Joaquim Barceló

MR imaging of lipoma arborescens and the associated lesions

ObjectiveTo describe the typical features of lipoma arborescens on MR imaging with pathologic correlation and to evaluate the associated lesions within the joints.Design and patientsThe MR imaging findings of 32 patients with the diagnosis of lipoma arborescens of the knee (n=32) and shoulder (n=1) were reviewed. The diagnosis of lipoma arborescens was confirmed by the histologic findings in 12 cases and the other 21 cases were diagnosed by the characteristic MR imaging features. One patient had bilateral lipoma arborescens of the knee joint.ResultsMR imaging showed a typical pattern of villous lipomatous proliferation of the synovium in all cases, as a diffuse pattern in 79% (26/33) of cases and as a dominant mass-like lesion in 21% (7/33) of cases. The associated MR pathology in the knee was (n=32): joint effusion (100%), degenerative changes (87%), meniscal tear (72%), synovial cysts (38%), bone erosions (25%), chondromatosis (13%), patellar subluxation (6%) and discoid meniscus (3%). In all cases except two there was associated pathology of the knee. MR imaging showed an associated rotator cuff tear in the lipoma arborescens of the shoulder.ConclusionThe characteristic MR features of lipoma arborescens allows an accurate diagnosis of this rare lesion, which is almost always associated with other chronic pathology of the joint in the elderly.

Diagnostic value of apparent diffusion coefficients to differentiate benign from malignant vertebral bone marrow lesions

AIM The aim of this study is to evaluate the value of the apparent diffusion coefficient (ADC) obtained in diffusion-weighted (DW) MR sequences for the differentiation between malignant and benign bone marrow lesions. METHOD Forty-five patients with altered signal intensity vertebral bodies on conventional MR sequences were included. The cause of altered signal intensity was benign osteoporotic collapse in 16, acute neoplastic infiltration in 15, and infectious processes in 14; based on plain-film, CT, bone scintigraphy, conventional MR studies, biopsy or follow-up. All patients underwent isotropic DW MR images (multi-shot EPI, b values of 0 and 500 s/mm(2)). Signal intensity at DW MR images was evaluated and ADC values were calculated and compared between malignancy, benign edema and infectious spondylitis. RESULTS Acute malignant fractures were hyperintense compared to normal vertebral bodies on the diffusion-weighted sequence, except in one patient with sclerotic metastases. Mean ADC value from benign edema (1.9+/-0.39 x 10(-3) mm(2)/s) was significantly (p<0.0001) higher than untreated metastasic lesions (0.9+/-1.3 x 10(-3)mm (2)/s). Mean ADC value of infectious spondilytis (0.96+/-0.49 x 10(-3) mm(2)/s) was not statistically (p>0.05) different from untreated metastasic lesions. ADC value was low (0.75 x 10(-3) mm(2)/s) in one case of subacute benign fracture. CONCLUSIONS ADC values are a useful complementary tool to characterize bone marrow lesions, in order to distinguish acute benign fractures from malignant or infectious bone lesions. However, ADC values are not valuable in order to differentiate malignancy from infection.

Diffusion-weighted whole-body MR screening.

Diffusion-weighted sequence (DWI) of the entire body is a new promising technique feasible to evaluate multifocal disease. DWI has revealed great potential in the evaluation of patients with cancer or benign disease, as it supplies both quantitative and qualitative information of the whole body. The technical aspects of the diffusion-weighted whole body (DWWB) MR sequence are described with special emphasis on the processing and analysis of the imaging. DWWB MR sequence should be used combined with the other standard sequences such as FSE T1-weighted and STIR images. A complete whole-body MR imaging protocol including the DWI can be performed in less than 40 min. The possibilities, limitations and the preliminary clinical results of the whole-body MR imaging using a DWI of the entire body are reviewed.

Usefulness of Prebiopsy Multifunctional and Morphologic MRI Combined With Free-to-Total Prostate-Specific Antigen Ratio in the Detection of Prostate Cancer

OBJECTIVE The purpose of the study was to assess the predictive value for prostate cancer of MRI using morphologic (T2-weighted imaging [T2WI]) and functional (MR spectroscopy [MRS], diffusion-weighted imaging [DWI], and dynamic contrast-enhanced [DCE] MRI) sequences and the free-to-total prostate-specific antigen (PSA) ratio, alone and combined. MATERIALS AND METHODS This retrospective study included 70 patients (PSA level, > 4 ng/mL; free-to-total PSA ratio, < 20%) who underwent endorectal 1.5-T MRI before biopsy. We graded the likelihood of cancer on a 5-point scale. Imaging data were compared with histologic results on biopsy or prostatectomy. Accuracies were estimated from the area under receiver operating characteristic using the hemiprostate as the unit of analysis. A p value less than 0.05 denoted statistical significance. RESULTS The model combining all variables was more accurate than each variable alone (95.2% vs 73.5% for T2WI, 76.0% for MRS, 81.8% for DWI, 75.6% for DCE-MRI, and 78.8% for free-to-total PSA ratio). The complete model had accuracy similar to that of combining two imaging variables with free-to-total PSA ratio, especially free-to-total PSA ratio, T2WI, and DWI (94.0%); and free-to-total PSA ratio, DWI, and MRS (93.8%); with negative predictive values of 91.0% and 89.5%, respectively. The best models combining two imaging variables (MRS and DWI, 85.8%; T2WI and DWI, 84.8%) had accuracy that was similar to that of the combination of all imaging variables (87.3%) and higher than that of the best individual imaging variable (DWI, 81.8%), but lower than that of the complete model. CONCLUSION The combination of at least one functional technique with free-to-total PSA ratio is more accurate than combining only imaging variables in cancer detection. The use of more than two imaging variables does not increase the detection rate. Functional MRI has the potential to help avoid a large number of negative biopsies.

The value of endorectal MR imaging to predict positive biopsies in clinically intermediate-risk prostate cancer patients.

Abstract The aim of this study was to assess the effectiveness of endorectal MR imaging in predicting the positive biopsy results in patients with clinically intermediate risk for prostate cancer. We performed a prospective endorectal MR imaging study with 81 patients at intermediate risk to detect prostate cancer between January 1997 and December 1998. Intermediate risk was defined as: prostatic specific antigen (PSA) levels between 4 and 10 ng/ml or PSA levels in the range of 10–20 ng/ml but negative digital rectal examination (DRE) or PSA levels progressively higher (0.75 ng/ml year–1). A transrectal sextant biopsy was performed after the endorectal MR exam, and also of the area of suspicion detected by MR imaging. The accuracies were measured, both singly for MR imaging and combined for PSA level and DRE, by calculating the area index of the receiver operating characteristics (ROC) curve. Cancer was detected in 23 patients (28 %). Overall sensitivity and specificity of endorectal MRI was 70 and 76 %, respectively. Accuracy was 71 % estimated from the area under the ROC curve for the total patient group and 84 % for the group of patients with PSA level between 10–20 ng/ml. Positive biopsy rate (PBR) was 63 % for the group with PSA 10–20 ng/ml and a positive MR imaging, and 15 % with a negative MR exam. The PBR was 43 % for the group with PSA 4–10 ng/ml and a positive MR study, and 13 % with a negative MR imaging examination. We would have avoided 63 % of negative biopsies, while missing 30 % of cancers for the total group of patients. Endorectal MR imaging was not a sufficient predictor of positive biopsies for patients clinically at intermediate risk for prostate cancer. Although we should not avoid performing systematic biopsies in patients with endorectal MR imaging negative results, as it will miss a significant number of cancers, selected patients with a PSA levels between 10–20 ng/ml or clinical-biopsy disagreement might benefit from endorectal MR imaging.

Peripheral Zone Prostate Cancer in Patients with Elevated PSA Levels and Low Free-to-Total PSA Ratio: Detection with MR Imaging and MR Spectroscopy

PURPOSE To retrospectively assess the value of endorectal magnetic resonance (MR) imaging and MR spectroscopy combined with the free-to-total prostate-specific antigen (PSA) ratio for detecting prostate cancer in men with elevated PSA levels. MATERIALS AND METHODS The institutional review board approved the study, and all patients provided informed written consent. Endorectal MR imaging and MR spectroscopy were performed in 54 patients with PSA levels greater than 3 ng/mL but less than 15 ng/mL and free-to-total PSA ratio of less than 20%, followed by sextant biopsy in the peripheral zone. For each patient, MR imaging and MR spectroscopic findings, PSA level, and free-to-total PSA ratio were analyzed and compared with biopsy results and/or histopathologic tumor maps with regard to a sextant-modified distribution. The likelihood of cancer in each sextant according to MR and MR spectroscopic findings was graded independently on a scale of 1 (benign) to 5 (malignant). Detection accuracy and a multivariate logistic regression analysis were used to determine the most accurate combination of imaging, and clinical tests were used to detect prostate cancer according to the area under the receiver operating characteristic curve (AUC). RESULTS The model incorporating MR imaging, MR spectroscopy, and free-to-total PSA ratio (AUC = 97.5%) was significantly more accurate in predicting prostate cancer than models using MR imaging alone (AUC = 85.1%; P = .007), MR spectroscopy alone (AUC = 87.2%; P = .041), or MR imaging and free-to-total PSA ratio combined (AUC = 90.8%; P = .038). CONCLUSION MR and MR spectroscopy combined with free-to-total PSA ratio improves the predictive value for prostate cancer detection.

Soft-tissue tumors update: MR imaging features according to the WHO classification

Soft-tissue tumors are a large and heterogeneous group of neoplasms. Hence, classification is often difficult. The most effective management decisions are made when a working group participates in the same diagnostic standard criteria in the evaluation of soft-tissue tumors. The purpose of this pictorial review is to highlight the new and the less well-known features on magnetic resonance (MR) imaging of soft-tissue tumors according to the World Health Organization (WHO) classification established in 2002. The article depicts the major changes of the WHO classification since it was established in 2002 and the most significant findings on MR imaging, thereby providing an update.

Prostate cancer detection: magnetic resonance (MR) spectroscopic imaging.

Magnetic resonance spectroscopic imaging (MRSI) represents a noninvasive technique to extend the diagnostic evaluation of prostatic cancer, beyond the morphologic information provided by MR imaging throughout the detection of cellular metabolites (choline and citrate). MRSI combined with the anatomical information provided by MRI can improve the assessment cancer location and extent within the prostate, extracapsular spread and cancer aggressiveness; both before and after treatment. We review the performance of MRI with MRSI and the role in the detection, localization, staging and management of the patient pre- and posttherapy for prostate cancer.

Resonancia magnética de todo el cuerpo con técnica de difusión (PET virtual) para el cribado de las metástasis óseas

Objetivo. Presentar nuestra experiencia preliminar en resonancia magnetica de cuerpo entero (RMCE) en el cribado de metastasis oseas, anadiendo la secuencia de difusion de todo el cuerpo. Material y metodos. Veinticuatro pacientes con neoplasias malignas fueron estudiados con gammagrafia osea (GO) y RM de cuerpo entero anadiendo secuencia de difusion. La RMCE se realizo con un equipo de 1.5 T en 3 estaciones en el plano coronal FSE T1 y STIR y plano sagital FSE T1 del raquis. Se anadio la secuencia de difusion (b: 600 s/mm2) de RMCE en el plano axial en 5 estaciones diferentes y presentacion iconografica en reconstruccion en el plano coronal con inversion del contraste para obtener una imagen similar a la de la tomografia por emision de positrones (PET) (PET virtual). Los hallazgos de la GO y la RM fueron comparados para la existencia o no de metastasis oseas, valorando al paciente tanto globalmente como por regiones oseas. Las lesiones metastasicas se confirmaron por biopsia o seguimiento en 6-8 meses Resultados. Globalmente, la RMCE con difusion fue superior a la GO, sensibilidad 100% (GO 71%), especificidad 90% (GO 80%) y fiabilidad 96% (GO 75%). Valorando por regiones oseas, la RM tuvo tambien unos resultados superiores a la GO: sensibilidad 96% (GO 52%). En difusion las metastasis liticas fueron hiperintensas en todos los casos, con un valor ADC superior al hueso sano pero inferior a las lesiones con edema agudo de etiologia benigna. La RMCE mostro, ademas, hallazgos extraoseos desconocidos relacionados con el tumor y en un 42% de los pacientes metastasis extraoseas. Conclusiones. La RMCE anadiendo la secuencia de difusion es un metodo eficaz para detectar metastasis oseas con fiabilidad superior a la gammagrafia; aportando ademas informacion sobre lesiones extraoseas. Las metastasis liticas se comportan de forma hiperintensa en difusion y tienen un valor ADC inferior al edema benigno.

Usefulness of magnetic resonance imaging in prostate cancer

In the last decade, technical advances in magnetic resonance imaging (MRI) have made it the technique of choice in the overall management of patients with suspected or confirmed prostate cancer. MR makes it possible to acquire information about morphology and function in the same examination by using techniques like spectroscopy, diffusion, and dynamic sequences with intravenous contrast material administration. Moreover, MRI enables both focused study of the prostate gland and of regional and/or whole-body involvement, depending on the clinical indications, in less than an hour. The main clinical indications for MRI of the prostate are a) staging local, regional, and/or remote disease; b) detecting prostate cancer or guiding prostate biopsy in cases of clinical suspicion or negative findings in previous biopsy specimens; and c) monitoring the response to treatment. It is important to know the different protocols with specific MRI sequences for the prostate, depending on the different clinical indications, to ensure that they are performed and interpreted correctly. This article provides up-to-date information about the use of MRI for the study of the prostate to show how the morphological and functional information can be used in clinical practice.