CT perfusion opens functional window to gastrointestinal tumors

Advances in CT imaging have enabled radiologists to reliably measure functional features related to gastrointestinal tumor vascularity and angiogenesis that help in diagnosing, staging, and monitoring therapy.

Dr. Dushyant Sahani and colleagues at Massachusetts General Hospital reported in the June issue of Radiology the first published study of the role of CT perfusion in hepatocellular carcinoma. In 30 patients with locally advanced HCC, researchers found higher mean values of blood flow, blood volume, and permeability in well-differentiated HCC than in moderately or poorly differentiated tumors. In four patients who had repeat exams, investigators determined CT perfusion was highly reproducible with no significant variability.

Several papers and posters at the European Congress of Radiology highlighted the emerging value of CT perfusion in various gastrointestinal organ systems. Italian researchers from Milan led by Dr. Massimo Bellomi showed in 25 rectal cancer patients that high blood flow and blood volume correlate with tumor volume changes following neoadjuvant chemoradiation therapy.

Japanese researchers from Chiba led by Dr. Takenori Ochiai studied 40 consecutive patients with rectal tumors and found that low blood flow, low blood volume, or long mean transit time correlated with lymph node metastases. The same group studying 30 patients discovered that decreased gastric tumor blood flow correlated with malignancy, especially in those with high-grade malignancy.

Beijing investigators led by Dr. Wei Lui showed in 58 patients that four different types of renal masses-clear cell carcinoma, pelvic transitional cell carcinoma, angiomyolipoma, and simple cyst-all have decreased perfusion characteristics compared with normal tissue.

Dr. Pasquale Paolantonio and colleagues from the University of Rome described their success evaluating tumor neovascularity in the pancreas, bladder, prostate, and rectum.

CT perfusion techniques offer quantitative information that may help to assess malignancy, as well as pathological tumor features, before surgery. Perfusion data also assist in determining the presence of tumor-related arterial neoangiogenesis following therapy.