Is a redefinition of the growth criteria of vestibular schwannomas needed?

PURPOSE: The natural history of vestibular schwannomas is poorly understood. Knowledge of growth rate and growth pattern is essential because the treatment strategy is based upon these. The purpose of this study was to determine the inter- and intraobserver variability in measuring VS size. MATERIALS AND METHODS: Two consultant neuroradiologists independently made three linear measurements (d1, d2, d3) using digital MRI scans. MRI scans from 72 patients diagnosed between 2002 and 2010 with VS were obtained. These patients had a total of 223 MRI scans. d1 (medio-lateral diameter) was made perpendicular to d2. d2 was made parallel to the posterior border of the petrous ridge, and d3 was a measure of the cranio-caudal height of the tumor. RESULTS: Limits of Agreement ranges are larger for interobserver reliability compared to intraobserver reliability. Measurement error for all diameters (except d1, intraobserver) is greater than 2mm. d1 measurements had the least variability and d3 measurements the highest variability, both for intra and interobserver measurements. CONCLUSIONS: The optimal method of estimating VS size needs further investigation, and measurements need to be standardized and clearly defined. d3 seems to be the most difficult diameter to measure reliably. Interobserver measurement error for all diameters is greater than 2mm. The current VS growth criterion of more than 1-2mm, used to triage patients to surgery, lies within this error range, and thus is problematic as a guide for clinical practice. We therefore suggest that the growth criterion for VS be redefined.

Remote ischemic perconditioning as an adjunct therapy to thrombolysis in patients with acute ischemic stroke: a randomized trial.

BACKGROUND AND PURPOSE: Remote ischemic preconditioning is neuroprotective in models of acute cerebral ischemia. We tested the effect of prehospital rPerC as an adjunct to treatment with intravenous alteplase in patients with acute ischemic stroke. METHODS: Open-label blinded outcome proof-of-concept study of prehospital, paramedic-administered rPerC at a 1:1 ratio in consecutive patients with suspected acute stroke. After neurological examination and MRI, patients with verified stroke receiving alteplase treatment were included and received MRI at 24 hours and 1 month and clinical re-examination after 3 months. The primary end point was penumbral salvage, defined as the volume of the perfusion-diffusion mismatch not progressing to infarction after 1 month. RESULTS: Four hundred forty-three patients were randomized after provisional consent, 247 received rPerC and 196 received standard treatment. Patients with a nonstroke diagnosis (n=105) were excluded from further examinations. The remaining patients had transient ischemic attack (n=58), acute ischemic stroke (n=240), or hemorrhagic stroke (n=37). Transient ischemic attack was more frequent (P=0.006), and National Institutes of Health Stroke Scale score on admission was lower (P=0.016) in the intervention group compared with controls. Penumbral salvage, final infarct size at 1 month, infarct growth between baseline and 1 month, and clinical outcome after 3 months did not differ among groups. After adjustment for baseline perfusion and diffusion lesion severity, voxelwise analysis showed that rPerC reduced tissue risk of infarction (P=0.0003). CONCLUSIONS: Although the overall results were neutral, a tissue survival analysis suggests that prehospital rPerC may have immediate neuroprotective effects. Future clinical trials should take such immediate effects, and their duration, into account. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00975962.

Selection of colon cancer patients for neoadjuvant chemotherapy by preoperative CT scan.

OBJECTIVE: Preoperative staging is essential to plan correct treatment of colon cancer and calls for objective, accurate methods for the introduction of neoadjuvant chemotherapy, which represents a new treatment option. PURPOSE: To evaluate the diagnostic accuracy of multislice computed tomography (CT) in local staging of colon cancer correlated with histopathological parameters, including criteria for adjuvant chemotherapy. MATERIAL AND METHODS: A total of 74 included patients had preoperative CT scans and surgical resection of their colon tumors. Tumor stage (T-stage), extramural tumor invasion (ETI), nodal stage (N-stage), extramural venous invasion (EVI) and the distance from tumor to nearest retroperitoneal fascia (DRF) were retrospectively assessed on the CT scan and compared blindly with the results of the pathological examination, including evaluation of the criteria for adjuvant chemotherapy. Advanced tumors were defined as T3 with ETI ≥5 mm or T4. RESULTS: Sixty-nine percent of the tumors were correctly T-staged by CT, 7% were overstaged and 24% were understaged. As to correct recognition of ETI on the CT scan, the observer was 73% accurate compared with histology (70% sensitivity (95% CI: 53-82%), 78% specificity (95% CI: 60-90%), 81% positive predictive value (PPV) (95% CI: 63-91%) and 66% negative predictive value (NPV) (95% CI: 49-80%). N-stage, EVI and DRF had poor accuracy: 53%, 53% and 64%. All patients with advanced tumors on CT fulfilled the criteria for adjuvant chemotherapy. Positive predictive value: 100% (95% CI: 88-100%). CONCLUSION: CT has a potential in the preoperative selection of advanced tumors suitable for neoadjuvant chemotherapy without overtreatment of low-risk patients.

Alterations of systemic and muscle iron metabolism in human subjects treated with low-dose recombinant erythropoietin.

The high iron demand associated with enhanced erythropoiesis during high-altitude hypoxia leads to skeletal muscle iron mobilization and decrease in myoglobin protein levels. To investigate the effect of enhanced erythropoiesis on systemic and muscle iron metabolism under nonhypoxic conditions, 8 healthy volunteers were treated with recombinant erythropoietin (rhEpo) for 1 month. As expected, the treatment efficiently increased erythropoiesis and stimulated bone marrow iron use. It was also associated with a prompt and considerable decrease in urinary hepcidin and a slight transient increase in GDF-15. The increased iron use and reduced hepcidin levels suggested increased iron mobilization, but the treatment was associated with increased muscle iron and L ferritin levels. The muscle expression of transferrin receptor and ferroportin was up-regulated by rhEpo administration, whereas no appreciable change in myoglobin levels was observed, which suggests unaltered muscle oxygen homeostasis. In conclusion, under rhEpo stimulation, the changes in the expression of muscle iron proteins indicate the occurrence of skeletal muscle iron accumulation despite the remarkable hepcidin suppression that may be mediated by several factors, such as rhEpo or decreased transferrin saturation or both.

[Renal pseudoaneurysm--a complication of nephrostomy]. / Renalt pseudoaneurisme--komplikation til nefrostomi.

Renal artery aneurysms are rare. These aneurysms have a potential for rupture, resulting in high mortality rates. Percutaneous renal procedures may lead to renovascular injury such as pseudoaneurysms. Regardless of the kidney region, puncture through a fornix of a calyx is relatively safe and only causes injury to an intrarenal vessel in a few percent of the cases. Renal pseudoaneurysm is usually diagnosed by renal angiography or computed tomography. Selective renal embolization is currently considered the most appropriate technique in the treatment for this complication.

Testing for recombinant human erythropoietin in urine: problems associated with current anti-doping testing.

BACKGROUND: the main action of recombinant human erythropoietin (rHuEpo) is to increase the oxygen carrying capacity of the blood. To prevent a possible misuse of rHuEpo, this is tested in urine samples collected from athletes by World Anti-Doping Agency (WADA)-accredited laboratories. Recently the test has met serious critiques, and the aims of the present study were to investigate the detection power of the test as well as the variability in the test power comparing the results of two WADA-accredited laboratories. METHODS: eight human subjects were studied for 7 wk and treated with rHuEpo for 4 wk with 2 wk of "boosting" followed by 2 wk of "maintenance" and a post period of 3 wk. Urine samples were obtained during all periods. RESULTS: laboratory A determined rHuEpo misuse in all subjects during the boosting period, whereas laboratory B found no misuse, with one sample to be negative, and the remaining seven to be suspicious. The detection rates decreased throughout the maintenance and post period when total hemoglobin mass and exercise performance were elevated. During this period, laboratory A found only two of 24 samples to be positive and three to be suspicious, and laboratory B found no positive or suspicious samples. CONCLUSION: this study demonstrates a poor agreement in test results comparing two WADA-accredited laboratories. Moreover, after the initial rHuEpo boosting period the power to detect rHuEpo misuse during the maintenance and post periods appears minimal.