Canadian Association of Radiologists Journal

The study sought to determine Canadian radiology resident perception of and interest in global health imaging (GHI) and the barriers they encounter in pursuing GHI experiences during residency training.

A peer-reviewed, online, anonymous, multiple-choice survey was distributed to Canadian radiology residents at English-language programs.

Fifty residents responded to the survey (∼16% response rate); 72% of respondents perceived an unmet need for medical imaging in the developing world. A majority of residents (60%) would have been likely to participate in a GHI experience if one had been available during their residency; 65% planned on pursuing international outreach work as future radiologists, 81% of whom with on-site collaboration in education and training of local staff. However, 82% of respondents were uncertain or believed they would not be adequately prepared to help improve access and availability of medical imaging services in developing countries upon completion of residency. Overall, residents believed a GHI program would increase their knowledge of infectious diseases, increase their exposure to diseases at advanced stage presentation, enhance their knowledge of basic imaging modalities, and improve their cultural competence. Lack of information about opportunities, lack of funding, and lack of infrastructure were ranked as the most important barriers to participating in a radiology rotation in a developing country during residency.

While many Canadian radiology residents are interested in participating in GHI, their preparation to do so may be inadequate. Formalizing international GHI rotations may alleviate barriers impeding their pursuit.

This study aimed to update our liver computed tomography (CT) protocol according to published guidelines, and to quantitatively evaluate the effect of these modifications.

The modified liver CT protocol employed a faster injection rate (5 vs 3 mL/s), later arterial phase (20-second vs 10-second postbolus trigger), and weight-based dosing of iodinated contrast (1.7 mL/kg vs 100 mL fixed dose). Liver and vascular attenuation values were measured on CTs of patients with cirrhosis from January to September 2015 (old protocol, n = 49) and from October to December 2015 (modified protocol, n = 31). CTs were considered adequate if liver enhancement exceeded 50 Hounsfield units (HU) in portal venous phase, or when the unenhanced phase was unavailable, if a minimum iodine concentration of 500 mg I/kg was achieved. Attenuations and iodine concentrations were compared using the t test and the number of suboptimal studies was compared with Fisher's exact test.

CTs acquired with the modified protocol demonstrated higher aortic (P = .001) and portal vein (P < .0001) attenuations in the arterial phase as well as greater hepatic attenuation on all postcontrast phases (P = .0006, .002, and .003 for arterial, venous, and equilibrium phases, respectively). Hepatic enhancement in the portal venous phase (61 ± 15 HU vs 51 ± 16 HU; P = .0282) and iodine concentrations (595 ± 88 mg I/kg vs 456 ± 112 mg I/kg; P < .0001) were improved, and the number of suboptimal studies was reduced from 57% to 23% (P = .01).

A liver CT protocol with later arterial phase, faster injection rate, and weight-based dosing of intravenous contrast significantly improves liver enhancement and iodine concentrations in patients with cirrhosis, resulting in significantly fewer suboptimal studies.

The study sought to prospectively evaluate which technique among T2-weighted images, dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI), diffusion-weighted (DW) MRI, or a combination of the 2, is best suited for prostate cancer detection and local staging.

Twenty-seven consecutive patients with biopsy-proven adenocarcinoma of the prostate underwent MRI on a 1.5T scanner with a surface phased-array coil prior radical prostatectomy. Combined anatomical and functional imaging was performed with the use of T2-weighted sequences, DCE MRI, and DW MRI. We compared the imaging results with whole mount histopathology.

For the multiparametric approach, significantly higher sensitivity values, that is, 53% (95% confidence interval [CI]: 41.0-64.1) were obtained as compared with each modality alone or any combination of the 3 modalities (P < .05). The specificity for this multiparametric approach, being 90.3% (95% CI: 86.3-93.3) was not significantly higher (P < .05) as compared with the values of the combination of T2+DCE MRI, DW+DCE MRI, or DCE MRI alone. Among the 3 techniques, DCE had the best performance for tumour detection in both the peripheral and the transition zone. High negative predictive value rates (>86%) were obtained for both tumour detection and local staging.

The combination of T2-weighted sequences, DCE MRI, and DW MRI yields higher diagnostic performance for tumour detection and local staging than can any of these techniques alone or even any combination of them.

Technological advancements and the ever-increasing use of computed tomography (CT) have greatly increased the detection of incidental findings, including tiny pulmonary nodules. The management of many “incidentalomas” is significantly influenced by a patient's history of cancer. The study aim is to determine if CT requisitions include prior history of malignancy.

Requisitions for chest CTs performed at our adult tertiary care hospital during April 2012 were compared to a cancer history questionnaire, administered to patients at the time of CT scan. Patients were excluded from the study if the patient questionnaire was incomplete or if the purpose of the CT was for cancer staging or cancer follow-up.

A total of 569 CTs of the chest were performed. Of the 327 patients that met inclusion criteria, 79 reported a history of cancer. After excluding patients for whom a history of malignancy could not be confirmed through a chart review and excluding nonmelanoma skin cancer, dysplasia, and in situ neoplasm, 68 patients were identified as having a history of malignancy. We found 44% (95% confidence interval [0.32-0.57]) of the chest CT requisitions for these 68 patients did not include the patient's history of cancer. Of the malignancies that were identified by patient questionnaire but omitted from the clinical history provided on the requisitions, 47% were malignancies that commonly metastasize to the lung.

A significant number of requisitions failed to disclose a history of cancer. Without knowledge of prior malignancy, radiologists cannot comply with current guidelines regarding the reporting and management of incidental findings.

The objective of the study was to evaluate the performance of magnetic resonance imaging (MRI) for the diagnosis of appendicitis during pregnancy.

We conducted a retrospective review of all MRI scans performed at our institution, between 2006 and 2012, for the evaluation of suspected appendicitis in pregnant women. Details of the MRI scans performed were obtained from the radiology information system as well as details of any ultrasounds carried out for the same indication. Clinical and pathological data were obtained by retrospective chart review.

The study population comprised 63 patients, and 8 patients underwent a second MRI scan during the same pregnancy. A total of 71 MRI scans were reviewed. The appendix was identified on 40 scans (56.3%). Sensitivity of MRI was 75% and specificity was 100% for the diagnosis of appendicitis in pregnant women. When cases with right lower quadrant inflammatory fat stranding or focal fluid, without appendix visualization, were classified as positive for appendicitis, MRI sensitivity increased to 81.3% but specificity decreased to 96.4%.

MRI is sensitive and highly specific for the diagnosis of appendicitis during pregnancy and should be considered as a first line imaging study for this clinical presentation.

The study sought to investigate the outcome of breast magnetic resonance–guided biopsies as a function of the indication for magnetic resonance imaging (MRI), the MRI features of the lesions, and the performance or not of a targeted second-look ultrasound (SLUS) prior breast MRI-guided biopsy.

We identified 158 women with MRI-detected breast lesions scheduled for MRI-guided biopsy (2007-2013). Patient demographics, performance of targeted SLUS, imaging characteristics, and subsequent pathology results were reviewed.

Three biopsies were deferred, and 155 lesions were biopsied under MRI guidance (155 women; median age 55.14 years; range 27-80 years). Ninety-eight women underwent a SLUS prior to the MRI-guided biopsy (63%). Of the 155 biopsied lesions, 23 (15%) were malignant, 106 (68%) were benign, and 26 (17%) were high risk. Four of 15 surgically excised high-risk lesions were upgraded to malignancy (27%). Most of the biopsied lesions corresponded to non–mass-like enhancement (81%, 126 of 155) and most of the biopsies (52%, 81 of 155) were performed in a screening context. No demographic or MRI features were associated with malignancy. No differences were noted between the 2 subgroups (prior SLUS vs no prior SLUS) except for the presence of a synchronous carcinoma associated with a likelihood of targeted SLUS before MRI-guided biopsy (P = .001).

A negative SLUS does not influence the pathology outcome of a suspicious lesion biopsied under MR guidance.

Vascular compression of the anterior optic pathway has been documented as an infrequent cause of visual impairments. Here we characterize such vascular compression using magnetic resonance imaging.

A total of 183 patients without pathologies affecting the optic pathways underwent T2-weighted or constructive interference steady-state sequence magnetic resonance imaging. Imaging data from coronal sections were analyzed.

A vascular compression of the anterior optic pathway was identified in 20 patients (11%). They comprised 13 men and 7 women with a mean age of 60.8 years. The vascular compressions were observed at 22 sites, 15 on the optic nerve (ON) and 7 on the optic chiasm (OC). Twelve of them were on the right and 10 were on the left side. The offending vessels were the supraclinoid portion of the internal carotid artery in 86.4% and the A1 segment of the anterior cerebral artery in 13.6%. Compression sites at the ON and OC were variable, with the inferolateral surface being the most frequent (77.3% occurrences). In 2 patients (9.1%), the ON was compressed in a sandwich manner.

Vascular compression of the ON and OC may not be an infrequent occurrence in the cranial cavity. Progressive and unexplainable visual impairment might possibly be caused by vascular-compressive neuropathy.

In the management of thyroid nodules, although the potential for malignancy exists, there is also the potential for overtreatment of subclinical disease. Although the TI-RADS (Thyroid Imaging-Reporting and Data System) system outlines a risk stratification score based on suspicious ultrasound findings, it has not been universally accepted. Many TI-RADS 2 or 3 patients proceed to fine needle aspiration biopsy (FNAB), potentially unnecessarily. The aim of the study was to identify whether lesions within a multinodular goiter (MNG) without suspicious features can be followed with ultrasound rather than biopsied as is recommended for single nodules.

Pathology records were retrospectively analysed for proven MNGs over a 5-year period. A total of 293 cases were identified. FNAB, prebiopsy ultrasound images, and reports were identified for each case. Images were reviewed and assessed for sonographically suspicious criteria guided by TI-RADS. Logistic regression was applied to determine if any sonographic features were associated with neoplasia. Odds ratios with 95% confidence intervals were calculated.

Of 293 samples, 14 (4.7%) were neoplastic. Having no suspicious features conferred an average risk of 0.0339 (95% confidence interval: 0.02831-0.04087) of neoplasia. Risk of neoplasm significantly increased by having 1 and >1 suspicious feature (P < .001). Regarding cytological results, of 237 patients with Thy-2 cytology, 159 were followed up and 8 had a neoplasm.

Ultrasound can be used to estimate risk of neoplasia in MNG. In the absence of suspicious radiological findings, follow-up with ultrasound rather than FNAB may be appropriate in patients who have a low clinical suspicion for neoplasia.

The study sought to investigate the presence of magnetic resonance (MR) signal alterations within the pericruciate fat pad in patients with an acute anterior cruciate ligament (ACL) tear as well as evaluate its diagnostic value in comparison with the main secondary signs of ACL tears.

Two musculoskeletal radiologists retrospectively reviewed knee MR examinations performed from May to October 2015. The ACL was considered as torn or intact based on either previous arthroscopic findings or unequivocal MR imaging interpretation if arthroscopic correlation was unavailable. Abnormalities of the pericruciate fat pad were evaluated as increased signal on the fluid-sensitive sequences; the main secondary signs of ACL tears were identified. Sensitivity and specificity were calculated for each sign.

A total of 182 patients entered this study: 22 with an acute ACL tear, 160 with intact ACL. Signal hyperintensity of the pericruciate fat pad was demonstrated in all patients with an acutely torn ACL, resulting significantly different between individuals with intact ACL and those with ligament tear (P < .0001). This sign was much more sensitive (100%) but less specific (72.5%-75%) than other secondary signs.

Signal hyperintensity of the pericruciate fat pad on the fluid-sensitive sequences is associated with acute ACL tears and could be considered as a possible indicator of these injuries.

Radioactive seed localization (RSL) uses a titanium seed labeled with iodine-125 energy for surgery of nonpalpable breast lesions. RSL facilitates radiology–surgery scheduling and allows for improved oncoplasty compared with wire localization (WL). The purpose of this work was to compare the 2 techniques.

We performed a retrospective study of all breast lesions operated with RSL between February 2013 and March 2015 at our university institution, and compared with an equivalent number of surgeries performed with a single WL. Imaging and pathology reports were reviewed for information on guidance mode, accuracy of targeting, nature of excised lesion, size and volume of surgical specimen, status of margins, and reinterventions.

A total of 254 lesions (247 women) were excised with RSL and compared with 257 lesions (244 women) whose surgery was guided by WL. Both groups were comparable in lesion pathology, guidance mode for RSL or WL positioning, and accuracy of targeting (98% correct). Mean delay between biopsy and surgery was 84 days for RSL versus 103 after WL (P = .04). No differences were noted after RSL or WL for surgical specimen mean weight, largest diameter, and volume excised. For malignancies, the rate of positive margins was comparable (2.8%-3%), with 5 of 10 women in the RSL group who underwent a second surgery displaying residual malignancy compared with 3 of 9 women in the WL group.

RSL is safe and accurate, and has comparable surgical endpoints to WL. Because RSL offers flexible scheduling and facilitated oncoplasty, RSL may replace WL for resection of nonpalpable single breast lesions.