Peritoneal-scrotal dialysate leakage demonstrated on SPECT/CT imaging in a patient on peritoneal dialysis.

A 62-year-old male with end-stage renal failure on peritoneal dialysis presented with sudden onset scrotal swelling following a violent coughing fit. He was referred for a peritoneal leak study to evaluate the scrotal swelling. This case illustrates the benefit of SPECT/CT imaging in the diagnosis and anatomic localization of peritoneal leakage as a complication of peritoneal dialysis.

Introduction

Continuous ambulatory peritoneal dialysis (CAPD) is a widely used treatment option for patients with end stage renal disease. First pioneered in 1976, this treatment technique remains widely used in modern medicine [1,2]. CAPD may lead to numerous complications, both of infectious and noninfectious causes. Dialysate leakage is a one of the noninfectious complications, arising due to an increased intraabdominal pressure associated with dialysate infusion [1]. Multiple modalities can be used to diagnose dialysate leakage. The following case report describes the diagnostic utility of SPECT/CT, a fusion imaging technique involving single-photon emission computed tomography and low-dose noncontrast computed tomography.

Case presentation

A 62-year-old man with end-stage renal disease receiving continuous ambulatory peritoneal dialysis presented with a sudden onset of scrotal swelling following a violent coughing fit.

Examination technique

Following intraperitoneal injection of 99mTc-MAA via the previously inserted Tenckhoff catheter, planar images were obtained by a gamma camera after 1 hour and 5 hours (Fig. 1). At 5 hours postinjection of 99mTc-MAA, SPECT/CT images were also obtained (Figs. 2 and 3).

Fig. 1

Planar images after 1 hour (A, anterior), 3 hours (B, posterior), and 5 hours (C, anterior; D, posterior). The distribution of MAA can be seen to collect within the dependent portions of the peritoneal cavity in the first 3 hours (A, B) before the peritoneo-scrotal leakage is demonstrated by the radionuclide uptake at the right inguinal canal region leading into the scrotal sac at the 5th hour (C, D).

Fig. 2

At 5 hours postinjection of 99mTc-MAA, further evaluation with low-dose CT with axial (A), coronal (B), and sagittal views (C), corresponding SPECT (D-F) and fusion SPECT/CT imaging (G-I) localized the uptake (arrows) at the right inguinal canal, consistent with a patent processus vaginalis. The axial fusion image (G) clearly demonstrates the uptake at the superficial inguinal ring, an extraperitoneal structure. The coronal (H) and sagittal (I) fusion images further illustrates the communication between the peritoneum and the right inguinal canal.

Fig. 3

Low-dose CT with axial (A), coronal (B), and sagittal views (C), corresponding SPECT (D-F) and fusion SPECT/CT imaging (G-I) are again depicted similar to Figure 2, but with the axial view (G) taken more inferiorly at the level of the scrotum, and the coronal view (H) taken more anteriorly. The sagittal view (I) is taken more laterally towards the left. The axial fusion view (G) displays mild heterogeneous 99mTc-MAA uptake in the right hemiscrotum, while the left hemiscrotum has minimal radionuclide activity on the left sagittal view (I). The tracer uptake in the coronal section (H) clearly highlights a communication between the peritoneal cavity and the scrotum via the right inguinal canal, in keeping with a peritoneo-scrotal leakage.

Findings

On the planar images, the distribution of MAA can be seen to collect within the dependent portions of the peritoneal cavity in the first 3 hours (A, B) before the peritoneo-scrotal leakage is demonstrated by the radionuclide uptake at the right inguinal canal region leading into the scrotal sac at the 5th hour. On the fusion images, the uptake was precisely localized to the right superficial inguinal ring.

Conclusion

This SPECT/CT study demonstrated a patent peritoneo-scrotal communication using 99mTc-MAA as the radionuclide, confirming a dialysate leakage as the cause of the scrotal swelling.

Discussion

Peritoneal leakage is a common complication affecting more than 5% of patients receiving continuous ambulatory peritoneal dialysis [3]. Dialysate leakage can occur at the catheter exit site, pleural cavity via diaphragmatic defects, abdominal hernias, and a patent processus vaginalis as in this case [3]. Different imaging modalities have been utilized to diagnose peritoneal leakage, including intraperitoneal methylene blue instillation, contrast catheterogram and peritoneography, contrast CT, and abdomino-pelvic scintigraphy [4,5]. Chemical and contrast material are associated with allergic reactions and peritonitis [4]. Additionally, intravenous contrast is a well-described nephrotoxin causing acute kidney injury [6]. Scintigraphy is a safe and highly sensitive modality with minimal radiation exposure, allergic reactions and peritonitis risk [4,5]. Various radiopharmaceuticals have been used in scintigraphy and SPECT/CT imaging for dialysate leakage detection, including 99mTc sulfur colloid, 99mTc-pertechnetate, 99mTc phytate and 99mTc-MAA and 99mTc-DTPA [4,[7], [8], [9], [10].

Conclusion

This case illustrates the safety and utility of SPECT/CT with 99mTc-MAA in precisely localizing peritoneo-scrotal dialysate leakage as a complication of peritoneal dialysis.

Patient consent

Written informed consent has been obtained from the patient for the publication of this case report and its associated images.