Shalini Thapar Laroia MD, Presenter: Nothing to Disclose

Shiv Sarin, Abstract Co-Author: Nothing to Disclose

To determine whether spectral CT can improve qualitative and quantitative accuracy in diagnosis of HCC in a cirrhotic liver using material iodine density.  

Routine and spectral CT( at 70-140kVp) was performed for 3600 patients with cirrhosis over a span of 3 years. The indeterminate mass lesions were identified, of which few were followed up and some lesions underwent biopsy/ surgical explantation. These were analyzed using gem stone imaging software at 55keV. The hepatic arterial phase (which showed maximum iodine enhancement) was used to quantify iodine concentrations from iodine-based material-decomposition images. The  lesion iodine to aortic iodine concentration (normalized enhancement values- NEV) and lesion-to-normal parenchyma ratio (LNR)were obtained . Spectral HU curve, Scatter plot and the material density values of the indeterminate lesions were derived and statistically analyzed. 

Total cirrhotic population screened = 3600 Number of patients with HCC =142 Number of indeterminate hypervascular lesions = 82 Number of indeterminate lesions on follow up =40 Number of indeterminate lesions  underwent biopsy/ hepatectomy=42 All indeterminate lesions were studied with spectral imaging in HAP at 55keV: Number of patients with true positive HCC= 34, Number of patients with false positive HCC= 8  

This study reveals that spectral imaging is an excellent add on qualitative and quantitative tool to routine CT for assessing hypervascular and indeterminate lesions in cirrhotic patients.  

1. This data suggests that spectral imaging maybe used to help characterize HCC on a single phase arterial study, thus reducing dosage of both intravenous contrast and radiation. 2. The predictability and accuracy of spectral CT in diagnosis of HCC may be able to reduce, if not completely obviate the need for biopsy in future. 3. The need for second modality confirmation using MRI/ contrast ultrasound of a suspicious lesion showing hypervascularity may in future become obsolete if a standard iodine concentration value on dual energy CT for hepatocellular carcinoma can be deciphered using randomized controlled trials. 4. Predictability of tumor grading is likely to be possible with spectral imaging by assessing the material decomposition analysis. 5. Spectral CT is a  functional test for liver tumours and has a potential to become an excellent Onco-imaging tool.  

Laroia, S, Sarin, S, Dual-energy Spectral CT for Characterization of Hepatocellular Carcinoma: Initial Experience.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045481.html