Canadian Association of Radiologists Journal-Journal De L Association Canadienne Des Radiologistes最新文献

The Canadian Association of Radiologists (CAR) metabolic dysfunction-associated steatotic liver disease (MASLD) Working Group (WG) is a multidisciplinary working group composed of radiologists, hepatologists, and family physicians. In this 3-part series, we provide Delphi consensus-based guidance on clinical and imaging findings for patients with known or suspected MASLD (formerly termed nonalcoholic fatty liver disease or NAFLD). Part 1 focuses on the detection and grading of hepatic steatosis on imaging; Part 2 on risk-stratification of patients with MASLD, including a patient pathway using serological and imaging investigations; and Part 3 on the implementation of practice recommendations for quality assurance using shear wave elastography (SWE) and magnetic resonance elastography (MRE) programs. In Part 2 of these guidelines, the WG provides 14 recommendations for risk stratifying MASLD patients into low and high risk for advanced hepatic fibrosis (F ≥ 3) using a combination of serological and imaging investigations. Population screening and risk stratification of MASLD patients using a clinical and serological investigation (FIB-4) followed by imaging pathway is recommended. Clinical, technical, and grading recommendations for point shear wave elastography (pSWE), 2-dimensional SWE (2D-SWE), and MRE are discussed.

Waiting times for medical imaging examinations in Canada are growing as the demand for these tests exceeds current capacity. This document summarizes strategies that may be employed to increase medical imaging patient throughput in an environment of limited resources. This document also advocates for provincial measures to optimize use of resources and national policies that support sustainable radiology services to meet growing demand now and in the future.

Purpose: In pelvic MRI, Turbo Spin Echo (TSE) pulse sequences are used for T2-weighted imaging. However, its lengthy acquisition time increases the potential for artifacts. Deep learning (DL) reconstruction achieves reduced scan times without the degradation in image quality associated with other accelerated techniques. Unfortunately, a comprehensive assessment of DL-reconstruction in pelvic MRI has not been performed. The objective of this prospective study was to compare the performance of DL-TSE and conventional TSE pulse sequences in a broad spectrum of pelvic MRI indications.

Methods: Fifty-five subjects (33 females and 22 males) were scanned at 3 T using DL-TSE and conventional TSE sequences in axial and/or oblique acquisition planes. Two radiologists independently assessed image quality in 6 categories: edge definition, vessel margin sharpness, T2 Contrast Dynamic Range, artifacts, overall image quality, and lesion features. The contrast ratio was calculated for quantitative assessment. A two-tailed sign test was used for assessment.

Results: The 2 readers found DL-TSE to deliver equal or superior image quality than conventional TSE in most cases. There were only 3 instances out of 24 where conventional TSE was scored as providing better image quality. Readers agreed on DL-TSE superiority/inferiority/equivalence in 67% of categories in the axial plane and 75% in the oblique plane. DL-TSE also demonstrated a better contrast ratio in 75% of cases. DL-TSE reduced scan time by approximately 50%.

Conclusion: DL-accelerated TSE sequences generally provide equal or better image quality in pelvic MRI than standard TSE with significantly reduced acquisition times.

Purpose: The precentral cortex normally demonstrates lower signal intensity compared to remainder of the neocortex on 2D fluid attenuated inversion recovery (FLAIR) images. Loss of this normal hypointensity bilaterally can be seen in patients with adult hypoxic-ischemic brain injury (HIBI). We have named this the 'FLAIR motor' sign (FMS). The performance of this sign for detection of HIBI is evaluated in this case-control study.

Methods: MRI studies of 74 consecutive patients with clinical evidence of HIBI following cardiac arrest formed the 'case' group. Controls comprised of normal MRI studies of an equal number of age and gender matched patients. Two fellowship-trained neuro-radiologists reviewed the MRI studies in a blinded randomized fashion and recorded the presence or absence of 'FLAIR motor' sign.

Results: Average time from cardiac arrest to MRI was 7.12 days (range: 1-25 days). The average sensitivity and specificity of 'FLAIR motor' sign for HIBI was 86.49% and 100% respectively. The sign demonstrated excellent inter-reader agreement (kappa >0.8).

Conclusion: The loss of the normal hypointensity in bilateral pre-central cortex on 2D-FLAIR images is a specific and reliable MRI sign of HIBI in the subacute phase following cardiac arrest in adults.