Value of multi-modal ultrasound in evaluation of the accessory renal artery

Abstract

Background: The evaluation of the accessory renal artery (ARA) holds clinical significance in the effective intervention of resistant hypertension and renal vascular-related surgical procedures. Multi-modal ultrasound is a non-invasive, secure, and real-time imaging modality, especially useful in patients with renal impairment. Nevertheless, few studies have focused on the value of multi-modal ultrasound in the assessment of the ARA. This study aimed to explore the diagnostic performances of multi-modal ultrasound in the assessment of the ARA.

Methods: A retrospective data collection (clinical and imaging information) was conducted on patients who underwent renal artery conventional ultrasound and contrast-enhanced ultrasound (CEUS) examinations between August 2019 and November 2023 in Beijing Hospital. A total of 73 patients with a unilateral or bilateral ARA based on their computed tomography angiography (CTA) results were included. Compared with CTA results, the accuracy of multi-modal ultrasound for the assessment of the ARA was evaluated, and underlying reasons for misdiagnosis and missed diagnosis were analyzed.

Results: Among the 73 patients (144 kidneys), CTA identified 85 ARAs, whereas multi-modal ultrasound detected 70 ARAs. Although multi-modal ultrasound failed to detect 15 ARAs, it did not result in any false-positive diagnoses. When CTA did not detect any ARAs in a kidney, multi-modal ultrasound also did not find any ARA. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of multi-modal ultrasound in diagnosing ARA were calculated as 82.4%, 100%, 100%, 81.0%, and 90.9%, respectively. The receiver operating characteristic (ROC) analysis demonstrated an area under the curve (AUC) of 0.906 (P<0.001). The consistency analysis yielded a kappa value of 0.806 (P<0.01). Comparisons were conducted between patients with detected ARAs and those with missed ARAs. The age and body mass index (BMI) between the two groups were found to be statistically significant (P<0.05).

Conclusions: Multi-modal ultrasound, characterized by its non-invasive, safe, and reproducible nature, demonstrates a high level of diagnostic accuracy in detecting the ARA. Thus, multi-modal ultrasound holds promise as a valuable tool for evaluating the ARA.

Keywords: Accessory renal artery (ARA); evaluation; multi-modal ultrasound; value.

Figure 1

Flowchart of study patient selection. ARA, accessory renal artery; CEUS, contrast-enhanced ultrasound; CTA, computed tomography angiography.

Figure 2

A representative example for the ARA multi-modal ultrasound examinations. The patient was placed in a right lateral decubitus position, and the five steps for the ARA multi-modal ultrasound imaging were outlined as follows: (A) initial evaluation of the two renal arteries originating from the abdominal aorta using two-dimensional grayscale ultrasound mode, (B) visualization of blood flow in the two renal arteries using color Doppler flow in CDFI mode, (C,D) measurement of hemodynamic parameters in the main and accessory renal artery using pulsed wave Doppler mode respectively, (E,F) dynamic and clear display of the entire course of the two renal arteries from the abdominal aorta to the kidneys in CEUS mode. ARA, accessory renal artery; CDFI, color Doppler flow imaging; CEUS, contrast-enhanced ultrasound.

Figure 3

The ROC curve for multi-modal ultrasound. The red line represents multi-modal ultrasound; the yellow line represents the reference line. AUC, area under the curve; ROC, receiver operating characteristic.