Arthrography of the knee: a comparative study of the accuracy of single and double contrast techniques

Single and double contrast arthrographic techniques were compared in 951 patinets with suspected meniscal injuries. Exploratory surgery of the knee was performed in 384 of these patients and good clinical follow-up was obtained in 135 patients. In the latter two groups of patients, the single contrast technique was 97% accurate in assessing the medial meniscus and 96% accurate in assessing the lateral meniscus. Double contrast arthrography was 97% accurate in assessing the medial meniscus and 93% accurate in assessing the lateral meniscus. Numerical differences in the results from the two techniques were not statistically significant. Therefore both techniques can be considered equally effective diagnostically.     

Detailed per-oral small bowel examination vs. enteroclysis. Part II: Radiographic accuracy

Accuracy of the detailed per-oral small bowel series and enteroclysis was compared in 134 patients known to have (or not have) disease of the small bowel. Overall sensitivity of the per-oral examination was 92% and specificity 94%, compared to 94% and 89%, respectively, for enteroclysis. There was no difference between the two in Crohn disease, adhesions, and metastatic disease; however, enteroclysis was thought to be more effective in delineating peritoneal adhesions in patients with obstruction. The authors conclude that while the per-oral study and enteroclysis are equally valid methods of examining the small bowel, the per-oral study is preferable as a screening examination because it requires less time, has fewer side effects, and involves a lower radiation exposure.     

Loss of primary cilia upregulates renal hypertrophic signaling and promotes cystogenesis

Primary cilia dysfunction alters renal tubular cell proliferation and differentiation and associates with accelerated cyst formation in polycystic kidney disease. However, the mechanism leading from primary ciliary dysfunction to renal cyst formation is unknown. We hypothesize that primary cilia prevent renal cyst formation by suppressing pathologic tubular cell hypertrophy and proliferation. Unilateral nephrectomy initiates tubular cell hypertrophy and proliferation in the contralateral kidney and provides a tool to examine primary cilia regulation of renal hypertrophy. Conditional knockout of the primary cilia ift88 gene leads to delayed, adult-onset renal cystic disease, which provides a window of opportunity to conduct unilateral nephrectomy and examine downstream kinetics of renal hypertrophy and cyst formation. In wild-type animals, unilateral nephrectomy activated the mTOR pathway and produced appropriate structural and functional hypertrophy without renal cyst formation. However, in ift88 conditional knockout animals, unilateral nephrectomy triggered increased renal hypertrophy and accelerated renal cyst formation, leading to renal dysfunction. mTOR signaling also increased compared with wild-type animals, suggesting a mechanistic cascade starting with primary ciliary dysfunction, leading to excessive mTOR signaling and renal hypertrophic signaling and culminating in cyst formation. These data suggest that events initiating hypertrophic signaling, such as structural or functional loss of renal mass, may accelerate progression of adult polycystic kidney disease toward end-stage renal disease.     

Change in cognitive function in Alzheimer's disease in African-American and white persons

Few studies have examined the association of race with change in cognitive function in Alzheimer's disease (AD). We studied the rate of decline in global and specific measures of cognitive function in a cohort of 410 older African-Americans and whites with clinically diagnosed AD. Persons were examined annually for an average of 3.5 years, and follow-up participation among survivors exceeded 90%. In mixed-effects models that controlled for age, gender, education, and premorbid reading activity, African-Americans scored lower than whites at baseline on a composite measure of global cognition and on specific measures of visuoconstruction and naming. However, they experienced less rapid decline in episodic memory (p < 0.01), with similar but not quite significant effects for global cognition (p = 0.06), perceptual speed (p = 0.07) and naming (p = 0.08). The results suggest that the rate of cognitive decline in AD is slower in African-Americans compared with whites, particularly for episodic memory.     

Utilization and Yield of Chest Computed Tomographic Angiography Associated with Low Positive D-dimer Levels

Background

It is unclear to what degree broadly applied D-dimer testing combined with a low threshold for imaging with even minimally positive results may be contributing to the utilization of chest computed tomographic angiography (CTA).

Study Objectives

To determine what proportion of chest CTAs for suspected pulmonary embolism (PE) were performed in the setting of minimally elevated D-dimer levels, and to determine the prevalence of PE in those patients when stratified by clinical risk.

Methods

Retrospective chart review of all patients who had chest CTA for the evaluation of suspected PE during the years 2002–2006 in a suburban community teaching hospital emergency department.

Results

There were 1136 eligible patient visits, of which 353 (31.1%) were found to have D-dimer levels in the low positive range (0.5–0.99 μg/mL). Of these 353 patients, 9 (2.6%; 95% confidence interval [CI] 0.9–4.2%) were diagnosed with PE. There were also 109 patients (9.6%) who had normal D-dimer levels (<0.5 μg/mL). Two of these 109 (1.8%; 95% CI 0–4.2%) were diagnosed with PE. When stratified by the Pulmonary Embolism Rule-out Criteria, 99 of 353 patients with low positive D-dimer levels (28.0%; 95% CI 23.4–32.7%), and 14 of 109 with normal D-dimer levels (12.8%; 95% CI 6.6–19.1%) were classified as low risk, none of whom had PE.

Conclusions

Nearly one-third of all chest CTAs were done for patients with minimally elevated D-dimer levels, and another 9.6% for patients with normal D-dimer levels with very low yield. Further research to define clinical criteria identifying patients with minimal risk of PE despite low positive D-dimer levels represents an opportunity to improve both patient safety and utilization efficiency of chest CTA.