Computed tomographic virtual colonoscopy to screen for colorectal neoplasia in asymptomatic adults.

BACKGROUND: We evaluated the performance characteristics of computed tomographic (CT) virtual colonoscopy for the detection of colorectal neoplasia in an average-risk screening population. METHODS: A total of 1233 asymptomatic adults (mean age, 57.8 years) underwent same-day virtual and optical colonoscopy. Radiologists used the three-dimensional endoluminal display for the initial detection of polyps on CT virtual colonoscopy. For the initial examination of each colonic segment, the colonoscopists were unaware of the findings on virtual colonoscopy, which were revealed to them before any subsequent reexamination. The sensitivity and specificity of virtual colonoscopy and the sensitivity of optical colonoscopy were calculated with the use of the findings of the final, unblinded optical colonoscopy as the reference standard. RESULTS: The sensitivity of virtual colonoscopy for adenomatous polyps was 93.8 percent for polyps at least 10 mm in diameter, 93.9 percent for polyps at least 8 mm in diameter, and 88.7 percent for polyps at least 6 mm in diameter. The sensitivity of optical colonoscopy for adenomatous polyps was 87.5 percent, 91.5 percent, and 92.3 percent for the three sizes of polyps, respectively. The specificity of virtual colonoscopy for adenomatous polyps was 96.0 percent for polyps at least 10 mm in diameter, 92.2 percent for polyps at least 8 mm in diameter, and 79.6 percent for polyps at least 6 mm in diameter. Two polyps were malignant; both were detected on virtual colonoscopy, and one of them was missed on optical colonoscopy before the results on virtual colonoscopy were revealed. CONCLUSIONS: CT virtual colonoscopy with the use of a three-dimensional approach is an accurate screening method for the detection of colorectal neoplasia in asymptomatic average-risk adults and compares favorably with optical colonoscopy in terms of the detection of clinically relevant lesions.

The efficacy of ultrasound in the evaluation of dynamic scapholunate ligamentous instability.

BACKGROUND: The accuracy of diagnostic imaging modalities that are currently used to evaluate dynamic scapholunate ligamentous instability is equivocal. Ultrasound is commonly used for a wide variety of diagnostic purposes in orthopaedics. The purpose of the present study was to determine the efficacy of ultrasound in the diagnosis of dynamic scapholunate ligamentous instability. METHODS: Two groups of individuals were prospectively studied. Group A included patients with a clinical diagnosis of unilateral dynamic scapholunate ligamentous instability, and Group B included asymptomatic volunteer control subjects. Dynamic ultrasound examinations of the dorsal portion of the scapholunate ligament in both wrists of all individuals were performed by radiologists. The radiologists were blinded with regard to the group to which each person belonged as well as with regard to the affected wrist in the patients in Group A. Arthroscopic examinations of the affected wrist in all of the patients in Group A were then performed by surgeons who were blinded with regard to the results of the ultrasound examination, and the results of the arthroscopic and ultrasound examinations were compared. The ability of ultrasound to discern asymptomatic from symptomatic individuals was also determined. RESULTS: Over a period of 1.5 years, a total of sixty-four wrists were evaluated in fourteen patients (Group A) and eighteen normal subjects (Group B). All fourteen nonaffected wrists in Group A and all thirty-six wrists in Group B were correctly identified as normal with use of ultrasound. Of the fourteen affected wrists in Group A, thirteen were found to have scapholunate ligament laxity on the basis of arthroscopy (twelve wrists) or arthrotomy (one wrist); six of these thirteen wrists had been correctly identified as abnormal with use of ultrasound (a true-positive result), and seven had false-negative results. There was one true-negative result. The ability of ultrasound to differentiate between normal and abnormal wrists was significant (p < 0.001). For the sixty-four wrists, statistical analysis revealed that ultrasound had a sensitivity of 46.2%, a specificity of 100%, and an accuracy of 89.1%. CONCLUSIONS: We conclude that ultrasound has a high specificity and accuracy but a low sensitivity for the evaluation of dynamic scapholunate ligamentous instability, and we recommend its use as an adjunct to other diagnostic modalities for this purpose.

Ancillary services in the health care industry: is Six Sigma reasonable?

Within the naval medical center construct, the disparate disciplines encompassed within ancillary services lend themselves to formal quality analysis and process improvement. This analysis uses the Six Sigma approach. Error rates were investigated and calculated for various processes within ancillary services at Naval Medical Center, San Diego. These were translated into the common metric of defects per million opportunities (DPMO). DPMO rates vary between 21.5 and 420,000. These correspond to Sigma values from 1.7 to approaching 6. Rates vary with biological complexity of the system and the degree of automation available. Some ancillary services translate well into a Six Sigma schema. Systems with high potential patient risk if performed poorly and those amenable to second checking and computer oversight may be candidates for such optimization. This should be undertaken in a local environment conducive to individual error reporting, and in a corporate environment with the will and funding to support the transition.