Helical liver CT with computer-assisted bolus-tracking technology: is it possible to predict which patients will not achieve a threshold of enhancement?

PURPOSE: To determine how often a prescribed threshold of hepatic contrast material enhancement is not reached at helical computed tomography (CT) of the liver in patients in a tertiary teaching hospital-based practice and which variables are predictive of failure. MATERIALS AND METHODS: Hepatic helical CT was performed in 250 consecutive patients with computer-assisted bolus-tracking technology after either mechanical injection at 3 mL/sec (n = 177) or manual injection (n = 73) of 150 mL of iopamidol. Demographic variables were recorded. After 17 seconds, low-milliamperage monitoring scans were obtained every 6 seconds until hepatic enhancement of 50 HU over baseline was achieved. Time-enhancement curves were reviewed. RESULTS: The threshold was not reached by 60 seconds in 88 patients (35%; default group). The success and default groups were similar in most variables and differed only in weight (P = .002), patient status (inpatient, outpatient, or emergency department; P < .001), and injection type (mechanical vs manual; P < .001). Ten patients (4%) did not achieve the threshold because of inappropriate placement of elliptic regions of interest. CONCLUSION: By using computer-assisted bolus-tracking technology, 35% of patients in a tertiary teaching hospital-based practice will not achieve a threshold of 50 HU above baseline by 60 seconds after injection initiation and will require the use of a set delay. Failures are more frequent in patients who are heavy and in inpatients. No historic or demographic factors are strongly predictive of failure.

Duke Scholars

Author Erik Karl Paulson Radiology, Abdominal Imaging

Author Rendon C. Nelson Radiology