Role of Digital Image Analysis in Diagnosing Nature of Indeterminate Biliary Duct Stricture

Biliary strictures (BSs) are common in clinical practice, but differentiating nature of the stricture either benign or malignant remains a challenge. Although there is a great advance in imaging and laboratory investigations, nature of BS is still unclear in some patients. Therefore, preoperative evaluation of such strictures is mandatory to put suitable plan with appropriate management.

BS is considered indeterminate biliary duct stricture (IBDS) if it has the following conditions; 1) no obvious mass on abdominal ultrasound (US), or magnetic resonance cholangiopancreatography (MRCP); 2) no distant metastasis on abdominal US, or MRI; and 3) no recent history of hepatobiliary surgery in the last 3 months.

IBDS has a particularly complex challenge, because patients and their physicians must weigh the malignant potential against benign etiologies in the face of morbidity of surgical intervention. About 15-24% of the patients had surgical intervention for suspected IBDS have a benign aetiology. Therefore, preoperative evaluation of such strictures is mandatory to put suitable plan with appropriate management.

Conventional cytological evaluation (CCE) has become the standard modality of practice for the investigation of such stricture. CCE had low diagnostic yield with an overall sensitivity of 41.6% and a negative predictive value of 58%. This low diagnostic yield is mainly attributed to desmoplastic reaction in BS.

Radiological elevation of BS with different modalities as MRCP enables us to detect the stricture and its extent and exclude other causes of obstruction. These modalities fail to determine nature of BS in many cases. In addition to, inability to take tissue sampling or perform therapeutic intervention.