Hemoglobin Estimation using Hounsfield Unit Measurements on the Single Nonenhanced Computed Tomography Abdomen Scan and Its Correlation with Biochemically derived Hemoglobin
Padma V Badhe, KN Puneeth Kumar, Kartik Mittal, Priya Hira, Sagar Sonone
AIM: â€¢ To find the correlation of Hounsfield unit (HU) values with biochemically derived values of hemoglobin (Hb). â€¢ To postulate new radiological formula for the estimation of Hb. â€¢ To evaluate interventricular septum (IVS) and its attenuation difference with the ventricle for diagnosis of anemia. â€¢ Accurate Hb estimation in emergency set-up (including trauma) for patient requiring computed tomography (CT) scan. MATERIALS AND METHODS: A total of 200 random adult patients who had undergone CT abdomen-chest were enrolled in the study: 52% males, mean age 30 Â± 15 SD, and 48% females, mean age 30 Â± 14 SD. The two groups were then subdivided into anemic and normal subjects, 10 gm/dL being taken as the borderline values for males and females. Blood density (HU) was measured after defining three regions of interest (ROI) on the aorta, inferior vena cava (IVC), and left ventricle (LV). Visualization/nonvisualization of the IVS distinct from blood density of LV was also assessed. RESULTS: Correlation between HU and Hb concentration was seen in vivo (r = 0.73, p < 0.001). When the mean density value was 42 HU in our sample, the expected Hb value was 12.6 gm/ dL (Â± 1.5 SD). A significant difference of blood attenuation values was present between normal subjects and anemic patients (p < 0.001). This difference identifies the cut-off density value, below which the patient is sure to be anemic: the value is different for males and females (33 HU for females and 36 HU for males). â€¢ A formula for Hb estimation by using HU values has been figured out. â€¢ Visualization of the IVS in non-enhanced computed tomography is an indirect marker of anemia (99% confidence). â€¢ Hb estimation by CT before biochemical reports arrived proved beneficial to the patient in acute trauma setting. DISCUSSION AND CONCLUSION: It is an observational study in which a new formula for estimation of Hb can be given radiologically and in emergency set-up (including trauma), and CT scan may guide an accurate value of Hb estimation before biochemical results are revealed.
Hemoglobin, Hounsfield unit, Non-enhanced