Application of stereology in liver volume measurements using computed tomography scan / Aplicación de la estereología en mediciones de volumen hepático mediante tomografía computarizada

SUMMARY: The application of stereology in hepatobiliary conditions is essential in liver volume estimation. Computerized topographic scan with contrast is a reliable method in liver scanning for precise boundaries demarcation. Liver volumetry varies in relation to different factors. Reports showed a correlation of liver volume with sex and body mass index. Steady relation between age and ethnicity is not established. This study aimed to design a protocol for liver volume measurement and apply it in the estimation of volume among the Sudanese population use stereology. Recruitment of the study population was obtained in the royal scan clinic in Khartoum by making an announcement for participation in the study. Patients with a history of hepatobiliary diseases were excluded. CT abdomen with contrast was obtained in DICOM format and transferred to computer-based software for image analysis. A protocol was designed and validated and then applied in volume estimation using software MRIcro for image display, ImageJ for volume estimation, and Onis 2.6 as image viewer. 300 apparently healthy volunteers were recruited. The protocol reliability result was 0.805. Absolute mean liver volume was 3261.32 ± 1365.313 cm3. High liver volume among females was detected than among males. A positive correlation was detected between volume and body mass index (p-value 0.001) regardless of sex. Relation with age showed a rough steady rise till the age of 50 years then it started to decline steadily. The relationship was detected in liver volume with sex and body mass index. More studies are needed to investigate the relationship between ethnicity and age groups.

RESUMEN: La aplicación de la estereología en condiciones hepatobiliares es fundamental en la estimación del volumen hepático. El escaneo topográfico computarizado con contraste es un método confiable en el escaneo del hígado para la demarcación precisa de sus límites. La volumetría hepática varía en función de diferentes factores. Los informes mostraron una correlación del volumen del hígado con el sexo y el índice de masa corporal. No se establece una relación estable entre la edad y la etnia. Este estudio tuvo como objetivo diseñar un protocolo para la medición del volumen hepático de la población sudanesa usando la estereología. El reclutamiento de la población de estudio fue realizado en la clínica de exploración real en Jartum mediante un anuncio de participación. Se excluyeron los pacientes con antecedentes de enfermedades hepatobiliares. Se obtuvo TC de abdomen con contraste en formato DICOM y se transfirió a un software informático para el análisis de imágenes. Se diseñó y validó un protocolo y luego se aplicó en la estimación de volumen utilizando el software MRIcro para la visualización de imágenes, ImageJ para la estimación de volumen y Onis 2.6 como visor de imágenes. Se reclutaron 300 voluntarios sanos. El resultado de la fiabilidad del protocolo fue 0,805. El volumen hepático medio absoluto fue 3261,32 ± 1365,313 cm3. Se detectó un volumen más elevado de hígado en las mujeres que en los hombres. Se detectó una correlación positiva entre el volumen y el índice de masa corporal (valor de p 0,001) independientemente del sexo. La relación con la edad mostró un aumento continuo y brusco hasta los 50 años, luego comenzó a disminuir de manera constante. Se detectó la relación del volumen hepático con el sexo y el índice de masa corporal. Se necesitan más estudios para investigar la relación entre la etnia y los grupos etarios.

Variations of Arterial Supply of the Liver: C.T. Angiographic Study Among Sudanese Adults

Hepatobiliary surgery through laparoscopic approach is becoming a routine. Knowledge of extrahepatic arterial tree is essential for surgical and imaging procedures. Anatomical complexity is expected since the liver is developed by mergingof lobules with its separate blood supply. This makes a wide range of variations in the pattern of vascular arrangement and so reinforces the need for an accurate understanding of full spectrum of variations. This study aimed to investigate the variations in origin and distribution of extrahepatic arterial supply. Fifty volunteers (32 males and 18 females) aged 20­70 years were randomly recruited from the department of CT scan in Al Amal Hospital, Khartoum North, Sudan. The patients were already candidates for CT angiography with contrast for conditions other than hepatobiliary diseases. The reported data is related to those who accepted to participate in the study. Patients with history of hepatobiliary disease were excluded. 3D views of the scans were treated and the extrahepatic arterial tree was traced in a computer-based software. Key findings suggest that Michel's classification was considered the standard template for description ­ 76% of them showed Michel's type I classification. Types III and V constituted about 2%. About 4% of the cases were represented by types VI and IX. Other types of variations constituted about 12%. To conclude, although type I classification which describes the textbook pattern of hepatic artery distribution was significantly detected among the Sudanese population, other variants were to be considered since they are related to major arteries like aorta and superior mesenteric.