CB is more accurate than FNAB and should be preferred in renal mass biopsy. FNAB may precede CB when an expert pathologist can immediately evaluate the samples. Renal biopsy influences renal mass management.

Objectives The diagnosis of acute pyelonephritis (APN) requires demonstration of parenchymal involvement. When no predisposing conditions are found, non-complicated APN is suspected and CT or MRI should be performed. Diffusion-weighted (DW) MRI might be useful, quicker and cheaper than the standard gadolinium-enhanced (GE) MRI. The aim of this study is to compare DW-MRI with GE-MRI to test its diagnostic accuracy in APN. Methods Of 318 consecutive patients hospitalised for APN, 279 underwent MRI. Four hundred and fourteen MR studies (first test and follow-up examinations) were gathered and data were processed using Diffusion Analysis software. DW-MRI has been compared with GE-MRI for evaluating diagnostic agreement. Results Two hundred and forty-four patients were diagnosed as having APN; 35 were negative. One hundred and sixty-three APN cases were considered non-complicated and selected for the study. Among the 414 MR examinations, comparing DW-MRI with GE-MRI, positive correlation was found in 258 cases, negative in 133. There were 14 falsenegatives and 9 false-positives. DW-MRI achieved sensitivity 95.2 %, specificity 94.9 %, positive predictive value 96.9 %, negative predictive value 92.3 % and accuracy 94.6 %. Conclusions DW-MRI is reliable for diagnosing noncomplicated APN. The high diagnostic agreement between DW-MRI and GE-MRI offers new perspectives in diagnostic management, enabling diagnosis of non-complicated APN without using ionising radiation or contrast media. Key Points • The diagnosis of acute pyelonephritis (APN) requires demonstration of renal involvement.• Hitherto magnetic resonance imaging required gadolinium enhancement (GE-MRI) to establish this diagnosis.• But diagnostic agreement between diffusion-weighted and GE-MRI offers new diagnostic opportunities.• Quantification of ADC values can help diagnose and monitor APN.• DW-MRI avoids ionising radiation and paramagnetic contrast medium administration.

The purpose of this study was to compare our experience with ultrasound (US)-guided percutaneous radiofrequency thermal ablation (RFA) of renal tumors with results of CT-guided and MRI-guided series in the current literature. Of 90 consecutive renal tumors treated with RFA in 71 patients, 87 lesions were ablated under US guidance. We performed a retrospective analysis of clinical outcome and safety. Results were then compared to published case series where CT and MRI guidances were used exclusively. In our series we had a major complication rate of 4.6%, whereas in CT- and MRI-based series it was 0-12% (mean, 2.2%) and 0-8.3% (mean, 4.1%), respectively. During follow-up (1-68 months; mean, 24 months) technical effectiveness was 89.7%, while it was between 89.5% and 96% in CT-guided series and between 91.7% and 100% in MRI-guided series. The size of successfully treated lesions (28 mm) was lower than that of partially-ablated lesions (36 mm; p = 0.004) and only central lesion location proved to be a negative prognostic factor (p = 0.009); in CT-guided series, positive prognostic factors were exophytic growth and size

Solitary fibrous tumor of the pleura (SFTP) is a mesenchymal tumor that tends to involve the pleura, and is also described in other thoracic and extrathoracic sites. SFTP usually presents as a peripheral mass abutting the pleural surface, to which it is attached by a broad base or by a pedicle that allows it to be mobile. SFTPs exist in benign and malignant forms. A precise pre-operative diagnosis can be arrived at with a cutting-needle biopsy, although most cases are diagnosed with postoperative histology and immunohistochemical analysis. In this pictorial essay, we review a large series of cases, with emphasis on the radiographic appearance of these lesions and their findings from computed tomography, magnetic resonance imaging, ultrasonography and positron emission tomography.