Abdominal ultrasound with scintigraphic and clinical correlates in infants with sickle cell anemia: baseline data from the BABY HUG trial

Abstract

Objective: The purpose of this study is to perform and evaluate baseline abdominal ultrasound in infants with sickle cell anemia who participated in the BABY HUG multiinstitutional randomized placebo-controlled trial of hydroxyurea therapy and to examine the potential relationships among ultrasound results and clinical, nuclear medicine, and laboratory data.

Subjects and methods: After local institutional review board approval and with informed guardian consent, 116 girls and 87 boys (age range, 7.5-18 months) with sickle cell anemia underwent standardized abdominal sonography at 14 institutions. Imaging was centrally reviewed by one radiologist who assessed and measured the spleen, kidneys, gallbladder, and common bile duct. Baseline physical assessment of spleen size, serum alanine aminotransferase and bilirubin levels, (99m)Tc sulfur colloid liver-spleen scans, and (99m)Tc diethylenetriaminepentaacetic acid clearance glomerular filtration rates (GFRs) were obtained. Analysis of variance and the Student test were performed to compare sonographic findings to published results in healthy children and to clinical and laboratory findings.

Results: The mean (± SD) spleen volume (108 ± 47 mL) was significantly greater than published normal control values (30 ± 14 mL; p < 0.0001). There was no correlation between spleen volume and function assessed by liver-spleen scan. The mean GFR (125 ± 34 mL/min/1.73 m(2)) was elevated compared with control GFRs (92 ± 18 mL/min/1.73 m(2)). Renal volumes (right kidney, 29 ± 8 mL; left kidney, 31 ± 9 mL) were significantly greater than control volumes (right kidney, 27 ± 3 mL; left kidney, 27 ± 3 mL; p < 0.0001) and were positively correlated with GFR (p = 0.0009). Five percent of patients had sonographic biliary abnormalities (sludge, n = 6; dilated common bile duct, n = 2; and cholelithiasis and thickened gallbladder wall, n = 1 each). There was no correlation between biliary sonographic findings and laboratory results.

Conclusion: In infants with sickle cell anemia, sonographic spleen volume does not reflect function, but increased renal volume correlates with GFR and is consistent with hyperfiltration. Sonographic biliary abnormalities can occur early in life, while remaining clinically silent.

Trial registration: ClinicalTrials.gov NCT00006400.

Figures

Fig. 1. Spleen measurement technique

A, Image shows placement of cursors for longitudinal (X) and anteroposterior (+) diameter measurements. B, Image shows placement of cursors for transverse (X) and anteroposterior (+) diameter measurements. Sonographic image plane that best depicted anteroposterior margins was used for anteroposterior measurement.

Fig. 2. Kidney measurement technique

A, Image shows placement of cursors for length (X) and anteroposterior (+) diameter measurements. B, Image shows placement of cursors for transverse (X) and anteroposterior (+) diameter measurements. Sonographic image plane that best depicted anteroposterior margins was used for anteroposterior measurement.

Fig. 3

Correlation of spleen volume and 99mTc sulfur-colloid spleen uptake in 199 infants with sickle cell anemia, 7.5–18 months old. “Normal” refers to splenic uptake present and equal to that in liver. “Present but Decreased” refers to splenic uptake present but less than that in liver. “Absent” refers to no splenic uptake.

Fig. 4

Scatterplot shows correlation between average kidney volume and diethylene-triaminepentaacetic acid (DTPA) glomerular filtration rate (GFR) in 174 infants with sickle cell anemia, 7.5–18 months old.