Canadian Association of Radiologists Journal

The placement of localization clips following percutaneous biopsy is a standard practice for a variety of situations. Subsequent clip displacement creates challenges for imaging surveillance and surgical planning, and may cause confusion amongst radiologists and between surgeons and radiologists. Many causes have been attributed for this phenomenon including the commonly accepted “accordion effect.” Herein, we investigate the performance of a low cost surgical clip system against 4 commercially available clips.

We retrospectively reviewed 2112 patients who underwent stereotactic vacuum-assisted core biopsy followed by clip placement between January 2013 and June 2016. The primary performance parameter compared was displacement >10 mm following vacuum-assisted stereotactic core biopsy. Within the group of clips that had displaced, the magnitude of displacement was compared.

There was a significant difference in displacement among the clip types (P < .0001) with significant pairwise comparisons between pediatric surgical clips and SecureMark (38% vs 28%; P = .001) and SenoMark (38% vs 27%; P = .0001) in the proportion displaced. The surgical clips showed a significant magnitude of displacement of approximately 25% greater average distance displaced.

As a whole, the commercial clips performed better than the surgical clip after stereotactic vacuum-assisted core biopsy suggesting the surrounding outer component acts to anchor the central clip and minimizes clip displacement. The same should apply to tomosynthesis-guided biopsy.

The study sought to examine the association between clinical image quality of mammograms and screening sensitivity.

Four radiologists evaluated the clinical image quality of 374 invasive screen-detected cancers and 356 invasive interval breast cancers for which quality evaluation of screening mammograms could be assessed from cancers diagnosed among participants in the Quebec Breast Cancer Screening Program in 2007. Quality evaluation was based on the Canadian Association of Radiologists accreditation criteria, which are similar to those of the American College of Radiology. The association between clinical quality and screening sensitivity was assessed by logistic regression. Adjusted sensitivity and adjusted sensitivity ratios were obtained through marginal standardization. No institutional review board approval was required.

A proportion of 28% (206 of 730) of screening mammograms had lower overall quality for the majority of assessments. Positioning was the quality attribute that was the most frequently deficient. The 2-year screening sensitivity reached 68%. Sensitivity of screening was not statistically associated with the overall quality (ratio of 2-year sensitivity = 1.03; 95% confidence interval: 0.93-1.15) or with any quality attributes (positioning, exposure, compression, sharpness, artifacts, contrast). Results were similar for the 1-year sensitivity.

Although not all mammograms in the Quebec screening program met the optimum quality required by the Canadian Association of Radiologists or American College of Radiology accreditation, the screening mammograms produced in this population-based organized screening program reached a high enough level of quality so that the remaining variation in quality is too little to impair screening sensitivity.

Percutaneous radiofrequency ablation is so painful that this treatment requires pain control such as conscious sedation or general anesthesia. It is still unclear which type of anesthesia is better for treatment outcomes of renal cell carcinoma. This study aimed to compare general anesthesia and conscious sedation in treating patients with renal cell carcinoma with radiofrequency ablation.

Between 2010 and 2015, 51 patients with biopsy-proven renal cell carcinomas (<4 cm) were treated with computed tomography–guided radiofrequency ablation. General anesthesia was performed in 41 and conscious sedation was performed in 10 patients. Tumour size, local tumour progression, metastasis, major complication, effective dose, glomerular filtration rate difference, and recurrence-free survival rate were compared between these groups.

The mean tumour size was 2.1 cm in both groups (P = .673). Local tumour progression occurred in 0% (0 of 41) of the general anesthesia group, but in 40% (4 of 10) of the conscious sedation group (P = .001). Metastases in these groups occurred in 2.4% (1 of 41) of the general anesthesia group and 20% (2 of 10) of the conscious sedation group (P = .094). No major complications developed in either group after the first radiofrequency ablation session. The mean effective doses in these groups were 21.7 mSv and 21.2 mSv, respectively (P = .868). The mean glomerular filtration rate differences in the general anesthesia and conscious sedation groups were −13.5 mL/min/1.73 m² and −19.1 mL/min/1.73 m², respectively (P = .575). Three-year recurrence-free survival rates in these groups were 97.6% and 60.0%, respectively (P = .001).

General anesthesia may provide better intermediate outcomes than conscious sedation in treating small renal cell carcinomas with radiofrequency ablation.

To explore the patient perception on radiation-related cancer risk from interventional radiology (IR) procedures and whether informed radiation consent is warranted.

A multiple-choice survey was prospectively administered to 68 adults undergoing a body or neuro-IR procedure with ionizing radiation exposure. Subgroup analysis with chi-square or Fisher exact test was performed based on patient past IR history (P < .05).

A total of 81% of patients wanted to be informed if there was a radiation-related 3% increased cancer risk over 5 years. Although 55% considered 3% a small risk, 28% wanted to further discuss the risks and alternate options, and 15% would have only proceeded if it were a life-saving procedure: 89%, 80%, and 67% of patients wanted to be informed with exposure risks of 1 in 100, 1 in 1000, and 1 in 10,000, respectively. Only 53% were aware they were going to be exposed to radiation, irrespective of past IR history (P = .15). Most patients believed radiation consent should include radiation-related cancer risks (85%). No past IR history was significantly associated with wanting consent to include cancer-related risk (100% vs 76%; P = .01) and deterministic risks (70% vs 41%; P = .04). A majority (69%) believed both the referring physician and the interventional radiologist were responsible for obtaining radiation consent, and 65% of patients wanted verbal consent followed by signed written consent, regardless of past IR history.

Many patients want to discuss cancer-related radiation risks with both radiologists and physicians. Informed radiation consent should be considered for procedures with high anticipated radiation doses.

The study sought to determine the incidence of incidental findings on whole-body positron emission tomography with computed tomography (PET/CT) imaging and the average costs of investigations to follow-up or further characterize incidental findings.

Imaging reports of 215 patients who underwent whole-body PET/CT imaging were retrospectively reviewed. Our provincial picture archiving and communication system was queried and patient charts were reviewed to identify all investigations performed to follow-up incidental findings within 1 year of the initial PET/CT study. Costs of follow-up imaging studies (professional and technical components) and other diagnostic tests and procedures were determined in Canadian dollars (CAD) and U.S. dollars (USD) using the 2015 Ontario Health Insurance Plan Schedule of Benefits and Fees and 2016 U.S. Medicare Physician Fee Schedule, respectively.

At least 1 incidental finding was reported in 161 reports (74.9%). The mean number of incidental findings ranged from 0.64 in patients <45 years of age to 2.2 in patients 75 years of age and older. Seventy-five recommendations for additional investigations were made for 64 (30%) patients undergoing PET/CT imaging, and 14 of those were carried out specifically to follow-up incidental findings. Averaged across all 215 patients, the total cost of investigations recommended to follow-up incidental findings was CAD$105.51 (USD$127.56) per PET/CT study if all recommendations were acted on, and CAD$22.77 (USD$29.14) based on investigations actually performed.

As the incidence of incidental findings increases with age and a larger proportion of elderly patients is expected as population demographics change, it will be increasingly important to consider incidental findings on PET/CT imaging with standardized approaches to follow-up.

This retrospective study examined the performance of general radiologists in a community-based hospital in detecting colorectal cancer (CRC) with computed tomography (CT) in the unprepared large bowel.

The pathology database at a community hospital over the past 7 years (2009–2015) was retrospectively analysed for pathologically proven CRC (924 cases). The provincial hospital information profile for these patients was reviewed to determine if they had an abdominal CT for any reason in the year prior to biopsy. Metrics such as age, sex, time between the CT and biopsy or surgery, whether CRC was initially detected by the radiologist, and if this was an emergency presentation was evaluated. In the cases where CRC was not identified, the CT scans were reanalysed to determine if the CRC was identifiable in retrospect. The sensitivity of detecting CRC by CT scan in the unprepared large bowel was calculated.

Of the 924 biopsy proven CRC cases, 22% (207 of 924) of the patients had a CT prior to biopsy. Of these cases, 47% (97 of 207) presented on an emergency basis. Of the cases with imaging in the year prior, about 60% (125 of 207) had cancer prospectively detected by the radiologist. Upon re-examination of the cases in which CRC was not initially detected, 59% were visualized in retrospect.

Community general radiologists can successfully detect CRC with a high degree of accuracy. Reformatted images, bowel wall thickening when regional nodes are prominent, and minimizing oral contrast were helpful in improving detection.