Value of customized scan timing determined by tracking liver enhancement in oncology patients.

PURPOSE: To assess the value of liver parenchyma enhancement tracking for liver multidetector computed tomography (CT) in patients with potential hypoattenuating liver metastases.

MATERIALS AND

METHODS

Institutional review board approved this Health Insurance Portability and Accountability Act-compliant study. We reviewed the chest-abdomen-pelvis CTs of 120 consecutive patients scanned on 16-/64-row multidetector CT after receiving 52 g I in 50 seconds. Liver scanning started 65 seconds after injection-start in 59 patients, whereas in 61 patients, scanning started automatically when liver enhancement reached 50 Hounsfield units on low-dose continuous attenuation tracking. Enhancement of liver parenchyma, aorta, portal, and hepatic veins was measured. Two readers graded conspicuity and recorded attenuation of hypoattenuating lesions.

RESULTS

We identified 663 metastases in 74 patients. Scan-delay range in the triggered group was 53 to 83 seconds. Compared with the fixed-delay group, in the triggered group, mean number of metastases per patient with metastases was larger, liver attenuation and enhancement were higher, and median metastasis conspicuity grade was higher (all P < 0.05).

CONCLUSIONS

Automatic scan triggering based on liver parenchyma enhancement tracking produces consistently higher liver parenchymal enhancement and increased metastasis conspicuity than fixed delay.