A new and simple practical plane dividing hepatic segment 2 and 3 of the liver: evaluation of its validity.
OBJECTIVE
The conventional method of dividing hepatic segment 2 (S2) and 3 (S3) is subjective and CT interpretation is unclear. The purpose of our study was to test the validity of our hypothesis that the actual plane dividing S2 and S3 is a vertical plane of equal distance from the S2 and S3 portal veins in clinical situations.


METHODS
We prospectively performed thin-section iodized-oil CT immediately after segmental chemoembolization of S2 or S3 in 27 consecutive patients and measured the angle of intersegmental plane on sagittal multiplanar reformation (MPR) images to verify its vertical nature. Our hypothetical plane dividing S2 and S3 is vertical and equidistant from the S2 and S3 portal veins (vertical method). To clinically validate this, we retrospectively collected 102 patients with small solitary hepatocellular carcinomas (HCC) on S2 or S3 the segmental location of which was confirmed angiographically. Two reviewers predicted the segmental location of each tumor at CT using the vertical method independently in blind trials. The agreement between CT interpretation and angiographic results was analyzed with Kappa values. We also compared the vertical method with the horizontal one.


RESULTS
In MPR images, the average angle of the intersegmental plane was slanted 15 degrees anteriorly from the vertical plane. In predicting the segmental location of small HCC with the vertical method, the Kappa value between CT interpretation and angiographic result was 0.838 for reviewer 1 and 0.756 for reviewer 2. Inter-observer agreement was 0.918. The vertical method was superior to the horizontal method for localization of HCC in the left lobe (p < 0.0001 for reviewers 1 and 2).


CONCLUSIONS
The proposed vertical plane equidistant from S2 and S3 portal vein is simple to use and useful for dividing S2 and S3 of the liver.
Department of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, 38 Yongon-dong, Chongno-gu, Seoul 110-744, Korea.
Ho Yun
HY
Lee
Jin Wook
JW
Chung
Jeong Min
JM
Lee
Chang Jin
CJ
Yoon
Whal
W
Lee
Hwan Jun
HJ
Jae
Yong Hu
YH
Yin
Sung-Gwon
SG
Kang
Jae Hyung
JH
Park
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction; D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage; D006528:Carcinoma, Hepatocellular / Q000098:blood supply / Q000000981:diagnostic imaging / Q000628:therapy; D016461:Chemoembolization, Therapeutic; D003287:Contrast Media; D004317:Doxorubicin / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007459:Iodized Oil; D008099:Liver / Q000098:blood supply* / Q000000981:diagnostic imaging*; D008113:Liver Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012042:Registries; D012189:Retrospective Studies; D036542:Tomography, Spiral Computed
D000903:Antibiotics, Antineoplastic; D003287:Contrast Media; D007459:Iodized Oil; D004317:Doxorubicin