Canadian Association of Radiologists Journal

Contrast-induced acute kidney injury or contrast-induced nephropathy (CIN) is a significant complication of intravascular contrast medium (CM). These guidelines are intended as a practical approach to risk stratification and prevention. The major risk factor that predicts CIN is pre-existing chronic kidney disease.

Members of the committee represent radiologists and nephrologists across Canada. The previous guidelines were reviewed, and an in-depth up-to-date literature review was carried out.

A serum creatinine level (SCr) should be obtained, and an estimated glomerular filtration rate (eGFR) should be calculated within 6 months in the outpatient who is stable and within 1 week for inpatients and patients who are not stable. Patients with an eGFR of ≥ 60 mL/min have an extremely low risk of CIN. The risk of CIN after intra-arterial CM administration appears be at least twice that after intravenous administration. Fluid volume loading remains the single most important measure, and hydration regimens that use sodium bicarbonate or normal saline solution should be considered for all patients with GFR < 60 mL/min who receive intra-arterial contrast and when GFR < 45 mL/min in patients who receive intravenous contrast. Patients are most at risk for CIN when eGFR < 30 mL/min. Additional preventative measures include the following: avoid dehydration, avoid CM when appropriate, minimize CM volume and frequency, avoid high osmolar CM, and discontinue nephrotoxic medications 48 hours before administration of CM.

To determine the cumulative effective dose (CED) of radiation from medical imaging and intervention in patients with hereditary hemorrhagic telangiectasia (HHT) who have pulmonary arteriovenous malformations and to identify clinical factors associated with exposure to high levels of radiation.

All patients with at least 1 pulmonary arteriovenous malformation were identified from the dedicated patient database of a tertiary HHT referral centre. Computerized imaging and electronic patient records were systematically examined to identify all imaging studies performed from 1989-2010. The effective dose was determined for each study, and CED was calculated retrospectively.

Among 246 patients (mean age, 53 years; 62.2% women) with a total of 2065 patient-years, 3309 procedures that involved ionizing radiation were performed. CED ranged from 0.2-307.6 mSv, with a mean of 51.7 mSv. CED exceeded 100 mSv in 26 patients (11%). Interventional procedures and computed tomography (CT) were the greatest contributors, which accounted for 51% and 46% of the total CED, respectively. Factors associated with high cumulative exposure were epistaxis (odds ratio 2.7 [95% confidence interval, 1.1-6.3]; P = .02), HHT-related gastrointestinal bleeding (odds ratio 2.0 [95% confidence interval, 1.0-3.8]; P = .04) and number of patient-years (P < .0001).

Patients with HHT are exposed to a significant cumulative radiation dose from diagnostic and therapeutic interventions. Identifiable subsets of patients are at increased risk. A proportion of patients receive doses at levels that are associated with harm. Imaging indications and doses should be optimized to reduce radiation exposure in this population.

This pictorial essay will review the magnetic resonance imaging anatomy of the temporal lobes and describe the major pathologic processes of this complex area.

Magnetic resonance imaging is an essential tool in the investigation of a patient with suspected temporal lobe pathology. Various conditions may affect this anatomic region, and, therefore, classification of imaging findings into specific groups may help provide a more focused differential diagnosis.

It has been suggested that assigned mentoring relationships are less successful than those that develop by free choice. This study evaluates radiology residents' overall experience with a mentoring program and compares the responses of those who self-selected mentors with those who were assigned mentors.

A voluntary Web-based survey was sent to 27 radiology residents in postgraduate years 3-5. Data collected included the following: year in residency, method of mentor assignment, duration of relationship, frequency and types of communication, perceived value of mentoring, overall satisfaction with the program, and the perceived impact of mentoring.

Twenty-five of 27 residents (93%) responded, with 14 having self-selected mentors (56%) and 11 having assigned mentors (44%). Both groups unanimously agreed that mentoring is beneficial or critical to their training; however, those residents with self-selected mentors were significantly more satisfied with the mentoring program (4 vs 3.3; P = .04) and more likely to consider their mentor as their primary mentor compared with those with assigned mentors (11 [79%] vs 4 [36%]; P = .049). Although all residents perceived a benefit, residents with self-selected mentors rated almost all mentoring parameters more positively than those with assigned mentors, although most of these parameters did not reach statistical significance.

Residents highly value the importance of mentoring. However, residents who self-select their mentors are more likely to be satisfied with a mentoring program.