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

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.

MR imaging of a malignant schwannoma and an osteoblastoma with fluid-fluid levels. Report of two new cases.

One case of malignant schwannoma of the sacrum and another of occipital osteoblastoma were evaluated by MR imaging. Both tumors showed fluid-fluid levels with different signal intensities in the sequences performed. Pathologic examination revealed hemorrhagic fluid in both tumors. Malignant schwannoma and osteoblastoma should be included in the list of bone and soft-tissue with fluid-fluid levels. Our data confirm the non-specificity of this finding, which only suggests the presence of previous intratumoral hemorrhage.

The effect of repetitive magnetic stimulation on localized musculoskeletal pain.

Current magnetic coil stimulators can efficiently activate neural structures without deep electrode placement and the local discomfort associated with transcutaneous electrical stimulation used in pain control. We tested the possibility of reducing pain in patients with localized musculoskeletal processes by applying repetitive magnetic stimulation on the tender body region. Thirty patients were randomized to receive 40 min of real or sham magnetic stimulation. After a single session, real magnetic stimulation significantly exceeded the sham effect: a 101-point pain score decreased by 59% in the treated group and 14% in sham-treated patients (z = -3.26, p = 0.001). The pain relief attained regularly persisted for several days. Results indicate that powerful magnetic coil stimulation can efficiently reduce pain originating from localized musculoskeletal injuries.

The role of the circle of Willis in carotid occlusion: assessment with phase contrast MR angiography and transcranial duplex.

PURPOSE: To study the collateral pathways recruited after occlusion of the internal carotid artery (ICA), and to evaluate its influence on the impairment of hemispheric blood flow supply and development of low flow infarcts. METHODS: 38 patients with ICA occlusion (18 asymptomatic; five transient ischaemic attacks; and 15 strokes) were included. Infarcts on cerebral MR scanning were categorised in order to differentiate patients with territorial infarcts or no lesion (group I; n = 22) from those with brain damage due to low flow (group II; n = 16). Patency and direction of flow in the communicating arteries were assessed by means of cine phase contrast MR angiography (PC-MRA). Flow velocity in the middle cerebral artery (MCA) was measured by means of transcranial Duplex (TCD). RESULTS: Cine PC-MRA revealed a reversed ophthalmic artery blood flow ipsilateral to the ICA occlusion in all except two patients in group I and one patient in group II (NS). Posterior to anterior flow in the ipsilateral posterior communicating artery (PCoA) was detected in 16 (73%) patients in group I and in 13 (81%) in group II (NS). In contrast, reversed blood flow in the ipsilateral A1 segment of the anterior cerebral artery, through a patent anterior communicating artery (ACoA), was identified in 19 (86%) patients of group I, vs. 7 (44%) of group II (p = 0.005). The relative risk of low-flow infarcts was significantly higher in those cases with non-functioning ACoA (odds ratio = 8.1; p < 0.05). TCD showed a lower peak systolic velocity (PSV) in the ipsilateral MCA than in the contralateral one (60 +/- 9 cm/s vs. 90 +/- 11 cm/s; p < 0.005). Those patients without crossed flow through the ACoA, showed an even lower PSV in the ipsilateral MCA (55 +/- 7 cm/s vs. 64 +/- 9 cm/s; p = 0.03). CONCLUSIONS: These data suggest that even though ICA occlusion may occur without cerebral damage, collateral blood supply is not enough to maintain normal hemispheric perfusion. The ACoA may be a key collateral pathway as a non-functioning ACoA is associated with an increased risk of developing low-flow infarcts.

[Aneurysm of the renal artery in youngsters: presentation of a case and review of the literature]. / Aneurismas de la arteria renal en jóvenes: presentación de un caso y revisión bibliográfica.

The case of a young man with an aneurysm of the renal artery, causing vasculorenal hypertension, and surgically treated, is presented. The present concepts of incidence, etiology, renal aneurysm-hypertension association, surgical indications and rupture risk, are exposed.