The potential role of modern US in the follow-up of patients with retroperitoneal fibrosis

Abstract

Purpose: We aimed to evaluate a standardized ultrasonography (US) algorithm for the visualization of pathologic para-aortic tissue in retroperitoneal fibrosis (RPF).

Materials and methods: Thirty-five patients with lumbar RPF of typical extent, as determined by abdominal magnetic resonance imaging, were included. Examinations were conducted using standardized abdominal US with axial sections obtained at the levels of the renal arteries, aortic bifurcation, and both common iliac arteries. Imaging of each section was acquired with fundamental B-mode (US) and tissue harmonic imaging, respectively. In addition, we examined RPF visualized using extended field-of-view US.

Results: Tissue harmonic imaging adequately visualized RPF of typical extent in 33 patients (94.2%). Excellent and good visualization with mild artifacts were achieved in 25 (71.4%) and six (17.1%) patients, respectively. When RPF spread along the iliac arteries, excellent visualization was achieved in 38.7% for the left side and 34.5% for the right side. There were significantly fewer diagnostic examinations for the right iliac (27.6%) than for the left one (9.7%) (P = 0.016). Overall, harmonic imaging achieved significantly better visualization than fundamental B-Mode (P < 0.001).

Conclusion: We described the first systematic evaluation of RPF visualization by modern US techniques. The best imaging quality was found in the typical RPF location, at the level of the aortic bifurcation. These results advocate for the presented US algorithm as an efficient follow-up alternative to cross-sectional imaging in RPF patients.

Figure 1. a–c.

Typical extent of the retroperitoneal fibrosis surrounding the infrarenal aorta (a). Spreading of the fibrosis to the renal arteries and along the common iliac arteries (b). Standardized US examination with four transverse sections (c). AO, aorta; AIC, common iliac artery; RA, renal artery; RPF, retroperitoneal fibrosis.

Figure 2. a–d.

US sections with excellent visualization and corresponding MR images (T1-weighted with fat suppression) in a case with classical para-aortic retroperitoneal fibrosis location at the level of the renal arteries (a), the bifurcation (b), and both iliac arteries (c, d). No para-aortal fibrosis was found at the level of the renal arteries (a).

Figure 3. a–d.

Retroperitoneal fibrosis visualization at the level of aortic bifurcation in excellent (a), good (b), poor (c), and not diagnostic (d) quality.

Figure 4. a–c.

Retroperitoneal fibrosis visualization with extended field-of-view US. The arrows indicate the ventral border of the retroperitoneal fibrosis tissue. Continuous visualization with panorama image generation in the cranio-caudal direction (a). Discontinuous retroperitoneal fibrosis visualization in the cranio-caudal direction (b). Discontinuous retroperitoneal fibrosis visualization with panorama image generation in the caudo-cranial direction (c).