Faculty Bibliography

BACKGROUND/AIMS:Small intestinal bacterial overgrowth (SIBO) is a common condition in disorders of gut-brain interaction (DGBI). Recently, a combined scintigraphy-lactulose hydrogen breath test (ScLHBT) was described as an accurate tool diagnosing SIBO. We aim to analyze whether a lactulose nutrient challenge test (NCT), previously shown to separate DGBI from healthy volunteers, is equivalent to ScLHBT in diagnosing SIBO. METHODS:We studied data of 81 DGBI patients undergoing ScLHBT with 30 g lactulose and 300 mL water as well as NCT with 30 g lactulose and a 400 mL liquid test meal. Differences in proportion of positive SIBO diagnoses according to specified cecal load and time criteria for NCT and ScLHBT, respectively, were tested in an equivalence trial. An odds ratio (OR) range of 0.80-1.25 was considered equivalent. RESULTS:Diagnosis of SIBO during NCT was not equivalent to SIBO diagnosis in ScLHBT, considering a hydrogen increase before cecal load of 5.0%, 7.5%, or 10.0%, respectively ([OR, 3.76; 90% CI, 1.99-7.09], [OR, 1.87; 90% CI, 1.06-3.27], and [OR, 1.11; 90% CI, 0.65- 1.89]). Considering only time to hydrogen increase as criterion, the odds of a positive SIBO diagnosis in the NCT (0.65) was lower than in ScLHBT (1.70) (OR, 0.38; 90% CI, 0.23-0.65). CONCLUSIONS:This study could not show an equivalence of NCT and ScLHBT in diagnosing SIBO. A possible explanation might be the different transit times owing to unequal testing substances. The effect of this deviation in relation to consecutive therapy regimens should be tested in further prospective studies.

PURPOSE/OBJECTIVE:Prostate-specific membrane antigen positron emission tomography (PSMA-PET) has shown promise for detecting nodal and distant prostate cancer (PCa) metastases. However, its performance for local tumor staging is not as well established. The purpose of this study was to review the diagnostic performance of PSMA-PET for determining seminal vesical invasion (SVI) and extraprostatic extension (EPE). METHODS:Pubmed and Embase databases were searched until January 12, 2020. Studies assessing accuracy of PSMA-PET in determining SVI and EPE were included. Study quality was evaluated with the revised Quality Assessment of Diagnostic Accuracy Studies-2 tool. Pooled sensitivity and specificity were calculated using hierarchical summary receiver operating characteristics modeling. Heterogeneity was explored using meta-regression analyses for anatomical imaging component (MRI vs CT) and by testing for a threshold effect. RESULTS:Twelve studies (615 patients) were included. Pooled sensitivity and specificity were 0.68 (95% CI 0.53-0.81) and 0.94 (95% CI 0.90-0.96) for SVI and 0.72 (95% CI 0.56-0.84) and 0.87 (95% CI 0.72-0.94) for EPE. Meta-regression analyses showed that for SVI, PET/MRI demonstrated greater sensitivity than PET/CT (0.87 [95% CI 0.75-0.98] vs 0.60 [95% CI 0.47-0.74]; p = 0.02 for joint model) while specificity was comparable (0.91 [95% CI 0.84-0.97] vs. 0.96 [95% CI 0.93-0.99]) but not for EPE (p = 0.08). A threshold effect was present for studies assessing EPE (correlation coefficient = 0.563 [95% CI, -0.234-0.908] between sensitivity and false-positive rate). CONCLUSION/CONCLUSIONS:PSMA-PET has moderate sensitivity and excellent specificity for assessing local tumor extent in patients with PCa. PET/MRI showed potential for greater sensitivity than PET/CT in assessing SVI.

OBJECTIVES/OBJECTIVE:To assess interreader agreement of manual prostate cancer lesion segmentation on multiparametric MR images (mpMRI). The secondary aim was to compare tumor volume estimates between MRI segmentation and transperineal template saturation core needle biopsy (TTSB). METHODS:We retrospectively reviewed patients who had undergone mpMRI of the prostate at our institution and who had received TTSB within 190 days of the examination. Seventy-eight cancer lesions with Gleason score of at least 3 + 4 = 7 were manually segmented in T2-weighted images by 3 radiologists and 1 medical student. Twenty lesions were also segmented in apparent diffusion coefficient (ADC) and dynamic contrast enhanced (DCE) series. First, 20 volumetric similarity scores were computed to quantify interreader agreement. Second, manually segmented cancer lesion volumes were compared with TTSB-derived estimates by Bland-Altman analysis and Wilcoxon testing. RESULTS:Interreader agreement across all readers was only moderate with mean T2 Dice score of 0.57 (95%CI 0.39-0.70), volumetric similarity coefficient of 0.74 (0.48-0.89), and Hausdorff distance of 5.23 mm (3.17-9.32 mm). Discrepancy of volume estimate between MRI and TTSB was increasing with tumor size. Discrepancy was significantly different between tumors with a Gleason score 3 + 4 vs. higher grade tumors (0.66 ml vs. 0.78 ml; p = 0.007). There were no significant differences between T2, ADC, and DCE segmentations. CONCLUSIONS:We found at best moderate interreader agreement of manual prostate cancer segmentation in mpMRI. Additionally, our study suggests a systematic discrepancy between the tumor volume estimate by MRI segmentation and TTSB core length, especially for large and high-grade tumors. KEY POINTS/CONCLUSIONS:• Manual prostate cancer segmentation in mpMRI shows moderate interreader agreement. • There are no significant differences between T2, ADC, and DCE segmentation agreements. • There is a systematic difference between volume estimates derived from biopsy and MRI.

BACKGROUND:F]FDG PET/CT. METHODS:in the corresponding tissue depot by simple linear regression. RESULTS: = 0.42, p = 0.009). CONCLUSION/CONCLUSIONS:F] FDG PET-based imaging for quantification of BAT activity. TRIAL REGISTRATION/BACKGROUND:ClinicalTrials.gov. NCT03189511 , registered on June 17, 2017, actual study start date was on May 31, 2017, retrospectively registered. NCT03269747 , registered on September 01, 2017.

PURPOSE/OBJECTIVE:F-FDG PET/MR for the TNM classification. METHOD/METHODS:F-FDG PET/MR for the TNM classification were evaluated. RESULTS:F-FDG PET/MRI without statistical significance (p = 0.3827). CONCLUSION/CONCLUSIONS:F-FDG-PET/MR in this setting is necessary to assess the true value of this modality.

The aim of this study was to test an interactive up-to-date meta-analysis (iu-ma) of studies on MRI in the management of men with suspected prostate cancer. Based on the findings of recently published systematic reviews and meta-analyses, two freely accessible dynamic meta-analyses (https://iu-ma.org) were designed using the programming language R in combination with the package "shiny." The first iu-ma compares the performance of the MRI-stratified pathway and the systematic transrectal ultrasound-guided biopsy pathway for the detection of clinically significant prostate cancer, while the second iu-ma focuses on the use of biparametric versus multiparametric MRI for the diagnosis of prostate cancer. Our iu-mas allow for the effortless addition of new studies and data, thereby enabling physicians to keep track of the most recent scientific developments without having to resort to classical static meta-analyses that may become outdated in a short period of time. Furthermore, the iu-mas enable in-depth subgroup analyses by a wide variety of selectable parameters. Such an analysis is not only tailored to the needs of the reader but is also far more comprehensive than a classical meta-analysis. In that respect, following multiple subgroup analyses, we found that even for various subgroups, detection rates of prostate cancer are not different between biparametric and multiparametric MRI. Secondly, we could confirm the favorable influence of MRI biopsy stratification for multiple clinical scenarios. For the future, we envisage the use of this technology in addressing further clinical questions of other organ systems.

OBJECTIVES:Non-Cartesian spiral magnetic resonance (MR) acquisition may enable higher scan speeds, as the spiral traverses the k-space more efficiently per given time than in Cartesian trajectories. Spiral MR imaging can be implemented in time-of-flight (TOF) MR angiography (MRA) sequences. In this study, we tested the performance of five 3-dimensional TOF MRA sequences for intracranial vessel imaging at 1.5 T with qualitative and quantitative image quality metrics based on in vitro and in vivo measurements. Specifically, 3 novel spiral TOF MRA sequences (spiral-TOFs) and a compressed sensing (CS) technology-accelerated TOF MRA sequence (CS 3.5) were compared with a conventional (criterion standard) parallel imaging-accelerated TOF MRA sequence (SENSE). MATERIALS AND METHODS:The SENSE sequence (5:08 minutes) was compared with the CS 3.5 sequence (3:06 minutes) and a spiral-TOF (spiral, 1:32 minutes), all with identical resolutions. In addition, 2 further isotropic spiral-TOFs (spiral 0.8, 2:12 minutes; spiral 0.6, 5:22 minutes) with higher resolution were compared with the SENSE. First, vessel tracking experiments were performed in vitro with a dedicated vascular phantom to determine possible differences in the depiction of cross-sectional areas of vessel segments. For the in vitro tests, an additional 3-dimensional proton density-weighted sequence was added for comparison reasons. Second, 3 readers blinded to sequence details assessed qualitative (16 features) and 2 readers assessed quantitative (contrast-to-noise ratio [CNR], contrast ratio [CR], vessel sharpness, and full width at half maximum edge criterion measurements) image quality based on images acquired from scanning 10 healthy volunteers with all 5 TOF sequences. Scores from quantitative image quality analysis were compared with Kruskal-Wallis, analysis of variance, or Welch's analysis of variance, followed by Dunnett's or Dunnett's T3 post hoc tests. Scores from qualitative image quality analysis were compared with exact binomial tests, and the level of interreader agreement was determined with Krippendorff's alpha. RESULTS:Concerning the in vitro tests, there were no significant differences between the 5 TOFs and the proton density-weighted sequence in measuring cross-sectional areas of vessel segments (P = 0.904). As for the in vivo tests, the CS 3.5 exhibited equal qualitative image quality as the SENSE, whereas the 3 spiral-TOFs outperformed the SENSE in several categories (P values from 0.002 to 0.031). Specifically, the spiral 0.8 and 0.6 sequences achieved significantly higher scores in 12 categories. Interreader agreement ranged from poor (alpha = -0.013, visualization of internal carotid artery segment C7) to substantial (alpha = 0.737, number of vessels visible, sagittal). As for the quantitative metrics, the CS 3.5 and all 3 spiral-TOFs presented with significantly worse CNR than the SENSE ([mean ± SD] SENSE 37.48 ± 7.13 vs CS 3.5 31.14 ± 5.97 vs spiral 19.77 ± 1.65 vs spiral 0.8 16.18 ± 2.14 vs spiral 0.6 10.37 ± 1.05). The CR values did not differ significantly between the SENSE and the other TOFs except for the spiral sequence that showed significantly improved CR (SENSE 0.53 ± 0.03 vs spiral 0.56 ± 0.03). As for vessel sharpness, the SENSE was outperformed by all spiral-TOFs (SENSE 0.37 ± 0.03 vs spiral 0.52 ± 0.07 vs spiral 0.8 0.53 ± 0.08 vs spiral 0.6 0.73 ± 0.09), whereas the CS 3.5 performed equally well (SENSE 0.37 ± 0.03 vs CS 3.5 0.37 ± 0.03). Full width at half maximum values did not differ significantly between any TOF. CONCLUSIONS:Spiral-TOFs may deliver high-quality intracranial vessel imaging thus matching the performance of conventional parallel imaging-accelerated TOFs (such as the SENSE). Specifically, imaging can be performed at unprecedented scan times as short as 1:32 minutes per sequence (70.12% scan time reduction compared with SENSE). Optionally, spiral imaging may also be used to increase spatial resolution while maintaining the scan time of a Cartesian-based acquisition schema. The CNR was decreased in spiral-TOF images.

OBJECTIVES/OBJECTIVE:To compare interreader agreement and diagnostic accuracy of LI-RADS v2018 categorization using quantitative versus qualitative MRI assessment of arterial phase hyperenhancement (APHE) and washout (WO) of focal liver lesions. METHODS:Sixty patients (19 female; mean age, 56 years) at risk for HCC with 71 liver lesions (28 HCCs, 43 benign) who underwent contrast-enhanced MRI were included in this retrospective study. Four blinded radiologists independently assigned a qualitative LI-RADS score per lesion. Two other radiologists placed ROIs within the lesion, adjacent liver parenchyma, and paraspinal musculature on pre- and post-contrast MR images. The percentage of arterial enhancement and the liver-to-lesion contrast ratio were calculated for quantification of APHE and WO. Using these quantitative parameters, a quantitative LI-RADS score was assigned. Interreader agreement and AUCs were calculated. RESULTS:Interreader agreement was similar for qualitative and quantitative LI-RADS (κ = 0.38 vs. 0.40-0.47) with a tendency towards improved agreement for quantitatively assessed APHE (κ = 0.65 vs. 0.81) and WO (κ = 0.53 vs. 0.78). Qualitative LI-RADS showed an AUC of 0.86, 0.94, 0.94, and 0.91 for readers 1, 2, 3, and 4, respectively. The quantitative LI-RADS score where APHE/WO/or both were replaced showed an AUC of 0.89/0.84/0.89, 0.95/0.92/0.92, 0.93/0.91/0.89, and 0.91/0.86/0.88 for readers 1, 2, 3, and 4, respectively. Sensitivity of LR-4/5 slightly increased, while specificity slightly decreased using quantitative APHE. CONCLUSION/CONCLUSIONS:Qualitative and quantitative LI-RADS showed similar performance. Quantitatively assessed APHE showed the potential to increase interreader agreement and sensitivity of HCC diagnosis, whereas quantitatively assessed WO had the opposite effect and needs to be redefined. KEY POINTS/CONCLUSIONS:• Quantitative assessment of arterial phase hyperenhancement shows the potential to increase interreader agreement and sensitivity to diagnose hepatocellular carcinoma. • Adding quantitative measurements of major LI-RADS features does not improve accuracy over qualitative assessment alone according to the LI-RADS v2018 algorithm.

PURPOSE/OBJECTIVE:To evaluate a deep learning based image analysis software for the detection and localization of distal radius fractures. METHOD/METHODS:A deep learning system (DLS) was trained on 524 wrist radiographs (166 showing fractures). Performance was tested on internal (100 radiographs, 42 showing fractures) and external test sets (200 radiographs, 100 showing fractures). Single and combined views of the radiographs were shown to DLS and three readers. Readers were asked to indicate fracture location with regions of interest (ROI). The DLS yielded scores (range 0-1) and a heatmap. Detection performance was expressed as AUC, sensitivity and specificity at the optimal threshold and compared to radiologists' performance. Heatmaps were compared to radiologists' ROIs. RESULTS:The DLS showed excellent performance on the internal test set (AUC 0.93 (95% confidence interval (CI) 0.82-0.98) - 0.96 (0.87-1.00), sensitivity 0.81 (0.58-0.95) - 0.90 (0.70-0.99), specificity 0.86 (0.68-0.96) - 1.0 (0.88-1.0)). DLS performance decreased on the external test set (AUC 0.80 (0.71-0.88) - 0.89 (0.81-0.94), sensitivity 0.64 (0.49-0.77) - 0.92 (0.81-0.98), specificity 0.60 (0.45-0.74) - 0.90 (0.78-0.97)). Radiologists' performance was comparable on internal data (sensitivity 0.71 (0.48-0.89) - 0.95 (0.76-1.0), specificity 0.52 (0.32-0.71) - 0.97 (0.82-1.0)) and better on external data (sensitivity 0.88 (0.76-0.96) - 0.98 (0.89-1.0), specificities 0.66 (0.51-0.79) - 1.0 (0.93-1.0), p < 0.05). In over 90%, the areas of peak activation aligned with radiologists' annotations. CONCLUSIONS:The DLS was able to detect and localize wrist fractures with a performance comparable to radiologists, using only a small dataset for training.

OBJECTIVE. Industry relationships drive technologic innovation in interventional radiology and offer opportunities for professional growth. Women are underrepresented in interventional radiology despite the growing recognition of the importance of diversity. This study characterized gender disparities in financial relationships between industry and academic interventional radiologists. MATERIALS AND METHODS. In this retrospective cross-sectional study, U.S. academic interventional radiology physicians and their academic ranks were identified by searching websites of practices with accredited interventional radiology fellowship programs. Publicly available databases were queried to collect each physician's gender, years since medical school graduation, h-index, academic rank, and industry payments in 2018. Wilcoxon and chi-square tests compared payments between genders. A general linear model assessed the impact of academic rank, years since graduation, gender, and h-index on payments. RESULTS. Of 842 academic interventional radiology physicians, 108 (13%) were women. A total $14,206,599.41 was received by 686 doctors (81%); only $147,975.28 (1%) was received by women. A lower percentage of women (74%) than men (83%) received payments (p = 0.04); median total payments were lower for women ($535) than men ($792) (p = 0.01). Academic rank, h-index, years since graduation, and male gender were independent predictors of higher payments. Industry payments supporting technologic advancement were made exclusively to men. CONCLUSION. Female interventional radiology physicians received fewer and lower industry payments, earning 1% of total payments despite constituting 13% of physicians. Gender independently predicted industry payments, regardless of h-index, academic rank, or years since graduation. Gender disparity in interventional radiology physician-industry relationships warrants further investigation and correction.