Publications

PURPOSE

In this study, we compare an abbreviated screening MRI protocol (aMRI), utilizing only dynamic contrast-enhanced images, to a conventional liver MRI (cMRI) for the characterization of observations in at-risk patients.

MATERIALS AND METHODS

164 consecutive HCC screening MRIs were retrospectively analyzed. Two sets of de-identified image sets were created: one with all acquired sequences including T2- and diffusion-weighted sequences (cMRI), and one with only T1-weighted precontrast and dynamic post-contrast images utilizing an extracellular gadolinium contrast agent (aMRI). Three readers assigned a LI-RADS score based on the lesion with the highest LI-RADS category using the aMRI and cMRI datasets during separate reads.

RESULTS

There was no change between the aMRI and cMRI LI-RADS categorization in 93%, 96%, and 96% of cases for readers 1, 2, and 3, respectively. In the majority of the discrepant cases, the score increased from LI-RADS 3 to LI-RADS 4 due to the presence of ancillary features on T2 and DWI. Kappa values for interobserver variability demonstrated fair-to-moderate LI-RADS agreement among the 3 readers.

CONCLUSION

There was strong agreement between the abbreviated T1-only MRI protocol and a full liver MRI, with only 5% of cases changing LI-RADS categorization due to the inclusion of T2 and DWI. The estimated time to run this abbreviated MRI is approximately 7-10 min, possibly allowing for a more cost-effective screening MRI than our cMRIs.

RATIONALE

Colorectal cancer (CRC) is preventable through screening, with colonoscopy and fecal occult blood testing comprising the two most commonly used screening tests. Given the differences in complexity, risk, and cost, it is important to understand these tests' comparative effectiveness.

STUDY DESIGN

The CONFIRM Study is a large, pragmatic, multicenter, randomized, parallel group trial to compare screening with colonoscopy vs. the annual fecal immunochemical test (FIT) in 50,000 average risk individuals. CONFIRM examines whether screening colonoscopy will be superior to a FIT-based screening program in the prevention of CRC mortality measured over 10 years. Eligible individuals 50-75 years of age and due for CRC screening are recruited from 46 Veterans Affairs (VA) medical centers. Participants are randomized to either colonoscopy or annual FIT. Results of colonoscopy are managed as per usual care and study participants are assessed for complications. Participants testing FIT positive are referred for colonoscopy. Participants are surveyed annually to determine if they have undergone colonoscopy or been diagnosed with CRC. The primary endpoint is CRC mortality. The secondary endpoints are (1) CRC incidence (2) complications of screening colonoscopy, and (3) the association between colonoscopists' characteristics and neoplasia detection, complications and post-colonoscopy CRC. CONFIRM leverages several key characteristics of the VA's integrated healthcare system, including a shared medical record with national databases, electronic CRC screening reminders, and a robust national research infrastructure with experience in conducting large-scale clinical trials. When completed, CONFIRM will be the largest intervention trial conducted within the VA (ClinicalTrials.gov identifier: NCT01239082).

Controlling malaria in high transmission areas, such as much of sub-Saharan Africa, will require concerted efforts to slow the spread of drug resistance and to impede malaria transmission. Understanding the fitness costs associated with the development of drug resistance, particularly within the context of transmission, can help guide policy decisions to accomplish these goals, as fitness constraints might lead to decreased transmission of drug-resistant strains. To determine if resistance-mediating polymorphisms impact on development at different parasite stages, we compared the genotypes of parasites infecting humans and mosquitoes from households in Uganda. Genotypes at 14 polymorphic loci in genes encoding putative transporters ( and and folate pathway enzymes ( and were characterized using ligase detection reaction-fluorescent microsphere assays. In paired analysis using the Wilcoxon signed-rank test, prevalences of mutations at 12 loci did not differ significantly between parasites infecting humans and mosquitoes. However, compared with parasites infecting humans, those infecting mosquitoes were enriched for the 86Y mutant allele ( = 0.0001) and those infecting s.s. were enriched for the 86Y ( = 0.0001) and 76T ( = 0.0412) mutant alleles. Our results suggest modest directional selection resulting from varied fitness costs during the life cycle. Better appreciation of the fitness implications of drug resistance mediating mutations can inform optimal malaria treatment and prevention strategies.