Evaluation of Imaging-Guided Peritoneal Biopsy in Diagnosis of Ascites of Undetermined Origin
Authors: El-Naggar Mohammed Khairy Mostafa , Tantawy Waheed Hussein , Abdelkader Nadia Abdelaaty , Ibrahim Eman Abdel-Salam , Marzouk Mohammed Abo Zaid 
Published: October 2021

Abstract

Background
Regarding ascites of unknown origin, diagnostic laparoscopy is an invasive procedure, there are certain complications reported with this procedure i.e. haemorrhage, infection and air embolism. Ultrasound-guided percutaneous biopsies are easy to perform in an outpatient clinic. This procedure is safe, has a low incidence of injury and does not cause serious complications. Computed tomography (CT)-guided percutaneous biopsy is not a real-time operation, and it involves quite a few complicated procedures.

Aim
To evaluate the role of imaging guided peritoneal biopsy in diagnosis of ascites of undetermined origin (ascites of local cause). 2ry aim was to present the role of imaging-guided biopsy of the omentum or other extravisceral masses as a minimally invasive procedure compared to laparoscopy in the diagnosis of these difficult-to-diagnose group of patients.

Patients and methods
Patients with clinically suspected and radiologically confirmed ascites of unknown etiology represented the population of our study. These patients were referred to the ascites study group (ASG) and admitted to Tropical Medicine Department, Ain Shams University Hospitals in the period from June 2017 to November 2019. The study was conducted on 63 patients with ascites of unknown etiology fulfilling the inclusion criteria. They underwent ultrasound-guided cytology/biopsy of peritoneum, omentum or extravisceral masses. CT guided percutaneous peritoneal biopsy was done in cases of failure of ultrasound guided technique. Laparoscopy was needed when the imaging-guided biopsy was not diagnostic.

Results
54 patients (85.7%) underwent US guided biopsies, 48 patients of them (76.2%) were successfully diagnosed, while the other six patients (9.5%) were sent for laparoscopy after nonconclusive histopathological examination of the biopsies taken US guided. The patients underwent laparoscopy were successfully diagnosed except for one patient who died intraoperatively. The other nine patients (14.3%) underwent CT guided biopsies (not accessible by US guided modality) and all of them were successfully diagnosed.
Imaging guided biopsies had perfect sensitivity (100%) and NPV (100%) in differentiating neoplastic lesions. We found that imaging-guided procedures had a high diagnostic accuracy of 88.8% & 100% done US & CT guided respectively with a sensitivity of 100%, specificity of 83.3% and NPV of 100%, which could distinguish malignant from benign ascites.
Complications were most frequent in laparocopy, followed by CT guided biopsies and least in US guided biopsies with P-value &lt;0.001.

Conclusion
Percutaneous imaging-guided biopsy (US/CT guided) of the peritoneum, omenta, and mesentery has been established as a safe, well-tolerated procedure with high diagnostic accuracy. It can minimize further unnecessary invasive procedures e.g laparoscopy. It can help in directing the management, shortening the patient’s hospital stay and reducing the costs and complications.