Estimation of Range of Hounsfield Unit on CT for Different Grades of Fatty Infiltration of Liver Categorized Using Ultrasound

Rahman, Jumana and Yadav, Sushil and Prakashini, K and Kotian, Rahul P (2015) Estimation of Range of Hounsfield Unit on CT for Different Grades of Fatty Infiltration of Liver Categorized Using Ultrasound. GJRA -Global Journala for Research Analysis, 4 (6). pp. 337-340. ISSN 2277-8160

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Abstract

Introduction: Fatty liver disease describes the discrete accumulation of triglycerides within cytoplasmic vesicles of hepatocytes. Ultrasound is the first-line imaging technique for the diagnosing and grading of patients with fatty liver. The CT method employed realizes that the lower the mean liver attenuation or CT number in Hounsfield units (HU), the lower the tissue density and hence the greater the fat content. Therefore, liver density (attenuation in HUs) is inversely related to liver fat. . On unenhanced computed tomography (a), liver density less than 40 Hounsfield units (HU) or a density difference of more than 10 HU between spleen and liver indicates fatty liver. To help prevent diagnostic errors and guide appropriate work-up and management, radiologists should be aware of the different patterns of fat accumulation in the liver, especially as they are depicted at ultrasonography or computed tomography. Aim: Estimation of range of Hounsfield unit on CT for different grades of fatty infiltration of liver categorized on Ultrasound. Objective: To find out the relation between Hounsfield unit and fatty changes of the liver. Materials and methods: The patients who were found to have fatty liver by ultrasound examination were included in this cross sectional study. From these, 30 patients were selected for each grading and the ultrasound results were compared with the HU measurements observed from CT. Kruskalwallis test was used to analyse the data, and the p value < 0.001 indicates statistically significant HU between grades of fatty liver 'The HU of spleen and liver were also compared and it was found that there was a significant HU difference between them. Results: The mean age of the patients who had fatty liver was found to be 45. the median value of grade 1was 37.48 HU and 25% of observations have value less than 36.22 HU(quartile 1),75 %of observations have value less than 38.98 HU. Grade 2 patients median value was 24.48 HU (quartile 3); after the statistical analysis it was found that the observation values of quartile 1and quartile 3 lies between 22.68 HU and 26.68 HU.ln grade 3 patients 5.15 HU was the median value and first quartile value was -5.155HU and quartile 3 was 7.94HU. After measuring the difference between HU of spleen and liver in grade one the median value was 12.6HU; 25% of observation have value less than 7.79HU and 75%of observation have value less than 15.26HU.ln grade 2 patients there was more difference ofliver and spleen HU and the study stated that 22.54 HU was the median value; quartile 1and quartile 3 lies between 21.26 HU and 27.04 Honsfield unit. In grade 3 patients there was higher difference ofliverand spleen HU and the median value was -40.83 HU, first quartile value was 38.24 HU and quartile 3 was 50.96 HU. The ROC analysis showed 25 was the cut off value with 0.97 sensitivity and 0.87 specificity. So with the above value of 25 HU, the vessel visualization is not possible. Conclusion:Ultrasound was the first imaging technique for hepatic steatosis. However till date only maximum HU value was given to say the presence or absence of fatty liver. This is the first study.

Item Type: Article
Uncontrolled Keywords: Hounsfield unit; fatty infiltration of liver; ultrasound.
Subjects: Allied Health > MCOAHS Manipal > Medical Imaging Tech
Medicine > KMC Manipal > Radiology
Depositing User: KMC Manipal
Date Deposited: 21 Jul 2015 05:03
Last Modified: 21 Jul 2015 05:03
URI: http://eprints.manipal.edu/id/eprint/143410

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