NON-INVASIVE IMAGING OF CHOLANGIO-PANCREATIC DISEASES USING MAGNETIC RESONANCE CHOLANGIOPANCREATOGRAPHY AND CORRELATION WITH ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY

Abstract

INTRODUCTION: Biliary & pancreatic pathologies are a wide spectrum of disorders ranging from gall stones to pancreatic carcinoma. Cholangiocarcinoma (CC) is the second commonest primary liver tumour worldwide, after hepatocellular carcinoma (HCC). In suspected biliary obstruction, ultrasonography (US) is reliable for excluding gallstones but is operator-dependent and is insufcient alone for investigating suspected CC. ERCP is needed for assessing the extent of bile duct involvement and respectability. MRCP is better alternative for ERCP as it is non-invasive. Magnetic resonance cholangiopancreatography (MRCP) is an abdominal magnetic resonance (MR) imaging method that allows non-invasive visualization of the pancreato biliary tree and requires no contrast administration. By using heavily T2 weighted sequences, the signal of static or slow-moving uid-lled structures such as the bile and pancreatic ducts is greatly increased, resulting in increased duct-to background contrast. Recent studies have shown that MRCP is comparable with invasive retrograde cholangiopancreatography (ERCP) for diagnosis of extrahepatic bile duct and pancreatic duct abnormalities such as choledocholithiasis, malignant obstruction of the bile and pancreatic ducts, congenital anomalies, and chronic pancreatitis. The use of MRCP in diagnosing biliary obstruction may avoid the use of unnecessary invasive 1 procedures such as ERCP. MRCPhas some advantages over ERCPare non-invasive, cheaper, uses no ionizing radiation, requires no anaesthesia, less operator dependent, better demonstrating ducts proximal to an obstruction or tight stenosis and when combined with conventional T1- and T2- 2-5 weighted sequences, allows anatomic imaging of extra ductal diseases.3 Its diagnostic accuracy has been demonstrated in various studies. AIM/PURPOSE: To estimate the sensitivity, specificity, PPV, NPV in the diagnosis of cholangio-pancreatic diseases by MRCP in comparison to ERCPas gold standard. MATERIALS AND METHODS This was a prospective comparative study conducted in the departments of Radio-diagnosis and Gastroenterology, Apollo hospital, Jubilee hills for a period of 13 months, May 2018- May 2019. Patients with suspected biliary or/and pancreatic pathology referred for MRCP with subsequent assessment by ERCPtaken included in the study. Patients of both genders, all age groups and with suspected cholangiopancreatic disease based on Clinical, Biochemical and USG criteria. In our present study, based on MRCP and ERCP the study population will be classied into 3 groups. Group I (stone disease), group II (stricture), group III (pancreatico biliary tumour).All patients referred to department of radiology Apollo hospital, jubilee hills, Hyderabad was screened and those patients meeting inclusion criteria was informed for the study, an informed consent was obtained and study proforma was completed. MRCP was done using PHILIPS Achieva 1.5 Tesla MRI Machine. MRCP Protocol and MRCP Sequences followed as per standards. All study data from the study proforma sheets was entered into master chart. The sensitivity, specificity, PPV and NPV of each group and their association with benign or malignant was determined by MRCP and compared with that of ERCP finding as gold standard. Data analysis was done using SPSS 23.0 version. RESULTS Out of 76, maximum patients 32 (42.1%) belongs to 41-60 years, 48 (63.2%) were male and 28 (36.8%) were female. Abdominal pain was the most common clinical presentation contributing to 46.1% (35 patients), followed by obstructive jaundice 27 (35.5%), 8 (10.5%) patients were asymptomatic and 6 (7.9%) was on postop follow up. CBD dilatation was seen in 55 patients (72.4%), IHBR dilatation in 40 (52.6%) and 38 (50%) had both. MPD dilatation was present in 16 patients (21%) and both CBD and MPD dilation was seen in 15 (19.7%). MPD dilatation was seen in 16 (21%) of cases and not dilated in 60(89%). The mean CBD diameter in the present study was 9.02 with S.D 3.61and CBD calculus was 8.48 with S.D 3.82 mm. The mean MPD diameter of 76 patients were 3.51 ± 2.18 mm. the MPD diameter ranges from 1.5 to 18 mm. Group 1 (lithiasis): CBD calculus was present in 23 patients (30.3%), 18 (78.3%) were located at distal end, 2 (8.7%) each at proximal and midlevel and 1(4.3%) at the ampulla, GB calculus in 33 patients (43.4%) and both in 12 (15.8%) cases. Among 39 patients ERCP positive for stone, MRCP can accurately detect stones in 86.4% cases and can't able to detect in 13.6% cases. MRCP fails to diagnose one ERCP positive case. There was signicant association found between MRCP and ERCP in detection of stones with p-value < 0.05. Sensitivity, specicity, PPV, NPV and accuracy of MRCP in diagnosing GB and CBD stones when compared to ERCP were 97.4%, 83.8%, 86.4%, 96.8% and 90.8% respectively. Group 2 (strictures): The mean age of patients with stricture was 55.3 ± 16.5 years with age range of 17 -97 yrs. 54.2% of males and 35.7% of female patients had strictures. Among 36 patients ERCP positive for stricture, MRCP can accurately detect strictures in 80.5% cases and can't able to detect in 19.5% cases. MRCP fails to diagnose one ERCP positive case. There was signicant association found between MRCP and ERCP in detection of strictures. Sensitivity, specicity, PPV, NPV and accuracy of MRCP in diagnosing strictures when compared to ERCP were 96.7%, 84.7%, 78.3%, 97.5% and 89.5% respectively. Group 3 (malignancy): Among 16 patients ERCPpositive for malignancy, MRCPaccurately detected malignancies in 87.5% cases and can't able to detect in 19.5% cases. MRCP fails to diagnose 5 ERCP positive case. There was a signicant association found between MRCP and ERCP in detection of malignancies. Sensitivity, specicity, PPV, NPV and accuracy of MRCP in diagnosing malignancy when compared to ERCP were 73.7%, 96.5%, 87.5%, 96.5% and 90.8% respectively. CONCLUSIONS: Sensitivity was high for MRCP in detecting stones 97.4% and strictures 96.7% when compared to malignancies 73.7%. Specicity was high for MRCPin detecting malignancies 96.5% when compared to stones 83.8% and strictures 84.7%. PPVwas high for MRCPin detecting stones 86.4% and malignancies 87.5% when compared to strictures 78.3%.NPV was high for MRCP in detecting stones 96.8% and malignancies 96.5% and strictures 97.5%.7 MRCP can accurately detect 90.8% cases of stones, 89.5% of strictures and 90.8% cases of malignancies. If MRCP is considered the method of choice for evaluating such patients, it can be possible to save time and cost and to avoid complications due to unnecessary procedures.In conclusion, patients with suspicion of biliary or pancreatic disease, but without a clear aetiological factor, should be referred for MRCP after abdominal US and laboratory tests. ERCP can then be reserved for those patients likely to benet from a therapeutic manoeuvre. So, MRCPcan be an alternative to ERCPat least for diagnosis.