Accuracy of computed tomography angiography in the detection of pulmonary embolism in patients with high body weight.

BACKGROUND: The accuracy of CT pulmonary angiography (CTPA) in detecting or excluding pulmonary embolism has not yet been assessed in patients with high body weight (BW). METHODS: This retrospective study involved CTPAs of 114 patients weighing 75-99 kg and those of 123 consecutive patients weighing 100-150 kg. Three independent blinded radiologists analyzed all examinations in randomized order. Readers' data on pulmonary emboli were compared with a composite reference standard, comprising clinical probability, reference CTPA result, additional imaging when performed and 90-day follow-up. Results in both BW groups and in two body mass index (BMI) groups (BMI <30 kg/m(2) and BMI ≥ 30 kg/m(2), i.e., non-obese and obese patients) were compared. RESULTS: The prevalence of pulmonary embolism was not significantly different in the BW groups (P=1.0). The reference CTPA result was positive in 23 of 114 patients in the 75-99 kg group and in 25 of 123 patients in the ≥ 100 kg group, respectively (odds ratio, 0.991; 95% confidence interval, 0.501 to 1.957; P=1.0). No pulmonary embolism-related death or venous thromboembolism occurred during follow-up. The mean accuracy of three readers was 91.5% in the 75-99 kg group and 89.9% in the ≥ 100 kg group (odds ratio, 1.207; 95% confidence interval, 0.451 to 3.255; P=0.495), and 89.9% in non-obese patients and 91.2% in obese patients (odds ratio, 0.853; 95% confidence interval, 0.317 to 2.319; P=0.816). CONCLUSION: The diagnostic accuracy of CTPA in patients weighing 75-99 kg or 100-150 kg proved not to be significantly different.

Tumor-specific localization of self-assembled nanoparticle PET/MR modalities.

AIM: The aim of this work was to synthesize and study in vitro and in vivo nanocarriers used as magnetic resonance imaging (MRI) contrast agents that accumulate in tumor cells specifically overexpressing folate receptors. MATERIALS AND METHODS: Nanoparticles were prepared by self-assembly of poly-γ-glutamic acid and chitosan biopolymers and were complexed with gadolinium ions. Folic acid served as a targeting molecule. Rat hepatocellular carcinoma (HeDe) cells overexpressing folate receptors were used as a model system. For in vivo experiments, HeDe cells were transplanted under the renal capsule of F344 rats. RESULTS: In vitro results showed the significant internalization of nanoparticles into HeDe cells. MRI measurements revealed that targeting nanocarriers accumulated in tumors. The MRI/PET fusion images resulted in the exact localization of tumors. CONCLUSION: The nanocarrier provides a suitable means for the early diagnosis of tumors based on their overexpression of folate receptors.

Cortical spreading edema in persistent visual migraine aura.

We present imaging evidence of the spreading of cortical edema with reversibly restricted water diffusion from the left occipital to the temporoparietal cortex in persistent visual migraine aura in a 58-year-old man. The right-sided visual field defect lasting for 15 days was associated with discoupling of glucose metabolism and blood flow and the decreased apparent diffusion coefficient also suggested cytotoxic edema. At 8 weeks no signs were present, and magnetic resonance imaging became normal; therefore, long-lasting restricted cortical water diffusion, even if coupled with hypometabolism and edema, can be reversible in persistent visual migraine aura.

Pattern of increased cerebral FDG uptake in Down syndrome patients.

Resting cerebral glucose metabolism was assessed by 18[F]-fluorodeoxyglucose in 11 Down syndrome patients. Standardized uptake values were determined on a pixel-by-pixel basis from the measured tissue-activity data. The results revealed a mean overall 18[F]-fluorodeoxyglucose uptake in the Down syndrome patients close to that observed in the control group, consisting of children and young adults. However, the standard deviation of the standardized uptake values was much higher in the Down syndrome group in almost all voxels relating to the gray matter. The statistical parametric mapping method was applied to compare the cerebral 18[F]-fluorodeoxyglucose accumulation patterns of the Down syndrome and control groups. Six regions (clusters) were found for which the glucose uptake was higher in the Down syndrome patients than in the control group. The anatomic localization of these clusters was based on magnetic resonance investigations and a brain-atlas technique. The localization of the identified clusters with an increased glucose metabolism in the Down syndrome patients suggests that these subjects have an enhanced resting neuronal activity in cortical areas involved in reasoning, cognition, and speech as compared with normal subjects.

[Primary cerebral angiitis: a case history and literature review of its diagnosis]. / Primer cerebralis angiitis: esetismertetés és irodalmi összefoglalás.

The authors present a case history of primary cerebral angiitis with four years of follow-up. The early diagnosis was based on typical clinical symptoms, brain MRI, intracerebral MRA and histology of sural nerve biopsy. Electroneurography suggested peripheral involvement, although the patient did not have clinical signs of peripheral neuropathy. Glucocorticoid and immunosuppressive treatment resulted in remission. The diagnostic difficulties of primary cerebral vasculitis are also summarized in the discussion.

Image quality of the temporal bone window examined by transcranial Doppler sonography and correlation with postmortem computed tomography measurements.

BACKGROUND AND PURPOSE: The major limitation of native transcranial colour-coded duplex sonography (TCCS) in older stroke patients is the relatively frequent occurrence of an insufficient temporal window. Our goal was to investigate the relationship between the in vivo Doppler ultrasound image quality of the temporal bone, and computed tomography (CT)-determined thickness, density, and homogeneity of cadaver temporal bone. METHODS: Thirty-three moribund neurological patients who eventually died were examined by TCCS using the transtemporal approach. The sonographer categorized the quality of the TCCS image (excellent, intermediate, and poor). During autopsy, a rectangular sample of the temporal squama was removed, which corresponded to the area of the in vivo acoustic window. The thickness of the whole temporal bone, cortical, and cancellous (= diploe) bone as well as the density and homogeneity were determined by high-resolution CT. RESULTS: Thirty-seven temporal bones were obtained. The quality of the acoustic window was classified as excellent in 13, intermediate in 6 and poor in 18 cases. A significant correlation between the complete bone thickness, as well as between the absolute thickness of the diploe and the quality of the acoustic window was found: the thinner the bone/diploe, the better the colour Doppler signal. The thickness of the cortical plates and the homogeneity of the bones were identical in the three image quality categories. CONCLUSION: The transtemporal TCCS image quality depends mainly on the thickness of the cancellous component of the temporal bone.

MRI findings in central nervous system systemic lupus erythematosus are associated with immunoserological parameters and hypertension.

Involvement of the brain is one of the most important complications of systemic lupus erythematosus (SLE). To investigate the correlation between abnormal cranial MRI findings and age, duration of SLE, neuropsychiatric (NP) manifestations, hypertensive status, and the presence of antiphospholipid antibodies (PA) in patients with SLE we evaluated the MRI results of 81 SLE patients in nine NP clinical subgroups.Immunoserological status was described by the presence of lupus anticoagulant (LA), and anticardiolipin antibodies (aCL). The MRI findings were categorized as normal [41], cerebral atrophy [15], small subcortical hyperintensity [7], and infarct larger than 10mm [18]. Mean age differed among the clinical subgroups (ANOVA, p = 0.002), whereas there was no age difference among the subgroups based on MRI and immunoserological results. Patients with hypertension (33/81) were a mean of 6 years older at the time of examination (p = 0.033) and had stroke more frequently, than normotensive ones (p = 0.0015). MRI abnormalities were more frequent in patients with LA positivity (p < 0.01) than in those without these antibodies, and in the hypertensive than in the normotensive subgroup (p = 0.00041). The presence of PA was associated with abnormal MRI even after controlling for the effect of age and hypertensive status (p = 0.011). In our study the MRI findings in central nervous system SLE were independent of the age of patients and the age at the diagnosis of SLE, and were not influenced by the duration of SLE; however, they were associated with immunoserological parameters and hypertension.

[Cerebral glucose metabolism in Down syndrome using positron emission tomography]. / Az agyi glükózanyagcsere vizsgálata Down-kórban pozitronemissziós tomográfiával.

Resting cerebral glucose metabolism was assessed by PET using FDG in eleven Down syndrome (DS) patients. Standardized uptake values (SUV) were determined on a pixel by pixel basis from the measured tissue FDG-activity data. The results showed that the mean value of the global FDG-uptake in the DS patients was not significantly different from the one obtained in the control group consisting of children and young adults. The standard deviation of SUV, however, was much higher in the DS group in almost all regions. The statistical parametric mapping (SPM) method was applied to compare the relative cerebral FDG accumulation pattern of the populations. Six regions (clusters) were found in which the glucose-uptake was higher in the DS patients than in the control group. The anatomical localization of these clusters was based on MRI investigations and brain-atlas technique.

[Effect of flumazenil on the regional cerebral blood flow measured by [15O]-butanol PET scan and transcranial Doppler ultrasonography]. / Flumazenil hatása a regionális agyi perfusióra [15O]-butanol-PET- és transcranialis Doppler-UH-vizsgálatok alapján.

The authors investigated the role of the cBZD/GABA-A receptor-complex in the regulation of rCBF by simultaneously applying [15O]-butanol-PET and TCD in therapy-resistant TLE patients. It is known that the density of the cBZD/GABA-A-receptors is reduced in the epileptogenic area of the temporal lobe, but there are no data available about the impact of this phenomenon on rCBF. FMZ is a well-known BZD-receptor antagonist which can be used to inhibit the effect mediated by cBZD/GABA-A-receptors, offering a way to study the contribution of these receptors in the determination of rCBF. The authors examined the possible correlation between the rCBF values obtained by PET and the blood flow speed readings measured by TCD in MCAs. The results show that FMZ does not cause any change in rCBF on the side of the epileptogenic focus but it significantly raises rCBF (p < 0.001) in the intact brain tissue on the other side. The TCD measurements showed no significant differences between the blood flow in the MCAs supplying the affected and the contralateral lobe.