Canadian Association of Radiologists Journal

To establish local diagnostic reference levels (DRL) for typical radiographic examinations in a fully digital imaging institution.

The initial survey included 6 standard radiographic projections performed in 19 computed radiography (CR) and digital radiography (DR) rooms. Because of the expected difference in the performance, the local reference levels were analysed separately for those 2 modalities. Data of 226 average size adult patients were included in the analysis. Entrance surface dose (ESD) was calculated from the recorded radiographic techniques and tube radiation output measurements. After observing wide variations in the results of the patient survey, the examinations were repeated by using anthropomorphic phantoms. Initial efforts to understand the reasons for dose variations were focused on CR chest, abdomen, pelvis, and lumbar spine examinations.

The average size patient doses for similar examinations were lower in the DR rooms than in the CR rooms by factors that ranged from 1.2 to 3, with the exception of the chest examination. Standardization of the CR exposure index value allowed us to decrease ESD by 21%-30%. Detector sensitivity had an insignificant effect (2%) on ESD; proper collimation lowered the dose by 17%. However, the major effect, up to 46% difference, was found because of antiscatter grids cutoff.

Modality specific local diagnostic reference levels for standard examinations have been established in a large digital imaging department with hybrid modalities. Typically the local reference values were lower than those recommended in Safety Code 35, except for CR chests. Factors that affect the dose variations have been investigated and determined.

To determine the relationship of increasing body mass index (BMI) and abdominal fat on the effective dose acquired from computed tomography (CT) abdomen and pelvis scans.

Over 6 months, dose-length product and total milliamp-seconds (mAs) from routine CT abdomen and pelvis scans of 100 patients were recorded. The scans were performed on a 64-slice CT scanner by using an automatic exposure control system. Effective dose (mSv) based on dose-length product, BMI, periumbilical fat thickness, and intra-abdominal fat were documented for each patient. BMI, periumbilical fat thickness, and intra-abdominal fat were compared with effective dose.

Thirty-nine men and 61 women were included in the study (mean age, 56.3 years). The mean BMI was 26.2 kg/m². The mean effective dose was 10.3 mSv. The mean periumbilical fat thickness was 2.4 cm. Sixty-five patients had a small amount of intra-abdominal fat, and 35 had a large amount of intra-abdominal fat. The effective dose increased with increasing BMI (P < .001) and increasing amounts of intra-abdominal fat (P < .001). For every kilogram of weight, there is a 0.13 mSv increase in effective dose, which is equal to 6.5 chest radiographs per CT examination. For an increase in BMI by 5 kg/m², there is a 1.95 mSv increase in effective dose, which is equal to 97.5 chest radiographs per CT examination.

Increasing BMI and abdominal fat significantly increases the effective dose received from CT abdomen and pelvis scans.

Results of previous studies have shown that repeated abdominopelvic computed tomography (CT) examinations can lead to substantial cumulative diagnostic radiation exposure in patients with Crohn's disease (CD). Improved selection of patients referred for CT will reduce unnecessary radiation exposure. This study examines if serum C-reactive protein (CRP) concentration predicts which symptomatic patients with CD are likely to have significant disease activity or disease complications (such as abscess) detected on abdominopelvic CT.

All abdominopelvic CTs performed on patients with CD at a tertiary referral centre during the period June 2003 to June 2008 were identified. CT findings were coded by a pair of independent blinded senior radiologists for (i) small bowel luminal disease, (ii) large bowel luminal disease, (iii) mesenteric inflammatory changes, (iv) penetrating disease (fistulas, abscess, or phlegmon), (v) acute disease complications (obstruction or perforation), and (vi) acute non-CD findings. Imaging findings were correlated with serum CRP checked within 14 days before imaging. The reference range for CRP was defined as 0–5 mg/L.

A total of 147 patients with symptomatic CD had a CRP assay performed within 14 days before undergoing abdominopelvic CT. The median time from CRP assay to imaging was 2 days (interquartile range, 0-6 days). Median CRP before imaging was 24 mg/L (interquartile range, 6-88 mg/L). CT was normal in 34 of 147 case (23.1%). Patients with normal CRP (n = 36) were significantly less likely to have penetrating disease (odds ratio [OR], 0.04 [95% confidence interval {CI}, 0.01-0.7]; P < .001) or large bowel luminal disease (OR, 0.3 [95% CI, 0.1-0.8]; P < .05). Normal CRP excluded penetrating disease with a sensitivity of 1.0 (95% CI, 0.87-1.0). CRP levels did not correlate with the presence of small bowel luminal disease (n = 82), mesenteric inflammatory changes (n = 68), or acute disease complications (n = 10).

Symptomatic patients with CD and normal serum CRP are unlikely to have evidence of abscess, fistulating disease, or large bowel luminal disease detected on abdominopelvic CT. However, abdominopelvic CT may demonstrate evidence of clinically significant non-penetrating CD or complications, including perforation and acute obstruction, regardless of serum CRP concentration.

To determine the incidence of fluorine-18-fluorodeoxyglucose (FDG) avid thyroid incidentalomas detected on positron emission tomography (PET) with integrated computed tomography (CT), and correlate the FDG–PET-CT findings to cytology.

A total of 942 FDG–PET-CT reports were retrospectively reviewed. Patients with FDG-avid thyroid incidentalomas were further reviewed for correlative cytology.

The incidence of FDG-avid thyroid incidentalomas is 2.2%. Thyroid malignancies were identified in 3 of 6 patients who underwent cytologic correlation, with a positive predictive value of 50% (95% confidence interval, 14%-86%). The mean maximum standardized uptake values of benign and malignant FDG-avid thyroid incidentalomas were 5.6 and 6.6, respectively.

A FDG-avid thyroid incidentaloma may predict underlying malignancy. Cytologic assessment should be considered for FDG-avid thyroid incidentalomas.

Findings not associated with thromboembolic disease on routine perfusion lung scan may sometimes have particular clinical significance. We wanted to assess the clinical importance and overall survival after the recognition of a lymphangitic carcinomatosis pattern on perfusion lung scan.

We report a case of lymphangitic carcinomatosis pattern on perfusion lung scan performed in a previously healthy patient who had rapid progressive course and died the next day.

A Medline search of case reports that describes either lymphangitic carcinomatosis or tumour microemboli on perfusion lung scan.

There were a total of 32 patients identified in 21 articles from various countries, including our case. The studied perfusion pattern was reported more often in female patients (81%) was associated with a progressive history of dyspnea (69%) and normal or mild findings on chest radiograph (58%). Of the 29 patients with available outcome data, 79% (23/29) had a progressive course after the lung scan interpretation. In 18 of these 23 cases, the actual interval of survival was given: 67% of these patients (12/18) died within the first month.

A lymphangitic carcinomatosis perfusion pattern on scintigraphic imaging is associated with a poor prognosis. Nuclear medicine physicians should be aware of this association and that raising the suspicion for a metastatic process may make a difference in the treatment plan of these patients.

To investigate the performance of different b values and regions of interest (ROI) for diagnosing liver fibrosis in patients with chronic viral hepatitis by using diffusion-weighted (DW) magnetic resonance imaging (MRI).

Eleven healthy participants and 33 patients with viral hepatitis B or C were enrolled. The stage of liver fibrosis and the grade of necroinflammation were determined by using a histologic activity index. Single-shot spin-echo echo-planar DW-MRI was performed in all participants at b values of 0-500, 0-700, and 0-1000 s/mm² by using 2 circular small and large ROIs of 100 and 200 mm². To evaluate the performance of different b values for determining cirrhosis, the receiver-operating characteristic curves were depicted, and the areas under the curves were compared.

The average values of apparent diffusion coefficients significantly decreased with increasing stage or grade categories at all the 3 b values and for both small and large ROIs. The performance at b = 500 s/mm² was significantly better than b = 1000 s/mm² for determining cirrhosis or bridging fibrosis. The cut point of 153.4 for apparent diffusion coefficient (×10⁻⁵ mm²/s) at b = 500 s/mm² could determine cirrhosis or bridging fibrosis with a sensitivity of 96% and specificity of 82%. No difference was found between the average apparent diffusion coefficient values of large or small ROIs. Also, there was no difference in performance of large or small ROIs in the diagnosis of liver fibrosis.

This study provided beneficial data for clinical utilisation of DW-MRI in diagnosing liver fibrosis: b = 500 s/mm² is better in performance than b = 1000 s/mm², and a small ROI of 100 mm² is sufficient for determining cirrhosis or bridging fibrosis.

Pneumatosis intestinalis is a radiologic diagnosis that manifests in a variety of clinical settings. We report 4 cases of pneumatosis intestinalis in patients undergoing cancer treatments that included cytotoxic agents and/or tyrosine kinase inhibitors. These reports aim to provide insight into the clinical interpretation and pathogenesis of pneumatosis intestinalis in the setting of cancer treatments and demonstrate a potential association with tyrosine kinase inhibitors.

Radiologists responsible for the interpretation of adult imaging at our tertiary care centre were surveyed to identify cases of pneumatosis intestinalis arising in the midst of cancer treatment. The case histories were reviewed by physicians with expertise in cancer treatment.

Four cases of chemotherapy-related pneumatosis intestinalis were identified. The diagnosis was made in 1 patient during investigations undertaken for non–life-threatening abdominal symptoms and incidentally in 2 patients by abdominal imaging used to measure chemotherapy response. A fourth patient presented in a life-threatening manner, and abdominal imaging was symptom guided. Interestingly, 3 of the 4 patients were receiving treatments that included a tyrosine kinase inhibitor, and this agent was the only identifiable potential etiology in 1 patient.

The significance of pneumatosis intestinalis arising during cancer treatments is difficult to interpret because of the complex nature of the diseases and the treatments that often include combinations of cytotoxic agents and/or novel therapies. These reports demonstrate the importance of classifying this radiologic finding according clinical severity rather than etiology and underscore the need for continued observation for unexplained adverse effects when using novel therapies.

To compare the complications experienced for 2 different brands of peripherally inserted central venous catheters (PICC), Cook Turbo-Ject and the Bard PowerPICC Solo2. The rationale for this project revolved around concern that one of the PICCS in question had high rates of complications.

A prospective clinical trial was conducted after obtaining approval from the University of Saskatchewan Human Research Ethics Committee. All PICCs were implanted at the Royal University Hospital Medical Imaging Department by an interventional radiologist. Patient randomization was achieved by alternating the brand of PICC implanted in sequential patients. All the subjects were inpatients from a single surgical ward. Patients were excluded from the study if they had a known uncorrected coagulopathy, or if they were being treated for venous thrombosis. This project was financially supported by the Summer Student Research Fund, College of Medicine, University of Saskatchewan.

A total of 53 PICCs (25 Bard and 28 Cook) were inserted over the study period. The mean PICC dwell time was 23.3 days for both the Bard and Cook PICCs, respectively. No statistically significant differences were detected in study group demographics, technical placement of the PICCs, or in the complications encountered.

Both the Cook Turbo-Ject and the Bard PowerPicc Solo2 PICCs provided acceptable venous access for a wide variety of clinical indications.