Froemming, Adam T.

BackgroundUncertainty regarding the reproducibility of the apparent diffusion coefficient (ADC) hampers the use of quantitative diffusion‐weighted imaging (DWI) in evaluation of the prostate with magnetic resonance imaging MRI. The quantitative imaging biomarkers alliance (QIBA) profile for quantitative DWI claims a within‐subject coefficient of variation (wCV) for prostate lesion ADC of 0.17. Improved understanding of ADC reproducibility would aid the use of quantitative diffusion in prostate MRI evaluation.PurposeEvaluation of the repeatability (same‐day) and reproducibility (multi‐day) of whole‐prostate and focal‐lesion ADC assessment in a multi‐site setting.Study TypeProspective multi‐institutional.SubjectsTwenty‐nine males, ages 53 to 80 (median 63) years, following diagnosis of prostate cancer, 10 with focal lesions.Field Strength/Sequence3T, single‐shot spin‐echo diffusion‐weighted echo‐planar sequence with four b‐values.AssessmentSites qualified for the study using an ice‐water phantom with known ADC. Readers performed DWI analyses at visit 1 (“V1”) and visit 2 (“V2,” 2–14 days after V1), where V2 comprised scans before (“V2pre”) and after (“V2post”) a “coffee‐break” interval with subject removal and repositioning. A single reader segmented the whole prostate. Two readers separately placed region‐of‐interests for focal lesions.Statistical TestsReproducibility and repeatability coefficients for whole prostate and focal lesions derived from median pixel ADC. We estimated the wCV and 95% confidence interval using a variance stabilizing transformation and assessed interreader reliability of focal lesion ADC using the intraclass correlation coefficient (ICC).ResultsThe ADC biases from b0–b600 and b0–b800 phantom scans averaged 1.32% and 1.44%, respectively; mean b‐value dependence was 0.188%. Repeatability and reproducibility of whole prostate median pixel ADC both yielded wCVs of 0.033 (N = 29). In 10 subjects with an evaluable focal lesion, the individual reader wCVs were 0.148 and 0.074 (repeatability) and 0.137 and 0.078 (reproducibility). All time points demonstrated good to excellent interreader reliability for focal lesion ADC (ICCV1 = 0.89; ICCV2pre = 0.76; ICCV2post = 0.94).Data ConclusionThis study met the QIBA claim for prostate ADC. Test–retest repeatability and multi‐day reproducibility were largely equivalent. Interreader reliability for focal lesion ADC was high across time points.Level of Evidence1Technical EfficacyStage 2TOC CategoryPelvis

Background Due to their easy accessibility, CT scans have been increasingly used for investigation of gastrointestinal (GI) bleeding. Purpose To estimate the performance of a dual-phase, dual-energy (DE) GI bleed CT protocol in patients with overt GI bleeding in clinical practice and examine the added value of portal phase and DE images. Materials and Methods Consecutive patients with GI bleeding underwent a two-phase DE GI bleed CT protocol. Two gastroenterologists established the reference standard. Performance was estimated using clinical CT reports. Three GI radiologists rated confidence in GI bleeding in a subset of 62 examinations, evaluating first mixed kV arterial images, then after examining additional portal venous phase images, and finally after additional DE images (virtual non-contrast and virtual monoenergetic 50 keV images). Results 52 of 176 patients (29.5%) had GI bleeding by the reference standard. The overall sensitivity, specificity, and positive and negative predictive values of the CT GI bleed protocol for detecting GI bleeding were 65.4%, 89.5%, 72.3%, and 86.0%, respectively. In patients with GI bleeding, diagnostic confidence of readers increased after adding portal phase images to arterial phase images ( p = 0.002), without additional benefit from dual energy images. In patients without GI bleeding, confidence in luminal extravasation appropriately decreased after adding portal phase, and subsequently DE images ( p = 0.006, p = 0.018). Conclusion A two-phase DE GI bleed CT protocol had high specificity and negative predictive value in clinical practice. Portal venous phase images improved diagnostic confidence in comparison to arterial phase images alone. Dual-energy images further improved radiologist confidence in the absence of bleeding.

PurposeTo reduce slice‐to‐slice motion effects in multislice ‐weighted fast‐spin‐echo ( FSE) imaging, manifest as “scalloping” in reformats, by modification of the acquisition strategy and to show applicability in prostate MRI.Methods FSE images of contiguous or overlapping slices are typically acquired using multiple passes in which each pass is comprised of multiple slices with slice‐to‐slice gaps. Combination of slices from all passes provides the desired sampling. For enhancement of through‐plane resolution with super resolution or for reformatting into other orientations, subtle ≈1 mm motion between passes can cause objectionable “scalloping” artifact. Here we address this by subdivision of each pass into multiple segments. Interleaving of segments from the multiple passes causes all slices to be acquired over substantially the same time, reducing pass‐to‐pass motion effects. This was implemented in acquiring 78 overlapped FSE axial slices and studied in phantoms and in 14 prostate MRI patients. Super‐resolution axial images and sagittal reformats from the original and new segmented acquisitions were evaluated by 3 uroradiologists.ResultsFor all criteria of sagittal reformats, the segmented acquisition was statistically superior to the original. For all sharpness criteria of axial images, although the trend preferred the original acquisition, the difference was not significant. For artifact in axial images, the segmented acquisition was significantly superior.ConclusionsFor prostate MRI the new segmented acquisition significantly reduces the scalloping motion artifact that can be present in reformats due to long time lags between the acquisition of adjacent or overlapped slices while retaining image sharpness in the acquired axial slices.

PURPOSE Provide evidence- and expert-based recommendations for optimal use of imaging in advanced prostate cancer. Due to increases in research and utilization of novel imaging for advanced prostate cancer, this guideline is intended to outline techniques available and provide recommendations on appropriate use of imaging for specified patient subgroups. METHODS An Expert Panel was convened with members from ASCO and the Society of Abdominal Radiology, American College of Radiology, Society of Nuclear Medicine and Molecular Imaging, American Urological Association, American Society for Radiation Oncology, and Society of Urologic Oncology to conduct a systematic review of the literature and develop an evidence-based guideline on the optimal use of imaging for advanced prostate cancer. Representative index cases of various prostate cancer disease states are presented, including suspected high-risk disease, newly diagnosed treatment-naïve metastatic disease, suspected recurrent disease after local treatment, and progressive disease while undergoing systemic treatment. A systematic review of the literature from 2013 to August 2018 identified fully published English-language systematic reviews with or without meta-analyses, reports of rigorously conducted phase III randomized controlled trials that compared ≥ 2 imaging modalities, and noncomparative studies that reported on the efficacy of a single imaging modality. RESULTS A total of 35 studies met inclusion criteria and form the evidence base, including 17 systematic reviews with or without meta-analysis and 18 primary research articles. RECOMMENDATIONS One or more of these imaging modalities should be used for patients with advanced prostate cancer: conventional imaging (defined as computed tomography [CT], bone scan, and/or prostate magnetic resonance imaging [MRI]) and/or next-generation imaging (NGI), positron emission tomography [PET], PET/CT, PET/MRI, or whole-body MRI) according to the clinical scenario.

PurposeThe goal of this work is to demonstrate 1 mm through‐plane resolution in multislice T2SE MRI using k‐space processing of overlapping slices and show applicability in prostate MRI.MethodsMultiple overlapped slices are acquired and Fourier transformed in the slice‐select direction. The slice profile is incorporated into a Tikhonov‐regularized reconstruction. Through‐plane resolution is tested in a resolution phantom. An anthropomorphic prostate phantom is used to study the SNR, and results are compared with theoretical prediction. The proposed method is tested in 16 patients indicated for clinical prostate MRI who gave written informed consent as overseen by our IRB. The “proposed” vs. “reference” multislice images are compared using multiple evaluation criteria for through‐plane resolution.ResultsThe modulation transfer function (MTF) plots of the resolution phantom show good modulation at frequency 0.5 lp/mm, demonstrating 1 mm through‐plane resolution restoration. The SNR measurements experimentally match the theoretically predicted values. The radiological evaluation shows that the proposed method is superior to the reference method for five criteria of sharpness but inferior with respect to artifacts.ConclusionsIn conjunction with overlapped slices a k‐space‐based reconstruction approach can be used to improve through‐plane resolution in multislice T2SE MRI. 1 mm resolution is demonstrated from 3.2 mm thick slices. The in vivo results from prostate MRI show improved sharpness when compared to the standard multislice method.