Canadian Association of Radiologists Journal

This study aimed to determine the volumes and types of magnetic resonance imaging exams being performed across Canada, common indications for the exams, and exam appropriateness using multiple evaluation tools.

Thirteen academic medical institutions across Canada participated. Data were obtained relating to a single common day, October 1, 2014. Patient demographics, type by anatomic region and indication for imaging were analysed. Each exam was assessed for appropriateness via the Canadian Association of Radiologists Referral Guidelines and the American College of Radiology Appropriateness Criteria. The Alberta and Saskatchewan spine screening forms and the Alberta knee screening form were also used where applicable. The proportion of exams that were unscorable, appropriate, and inappropriate was determined. Exam-level results were compared between the 2 main evaluation tools.

Data were obtained for 1087 relevant exams. There were 591 women and 460 men. 36 requisitions did not indicate the patient's sex. Brain exams were the most common, comprising 32.5% of the sample. Cancer was the most common indication. Overall, 87.0%–87.4% of the MR exams performed were appropriate; 6.6%–12.6% were inappropriate, based on the 2 main evaluation tools. Results differed by anatomic region; spine exams had the highest proportion, with nearly one-third of exams deemed inappropriate.

Variations by anatomic region indicate that focused exam request evaluation or screening methods could substantially reduce inappropriate imaging.

Not all endoscopically placed clips (endoclips) are magnetic resonance imaging (MRI) compatible. At many institutions, endoclip screening is part of the pre-MRI screening process. Our objective is to determine the contribution of each step of this endoclip screening protocol in determining a patient's endoclip status at our institution.

A retrospective review of patients' endoscopic histories on general MRI screening forms for patients scanned during a 40-day period was performed to assess the percentage of patients that require endoclip screening at our institution. Following this, a prospective evaluation of 614 patients' endoclip screening determined the percentage of these patients ultimately exposed to each step in the protocol (exposure), and the percentage of patients whose endoclip status was determined with reasonable certainty by each step (determination).

Exposure and determination values for each step were calculated as follows (exposure, determination): verbal interview (100%, 86%), review of past available imaging (14%, 36%), review of endoscopy report (9%, 57%), and new abdominal radiograph (4%, 96%), or CT (0.2%, 100%) for evaluation of potential endoclips. Only 1 patient did not receive MRI because of screening (in situ gastrointestinal endoclip identified).

Verbal interview is invaluable to endoclip screening, clearing 86% of patients with minimal monetary and time investment. Conversely, the limited availability of endoscopy reports and relevant past imaging somewhat restricts the determination rates of these. New imaging (radiograph or computed tomography) is required <5% of the time, and although costly and associated with patient irradiation, has excellent determination rates (above 96%) when needed.

The study sought to determine if mammography quality is associated with the false positive (FP) rate in the Quebec breast cancer screening program in 2004 and 2005.

Mammography quality of a random sample of screen-film mammograms was evaluated by an expert radiologist following the criteria of the Canadian Association of Radiologists. For each screening examination, scores ranging from 1 (poor quality) to 5 (excellent quality) were attributed for positioning, compression, contrast, exposure level, sharpness, and artifacts. A final overall quality score (lower or higher) was also given. Poisson regression models with robust estimation of variance and adjusted for potential confounding factors were used to assess associations of mammography quality with the FP rate.

Among 1,209 women without cancer, there were 104 (8.6%) FPs. Lower overall mammography quality is associated with an increase in the FP rate (risk ratio [RR], 1.4; 95% confidence interval [CI], 1.0-2.1; P = .07) but this increase was not statistically significant. Artifacts were associated with an increase in the FP rate (RR, 2.1; 95% CI, 1.3-3.3; P = .01) whereas lower quality of exposure level was related to a reduction of the FP rate (RR, 0.4; 95% CI, 0.1-1.0; P = .01). Lower quality scores for all other quality attributes were related to a nonstatistically significant increase in the FP rate of 10%-30%.

Artifacts can have a substantial effect on the FP rate. The effect of overall mammography quality on the FP rate may also be substantial and needs to be clarified.

The percutaneous endovascular abdominal aortic repair (PEVAR) approach is a minimally invasive technique that has demonstrated clinical benefit over traditional surgical cut down associated with standard endovascular abdominal aortic aneurysm (AAA) repair (EVAR). The objective of our study was to evaluate the budget impact to a Canadian hospital of changing the technique for AAA repair from the EVAR approach to the PEVAR approach.

We examined the budget impact of replacing the EVAR approach with the PEVAR approach in a Canadian hospital that performs 100 endovascular AAA repairs annually. The model incorporates the costs associated with surgery, length of stay, and postoperative complications occurring within 30 days.

The use of PEVAR in AAA repair is associated with increased access device costs when compared with the EVAR approach (CAD$1000 vs CAD$400). However, AAA repair completed with the PEVAR approach demonstrates reduced operating time (101 minutes vs 133 minutes), length of stay (2.2 days vs 3.5 days), time in the recovery room (174 minutes vs 193 minutes), and postoperative complications (6% vs 30%), which offset the increased device costs. The model establishes that switching to the PEVAR approach in a Canadian hospital performing 100 AAA repairs annually would result in a potential cost avoidance of CAD$245,120.

A change in AAA repair technique from EVAR to PEVAR can be a cost-effective solution for Canadian hospitals.