Deep learning supports the differentiation of alcoholic and other-than-alcoholic cirrhosis based on MRI.

Although CT and MRI are standard procedures in cirrhosis diagnosis, differentiation of etiology based on imaging is not established. This proof-of-concept study explores the potential of deep learning (DL) to support imaging-based differentiation of the etiology of liver cirrhosis. This retrospective, monocentric study included 465 patients with confirmed diagnosis of (a) alcoholic (n = 221) and (b) other-than-alcoholic (n = 244) cirrhosis. Standard T2-weighted single-slice images at the caudate lobe level were randomly split for training with fivefold cross-validation (85%) and testing (15%), balanced for (a) and (b). After automated upstream liver segmentation, two different ImageNet pre-trained convolutional neural network (CNN) architectures (ResNet50, DenseNet121) were evaluated for classification of alcohol-related versus non-alcohol-related cirrhosis. The highest classification performance on test data was observed for ResNet50 with unfrozen pre-trained parameters, yielding an area under the receiver operating characteristic curve of 0.82 (95% confidence interval (CI) 0.71-0.91) and an accuracy of 0.75 (95% CI 0.64-0.85). An ensemble of both models did not lead to significant improvement in classification performance. This proof-of-principle study shows that deep-learning classifiers have the potential to aid in discriminating liver cirrhosis etiology based on standard MRI.

Combination of Fat-Free Muscle Index and Total Spontaneous Portosystemic Shunt Area Identifies High-Risk Cirrhosis Patients.

Background: Sarcopenia and spontaneous portosystemic shunts (SPSSs) are common complications of liver cirrhosis, and both are associated with higher rates of hepatic encephalopathy (HE) development in these patients. This study aimed to evaluate the simultaneous impact of skeletal muscle mass and spontaneous portosystemic shunting, measured from routine diagnostic CT on outcomes in patients with liver cirrhosis. Methods: Retrospective analysis of patients with cirrhosis. Skeletal muscle mass [including fat-free muscle index (FFMI) as a surrogate for sarcopenia] and total cross-sectional spontaneous portosystemic shunt area (TSA) were quantified from CT scans. The primary endpoint was the development of HE, while the secondary endpoint was 1-year mortality. Results: One hundred fifty-six patients with liver cirrhosis were included. Patients with low (L-) FFMI and large (L-)TSA showed higher rates of HE development. In multivariable analysis, L-FFMI and L-TSA were independent predictors of HE development (L-FFMI HR = 2.69, CI 1.22-5.93; L-TSA, HR = 2.50, CI = 1.24-4.72) and 1-year mortality (L-FFMI, HR = 7.68, CI 1.75-33.74; L-TSA, HR = 3.05, CI 1.32-7.04). The simultaneous presence of L-FFMI and L-TSA exponentially increased the risk of HE development (HR 12.79, CI 2.93-55.86) and 1-year mortality (HR 13.66, CI 1.75-106.50). An easy sequential algorithm including FFMI and TSA identified patients with good, intermediate, and poor prognoses. Conclusion: This study indicates synergy between low skeletal muscle mass and large TSA to predict exponentially increased risk of HE development and mortality in liver cirrhosis. Simultaneous screening for sarcopenia and TSA from routine diagnostic CT may help to improve the identification of high-risk patients using an easy-to-apply algorithm. Clinical Trial registration: [ClinicalTrials.gov], identifier [NCT03584204].

Cranial stent position is independently associated with the development of TIPS dysfunction.

Complications of portal hypertension can be treated with transjugular intrahepatic portosystemic shunt (TIPS) in selected patients. TIPS dysfunction is a relevant clinical problem. This study investigated the prognostic value of two-dimensional (2D) TIPS geometry for the development of TIPS dysfunction. Three hundred and seven patients undergoing TIPS procedure between 2014 and 2019 were analyzed in this monocentric retrospective study. 2D angiograms from the patients with and without TIPS dysfunction were reviewed to determine geometric characteristics including insertion and curve angles and the location of the stent. Primary outcome was the development of TIPS dysfunction. A total of 70 patients developed TIPS dysfunction and were compared to the dysfunction-free (n = 237) patients. The position of the cranial stent end in the hepatic vein and the persistence of spontaneous portosystemic shunts were significantly associated with the development of TIPS dysfunction. Among significant parameters in univariable regression analysis (portal vein-pressure after TIPS, Child-Pugh Score before TIPS, MELD before TIPS and white blood cell count before TIPS), multivariable models showed cranial stent position (p = 0.027, HR 2.300, 95% CI 1.101-4.806) and SPSS embolization (p = 0.006, HR 0.319, 95% CI 0.140-0.725) as the only predictors of TIPS dysfunction. This monocentric study demonstrates that the position of the cranial stent end is independently associated with the development of TIPS dysfunction. The distance of the cranial stent end to the IVC at the time of TIPS placement should be less than 1 cm in 2D angiography.

Diagnostic Accuracy of Quantitative Imaging Biomarkers in the Differentiation of Benign and Malignant Vertebral Lesions : Combination of Diffusion-Weighted and Proton Density Fat Fraction Spine MRI.

PURPOSE: To compare and combine the diagnostic performance of the apparent diffusion coefficient (ADC) derived from diffusion-weighted imaging (DWI) and proton density fat fraction (PDFF) derived from chemical-shift encoding (CSE)-based water-fat magnetic resonance imaging (MRI) for distinguishing benign and malignant vertebral bone marrow lesions (VBML). METHODS: A total of 55 consecutive patients with 53 benign (traumatic, inflammatory and primary) and 36 malignant (metastatic and hematologic) previously untreated VBMLs were prospectively enrolled in this IRB-approved study and underwent sagittal DWI (single-shot spin-echo echo-planar with multi-slice short TI inversion recovery fat suppression) and CSE-based MRI (gradient-echo 6­point modified Dixon) in addition to routine clinical spine MRI at 1.5 T or 3.0 T. Diagnostic reference standard was established according to histopathology or imaging follow-up. The ADC = ADC (0, 800) and PDFF = fat / (water + fat) were calculated voxel-wise and examined for differences between benign and malignant lesions. RESULTS: The ADC and PDFF values of malignant lesions were significantly lower compared to benign lesions (mean ADC 861â€¯× 10-6 mm2/s vs. 1323â€¯× 10-6 mm2/s, p < 0.001; mean PDFF 3.1% vs. 28.2%, p < 0.001). The areas under the curve (AUC) and diagnostic accuracies were 0.847 (p < 0.001) and 85.4% (cut-off at 1084.4â€¯× 10-6 mm2/s) for ADC and 0.940 (p < 0.001) and 89.9% for PDFF (cut-off at 7.8%), respectively. The combined use of ADC and PDFF improved the diagnostic accuracy to 96.6% (malignancy if ADC ≤ 1118.2â€¯× 10-6 mm2/s and PDFF ≤ 20.0%, otherwise benign). CONCLUSION: Quantitative evaluation of both ADC and PDFF was useful in differentiating benign VBMLs from malignancy. The combination of ADC and PDFF improved the diagnostic performance and yielded high diagnostic accuracy for the differentiation of benign and malignant VBMLs.

Proton density fat fraction MRI of vertebral bone marrow: Accuracy, repeatability, and reproducibility among readers, field strengths, and imaging platforms.

BACKGROUND: Chemical shift-encoding based water-fat MRI is an emerging method to noninvasively assess proton density fat fraction (PDFF), a promising quantitative imaging biomarker for estimating tissue fat concentration. However, in vivo validation of PDFF is still lacking for bone marrow applications. PURPOSE: To determine the accuracy and precision of MRI-determined vertebral bone marrow PDFF among different readers and across different field strengths and imager manufacturers. STUDY TYPE: Repeatability/reproducibility. SUBJECTS: Twenty-four adult volunteers underwent lumbar spine MRI with one 1.5T and two different 3.0T MR scanners from two vendors on the same day. FIELD STRENGTH/SEQUENCE: 1.5T and 3.0T/3D spoiled-gradient echo multipoint Dixon sequences. ASSESSMENT: Two independent readers measured intravertebral PDFF for the three most central slices of the L1-5 vertebral bodies. Single-voxel MR spectroscopy (MRS)-determined PDFF served as the reference standard for PDFF estimation. STATISTICAL TESTS: Accuracy and bias were assessed by Pearson correlation, linear regression analysis, and Bland-Altman plots. Repeatability and reproducibility were evaluated by Wilcoxon signed rank test, Friedman test, and coefficients of variation. Intraclass correlation coefficients were used to validate intra- and interreader as well as intraimager agreements. RESULTS: MRI-based PDFF estimates of lumbar bone marrow were highly correlated (r2 = 0.899) and accurate (mean bias, -0.6%) against the MRS-determined PDFF reference standard. PDFF showed high linearity (r2 = 0.972-0.978) and small mean bias (0.6-1.5%) with 95% limits of agreement within ±3.4% across field strengths, imaging platforms, and readers. Repeatability and reproducibility of PDFF were high, with the mean overall coefficient of variation being 0.86% and 2.77%, respectively. The overall intraclass correlation coefficient was 0.986 as a measure for an excellent interreader agreement. DATA CONCLUSION: MRI-based quantification of vertebral bone marrow PDFF is highly accurate, repeatable, and reproducible among readers, field strengths, and MRI platforms, indicating its robustness as a quantitative imaging biomarker for multicentric studies. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:1762-1772.

Short-Term Measurement Repeatability of a Simplified Intravoxel Incoherent Motion (IVIM) Analysis for Routine Clinical Diffusion-Weighted Imaging in Malignant Liver Lesions and Liver Parenchyma at 1.5 T.

OBJECTIVES: To evaluate measurement repeatability of parameters derived from simplified intravoxel incoherent motion (IVIM) analysis of diffusion-weighted imaging (DWI) using 3 b-values. MATERIALS AND METHODS: 24 patients (16 male, 8 female, mean age: 67 years) with hepatic malignancy (HCC: 10, metastases: 14) underwent 29 liver MRI examinations at 1.5 T. Respiratory-triggered DWI (b = 0, 50, 800 s/mm2) was acquired twice. Parameter maps of the apparent diffusion coefficient ADC(0,800), estimated diffusion coefficient D' and perfusion fraction f' were calculated. Measurement repeatability for a region of interest (ROI) placed in one lesion and liver parenchyma per lobe was assessed by intra-session variation coefficients (CV). RESULTS: 86 ROIs (43 lesions, 43 parenchymas) were analyzed. Parameters did not significantly differ between measurements. Repeatability was excellent for ADC(0,800) and D' and good for f' in parenchyma (CVs: 7.3 %, 9.8 %, 13.0 %) and lesions (CVs: 7.5 %, 8.5 %, 11.0 %). Differences in CV-values between liver and lesions were not significant. Repeatability was better for the right than for the left lobe by tendency, for parenchyma (CVs: 6.4 % vs 8.4 %, 8.8 % vs 10.9 %, 10.5 % vs 16.0 %) and for lesions (CVs: 6.9 % vs 8.1 %, 7.5 % vs 9.5 %, 9.5 % vs 12.7 %). CONCLUSION: Measurement repeatability is excellent for ADC(0,800) and D' values and good for f' values using the simplified IVIM approach, both in lesions and liver parenchyma. Repeatability was better for lesions in the right compared to the left liver lobe. KEY POINTS: · Repeatability obtained by a simplified IVIM analysis approach is good to excellent.. · Repeatability is better for the right than for the left liver lobe.. · The simplified approach may be helpful in diagnosing and monitoring liver malignancies.. CITATION FORMAT: · Pieper CC, Sprinkart AM, Kukuk GM et al. Short-Term Measurement Repeatability of a Simplified Intravoxel Incoherent Motion (IVIM) Analysis for Routine Clinical Diffusion-Weighted Imaging in Malignant Liver Lesions and Liver Parenchyma at 1.5T. Fortschr Röntgenstr 2019; 191: 199 - 208.

Evaluation of Exponential ADC (eADC) and Computed DWI (cDWI) for the Detection of Prostate Cancer.

PURPOSE: To directly compare different methods proposed for enhanced conspicuity and discriminability of prostate cancer on diffusion-weighted imaging (DWI) and to compare the results to original DWI images and conventional apparent diffusion coefficient (ADC) maps. MATERIALS AND METHODS: Clinical routine prostate DWI datasets (b = 0, 50, 800 s/mm², acquired at a field strength of 3 T) of 104 consecutive patients with subsequent MR-guided prostate biopsy were included in this retrospective study. For each dataset exponential ADC maps (eADC), computed DWI images (cDWI), and additionally eADC maps for computed b-values of 2000 and 3000 s/mm² were generated (c_eADC). For each of 123 lesions, the contrast (CR) and contrast-to-noise ratio (CNR) were determined. Differences in the CR and CNR of malignant lesions (n = 83) between the different image types and group differences between benign (n = 40), low-risk (n = 53) and high-risk (n = 30) lesions were assessed by repeated measures ANOVA and one-way ANOVA with post-hoc tests. The ability to differentiate between benign and malignant and between low-risk and high-risk lesions was assessed by receiver operating characteristic (ROC) curve analyses. RESULTS: The CR and CNR were higher for computed DWI and related c_eADC at b = 3000 s/mm² and 2000 s/mm² compared to original DWI, conventional ADC and standard eADC. For differentiation of benign and malignant lesions, conventional ADC and CR of conventional ADC were best suited. For discrimination of low-risk from high-risk lesions, the CR of c_eADC was best suited followed by the CR of cDWI. CONCLUSION: Computed cDWI or related c_eADC maps at b-values between 2000 and 3000 s/mm2 were superior to the original DWI, conventional ADC and eADC in the detection of prostate cancer. KEY POINTS: · Prostate cancer can appear inconspicuous on original DWI800 images. · Computed DWI images at b = 2000 - 3000 s/mm² improve lesion-to-normal-tissue contrast in prostate cancer. · Contrast in computed DWI is superior to ADC and eADC at b = 800 s/mm². CITATION FORMAT: · Sprinkart AM, Marx C, Träber F et al. Evaluation of Exponential ADC (eADC) and Computed DWI (cDWI) for the Detection of Prostate Cancer. Fortschr Röntgenstr 2018; 190: 758 - 766.

Quantitative and Qualitative Assessment of Pulmonary Emphysema with T2-Weighted PROPELLER MRI in a High-Risk Population Compared to Low-Dose CT.

PURPOSE: To determine the suitability of T2-weighted PROPELLER MRI for the assessment of pulmonary emphysema. MATERIALS AND METHODS: 60 participants in a lung cancer screening program (30 subjects with pulmonary emphysema, and 30 control subjects without emphysema) were included for this retrospective study. All subjects were examined with low-dose CT (LDCT) and MRI within the screening program. The use of a T2-weighted PROPELLER sequence for the assessment of emphysema was analyzed and correlated with the results of LDCT. The presence and the extent of pulmonary emphysema were first assessed qualitatively using a three-point score, and then quantitatively with a semi-automated software program to obtain emphysema indices. RESULTS: All 30 cases with pulmonary emphysema were accurately detected by MRI. There were 3 cases with emphysema according to MRI without emphysematous changes on LDCT (false-positive results). The qualitative scores as well as the emphysema indices were significantly higher in the emphysema group compared to the control group for MRI and LDCT (p < 0.001). Both the scores and the indices correlated significantly between MRI and LDCT (qualitative score of severity: r = 0.912/p < 0.001 in the emphysema group and r = 0.668/p < 0.001 in the control group; emphysema index: r = 0.960/p < 0.001 in the emphysema group and r = 0.746/p < 0.001 in the control group). CONCLUSION: The presence and the extent of pulmonary emphysema may be assessed qualitatively and quantitatively by T2-weighted PROPELLER MRI with very good correlation to LDCT. KEY POINTS: · T2-weighted PROPELLER MRI may be suitable for the assessment of pulmonary emphysema.. · There was significant correlation between MRI and LDCT regarding qualitative scores and quantitative emphysema indices in our study with correlation coefficients for different subgroups ranging from r = 0.668 to r = 0.960.. · T2-weighted PROPELLER MRI may have the potential to be used for follow-up examinations in patients with severe emphysema to avoid radiation exposure of repeated CTs.. CITATION FORMAT: · Meier-Schroers M, Sprinkart AM, Becker M et al. Quantitative and Qualitative Assessment of Pulmonary Emphysema with T2-Weighted PROPELLER MRI in a High-Risk Population Compared to Low-Dose CT. Fortschr Röntgenstr 2018; 190: 733 - 739.

Revised PROPELLER for T2-weighted imaging of the prostate at 3 Tesla: impact on lesion detection and PI-RADS classification.

PURPOSE: To evaluate revised PROPELLER (RevPROP) for T2-weighted imaging (T2WI) of the prostate as a substitute for turbo spin echo (TSE). MATERIALS AND METHODS: Three-Tesla MR images of 50 patients with 55 cancer-suspicious lesions were prospectively evaluated. Findings were correlated with histopathology after MRI-guided biopsy. T2 RevPROP, T2 TSE, diffusion-weighted imaging, dynamic contrast enhancement, and MR-spectroscopy were acquired. RevPROP was compared to TSE concerning PI-RADS scores, lesion size, lesion signal-intensity, lesion contrast, artefacts, and image quality. RESULTS: There were 41 carcinomas in 55 cancer-suspicious lesions. RevPROP detected 41 of 41 carcinomas (100%) and 54 of 55 lesions (98.2%). TSE detected 39 of 41 carcinomas (95.1%) and 51 of 55 lesions (92.7%). RevPROP showed fewer artefacts and higher image quality (each p < 0.001). No differences were observed between single and overall PI-RADS scores based on RevPROP or TSE (p = 0.106 and p = 0.107). Lesion size was not different (p = 0.105). T2-signal intensity of lesions was higher and T2-contrast of lesions was lower on RevPROP (each p < 0.001). CONCLUSION: For prostate cancer detection RevPROP is superior to TSE with respect to motion robustness, image quality and detection rates of lesions. Therefore, RevPROP might be used as a substitute for T2WI. KEY POINTS: • Revised PROPELLER can be used as a substitute for T2-weighted prostate imaging. • Revised PROPELLER detected more carcinomas and more suspicious lesions than TSE. • Revised PROPELLER showed fewer artefacts and better image quality compared to TSE. • There were no significant differences in PI-RADS scores between revised PROPELLER and TSE. • The lower T2-contrast of revised PROPELLER did not impair its diagnostic quality.

In-bore transrectal MRI-guided prostate biopsies: Are there risk factors for complications?

PURPOSE: To systematically analyze risk factors for complications of in-bore transrectal MRI-guided prostate biopsies (MRGB). MATERIALS AND METHODS: 90 patients, who were scheduled for MRGB were included for this study. Exclusion criteria were coagulation disorders, therapy with anticoagulant drugs, and acute infections of the urinary and the lower gastrointestinal tract. Directly after, one week and one year after the biopsy, we assessed biopsy related complications (e.g. hemorrhages or signs of prostatitis). Differences between patients with and without complications were analyzed regarding possible risk factors: age, prostate volume, number of taken samples, biopsy duration, biopsy of more than one lesion, diabetes, arterial hypertension, hemorrhoids, benign prostate hyperplasia, carcinoma or prostatitis (according to histopathological analysis), and lesion localization. Complications were classified according to the Clavien-Dindo classification. RESULTS: We observed 15 grade I complications in 90 biopsies (16.7%) with slight hematuria in 9 cases (10%), minor vasovagal reactions in 4 cases (4.4%), and urinary retention and positioning-related facial dysesthesia in 1 case each (1.1%). One patient showed acute prostatitis requiring antibiotics as the only grade II complication (1.1%). There were no adverse events that occurred later than one week. Complications grade III or higher such as pelvic abscesses, urosepsis or severe hemorrhages were not seen. There were no significant associations between the assessed risk factors and biopsy-related complications. CONCLUSION: In-bore transrectal MRI-guided prostate biopsies can be considered safe procedures in the diagnosis of prostate cancer with very low complication rates. There seem to be no risk factors for complications.

The value of intravoxel incoherent motion model-based diffusion-weighted imaging for outcome prediction in resin-based radioembolization of breast cancer liver metastases.

PURPOSE: To evaluate prognostic values of clinical and diffusion-weighted magnetic resonance imaging-derived intravoxel incoherent motion (IVIM) parameters in patients undergoing primary radioembolization for metastatic breast cancer liver metastases. SUBJECTS AND METHODS: A total of 21 females (mean age 54 years, range 43-72 years) with liver-dominant metastatic breast cancer underwent standard liver magnetic resonance imaging (1.5 T, diffusion-weighted imaging with b-values of 0, 50, and 800 s/mm(2)) before and 4-6 weeks after radioembolization. The IVIM model-derived estimated diffusion coefficient D' and the perfusion fraction f' were evaluated by averaging the values of the two largest treated metastases in each patient. Kaplan-Meier and Cox regression analyses for overall survival (OS) were performed. Investigated parameters were changes in f'- and D'-values after therapy, age, sex, Eastern Cooperative Oncology Group (ECOG) status, grading of primary tumor, hepatic tumor burden, presence of extrahepatic disease, baseline bilirubin, previous bevacizumab therapy, early stasis during radioembolization, chemotherapy after radioembolization, repeated radioembolization and Response Evaluation Criteria in Solid Tumors (RECIST) response at 6-week follow-up. RESULTS: Median OS after radioembolization was 6 (range 1.5-54.9) months. In patients with therapy-induced decreasing or stable f'-values, median OS was significantly longer than in those with increased f'-values (7.6 [range 2.6-54.9] vs 2.6 [range 1.5-17.4] months, P<0.0001). Longer median OS was also seen in patients with increased D'-values (6 [range 1.6-54.9] vs 2.8 [range 1.5-17.4] months, P=0.008). Patients with remission or stable disease (responders) according to RECIST survived longer than nonresponders (7.2 [range 2.6-54.9] vs 2.6 [range 1.5-17.4] months, P<0.0001). An ECOG status ≤1 resulted in longer median OS than >1 (7.6 [range 2.6-54.9] vs 1.7 [range 1.5-4.5] months, P<0.0001). Pretreatment IVIM parameters and the other clinical characteristics were not associated with OS. Classification by f'-value changes and ECOG status remained as independent predictors of OS on multivariate analysis, while RECIST response and D'-value changes did not predict survival. CONCLUSION: Following radioembolization of breast cancer liver metastases, early changes in the IVIM model-derived perfusion fraction f' and baseline ECOG score were predictive of patient outcome, and may thus help to guide treatment strategy.

Intravoxel Incoherent Motion Diffusion-Weighted MR Imaging for Prediction of Early Arterial Blood Flow Stasis in Radioembolization of Breast Cancer Liver Metastases.

PURPOSE: To retrospectively evaluate predictive value of intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) for early arterial blood flow stasis during transarterial radioembolization (TARE) of liver dominant breast metastases (LdBM). MATERIALS AND METHODS: Preinterventional 1.5T DWI (b0, b1, b2 = 0, 50, 800 s/mm(2)) data for 28 liver lobes of 18 female patients treated by resin-based radioembolization (10 bilobar and 8 unilobar treatments) were analyzed. Apparent diffusion coefficient (ADC) (0, 800) and an estimation of the true diffusion coefficient D' and of the perfusion fraction f' were calculated for the 2 largest metastases. Response rate at 3 months and survival were analyzed. Procedures without full dose application because of early stasis were assigned to group A (n = 15), and procedures with full dose application were assigned to group B (n = 13). RESULTS: Metastases in group A showed significantly lower f' (0.035 ± 0.018 vs 0.076 ± 0.015, P < .0001) and a trend toward lower ADC(0, 800) with values given in 10(-6) mm(2)/s (1,066 ± 141 vs 1,189 ± 176, P = .051); no group difference was shown for D'. Groups were best discriminated by weighted mean f' values of the 2 largest metastases with accuracy of 100%. Mean tumor diameter before and after TARE was 51 mm ± 18 and 50 mm ± 24 in group A and 47 mm ± 27 and 48 mm ± 32 for group B. Imaging response did not differ between groups (P = .545). Overall survival did not differ significantly between group A (230 d) and B (155 d) (P = .124). CONCLUSIONS: Perfusion-sensitive IVIM parameter f' may predict early blood flow stasis in patients undergoing TARE for LdBM. Determination of this parameter before intervention may increase awareness of the interventionalist and increase safety of microsphere administration.

Differentiation of prostatitis and prostate cancer using the Prostate Imaging-Reporting and Data System (PI-RADS).

PURPOSE: To determine if prostate cancer (PCa) and prostatitis can be differentiated by using PI-RADS. MATERIALS AND METHODS: 3T MR images of 68 patients with 85 cancer suspicious lesions were analyzed. The findings were correlated with histopathology. T2w imaging (T2WI), diffusion weighted imaging (DWI), dynamic contrast enhancement (DCE), and MR-Spectroscopy (MRS) were acquired. Every lesion was given a single PI-RADS score for each parameter, as well as a sum score and a PI-RADS v2 score. Furthermore, T2-morphology, ADC-value, perfusion type, citrate/choline-level, and localization were evaluated. RESULTS: 44 of 85 lesions showed PCa (51.8%), 21 chronic prostatitis (24.7%), and 20 other benign tissue such as hyperplasia or fibromuscular tissue (23.5%). The single PI-RADS score for T2WI, DWI, DCE, as well as the aggregated score including and not including MRS, and the PI-RADS v2-score were all significantly higher for PCa than for prostatitis or other tissue (p<0.001). The single PI-RADS score for MRS and the PI-RADS sum score including MRS were significantly higher for prostatitis than for other tissue (p=0.029 and p=0.020), whereas the other parameters were not different. Prostatitis usually presented borderline pathological PI-RADS scores, showed restricted diffusion with ADC≥900mm(2)/s in 100% of cases, was more often indistinctly hypointense on T2WI (66.7%), and localized in the transitional zone (57.1%). An ADC≥900mm(2)/s achieved the highest predictive value for prostatitis (AUC=0.859). CONCLUSION: Prostatitis can be differentiated from PCa using PI-RADS, since all available parameters are more distinct in cases of cancer. However, there is significant overlap between prostatitis and other benign findings, thus PI-RADS is only suitable to a limited extent for the primary assessment of prostatitis. Restricted diffusion with ADC≥900mm(2)/s is believed to be a good indicator for prostatitis. MRS can help to distinguish between prostatitis and other tissue.

Extraretinal induced visual sensations during IMRT of the brain.

BACKGROUND: We observed visual sensations (VSs) in patients undergoing intensity modulated radiotherapy (IMRT) of the brain without the beam passing through ocular structures. We analyzed this phenomenon especially with regards to reproducibility, and origin. METHODS AND FINDINGS: Analyzed were ten consecutive patients (aged 41-71 years) with glioblastoma multiforme who received pulsed IMRT (total dose 60Gy) with helical tomotherapy (TT). A megavolt-CT (MVCT) was performed daily before treatment. VSs were reported and recorded using a triggered event recorder. The frequency of VSs was calculated and VSs were correlated with beam direction and couch position. Subjective patient perception was plotted on an 8x8 visual field (VF) matrix. Distance to the orbital roof (OR) from the first beam causing a VS was calculated from the Dicom radiation therapy data and MVCT data. During 175 treatment sessions (average 17.5 per patient) 5959 VSs were recorded and analyzed. VSs occurred only during the treatment session not during the MVCTs. Plotting events over time revealed patient-specific patterns. The average cranio-caudad extension of VS-inducing area was 63.4mm (range 43.24-92.1mm). The maximum distance between the first VS and the OR was 56.1mm so that direct interaction with the retina is unlikely. Data on subjective visual perception showed that VSs occurred mainly in the upper right and left quadrants of the VF. Within the visual pathways the highest probability for origin of VSs was seen in the optic chiasm and the optic tract (22%). CONCLUSIONS: There is clear evidence that interaction of photon irradiation with neuronal structures distant from the eye can lead to VSs.

Postinterventional passive expansion of partially dilated transjugular intrahepatic portosystemic shunt stents.

PURPOSE: To investigate passive transjugular intrahepatic portosystemic shunt (TIPS) stent expansion in patients with intentional "underdilation" (eg, 10-mm stent, 8-mm balloon) during TIPS creation. MATERIALS AND METHODS: Custom in-house software was developed for objective quantification of cross-sectional stent area from computed tomography (CT) data. The technique was validated by in vitro experiments. The study included 39 patients (22 men; mean age, 59.2 y) who underwent TIPS creation (VIATORR stent graft [W. L. Gore & Associates, Flagstaff, Arizona]; n = 29; WALLSTENT endoprosthesis [Boston Scientific, Marlborough, Massachusetts], n = 10) with stent underdilation. Follow-up CT data of the patients were used to quantify in vivo stent area changes. Data were analyzed by variance analysis and entered into a general linear model to test for interrelations between stent area changes and clinical (eg, cirrhosis grade) and procedural parameters. RESULTS: In vitro validation of the in-house software showed good agreement and reproducibility without overestimation of stent area. Mean clinical follow-up time in patients was 787 days (range, 7-2,450 d). At the time of intervention, VIATORR stent grafts and WALLSTENT endoprostheses were dilated to an average of 64.4% ± 2.3% and 65.63% ± 8.52% of nominal area, respectively. At the last imaging follow-up evaluation, this value had increased in all stents to a mean of 87.8% ± 7.9% (VIATORR) and 82.34% ± 19.6% (WALLSTENT) in the TIPS tract (P < .05). Multivariate analysis revealed the time after intervention to be the only predictor of stent area in the TIPS tract. There was no significant association between stent expansion and clinical or procedure-related parameters. CONCLUSIONS: The area of self-expanding stents implanted in the liver for TIPS creation with dilation to less than nominal diameter significantly increases over time. This increase has to be considered as an additional factor influencing the long-term portosystemic gradient.