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into an antecubital vein. Images were obtained with the right posterior sectionectomy, and 63.4% and 68.5% in
patient in the supine position, using a gamma camera right hepatectomy, respectively. Segmentectomy was
over a large field of view in which a high-resolution, all- performed to treat the hepatocellular carcinoma.
purpose parallel-hole collimator (Infinia: GE Healthcare
Japan Co. Ltd., Tokyo, Japan) was centered over the Statistical analysis
liver and precordium. Computer acquisition of gamma Values are expressed as means ± standard deviation
camera data was initiated simultaneously with injection (range). The Student’s t test was used to compare
of 99m Tc-GSA and stopped at 30 min. Digital images (128 differences between two groups. A P value of < 0.05
× 128 pixels) were acquired in the byte mode at a rate was significant. All analyses were performed with SPSS
of 2 frames/min for 20 min after the injection. Hepatic version 17 (SPSS, Chicago, IL).
SPECT data were obtained for 15 min after the end of the
dynamic scintigraphic study. RESULTS

3D- 99m Tc-GSA scintigraphy/vascular fusion The clinical characteristics of the 15 patients are
imaging using SYNAPSE VINCENT summarized in Table 1. The mean values of HH15 and
Data obtained by 99m Tc-GSA scintigraphy and CT imaging LHL15 were 0.64 ± 0.10 and 0.90 ± 0.06, respectively.
are composited by adjusting the axial and coronal images, The % GSA (17.9% ± 16.7%) was significantly lower than the
and 3D- 99m Tc-GSA scintigraphy/vascular fused images are % CT (21.5% ± 17.6%) (P < 0.036). In all except 2 patients,
constructed. The 3D-vascular images are used to select the % GSA was lower than the % CT. The discrepancy ratio
the portal venous branch to be resected and to calculate ranged from -4% to 75% (median, 20.7%).
the extraction volume and ratio of the dominant region
of the branch (conventional volumetry). In 3D- 99m Tc- DISCUSSION
GSA scintigraphy, the functional volume and ratio of
the same region are calculated (functional volumetry) Our study demonstrated that 3D- 99m Tc-GSA scintigraphy/
concomitantly. Count-rates are displayed on the images, vascular fusion imaging using SYNAPSE VINCENT is useful
which can be saved. [4] for noninvasive functional liver volumetry in patients
scheduled to undergo various patterns of hepatectomy.
Image analysis
In 99m Tc-GSA scintigraphy, regions of interest (ROI) over Postoperative liver failure remains a life-threatening
the entire liver and heart are delineated. Time-activity complication after hepatectomy. Conventionally,
curves are generated for the ROI. traditional liver function tests and CT volumetry have
been used to evaluate patients before hepatic surgery.
An index of clearance of 99m Tc-GSA from the blood is
calculated as the quotient of the radioactivity of the The use of 99m Tc-GSA scintigraphy to evaluate liver
heart ROI 15 min after injection (H15) divided by the function was initially introduced by investigators
radioactivity of the heart ROI 3 min after injection (H3), in Japan. 99m Tc-GSA is binds to the ASGP-R located
(HH15=H15/H3). Hepatic uptake ratio of 99m Tc-GSA is specifically on hepatocytes. The function of ASGP-R
calculated by dividing the radioactivity of the liver ROI at remains normal even in regenerating hepatocytes, and
15 min (L15) by the sum of H15 and L15 (LHL15) =L15/ the ASGP-R density per hepatocyte is constant. Therefore
[H15+L15]. [10,11,18] the total amounts of ASGP-R are lower in cirrhotic liver
patients than in normal liver patients according to the
The 3D-99mTc-GSA scintigraphy/vascular fusion images hepatocyte theory. [19-23] We previously reported that, with
obtained using SYNAPSE VINCENT are used to calculate the progression of hepatic functional degeneration, ASGP-R
total liver volume without tumor, the conventional volume density per hepatic volume decreases, especially in
ratio of the planned resection region without tumor (% CT), the right lobe. The hepatic accumulation of 99m Tc-GSA
[9]
and the functional volume ratio of the planned resection thus reflects the functional liver volume. The hepatic
[24]
region without tumor (% GSA). The discrepancy ratio is uptake image of 99m Tc-GSA at 15 min or later reflects the
calculated as follows: discrepancy ratio = 100 - % GSA/% CT ASGP-R population. [25] An index of clearance of 99m Tc-GSA
×100 (%). (HH15) is calculated as the quotient of the radioactivity
of the heart ROI 15 min after injection (H15) divided by
Case 9 the radioactivity of the heart ROI 3 min after injection
A 71-year-old woman was admitted with a diagnosis of (H3), (HH15 = H15/H3). Hepatic uptake ratio of 99m Tc-
hepatocellular carcinoma concomitant with liver cirrhosis GSA (LHL15) is calculated by dividing the radioactivity of
due to autoimmune hepatitis. CT revealed hepatocellular the liver ROI at 15 min (L15) by the sum of H15 and L15
carcinoma (hypervascular tumor) in Segment 6 [Figure 1]. The % (LHL15=L15/[H15+L15]). [10,11,18] HH15 and LHL15 reflect
CT and % GSA were 3.0% and 2.2% in partial hepatectomy, the hepatic function. Various studies of 99m Tc-GSA have
12.2% and 11.7% in segmentectomy, 27.5% and 28.4% in examined hepatic function. [9,10,26-28]
Hepatoma Research | Volume 2 | July 1, 2016 189