Satoshi Goshima MD, PhD, Presenter: Nothing to Disclose

Yoshifumi Noda MD, Abstract Co-Author: Nothing to Disclose

Hiroshi Kondo MD, Abstract Co-Author: Nothing to Disclose

Haruo Watanabe MD, Abstract Co-Author: Nothing to Disclose

Masayuki Kanematsu MD, Abstract Co-Author: Nothing to Disclose

Kyongtae Tyler Bae MD, PhD, Abstract Co-Author: Patent agreement, Covidien AG Consultant, Otsuka Holdings Co, Ltd

To determine the optimal iodine mass (IM) required for the detection of hypervascular hepatocellular carcinoma (HCC) based on total body weight (TBW) and body surface area (BSA) at 80kVp CT imaging of the liver.

IRB approval and written informed consent was obtained. One hundred nine patients with chronic hepatitis (75 men, 34 women; mean age, 67.9 years; range, 41 - 85 years) underwent contrast enhanced CT for screening of HCC. The patients were randomized into three groups according to the following iodine-dose per body-weight protocols: 0.5 gI/kg (0.5 g of iodine per kilogram TBW), 0.4 gI/kg, and 0.3 gI/kg groups. All CT examination were performed with low tube voltage (80kVp), high tube current (with the use of automatic exposure control), and adaptive statistical iterative reconstruction. The three groups were compared in terms of hepatic parenchymal CT enhancement during the portal venous phase (ΔHU) and qualitative score (in a 5-point scale) for the visualization of HCC, if presence, at the hepatic arterial, portal venous, and equilibrium phases. Iodine dose per BSA (gI/m2) was also calculated and compared with ΔHU and visualization of HCC.

Thirty-three HCCs were identified in 30 patients (mean size, 15.2 mm; size range, 5-68 mm). The mean ΔHU for the 0.5 gI/kg group (83.3 HU) was higher than those of the 0.4 gI/kg (63.3 HU) and 0.3 gI/kg (50.0 HU) groups (P < 0.001). The relationship between the enhancement and iodine-dose according to a linear regression analysis was ΔHU = -6.3 + 178.0*IM/TBW (P < 0.001) and ΔHU = 7.4 + 4.1*IM/BSA (P < 0.001). The three groups were comparable in qualitative scores for the visualization of the detected HCCs in hepatic arterial and portal venous phase. 

The iodine dose to achieve the hepatic parenchymal enhancement of 50 HU for the detection of hypervascular HCC was estimated to be 0.32 gI/kg of body weight or 10.5 gI/m2 of body surface area at 80-kVp CT imaging. This dose represents substantially less than the traditional dose of 500 mgI/kg used at higher kVp CT imaging.

Our study estimated the optimal amount of iodine-dose for the detection of hypervascular HCC and confirmed that the iodine-dose could be required significantly less in 80-kVp than in higher kVp CT imaging. This information is useful for designing clinical protocols for hepatic CT imaging.

Goshima, S, Noda, Y, Kondo, H, Watanabe, H, Kanematsu, M, Bae, K, Determining Optimal Iodine Dose with 80-kVp CT Imaging: Detection of Hypervascular Hepatocellular Carcinoma.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14004298.html