Ultrasound-Guided Omental Biopsy: Diagnostic Yield and Association With CT Features Based on a Single-Institution 18-Year Series

Assessing the risk of unintended intestinal sampling in omental and mesenteric core needle biopsies

OBJECTIVE

Assess the incidence and clinical outcomes of inadvertent bowel sampling with a 17-G coaxial system with an 18-G semi-automatic biopsy needle, omental and mesenteric CT and US-guided biopsy.

METHODS

In this retrospective study, consecutive patients undergoing omental and mesenteric CT and US-guided biopsy with a 17-G introducer, an 18-G semi-automatic biopsy device performed at a single tertiary academic institution between March 1, 2005, and March 1, 2024, were included to assess the incidence and clinical outcomes of inadvertent bowel sampling. Descriptive statistics were used.

RESULTS

Among 265 biopsies, there were six cases (6/265, 2.3%) with inadvertent bowel sampling identified on pathology. The median age was 83.5 years (IQR: 65.6-85.3) in patients with inadvertent bowel sampling, and 66 years (IQR: 58-74) in patients without inadvertent bowel sampling, p = 0.02. In patients with inadvertent bowel sampling, 4/6 (66.7%) of biopsies were from mesentery, in contrast to the patients without inadvertent bowel sampling, with 210/259 (81.1%) omental biopsies, p: 0.04. The bowel mucosa on pathology was arising from the colon in 3/6 (50%), the duodenum in 2/6 (34%), and the distal ileum in 1/6 (17%). All patients underwent a standard post-procedure observation time of 1 hour, during which no signs or symptoms of clinically significant bowel perforations were identified. No patients were admitted after the procedure, and no patients required admission within 30 days after the procedure for bowel-related indications.

CONCLUSION

Inadvertent bowel sampling during percutaneous omental and mesenteric biopsy with a 17 G introducer, and an 18 G semi-automatic needle is a rare, but likely benign event, even in patients without bowel preparation or antibiotic coverage.

KEY POINTS

Question The incidence and clinical consequences of unintended intestinal sampling in percutaneous omental and mesenteric core needle biopsies are unknown. Findings Inadvertent bowel sampling occurred in 2.3% of omental and mesenteric biopsies. No clinically significant complication was observed, despite the lack of bowel preparation or antibiotic prophylaxis. Clinical relevance Inadvertent bowel sampling is rare, more common in elderly patients and mesenteric biopsies, and likely benign, even without preparatory measures. However, given the potential for serious complications reported in the literature, meticulous technique remains crucial to minimizing the risk.

Safety and efficacy evaluation of contrast-enhanced ultrasound-guided omental biopsy: a single-center prospective study

OBJECTIVES

Contrast-enhanced ultrasound (CEUS) assesses omental lesion nature, but CEUS-guided biopsy feasibility, effectiveness, and safety are uncertain.

METHODS

From January 2020 to January 2024, patients scheduled for ultrasound-guided omental biopsy at the First Hospital of China Medical University were enrolled. They were divided into CEUS-guided and conventional ultrasound-guided groups, balanced using propensity score matching (PSM). Success rate, diagnostic accuracy, and complication rate were compared. Subgroup analyses considered sonographic features, with significance at p < 0.05.

RESULTS

After PSM, 310 CEUS-guided and 160 conventional ultrasound-guided patients were analyzed. Groups were similar in demographics and omental characteristics (p > 0.05). CEUS-guided biopsy had higher sample acquisition (97.42% vs. 93.13%, p = 0.029) and diagnostic accuracy (96.03% vs. 87.92%, p = 0.002). Overall complication rate was 9.36% (44/470), with distant metastasis in 0.43% (2/470). Complication rates did not differ significantly between groups. In hyperechoic group, dense group, and non-nodule group, CEUS-guided biopsy had higher success (97.99% vs. 92.55%, p = 0.042) and accuracy (96.48% vs. 86.17%, p = 0.002). In non-nodule group, CEUS-guided accuracy was superior (93.41% vs. 84.11%, p = 0.015).

CONCLUSION

Ultrasound-guided omental biopsy is a safe and effective method for obtaining samples. CEUS-guided omental biopsy enhances sample acquisition and diagnostic accuracy, especially in hyperechoic group, dense group, and non-nodule group, suggesting it is a more accurate and effective diagnostic method.

KEY POINTS

Question Selecting a puncture site for diffuse lesions of the greater omentum presents challenges, as conventional ultrasound-guided biopsy often encounters difficulties in avoiding local necrotic tissue. Findings Ultrasound-guided biopsy of the greater omentum is a safe and effective diagnostic method, especially when augmented with CEUS, which can significantly enhance diagnostic accuracy. Clinical relevance CEUS can markedly enhance diagnostic accuracy by providing a robust foundation for selecting the biopsy site and pathway. Therefore, it is advisable to routinely employ CEUS-guided puncture pathways for atypical omental lesions.

Innovative optimization of greater omentum imaging report and data system for enhanced risk stratification of omental lesions

BACKGROUND

In 2020, we introduced the Greater Omentum Imaging-Reporting and Data System (GOI-RADS), a novel classification system related to peritoneal lesions. However, its clinical application remained unvalidated.

OBJECTIVE

This study aimed to validate GOI-RADS, optimize its parameters for a new grading system, and explore its clinical usefulness.

METHODS

A retrospective-prospective study was conducted to validate and refine the GOI-RADS system. The study consisted of two phases: a retrospective validation phase and a prospective application phase. The first phase included patients with peritoneal lesions from 2019 to 2021, classified by GOI-RADS and verified against pathology. Contrast-enhanced ultrasound (CEUS) and real-time elastography (RTE) data were collected for developing a new grading system. Odds ratios optimized parameters. The second phase (2021-2024) assessed diagnostic consistency among sonographers and performance of grading systems.

RESULTS

Among 215 patients with peritoneal lesions, the actual malignancy rates for GOI-RADS 2 (40.00%) and GOI-RADS 3 (61.22%) were much higher than predicted (5.56% and 37.25%). Combining CEUS and RTE parameters showed varying sensitivity and specificity: RTE + GOI-RADS (95.35%, 55.56%) and CEUS + GOI-RADS (96.51%, 44.44%). However, the grading system based on multiple ultrasound parameters, specifically when incorporating RTE, CEUS parameters, and GOI-RADS (Multi-GOIRADS), exhibited the highest diagnostic sensitivity and specificity of 88.37% and 83.33%, respectively. Its simplified version, sMulti-GOIRADS, had sensitivity of 73.26% and specificity of 94.44%. In the prospective study involving three sonographers of different qualifications, the use of sMulti-GOIRADS was found to be the most time-efficient and showed excellent diagnostic consistency among them. In contrast, Multi-GOIRADS required more time for scoring but offered superior diagnostic performance, particularly among senior sonographers (88.35% and 91.43%).

CONCLUSIONS

This study proposes a multiparametric ultrasound-based imaging-reporting and data system for risk stratification of omental malignancy, Multi-GOIRADS, and presents an optimized and simplified version, sMulti-GOIRADS, which demonstrates excellent diagnostic consistency and performance in clinical applications.

Primary Omental Leiomyosarcoma With Pulmonary Metastases: A Case Report of Surgical Management and Chemotherapy Response

Primary omental leiomyosarcoma is an extraordinarily rare tumor, with only a limited number of cases reported in the medical literature. Early surgical intervention appears to be a key determinant in the successful treatment of this malignancy, although more cases are needed to establish a standardized approach for optimal management. Leiomyosarcomas originating from the omentum present unique diagnostic challenges due to their rarity and often nonspecific clinical and radiologic findings. The complexities of diagnosing and managing this condition are compounded in rural areas where access to advanced diagnostic tools and specialists is limited. Leiomyosarcomas appear on abdominal computerized tomography (CT) as heterogeneous solid masses with cystic areas that enhance with contrast. While imaging can suggest the diagnosis, histopathology is required for confirmation. These tumors are highly aggressive, and complete surgical resection is the only definitive treatment, with resectability depending on peritoneal implants or metastasis. Other treatments, such as chemotherapy, radiation, and embolization, have variable success. Liver metastasis is the most common and a poor prognostic factor. Despite alternative therapies, surgery remains the best option for long-term survival. This case not only highlights the rarity and diagnostic challenges of omental leiomyosarcoma but also underscores the importance of timely referral to specialized centers. It further emphasizes the need for comprehensive diagnostic evaluations and personalized treatment plans tailored to the unique characteristics of each patient. Addressing these challenges through early intervention and targeted therapies is crucial to improving outcomes for patients with rare malignancies like omental leiomyosarcoma.

Factors influencing diagnostic yield in ultrasound-guided omental biopsies: insights from a retrospective study

PURPOSE

To evaluate the safety, diagnostic accuracy, and factors influencing the diagnostic yield of ultrasound (US)-guided omental biopsies.

MATERIALS AND METHODS

This retrospective study included 109 patients who underwent US-guided omental biopsies between June 2020 and June 2024. Pre-biopsy diagnostic images (CT, MRI, or [18 F]FDG PET/CT) were reviewed. Diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and adverse events were evaluated. Surgical or clinical diagnoses with follow-up served as the diagnostic reference standard. Associations between diagnostic yield and findings on pre-biopsy imaging and biopsy US were explored.

RESULTS

The study achieved a technical success rate of 100%. Initial biopsy results showed a sensitivity of 82.6%, specificity of 100%, PPV of 100%, NPV of 60.5%, and diagnostic accuracy of 86.2%. The pre-biopsy imaging modality was not related to diagnostic accuracy. Ascites interposition on the puncture route was significantly higher in patients without diagnostic accuracy (73.3% vs. 30.9%, p = 0.002). Deeper lesions exhibited lower diagnostic accuracy (p = 0.003). No major or minor complications were associated with the biopsies.

CONCLUSION

Percutaneous omental biopsy is an effective and safe method for evaluating omental abnormalities. Depth from the needle entry site and the presence of ascites along the puncture route were identified as factors affecting diagnostic accuracy. The choice of imaging modality did not impact diagnostic outcomes, highlighting the importance of lesion-specific factors in the planning of biopsies.

A Curious Case of Omental Oxalate Crystals in a Patient With Struma Ovarii: Pointers to an Unusual Clinicopathological Scenario

Percutaneous image-guided biopsies are becoming increasingly common in routine pathology practice, with the greater omentum emerging as a common target. We present herein an account of a middle-aged lady with a complex ovarian mass, omental thickening, and raised serum CA125; clinically suspected to have advanced ovarian malignancy. Fine needle aspiration cytology (FNAC) from the ovarian mass was inconclusive. Omental biopsy revealed only refractile, birefringent crystalline material with surrounding foreign body giant cell reaction; thus surprising the clinical team. Subsequent resection of the ovarian mass showed a teratoma composed exclusively of thyroid tissue, diagnosed as struma ovarii. The omental crystals, interpreted as calcium oxalate crystals, were possibly a consequence of colloid seeding during the ovarian mass FNAC.

Ultrasound-guided biopsy of challenging abdominopelvic targets

Percutaneous ultrasound-guided biopsies have become the standard of practice for tissue diagnosis in the abdomen and pelvis for many sites including liver, kidney, abdominal wall, and peripheral nodal stations. Additional targets may appear difficult or impossible to safely biopsy by ultrasound due to interposed bowel loops/vasculature, deep positioning, association with the bowel, or concern for poor visibility; however, by optimizing technique, it is often possible to safely and efficiently use real-time ultrasound guidance for sampling targets that normally would be considered only appropriate for CT guided or surgical/endoscopic biopsy.

ARFI elastography of the omentum: feasibility and diagnostic performance in differentiating benign from malignant omental masses

OBJECTIVE

To evaluate the feasibility and diagnostic performance of acoustic radiation force impulse (ARFI) elastography in different omental masses (OM).

DESIGN

This was a retrospective analysis of 106 patients with OM defined as omental thickness ≥1 cm, who underwent abdominal B-mode ultrasound (US) and standardised ARFI examinations of the OM between September 2018 and June 2021 at our university hospital. A cytohistological confirmation was available in 91/106 (85.8%) of all OM, including all 65/65 (100%) malignant OM (mOM) and 26/41 (63.4%) of benign OM (bOM). In 15/41 (36.6%) of bOM; cross-sectional imaging and or US follow-up with a mean duration of 19.8±3.1 months was performed. To examine the mean ARFI velocities (MAV) for potential cut-off values between bOM and mOM a receiver operating characteristic analysis was implemented.

RESULTS

The MAV in the mOM group (2.71±1.04 m/s) was significantly higher than that of bOM group (1.27±0.87 m/s) (p<0.001). Using 1.97 m/s as a cut-off yielded a sensitivity and specificity of 76.9% and 85.4%, respectively, in diagnosing mOM (area under the curve=0.851, 95% CI=0.774 to 0.928).

CONCLUSION

ARFI elastography is feasible in the omentum and may represent a good non-invasive additional tool in differentiating bOM from mOM.