COMPARATIVE EVALUATION OF HOUNSFIELD UNIT MEASUREMENTS IN LIVER AND SPLEEN PARENCHYMA USING RADIANT DICOM AND UVIEWER

Abstract

Background: Quantitative Hounsfield Unit (HU) measurement of abdominal parenchymal organs is widely used in diagnostic and research applications of contrast-enhanced computed tomography (CT). Although HU values are theoretically standardized, software-dependent factors such as region-of-interest (ROI) rendering, image interpolation, and display calibration may introduce systematic differences between DICOM viewing platforms. This study compared liver and spleen parenchymal HU measurements obtained using RadiAnt DICOM viewer and uViewer on identical portal venous phase abdominal CT datasets.

Methods: Fifty contrast-enhanced abdominal CT examinations (portal venous phase) were retrospectively analysed. A single observer placed standardized circular ROIs on the liver and spleen parenchyma, avoiding vessels, ducts, and artefacts, and independently re-measured the same anatomical slices using RadiAnt DICOM and uViewer. Normality of paired differences was assessed using the Shapiro–Wilk test. Paired-samples t-tests compared mean HU values between viewers, and Pearson's correlation evaluated inter-software agreement.

Results: Mean liver HU was 86.32 ± 9.99 with RadiAnt DICOM versus 103.76 ± 13.95 with uViewer, a statistically significant difference (t = −7.03, df = 49, p < 0.001) with negligible correlation (r = −0.047, p = 0.745). Mean spleen HU was 131.32 ± 17.73 with RadiAnt DICOM versus 127.78 ± 17.21 with uViewer, a non-significant difference (t = 1.10, df = 49, p = 0.275) with weak correlation (r = 0.159, p = 0.272).

Conclusion: Liver HU measurements differed significantly and were poorly correlated between RadiAnt DICOM and uViewer, whereas spleen HU values were statistically comparable but likewise poorly correlated. HU values generated by different DICOM viewers should not be considered directly interchangeable, and viewer-specific calibration verification is recommended before quantitative HU data are pooled across platforms in clinical or research settings.