Canadian Association of Radiologists Journal

The objectives of this study were to utilise the XCT-2000 pQCT scanner to determine the mean values and the reproducibility of in vivo total, trabecular, and cortical volumetric bone measurements at distal and diaphyseal sites of the radius and the tibia, as well as calf muscle and subcutaneous fat areas, in healthy pre- and postmenopausal women.

Twenty-nine women (14 premenopausal and 15 postmenopausal) were recruited to participate in this study. Distal and diaphyseal sites of the radius (at 4% and 20% of the length of the radius) and tibia (at 4%, 38%, and 66% of the length of the tibia) were examined.

The root mean square coefficient of variation for measurements at the distal tibia gave the most favorable reproducibility values for total (1.5%) and trabecular (1.6%) density, whereas the diaphyseal tibia showed the most favorable reproducibility value for cortical density (0.3%). The root mean square coefficients of variation for measurements of muscle and fat cross-sectional areas at the calf were 0.6% and 0.7%, respectively. At the distal tibia, the mean values for total (P < .05) and trabecular (P < .01) density were significantly lower in postmenopausal women than in premenopausal women.

The data presented here indicate that XCT-2000 pQCT scans at the tibia provide highly reproducible measurements of total, cortical, and trabecular bone as well as muscle and fat cross-sectional areas. Furthermore, significant differences in volumetric bone measurements between healthy pre- and postmenopausal women were evident only at the distal tibia, suggesting that this site warrants further study.

To measure the growth rate of microcystic subtype serous adenomas of the pancreas diagnosed by imaging.

For this retrospective study, 241 imaging studies were reviewed from 1998 to 2005. Thirty-one patients met our strict diagnostic imaging inclusion criteria and had at least 18 months of imaging follow-up. Patient demographics and lesion imaging characteristics were tested as predictors of growth.

Growth was measured over a mean period of 42 months. There was a significant (P = .0004) linear growth of tumour for the population. There was significant clustering (P = .001) of the population into 2 growth rates: 0.50 mm/y (n = 23) and 5.5 mm/y (n = 8). The diameter of the lesion at presentation was significantly correlated with growth (r = 0.45; P = .01).

The microcystic subtype of serous cystadenomas of the pancreas diagnosed with imaging criteria demonstrates 2 distinct and slow growth rates. The size of the lesion at presentation is correlated with growth rate.

Frustratingly, sonography to assess for appendicitis in children often leads to an inconclusive report (eg, “suspicious for appendicitis”) or nonvisualization of the appendix. To aid in planning who to image and how to interpret the results, we investigated whether these 2 results were more frequent in teenagers than preteens and the prevalence of appendicitis associated with each result.

We retrospectively reviewed sonographic and surgical findings in patients <18 years (n = 189) referred with clinical suspicion of appendicitis over a 12-month period. Children (≤12.0 years old; n = 86) and teens (>12.0 years old; n = 103) were compared.

Prevalence of appendicitis was 34% in each group, similar to other centres; 0% for those with negative ultrasound reports (0/35), 10% for nonvisualized appendix (8/84), 68% for inconclusive report (15/22), and 85% for positive ultrasound (41/48). Teens were significantly more likely to have an inconclusive ultrasound. Inconclusive reports were because of borderline findings (eg, appendix size near 6 mm; 9/22), body habitus, bowel gas, or unusual findings due in retrospect to perforation. The rate of nonvisualization of the appendix did not vary significantly with age (42% vs 47%).

An inconclusive result of ultrasound for appendicitis was significantly more frequent in teens than in preteens and carried a high (68%) likelihood of appendicitis. Conversely, a nonvisualized appendix was equally frequent in teens and preteens, and had a low likelihood of appendicitis (only 10% positive). These findings encourage the use of ultrasound in preteens in particular and can assist interpretation of these common results.

Previous studies of patients with invasive breast cancer examined, with mixed results, tumour location as a predictor of axillary lymph node metastasis. This study assessed whether tumour location in relation to the nipple impacts the presence of axillary lymph node metastasis at the time of diagnosis.

A retrospective review was undertaken of the medical records and available imaging of 285 patients diagnosed with invasive breast cancer between January 2001 to June 2007 at Boston University Medical Center. The incidence of axillary lymph node metastasis was correlated with tumour location in relation to the posterior nipple line to control for variation in breast size. Bivariate analysis identified significant variables that were applied to a multiple logistic regression model.

Axillary lymph node metastasis was not significantly associated with tumour proximity to the nipple. In the multivariate logistic regression analysis, known prognostic factors for axillary metastasis, such as surgical size, lymphovascular invasion, and age of diagnosis, were significant, whereas breast density, palpability, and histologic grade were no longer significant.

Our study found that there was no evidence that correlates intramammary tumour proximity to the nipple with the presence of axillary lymph node metastasis at diagnosis. However, known prognostic factors, such as lymphovascular invasion, surgical size, and younger age at diagnosis, are strong independent predictors for axillary lymph node involvement.

To assess the sensitivity and specificity of 3 Tesla magnetic resonance imaging (MRI) in the prediction of extramural spread and metastatic adenopathy in rectal carcinoma.

This was a prospective cohort study that included forty consecutive patients with rectal carcinoma from the Department of Colorectal Surgery. Three Tesla (3T) MRI was performed on these patients after a 4-hour fast and cleansing water enema. TI-weighted and T2-weighted images were obtained with high-resolution images T2-weighted sequences through the pelvis. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 3T MRI for prediction of metastatic adenopathy and extramural spread were calculated. The TNM staging based on MRI was compared with histopathology of the resected specimen (taken as the criterion standard).

In our study, sensitivity, specificity, PPV, and NPV of 3T MRI for prediction of metastatic adenopathy were 100%, 78.3%, 77.3%, and 100%, respectively. Sensitivity, specificity, PPV, and NPV of 3T MRI for prediction of extramural tumour spread were 100% and 20%, 89.7% and 100%, respectively (ie, prediction of stages T3 and above).

MRI allows accurate measurement of the depth of extramural tumour spread. In the assessment of metastatic adenopathy, however, MRI has a low specificity. This study shows that MRI is unlikely to miss any significant parameter in staging of rectal carcinoma. However, it has a tendency to overstage extramural spread of tumour.