Purpose To investigate the value of T2-weighted-based radiomics compared with qualitative assessment at T2-weighted imaging and diffusion-weighted (DW) imaging for diagnosis of clinical complete response in patients with rectal cancer after neoadjuvant chemotherapy-radiation therapy (CRT). Materials and Methods This retrospective study included 114 patients with rectal cancer who underwent magnetic resonance (MR) imaging after CRT between March 2012 and February 2016. Median age among women (47 of 114, 41%) was 55.9 years (interquartile range, 45.4-66.7 years) and median age among men (67 of 114, 59%) was 55 years (interquartile range, 48-67 years). Surgical histopathologic analysis was the reference standard for pathologic complete response (pCR). For qualitative assessment, two radiologists reached a consensus. For radiomics, one radiologist segmented the volume of interest on high-spatial-resolution T2-weighted images. A random forest classifier was trained to separate the patients by their outcomes after balancing the number of patients in each response category by using the synthetic minority oversampling technique. Statistical analysis was performed by using the Wilcoxon rank-sum test, McNemar test, and Benjamini-Hochberg method. Results Twenty-one of 114 patients (18%) achieved pCR. The radiomic classifier demonstrated an area under the curve of 0.93 (95% confidence interval [CI]: 0.87, 0.96), sensitivity of 100% (95% CI: 0.84, 1), specificity of 91% (95% CI: 0.84, 0.96), positive predictive value of 72% (95% CI: 0.53, 0.87), and negative predictive value of 100% (95% CI: 0.96, 1). The diagnostic performance of radiomics was significantly higher than was qualitative assessment at T2-weighted imaging or DW imaging alone (P < .02). The specificity and positive predictive values were significantly higher in radiomics than were at combined T2-weighted and DW imaging (P < .0001). Conclusion T2-weighted-based radiomics showed better classification performance compared with qualitative assessment at T2-weighted and DW imaging for diagnosing pCR in patients with locally advanced rectal cancer after CRT. RSNA, 2018 Online supplemental material is available for this article.

 The rapid guide includes three diagnosis recommendations and four management recommendations covering patients with suspected or confirmed COVID-19 with different levels of disease severity, throughout the care pathway from outpatient facility or hospital entry, to home discharge.  The rapid guide offers considerations about implementation, monitoring and evaluation, and identifies research needs.  The guide will be relevant for clinicians, hospital managers and planners, policy-makers, hospital architects, biomedical engineers, medical physicists, logistics staff, and control officers involved in water/sanitation and infection prevention.

Imaging has become key in the care pathway of communicable and non-communicable diseases. Yet, there are major shortages of imaging equipment and workforce in low-and middle-income countries (LMICs). The International Society of Radiology outlines a plan to upscale the role of imaging in the global health agenda and proposes a holistic approach for LMICs. A generic model for organising imaging services in LMICs via regional Centres of Reference is presented. The need to better exploit IT and the potential of artificial intelligence for imaging, also in the LMIC setting, is highlighted. To implement the proposed plan, involvement of professional and international organisations is considered crucial. The establishment of an International Commission on Medical Imaging under the umbrella of international organisations is suggested and collaboration with other diagnostic disciplines is encouraged to raise awareness of the importance to upscale diagnostics at large and to foster its integration into the care pathway globally.

Purpose To determine the impact of three different methods of region of interest (ROI) positioning for apparent diffusion coefficient (ADC) measurements on the assessment of complete response (CR) to neoadjuvant combined chemotherapy and radiation therapy (CRT) in patients with rectal cancer. Materials and Methods Institutional review board approval was obtained for this study; all patients gave written informed consent. ADCs were measured by two radiologists using three circular ROIs (three-ROIs), single-section (SS), and whole-tumor volume (WTV) methods in 62 patients with locally advanced rectal cancer on pre- and post-CRT images. Interobserver variability was analyzed by calculating intraclass correlation coefficient (ICC). Descriptive statistics and areas under the receiver operating characteristic curves (AUCs) were calculated to evaluate performance in determining CR from pre- and post-CRT ADCs and ADC change. Histopathologic tumor regression grade was the reference standard. Results SS and WTV methods yielded higher AUCs than did the three-ROIs method when determining CR from post-CRT ADC (0.874 [95% confidence interval {CI}: 0.778, 0.970] and 0.886 [95% CI: 0.781, 0.990] vs 0.731 [95% CI: 0.583, 0.878], respectively; P = .033 and P = .003) and numeric change (0.892 [95% CI: 0.812, 0.972] and 0.897 [95% CI: 0.801, 0.994] vs 0.740 [95% CI: 0.591, 0.890], respectively; P = .048 and P = .0021). Respective accuracies of SS, WTV, and three-ROIs methods were 79% (49 of 62), 77% (48 of 62), and 61% (38 of 62) for post-CRT, 79% (49 of 62), 86% (53 of 62), and 60% (37 of 62) for numeric ADC change, and 77% (48 of 62), 84% (52 of 62), and 57% (35 of 62) for percentage ADC change (ADC cut-offs: 1.21, 1.30, and 1.05 × 10 mm/sec, 0.33, 0.45, and 0.27 × 10 mm/sec increases, and 40%, 54%, and 27% increases, respectively). Post-CRT and ADC change measurements achieved negative predictive values of 96% (44 of 46) to 100% (39 of 39). Intraobserver agreement was highest for WTV-derived ADCs (ICC, 0.742 [95% CI: 0.316, 0.892] to 0.891 [95% CI: 0.615, 0.956]) and higher for all pretreatment than posttreatment measurements (ICC, 0.761 [95% CI: 0.209, 0.930] and 0.648 [95% CI: 0.164, 0.895] for three-ROIs method, 0.608 [95% CI: 0.287, 0.844] and 0.582 [95% CI: 0.176, 0.870] for SS method, 0.891 [95% CI: 0.615, 0.956] and 0.742 for WTV method [95% CI: 0.316, 0.892]). Conclusion Tumor ADCs are highly dependent on the ROI positioning method used. Larger area measurements yield greater accuracy in response assessment. Post-CRT ADCs and values of ADC changes accurately identify noncomplete responders. WTV measurement of percentage ADC change provides the best results. RSNA, 2016 An earlier incorrect version of this article appeared online. This article was corrected on September 19, 2016.