Comparison of Abdominopelvic CT Diagnoses at Academic Teaching Hospitals in Rwanda and the United States

Purpose: The purpose of this study was to compare the disease processes encountered on abdominal and pelvic CT examinations at academic teaching hospitals in Rwanda and the United States and to highlight how these differences may impact a global radiology collaboration. Materials and Methods: In this retrospective study, we included 130 patients (mean 59 +/-17 years, range 20-91, F:M 74:56) who underwent abdominal/pelvic CT examinations between April 1st-12th, 2019. CT examinations were prospectively encountered in clinical work at the Centre Hospitalier Universitaire de Kigali or University Teaching Hospital of Kigali (CHUK) in Kigali, Rwanda, where the radiology report impression, patient age, gender, study indication, CT protocol, and clinical diagnosis were recorded when available. Abdominal/pelvic CT examinations at the Massachusetts General Hospital (MGH) in Boston, Massachusetts, United States were then retrospectively reviewed for the same information. Patient age and gender were compared using Student’s t-test and Chi-square statistic. Frequency of formal recommendations in radiology reports, available comparison of CT examinations, presence of known diagnoses, and intravenous and oral contrast media use were compared using Fisher’s exact test. Diagnostic categories were qualitatively compared. Results: A wide variety of pathology was encountered by abdominal/pelvic CT at both sites of imaging, with qualitative differences observed in cancer types, infectious agents, and how imaging guides care. Patients in Rwanda were older (p=0.0017), more likely to receive intravenous (p \u3c 0.05) and positive oral contrast (p \u3c 0.05) media and less likely to receive a formal recommendation in their radiology report (p \u3c 0.05). Patients in the United States were more likely to have an available prior abdominal/pelvic CT (p \u3c 0.05), to present for follow-up of a known diagnosis (p \u3c 0.05), and to receive a formal recommendation in their radiology report (p \u3c 0.05). Conclusion: Participation in global radiology collaborations is beneficial for radiologists by broadening exposure to pathologies and practice different from their own institution and region

The Role of MR Enterography in Assessing Crohn’s Disease Activity and Treatment Response

MR enterography (MRE) has become the primary imaging modality in the assessment of Crohn’s disease (CD) in both children and adults at many institutions in the United States and worldwide, primarily due to its noninvasiveness, superior soft tissue contrast, and lack of ionizing radiation. MRE technique includes distention of the small bowel with oral contrast media with the acquisition of T2-weighted, balanced steady-state free precession, and multiphase T1-weighted fat suppressed gadolinium contrast-enhanced sequences. With the introduction of molecule-targeted biologic agents into the clinical setting for CD and their potential to reverse the inflammatory process, MRE is increasingly utilized to evaluate disease activity and response to therapy as an imaging complement to clinical indices or optical endoscopy. New and emerging MRE techniques, such as diffusion-weighted imaging (DWI), magnetization transfer, ultrasmall superparamagnetic iron oxide- (USPIO-) enhanced MRI, and PET-MR, offer the potential for an expanded role of MRI in detecting occult disease activity, evaluating early treatment response/resistance, and differentiating inflammatory from fibrotic strictures. Familiarity with MR enterography is essential for radiologists and gastroenterologists as the technique evolves and is further incorporated into the clinical management of CD

Quantitative peritumoral magnetic resonance imaging fingerprinting improves machine learning-based prediction of overall survival in colorectal cancer

Aim: To investigate magnetic resonance imaging (MRI)-based peritumoral texture features as prognostic indicators of survival in patients with colorectal liver metastasis (CRLM). Methods: From 2007–2015, forty-eight patients who underwent MRI within 3 months prior to initiating treatment for CRLM were identified. Clinicobiological prognostic variables were obtained from electronic medical records. Ninety-four metastatic hepatic lesions were identified on T1-weighted post-contrast images and volumetrically segmented. A total of 112 radiomic features (shape, first-order, texture) were derived from a 10 mm region surrounding each segmented tumor. A random forest model was applied, and performance was tested by receiver operating characteristic (ROC). Kaplan-Meier analysis was utilized to generate the survival curves. Results: Forty-eight patients (male:female = 23:25, age 55.3 years ± 18 years) were included in the study. The median lesion size was 25.73 mm (range 8.5–103.8 mm). Microsatellite instability was low in 40.4% (38/94) of tumors, with Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation detected in 68 out of 94 (72%) tumors. The mean survival was 35 months ± 21 months, and local disease progression was observed in 35.5% of patients. Univariate regression analysis identified 42 texture features [8 first order, 5 gray level dependence matrix (GLDM), 5 gray level run time length matrix (GLRLM), 5 gray level size zone matrix (GLSZM), 2 neighboring gray tone difference matrix (NGTDM), and 17 gray level co-occurrence matrix (GLCM)] independently associated with metastatic disease progression (P < 0.03). The random forest model achieved an area under the curve (AUC) of 0.88. Conclusions: MRI-based peritumoral heterogeneity features may serve as predictive biomarkers for metastatic disease progression and patient survival in CRLM

Zero-DeepSub: Zero-Shot Deep Subspace Reconstruction for Rapid Multiparametric Quantitative MRI Using 3D-QALAS

Purpose: To develop and evaluate methods for 1) reconstructing 3D-quantification using an interleaved Look-Locker acquisition sequence with T2 preparation pulse (3D-QALAS) time-series images using a low-rank subspace method, which enables accurate and rapid T1 and T2 mapping, and 2) improving the fidelity of subspace QALAS by combining scan-specific deep-learning-based reconstruction and subspace modeling. Methods: A low-rank subspace method for 3D-QALAS (i.e., subspace QALAS) and zero-shot deep-learning subspace method (i.e., Zero-DeepSub) were proposed for rapid and high fidelity T1 and T2 mapping and time-resolved imaging using 3D-QALAS. Using an ISMRM/NIST system phantom, the accuracy of the T1 and T2 maps estimated using the proposed methods was evaluated by comparing them with reference techniques. The reconstruction performance of the proposed subspace QALAS using Zero-DeepSub was evaluated in vivo and compared with conventional QALAS at high reduction factors of up to 9-fold. Results: Phantom experiments showed that subspace QALAS had good linearity with respect to the reference methods while reducing biases compared to conventional QALAS, especially for T2 maps. Moreover, in vivo results demonstrated that subspace QALAS had better g-factor maps and could reduce voxel blurring, noise, and artifacts compared to conventional QALAS and showed robust performance at up to 9-fold acceleration with Zero-DeepSub, which enabled whole-brain T1, T2, and PD mapping at 1 mm isotropic resolution within 2 min of scan time. Conclusion: The proposed subspace QALAS along with Zero-DeepSub enabled high fidelity and rapid whole-brain multiparametric quantification and time-resolved imaging.Comment: 17 figures, 3 table

The move beyond edutainment: have we learnt our lessons from the entertainment industry?

Serious games (SGs) have been used in the education of students and professionals for decades, but still have not reached their full potential, despite the large consensus they have gained recently. The entertainment game industry is a rapidly developing phenomenon, with a high market potential, enabled and enhanced by technological innovation. The question examined in this paper is: Did serious game designers learn from Entertainment Game (EG) designers in building a successful game? This paper presents three case study examples of games that have good learning outcomes to explore this question. This paper discusses the salient aspects and the differences between the examples and suggests how SGs could learn more from successful EGs