Inferences of SPECT renal dynamic imaging injection quality based on lung and abdominal aorta imaging features

Abstract

Objective: To analyze the characteristics of blood flow perfusion images at different injection levels to establish an evaluation standard for renal dynamic imaging injection quality and reduce misdiagnosis.

Methods: Data from 140 single-photon emission computed tomography renal dynamic imaging, collected in our hospital, were retrospectively analyzed. The scans were divided into four groups according to the injection quality: total leakage of the imaging agent (group A), partial leakage (group B), poor bolus injection quality (group C), and good bolus injection quality (group D). The time of appearance and regression of the pulmonary blood perfusion phase, the peak time in the abdominal aorta, and the ratio between peak count and actual drug injection count were analyzed. The renal dynamic imaging was repeated in low-quality examinations, and the comparison between the two exams provided the misdiagnosis rate caused by inadequate injections.

Results: The images of the lungs and abdominal aorta in group A were blurred and indistinguishable; thus, these exams were unreliable. Both appearance and fading time of the bilateral lung shadows were significantly different between groups B, C, and D (p = 0.002 and p = 0.003, respectively). The peak time and peak counting ratio in the abdominal aorta were also significantly different between these groups (p = 0.002 and p < 0.001, respectively). The misdiagnosis rates of renal dynamic imaging in groups A, B, and C due to the different injection levels were significantly different at 94.29%, 77.14%, and 18.29%, respectively.

Conclusions: The times of appearance and regression of the lung shadows and the peak time and peak count ratio in the abdominal aorta in the dynamic renal imaging perfusion phase can help assess the imaging agent injection quality and identify the need for a repeated examination. Improving the imaging agent injection quality can effectively reduce the renal function misdiagnosis rate.

Keywords: Blood flow; Bolus injection; Injection quality; Renal dynamic imaging; SPECT.