Valdair Francisco Muglia

Magnetic resonance imaging of scrotal diseases: when it makes the difference

OBJECTIVES To investigate the utility of magnetic resonance imaging (MRI) after inconclusive sonography in the evaluation of scrotal disease. METHODS From 1993 to 1999, 622 patients underwent ultrasonography (US) with state-of-the-art equipment to evaluate scrotal diseases. Twenty-six patients, two with bilateral and distinct diseases (age range 1--63 years, mean 33), had an inconclusive sonogram and were sent for MRI. The MRI results were compared with previous US reports and with the final diagnosis. RESULTS MRI yielded additional and correct information (compared with US), coincident with the final diagnosis in 23 cases (82.1%). In regard to lesions suspected of malignancy at US (17 cases), MRI had a great concordance with the final diagnosis and was statistically significant (P <0.002, kappa test). CONCLUSIONS The results of our study indicate that MRI could help elucidate scrotal dilemmas found at US, although the small percentage of inconclusive sonograms confirms this technique as the first choice when imaging is required in scrotal diseases.

Renal cell carcinoma: histological classification and correlation with imaging findings

Renal cell carcinoma (RCC) is the seventh most common histological type of cancer in the Western world and has shown a sustained increase in its prevalence. The histological classification of RCCs is of utmost importance, considering the significant prognostic and therapeutic implications of its histological subtypes. Imaging methods play an outstanding role in the diagnosis, staging and follow-up of RCC. Clear cell, papillary and chromophobe are the most common histological subtypes of RCC, and their preoperative radiological characterization, either followed or not by confirmatory percutaneous biopsy, may be particularly useful in cases of poor surgical condition, metastatic disease, central mass in a solitary kidney, and in patients eligible for molecular targeted therapy. New strategies recently developed for treating renal cancer, such as cryo and radiofrequency ablation, molecularly targeted therapy and active surveillance also require appropriate preoperative characterization of renal masses. Less common histological types, although sharing nonspecific imaging features, may be suspected on the basis of clinical and epidemiological data. The present study is aimed at reviewing the main clinical and imaging findings of histological RCC subtypes.

Revisão radiológica de 173 casos consecutivos de paracoccidioidomicose

OBJECTIVE: To determine the incidence of most significant radiological findings of paracoccidioidomycosis and to verify its possible variants. MATERIALS AND METHODS: One hundred and seventy-three cases of paracoccidioidomycosis presented between 1970 and 1980 were reviewed, including their radiological workup reanalysis by at least two experienced radiologists. RESULTS: Ninety-four cases were pulmonary only and 38 were pulmonary associated with ganglial, visceral and osseous lesions or in association with tuberculosis. There was no pulmonary involvement in 41 cases, presenting small bowel, viscera, bone lesions, or a combination of these. Most significant radiological findings in cases of pulmonary involvement were bilateral, diffuse reticular and nodular interstitial infiltrate, followed by the diffuse bilateral alveolar form. Visceral and gastrointestinal tract lesions presented predominantly with liver, jejunum and ileum involvement. Lymph nodal involvement was predominantly diffuse, abdominal or peripheral. In bones, osteolytic lesions affected predominantly long bones and clavicle. CONCLUSION: Paracoccidioidomycosis is a granulomatous disease commonly found in Brazil, primarily affecting lungs, caused by inhalation of fungus spores. Other rare or less frequent forms of the disease should be taken into consideration for differential diagnosis.

Prostate cancer: prediction of biochemical failure after external-beam radiation therapy--Kattan nomogram and endorectal MR imaging estimation of tumor volume.

PURPOSE To determine whether magnetic resonance (MR) imaging and MR spectroscopic imaging findings can improve predictions made with the Kattan nomogram for radiation therapy. MATERIALS AND METHODS The institutional review board approved this retrospective HIPAA-compliant study. Ninety-nine men who underwent endorectal MR and MR spectroscopy before external-beam radiation therapy for prostate cancer (January 1998 to June 2007) were included. Linear predictors were calculated with input variables from the study sample and the Kattan original coefficients. The linear predictor is a single weighted value that combines information of all predictor variables in a model, where the weight of each value is its association with the outcome. Two radiologists independently reviewed all MR images to determine extent of disease; a third independent reader resolved discrepancies. Biochemical failure was defined as a serum prostate-specific antigen level of 2 ng/mL (2 μg/L) or more above nadir. Cox proportional hazard models were used to determine the probabilities of treatment failure (biochemical failure) in 5 years. One model included only the Kattan nomogram data; the other also incorporated imaging findings. The discrimination performance of all models was determined with receiver operating characteristics (ROC) curve analyses. These analyses were followed by an assessment of net risk reclassification. RESULTS The areas under the ROC curve for the Kattan nomogram and the model incorporating MR imaging findings were 61.1% (95% confidence interval: 58.1%, 64.0%) and 78.0% (95% confidence interval: 75.7%, 80.4%), respectively. Comparison of performance showed that the model with imaging findings performed significantly better than did the model with clinical variables alone (P < .001). Overall, the addition of imaging findings led to an improvement in risk classification of about 28%, ranging from approximately a minimum of 16% to a maximum of 39%, depending on the risk change considered important. CONCLUSION MR imaging data improve the prediction of biochemical failure with the Kattan nomogram after external-beam radiation therapy for prostate cancer. The number needed to image to improve the prediction of biochemical failure in one patient ranged from three to six.

Prótese vascular derivada do látex

BACKGROUND: The development of vascular grafts has been crucial for advances and achievements in reconstructive vascular surgery over the past 5 decades. OBJECTIVES: To develop a new model of microperforated vascular graft using fabric covered with a natural latex-derived polymer taken from Hevea brasiliensis and assess its patency, thrombogenicity, biocompatibility and healing process, besides some mechanical properties (adaptability, elasticity, impermeability and possibility of suture), using expanded polytetrafluoroethylene graft as control. METHODS: Fifteen dogs were divided into three groups of five animals. The microperforated latex graft was implanted in all dogs and the expanded polytetrafluoroethylene graft was implanted in the contralateral pelvic limb. Postoperative follow-up was 4, 8 and 12 weeks. Analysis of results was performed according to clinical evaluation of pulses, complications (fluid collection, dehiscence, granuloma and infection), arteriography, macroscopic analysis and scanning electron micrography. RESULTS: Statistical tests revealed no significant differences (p > 0.05) concerning post-operative complications and graft patency. Both grafts were properly integrated to surrounding tissues, with connective tissue formed by collagen fibers. A neointimal layer covering all extension of the luminal surface was observed in the microperforated latex graft. Conversely, the endothelial development over the neointimal surface was limited to regions adjacent to the anastomoses in the expanded polytetrafluoroethylene graft. CONCLUSIONS: The microperforated latex graft showed satisfactory structural qualities (adaptability, elasticity, impermeability and possibility of suture) as a vascular substitute. It stimulated endothelial growth beyond contact regions with the artery in anastomoses and was biocompatible in the dogs arterial system, presenting adequate tissue integration.

Ressonância magnética do tórax: Aplicações tradicionais e novas, com ênfase em pneumologia

The objective of the present review study was to present the principal applications of magnetic resonance imaging (MRI) of the chest, including the description of new techniques. Over the past decade, this method has evolved considerably because of the development of new equipment, including the simultaneous interconnection of phased-array multiple radiofrequency receiver coils and remote control of the table movement, in addition to faster techniques of image acquisition, such as parallel imaging and partial Fourier acquisitions, as well as the introduction of new contrast agents. All of these advances have allowed MRI to gain ground in the study of various pathologies of the chest, including lung diseases. Currently, MRI is considered the modality of choice for the evaluation of lesions in the mediastinum and in the chest wall, as well as of superior sulcus tumors. However, it can also facilitate the diagnosis of lung, pleural, and cardiac diseases, as well as of those related to the pulmonary vasculature. Pulmonary MRI angiography can be used in order to evaluate various pulmonary vascular diseases, and it has played an ever greater role in the study of thromboembolism. Because cardiac MRI allows morphological and functional assessment in the same test, it has also become part of the clinical routine in the evaluation of various cardiac diseases. Finally, the role of MRI has been extended to the identification and characterization of pulmonary nodules, the evaluation of airway diseases, and the characterization of pleural effusion.

Radiological reports: a comparison between the transmission efficiency of information in free text and in structured reports

INTRODUCTION: This work proposes to improve the transmission of information between requiring physicians and radiologists. OBJECTIVES: Evaluate the implementation of a structured report (SR) in a university hospital. METHODS: A model of a structured report for thyroid sonography was developed according to information gathered from radiologists and endocrinologists working in this field. The report was based on a web platform and installed as a part of a Radiological Information System (RIS) and a Hospital Information System (HIS). The time for the report generation under the two forms was evaluated over a four-month period, two months for each method. After this period, radiologists and requiring physicians were questioned about the two methods of reporting. RESULTS: For free text, 98 sonograms were reported to have thyroids with nodules in an average time of 8.71 (+/−4.11) minutes, and 59 sonograms of thyroids without nodules were reported in an average time of 4.54 (+/− 3.97) minutes. For SR, 73 sonograms in an average time of 6.08 (+/−3.8) minutes for thyroids with nodules and 3.67 (+/−2.51) minutes for thyroids without nodules. Most of the radiologists (76.2%) preferred the SR, as originally created or with suggested changes. Among endocrinologists, 80% preferred the SR. DISCUSSION: From the requiring physicians’ perspective, the SR enabled standardization and improved information transmission. This information is valuable because physicians need reports prepared by radiologists. CONCLUSIONS: The implementation of a SR in a university hospital, under an RIS/HIS system, was viable. Radiologists and endocrinologists preferred the SR when compared to free text, and both agreed that the former improved the transmission of information.

Complicações do uso intravenoso de agentes de contraste à base de gadolínio para ressonância magnética

Os agentes de contraste a base de gadolinio sao muito mais seguros que o contraste iodado, no entanto, existem complicacoes que devem ser reconhecidas, para orientacao e tratamento adequados. A incidencia total de reacoes adversas aos meios de contraste em ressonância magnetica varia entre 2% e 4%. Casos de reacoes adversas agudas maiores ao gadolinio, como laringoespasmo e choque anafilatico, sao raros. As complicacoes cronicas com o uso do gadolinio tambem existem e, recentemente, foi descrita associacao entre seu uso e uma doenca dermatologica rara que ocorre em pacientes com insuficiencia renal. A fibrose nefrogenica sistemica foi tema de anuncio publico oficial pela agencia americana de regulacao de drogas, a Food and Drug Administration. Esta doenca progressiva caracteriza-se pelo espessamento e endurecimento da pele e fibrose, que podem acometer outras partes do corpo. Os pacientes que desenvolveram esta complicacao apresentavam insuficiencia renal cronica, estavam em acidose metabolica e foram submetidos a angiografia por ressonância magnetica, provavelmente com injecao de grande volume de contraste paramagnetico. Esta revisao tem o objetivo de apresentar uma descricao sucinta dos tipos de meios de contraste a base de gadolinio, possiveis complicacoes e medidas para prevencao e tratamento destas.Gadolinium-based contrast agents are much safer than the iodinated ones; however complications may occur and should be recognized for appropriate orientation and management. The total incidence of adverse reactions to contrast agents in magnetic resonance imaging ranges between 2% and 4%. Cases of severe acute reactions to gadolinium, such as laryngospasm and anaphylactic shock, are rare. Chronic complications secondary to the use of gadolinium also can occur and, recently an association between its use and a rare dermatologic disease occurring in patients with renal failure has been reported. Nephrogenic systemic fibrosis was the subject of an official health notification issued by the American Food and Drug Administration. This progressive disease is characterized by hardened skin with fibrotic nodules and plaques which may involve other parts of the body. Patients who have been affected by this disorder presented chronic renal failure, with metabolic acidosis and had been submitted to magnetic resonance angiography, probably involving exposure to large amounts of intravenous paramagnetic contrast. This review is aimed at presenting a succinct description of the gadolinium-based contrast agent types, possible secondary complications, their preventive measures and management.

Multiparametric MRI of the prostate: diagnostic performance and interreader agreement of two scoring systems.

OBJECTIVE To compare the diagnostic accuracies and interreader agreements of the Prostate Imaging Reporting and Data System (PI-RADS) v. 2 and University of California San Francisco (UCSF) multiparametric prostate MRI scale for diagnosing clinically significant prostate cancer. METHODS This institutional review board-approved retrospective study included 49 males who had 1.5 T endorectal MRI and prostatectomy. Two radiologists scored suspicious lesions on MRI using PI-RADS v. 2 and the UCSF scale. Percent agreement, 2 × 2 tables and the area under the receiver operating characteristic curves (Az) were used to assess and compare the individual and overall scores of these scales. Interreader agreements were estimated with kappa statistics. RESULTS Reader 1 (R1) detected 78 lesions, and Reader 2 (R2) detected 80 lesions. Both identified 52 of 65 significant cancers. The Az for PI-RADS v. 2 and UCSF scale for R1 were 0.68 and 0.69 [T2 weighted imaging (T2WI)], 0.75 and 0.68 [diffusion-weighted imaging (DWI)] and 0.64 and 0.72 (overall score), respectively, and were 0.72 and 0.75 (T2WI), 0.73 and 0.67 (DWI) and 0.66 and 0.75 (overall score) for R2. The dynamic contrast-enhanced percent agreements between scales were 100% (R1) and 95% (R2). PI-RADS v. 2 DWI of R1 performed better than UCSF DWI (Az = 0.75 vs Az = 0.68; p = 0.05); no other differences were found. The interreader agreements were higher for PI-RADS v. 2 (T2WI: 0.56 vs 0.42; DWI: 0.60 vs 0.46; overall: 0.61 vs 0.42). The UCSF approach to derive the overall PI-RADS v. 2 scores increased the Az for the identification of significant cancer (R1 to 0.76, p < 0.05; R2 to 0.71, p = 0.35). CONCLUSION Although PI-RADS v. 2 DWI score may have a higher discriminatory performance than the UCSF scale counterpart to diagnose clinically significant cancer, the utilization of the UCSF scale weighing system for the integration of PI-RADS v. 2 individual parameter scores improved the accuracy its overall score. ADVANCES IN KNOWLEDGE PI-RADS v. 2 is moderately accurate for the identification of clinically significant prostate cancer, but the utilization of alternative approaches to derive the overall PI-RADS v. 2 score, including the one used by the UCSF system, may improve its diagnostic accuracy.

Magnetization transfer ratio as a predictor of malignancy in breast lesions: preliminary results.

MRI is an important tool for investigating breast cancer. Although recognized as the method of choice for screening high‐risk patients, and for other indications the role of MRI for lesion characterization remains controversial. Recently some authors have advocated the use of morphologic and postcontrast features for this purpose. Quantitative breast MRI techniques have not been applied extensively in breast diseases. Magnetization transfer (MT) is a quantitative MR technique commonly used to investigate neurological diseases. In breast diseases the use of MT has been limited to improving visualization of areas of enhancement in postcontrast images. The purpose of this study was to evaluate the feasibility and utility of MT in discriminating benign from malignant breast lesions. Fifty‐two lesions, BIRADS 4 and 5, from 49 patients, were prospectively evaluated using the MT ratio (MTR). Patients were divided into two groups: benign and malignant lesions. The MTR of fat, pectoralis major muscle, fibroglandular tissue, and breast lesions were calculated. A statistically significant difference was found between MTR from benign and malignant lesions (P < 0.001). Preliminary results suggest that MT can be used to evaluate breast lesions. Further studies are necessary to better define the utility and applicability of this technique. Magn Reson Med 59:1030–1034, 2008.