Evaluation of biliary abnormalities with 64-channel multidetector CT.

Precise preoperative assessment of the vascular and biliary anatomy is important in ensuring the safety of hepatobiliary surgical procedures, including laparoscopic cholecystectomy, living donor liver transplantation, and tumor resection of the liver. Endoscopic retrograde cholangiography and percutaneous transhepatic cholangiography clearly depict the biliary anatomy but are considered invasive procedures. Magnetic resonance cholangiopancreatography is noninvasive but sometimes fails to depict the normal intrahepatic bile ducts. Multidetector computed tomography (CT) has contributed greatly to the evaluation of the normal anatomy, anatomic variants, and disease extent in this setting. With 64-channel multidetector CT, high-resolution three-dimensional images can be reconstructed from isotropic data with a 0.625-mm section thickness. Because of its capacity for thin-section scanning and multiplanar reformation, 64-channel multidetector CT cholangiography can clearly demonstrate the biliary anatomy, a variety of anatomic variants, and the extent of disease--information that is indispensable for successful hepatobiliary surgery.

Non-contrast-enhanced MR venography of the upper limb: a comparative study of acquisitions with fresh blood imaging vs. time-of-flight methods.

Non-contrast-enhanced magnetic resonance venography (MRV) of the upper limb acquired by fresh blood imaging (FBI) was compared with time-of-flight (TOF)-MRV. Visualization of three veins (basilic, brachial, and cephalic veins), small branches, and fat suppression was evaluated with a four-point scale (0-3). FBI-MRV was significantly superior for the basilic veins and small venous branches and equivalent for the brachial and cephalic veins to TOF-MRV, with no difference in fat suppression. FBI-MRV would be useful in venous mapping and detection of thrombus.

MRI evaluation of residual tumor size after neoadjuvant endocrine therapy vs. neoadjuvant chemotherapy.

AIM: To investigate if there is any difference in evaluation of residual tumor size after neoadjuvant chemotherapy (NAC) and neoadjuvant endocrine therapy (NAE). METHODS: Seventy-eight tumors in 57 patients were prospectively enrolled. Residual tumor sizes in contrast-enhanced MRI after NAC and NAE were compared with those measured on surgical specimen by using linear regression analyses. The line slope values >1 indicates overestimation by MRI. Differences in types of shrinkage patterns: concentric shrinkage (CS) and dendritic shrinkage (DS) were also investigated. RESULTS: Fifty lesions were treated with NAC and 28 lesions were treated with NAE. Shrinkage patterns were CS in 33 lesions and in 45 lesions. The slopes values were 0.75 (R=0.92) and 0.70 (R=0.90) for NAC and NAE, respectively, and no significant difference was observed (p=0.46). However, they were 1.02 (R=0.92) and 0.68 (R=0.92), respectively for CS and DS with significant difference (p<0.01). The difference between CS and DS was found only in a subgroup with size by MRI >20 mm. CONCLUSION: Contrast enhanced MRI enabled fairly accurate measurement in NAE as well as in NAC.

Assessment of CAD-generated tumor volumes measured using MRI in breast cancers before and after neoadjuvant chemotherapy.

OBJECTIVE: To evaluate inter-observer agreement and the predictive value of tumor size measurements using MRI for breast cancer under neoadjuvant chemotherapy (NAC) by comparing the measurements of the longest diameters (LD), total enhanced volumes (TEV) and washout volumes (WOV). METHODS: Thirty-seven female breast cancer patients were prospectively enrolled from August 2008 to October 2010. Two of these patients had locally advanced disease. MRI examinations were acquired within 2 weeks before and after NAC. Interim scans were also conducted in 30 patients. Tumor resection was undertaken within 2 weeks after the cessation of NAC. MRI images were independently measured for LD, TEV and WOV by two experienced radiologists. Inter-observer agreement was evaluated using concordance correlation coefficients (CCCs). Tumor sizes after NAC were evaluated relative to their initial sizes for early prediction of a pathological complete response (pCR). RESULTS: The CCCs were 0.93 (CI: 0.90-0.95) for LD, 0.98 (CI: 0.97-0.98) for TEV and 0.99 (CI: 0.991-0.996) for WOV. All measurements had high inter-observer agreement, but the CCCs were significantly increased in the aforementioned order (P<0.0001). WOV measured after the completion of chemotherapy had significant discriminating ability (P=0.0056) when evaluated using receiver operating characteristic analysis, and was found to be superior to LD (P=0.045). The average WOV size was significantly smaller in pCR cases than in non-pCR cases (P=0.016). CONCLUSION: Computer-aided detection-generated tumor volumes had significantly higher inter-observer concordance than conventional LD measurements. WOV measurements had the highest concordance, and WOV could better predict pCR after NAC at smaller tumor sizes.