The Clinical Anatomical Study Of Volume Measurement And Hepatic Fissure Location Of Right Lobe Of Liver

With the appearance of accurate medical and personalized medical concept and with the continuous improvement of clinical medical technology,the precision liver medical is increasingly valued.In clinical,it has become a research hotspot that to carry out the accurate liver resection based on hepatic segmental anatomy so that to ensure the anatomical integrity of the remnant liver and the volume maximum of functional liver.The volume measurement and evaluation of liver lobe and segment is an urgent requirement for liver surgery.In clinic,CT and MRI are the most widely used techniques in the measurement of liver volume.Some studies showed that compared with the actual volume of the liver,the difference of measurement results of CT,MRI was close to the practical situation.But inconsistency was still found between the measurement results used by CT or MRI and the actual situation in the operation process.At the same time,more and more scholars have questioned the Couinaud's hepatic segmental classification.Both the highest proportion of positioning error and the deviation of maximum distance are happened in the right hepatic lobe subdivided.In the past studies most scholars focused on the location error of the liver segment imaging,the amount of the segmental error and whether it is in accordance with the Couinaud's hepatic segmental classification.However,the reasons for the occurrence of the error are rarely mentioned.And with the development of right posterior lobe liver transplantation and precise hepatectomy,it is eagerly need that to accurate description the shape and spatial position of the right hepatic interlobular fissure.This study was carried out in order to explore the reasons of the inconsistency in the right lobe of liver between the volume measurement and appearance in the operation and describe to the shape of right interlobular fissure.Many techniques were adopted in this study,such as the multicolor segmental infusion combined with plastinated slices technique,CT scaning,Photoshop CS5 and AutoCAD.The area of segment and lobe of right liver were measured.The hepatic segments and lobes were divided according to two kinds of criterion,the radiological boundary(RB)and real anatomical boundary(AB)respectively.After that,the volumes of hepatic right anterior lobe and right posterior lobe were calculated and compared.Furthermore,the sectional area were measured according to the radiological boundary of the hepatic lobe,meanwhile the deviation of the radiological boundary was calculated layer by layer,in order to expose the cause of error in radiological imaging measurement.To better demonstrate the morphology of the right interlobular fissure of the liver,three dimensional visualization model is established used MIMICS software to display the segments and interlobular fissure of hepatic right lobe.Moreover,the clinical liver CT images were retrospectively studied to observed the hepatic right interlobular fissure.The results of this study would provide more reliable morphological basis and data reference for the location diagnosis,preoperative evaluation and treatment plan formulation in clinic.Part ?Materials and methods:The multicolor segmental infusion combined with plastinated slices technique was used in this study to make out the liver slices with hepatic segments differentiated via the multicolor.Then these liver slices were photographed layer by layer.After that,software Photoshop CS5 and Adobe Illustrator CS5 were used in the image registration.These hepatic segments in liver slices were marked by the radiological segmental boundaries on every layer.The images were imported into software AutoCAD.And the area and volume of hepatic segments of right liver on these slices marked by two kinds of boundarying methods,the radiological boundary and the real anatomical boundary,was measured and calculated respectively.The software Spss 13.0 was used to data analysis of the area and volume of hepatic segments and lobes.Results:1.The volume of right lobe of the liver:737.15± 220.30 cm~3 according to radiological boundary 705.27±178.82cm~3 according to anatomical boundaryThe volume of right anterior lobe of the liver:412.86±99.68cm~3 according to radiological boundary 417.41±138.19cm~3 according to anatomical boundaryThe volume of right posterior lobe of the liver:325.14± 136,78cm~3 according to radiological boundary 289.32 ± 89.71cm~3 according to anatomical boundary2.There are no significant difference in the volume of the hepatic right anterior lobe and the hepatic right posterior lobe by using the two division methods of radiological boundary and real anatomical boundary.Part ?During the course of area measurements in the first part,it was found that there was obvious difference between the radiological boundary and real anatomical boundary.And these differences existed almost on every slice.But the result of data comparison showed that no significant differences were found between the two groups of data.In order to expose the cause of above contradiction,the area deviation resulted from the radiological boundary of the hepatic lobe was further calculated by data analysis layer by layer.Materials and methods:Calculate the area deviation amount of hepatic right anterior lobe and posterior lobe layer by layer.The area deviation amount is subtracted from value measured according to the radiological boundary by value measured according to the real anatomical boundary.It can be expressed by formula.Sd =SRB-SAB.In addition,the error rate(ER)was calculated by formula.ERs=|SRB-SAB|/SRB.Then curves of the error value and error rate were set up by dotting the error value or rate at the Y-axis,the number of layers at the X-axis for the right anterior lobe and the right posterior lobe,respectively.Results:1.The Sd curve of right anterior lobe showed a sine curve like shape.But,the curve of Sd of right posterior lobe was half cycles ahead to that of right anterior lobe,and showed a complementary graphics with the curve of right anterior lobe.The results show that a part of right anterior superior segment(segment ?)is divided into right posterior superior segment(segment ?)at the cranial layers by the radiological boundary,and a part of right posterior inferior segment(segment ?)is divided into right anterior inferior segment(segment ?)at the caudal layers by the radiological boundary.2.The ERs curve of right anterior lobe and posterior lobe were U-like or V-like shapes.It indicated that the ERs of the two lobes are high at cranial and caudal layers,but low at middle layers.Conclusion of the part ? and the part ?:1.Multicolor segmental infusion liver slice is a useful method of showing the liver segment and intersegmental boundaries and liver volume measurement.2.The right anterior superior segment(segment ?)is smaller than the actual size,while the right posterior superior segment(segment ?)is larger than the actual size located by radiological boundary in CT images.And the right anterior inferior segment(segment ?)is larger than the actual size,while the right posterior inferior segment(segment ?)is smaller than the actual size located by radiological boundary in CT images.3.Because of the offset of measurement error in cranial and caudal layers,the volume of the right anterior lobe or right posterior lobe displays an analysis results with no significant difference between the radiological boundary and real anatomical boundary.4.On the middle levers of liver section,it is reliable that locating the hepatic right interlobular fissure by radiological landmark.But on the cranial and caudal levers of liver section,there is significant error of locating the hepatic right interlobular fissure by radiological landmark.Part ?In this part of the study,three dimensional reconstruction technique was applied to display segments and fissures of the right hepatic lobe.Materials and methods:Image segmentation of the photoes of liver slices was performed by software Adobe Photoshop CS5.Every segment was distinguished by its color infused.Then the images were imported into software MIMICS,and the segments and interlobular fissure of right hepatic lobe were reconstructed.Results:1.The right interlobular fissure appears gradually as the liver slice image layers move downward.The fissure lies in the posterior of the liver on the cranialy,and move forward with the image layer moving downward to the caudally.On the cranial levers,the fissure is located in a coronal section,and on the caudal levers,the fissure began to rotate laterally.2.The hepatic segments,lobes and interlobular fissures can be clearly displayed as a three dimensional model reconstructed by software MIMICS.3.In space relationship,the right anterior lobe is anterosuperior to the right posterior lobe.The right interlobular fissure is a inclined and laterally rotated plane from posterosuperior part of right lobe downward and forward.There are many small rugged hepatic tissues overlapping from two lobes in this fissure.Part ?To observe the hepatic right interlobular fissure by CT images in clinic.Materials and methods:In this part,a 25 cases retrospective study on CT enhancement images of liver was performed.Sectional liver images were collected using by American GE company 128 row 64 slice spiral CT,and measured in and analysed at GE CT workstation.Three dimensional imaging were reconstructed using MIP and VR method.Observe and measure the hepatic right interlobular fissure.Results:1.Observation and measurement in axial section imagesThe middle hepatic fissure located by radiological landmark inclined an average angle 51° from the sagittal plan to the right.It was an average angle 48° on MIP construction imaging.And there is no significant difference between these two results.Act as the location landmark,the middle point of the gallbladder fossa was consistent with the middle hepatic fissure in a rate of 88%.With the location by radiological landmark,the right hepatic fissure had an average angle 97.8° with sagittal plan.And it was an average angle 116.5° from the sagittal plan on MIP construction imaging.There is a significant difference between these two results.Furthermore,not all axial MIP image could display the right anterior branch and right posterior branch of portal vein on one construction imaging.The cross of these two group branch of portal vein appeared when the thick of reconstruction was increased.2.Observation and measurement in sagittal section images There is a deficient blood vessel region between the right anterior branch and right posterior branch of portal vein,which is the right hepatic interlobular fissure.On the sagittal plane of MIP imaging,the fissure was near the back of the liver on the cranial levels,and near the front of the liver on the caudal levels.The fissure had an average angle 32.97°(range 2.6 °?58.4 °)with the coronal section..When this angle was relatively large,the diaphragmatic dome part of liver was all belong to right anterior superior segment(segment VIII)and caudal part of liver was all belong to right posterior inferior segment(segment VI).In this condition,the right anterior lobe was anterosuperior to the right posterior lobe.When this angle is very small,that means the right hepatic fissure close to the coronary plane.In this condition,the right anterior lobe was anterior to the right posterior lobe.3.With one CT image section downward,the right hepatic fissure stablely moves forward in a distance(D)D=cot a×Scan layer thickness of CT(mm).Conclusion of the part three and the part four:1.The right hepatic fissure can be better display on the sagittal images by MIP reconstruction2.The right interlobular fissure is a inclined and external rotated plane from posterosuperior part of right lobe downward and forward.3.It is helpful to locate the right interlobular fissure on the CT images without obvious landmarks by the oblique angle of the right interlobular fissure on the sagittal plane.4.When the angle between the right interlobular fissure and the coronary plane was relatively large,the right anterior lobe was anterosuperior to the right posterior lobe.And when this angle was very small,the right anterior lobe was anterior to the right posterior lobe.