Optimization of imaging diagnosis of 1-2 cm hepatocellular carcinoma: an analysis of diagnostic performance and resource utilization.

BACKGROUND & AIMS: To determine the optimal imaging scan or combinations in terms of diagnostic performance and resource utilization for 1-2 cm nodules found on surveillance for hepatocellular carcinoma.
METHODS: Eighty-four cirrhotic patients with 101, 1-2 cm nodules (34 malignant, 67 non-malignant) prospectively underwent standardized contrast-enhanced ultrasound, CT, and MRI scans. Sensitivity/specificity and potential imaging/biopsy utilization of individual imaging modalities and two-modality combinations performed at the same time (coincidental) or in sequence were measured. Final diagnosis was determined by biopsy (23), growth (10), recurrence (1), or stability in size for ≥ 18 months (67).
RESULTS: For single imaging scans, sensitivities/specificities ranged between 53-62% and 91-100%. When two scans were combined requiring both to be positive, sensitivities/specificities ranged between 29-41% and 99-100%. When two scans were combined sequentially, requiring only one to be positive, sensitivities/specificities ranged between 74-89% and 91-99%. When comparing combination of two positive tests (MRI and CT) to MRI alone, there was a significant drop in sensitivity (41% vs. 62%, p=0.02), no change in specificity (both 100%), with twice as many scans performed, and 9% rise in potential biopsies or 7% rise in follow-up scans. When comparing the combination of MRI then CT (if MRI negative) to MRI alone, there was an insignificant rise in sensitivity (74% vs. 62%, p=0.13), drop in specificity (97% vs. 100%), with 77% more scans performed, and 6% drop in potential biopsies or 7% drop in potential follow-up scans.
CONCLUSIONS: Single imaging scans have similar specificity to two coincidental positive scans with much less resource utilization. Sequential imaging provides the best sensitivity but with diminished specificity.