Predictive Value of In Vivo MR Spectroscopy With Semilocalization by Adiabatic Selective Refocusing in Differentiating Clear Cell Renal Cell Carcinoma From Other Subtypes.

OBJECTIVE. The purpose of this study is to evaluate the diagnostic value of in vivo MR spectroscopy (MRS) with semilocalization by adiabatic selective refocusing (semi-LASER MRS) in differentiating clear cell renal cell carcinoma (RCC) from the non-clear cell subtype. SUBJECTS AND METHODS. Sixteen patients with biopsy-proven RCC or masses highly suspicious for RCC were prospectively recruited to participate in the study. Single-voxel 1H spectra were acquired using a 3-T MRI system, with a semi-LASER sequence acquired for renal tumors in 14 patients and for healthy renal tissue (control tissue) in 12 patients. Offline processing of the MR spectra was performed. MRI and spectra analysis were performed independently by radiologists who were blinded to the reference histopathologic findings. RESULTS. Semi-LASER MRS was diagnostic for nine of 11 patients (82%) with histopathologically proven clear cell RCC, showing a strong lipid peak in seven patients and a weaker lipid resonance in two others, whereas control spectra showed weakly positive findings in only one patient. MRS findings were negative for lipid resonance in two of three patients (67%) with non-clear cell tumors and were weakly positive in another patient. Semi-LASER MRS had a high sensitivity and positive predictive value of 82% and 90%, respectively, in addition to a specificity of 67%, a negative predictive value of 50%, and overall accuracy of 79% for the detection of clear cell RCC. Lipid resonance was detected by MRS for four of six clear cell RCCs with no intravoxel fat on chemical-shift MRI. CONCLUSION. The preliminary results of the present study show that semi-LASER MRS is promising for the noninvasive discrimination of clear cell RCC from non-clear cell RCC on the basis of detection of lipid resonance and that it provides an incremental yield compared with chemical-shift MRI.

Structured reporting of MRI for perianal fistula.

OBJECTIVE: The purpose of this article is to review MRI technique, relevant anatomy, and MRI classification systems for the assessment of perianal fistulising disease. We present a stepwise approach to the assessment of perianal fistulas on MRI utilizing a systematic reporting format. CONCLUSION: MRI is invaluable for the assessment of perianal fistulas. A systematic report can help communicate the anatomy of complex fistulising disease to assist with optimal management.

Comparison of virtual bronchoscopy with fiberoptic bronchoscopy findings in patients exposed to sulfur mustard gas.

BACKGROUND: Fiberoptic bronchoscopy (FB) is the best modality for evaluation of tracheobronchial endoluminal lesions. Virtual bronchoscopy (VB) with the aid of computed tomography (CT) makes it possible to reconstruct endoscopic-like visualization of major airways. Sulfur mustard (SM) used during the Iraq-Iran war affects respiratory tracts and can lead to tracheobronchial stenosis. PURPOSE: To compare VB with FB in SM-exposed patients suspected for airway stenosis. MATERIAL AND METHODS: Thirty-one patients were evaluated with CT and bronchoscopic studies about 15 years after chemical attacks. The median age of patients was 40 years. Spiral CT scans were obtained and data were transferred to a workstation to generate VB images of major airways. Less than one week after CT scan, FB was performed. RESULTS: For the tracheal pathologies seen in FB, the sensitivity, specificity, and accuracy of VB was 90.9%, 95%, and 93.5% for tracheal stenosis, 40%, 96.2%, and 87.1% for vocal cord problems, 100%, 100%, and 100% for postoperative changes, and 100%, 96.7%, and 96.8% for intratracheal nodule. The inflammation of mucosal surface could not be assessed by VB. The bronchial pathologies seen in FB included eight cases of stenosis, and one case of nodule. Sensitivity, specificity, and accuracy of VB for detection of bronchial stenosis was 62.5%, 97.8% and 92.6%, respectively. Overall sensitivity, specificity and accuracy of VB in detecting tracheobronchial stenosis were 78.9%, 97.0%, and 92.9%, respectively. CONCLUSION: Our study indicates that VB is an accurate method for evaluating stenoses, endoluminal nodules, and poststenotic areas within the tracheobronchial tree of SM-exposed victims. This complementary method could be helpful in revealing hidden post-stenotic lesions and also better depict the long tracheal strictures and their actual length.