Diagnostic accuracy of portal-phase CT and MRI with mangafodipir trisodium in detecting liver metastases from colorectal carcinoma.

AIM: To compare the diagnostic accuracy of single section spiral computed tomography (CT) and magnetic resonance imaging (MRI) with tissue-specific contrast agent mangafodipir trisodium (MnDPDP) in the detection of colorectal liver metastases. MATERIAL AND METHODS: One hundred and twenty-five consecutive patients undergoing surgery for primary and/or metastatic disease were evaluated using CT (5 mm collimation and reconstruction interval, pitch 2), two-dimensional fast spoiled gradient echo (2D FSPGR) T1 and single shot fast-spin echo (SSFSE) T2 weighted breath-hold MRI sequences, performed before and after intravenous administration of MnDPDP. The reference standards were intraoperative ultrasound and histology. RESULTS: The per-patient accuracy of CT was 72.8 versus 78.4% for unenhanced MRI (p = 0.071) and 82.4% for MnDPDP-enhanced MRI (p = 0.005). MnDPDP-enhanced MRI appeared to be more accurate than unenhanced MRI but this was not significant (p = 0.059). The sensitivity of CT was 48.4% versus 58.1% for unenhanced MRI (p = 0.083) and 66.1% for MnDPDP-enhanced MRI (p = 0.004). The difference in specificity between procedures was not significant. The per-lesion sensitivity was 71.7, 74.9 and 82.7% for CT, unenhanced MRI, and MnDPDP-enhanced MRI, respectively; the positive predictive value of the procedures was respectively 84.0, 96.0 and 95.8%. MnDPDP-enhanced MRI provided a high level diagnostic confidence in 92.5% of the cases versus 82.5% for both unenhanced MRI and CT. The kappa value for inter-observer variability was >0.75 for all procedures. CONCLUSIONS: The diagnostic accuracy and sensitivity of MnDPDP-enhanced MRI is significantly higher than single section spiral CT in the detection of colorectal cancer liver metastases; no significant difference in diagnostic accuracy was observed between unenhanced MRI and MnDPDP-enhanced MRI.

CT colonography: screening in individuals at high risk for colorectal cancer.

The use of computed tomographic colonography (CTC) as a screening test for colorectal cancer is being advocated with growing enthusiasm by physicians and the public as stronger evidence of its validity and limited invasiveness emerges from the literature. Because the approach to surveillance of colorectal cancer depends on an individual's degree of risk category, which depends on familial and personal histories, it seems logical that the diagnostic performance and cost efficacy of screening CTC may differ according to the characteristics of the target population. Although CTC seems a valid option in low- to average-risk populations, pending a careful assessment of its cost and estimates of its cost efficacy, there are some important issues that should be addressed when it comes to considering its use in high-risk patients. The expected larger number of induced colonoscopies and higher false-positive rates are likely to have a great influence on CTC costs, but if its implementation causes a dramatic increase in the number of patients willing to undergo screening, thanks to its acceptability, then the cost efficacy ratio may ultimately become competitive with all other screening strategies for colorectal cancer. We strongly feel that large and well-conducted trials are needed to clarify the role of CTC in screening patients at increased risk of developing colorectal cancer.

Ileocecal valve imaging on computed tomographic colonography.

BACKGROUND: The aim of our study was to describe the visualization, normal anatomy, and variations of the ileocecal valve with computed tomographic (CT) colonography to provide information about its optimal imaging. METHODS: We analyzed data in two- and three-dimensional rendering mode in 71 consecutive patients who underwent routine CT colonoscopy followed by conventional colonoscopy for confirmation of the radiologic findings. RESULTS: Complete visualization of the ileocecal valve was better achieved in the supine than in the prone position (82% vs. 62%, respectively); the ileocecal valve appeared in 64% of cases in the supine position when it was invisible in prone position (p < 0.0001). Partial visualization of the ileocecal valve was possible in 94% of cases. The ileocecal valve was of labial type in 76%, papillary type in 21%, and lipomatous in 3% of cases. The orifice was identified in 53% of ileocecal valves; in two cases of cecal carcinoma, the normal ileocecal valve morphology was grossly disrupted. CONCLUSION: The ileocecal valve was at least partly visualized by CT colonoscopy in 94% of cases, more frequently in the supine position. Its most common normal morphology is the labial type. The absence of orifice visualization alone is not a specific sign for neoplasia, but its presence helps distinguish physiologic bulging from neoplasia.

HIV-1 transmission in injection paraphernalia: heating drug solutions may inactivate HIV-1.

In response to recent concerns about risk of HIV-1 transmission from drug injection paraphernalia such as cookers, ethnographic methods were used to develop a descriptive typology of the paraphernalia and practices used to prepare and inject illegal drugs. Observational data were then applied in laboratory studies in which a quantitative HIV-1 microculture assay was used to measure the recovery of infectious HIV-1 in cookers. HIV-1 survival inside cookers was a function of the temperature achieved during preparation of drug solutions; HIV-1 was inactivated once temperature exceeded, on average, 65 degrees C. Although different types of cookers, volumes, and heat sources affected survival times, heating cookers 15 seconds or longer reduced viable HIV-1 below detectable levels.