Evaluating anemia using contrast-enhanced spectral detector CT of the chest in a large cohort of 522 patients

Abstract

Objectives The blood of patients with anemia demonstrates distinctly lower attenuation in unenhanced CT images. However, the frequent usage of intravenous contrast hampers evaluation of anemia. Spectral detector computed tomography (SDCT) allows for reconstruction of virtual non-contrast images (VNC) from contrast-enhanced data (CE). The purpose of this study was to evaluate whether VNC allow for prediction of anemia. Methods Five hundred twenty-two patients with CE-SDCT of the chest and accessible serum hemoglobin (HbS) were retrospectively included. Patients were assigned to three groups (severe anemia, moderate/mild anemia, and healthy) based on recent lab tests (≤ 7 days) for HbS following gender and the WHO definition of anemia. CT attenuation was determined using two ROI in the left ventricular lumen and one ROI in the descending thoracic aorta. ROI were placed on CE and copied to VNC. ANOVA, linear regression, and receiver operating characteristics were used for statistic evaluation. Results Average HbS was 11.6 ± 2.4 g/dl. Attenuation on VNC showed significant differences between healthy patients, patients with mild/moderate anemia, and severely anemic patients (all p ≤ 0.05). Applying cutoffs of 39.2/37.6 HU and 33.6/32.7 HU allowed to differentiate between healthy, mild/moderately, and severely anemic men/women (AUC 0.857/0.833 and 0.879/0.932). A linear relationship between HbS and attenuation on VNC was established (r2 = 0.54, HbS = − 0.875 + 0.329 × HU). Conclusions An approximation of HbS and presence of anemia can be conducted based on simple attenuation measurements in contrast-enhanced SDCT examinations enabled by VNC imaging. Key Points • While the attenuation of blood is a previously described biomarker for anemia in non-contrast images, virtual non-contrast images from spectral detector CT circumvent this limitation and allow for diagnosis of anemia in contrast-enhanced scans. • Attenuation of blood in virtual non-contrast images derived from spectral detector CT shows a moderate correlation to serum hemoglobin levels. • Presence of anemia be estimated in virtual non-contrast images using proposed cutoffs of 39.2 HU and 37.6 HU for men and women, respectively, to differentiate between healthy and anemic patients.

Prediction of anemia on enhanced computed tomography of the thorax using virtual non-contrast reconstructions

“…[ 20 ] Our study showed also a similar results to this work, both in regards to the correlation between hemoglobin levels and CT attenuation of the blood, and the threshold for defining anemia (r = 0.54; HU values of 39.2 and 37.6 for men and women, respectively). [ 20 ]…”

Magnitudes of Anemia and Its Determinant Factors Among Lactating Mothers in East African Countries: Using the Generalized Mixed-Effect Model

“…Anemia is a disorder defined as a reduced absolute number of circulating red blood cells, indicated by a low serum hemoglobin concentration ( 1 ). It occurs when a low number of red blood cells in the circulatory system leaves the oxygen-carrying capacity insufficient to meet physiological needs ( 2 ).…”

“…Iron deficiency is the most significant contributor to the occurrence of anemia, which accounts for 50% of the cases. Whereas vitamin deficiencies (folate and vitamin B12), infections, and hemoglobinopathies contribute to the rest of the cases of anemia worldwide ( 1 – 3 , 5 , 6 ). Lactating women, women of reproductive age, adolescent girls, pregnant women, newborn infants, and young children are the major risk groups for anemia ( 3 , 12 ).…”

Comparison between thoracic low-dose computed tomography and conventional-dose computed tomography in evaluating anemia: A preliminary study in a Chinese screening cohort

“…Zhou et al ( 27 ) considered the threshold of IVS-LV at 13.5 HU could obtain high diagnostic performance for severe anemia with the AUCs of 0.908 for men and 0.923 for women, respectively. Zopfs et al ( 29 ) demonstrated that an approximation of serum Hb level and anemia can be conducted based on measurements of the LV and DAo in reconstructive virtual non-contrast (VNC) images. Cutoff values of mild, moderate, and severe anemia in VNC images are 39.2 HU (AUC = 0.857) and 33.6 HU (AUC = 0.879) for men and 37.6 HU (AUC = 0.833) and 32.7 HU (AUC = 0.932) for women, respectively.…”