-center retrospective review was performed with the records of 63 patients (45 men, 18 women; mean age, 45.5 years; range, 16-84 years) with blunt splenic injury treated at a tertiary care trauma center by splenic artery embolization with gelatin sponge (n = 30 patients) or metallic coils (n = 33 patients) between 2005 and 2014. The two groups had comparable median American Association for the Surgery of Trauma grades of IV and comparable angiographic appearances regarding active extravasation and pseudoaneurysm formation at preembolization splenic arteriography (p = 0.32). Clinical outcomes and procedure-related outcomes were evaluated. RESULTS: The success rates were similar in the two groups: splenic artery embolization failed in 6.6% (2/30) of patients in the gelatin sponge group and 12.1% (4/33) in the coil embolization group (p = 0.45; 95% CI, -30.1% to 19.2%). Major complications occurred in six patients (20.0%) in the gelatin sponge group and in six patients (18.1%) in the coil group (p = 0.85; 95% CI, -23.0% to 26.6%). Minor complications occurred in three patients (10.0%) in the gelatin sponge group and seven patients (21.2%) in the coil group (p = 0.21; 95% CI, -35.4% to 14.0%). Procedure time was significantly shorter in the gelatin sponge group (median, 32 minutes; interquartile range, 18-48 minutes) than in the coil group (median, 53 minutes; interquartile range, 30-76 minutes) (p = 0.01). CONCLUSION: Splenic artery embolization with gelatin sponge appears to be as effective and as safe as coil embolization and can be completed in a shorter time.

Utility of MRI to Differentiate Clear Cell Renal Cell Carcinoma Adrenal Metastases From Adrenal Adenomas.

OBJECTIVE: The purpose of this study is to compare MRI features of clear cell renal cell carcinoma (RCC) adrenal metastases and adenomas. MATERIALS AND METHODS: Fifteen clear cell RCC adrenal metastases imaged with MRI were compared to 29 consecutive adenomas between 2006 and 2015. Two blinded radiologists assessed homogeneity (homogeneous vs heterogeneous), signal intensity (SI) decrease on chemical-shift MRI, and T2-weighted SI (isointense, mildly hyperintense, or markedly hyperintense) relative to muscle. A third blinded radiologist measured the chemical-shift SI index, adrenal-to-spleen SI ratio, T2-weighted SI ratio, AUC for contrast-enhanced MRI, and histogram analysis. Analyses were performed using chi-square, linear regression, ROC, and logistic regression modeling. RESULTS: Clear cell RCC metastases were larger than adenomas (mean [± SD], 5.0 ± 4.2 cm [range, 1.1-15 cm] vs 2.0 ± 0.7 cm [range, 1.2-3.7 cm]; p < 0.0001). Subjectively, 33.3% (5/15) of metastases and 68.9% (20/29) of adenomas showed an SI decrease on chemical-shift MRI (p = 0.0421; κ = 0.76). Chemical-shift SI index (mean, 9.2% ± 20.6%; range, -30.0% to 57.9%) and adrenal-to-spleen SI ratio (0.94 ± 0.23 [range, 0.44-1.33]) for metastases differed significantly from those for adenomas (47.3% ± 27.8% [range, -9.4% to 86%] and 0.52 ± 0.28 [range, 0.13-1.11], respectively) (p < 0.0001). Twenty percent (3/15) of metastases had chemical-shift SI index in the adenoma range (> 16.5%). Metastases had higher T2-weighted SI than did adenomas, both quantitatively (5.1 ± 3.0 [range, 1.5-10.6] vs 1.8 ± 0.8 [range, 0.5-3.8]; p < 0.0001) and subjectively (p < 0.0001; κ = 0.89). Metastases had higher entropy than did adenomas (6.76 ± 0.61 vs 6.1 ± 0.74; p = 0.0051) and were subjectively more heterogeneous (p < 0.0001; κ = 0.86). The contrast-enhanced MRI AUC, skewness, and kurtosis did not differ between groups (p > 0.05). The ROC AUCs were 0.91 (95% CI, 0.79-1.0) for T2-weighted SI ratio and 0.85 (95% CI, 0.68-1.0) for entropy. The logistic regression model of T2-weighted SI ratio plus entropy improved accuracy (ROC AUC, 0.97; 95% CI, 0.93-1.0]) compared with either feature alone (p = 0.0215). CONCLUSION: Increased T2-weighted SI and heterogeneity are features that can differentiate clear cell RCC adrenal metastases from adenomas using quantitative and subjective analysis.

Case 232: Amyloid ß-related Angiitis.

History A 78-year-old woman presented to a community hospital after an unwitnessed fall at her nursing home. Initial head computed tomography (CT) performed in the emergency department showed vasogenic edema in the right temporal parietal region, which prompted her transfer to our institution for additional work-up. Further history taking revealed recurrent transient motor and sensory transient ischemic attack-like symptoms over the preceding weeks. She denied having a fever or night sweats. There was no history of infection, bleeding, immunodeficiency, intravenous drug use, alcohol or tobacco abuse, malignancy, or genetic disorders. Her medical history included memory impairment and a left posterior cerebral artery territory infarction. She was not known to have any systemic inflammatory disorder. Physical examination findings at presentation were noncontributory. She was not taking any anticoagulants or immunosuppressive medication. Pertinent hematologic laboratory investigations revealed a white blood cell count of 6.7 × 10(9), a C-reactive protein level of 29 mg/L (276.2 nmol/L) (normal value, <10 mg/L [95.2 nmol/L]), and an erythrocyte sedimentation rate of 35 mm per hour (normal value, 0-10 mm per hour). Shortly after this patient was admitted to our institution, she had a generalized tonic-clonic seizure. Magnetic resonance (MR) imaging of the brain was performed the next day.

Beyond ureterolithiasis: gamut of abnormalities affecting the ureter.

Nephrolithiasis is the most common condition involving the ureters. However, various other entities can affect the ureters, albeit less frequently. Imaging plays a crucial role in diagnosis, management, and follow-up of ureteral pathology. In the past decade, computed tomography urography has replaced traditional methods of ureteral imaging due to its high spatial resolution, multiplanar imaging, and rapid acquisition time. More recently, magnetic resonance urography has also been explored in evaluating ureteral abnormalities. In this review, we briefly discuss current imaging techniques used in assessment of the ureters and present a diverse group of diseases affecting the ureters. We begin with primary and secondary ureteral malignancies, followed by uncommon infectious/inflammatory diseases that can involve the ureters including tuberculosis, xanthogranulomatous pyelonephritis, and graft-versus-host disease. We then discuss the imaging characteristics of endometriosis and retroperitoneal fibrosis as two important examples of pelvic and retroperitoneal processes that occasionally obstruct the ureters and present with clinical symptoms similar to that of renal stones. We end with a brief discussion of miscellaneous conditions that affect the ureters, including ureteral hemorrhage, ureteral intussusception, ureteral pseudodiverticulosis, Malacoplakia, and ureteritis cystica. Knowledge of these entities and their characteristic imaging manifestations along with patient's clinical presentation allows accurate diagnosis and timely patient management.

MRI evaluation of small (<4cm) solid renal masses: multivariate modeling improves diagnostic accuracy for angiomyolipoma without visible fat compared to univariate analysis.

OBJECTIVE: To assess MRI for diagnosis of angiomyolipoma without visible fat (AMLwvf). MATERIAL AND METHODS: With IRB approval, a retrospective study in consecutive patients with contrast-enhanced (CE)-MRI and <4 cm solid renal masses from 2002-2013 was performed. Ten AMLwvf were compared to 77 RCC; 33 clear cell (cc), 35 papillary (p), 9 chromophobe (ch). A blinded radiologist measured T2W signal-intensity ratio (SIR), chemical-shift (CS) SI-index and area under CE-MRI curve (CE-AUC). Regression modeling and ROC analysis was performed. RESULTS: T2W-SIR was lower in AMLwvf (0.64 ± 0.12) compared to cc-RCC (1.37 ± 0.30, p < 0.001), ch-RCC (0.94 ± 0.19, p = 0.005) but not p-RCC (0.74 ± 0.17, p = 0.2). CS-SI index was higher in AMLwvf (16.1 ± 31.5 %) compared to p-RCC (-5.2 ± 26.1 %, p = 0.02) but not ch-RCC (3.0 ± 12.5 %, p = 0.1) or cc-RCC (7.7 ± 17.9 %,p = 0.1). CE-AUC was higher in AMLwvf (515.7 ± 144.7) compared to p-RCC (154.5 ± 92.8, p < 0.001) but not ch-RCC (341.5 ± 202.7, p = 0.07) or cc-RCC (520.9 ± 276.9, p = 0.95). Univariate ROC-AUC were: T2SIR = 0.86 (CI 0.77-0.96); CE-AUC = 0.76 (CI 0.65-0.87); CS-SI index = 0.66 (CI 0.4.3-0.85). Logistic regression models improved ROC-AUC, A) T2 SIR + CE-AUC = 0.97 (CI 0.93-1.0) and T2 SIR + CS-SI index = 0.92 (CI 0.84-0.99) compared to univariate analyses (p < 0.05). The optimal sensitivity/specificity of T2SIR + CE-AUC and T2SIR + CS-SI index were 100/88.8 % and 60/97.4 %. CONCLUSION: MRI, using multi-variate modelling, is accurate for diagnosis of AMLwvf. KEY POINTS: • AMLwvf are difficult to prospectively diagnose with imaging. • MRI findings associated with AMLwvf overlap with various RCC subtypes. • T2W-SI combined with chemical-shift SI-index is specific for AMLwvf but lacks sensitivity. • T2W-SI combined with AUC CE-MRI is sensitive and specific for AMLwvf. • Models incorporating two or more findings are more accurate than univariate analysis.

Intracellular lipid in clear cell renal cell carcinoma tumor thrombus and metastases detected by chemical shift (in and opposed phase) MRI: radiologic-pathologic correlation.

BACKGROUND: Clear cell renal cell carcinoma (RRC) characteristically contain intracellular lipid which is also detectable in tumor thrombus and metastases. PURPOSE: To assess the incidence of intracellular lipid in clear cell RCC metastases and tumor thrombus using chemical shift MRI. MATERIAL AND METHODS: With REB approval, 33 consecutive patients with clear cell RCC and tumor thrombus/metastatic disease underwent magnetic resonance imaging (MRI) over a 10-year period. Diagnosis was established by histopathology for tumor thrombi (n = 25) and metastases (n = 15) or growth for metastases (n = 14). Two blinded radiologists independently assessed for a signal intensity (SI) drop at chemical shift MRI (indicative of intracellular lipid) and a third radiologist established consensus. Chemical shift SI (CS-SI) index ([SItumorIP - SItumorOP]/SITumorIP x 100) was calculated. Inter-observer agreement was assessed using intra-class correlation (ICC) and tests of association were performed using the Chi-square test and Spearman correlation. RESULTS: Using CS-MRI, intracellular lipid was detected in 36.4% of clear cell RCC, with moderate agreement, (ICC = 0.5). Intracellular lipid was detected in 20% of tumor thrombi and 20% of metastases with strong agreement (ICC = 0.73). Intracellular lipid within tumor thrombi/metastases was not associated with lipid within the primary tumor (P = 0.09). There was a correlation in CS-SI index between primary tumor and thrombi/metastases when lipid was detected in both lesions (r = 0.91, P = 0.005); however, there was no correlation when lipid was not detected in both lesions (r = -0.09, P = 0.72). CONCLUSION: The presence of intracellular lipid in tumor thrombus and metastases from clear cell RCC is uncommon and, is not necessarily associated with lipid within the primary tumor at chemical shift MRI.

False positive and false negative diagnoses of prostate cancer at multi-parametric prostate MRI in active surveillance.

MP-MRI is a critical component in active surveillance (AS) of prostate cancer (PCa) because of a high negative predictive value for clinically significant tumours. This review illustrates pitfalls of MP-MRI and how to recognise and avoid them. The anterior fibromuscular stroma and central zone are low signal on T2W-MRI/apparent diffusion coefficient (ADC), resembling PCa. Location, progressive enhancement and low signal on b ≥1000 mm²/s echo-planar images (EPI) are differentiating features. BPH can mimic PCa. Glandular BPH shows increased T2W/ADC signal, cystic change and progressive enhancement; however, stromal BPH resembles transition zone (TZ) PCa. A rounded morphology, low T2 signal capsule and posterior/superior location favour stromal BPH. Acute/chronic prostatitis mimics PCa at MP-MRI, with differentiation mainly on clinical grounds. Visual analysis of diffusion-weighted MRI must include EPI and appropriate windowing of ADC. Quantitative ADC analysis is limited by lack of standardization; the ADC ratio and ADC histogram analysis are alternatives to mean values. DCE lacks standardisation and has limited utility in the TZ, where T2W/DWI are favoured. Targeted TRUS-guided biopsies of MR-detected lesions are challenging. Lesions detected on MP-MRI may not be perfectly targeted with TRUS and this must be considered when faced with a suspicious lesion on MP-MRI and a negative targeted TRUS biopsy histopathological result. KEYPOINTS: • Multi-parametric MRI plays a critical role in prostate cancer active surveillance. • Low T2W signal intensity structures appear dark on ADC, potentially simulating cancer. • Stromal BPH mimics cancer at DWI and DCE. • Long b value trace EPI should be reviewed • Targeted biopsy of MR-detected lesions using TRUS guidance may be challenging.

Intracellular lipid in papillary renal cell carcinoma (pRCC): T2 weighted (T2W) MRI and pathologic correlation.

OBJECTIVE: To evaluate if pRCCs demonstrate intracellular lipid (i-lipid) at chemical-shift (CS) MRI, and assess T2W-MRI and pathologic characteristics. METHODOLOGY: Sixty-two patients with a pRCC diagnosis underwent MRI over 11 years (IRB-approved). Two radiologists independently assessed for presence of i-lipid on CS-MRI and homogeneity on T2W-MRI. Inter-observer agreement was assessed via an intraclass correlation and results were compared using the Chi-square test. Discordant cases were reviewed to establish consensus. T2W SI-ratios (SI.tumor/SI.kidney) and CS-SI index were compared using independent t-tests and Spearman correlation. Two pathologists re-evaluated the histopathology. RESULTS: Nine of the 62 pRCCs (14.5%) demonstrated i-lipid; agreement was moderate (ICC = 0.63). Pathology review depicted clear cells in four tumours and foamy histiocytes in five tumours. 25.8-35.4% (ICC = 0.65) of tumours were homogeneous on T2W-MRI. No pRCC with i-lipid was considered homogeneous (p = 0.01-0.04). Overall, T2W SI-ratio and CS-SI index were 0.89 (±0.29) and -3.63 % (-7.27 to 11.42). pRCC with i-lipid had significantly higher T2W SI-ratio (p = 0.003). There was a correlation between the CS-SI index and T2W SI-ratio, (r = 0.44, p < 0.001). CONCLUSIONS: Intracellular lipid is uncommonly detected in pRCCs due to clear cell changes and foamy histiocytes. These tumours are associated with heterogeneously-increased SI in T2W-MRI. KEY POINTS: • A minority of pRCCs demonstrate intracellular lipid in CS-MRI. • Quantitatively, intracellular lipid in pRCCs is minimal (<25%). • Intracellular lipid in pRCCs are from clear cell heterogeneity or foamy histiocytes. • pRCCs with intracellular lipid are heterogeneously hyperintense at T2W-MRI. • pRCCs that are homogeneously hypointense at T2W-MRI do not contain intracellular lipid.