Comparative diagnostic evaluation with MR cholangiopancreatography, ultrasonography and CT in patients with pancreatobiliary disease

PURPOSE

The aim of this study was to directly compare the results of magnetic resonance cholangiopancreatography (MRCP) with those of ultrasonography (US) and multislice computed tomography (MSCT) in the diagnosis of pancreaticobiliary diseases.

MATERIALS AND METHODS

A total of 70 patients (41 men, 29 women) aged 22-89 years were studied either before (n=59) or after cholecystectomy (n=11) for biliary lithiasis. Clinical signs and symptoms were jaundice (n=15), abdominal pain (n=37) and proven biliary lithiasis (n=18). MRCP was performed in all patients, whereas abdominal US was performed in 55 (group 1) and MSCT in 37 (group 2) patients. A regional evaluation of the main structures of the pancreaticobiliary system was performed: gallbladder and cystic duct, intra- and extrahepatic bile ducts and main pancreatic duct. Histology (n=27), biopsy (n=5), endoscopic retrograde cholangiopancreatography (ERCP) (n=28) and/or clinical-imaging follow-up (n=10) were considered standards of reference. In particular, patients were classified as showing benign (n=47) or malignant (n=12) lesions or normal biliary anatomy (n=11).

RESULTS

In group 1, the results of MRCP and US were concordant in the majority (92%) of cases; however, statistically significant discordance (p<0.01) was found in the evaluation of the extrahepatic ducts, with nine cases (16%) of middle-distal common bile duct stones being detected on MRCP only. In group 2, the results of MRCP and MSCT were also concordant in most cases (87%). However, findings were significantly discordant when the intra- and extrahepatic ducts were analysed, with seven (19%) and six (16%) cases, respectively, of lithiasis being detected on MRCP only (p<0.01 for both).

CONCLUSIONS

The results of our study confirm the diagnostic potential of MRCP in the study of the pancreaticobiliary duct system. In particular, the comparison between MRCP and US and MSCT indicates the superiority of MRCP in evaluating bile ducts and detecting stones in the common bile duct.

Postsurgical diagnostic evaluation of patients with differentiated thyroid carcinoma: comparison of ultrasound, iodine-131 scintigraphy and PET with fluorine-18 fluorodeoxyglucose

PURPOSE

The aim of this study was to compare the results of ultrasound (US), whole-body scintigraphy with iodine-131 (I-131 WBS) and positron emission tomography with fluorine-18 deoxyglucose (FDG-PET) in the follow-up of patients after thyroidectomy for differentiated thyroid carcinoma (DTC).

MATERIALS AND METHODS

Thirteen patients (3 men, 10 women) were evaluated by neck US, I-131 WBS and FDG-PET. In each patient six anatomical regions (right and left thyroid bed, right and left cervical region, right and left supraclavicular region) were investigated, for a total of 78 regions. Distant metastases were investigated by I-131 WBS and FDG-PET and considered separately in the analysis. Imaging findings were compared with the reference standards, such as fine-needle aspiration cytology (2), biopsy (4) or clinical-radiological studies (7).

RESULTS

US, FDG-PET and I-131 WBS showed concordant negative results in most (70, 90%) of the anatomical sites considered. In one patient with left cervical lymph node metastasis, the imaging techniques showed concordant positive results (1%). In the remaining 7 regions (9%), the imaging results were discordant; in particular, tumour lesions, nodal metastases (4) and thyroid bed recurrences (3) were detected by US only (3), by US and I-131 WBS (1) and by FDG-PET only (3). With regard to distant metastases, FDG-PET and I-131 WBS yielded concordant negative results in the majority (77%) of patients (9); in one patient only were the two imaging techniques concordant in their positive result. In the last three patients, the results were discordant; in particular, distant metastases were detected by I-131 WBS only in two patients and by FDG-PET only in one patient.

CONCLUSIONS

Our work indicates a fundamental role for US in evaluation of the neck after surgery for DTC. WBS is useful to determine differentiation of tumour lesions, to identify thyroid remnants and to look for distant metastases. FDG-PET has an important role in cases of dedifferentiated thyroid carcinoma in which WBS and thyroglobulin measurements are unable to detect tumour lesions.