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Purpose: After chemotherapy, approximately 50% of patients with metastatic testicular germ cell tumors (GCTs) who undergo retroperitoneal lymph node dissections (RPNLDs) for residual masses have fibrosis. Radiomics uses image processing techniques to extract quantitative textures/features from regions of interest (ROIs) to train a classifier that predicts outcomes. We hypothesized that radiomics would identify patients with a high likelihood of fibrosis who may avoid RPLND. Patients and Methods: Patients with GCT who had an RPLND for nodal masses > 1 cm after first-line platinum chemotherapy were included. Preoperative contrast-enhanced axial computed tomography images of retroperitoneal ROIs were manually contoured. Radiomics features (n = 153) were used to train a radial basis function support vector machine classifier to discriminate between viable GCT/mature teratoma versus fibrosis. A nested 10-fold cross-validation protocol was used to determine classifier accuracy. Clinical variables/restricted size criteria were used to optimize the classifier. Results: Seventy-seven patients with 102 ROIs were analyzed (GCT, 21; teratoma, 41; fibrosis, 40). The discriminative accuracy of radiomics to identify GCT/teratoma versus fibrosis was 72 ± 2.2% (area under the curve [AUC], 0.74 ± 0.028); sensitivity was 56.2 ± 15.0%, and specificity was 81.9 ± 9.0% (P =.001). No major predictive differences were identified when data were restricted by varying maximal axial diameters (AUC range, 0.58 ± 0.05 to 0.74 ± 0.03). The prediction algorithm using clinical variables alone identified an AUC of 0.76. When these variables were added to the radiomics signature, the best performing classifier was identified when axial masses were limited to diameter < 2 cm (accuracy, 88.2 ± 4.4; AUC, 0.80 ± 0.05; P =.02). Conclusion: A predictive radiomics algorithm had a discriminative accuracy of 72% that improved to 88% when combined with clinical predictors. Additional independent validation is required to assess whether radiomics allows patients with a high predicted likelihood of fibrosis to avoid RPLND. [ABSTRACT FROM AUTHOR]

Although a common occurrence, cystic lesions of the pancreatico-biliary tree (PBT) may pose a diagnostic dilemma because they encompass a large number of neoplastic and benign processes with varied clinical symptoms. Knowledge of lesion classification and characterization are essential in making an accurate prospective diagnosis. This is necessary for identifying clinically significant cystic masses, which at times may require invasive intervention from indolent, nonneoplastic lesions, for which surveillance may suffice. Today, there is an arsenal of modalities for assessing the PBT, however, magnetic resonance imaging (MRI) remains at the forefront for characterizing cystic morphology and fluid content, internal septations, solid component, enhancement patterns, as well as assessing the surrounding normal structures. This pictorial review aims to review the spectrum of MRI features, which will aid in the differential diagnoses of cystic lesions of the PBT and mimickers, enabling the radiologist to reach a more confident diagnosis. [ABSTRACT FROM AUTHOR]

Kaposi’s sarcoma was originally described by Moritz Kaposi in 1872 as a rare form of multiple hemorrhagic skin lesions. Today it is well documented as a systemic, multifocal, steadily progressive reticuloendothelial system tumor with a predilection for skin and visceral involvement. It occasionally presents as a visceral disease without skin manifestations. We report a case of Kaposi’s sarcoma of the small bowel in a seropositive patient who presented with acute right lower quadrant pain and was diagnosed with intestinal obstruction with perforation on contrast-enhanced multidetector computed tomography (MDCT). The diagnosis was confirmed as Kaposi’s sarcoma on postoperative histopathological analysis. [ABSTRACT FROM AUTHOR]

Aims: To determine the incidence of natural growth or regression of focal nodular hyperplasia (FNH) in the liver. Material and Methods: We retrospectively included 120 consecutive patients who were diagnosed to have FNH on MRI. The mean follow-up duration was 19 months (range: 6-64 months). There were 25 men and 95 women (age range: 18-80 years; mean: 45 years). There were 167 FNH lesions in the 120 patients. MRI images were retrospectively reviewed for interval growth or regression of FNH. The maximum size of the lesions was measured on axial arterial-phase images of the initial and the last MRI examinations. An interval increase or decrease in diameter of over 10% of the initial diameter was considered as positive growth or regression, respectively. The use of Oral contraceptives was also documented. Results: Interval growth was seen in 25/167 nodules (15%) over 7-48 months (mean: 21 months), with increase in size of 0.2-1.7 cm (mean: 0.6 cm) and percentage change of 10.5-340% (mean: 64%). Interval regression was seen in 13/167 (8%) of nodules over 7-63 months (mean: 22 months), with decrease in size of 0.2-0.9 cm (mean: 0.5 cm) and percentage change of 10.4-60% (mean: 24%).Five of 17 (29%) female patients with growing FNH and 25/78 (32%) female patients with non-growing FNH had a history of intake of oral contraceptives (P=0.83). Conclusions: Although FNH is benign and of no clinical significance, a substantial percentage of FNH shows interval growth or regression on long-term follow-up with MRI. [ABSTRACT FROM AUTHOR]

To describe dynamic 18F-flumethycholine PET (dPET) and dynamic contrast enhancement MR (DCE MR) parameters in localized high-risk prostate cancer (PCa), and determine whether these differ from normal prostate. Furthermore, to determine whether a correlation exists between dPET and DCE MR parameters. 41 consenting patients who underwent prostate DCE MR and dPET were included in this institutionally approved study. Intraprostatic lesions on MR were assigned a PI-RADS v2 score, and focal lesions on PET were documented. All lesions were correlated with pathology. Quantitative and semi-quantitative DCE MR and two-tissue compartmental model dPET parameters were determined and tumor-to-normal gland ratios (T/N) for these parameters were calculated. Finally, dPET and DCE MR correlation was estimated using Spearman correlation coefficients. There were 46 malignant lesions per standard of reference. On dPET, peripheral zone (PZ) tumors had higher K1 (p < 0.001), and a T/N ratio ≥2 was significant (p < 0.001). On DCE MR, the parameters in, kep, Ktrans and quantitative iAUC were higher for PZ and non-PZ tumors than corresponding normal tissue (p < 0.001); for PZ tumors, a T/N ratio ≥ 1.5 for Ktrans and pei was significant (p = 0.0019 and 0.0026, respectively). Moderate Spearman correlation (0.40 < ρ < 0.59) was found between dPET K1 and DCE MR Ktrans and pei. In patients with high-risk PCa, quantitative dPET and DCE-MR parameters in primary tumors differ from normal tissue. Only moderate correlation exists between K1 (dPET) and Ktrans and pei (DCE MR). The incremental value of any of these parameters to PI-RADS v2 warrants further investigation. Unique quantitative and semi-quantitative FCH PET/MR parameters in PCa differ from normal gland, and should be further investigated to determine their potential contribution to PI-RADS v2 in the detection of clinically significant PCa. [ABSTRACT FROM AUTHOR]

BACKGROUND. Current guidelines recommend visual evaluation of coronary artery calcium (CAC) on all nongated noncontrast chest CT examinations. However, chest CT examinations are often performed with contrast material administration. OBJECTIVE. The purpose of our study was to evaluate diagnostic performance, prognostic utility, and interobserver agreement of visual CAC assessment on chest CT performed for other indications. METHODS. This retrospective study included 260 patients (158 men, 102 women; mean age, 60 ± 11 [SD] years) who underwent both nongated chest CT (contrast-enhanced in 116 patients; noncontrast in 144 patients) and cardiac calcium score CT within a 12-month interval. A cardiothoracic radiologist visually assessed CAC on chest CT using an ordinal scale (absent, mild, moderate, or severe). Cardiac CT Agatston calcium scores were quantified according to established guidelines and were categorized as CAC absent (0), mild CAC (1-99), moderate CAC (100-299), or severe CAC (≥ 300). The diagnostic performance of chest CT for the presence of CAC was assessed using cardiac CT as the reference standard. Major adverse cardiac events (MACE) were assessed as a composite of cardiovascular death and myocardial infarction and were evaluated using Cox proportional hazards models. A second cardiothoracic radiologist performed visual CAC assessments in a random subset of 50 chest CT examinations to assess interob-server agreement. RESULTS. For the presence of any CAC on cardiac CT, contrast-enhanced and non-contrast chest CT had sensitivity of 83% (62/75) and 89% (85/95) ( p = .20) and specificity of 100% (41/41) and 100% (49/49) ( p = .99). CAC present on cardiac CT was misclassified as absent on 13 contrast-enhanced and 10 noncontrast chest CT examinations; Agatston score was less than 30 in all such patients, and none experienced any MACE. The visual ordinal CAC score was associated with MACE for contrast-enhanced chest CT (hazard ratio [HR] = 4.5 [95% CI, 1.2-16.4], p = .02) and noncontrast chest CT (HR = 3.4 [95% CI, 1.5-7.8], p = .003). Interobserver agreement was excellent for contrast-enhanced (κ = 0.89) and noncontrast (κ = 0.95) chest CT. CONCLUSION. Visual ordinal CAC assessment on both contrast-enhanced and non-contrast chest CT has high diagnostic performance, prognostic utility, and interobserver agreement. CLINICAL IMPACT. Routine reporting of CAC on all chest CT examinations regardless of clinical indication and contrast material administration could identify a large number of patients with previously unknown CAC who might benefit from preventive treatment.

Purpose: To examine the prognostic implication of fractional flow reserve (FFR) derived from coronary CT (FFR CT ) in routine clinical practice., Materials and Methods: Patients referred for FFR CT analysis at a single center between October 2015 and June 2017 were retrospectively included and followed up for rates of invasive angiography and clinical events. Two hundred seven patients underwent successful FFR CT analysis with seven lost to follow-up, leaving 200 (mean age ± standard deviation, 62.4 years ± 10.0; 49 [24.5%] women) patients for analysis. At coronary CT angiography, patients were categorized as having significant stenosis (SS) in the presence of a diameter stenosis greater than or equal to 50% (hereafter, SS positive) and flow limitation in the presence of a postlesion (that is, FFR CT measured 2 cm to the distal aspect of the lesion) FFR CT less than 0.80 (hereafter, FFR CT positive). Vessel-oriented clinical events (VOCEs) were defined as vessel-related late revascularization (>90 days), myocardial infarction, and cardiac mortality., Results: At CT angiography, 130 (65%) studies were SS positive and 63 (31.5%) were FFR CT positive. At median follow-up of 477 days (range, 252-859 days), there were 26 VOCE end points in 22 patients: 22 revascularizations and four nonfatal myocardial infarctions. VOCE end points occurred in zero of 58 (0%) of SS-negative and FFR CT negative patients, in eight of 79 (10.1%) of SS-positive and FFR CT -negative patients, in zero of 12 (0%) of SS-negative and FFR CT -positive patients, and in 18 of 51 (35.3%) of SS-positive and FFR CT -positive patients (log-rank χ 2 = 30.1; P < .001). At multivariable Cox regression, both FFR CT (hazard ratio per 0.1 decrease, 1.54 [95% confidence interval: 1.1, 2.2] P = .013) and stenosis (hazard ratio per unit increase, 2.16 [95% confidence interval: 1.25, 3.72] P = .006) were independently associated with VOCE., Conclusion: Stenosis and FFR CT are independent predictors of intermediate-term outcomes. In the absence of a stenosis greater than 50%, a positive FFR CT result is not associated with an increased intermediate risk.© RSNA, 2019 Supplemental material is available for this article. See also commentary by Fairbairn and Bull in this issue., Competing Interests: Disclosures of Conflicts of Interest: C.G.M. disclosed no relevant relationships. S.L.S. disclosed no relevant relationships. R.J.A.W. disclosed no relevant relationships. S.H. disclosed no relevant relationships. S.A.R. disclosed no relevant relationships. D.T.M. disclosed no relevant relationships. P.B. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: is a consultant for Circle Cardiovascular Imaging, Edwards Lifesciences, Gore, Neovasc, and Tendyne. Other relationships: disclosed no relevant relationships. A.A.A. disclosed no relevant relationships J.H. disclosed no relevant relationships. A.A.T. disclosed no relevant relationships. M.G.Z. disclosed no relevant relationships. J.W.L.Y. disclosed no relevant relationships. B.L.N. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: has grants/grants pending with HeartFlow and Siemens; received payment for travel/accommodations/meeting expenses unrelated to activities listed from HeartFlow. Other relationships: disclosed no relevant relationships. J.A.L. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: is a consultant for Circle Cardiovascular Imaging and HeartFlow; has grants/grants pending with GE Healthcare; holds stock/stock options in Circle Cardiovascular Imaging and HeartFlow. Other relationships: disclosed no relevant relationships. J.R.W.M. disclosed no relevant relationships., (2019 by the Radiological Society of North America, Inc.)

Objective: The purpose of this study was to determine whether integrated 18 F-fluorocholine (FCH) PET whole-body MRI (PET/WBMRI) depicts lymph node and distant metastases in patients with high-risk prostate cancer more frequently than does conventional staging., Subjects and Methods: A prospective study included 58 patients with untreated high-risk prostate cancer. After conventional staging (CT and bone scintigraphy), patients underwent FCH PET/WBMRI (n = 10) or FCH PET/CT and WBMRI (n = 48). Metastatic sites and disease stage were recorded for each modality (conventional imaging, PET, WBMRI, and PET/WBMRI) and compared with a standard of reference (histopathologic examination, imaging, and clinical follow-up) and early clinical outcomes., Results: In the detection of metastases, PET had significantly higher sensitivity (72/77 [93.5%]) than conventional imaging (49/77 [63.6%]; p < 0.001) and WBMRI (56/77 [72.7%]; p = 0.002). There was a trend toward improved detection with PET/WBMRI (77/77 [100%]) compared with PET alone (p = 0.059). For correct NM staging, PET and PET/WBMRI performed better than conventional imaging (p = 0.002) and WBMRI (p = 0.008). Twelve of 56 patients (21.4%) had early biochemical failure after radical treatment (median, 7 months; range, 1-20 months). This rate was higher for patients with M1a or M1b disease at PET/WBMRI than for others, but this finding did not reach statistical significance (4/8 [50%] vs 8/48 [16.7%]; p = 0.055)., Conclusion: In patients with high-risk prostate cancer, FCH PET and FCH PET/WBMRI depict significantly more metastatic lesions than do conventional imaging and WBMRI. Stage determined with PET/WBMRI may correlate with early outcomes.

Purpose: To investigate whether volumetrically derived apparent diffusion coefficient (ADC) from pretreatment diffusion-weighted (DW) magnetic resonance (MR) imaging is associated with disease recurrence in women with locally advanced cervical cancer treated with chemotherapy and radiation therapy., Materials and Methods: An ethics board-approved, retrospective study was conducted in 85 women with stage IB-IVA cervical cancer treated with chemo- and radiation therapy in 2009-2013. All patients underwent MR imaging for staging, including T2-weighted and DW MR imaging series, by using a 1.5- or 3.0-T imager. The mean, median, 75th, 90th, and 95th percentile ADCs (ADCmean, ADC50, ADC75, ADC90, and ADC95, respectively) of all voxels that comprised each tumor were extracted and normalized to the mean urine ADC (nADCmean, nADC50, nADC75, nADC90, and nADC95, respectively) to reduce variability. The primary outcome was disease-free survival (DFS). Uni- and multivariable Cox regression analyses were used to evaluate the association of ADC parameters and relevant clinical variables with DFS., Results: Of the 85 women included, 62 were free of disease at last follow-up. Median follow-up was 37 months (range, 5-68 months). Significant variables at univariable analysis included T2-weighted derived tumor diameter, para-aortic nodal involvement, advanced stage, ADC90 and ADC95, nADC75, nADC90, and nADC95. Normalized parameters were more highly associated (hazard ratio per 0.01 increase in normalized ADC, 0.91-0.94; P < .04). Because nADC75, nADC90, and nADC95 were highly correlated, only nADC95 (which had the lowest P value) was included in multivariable analysis. At multivariable analysis, absolute and normalized ADC95 remained associated with DFS (hazard ratio, 0.90-0.98; P < .05)., Conclusion: The volumetric ADC95 may be a useful imaging metric to predict treatment failure in patients with locally advanced cervical cancer treated with chemo- and radiation therapy.

Objective: The objective of our study was to assess the association between colorectal liver metastases and intrahepatic bile duct dilatation and compare its frequency with the frequency of intrahepatic bile duct dilatation in other common noncolorectal metastases and hepatocellular carcinoma (HCC)., Materials and Methods: A retrospective review of the radiology database was performed to obtain the records of patients who underwent CT for staging of histologically proven colorectal carcinoma (n = 1,000), noncolorectal carcinomas (n = 1,000), and HCC (n = 226). The CT scans of the 2,226 patients were reviewed for the presence of liver metastases and masses, the presence of intrahepatic bile duct dilatation directly related to the masses, the size of the largest lesion, and the associated caliber of the dilated intrahepatic bile duct., Results: Of the 297 patients with colorectal liver metastases, 49 (16.5%) had intrahepatic bile duct dilatation, whereas of the 263 patients with noncolorectal liver metastases, only eight (3%) had dilated ducts. Thirteen (5.7%) of the 226 patients with HCC had intrahepatic bile duct dilatation. Intrahepatic bile duct dilatation was present in significantly more patients with colorectal liver metastases (p < 0.05) than those with noncolorectal and HCC metastases. The mean sizes of the lesions and mean caliber of the dilated bile duct from colorectal metastases, noncolorectal metastases, and HCC were 5.3, 3.9, and 5.6 cm, respectively, and 5.1, 4.6, and 4.8 mm, respectively. Overall lesion size irrespective of diagnosis had no significant correlation with the probability of bile duct dilatation (p = 0.16; odds ratio = 1.08; 95% CI, 0.97-1.20). Lesion size also did not have a significantly different effect on the probability of dilatation for the three diagnoses (p = 0.71). The caliber of bile duct dilatation did not significantly differ among the three groups of patients by diagnosis (p = 0.70)., Conclusion: Colorectal liver metastases have a significantly higher tendency to cause intrahepatic bile duct dilatation than noncolorectal metastases and HCC due to the characteristic features, such as cholangiocarcinoma, of intrabiliary growth. This association has important diagnostic, surgical, and prognostic implications that make it necessary to highlight this finding while communicating with clinical colleagues.