Ewing sarcoma versus osteomyelitis: differential diagnosis with magnetic resonance imaging.

OBJECTIVE: To find and evaluate characteristic magnetic resonance imaging (MRI) patterns for the differentiation between Ewing sarcoma and osteomyelitis. MATERIALS AND METHODS: We identified 28 consecutive patients referred to our department for MRI (1.5 T) of an unclear bone lesion with clinical symptoms suggestive of Ewing sarcoma or osteomyelitis. MRI scans were re-evaluated by two experienced radiologists, typical MR imaging features were documented and a diagnostic decision between Ewing sarcoma and osteomyelitis was made. Statistical significance of the association between MRI features and the biopsy-based diagnosis was assessed using Fisher's exact test. RESULTS: The most clear-cut pattern for determining the correct diagnosis was the presence of a sharp and defined margin of the bone lesion, which was found in all patients with Ewing sarcoma, but in none of the patients with osteomyelitis (P < 0.0001). Contrast enhancing soft tissue was present in all cases with Ewing sarcoma and absent in 4 patients with osteomyelitis (P = 0.0103). Cortical destruction was found in all patients with Ewing sarcoma, 4 patients with osteomyelitis did not present any cortical reaction (P = 0.0103). Cystic or necrotic areas were identified in 13 patients with Ewing sarcoma and in 1 patient with osteomyelitis (P = 0.004). Interobserver reliability was very good (kappa = 1) in Ewing sarcoma and moderate (kappa = 0.6) in patients with osteomyelitis. CONCLUSIONS: A sharp and defined margin, optimally visualized on T1-weighted images in comparison to short tau inversion recovery (STIR) images, is the most significant feature of Ewing sarcoma in differentiating from osteomyelitis.

Lornoxicam characteristically modulates cerebral pain-processing in human volunteers: a functional magnetic resonance imaging study.

BACKGROUND: Lornoxicam like other non-steroidal anti-inflammatory drugs (NSAIDs) is widely used for postoperative pain therapy. Evaluation of the effect of lornoxicam on cerebral processing of surgical pain was thus the aim of the present functional magnetic resonance imaging (fMRI) study. METHODS: An fMRI-compatible pain model that mimics surgical pain was used to induce pain rated 4-5 on a visual analogue scale (VAS) at the anterior margin of the right tibia in volunteers (n=22) after i.v. administration of saline (n=11) or lornoxicam (0.1 mg kg(-1)) (n=11). RESULTS: Lornoxicam, which significantly reduced pain sensation [VAS: mean (sd) 4.6 (0.7) vs 1.2 (1.5)], completely suppressed pain-induced activation in the SII/operculum, anterior cingulate cortex, insula, parietal (inferior), prefrontal (inferior, medial), temporal (inferior, medial/superior) lobe, cerebellum, and contralateral (e.g. left-sided) postcentral gyrus (SI). Only the hippocampus and the contralateral superior parietal lobe (BA 7) were activated. CONCLUSIONS: As compared with saline, lornoxicam typically suppressed pain-induced brain activation in all regions except the hippocampus. Furthermore, de novo activation was found in the contralateral, superior parietal lobe (BA 7).

Myocardial edema in acute myocarditis: relationship of T2 relaxometry and late enhancement burden by using dual-contrast turbo spin-echo MRI.

To quantify myocardial edema by using a T2 relaxometry approach with a dual-contrast turbo spin-echo (dcTSE) sequence in patients with acute myocarditis regarding focal late gadolinium enhancement (LGE) burden. CMR T2 relaxometry was performed in 39 patients (age 41 ± 19 years; 36% women) with LGE in a typical myocarditis pattern and in ten healthy volunteers (age 46 ± 12; 60% woman). dcTSE sequence (echo time 29 and 75 ms, respectively) was used for T2 mapping, analysis were performed on the basis of region of interest (ROI). Myocardial T2 relaxation times (T2 RT) in patients-ROI with focal LGE were significantly (p < 0.001) higher than T2 RT in patients-ROI without apparent LGE pattern (65 ms (IQR 36-95) vs. 60 ms (IQR 26-88), respectively). T2 RT in healthy volunteers [55 ms (IQR 35-71)] were significantly lower than in patients ROI with or without focal LGE-pattern (p < 0.001, respectively). T2 RT assessed by dcTSE are significantly higher in patients segments with and without focal LGE compared to normal controls, supporting a global myocardial inflammatory process in acute myocarditis. Furthermore, this quantitative T2-mapping approach highlights the potential to identify patients with diffuse myocarditis.

Survival with full neurologic recovery and no cerebral pathology after prolonged cardiopulmonary resuscitation with vasopressin in pigs.

OBJECTIVES: We sought to determine the effects of vasopressin and saline placebo in comparison with epinephrine on neurologic recovery and possible cerebral pathology in an established porcine model of prolonged cardiopulmonary resuscitation (CPR). BACKGROUND: It is unknown whether increased cerebral blood flow during CPR with vasopressin is beneficial with regard to neurologic recovery or detrimental owing to complications such as cerebral edema after return of spontaneous circulation. METHODS: After 4 min of cardiac arrest, followed by 3 min of basic life support CPR, 17 animals were randomly assigned to receive every 5 min either vasopressin (0.4, 0.4 and 0.8 U/kg; n = 6), epinephrine (45, 45 and 200 microg/kg; n = 6) or saline placebo (n = 5). The mean value +/- SEM of aortic diastolic pressure was significantly (p < 0.05) higher 90 s after each of three vasopressin versus epinephrine versus saline placebo injections (60 +/- 3 vs. 45 +/- 3 vs. 29 +/- 2 mm Hg; 49 +/- 5 vs. 27 +/- 3 vs. 23 +/- 1 mm Hg; and 50 +/- 6 vs. 21 +/- 3 vs. 16 +/- 3 mm Hg, respectively). After 22 min of cardiac arrest, including 18 min of CPR, defibrillation was attempted to achieve return of spontaneous circulation. RESULTS: All the pigs that received epinephrine and saline placebo died, whereas all pigs on vasopressin survived (p < 0.05). Neurologic evaluation 24 h after successful resuscitation revealed only an unsteady gait in all vasopressin-treated animals; after 96 h, magnetic resonance imaging revealed no cerebral pathology. CONCLUSIONS: During prolonged CPR, repeated vasopressin administration, but not epinephrine or saline placebo, ensured long-term survival with full neurologic recovery and no cerebral pathology in this porcine CPR model.

Diffusion-weighted MRI differentiates the Parkinson variant of multiple system atrophy from PD.

OBJECTIVE AND BACKGROUND: Routine MRI as well as MR volumetry and MRS have been shown to contribute to the differential diagnosis of the Parkinson variant of multiple system atrophy (MSA-P) and PD. However, it is currently unknown whether diffusion-weighted imaging (DWI) discriminates these disorders. METHODS: Ten patients with MSA-P (mean age, 64 years) were studied, 11 with PD (mean age, 64 years), and seven healthy volunteers (mean age, 59 years) matched for age and disease duration. Regional apparent diffusion coefficients (rADC) were determined in different brain regions including basal ganglia, gray matter, white matter, substantia nigra, and pons. RESULTS: Patients with MSA-P had higher putaminal rADC (median 0.791 x 10(3)/mm(2)/s) than both patients with PD (median 0.698 x 10(3)/mm(2)/s, p < 0.001) and healthy volunteers (median 0.727 x 10(3)/mm(2)/s, p < 0.001). There were no significant differences in putaminal rADC between patients with PD and healthy volunteers. Moreover, none of the putaminal rADC values in the PD and control group surpassed the lowest value in the MSA-P group. There were no significant group differences in the rADC values in other brain regions such as pons, substantia nigra, globus pallidus, caudate nucleus, thalamus, or gray and white matter. Putaminal rADC values correlated significantly with Unified PD Rating Scale OFF scores in patients with MSA as measured by the Spearman rank test. CONCLUSION: DWI, even if measured in the slice direction only, is able to discriminate MSA-P and both patients with PD and healthy volunteers on the basis of putaminal rADC values. The increased putaminal rADC values in Parkinson variant of multiple system atrophy are likely to reflect ongoing striatal degeneration, whereas most neuropathologic studies reveal intact striatum in PD. Diffusion-weighted imaging may represent a useful diagnostic tool that can provide additional support for a diagnosis of Parkinson variant of multiple system atrophy.

The run-off resistance (ROR) assessed on MR angiograms may serve as a valid scoring system in patients with symptomatic peripheral arterial disease (PAD) and correlates with the ankle-brachial pressure index (ABI).

OBJECTIVE: To investigate the correlation between the hemodynamic parameter ankle-brachial pressure index (ABI) and the run-off resistance (ROR) assessed on MR angiograms (MRA) in patients with peripheral arterial disease (PAD) Fontaine Stage I and II and its potential as reliable reporting system in clinical routine. METHODS: Contrast-enhanced MRA was performed in 321 PAD patients using a 1.5T MR scanner with moving bed technique. The ROR and resting ABI were determined in each patient's leg and correlation analysis was performed using the Pearson test. RESULTS: A significant negative correlation (r = -.513; p<.001) between ROR (mean 11.03±5.42) and resting ABI (mean .81±.26) was identified. An even more pronounced correlation was found in patients younger than median age who had higher ABI values (r = -.608; p<.001). CONCLUSION: The ROR scoring system evaluated in this series correlates better with the ABI than previously published scoring systems and could be suggested as reporting system for routine MRA evaluation.

Risk factor profile for sudden cardiac death during mountain hiking.

Mountain hiking is associated with a death rate of about 4 deaths per 100,000 hikers annually. About 50 % of all fatalities during mountain hiking are sudden cardiac deaths (SCDs). But there are only few data available regarding risk factors and triggers associated with SCD during mountain hiking. Thus, a case-control analysis between persons who died suddenly during mountain hiking and randomly selected controls was carried out. Risk factor profiles of 179 males over the age of 34 who suffered SCD during mountain hiking were compared to those of 537 matched controls. Hikers who died suddenly during mountain hiking were much more likely to have had a prior MI (17% vs. 0.9%; p < 0.001), known coronary artery disease (CAD) without prior MI (17 % vs. 4%; p < 0.001), diabetes (6% vs. 1 %; p < 0.001), hypercholesterolemia (54 % vs. 20%; p < 0.001), and were less engaged in regular mountain sports activities (31% vs. 58%; p < 0.001) compared to hikers from the control group. Based on the reported relationship between traditional risk factors and coronary plaque morphology, acute plaque rupture with thrombus formation and subsequent lethal arrhythmias may be assumed to be a dominant mechanism precipitating SCD during hiking. In contrast, in skiers especially non-occlusive plaques may precipitate ischemia leading to an imbalance between oxygen demand and supply and subsequent lethal arrhythmias. As preventive measures recommended to hikers at risk, adaptation to regular mountain sports activities by an adequate training program and pharmacological interventions, e.g. lipid lowering drugs, aspirin, and beta-blockers, should be considered.

Impact of exercise capacity on myocardial high-energy phosphate metabolism.

31-Phosphorous magnetic resonance spectroscopy (31P MRS) is a unique tool to investigate IN VIVO high-energy phosphates (HEP) in the human heart. We hypothesized that physical capacity may be associated with myocardial HEP status. Healthy, male volunteers (n = 105, mean age 51 +/- 7 years) underwent bicycle ergometry with a stepwise increasing workload to determine maximal working capacity (MWC). Heart rate (HR) and blood pressure (BP) were measured continuously during exercise and 4 minutes of recovery. Further 31-Phosphorous 2-dimensional chemical shift imaging (31P 2D CSI) MRS was performed to assess myocardial HEP metabolism by determining phosphocreatinine to beta-ATP ratios (PCr/b-ATP) using a 1.5 tesla scanner. Volunteers with MWC > 230 Watt had significantly higher PCr/b-ATP ratios than those with MWC < 200 Watt (1.93 +/- 0.36 vs. 1.59 +/- 0.35; p < 0.001). Additionally, those with a recovery systolic (S)BP < 195 mmHg had significantly higher ratios than those with a recovery SBP > 195 mmHg (1.74 +/- 0.3 vs. 1.51 +/- 0.2; p < 0.05). We observed a linear correlation between the PCr/b-ATP ratio and MWC (r = 0.411; p < 0.001) and recovery SBP (r = - 0.290; p < 0.01). After statistical correction for age, these correlations remained significant. In this study, we observed a correlation of parameters of physical fitness determined by bicycle exercise testing and cardiac PCr/b-ATP ratios.

Evaluation of transient apical ballooning with cardiac magnetic resonance imaging and 31-phosphorous magnetic resonance spectroscopy.

Apical ballooning is an increasingly reported transient cardiomyopathy with yet unknown origin. In this study 2 cases of apical ballooning are described in whom we used a combined approach of cardiac magnetic resonance imaging (CMR) and 31-Phosphorous magnetic resonance spectroscopy (31P MRS). Electrocardiogram showed ST abnormalities and cardiac serum markers were mildly elevated, but CAG demonstrated smooth coronary arteries. Cine-CMR revealed severe apical akinesia and significantly decreased ejection fraction. Furthermore we detected reduced myocardial phosphocreatine to beta-ATP (PCr/b-ATP) ratios during the first week of acute disease. After 1 week we observed an improvement of PCr/b-ATP ratios by 68% and 34%, which was associated with an increase in left ventricular function. Our data suggest that 31P MRS might be a valuable tool in the evaluation of apical ballooning, but larger cohorts are needed to improve the understanding of metabolic changes during transient apical ballooning.

How to diagnose MSA early: the role of magnetic resonance imaging.

The clinical differentiation between Parkinson's disease (PD) and multiple system atrophy (MSA) remains a challenge for each neurologist. The use of different magnetic resonance imaging (MRI) techniques including conventional MRI, proton magnetic resonance spectroscopy (MRS), diffusion-weighted imaging (DWI), magnetization transfer imaging (MTI) and MR volumetry (MRV) offer the potential for objective criteria in the differential diagnosis of neurodegenerative parkinsonism. The aim of this article is to review the role of different MRI techniques in the differential diagnosis of PD and MSA.

The impact of peak saturation of the arterial input function on quantitative evaluation of dynamic susceptibility contrast-enhanced MR studies.

PURPOSE: The purpose of this work was to investigate systematic errors in dynamic contrast-enhanced MR perfusion studies due to peak saturation of the arterial input function (AIF) and to introduce a simple correction algorithm. METHOD: Computer simulations were performed to evaluate the influence of AIF peak saturation and to demonstrate the effectiveness of the presented correction algorithm. To compare the computer simulations with real MR data, MR perfusion measurements were performed on volunteers. RESULTS: The computer simulations show that AIF peak saturation leads to a systematic overestimation of cerebral blood volume (CBV) and cerebral blood flow (CBF) values, which was confirmed by comparing the obtained MR data with PET results. With use of an improved calculation algorithm correcting for AIF peak saturation, a significant improvement of the obtained CBV and CBF values could be demonstrated. CONCLUSION: Our results suggest that AIF peak saturation leads to a significant systematic error in the determination of CBV and CBF values and has necessarily to be taken into account for dynamic contrast-enhanced MR perfusion studies.

In vivo magnetic resonance imaging of embryonic neural grafts in a rat model of striatonigral degeneration (multiple system atrophy).

The effects of embryonic neural transplantation in experimental models of neurodegenerative disorders are commonly assessed by behavioral tests and postmortem neurochemical or anatomical analysis. The purpose of the present study was to evaluate embryonic neuronal grafts in a novel rat model of multiple system atrophy (MSA) with the help of in vivo magnetic resonance imaging (MRI) and to correlate imaging with histological parameters. Striatonigral double lesions were created in male Wistar rats by unilateral intrastriatal injection of 3-nitropropionic acid (3-NP). Seven weeks following lesion surgery animals were divided into four transplantation groups receiving either pure mesencephalic, pure striatal, mesencephalic-striatal cografts, or sham grafts. In vivo structural imaging was performed 21 weeks after transplantation using a whole body 1.5 Tesla MR scanner. The imaging protocol comprised T2-weighted TSE and T1-weighted TIR sequences. Immunohistochemistry using DARPP-32 as striatal marker and tyrosinhydroxylase as marker for nigral neurons was performed for correlation analysis of imaging and histological parameters. The sensitivity of graft detection by in vivo MRI was 100%. The graft tissue was clearly demarcated from the remaining striatal tissue in both T2- and T1-weighted sequences. Morphometrically, cross-sectional areas of the grafts and spared intact striatum as defined by immunohistochemistry correlated significantly with measurements obtained by in vivo MRI. In conclusion, we were able to evaluate in vivo both lesion-induced damage and graft size in a 3-NP rat model of MSA using a conventional whole body 1.5 Tesla MRI scanner. Additionally, we obtained an excellent correlation between MRI and histological measurements.

Serial CT volume measurements after endovascular aortic aneurysm repair.

PURPOSE: To evaluate the efficacy of transluminal stent-graft placement in aortic aneurysms using postoperative enhanced spiral computed tomographic (CT) volumetric measurements of the aneurysm sac, the intra-aneurysmal vascular channel (IAVC), the thrombus, and the stent-graft. METHODS: Among 53 patients (45 men; mean age 74 years, range 59-85) who underwent elective endovascular aortic aneurysm repair, 37 patients with 27 abdominal and 10 thoracic aortic aneurysms completed at least a 6-month follow-up that included computerized CT volumetric analysis prior to discharge and at 3, 6, 12, 24, and 36 months. A variety of bifurcated (n = 23) and tube (n = 14) stent-grafts were observed for signs of endoleak and aneurysm enlargement. RESULTS: Mean follow-up was 16 months (range 6-48). Total aneurysm volumes and thrombus volumes decreased, whereas IAVC and stent-graft volumes increased over time. Between the postoperative and 12-month imaging studies, reductions in total aneurysm (p 0.011) and thrombus (p < 0.001) volumes were significant. No statistically significant difference in volume changes for the aneurysm sac (p = 0.555) or the thrombus (p = 0.920) was found when comparing the 24 patients without primary leak to the 12 with primary type-II leak. In all 5 cases with secondary leak, the volume of the aneurysm sac increased after initial shrinkage. CONCLUSIONS: Postoperative CT volumetric analysis is an effective tool for evaluating the outcome of endovascular aortic aneurysm repair. Thrombus volume measurements are more accurate than total aneurysm volumes. In patients in whom contrast agents are contraindicated, volume measurements can also be obtained without the use of contrast.

Diffusion-weighted imaging discriminates progressive supranuclear palsy from PD, but not from the parkinson variant of multiple system atrophy.

BACKGROUND AND OBJECTIVE: The parkinson variant of multiple system atrophy (MSA-P) and progressive supranuclear palsy (PSP) present with atypical parkinsonism, which may be misdiagnosed as PD, particularly in early disease stages. It was previously shown that diffusion-weighted MRI (DWI) is a sensitive tool to discriminate MSA-P from PD based on increased apparent diffusion coefficients (ADCs) in the putamen. In this study DWI was evaluated in 10 patients with PSP compared with 13 patients with PD and 12 with MSA-P. METHODS: Disease was diagnosed according to established diagnostic criteria and groups were matched for age, disease duration, and Hoehn and Yahr "off" stage. Regional ADCs (rADCs) were determined in different brain regions including basal ganglia, gray matter, white matter, substantia nigra, and pons. RESULTS: In patients with PSP compared with those with PD, rADCs were significantly increased in putamen, globus pallidus, and caudate nucleus. Stepwise logistic regression analysis followed by receiver operating characteristics analysis identified an optimal cut-off value for putaminal rADC, discriminating PSP and PD with a sensitivity of 90% and a positive predictive value of 100%. DWI failed to discriminate PSP and MSA-P. CONCLUSIONS: These results show that DWI detects basal ganglia abnormalities in PSP patients within few years of disease onset, discriminating patients with PSP from those with PD, but not from those with MSA-P.