Liver size is a significant indicator for the presence of a disease process; also, it aids in treatment planning for liver transplantation and resection. In addition, it is used post-therapy for assessment of graft regeneration and treatment response evaluation in case of liver malignancy [1], and it is used after portal vein embolization for evaluation of the increase in future liver remnant volume [15, 16].
Liver volume is a better way for the assessment of liver size as it represents the entire liver rather than linear measurements in single planes [17]. Computed tomography (CT) has been widely used for volumetric assessment of the liver, magnetic resonance imaging (MRI) and ultrasound also, and has shown trustable organ volume measurements in light of appropriate scanning protocols [1].
Many previous studies have tried to evaluate and validate various imaging modalities for liver volumetry; however, there is no clear evidence about the most accurate method [5].
CT volumetry in combination with dedicated software plays important role in the evaluation of candidates for liver donor transplantation as it shows accurate estimation of graft dimension before transplant [18]. It has been performed by manual tracing of the liver boundary and summation of the liver area on each axial section, but this technique is operator dependent and time-consuming.
Although with advanced technology, automated and semi-automated volumetric measurements have been carried out to replace manual liver volumetry for accurate liver volume calculation [3]; however, there is still need for simple and uncomplicated technique that can be trusted for liver volume assessment [10].
Despite the widespread 3D ultrasound and its simplicity in the assessment of liver size, it is not proved to be a successful method for liver volumetric assessment because of its limitations, both physically as it is impractical and time-consuming and also those related to a variable reproducibility of the examination which depends mainly on the examiner skills [19]. Also, in the assessment of liver size by simple linear 2D US, there is a lack of standardization of measurement method and adopted cutoff values with the accepted plane of measurement, and its used cutoff values varies from one department to the other, so most of the previous studies did not report its accuracy [10, 17, 20, 21].
As the single linear liver size measurement by ultrasound represents the liver in only one plane, and the morphologic shape of the liver differs among people, Childs et al. determined the set of practical three simple measurement planes using 2D US, and predictive equation was created from these three measurements to determine the liver volume which is more accurate than the liver size [11].
In this study, the 2D US volumetric assessment of the liver in different age groups and different sexes was done by using Childs et al.’s [14] equation, and the results were compared with semi-automated CT volumetric results as a gold standard.
To our knowledge, Childs et al.’s study [ 19] is the only study which is comparing the results of 2D US volumetric assessment of the liver based on Child et al.’s [14] equation with CT volumetry and reported near perfect agreement (r = 0.9) between the two modalities [11, 19]. This agreed with our study which also reported a strong positive correlation (r = 0.74) with no statistically significant difference found between them (p > 0.05), and no statistically significant difference was found also between them in different age groups and different sexes.
A limitation of this study was that this study was conducted only on normal liver cases, so, in order to generalize the results, further future studies are recommended on diseased liver to validate its accuracy in liver volumetric assessment.