Faculty Bibliography

Colorectal cancer is the third leading cause of cancer deaths in the United States. Most colorectal cancers can be prevented by detecting and removing the precursor adenomatous polyp. Individual risk factors for the development of colorectal cancer will influence the particular choice of screening tool. CT colonography (CTC) is the primary imaging test for colorectal cancer screening in average-risk individuals, whereas the double-contrast barium enema (DCBE) is now considered to be a test that may be appropriate, particularly in settings where CTC is unavailable. Single-contrast barium enema has a lower performance profile and is indicated for screening only when CTC and DCBE are not available. CTC is also the preferred test for colon evaluation following an incomplete colonoscopy. Imaging tests including CTC and DCBE are not indicated for colorectal cancer screening in high-risk patients with polyposis syndromes or inflammatory bowel disease. This paper presents the updated colorectal cancer imaging test ratings and is the result of evidence-based consensus by the ACR Appropriateness Criteria Expert Panel on Gastrointestinal Imaging. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

OBJECTIVE:The purpose of this article is to review the most common data analysis methods encountered in radiology-based studies. Initially, description of variable types and their corresponding summary measures are provided; subsequent discussion focuses on comparison of these summary measures between groups, with a particular emphasis on regression analysis. CONCLUSION/CONCLUSIONS:Knowledge of statistical applications is critical for radiologists to accurately evaluate the current literature and to conduct scientifically rigorous studies. Misapplication of statistical methods can lead to inappropriate conclusions and clinical recommendations.

OBJECTIVE:Zolpidem has been reported to cause temporary recovery of consciousness in vegetative and minimally conscious patients, but how often and why this occurs are unknown. The authors aimed to determine the frequency of this phenomenon and whether it can be predicted from demographic and clinical variables. DESIGN/METHODS:This is a placebo-controlled, double-blind, single-dose, crossover study performed by caregivers and replicated by trained professionals, for naive participants. Four previously identified responders were also studied to further characterize the clinical drug response. RESULTS:Eighty-four participants with traumatic and nontraumatic disorders of consciousness of at least 4 mos' duration were studied. Four "definite responders" were identified, but no demographic or clinical features were predictive of the response. Indicators of a drug response included increased movement, social interaction, command following, attempts at communication, and functional object use; typically lasted 1-2 hrs; and sometimes ended with increased somnolence. Adverse events were more common on zolpidem than placebo, but most were rated as mild. CONCLUSIONS:Approximately 5% (4.8%) of the participants responded to zolpidem, but the responders could not be distinguished in advance from the nonresponders. Future research is needed to understand the mechanism of zolpidem in enhancing consciousness and its potential role in treatment and research.

A complete fetal ultrasonographic (US) study includes assessment of the umbilical cord for possible abnormalities. Knowledge of the normal appearance of the umbilical cord is necessary for the radiologist to correctly diagnose pathologic conditions. Umbilical cord abnormalities can be related to cord coiling, length, and thickness; the placental insertion site; in utero distortion; vascular abnormalities; and primary tumors or masses. These conditions may be associated with other fetal anomalies and aneuploidies, and their discovery should prompt a thorough fetal US examination. Further workup and planning for a safe fetal delivery may include fetal echocardiography and karyotype analysis. Doppler US is a critical tool for assessment and diagnosis of vascular cord abnormalities. US also can be used for follow-up serial imaging evaluation of conditions that could result in fetal demise. Recent studies suggest that three- or four-dimensional Doppler US of the fetal umbilical cord and abdominal vasculature allows more accurate diagnosis of vascular abnormalities. Doppler US also is invaluable in assessment of fetal growth restriction since hemodynamic changes in the placenta or fetus would appear as a spectral pattern of increased resistance to forward flow in the fetal umbilical artery. Early detection of umbilical cord abnormalities and close follow-up can reduce the risk of morbidity and mortality and assist in decision making.

Primary peritoneal mesothelioma is a rare neoplasm which carries a dismal prognosis. These highly aggressive tumors arise from mesothelial cells lining the peritoneum and are rapidly fatal. The neoplasm is typically associated with crocidolite asbestos exposure. We present the case of a 75-year-old man with primary peritoneal mesothelioma, with invasion into the right hepatic lobe.

Collectively, cardiac and large artery sources are responsible for the largest proportion of acute ischemic stroke. Technological advancements in computed tomography (CT) continue to improve evaluation of these patients. The literature was reviewed for the potential role and impact of these innovations in evaluation and management of these patients. In conclusion, incorporation of early cardiac and extracranial vascular CT angiography (CTA) in evaluation of patients with acute ischemic stroke may potentially improve patient management and outcome, while decreasing cost.

A fundamental consideration in the workup of a jaundiced patient is the pretest probability of mechanical obstruction. Ultrasound is the first-line modality to exclude biliary tract obstruction. When mechanical obstruction is present, additional imaging with CT or MRI can clarify etiology, define level of obstruction, stage disease, and guide intervention. When mechanical obstruction is absent, additional imaging can evaluate liver parenchyma for fat and iron deposition and help direct biopsy in cases where underlying parenchymal disease or mass is found. Imaging techniques are reviewed for the following clinical scenarios: (1) the patient with painful jaundice, (2) the patient with painless jaundice, and (3) the patient with a nonmechanical cause for jaundice. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

There are a variety of advanced gastrointestinal endoscopic procedures, many of which are guided by endosonography, which are performed by interventional gastroenterologists or minimally-invasive surgeons. The purpose of this pictorial review is to briefly describe several advanced gastrointestinal endoscopically guided procedures, to review the implications for radiologists interpreting the associated imaging examinations, and to demonstrate the expected preprocedural imaging findings, as well as the expected and the unexpected postprocedural findings, in patients undergoing these procedures.