Percutaneous Image-Guided Biopsy of the Spleen: Experience at a Single Tertiary Care Center.

PURPOSE: The purpose of this study is to assess the complication rate of percutaneous image-guided biopsy of the spleen at our institution and to evaluate for variables associated with complication rate. METHODS: This is a Research Ethics Board approved retrospective study of consecutive patients who underwent image-guided biopsy of the spleen at our institution from January 2010 to November 2019. Complications, imaging findings, and pathologic diagnosis were reviewed. Complications (major and minor) were classified per Society of Interventional Radiology Guidelines, and complication rate was calculated. Logistic regression was applied to determine factors associated with complications. Diagnostic yield was calculated. RESULTS: In all, 55 patients (28 female) underwent splenic biopsy using ultrasound guidance. The most common indication was possible lymphoma in 41 (71.7%) patients followed by query metastasis 18 (31.5%) patients. Core biopsies (18 g/20 g) were done in 53 (92%) cases, and fine-needle aspiration (22 g) was performed in 4 (8%). The median number of samples collected was 4 (range: 2-9). The results were diagnostic in 54 cases (94.7%, 95% confidence interval [CI]: 88.7-100.0). There were 12 (21%, 95% CI: 10.1-31.9) patients with minor complications and 2 (3.5%, 95% CI: 0.0-8.4) with major complications (2 splenic bleeds requiring embolization, no splenectomy, or deaths). No variables (needle size, lesion size, and number of passes) were associated with complication rate. CONCLUSION: Percutaneous image-guided biopsy of the spleen at a single tertiary care institution demonstrates major complication rate comparable to that in the literature with no variables associated with complication rate; there were no cases of splenectomy or death.

Gallbladder Cancer: Imaging Appearance and Pitfalls in Diagnosis [Formula: see text].

Gallbladder cancer is an uncommon malignancy with an overall poor prognosis. The clinical and imaging presentation of gallbladder cancer often overlaps with benign disease, making diagnosis difficult. Gallbladder cancer is most easily diagnosed on imaging when it presents as a mass replacing the gallbladder. At this stage, the prognosis is usually poor. Recognizing the features of gallbladder cancer early in the disease can enable complete resection and improve prognosis. Recognition of the patterns of wall enhancement on computed tomography can help differentiate gallbladder cancer from benign disease. Gallbladder wall thickening without pericholecystic fluid presenting in an older patient with raised alkaline phosphatase should raise concern regarding gallbladder cancer. Gallbladder polyps in high-risk individuals need close surveillance or surgery as per guidelines. Small gallbladder cancers in the neck can present as biliary dilatation or cholecystitis, and careful examination of this area is needed to assess for lesion. The imaging appearance of gallbladder cancer is reviewed and supported by local institutional data. Features that differentiate it from its common mimics enabling earlier diagnosis are described.

Regional Standardization of Prostate Multiparametric MRI Performance and Reporting: Is There a Role for a Director of Prostate Imaging?

OBJECTIVE. The purpose of this study was to assess prostate multiparametric MRI (mpMRI) before and after intervention by a director of prostate imaging. MATERIALS AND METHODS. Images from prostate mpMRI examinations at four peripheral institutions (five 1.5-T systems) were studied. DICOM headers were analyzed for T2-weighted, DWI, and dynamic contrast-enhanced technical specifications. Reports were retrieved, and a blinded radiologist compared them with those from the regional academic referral center (3-T system) and Prostate Imaging and Data Reporting System version 2 (PI-RADSv2) technical specifications. Data were reevaluated after intervention by a director of prostate imaging. Comparisons were performed by chi-square analysis. RESULTS. Except for having insufficient DWI spatial resolution, the referral center fully complied with PI-RADSv2. For peripheral systems, compliance with PI-RADSv2 technical specifications improved from baseline to after intervention. For T2-weighted imaging, compliance with spatial resolution increased from 40% (two of five MRI systems) to 100% (all five systems) (p = 0.038). For DWI, spatial resolution compliance increased from 20% to 100%. For modified DWI, spatial resolution compliance to improve image quality at 1.5 T (matrix, 100 × 100; FOV, 28 × 28 cm; slice thickness, 4 mm) increased from 60% (b value ≥ 1400 s/mm2) to 100% (p = 0.114). For dynamic contrast-enhanced imaging, spatial resolution compliance increased from 60% to 100% (p = 0.114), temporal resolution compliance increased from 20% (≤ 10 seconds) to 100% (p = 0.10), and acquisition time compliance increased from 60% (≥ 2 minutes) to 100% (p = 0.114). Only one of the four peripheral centers provided PI-RADSv2 scores, but all of them did after the intervention (p = 0.028). CONCLUSION. A director of prostate imaging may drive standardization of prostate MRI performance and reporting within specified geographic regions.

Diagnostic Yield and Complication Rate in Percutaneous Needle Biopsy of Renal Hilar Masses With Comparison With Renal Cortical Mass Biopsies in a Cohort of 195 Patients.

OBJECTIVE: The objective of this study was to compare diagnostic yield and complication rate in needle biopsy (NB) of renal hilar and cortical masses. MATERIALS AND METHODS: With institutional review board approval, we retrospectively studied 195 patients (120 men, 75 women; mean age ± SD, 67 ± 13 years old) who underwent ultrasound-guided renal mass NB between January 2013 and December 2017. Operator years of experience, biopsy technique (coaxial or successive), needle gauge (22-gauge fine-needle aspiration, 18-gauge core-needle, or both), number of passes, postprocedural complication, and histopathologic diagnoses were recorded. A radiologist who was blinded to histopathologic diagnoses recorded mass location (upper pole, interpolar region, lower pole) and percentage of hilar involvement. Comparisons were performed using independent t and chi-square tests. RESULTS: Of the masses biopsied, 5.6% (11/195) were 100% hilar (mean hilar involvement, 20.8% ± 29.8%; range, 0-100%). Mean lesion size was 44 ± 27 mm (range, 12-157 mm). NB diagnosis was established in 84.6% (165/195) of masses, and 15.4% (30/195) of biopsies were inconclusive, with no association with size (p = 0.55) or percentage of hilar involvement (p = 0.756). In the purely hilar masses, diagnosis was established in 72.7% (8/11) compared with 85.3% (157/184) with any cortical involvement (p = 0.265). There was no association between diagnosis and operator years of experience, biopsy technique, needle gauge, or number of passes (p > 0.05). Bleeding occurred after biopsy in 7.7% (15/195) of cases, was associated with percentage of hilar involvement (39.3% ± 44.9% vs 19.3% ± 27.8%; p = 0.012), and was more common in purely hilar masses (36.4% [4/11] vs 5.6% [11/195]; p < 0.001). Complications were not associated with any other feature (p > 0.05). CONCLUSION: Percutaneous biopsy of renal hilar masses is technically feasible with diagnostic yield similar to that of cortical masses but with postprocedural bleeding more often than what is seen with cortical masses.

Evaluation of MRI for diagnosis of extraprostatic extension in prostate cancer.

PURPOSE: To assess the ability of magnetic resonance imaging (MRI) to diagnose extraprostatic extension (EPE) in prostate cancer. MATERIALS AND METHODS: With Institutional Review Board (IRB) approval, 149 men with 170 ≥0.5 mL tumors underwent preoperative 3T MRI followed by radical prostatectomy (RP) between 2012-2015. Two blinded radiologists (R1/R2) assessed tumors using Prostate Imaging Reporting and Data System (PI-RADS) v2, subjectively evaluated for the presence of EPE, measured tumor size, and length of capsular contact (LCC). A third blinded radiologist, using MRI-RP-maps, measured whole-lesion: apparent diffusion coefficient (ADC) mean/centile and histogram features. Comparisons were performed using chi-square, logistic regression, and receiver operator characteristic (ROC) analysis. RESULTS: The subjective EPE assessment showed high specificity (SPEC = 75.4/91.3% [R1/R2]), low sensitivity (SENS = 43.3/43.6% [R1/R2]), and area-under (AU) ROC curve = 0.67 (confidence interval [CI] 0.61-0.73) R1 and 0.61 (CI 0.53-0.70) R2; (k = 0.33). PI-RADS v2 scores were strongly associated with EPE (P < 0.001 / P = 0.008; R1/R2) with AU-ROC curve = 0.72 (0.64-0.79) R1 and 0.61 (0.53-0.70) R2; (k = 0.44). Tumors with EPE were larger (18.8 ± 7.8 [median 17, range 6-51] vs. 18.8 ± 4.9 [12, 6-28] mm) and had greater LCC (21.1 ± 14.9 [16, 1-85] vs. 13.6 ± 6.1 [11.5, 4-30] mm); P < 0.001 and 0.002, respectively. AU-ROC for size was 0.73 (0.64-0.80) and LCC was 0.69 (0.60-0.76), respectively. Optimal SENS/SPEC for diagnosis of EPE were: size ≥15 mm = 67.7/66.7% and LCC ≥11 mm = 84.9/44.8%. 10th -centile ADC and ADC entropy were both associated with EPE (P = 0.02 and < 0.001), with AU-ROC = 0.56 (0.47-0.65) and 0.76 (0.69-0.83), respectively. Optimal SENS/SPEC for diagnosis of EPE with entropy ≥6.99 was 63.3/75.0%. 25th -centile ADC trended towards being significantly lower with EPE (P = 0.06) with no difference in other ADC metrics (P = 0.25-0.88). Size, LCC, and ADC entropy improved sensitivity but reduced specificity compared with subjective analysis with no difference in overall accuracy (P = 0.38). CONCLUSION: Measurements of tumor size, capsular contact, and ADC entropy improve sensitivity but reduce specificity for diagnosis of EPE compared to subjective assessment. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:176-185.

Diagnostic Accuracy of Qualitative and Quantitative Computed Tomography Analysis for Diagnosis of Pathological Grade and Stage in Upper Tract Urothelial Cell Carcinoma.

OBJECTIVE: The aim of this study was to compare grade and stage of upper tract urothelial cell carcinoma (UCC) using computed tomography. MATERIALS AND METHODS: With institutional review board approval, 48 patients with 49 UCC (44 high grade and 5 low grade, 26 ≤ T1 and 23 ≥ T2) underwent nephroureterectomy and preoperative computed tomography between 2013 and 2015. Two blinded radiologists assessed for tumor appearance (filling defect/mass or wall thickening/stricture), margin (smooth or spiculated/irregular), texture (homogeneous, heterogeneous), hydronephrosis, and calcification. A third blinded radiologist established consensus. A fourth blinded radiologist measured size and first-order histogram texture features. Comparisons were performed using χ test, multivariable logistic regression, and receiver operator characteristic analysis. RESULTS: There was no difference in size of tumors compared by grade or stage (P = 0.80 and 0.13, respectively).Among subjective variables, only tumor texture was significantly different between low- and high-grade UCC (P = 0.03; κ = 0.45). Tumors characterized as spiculated/irregular margin (P = 0.003; 0.30) and heterogeneous (P < 0.001; κ = 0.45) were associated with T2 disease or higher.Entropy was greater in higher grade (6.23 ± 0.46 vs 5.72 ± 0.28) and T2 disease or higher (6.40 ± 0.33 vs 5.95 ± 0.48), (P = 0.03 and 0.02, respectively) with no differences in Kurtosis or Skewness (P > 0.05). Area under the receiver operator characteristic curve for entropy to diagnose high-grade and T2 tumors or higher was 0.83 (confidence interval, 0.64-1.0) and 0.79 (confidence interval 0.59-0.98), respectively. CONCLUSIONS: Heterogeneity, assessed qualitatively and quantitatively, is accurate for diagnosis of higher grade and stage of disease in upper tract UCC. Spiculated/irregular margins are also associated with T2 disease or higher.

Gadolinium-Based Contrast Agents in Kidney Disease: Comprehensive Review and Clinical Practice Guideline Issued by the Canadian Association of Radiologists.

Use of gadolinium-based contrast agents (GBCAs) in renal impairment is controversial, with physician and patient apprehension in acute kidney injury (AKI), chronic kidney disease (CKD), and dialysis because of concerns regarding nephrogenic systemic fibrosis (NSF). The position that GBCAs are absolutely contraindicated in AKI, CKD stage 4 or 5 (estimated glomerular filtration rate [eGFR] <30 mL/min/1.73 m2) and dialysis-dependent patients is outdated, and may limit access to clinically necessary contrast-enhanced MRI examinations. Following a comprehensive review of the literature and reported NSF cases to date, a committee of radiologists and nephrologists developed clinical practice guidelines to assist physicians in making decisions regarding GBCA administrations. In patients with mild-to-moderate CKD (eGFR ≥30 and <60 mL/min/1.73 m2), administration of standard doses of GBCA is safe and no additional precautions are necessary. In patients with AKI, with severe CKD (eGFR <30 mL/min/1.73 m2), or on dialysis, administration of GBCAs should be considered individually and alternative imaging modalities utilized whenever possible. If GBCAs are necessary, newer GBCAs may be administered with patient consent obtained by a physician (or their delegate), citing an exceedingly low risk (much less than 1%) of developing NSF. Standard GBCA dosing should be used; half or quarter dosing is not recommended and repeat injections should be avoided. Dialysis-dependent patients should receive dialysis; however, initiating dialysis or switching from peritoneal to hemodialysis to reduce the risk of NSF is unproven. Use of a macrocyclic ionic instead of macrocyclic nonionic GBCA or macrocyclic instead of newer linear GBCA to further prevent NSF is unproven. Gadopentetate dimeglumine, gadodiamide, and gadoversetamide remain absolutely contraindicated in patients with AKI, with stage 4 or 5 CKD, or on dialysis. The panel agreed that screening for renal disease is important but less critical when using macrocyclic and newer linear GBCAs. Monitoring for and reporting of potential cases of NSF in patients with AKI or CKD who have received GBCAs is recommended.

Prognostic value of Prostate Imaging and Data Reporting System (PI-RADS) v. 2 assessment categories 4 and 5 compared to histopathological outcomes after radical prostatectomy.

PURPOSE: To assess Prostate Imaging and Data Reporting System (PI-RADS) v. 2 score 4/5 lesions compared to Gleason score (GS) and stage after radical prostatectomy (RP) and to validate the proposed 15-mm size threshold that differentiates category 4 versus 5 lesions. MATERIALS AND METHODS: With Institutional Review Board (IRB) approval, 140 men underwent 3T magnetic resonance imaging (MRI) and RP between 2012-2015. Two blinded radiologists: 1) assigned PI-RADS v. 2 scores, 2) measured tumor size on axial T2 -weighted-MRI, and 3) assessed for extraprostatic extension (EPE). Interobserver agreement was calculated and consensus diagnoses achieved through reference standard (MRI-RP maps). PI-RADS v. 2 scores and tumor size were compared to GS and stage using chi-square, analysis of variance (ANOVA), and receiver operating characteristic (ROC) curve analysis. RESULTS: In all, 80.7% (113/140) of tumors were category 4 (n = 45) or 5 (n = 68) lesions (κ = 0.45). Overall tumor size was 18.2 ± 7.7 mm and category 5 lesions were larger (22.6 ± 6.8 versus 11.5 ± 1.9 mm, P < 0.001). High-risk (GS ≥8) tumors were larger than low- and intermediate-risk tumors (P = 0.016) and were more frequently, but not significantly so, category 5 lesions (78.9% [15/19] vs. 22.1% [4/10], P = 0.18). 67.3% (76/113) of patients had EPE. Category 5 lesions were strongly associated with EPE (P < 0.0001). Area under the ROC curve for diagnosis of EPE by size was 0.74 (confidence interval 0.64-0.83), with size ≥15 mm yielding a sensitivity/specificity of 72.4/64.9%. Size improved sensitivity for diagnosis of EPE compared to subjective assessment (sensitivity/specificity ranging from 46.1-48.7%/70.3-86.5%, κ = 0.29) (P = 0.028). CONCLUSION: PI-RADS v. 2 category 5 lesions are associated with higher Gleason scores and EPE. A 15-mm size threshold is reasonably accurate for diagnosis of EPE with increased sensitivity compared to subjective assessment. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:257-266.

Is Ultrasound Useful for Further Evaluation of Homogeneously Hyperattenuating Renal Lesions Detected on CT?

OBJECTIVE: The purpose of this study was to evaluate the ability of ultrasound (US) to characterize hyperattenuating cysts detected as indeterminate hyperattenuating renal lesions on unenhanced and single phase enhanced CT. MATERIALS AND METHODS: A total of 107 consecutive homogeneously hyperattenuating renal lesions underwent gray-scale and Doppler US at our institution between 2010 and 2013. Two radiologists who were unaware of the final diagnosis retrospectively evaluated US images for visibility and diagnosis (simple cyst, intermediate complexity cyst, cystic or solid mass showing internal flow on Doppler US, or indeterminate). A third radiologist assessed lesion size, location, and distance to skin on CT and US. US visibility was compared using chi-square and independent t tests. Consensus US interpretation was compared with reference standard diagnoses, and accuracy for diagnosis of hyperattenuating cysts was tabulated. RESULTS: Mean lesion size ± SD was 20 ± 16 mm (range, 6-96 mm) and mean distance to skin on CT was 62 ± 25 mm (range, 18-125 mm). In all, 89.7% (96/107) of the lesions were visible on US, including all lesions that were 15 mm or larger. Nonvisible lesions were smaller than visible ones (10.0 ± 3.6 mm vs 20.7 ± 16.3 mm, p = 0.03) regardless of location (p > 0.05). CT overestimated lesion distance to skin compared with US (46.6 ± 18.6 mm, p < 0.001). Final diagnoses for US visible lesions (n = 96) were hyperattenuating cyst (n = 66), Bosniak IIF cyst (n = 13), and cystic or solid neoplasm (n = 15); two patients were lost to follow-up. Of the 66 hyperattenuating cysts, 54 (81.8%) appeared as simple cysts on US with sensitivity and specificity for diagnosis of hyperattenuating cyst of 81.8% (95% CI, 75.6-84.3%) and 92.9% (95% CI, 78.1-98.7%), respectively. The other 12 (18.2%) hyperattenuating cysts appeared complex. Two of the 13 Bosniak IIF lesions were incorrectly classified as simple cysts with US. Including the 11 (10%) nonvisible lesions reduced sensitivity and specificity for diagnosis of hyperattenuating cyst to 73.0% (95% CI, 66.9-75.9%) and 89.7% (95% CI, 74.2-97.2%), respectively. CONCLUSION: US can further characterize hyperattenuating cysts presenting as indeterminate hyperattenuating renal lesions on CT in the majority of cases.

Evaluation of apparent diffusion coefficient and MR volumetry as independent associative factors for extra-prostatic extension (EPE) in prostatic carcinoma.

BACKGROUND: To assess mean apparent diffusion coefficient (ADC) and MR-derived tumor volume (Vt) as associative factors for extra-prostatic extension (EPE) in prostate cancer (PCa). METHODS: With institutional review board approval, 73 consecutive patients diagnosed with PCa at trans-rectal ultrasound biopsy underwent preoperative multi-parametric (T2W+DWI+DCE) 3 Tesla MRI before radical prostatectomy between 2012 and 2014; 52% (38/73) patients had EPE. Clinical parameters including: age, prostate serum antigen (PSA), digital rectal examination (DRE) and percentage positive cores (PPC) were recorded. Two blinded radiologists subjectively evaluated for EPE using PI-RADS with T2W-MRI. A third blinded radiologist recorded: mean ADC (mm(2) /s) of tumor and tumor volume on ADC and T2W (derived from planar volumetry). VtMAX (the largest volume on ADC or T2W) was documented. Multivariate and receiver operator characteristic analyses were performed. RESULTS: There were no significant differences in age, DRE, or Gleason score between groups (P = 0.52, 0.06, 0.61, 0.36). PSA approached significance being higher with EPE (12.9 ± 12.6 versus 8.2 ± 7.4; P = 0.06). PPC was higher with EPE (60.9 ± 21.9% versus 38.3 ± 21.6%; P < 0.01) with an area under the curve (AUC) of 0.78 and sensitivity/specificity = 75.7/75% when PPC ≥ 45%. AUC for T2W-MRI was 0.46-0.51 with sensitivity/specificity = 40.0-42.9/48.6-57.1% (R1, R2). Inter-observer agreement was fair, k = 0.39. There was no difference in mean ADC between groups (0.89 ± 0.25 versus 0.88 ± 0.19 [EPE] mm(2) /s), P = 0.70. T2W-Vt, ADC-Vt, and VtMAX were larger with EPE (5.1 ± 7.4, 5.8 ± 6.5, 6.3 ± 7.4 cm(3) versus 1.6 ± 1.8, 1.8 ± 1.3, 2.1 ± 1.8), P < 0.01. VtMAX AUC was 0.77 with sensitivity/specificity = 78.4/73.5% when VtMAX ≥ 2.1 cm(3) which outperformed all other parameters (P > 0.05) except PPC (P = 0.6) for the diagnosis EPE. CONCLUSION: MR volumetry and percentage of positive core biopsies are associated with EPE; whereas, in this study, other clinical and MR parameters including mean ADC and subjective T2W-MR analysis were not useful for assessment of EPE.

Comparison of Quantitative MRI and CT Washout Analysis for Differentiation of Adrenal Pheochromocytoma From Adrenal Adenoma.

OBJECTIVE: The purpose of this study was to use quantitative analysis to assess MRI and washout CT in the diagnosis of pheochromocytoma versus adenoma. MATERIALS AND METHODS: Thirty-four pheochromocytomas (washout CT, 5; MRI, 24; both MRI and CT, 5) resected between 2003 and 2014 were compared with 39 consecutive adenomas (washout CT, 9; MRI, 29; both MRI and CT, 1). A blinded radiologist measured unenhanced attenuation, 70-second peak CT enhancement, 15-minute relative and absolute percentage CT washout, chemical-shift signal intensity index, adrenal-to-spleen signal intensity ratio, T2-weighted signal intensity ratio, and AUC of the contrast-enhanced MRI curve. Comparisons between groups were performed with multivariate and ROC analyses. RESULTS: There was no difference in age or sex between the groups (p > 0.05). For CT, pheochromocytomas were larger (4.2 ± 2.5 [SD] vs 2.3 ± 0.9 mm; p = 0.02) and had higher unenhanced attenuation (35.7 ± 6.8 HU [range, 24-48 HU] vs 14.0 ± 20.9 HU [range, -19 to 52 HU]; p = 0.002), greater 70-second peak CT enhancement (92.8 ± 31.1 HU [range, 41.0-143.1 HU] vs 82.6 ± 29.9 HU [range, 50.0-139.0 HU ]; p = 0.01), lower relative washout CT (21.7 ± 24.7 [range, -29.3 to 53.7] vs 65.3 ± 22.3 [range, 32.9-115.3]; p = 0.002), and lower absolute washout CT (31.9 ± 42.8 [range, -70.6 to 70.2] vs 76.9 ± 10.3 [range, 60.3-89.6]; p = 0.001). Thirty percent (3/10) of pheochromocytomas had absolute CT washout in the adenoma range (> 60%). For MRI, pheochromocytomas were larger (5.0 ± 4.2 vs 2.0 ± 0.7 mm; p = 0.003) and had a lower chemical-shift signal intensity index and higher adrenal-to-spleen signal intensity ratio (-3.5% ± 14.3% [range, -56.3% to 12.2%] and 1.1% ± 0.1% [range, 0.9-1.3%] vs 47.3% ± 27.8% [range, -9.4% to 86.0%] and 0.51% ± 0.27% [range, 0.13-1.1%]) (p < 0.001) and higher T2-weighted signal intensity ratio (4.4 ± 2.4 vs 1.8 ± 0.8; p < 0.001). There was no statistically significant difference in contrast-enhanced MRI AUC (288.9 ± 265.3 vs 276.2 ± 129.9 seconds; p = 0.96). The ROC AUC for T2-weighted signal intensity ratio was 0.91 with values greater than 3.8 diagnostic of pheochromocytoma. CONCLUSION: In this study, the presence of intracellular lipid on unenhanced CT or chemical-shift MR images was diagnostic of adrenal adenoma. Elevated T2-weighted signal intensity ratio was specific for pheochromocytoma but lacked sensitivity. There was overlap in all other MRI and CT washout parameters.

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.

Multi-echo gradient recalled echo imaging of the pelvis for improved depiction of brachytherapy seeds and fiducial markers facilitating radiotherapy planning and treatment of prostatic carcinoma.

PURPOSE: MR localization of implanted devices for radiotherapy (RT) in prostatic carcinoma is critical for treatment planning. This clinical note studies the application of a multi-echo gradient recalled echo (GRE) pulse sequence with sum of squares echo combination (ME GRE) to enhance detection of seeds and fiducials. MATERIALS AND METHODS: Fifteen patients who underwent MRI using fast spin echo (FSE), single-echo and ME GRE over a 9-month period were retrospectively evaluated by two readers who assessed overall image quality, depiction of seeds/fiducials and image sharpness using a 5-point scale (1 = poor, 2 = suboptimal, 3 = adequate, 4 = above average, 5 = excellent). Image scores were compared using the Wilcoxon sign rank test. RESULTS: In all 15 patients, both readers rated the depiction of seeds/fiducials with ME GRE as excellent. In all 15 patients, overall image quality and image sharpness with ME GRE was rated as excellent by reader 1. In 12/15 patients, overall image quality and image sharpness with ME GRE was rated as excellent and in the other patients above average by reader 2. There was a difference in depiction of seeds/fiducials comparing GRE to FSE (P < 0.001) and ME to single echo GRE (P < 0.001). Overall image quality and sharpness was higher with ME compared with single echo GRE (P < 0.001) and similar to FSE (P = 0.26 and P = 0.16). CONCLUSION: Multi-echo GRE provides better detection of implanted seeds and fiducial markers when compared with both FSE and single-echo GRE potentially improving RT treatment planning for prostate carcinoma.

Does a cleansing enema improve image quality of 3T surface coil multiparametric prostate MRI?

PURPOSE: To assesses the utility of a preparatory enema in the interpretation of prostate multiparametric (MP) magnetic resonance imaging (MRI). MATERIALS AND METHODS: Under a waiver from the Institutional Review Board (IRB), 32 patients without bowel preparation and 28 patients who underwent a self-administered enema were imaged consecutively with 3T MP-MRI over 6 months. Two blinded radiologists independently assessed image quality on T2 -weighted (T2 W), trace b 1000 mm(2) /sec echo-planar (EPI) and apparent-diffusion coefficient (ADC) and assessed for motion/blur on T2 W and distortion/blur on EPI and ADC. Radiologists also quantified rectal stool and gas. A third blinded radiologist generated contrast curves from dynamic contrast-enhanced (DCE) data at six locations and measured the number of corrupted data points, defined as >10% aberrant signal intensity change. Subjective scores were compared using Wilcoxon sign rank test. Rectal contents were correlated to artifact using Spearman correlation. Contrast curves were evaluated with independent t-tests. RESULTS: There was no difference in image quality on T2 W (P = 0.66-0.74), EPI (P = 0.13-0.36) or ADC (P = 0.49-0.59). There was less rectal stool in the enema group (P = 0.004) and amount of stool correlated with motion artifact on T2 W (r = 0.23, P = 0.02); however, there was no difference in motion artifact between groups (P = 0.47-0.94). Only a minority of patients in the non-enema group had moderate or large amounts of stool (16%) and none of these patients had severe or extensive artifact on T2 . There was less rectal gas in the enema group (P = 0.002); however, amount of gas did not correlate with distortion artifact on EPI or ADC (P = 0.17-0.41) and there was no difference in blur (P = 0.41-0.91) or distortion (P = 0.31-0.99) on EPI or ADC between groups. There was no difference in corrupted data points on DCE (P = 0.46). CONCLUSION: In this study the use of a preparatory enema did not improve image quality or reduce artifact in prostate MP-MRI.

Solid Renal Cell Carcinoma Measuring Water Attenuation (-10 to 20 HU) on Unenhanced CT.

OBJECTIVE: The objectives of this study were to evaluate the incidence of solid renal cell carcinoma (RCC) with attenuation similar to that of water (-10 to 20 HU) on unenhanced CT and to examine imaging features that can allow RCC to be differentiated from simple cysts. MATERIALS AND METHODS: We performed an enriched quantitative and qualitative retrospective analysis of consecutive patients who underwent unenhanced CT before resection of solid (noncystic and nonnecrotic) renal masses measuring < 5 cm from 2008 to 2013. In all, 93 patients with 96 tumors (55 clear cell, 27 papillary, and 14 chromophobe) were evaluated with unenhanced CT. Attenuation was measured at three standardized levels and compared using the Kruskal-Wallis test. Two radiologists independently assessed calcification, margin (smooth or irregular), and heterogeneity (homogeneous or heterogeneous). Results were compared using the chi-square test with Bonferroni correction. RESULTS: Mean ± SD attenuation values were 31.8 ± 9.6 HU (range, 11-63 HU) overall, 29.9 ± 8.8 HU (range, 11.0-49.0 HU) for clear cell tumors, 34.6 ± 10.3 HU (range, 20.3-63.0 HU) for papillary tumors, and 35.5 ± 9.2 HU (range, 20.7-47 HU) for chromophobe tumors (p = 0.06). Eight clear cell RCCs had attenuation similar to that of water (15.7 ± 2.4 HU; range, 11-18.7 HU). There was no significant difference in calcification or margin among different types of tumors (p = 0.91 and p = 0.55, respectively). Chromophobe tumors were more likely to be homogeneous (p < 0.001). Interobserver agreement was moderate to very good (κ = 0.91 for calcification, κ = 0.55 for margin, and κ = 0.44 for heterogeneity). All eight clear cell RCCs with attenuation similar to that of water were considered heterogeneous by both readers. Irregular margins were identified in three of these eight tumors by reader 1 and four of eight tumors by reader 2. CONCLUSION: A minority of solid RCCs have attenuation similar to that of water on unenhanced CT. In this study, all such tumors were of the clear cell subtype and qualitatively heterogeneous, suggesting they can be distinguished from simple cysts on unenhanced CT.

Diagnosis of Sarcomatoid Renal Cell Carcinoma With CT: Evaluation by Qualitative Imaging Features and Texture Analysis.

OBJECTIVE: The objective of our study was to determine whether CT findings, including texture analysis, can differentiate sarcomatoid renal cell carcinoma (RCC) from clear cell RCC. MATERIALS AND METHODS: A retrospective case-control study was performed of consecutive patients with a histologic diagnosis of sarcomatoid RCC (n = 20) and clear cell RCC (n = 25) who underwent preoperative CT over a 3-year period. The CT images were independently reviewed by two blinded abdominal radiologists; they evaluated the following: tumor heterogeneity, tumor margin, calcification, intratumoral neovascularity, peritumoral neovascularity, renal sinus invasion, renal vein invasion, and adjacent organ invasion. Interobserver agreement was assessed using the Cohen kappa coefficient, and results were compared between groups using an independent Student t test and the chi-square test with a Bonferroni correction. For texture analysis, gray-level co-occurrence and run-length matrix features were extracted and compared using Mann-Whitney U tests. ROC curves for each tumor were constructed, and AUCs were calculated. RESULTS: Overall, sarcomatoid RCCs were larger than clear cell RCCs, measuring 77 ± 27 mm (mean ± SD) compared with 50 ± 29 mm (p = 0.003), respectively; however, there was no difference in tumor size between the tumors that were compared using texture analysis or subjective analysis (p = 0.06 and 0.03, respectively). From the subjective analysis, only peritumoral neovascularity (readers 1 and 2: 70% and 70% sarcomatoid RCCs vs 0% and 41.6% clear cell RCCs, respectively; p = 0.001) and the size of the peritumoral vessels (p < 0.001) differed between sarcomatoid RCCs and clear cell RCCs, and interobserver agreement was fair (κ = 0.38). Other subjective imaging features did not differ between the tumors (p > 0.005). There was greater run-length nonuniformity and greater gray-level nonuniformity in sarcomatoid RCCs than in clear cell RCCs (p = 0.03 and p = 0.04, respectively). The combined textural features identified sarcomatoid RCC with an AUC of 0.81 ± 0.08 (standard error) (p < 0.0001). CONCLUSION: Large tumor size, the presence of peritumoral neovascularity, and larger peritumoral vessels are features that are more commonly associated with sarcomatoid RCCs than with clear cell RCCs. Sarcomatoid RCCs are also more heterogeneous by texture analysis than clear cell RCCs.

Prostatic ductal adenocarcinoma: an aggressive tumour variant unrecognized on T2 weighted magnetic resonance imaging (MRI).

INTRODUCTION: Prostatic ductal adenocarcinoma (DCa) is an aggressive variant. The purpose of this study was to determine if T2 signal intensity (SI) differs from conventional adenocarcinoma (CCa). MATERIALS AND METHODS: A retrospective study of patients who underwent preoperative MRI and prostatectomy between 2009 and 2012 was performed. T2 SI ratios (SIR) for tumour (T) to obturator internus muscle (M) and normal peripheral zone (PZ) were compared. Two radiologists evaluated the central gland/PZ to detect tumours and compared diagnostic accuracy. RESULTS: T2 SIR for DCa were 3.60 (T/M), 0.66 (T/PZ); 2.68 (T/M), 0.47 (T/PZ) for Gleason 9; 2.50 (T/M), 0.47 (T/PZ) for Gleason 7/8 and 3.95 (T/M), 0.73 (T/PZ) for Gleason 6 tumours. There was a difference in T2 T/M and T/PZ SIR between DCa and Gleason 9 (p = 0.003, p = 0.004) and Gleason 7/8 (p = 0.006, p = 0.002), but no difference in SIR between DCa and Gleason 6 tumours. The sensitivity for tumour detection was 0-27 % for DCa, 64-82 % for Gleason 9, 44-88 % for Gleason 7-8 and 0-20 % for Gleason 6. There was a difference in the sensitivity of detecting Gleason 9 and 7/8 tumours when compared to DCa (p = 0.004, p = 0.001). CONCLUSIONS: DCa resembles Gleason score 6 tumour at T2-weighted MRI, which underestimates tumour grade and renders the tumour occult. KEY POINTS: Prostatic ductal adenocarcinoma is aggressive, resembling endometrial carcinoma at histopathology. Prostatic ductal adenocarcinoma resembles Gleason score 6 tumour at T2-weighted MRI. MRI grading may underestimate ductal adenocarcinoma based on increased T2 signal.

Patterns of recurrence following selective intraoperative radiofrequency ablation as an adjunct to hepatic resection for colorectal liver metastases.

BACKGROUND AND OBJECTIVES: The purpose of this study was to analyze the patterns of recurrence following intraoperative radiofrequency ablation (RFA) combined with hepatic resection for patients with colorectal liver metastases (CLM). METHODS: Patients undergoing liver resection (with or without RFA) for CLM were examined. Rates and patterns of disease recurrence, as well as overall survival were assessed using Kaplan-Meier and Cox analyses. RESULTS: A total of 174 patients underwent liver resection for CLM (150 without and 24 with intraoperative RFA). RFA was used to treat 41 tumors (median 1.6 cm). The 3-year overall survival was 65.5% and 61.4% (adjusted HR 1.02, 95% CI 0.55-1.88). Median recurrence-free survival was 7.4 versus 12.7 months with RFA versus non-RFA, respectively (adjusted HR 1.51, 95% CI 0.94-4.42). On multivariate analysis, neither survival nor recurrence-free survival was significantly associated with RFA. In total, there were two RFA ablation zone local failures. An ablation site recurrence was the sole site in one patient (4.2%). CONCLUSION: RFA was used as an adjunct to resection in patients with greater disease burden. Despite this, RFA was not significantly associated with a higher risk of local failure and was not associated with worse survival, when compared with liver resection alone.

Triphasic CT in the diagnosis of acute mesenteric ischaemia.

OBJECTIVE: To evaluate the yield of each phase in a triphasic CT protocol used to diagnose acute mesenteric ischaemia (AMI). METHODS: Retrospective analysis of patients who underwent CT to exclude AMI was conducted. From 218 patients, 80 were randomly selected for analysis: 39 with proven AMI; 41 controls. Three readers evaluated the studies; two readers were provided with only portions of the examination to determine the yield of unenhanced CT (NECT) and CT angiography (CTA). The diagnostic accuracy of CT findings was calculated and compared between readers. RESULTS: The sensitivity and specificity of submucosal haemorrhage were 10 % and 98 %. Interobserver variability was poor (κ = 0.17). All true-positive cases had other CT findings of AMI (n = 4). There was no difference in the assessment of bowel enhancement between readers (P < 0.05). There was no difference between readers (P < 0.05) and interobserver variability was moderate to good when diagnosing arterial abnormalities without CTA. Sample size was small and errors occurred when using only the portal venous phase for this purpose. CONCLUSION: NECT is not required for diagnosis of AMI. Splanchnic arterial abnormalities can be diagnosed without CTA although errors occur when using only the portal venous phase for this purpose. KEY POINTS: • Triphasic CT is the current gold standard for diagnosing acute mesenteric ischaemia. • Multiphase CT multiplies the radiation dose when compared to single phase CT. • Each phase in a multiphase CT examination should be independently validated. • Unenhanced CT is not required for diagnosis of acute mesenteric ischaemia. • CT angiography should be performed for diagnosis of acute mesenteric ischaemia.

Accuracy of sonographically guided biopsy using a freehand versus needle-guided technique: computed tomographic correlation study.

Sonographically guided biopsy is performed by one of two techniques: the freehand and needle-guided techniques. To our knowledge, the relationship between the location of the local anesthetic tract and the biopsy needle tract as well as direct comparison of the two biopsy techniques has not been previously validated. The aim of this study was to validate the different parameters related to the two biopsy techniques using computed tomography as the reference standard for assessing final tract positions. There were statistically significant differences between the freehand and guided techniques in the following parameters: number of passes required for contrast agent injection (P = .003), number of passes required to insert the needle (P = .005), time required to inject the anesthetic/contrast agent (P = .005), time required to insert the biopsy needle (P = .02), and distance between contrast tract and final needle position (P = .03). No statistical difference was identified for the angle between the contrast tract and needle position. This difference likely reflects the confidence of the radiologist in identifying the needle location during the procedure. Using a commercially available guide that has a fixed angle can result in a faster, more efficient, and reproducible biopsy technique compared to the freehand technique, especially for those who have less experience in performing sonographically guided biopsies.