Traumatic optic neuropathy prediction after blunt facial trauma: derivation of a risk score based on facial CT findings at admission.

PURPOSE: To determine the specific facial computed tomographic (CT) findings that can be used to predict traumatic optic neuropathy (TON) in patients with blunt craniofacial trauma and propose a scoring system to identify patients at highest risk of TON. MATERIALS AND METHODS: This study was compliant with HIPAA, and permission was obtained from the institutional review board. Facial CT examination findings in 637 consecutive patients with a history of blunt facial trauma were evaluated retrospectively. The following CT variables were evaluated: midfacial fractures, extraconal hematoma, intraconal hematoma, hematoma along the optic nerve, hematoma along the posterior globe, optic canal fracture, nerve impingement by optic canal fracture fragment, extraconal emphysema, and intraconal emphysema. A prediction model was derived by using regression analysis, followed by receiver operating characteristic analysis to assess the diagnostic performance. To examine the degree of overfitting of the prediction model, a k-fold cross-validation procedure (k = 5) was performed. The ability of the cross-validated model to allow prediction of TON was examined by comparing the mean area under the receiver operating characteristic curve (AUC) from cross-validations with that obtained from the observations used to create the model. RESULTS: The five CT variables with significance as predictors were intraconal hematoma (odds ratio, 12.73; 95% confidence interval [CI]: 5.16, 31.42; P < .001), intraconal emphysema (odds ratio, 5.21; 95% CI: 2.03, 13.36; P = .001), optic canal fracture (odds ratio, 4.45; 95% CI: 1.91, 10.35; P = .001), hematoma along the posterior globe (odds ratio, 0.326; 95% CI: 0.111, 0.958; P = .041), and extraconal hematoma (odds ratio, 2.36; 95% CI: 1.03, 5.41; P = .042). The AUC was 0.818 (95% CI: 0.734, 0.902) for the proposed model based on the observations used to create the model and 0.812 (95% CI: 0.723, 0.9) after cross-validation, excluding substantial overfitting of the model. CONCLUSION: The risk model developed may help radiologists suggest the possibility of TON and prioritize ophthalmology consults. However, future external validation of this prediction model is necessary.

Accuracy of transcranial colour-coded sonography in the diagnosis of anterior cerebral artery vasospasm.

BACKGROUND AND PURPOSE: Transcranial colour-coded sonography (TCCS) has been proven to be a method of high performance in the diagnosis of spasm of the middle cerebral artery (MCA). Relevant data concerning the anterior cerebral artery (ACA) varies amongst studies. The aim of this study was to assess the performance of TCCS in the diagnosis of spasm affecting the ACA. MATERIAL AND METHODS: Ninety-two patients (39 women and 53 men, age 51 ± 12.1 years) were examined using TCCS before cerebral angiography. Of 184 examined ACAs, only 133 arteries could be visualized due to insufficiency of the temporal acoustic window. Therefore, only 15 out of 25 arteries in which vasospasm was diagnosed with angiography (by two neuroradiologists not informed about the sonographic findings) could be included in the analysis. Receiver operating characteristic (ROC) curves were constructed for specific blood flow velocities: peak systolic (PSV), mean (M) and end-diastolic (EDV). The area under the ROC curve was used to measure the overall diagnostic performance of TCCS. RESULTS: The area under the ROC curve for PSV was 0.83, which indicates good performance. The PSV threshold of 98 cm/s corresponded to maximum accuracy and was associated with 71% sensitivity vs. 88% specificity. Average systolic blood flow velocity in the vessels with vasospasm was 129 cm/s, whereas in unaffected vessels it was 76 cm/s. CONCLUSIONS: The accuracy of TCCS in the diagnosis of ACA spasm is relatively high - the value of the area under the ROC amounts to 0.83. PSV performs best and the threshold of 98 cm/s is associated with an optimal trade-off between sensitivity and specificity.

Sickle cell disease and transcranial Doppler imaging: inter-hemispheric differences in blood flow Doppler parameters.

BACKGROUND AND PURPOSE: to establish reference values of interhemispheric differences and ratios of blood flow Doppler parameters in the terminal internal carotid artery, middle cerebral artery, and anterior cerebral artery in children with sickle cell anemia. METHODS: fifty-seven out of 74 recruited children (mean age, 7.8 ± 3.4 years; range limits, 3-14 years), who were free of neurological deficits and intracranial narrowing detectable by MRA and had flow velocities <170 cm/s by conventional transcranial Doppler ultrasound, underwent transcranial color-coded duplex ultrasonography. Reference limits of flow parameters corrected and uncorrected for the angle of insonation were estimated using tolerance intervals, with P=0.90 for all possible data values from 95% of a population. RESULTS: reference limits for left-to-right differences in cm/s in the mean angle-corrected and uncorrected flow velocities were -56 to 53 and -72 to 75 for middle cerebral artery, -49 to 57 and -81 to 91 for anterior cerebral artery, and -55 to 64 and -73 to 78 for terminal internal carotid artery, respectively. Respective reference limits for left-to-right velocity ratios were 0.31 to 1.84 and 0.38 to 1.75 for middle cerebral artery, 0.48 to 2.99 and 0.46 to 2.89 for anterior cerebral artery, and 0.61 to 2.56 and 0.56 to 2.23 for terminal internal carotid artery. CONCLUSIONS: the study provides reference limits of interhemispheric differences and ratios of blood flow Doppler parameters that may be helpful in identification of intracranial arterial narrowing in children with sickle cell disease undergoing ultrasound screening for stroke prevention.

Normal tolerance limits for side-to-side differences in diameters of major lower limbs arteries of 228 healthy subjects.

PURPOSE: To determine reference values and tolerance limits of between-side differences for the calibers of the common femoral artery (CFA), superficial femoral artery (SFA), popliteal artery (PA), dorsalis pedis artery (DPA), and posterior tibial artery (PTA). MATERIALS AND METHODS: Calibers of arteries, defined as the largest distance between internal hyperechogenic lines of the intima-media complex of the arterial wall, were measured during the diastole phase determined from echo-tracking B mode ultrasound scanning and grey-scale ultrasound in 228 healthy volunteers aged 18-81 years (43.1 ± 16.7). RESULTS: The mean, 95% confidence and tolerance limits covering 90% of population for left and right side of each artery were: CFA: 8.1 mm, 7.9-8.3 mm, 6.0-10.3 mm; 8.1 mm, 7.9-8.5 mm, 5.9-10.2 mm; SFA: 6.2 mm, 6.0-6.3 mm, 4.7-7.6 mm; 6.1 mm, 6.0-6.3 mm, 4.7-7.6 mm; PA: 6.1 mm, 6.0-6.2 mm, 4.6-7.6 mm; 6.1 mm, 5.9-6.2 mm, 4.5-7.6 mm; DPA: 2.0 mm, 1.9-2.0 mm, 1.2-2.7 mm; 2.0 mm, 1.9-2.0 mm, 1.2-2.8 mm; PTA: 2.1 mm, 2.0-2.1 mm, 1.4-2.8 mm; 2.1 mm, 2.1-2.2 mm, 1.4-2.8 mm, respectively. Tolerance limits for between-side differences and ratios were: CFA - 0.5-0.7 mm, 0.9-1.1; SFA - 0.5-0.6 mm, 0.9-1.1; PA - 0.5-0.5 mm, 0.9-1.1; DPA -0.4-0.4 mm, 0.8-1.2; PTA - 0.4-0.4 mm, 0.8-1.2. Regression analysis showed weight and age dependency of vessels diameters. There are no differences between men and woman in vessels size, except in DPA's, when body weight and age are taken into account in a regression analysis. CONCLUSIONS: We estimated normal reference tolerance limits of side-to-side differences in diameters of lower limb arteries. The limits can inform an investigator what differences in diameters occur in healthy individuals, and hence can serve as cut-offs in diagnostic and screening strategies.

Sickle cell disease: ratio of blood flow velocity of intracranial to extracranial cerebral arteries--initial experience.

PURPOSE: To establish reference values of the ratios of flow velocity in the middle cerebral artery (V(MCA)) and the terminal portion of the internal carotid artery (V(tICA)) to flow velocity in the extracranial portion of internal carotid artery (V(ICA)) in children with sickle cell disease (SCD). MATERIALS AND METHODS: Institutional ethics committee approval and parental informed consent were obtained for this prospective HIPAA-compliant study. Sixty-eight children (38 female; mean age, 7.7 years +/- 3.3; range, 2-14 years) with HbSS genotype, without neurologic deficits and no history of stroke, were enrolled. Final study population comprised 56 (mean age 8.0 +/- 3.3 years, 26 females) children who underwent magnetic resonance (MR) angiography, which excluded intracranial arterial narrowing, transcranial color-coded duplex ultrasonography (US), and carotid US to determine V(MCA)/V(ICA) and V(tICA)/V(ICA) ratios from angle-corrected and uncorrected velocities. Tolerance interval estimates were used to calculate reference ranges and linear regression was used to quantify associations of Doppler parameters with age adjusted for hemoglobin and hematocrit. RESULTS: Reference ranges in centimeters per second for mean angle-corrected V(MCA) on the left and right sides were 62-198 and 69-153; those for V(tICA) were 30-196 and 36-175; and those for V(ICA) were 18-116 and 15-95, respectively. Reference ranges for mean angle-corrected V(MCA)/V(ICA) ratio on the left and right sides were 1.2-4.0 and 0.4-3.4 and those for V(tICA)/V(IC)(A) ratio were 0.5-2.9 and 0.5-2.7, respectively. V(MCA), V(tICA), and V(tICA)/V(ICA) ratio were not age dependent, contrary to V(ICA) and V(MCA)/V(ICA) ratio, after controlling for hematocrit and hemoglobin. CONCLUSION: The study provides reference limits for V(MCA), V(tICA), V(ICA), and velocity ratios obtained from children with SCD.

Posttreatment recurrence of malignant brain neoplasm: accuracy of relative cerebral blood volume fraction in discriminating low from high malignant histologic volume fraction.

PURPOSE: To determine the accuracy of relative cerebral blood volume (rCBV) fraction for distinguishing high-grade recurrent neoplasm from treatment-related necrosis (TRN) in enhancing masses identified on surveillance magnetic resonance (MR) images following treatment for primary or secondary brain neoplasm. MATERIALS AND METHODS: This institutional review board approved and HIPAA-compliant retrospective study included 30 patients undergoing resection of recurrent enhancing mass appearing after treatment with surgery and radiation, with or without chemotherapy. The enhancing mass volume was manually segmented on three-dimensional T1-weighted images. The rCBV maps were created by using T2-weighted dynamic susceptibility contrast perfusion MR imaging and registered to T1-weighted images, and the fraction of enhancing mass with rCBV above a range of thresholds was calculated. A receiver operating characteristic (ROC) curve was created by calculating sensitivity-specificity pairs at each threshold for rCBV fraction (< or = 20% or > 20%) by using percentage of malignant features at histologic evaluation as the reference criterion. Relationships between rCBV and probability of recurrence were estimated by using logistic regression analysis. RESULTS: ROC analysis showed excellent discriminating accuracy of rCBV fraction (area under the ROC curve, 0.97 +/- 0.03 [standard error]) and high efficiency (93%) with an rCBV threshold of 1.8 times that of normal-appearing white matter. Logistic regression analysis showed that a unit increase of rCBV is associated with a 254-fold increase (95% confidence interval: 43, 1504, P < .001) of the odds that enhanced tissue is recurrence, adjusting for age, treatment, volume of enhancing tissue, and time to suspected recurrence. CONCLUSION: The fraction of malignant histologic features in enhancing masses recurring after treatment for brain neoplasms can be predicted by using the rCBV fraction, with improved differentiation between recurrent neoplasm and TRN.

Middle cerebral artery vasospasm: transcranial color-coded duplex sonography versus conventional nonimaging transcranial Doppler sonography.

OBJECTIVE: To prospectively compare accuracies of transcranial color-coded duplex sonography (TCCS) and transcranial Doppler sonography (TCD) in the diagnosis of middle cerebral artery (MCA) vasospasm. DESIGN: Prospective blinded head-to-head comparison TCD and TCCS methods using digital subtraction angiography (DSA) as the reference standard. SETTING: Department of Radiology in a tertiary university health center in a metropolitan area. PATIENTS: Eighty-one consecutive patients (mean age, 53.9 +/- 13.9 years; 48 women). The indication for DSA was subarachnoid hemorrhage in 71 patients (87.6%), stroke or transient ischemic attack in five patients (6.2%), and other reasons in five patients (6.2%). INTERVENTIONS: The MCA was graded as normal, narrowed <50%, and >50% using DSA. The accuracy of ultrasound methods was estimated by total area (Az) under receiver operator characteristic curve. To compare sensitivities of ultrasound methods, McNemar's test was used with mean velocity thresholds of 120 cm/sec for the detection of less advanced, and 200 cm/sec for the more advanced MCA narrowing. MEASUREMENTS AND MAIN RESULTS: Angiographic MCA narrowing 50% in 10 of 135 arteries. Accuracy of TCCS was insignificantly higher than that of TCD in the detection of 50% narrowing, total Az for mean velocity being 0.83 +/- 0.05, 0.77 +/- 0.05, and 0.95 +/- 0.02, 0.86 +/- 0.08, respectively. Sensitivity of TCCS at commonly used threshold of 120 cm/sec for less advanced MCA spasm was significantly better than that of TCD at similar specificity, 55% vs. 39%, p = 0.038, whereas at a threshold of 200 cm/sec used for more advanced spasm, sensitivities and specificities of both methods were not different. CONCLUSION: The accuracy of TCCS and TCD is similar, but TCCS is more sensitive than TCD in the detection of MCA spasm. Sensitivity of both techniques in the detection of mild and more advanced spasm using 120 cm/sec and 200 cm/sec thresholds, respectively, is poor; however, a larger sample is required to increase precision of our sensitivity estimates.

Magnetic resonance perfusion-weighted imaging defines angiogenic subtypes of oligodendroglioma according to 1p19q and EGFR status.

1p19q LOH has been shown to predict radio- and chemosensitivity and prolonged survival in oligodendrogliomas (OLs). We have recently shown that magnetic resonance perfusion-weighted imaging (MR-PWI) may be useful in predicting the histopathological grade or cytogenetic type of oligodendroglial neoplasms. MR-PWI allows noninvasive determination of relative tumor blood volume (rTBV), which may reflect the degree of neoplastic angiogenesis and metabolism. The present study was aimed to correlate rTBV to the angiogenic markers and EGFR expression in oligodendroglial tumors with 1p/19q LOH or 1p LOH (Group 1) and 1p19q intact alleles or 19q LOH (Group 2), respectively. In WHO grade II neoplasms, Group 1 showed significantly greater rTBV than Group 2 (P = 0.013). However, the differences between Group 1 and Group 2 were not significant in grade III tumors. Probe-based real-time RT-PCR analyses showed that 12% of Group 2 high-grade tumors with intact 1p19q exhibited dramatic EGFR overexpression (designated EGFR-high). Grade III neoplasms showed a significantly higher rTBV than grade II neoplasms. Group 1 tumors showed significantly higher rTBV than Group 2 tumors, independent of the EGFR-high subtype. Real-time RT-PCR analyses showed increased expression of VEGF, CD31 and CD105 in Group 1 tumors as compared to Group 2 tumors, excluding the EGFR-high subtype. Multivariable linear regression analysis showed a significant association of rTBV with 1p19q LOH, and expression of EGFR and VEGF. Therefore, the combined use of extensive molecular profiling and advanced MR imaging modalities may improve the accuracy of tumor grading, provide prognostic information, and has the potential to influence treatment decisions.

Carotid calcium scoring may correlate in males with the traditional Framingham epidemiologic risk variables for stroke.

BACKGROUND: Coronary calcium scoring is gaining wider use as a marker of coronary heart disease. Our hypothesis is that carotid calcium scoring correlates with the10-year stroke risk. METHOD: Unenhanced cervical spine CT for trauma patients 50 years and older over a 6-month period were retrospectively collected and subsequently processed to generate calcium scores. The medical records were reviewed, and risk factors necessary for estimation of the 10-year stroke risk were recorded and the 10-year stroke risk was correlated with the calcium score. RESULTS: The standard calcium scoring software program (Calcium Scoring CT, Siemens, Erlangen, Germany) used for the coronary artery scoring was able to process the cervical spine CT. The calcium score for the ICA&B correlated with the 10-year stroke risk for males with a Spearman rank correlation value of 0.612. Correlation was not evident for females or the group as a whole. CONCLUSION: The calcium score of the ICA&B correlates with the10-year stroke risk for males in this small cohort and may prove to be a marker for cerebrovascular events.

Normal reference values of ratios of blood flow velocities in internal carotid artery to those in common carotid artery using Doppler sonography.

PURPOSE: The ratios of of blood flow velocities in the internal carotid artery (ICA) to those in the common carotid artery (CCA) (V(ICA)/V(CCA)) are used to identify patients with critical ICA narrowing, but their normal reference values have not been established. We provide reference data for the V(ICA)/V(CCA) ratios for the peak systolic velocity (PSV), mean velocity (MV), and end-diastolic velocity (EDV) measured in a large group of healthy subjects. METHODS: We examined 343 healthy subjects with color duplex sonography. They were divided into 3 age groups: group I, <40 years; group II, 40-60 years; group III, >60 years. RESULTS: The values of V(ICA)/V(CCA) ratio for the PSV were as follows [mean (upper and lower reference values)]. In women, group I: 0.81 (0.48-1.14), group II: 0.88 (0.36-1.40), group III: 0.9 (0.36-1.40). In men, group I: 0.65 (0.32-0.98), group II: 0.72 (0.39-1.05), group III: 0.91 (0.27-1.56). The V(ICA)/V(CCA) ratio for PSV increased with age only in men and its values were significantly higher in women than in men in the group I and group II age groups. CONCLUSION: This study provides normal reference values for the V(ICA)/V(CCA) ratios for PSV and shows that the ratio varies with age and sex. The upper reference limit for the ratio can serve as an aid in the more specific identification of patients with minor or mild ICA narrowing.

Age and sex dependency of blood flow velocity in the internal carotid artery.

BACKGROUND AND PURPOSE: Colour-coded duplex sonography is a handy, cost-effective method of screening for stroke-endangered subjects through reliable measurement of blood flow velocity within the internal carotid artery (ICA). The purpose of this investigation was to analyze the effect of age and sex on blood flow velocity and side-to-side differences in the ICAs. MATERIAL AND METHODS: Three hundred forty-three healthy volunteers (215 women and 128 men) were divided into 3 age groups: group I < 40 years, group II 41-60 years, and group III > 60 years. Blood flow velocities in the ICA were examined with a Toshiba scanner Aplio SSA 770A, endowed with a linear 7.5 MHz probe. RESULTS: Blood flow velocities in the ICA (mean +/- SD, cm/s) were as follows. In men (group I/group II/group III): peak systolic (PSV) - 64.0 +/- 18.2/58.6 +/- 14.4/60.3 +/- 18.2, mean (MV) - 36.0 +/- 8.3/34.1 +/- 8.5/33.8 +/- 9.3, end diastolic (EDV) - 24.7 +/- 6.2/22.9 +/- 6.8/20.1 +/- 5.5. In women (group I/group II/group III): PSV - 77.2 +/- 16.9/66.5 +/- 20.4/52.5 +/- 16.7, MV - 45.4 +/- 9.5/42.2 +/- 12.2/31.0 +/- 10.3, EDV - 30.8 +/- 7.3/28.1 +/- 9.1/18.7 +/- 6.9. Blood flow velocities were stable up to the age of 40-45 years and during this age span were significantly higher in women than in men. After that age, blood flow velocities continued to decrease in both ICAs in women whereas in men this decrease was less steep and pertained mainly to the right ICA. CONCLUSION: The pattern of blood flow in the ICA changes with age in a different way in men than in women.

Lack of choline elevation on proton magnetic resonance spectroscopy in grade I-III gliomas.

Elevated levels of choline are generally emphasized as marker of increased cellularity and cell membrane turnover in gliomas. In this study, we investigated the incidence rate of lack of choline/creatine and choline/water elevation in a population of grade I-III gliomas. A cohort of 41 patients with histopathologically confirmed gliomas underwent multi-voxel proton magnetic resonance spectroscopy on a 3 T magnetic resonance system prior to treatment. Peak areas for choline and myoinositol were measured from all voxels that exhibited hyperintensity on fluid-attenuated inversion recovery images and were normalized to creatine and unsuppressed water from each voxel. The average metabolite/creatine and metabolite/water ratios from these voxels were then computed. Similarly, average metabolite ratios were computed from normal brain parenchyma. Gliomas were considered for lack of choline elevation when choline/creatine and choline/water ratios from neoplastic regions were less than those from normal brain parenchyma regions. Six of 41 (14.6%) grade I-III gliomas showed lack of elevation for choline/creatine and choline/water ratios compared to normal brain parenchyma. Four of these six gliomas also demonstrated elevated levels of myoinositol/creatine ratio. All other gliomas (n = 35) had elevated choline levels from neoplastic regions relative to normal parenchyma. The sensitivity of choline/creatine or choline/water in determining a grade I-III glioma was 85.4%. These findings suggest that a lack of choline/creatine or choline/water elevation may be seen in some gliomas and low choline levels should not prevent us from considering the possibility of a grade I-III glioma.

Discrimination of capsular stage brain abscesses from necrotic or cystic neoplasms using diffusion-weighted magnetic resonance imaging.

OBJECT: The authors' aim was to assess the ability of apparent diffusion coefficient (ADC) ratios in distinguishing brain abscesses from cystic or necrotic neoplasms. METHODS: Fifty-three patients with rim-enhancing masses in the brain observed on T1-weighted MR images were included: 26 had abscesses (14 bacterial, six nonbacterial, and six of unknown origin), 11 had glioblastoma multiforme, and 16 had rim-enhancing metastasis. The ADC values, derived from diffusion-weighted imaging, were measured in the most homogeneous portion of the cystic component of the mass. The ADC ratios were calculated by dividing the ADC values from the nonenhancing cystic portion of the mass by the ADC values from contralateral normal-appearing white matter. Lesions were further differentiated based on presence, absence, or incompleteness of a T2 hypointensity rim. The mean (+/- standard deviation) ADC ratios were significantly higher in neoplasms than in abscesses (2.45 +/- 0.91 compared with 1.12 +/- 0:53, p < 0.01). The accuracy of ADC ratios in discriminating abscesses from neoplasms, determined by the area under the receiver operating characteristic curve (Az), was high: 0.91 +/- 0.04 (mean +/- standard error of the mean [SEM]). The threshold of 1.7 was associated with highest efficiency (87%) in discriminating abscesses from neoplasms. If only bacterial abscesses were analyzed compared with neoplasms, the Az increased to 0.96 +/- 0.03 (SEM). Using ADC ratios and T1 rim characteristics, 50 of 53 lesions were correctly classified (efficiency 94.3%). CONCLUSIONS: The accuracy of ADC ratios in discriminating brain abscesses from cystic or necrotic neoplasms is very high and can be further improved using T2 rim characteristics.

Prediction of oligodendroglial tumor subtype and grade using perfusion weighted magnetic resonance imaging.

OBJECT: Treatment of patients with oligodendrogliomas relies on histopathological grade and characteristic cytogenetic deletions of 1p and 19q, shown to predict radio- and chemosensitivity and prolonged survival. Perfusion weighted magnetic resonance (MR) imaging allows for noninvasive determination of relative tumor blood volume (rTBV) and has been used to predict the grade of astrocytic neoplasms. The aim of this study was to use perfusion weighted MR imaging to predict tumor grade and cytogenetic profile in oligodendroglial neoplasms. METHODS: Thirty patients with oligodendroglial neoplasms who underwent preoperative perfusion MR imaging were retrospectively identified. Tumors were classified by histopathological grade and stratified into two cytogenetic groups: 1p or 1p and 19q loss of heterozygosity (LOH) (Group 1), and 19q LOH only on intact alleles (Group 2). Tumor blood volume was calculated in relation to contralateral white matter. Multivariate logistic regression analysis was used to develop predictive models of cytogenetic profile and tumor grade. RESULTS: In World Health Organization Grade II neoplasms, the rTBV was significantly greater (p < 0.05) in Group 1 (mean 2.44, range 0.96-3.28; seven patients) compared with Group 2 (mean 1.69, range 1.27-2.08; seven patients). In Grade III neoplasms, the differences between Group 1 (mean 3.38, range 1.59-6.26; four patients) and Group 2 (mean 2.83, range 1.81-3.76; 12 patients) were not significant. The rTBV was significantly greater (p < 0.05) in Grade III neoplasms (mean 2.97, range 1.59-6.26; 16 patients) compared with Grade II neoplasms (mean 2.07, range 0.96-3.28; 14 patients). The models integrating rTBV with cytogenetic profile and grade showed prediction accuracies of 68 and 73%, respectively. CONCLUSIONS: Oligodendroglial classification models derived from advanced imaging will improve the accuracy of tumor grading, provide prognostic information, and have potential to influence treatment decisions.

Suitability of temporal bone acoustic window: conventional TCD versus transcranial color-coded duplex sonography.

PURPOSE AND BACKGROUND: To determine whether the proportion of patients with suitable temporal bone acoustic windows is different for conventional transcranial Doppler sonography (TCD) and transcranial color-coded duplex sonography (TCCS), based on a head-to-head comparison in the same population of patients. SUBJECTS AND METHODS: Ninety patients, age 22-88 years (mean 57.1 +/- 11.7 years), 46 women and 44 men, 66 Caucasian, 19 African-American, and five Hispanic, underwent routine conventional TCD and the TCCS examination close in time to each other. Suitability of temporal bone acoustic window was defined by ability to insonate the middle and posterior and/or anterior cerebral arteries, while partial suitability was defined by ability to detect the posterior cerebral artery but not the middle cerebral artery. To compare proportions of suitable temporal bone windows for both sonographic methods, exact sign test by Liddell was used. RESULTS: Bilateral absence of temporal bone acoustic window was reported in six patients when studied with both conventional TCD and TCCS, whereas at least unilateral absence was reported in 10 patients. Partial, at least unilateral, suitability was reported in 11 patients with conventional TCD, and in 7 with TCCS. All differences in proportions were not significant (two-sided P>0.05). CONCLUSIONS: This study suggests that success rate of insonating the intracranial vessels through the temporal bone acoustic window is the same for conventional TCD and imaging TCCS.

Cerebral hemodynamics and investigations of cerebral blood flow regulation.

To maintain adequate cerebral blood flow despite frequent changes in systemic arterial blood pressure and to constantly adjust blood supply to the current metabolic demand dictated by neuronal electrical activity, brain developed a myriad of mechanisms. These are designed to protect central nervous system from fatal consequences of hypoxia and energy deficit and are collectively called "cerebral autoregulation". Despite years of research mechanisms responsible for regulation of CBF functioning under physiologic and pathologic conditions are still not clear. When these mechanisms are damaged or exhausted, patients life is in danger, as even slight, negligible under normal conditions, systemic hemodynamic disturbances might lead to cerebral infarct. Even perfect imaging of the irreversible brain damage with MR for the particular patient is too late action. Thus, detection of cerebral blood flow disturbances and impaired autoregulation, which are known to be associated with high risk of stroke, are extremely important in clinical practice. Several methods have been developed to quantify this process and thus evaluate risk of cerebral ischemia and guide therapeutic process. This review focuses on current knowledge on physiology of regulation of cerebral blood flow, mechanisms responsible for brain damage resulted from cerebral ischemia and reviews noninvasive diagnostic tests to assess cerebral autoregulation.

[Neuroprotective effect of oestrogen on the central nervous system]. / Neuroprotekcyjne oddzialywanie estrogenów na struktury osrodkowego ukladu nerwowego.

It has been demonstrated that some regions of the brain are endowed in oestrogen receptors alpha and beta. Moreover, some neuroprotectants were found to be differently effective in both sexes. Such findings have naturally aroused interest in possible neuroprotective effects of female sex hormones. Today is apparent that the brain is a target organ for oestrogen and both neuronal activity and regional cerebral blood flow can be modulated by this hormone. By stimulating formation of new synaptic connections, oestrogen can also increase brain plasticity, cognitive functions and memory. It has been demonstrated that oestrogen increases regional and global cerebral blood flow by decreasing cerebral vascular impedance and by favourable modification of rheological properties of blood (attenuation of platelet aggregation and adhesion, diminution of leukocyte's contact with the vascular wall, etc.). Oestrogen also mitigates inflammatory and immunological reactions and protects vascular endothelium by reducing apoptosis of the endothelial cells. It also stimulates secretion of different grow factors like BDNF, FGF, NGF, or IGF. Foremost, by its complex interactions with different harmful biochemical reactions occuring during brain ischemia, oestrogen in a great degree prevents formation of free oxygen radicals. Taking the above into consideration and remembering neuroprotective role of endogenous oestrogen, some authors suggest the use of exogenous oestrogen as a therapeutical neuroprotector.

Cross-sectional area of the femoral vein varies with leg position and distance from the inguinal ligament.

PURPOSE: The risk of complications associated with femoral venous catheterization could be potentially reduced if the procedure was performed at the location where the cross-sectional area (CSA) of the vessel is the largest. The diameter of the femoral vein depends on leg position as well as the distance from the inguinal ligament. We determined the CSA of the right femoral vein in three different leg positions at two distances from the inguinal ligament. SUBJECTS AND METHODS: Informed consent was given by 205 healthy volunteers aged 19-39 years, mean: 23±3 years (108 women, 97 men). Ultrasonographic examinations were performed using a linear 14-MHz transducer with CSA measurements in three leg positions: abduction, abduction+external rotation, abduction+external rotation+90° knee flexion/frog-leg position; at levels 20 mm caudally to the inguinal ligament, and 20 mm caudally to the inguinal crease. RESULTS: We found significant differences in mean values of CSA in three leg positions regardless of the measurement level. The largest mean CSA (114 mm2±35 mm2) was found at the proximal level in the frog-leg position. There was a significant association of the CSA with sex and height. The CSA in males was greater than in females in all leg positions at the level of 20 mm caudally to the inguinal crease, while 20 mm caudally to the inguinal ligament the CSA was larger in females. The CSA of 25% of the femoral vein was smaller than 45.0 mm2 at the proximal level, and 31.5 mm2 at the distal level, which refers to diameters of 5.3 mm, and 4.5 mm, respectively. CONCLUSIONS: The cross-sectional area of the femoral vein is the largest in the frog-leg position, and depends on gender.

Brain morphometric analysis predicts decline of intelligence quotient in children with sickle cell disease: A preliminary study.

PURPOSE: For children with sickle cell disease (SCD) and at low risk category of stroke, we aim to build a predictive model to differentiate those with decline of intelligence-quotient (IQ) from counterparts without decline, based on structural magnetic-resonance (MR) imaging volumetric analysis. MATERIALS AND METHODS: This preliminary prospective cohort study included 25 children with SCD, homozygous for hemoglobin S, with no history of stroke and transcranial Doppler mean velocities below 170cm/s at baseline. We administered the Kaufman Brief Intelligence Test (K-BIT) to each child at yearly intervals for 2-4 years. Each child underwent MR examination within 30 days of the baseline K-BIT evaluation date. We calculated K-BIT change rates, and used rate of change in K-BIT to classify children into two groups: a decline group and a non-decline group. We then generated predictive models to predict K-BIT decline/non-decline based on regional gray-matter (GM) volumes computed from structural MR images. RESULTS: We identified six structures (the left median cingulate gyrus, the right middle occipital gyrus, the left inferior occipital gyrus, the right fusiform gyrus, the right middle temporal gyrus, the right inferior temporal gyrus) that, when assessed for volume at baseline, are jointly predictive of whether a child would suffer subsequent K-BIT decline. Based on these six regional GM volumes and the baseline K-BIT, we built a prognostic model using the K* algorithm. The accuracy, sensitivity and specificity were 0.84, 0.78 and 0.86, respectively. CONCLUSIONS: GM volumetric analysis predicts subsequent IQ decline for children with SCD.

Carotid artery diameter in men and women and the relation to body and neck size.

BACKGROUND AND PURPOSE: To explore relationships among gender, body size, neck size, and the diameters of the common carotid artery (CCA) and internal carotid artery (ICA). METHODS: Using multivariate regression, the best predictors of sonographic diameters of CCA and ICA were determined based on age, height, weight, body mass index, body surface area, neck circumference, neck length, and blood pressure. RESULTS: Measurements were obtained in 500 consecutive patients (age 52+/-15 years; 61% women). Mean diameters of ICA (4.66+/-0.78 mm) and CCA (6.10+/-0.80 mm) in women were significantly smaller than in men: 5.11+/-0.87 mm and 6.52+/-0.98 mm, respectively. Sex significantly influenced the diameters after controlling for body size, neck size, age, and blood pressure. CONCLUSIONS: Carotid arteries are smaller in women even after adjusting for body and neck size, age, and blood pressure.