Presented by: Jeremy Bolton Medical Student
Monash University

Introduction

Endoluminal ultrasound is widely deployed in respiratory and gastrointestinal diseases and during intravascular cases. Transducers, on 6-9Fr catheters, are available however, the use of ELUS in upper tract diseases is currently low. Locating sub-mucosal stones intra-operatively, staging upper tract urothelial carcinoma and avoiding crossing vessels at endopyelotomy are important and ongoing issues that urologists face that may benefit from endoluminal imaging. 

Materials

A literature review was performed to assess the efficacy of ELUS in the following ureteric diseases; urolithiasis, upper tract urothelial carcinoma, stricture disease and pelvico-ureteric junction obstruction (PUJO). 

Results

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Endoluminal ultrasound has proven to be useful at the time of endopyelotomy for PUJO as it can identify crossing vessels, some not detectable on CT angiography, and allow the urologist to avoid these when making their incision. In one study 16 out of 37 patients had the endopyelotomy location changed due to ELUS findings and no bleeding events occurred. The endopyelotomy success rate was 87.5%. 

Ureteric ELUS may be utilised for submucosal ureteric stones as they are highly visible. Endoluminal ultrasound may be deployed in the case of known sub-mucosal urolithiasis when the ureter appears stone-free. It may help identify sub-mucosal stones, or stones within diverticulum. 

Ureteric ELUS provides 360° imaging which has been demonstrated to assess ureteric stricture length, degree of fibrosis and aetiology. Endoluminal ultrasound has been reported to identify retroperitoneal fibrosis, endometrioma, submucosal stones, urinomas and cancers. 

Endoluminal ultrasound has been analysed for its use in determining muscle invasive urothelial carcinoma of the ureter. The PPV for >/= pT2 was only 16.7% in one study of six patients with MIBC and 76.2% in 21 patients with <pT2 disease. 

Conclusion

Ureteric ELUS has been reported to be a useful tool in endopyelotomy, urolithiasis and stricture disease. The staging of ureteric urothelial carcinoma remains unsatisfactory with current imaging techniques and biopsy methods and, based on the current literature, ELUS does not appear to have a strong enough PPV to determine muscle invasion however larger studies are required. 

Funding

None

Lead Authors

Jake Tempo, BMBS
Austin Health

Co-Authors

Jeremy Bolton,
Monash University

Joseph Ischia, PhD
Austin Health

Damien Bolton, PhD
Austin Health

Sam Sii, MBBS
Austin Health