Showing papers on "Perfusion scanning published in 2008"
TL;DR: Dynamic susceptibility-weighted contrast material-enhanced perfusion MR imaging can be used to predict median time to progression in patients with gliomas, independent of pathologic findings.
Abstract: Purpose: To retrospectively determine whether relative cerebral blood volume (CBV) measurements can be used to predict clinical outcome in patients with high-grade gliomas (HGGs) and low-grade gliomas (LGGs) and specifically whether patients who have gliomas with a high initial relative CBV have more rapid progression than those who have gliomas with a low relative CBV. Materials and Methods: Approval for this retrospective HIPAA-compliant study was obtained from the Institutional Board of Research Associates, with waiver of informed consent. One hundred eighty-nine patients (122 male and 67 female patients; median age, 43 years; range, 4–80 years) were examined with dynamic susceptibility-weighted contrast material–enhanced perfusion magnetic resonance (MR) imaging and were followed up clinically with MR imaging (median follow-up, 334 days). Log-rank tests were used to evaluate the association between relative CBV and time to progression by using Kaplan-Meier curves. Binary logistic regression was used t...
482 citations
TL;DR: Although increasing CAC content is generally predictive of a higher likelihood of ischemia, its absence does not completely eliminate the possibility of flow-limiting coronary artery disease.
Abstract: Background— Although the value of coronary artery calcium (CAC) for atherosclerosis screening is gaining acceptance, its efficacy in predicting flow-limiting coronary artery disease remains controversial, and its incremental prognostic value over myocardial perfusion is not well established. Methods and Results— We evaluated 695 consecutive intermediate-risk patients undergoing combined rest-stress rubidium 82 positron emission tomography (PET) perfusion imaging and CAC scoring on a hybrid PET-computed tomography (CT) scanner. The frequency of abnormal scans among patients with a CAC score ≥400 was higher than that in patients with a CAC score of 1 to 399 (48.5% versus 21.7%, P<0.001). Multivariate logistic regression supported the concept of a threshold CAC score ≥400 governing this relationship (odds ratio 2.91, P<0.001); however, the frequency of ischemia among patients with no CAC was 16.0%, and its absence only afforded a negative predictive value of 84.0%. Risk-adjusted survival analysis demonstrate...
360 citations
TL;DR: Dual energy CT perfusion imaging is able to display pulmonary perfusion defects with good agreement to scintigraphic findings and DECT can provide a pulmonary CT angiogram, high-resolution morphology of the lung parenchyma and perfusion information in one single exam.
270 citations
TL;DR: Simultaneous information on the presence of endoluminal thrombus and lung perfusion impairment can be obtained with dual-energy computed tomography.
231 citations
TL;DR: There were significant differences for all perfusion MR imaging-estimated parameters except F(p) and F(t).
Abstract: Institutional review board approval and informed consent were obtained for this HIPAA–compliant study. The purpose of this study was to prospectively evaluate sensitivity and specificity of various estimated perfusion parameters at three-dimensional (3D) perfusion magnetic resonance (MR) imaging of the liver in the diagnosis of advanced liver fibrosis (stage ≥ 3), with histologic analysis, liver function tests, or MR imaging as the reference standard. Whole-liver 3D perfusion MR imaging was performed in 27 patients (17 men, 10 women; mean age, 55 years) after dynamic injection of 8–10 mL of gadopentetate dimeglumine. The following estimated perfusion parameters were measured with a dual-input single-compartment model: absolute arterial blood flow (Fa), absolute portal venous blood flow (Fp), absolute total liver blood flow (Ft) (Ft = Fa + Fp), arterial fraction (ART), portal venous fraction (PV), distribution volume (DV), and mean transit time (MTT) of gadopentetate dimeglumine. Patients were assigned to ...
223 citations
TL;DR: The findings of this study suggest that perfusion MR imaging may be used to differentiate recurrent intra-axial metastatic tumor from gamma knife−induced radiation necrosis.
Abstract: BACKGROUND AND PURPOSE: MR image−guided gamma knife radiosurgery is often used to treat intra-axial metastatic neoplasms. Following treatment, it is often difficult to determine whether a progressively enhancing lesion is due to metastatic tumor recurrence or radiation necrosis. The purpose of our study was to determine whether relative cerebral blood volume (rCBV), relative peak height (rPH), and percentage of signal-intensity recovery (PSR) derived from dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging can distinguish recurrent metastatic tumor from radiation necrosis. MATERIALS AND METHODS: Twenty-seven patients with systemic cancer underwent gamma knife radiosurgery for metastatic lesions of the brain and subsequently developed enlarging regions of enhancement within the radiation field. Subsequent surgical resection or clinicoradiologic follow-up established a diagnosis of recurrent metastatic tumor or radiation necrosis. Perfusion MR imaging datasets were retrospectively reprocessed, and regions of interest were drawn around the entire contrast-enhancing region. The resulting T2* signal-intensity time curves produced rCBV, rPH, and PSR values for each examination. A Welch t test was used to compare imaging values between groups. RESULTS: The mean, minimum, and maximum PSR values were significantly lower ( P P CONCLUSIONS: The findings of our study suggest that perfusion MR imaging may be used to differentiate recurrent intra-axial metastatic tumor from gamma knife−induced radiation necrosis.
220 citations
TL;DR: In transforming low-grade glioma, susceptibility-weighted MR perfusion imaging can demonstrate significant increases in rCBV up to 12 months before contrast enhancement is apparent on T1- Weighted MR images.
Abstract: Purpose: To prospectively perform longitudinal magnetic resonance (MR) perfusion imaging of conservatively treated low-grade gliomas to determine whether relative cerebral blood volume (rCBV) changes precede malignant transformation as defined by conventional MR imaging and clinical criteria. Materials and Methods: All patients gave written informed consent for this institutional ethics committee–approved study. Thirteen patients (seven men, six women; age range, 29–69 years) with biopsy-proved low-grade glioma treated only with antiepileptic drugs were examined longitudinally with susceptibility-weighted perfusion, T2-weighted, fluid-attenuated inversion recovery, and high-dose contrast material–enhanced T1-weighted MR imaging at 6-month intervals to date or until malignant transformation was diagnosed. Student t tests were used to determine differences in rCBV values between “transformers” and “nontransformers” at defined time points throughout study follow-up. Results: Seven patients showed progression...
216 citations
TL;DR: Sixty-four-section CT angiography can help rule out hemodynamically relevant CAD in patients with intermediate to high pretest likelihood, although an abnormal CTAngiography study is a poor predictor of ischemia.
Abstract: PURPOSE: To prospectively determine the accuracy of 64-section computed tomographic (CT) angiography for the depiction of coronary artery disease (CAD) that induces perfusion defects at myocardial perfusion imaging with single photon emission computed tomography (SPECT), by using myocardial perfusion imaging as the reference standard MATERIALS AND METHODS: All patients gave written informed consent after the study details, including radiation exposure, were explained The study protocol was approved by the local institutional review board In patients referred for elective conventional coronary angiography, an additional 64-section CT angiography study and a myocardial perfusion imaging study (1-day adenosine stress-rest protocol) with technetium 99m-tetrofosmin SPECT were performed before conventional angiography Coronary artery diameter narrowing of 50% or greater at CT angiography was defined as stenosis and was compared with the myocardial perfusion imaging findings Quantitative coronary angiography served as a reference standard for CT angiography RESULTS: A total of 1093 coronary segments in 310 coronary arteries in 78 patients (mean age, 65 years +/- 9 [standard deviation]; 35 women) were analyzed CT angiography revealed stenoses in 137 segments (13%) corresponding to 91 arteries (29%) in 46 patients (59%) SPECT revealed 14 reversible, 13 fixed, and six partially reversible defects in 31 patients (40%) Sensitivity, specificity, and negative and positive predictive values, respectively, of CT angiography in the detection of reversible myocardial perfusion imaging defects were 95%, 53%, 94%, and 58% on a per-patient basis and 95%, 75%, 96%, and 72% on a per-artery basis Agreement between CT and conventional angiography was very good (96% and kappa = 092 for patient-based analysis, 93% and kappa = 084 for vessel-based analysis) CONCLUSION: Sixty-four-section CT angiography can help rule out hemodynamically relevant CAD in patients with intermediate to high pretest likelihood, although an abnormal CT angiography study is a poor predictor of ischemia
211 citations
TL;DR: ASL-PI may predict histopathologic vascular densities of brain tumors and may be useful in distinguishing between high- and low-grade gliomas and in differentiating hemangioblastomas from other brain tumors.
Abstract: BACKGROUND AND PURPOSE: We investigated the relationship between tumor blood-flow measurement based on perfusion imaging by arterial spin-labeling (ASL-PI) and histopathologic findings in brain tumors. MATERIALS AND METHODS: We used ASL-PI to examine 35 patients with brain tumors, including 11 gliomas, 9 meningiomas, 9 schwannomas, 1 diffuse large B-cell lymphoma, 4 hemangioblastomas, and 1 metastatic brain tumor. As an index of tumor perfusion, the relative signal intensity (SI) of each tumor (%Signal intensity) was determined as a percentage of the maximal SI within the tumor per averaged SI within normal cerebral gray matter on ASL-PI. Relative vascular attenuation (%Vessel) was determined as the total microvessel area per the entire tissue area on CD-34–immunostained histopathologic specimens. MIB1 indices of gliomas were also calculated. The differences in %Signal intensity among different histopathologic types and between high- and low-grade gliomas were compared. In addition, the correlations between %Signal intensity and %Vessel or MIB1 index were evaluated in gliomas. RESULTS: Statistically significant differences in %Signal intensity were observed between hemangioblastomas versus gliomas (P CONCLUSION: ASL-PI may predict histopathologic vascular densities of brain tumors and may be useful in distinguishing between high- and low-grade gliomas and in differentiating hemangioblastomas from other brain tumors.
198 citations
01 Jan 2008
176 citations
TL;DR: Arterial spin-labeled ASL perfusion imaging can be implemented successfully into a routine clinical neuroimaging protocol and can accurately demonstrate alterations in brain perfusion.
Abstract: Arterial spin-labeled (ASL) perfusion imaging can be implemented successfully into a routine clinical neuroimaging protocol and can accurately demonstrate alterations in brain perfusion. We have observed patterns of focal, regional, and global hyperperfusion in a wide variety of disease processes. The causes of hyperperfusion at clinical ASL have not been previously characterized. Focal lesions such as brain tumors and vascular malformations with increased perfusion can be well depicted by ASL. More global causes of hyperperfusion, including postanoxia vasodilation and hypercapnia, may go undetected on conventional MR images, whereas the regional hyperperfusion, which may occur in reversible encephalopathies and luxury perfusion, has been consistently illustrated on ASL cerebral blood flow maps at our institution.
TL;DR: Testing the hypothesis that reading perfusion scans with chest radiographs but without ventilation scans, and categorizing the perfusion scan as “pulmonary embolism (PE) present” or “PE absent,” can result in clinically useful sensitivity and specificity in most patients found it to provide diagnostic accuracy similar to both CTA and ventilation–perfusion scintigraphy, at lower cost and with lower radiation dose.
Abstract: We used the archived Prospective Investigation of Pulmonary Embolism Diagnosis II (PIOPED II) data and images to test the hypothesis that reading perfusion scans with chest radiographs but without ventilation scans, and categorizing the perfusion scan as ‘‘pulmonary embolism (PE) present’’ or ‘‘PE absent,’’ can result in clinically useful sensitivity and specificity in most patients. Methods: Patients recruited into PIOPED II were eligible for the present study if they had a CT angiography (CTA) or digital subtraction angiography (DSA) diagnosis, an interpretable perfusion scan and chest radiographs, and a Wells’ score. Four readers reinterpreted the perfusion scans and chest radiographs of eligible patients. Two readers used the modified PIOPED II criteria and 2 used the Prospective Investigative Study of Pulmonary Embolism Diagnosis (PISAPED) criteria. The chest radiographs were read as ‘‘normal/near normal,’’ ‘‘abnormal,’’ or ‘‘nondiagnostic,’’ and the perfusion scans were read as ‘‘PE present,’’ ‘‘PE absent,’’ or ‘‘nondiagnostic.’’ The primary analysis used a composite reference standard: the PIOPED II DSA result or, if there was no definitive DSA result, CTA results that were concordant with the Wells’ score as defined in PIOPED II (CTA positive and Wells’ score . 2, or CTA negative and Wells’ score , 6).Results: The prevalence of PE in the sample was 169 of 889 (19%). Using the modified PIOPED II criteria, the sensitivity of a ‘‘PE present’’ perfusion scan was 84.9% (95% confidence interval [CI], 80.1%288.8%), and the specificity of ‘‘PE absent’’ was 92.7% (95% CI, 91.1%294.1%), excluding ‘‘nondiagnostic’’ results, which occurred in 20.6% (95% CI, 18.8%222.5%). Using PISAPED criteria, the sensitivity of a ‘‘PE present’’ perfusion scan was 80.4% (95% CI, 75.9%284.3%) and the specificity of ‘‘PE absent’’ was 96.6% (95% CI, 95.5%297.4%), whereas the proportion of patients with ‘‘nondiagnostic’’ scans was 0% (95% CI, 0.0%20.2%). Conclusion: Perfusion scintigraphy combined with chest radiography can provide diagnostic accuracy similar to both CTA and ventilation–perfusion scintigraphy, at lower cost and with lower radiation dose. With modified PIOPED II criteria, a higher proportion of scans were nondiagnostic than with CTA, and with PISAPED criteria none were nondiagnostic.
TL;DR: In contrast-enhanced harmonic EUS (CEH-EUS) as discussed by the authors, the authors used a prototype echoendoscope equipped with an adequate broad-band transducer that can detect harmonic signals from the US contrast agents.
TL;DR: A mismatch ratio of 2.6 provided the highest sensitivity and specificity for identifying patients in whom reperfusion was associated with a favorable response, and a larger PWI/DWI ratio may provide greater power for detecting beneficial effects of reperfusions.
Abstract: Although the perfusion-weighted imaging/diffusion-weighted imaging (PWI/DWI) mismatch model has been proposed to identify acute stroke patients who benefit from reperfusion therapy, the optimal definition of a mismatch is uncertain. We evaluated the odds ratio for a favorable clinical response in mismatch patients with reperfusion compared with no reperfusion for various mismatch ratio thresholds in patients enrolled in the diffusion and perfusion imaging evaluation for understanding stroke evolution (DEFUSE) study. A mismatch ratio of 2.6 provided the highest sensitivity (90%) and specificity (83%) for identifying patients in whom reperfusion was associated with a favorable response. Defining mismatch with a larger PWI/DWI ratio may provide greater power for detecting beneficial effects of reperfusion.
TL;DR: Advanced MR and CT perfusion imaging measurements of core/penumbra mismatch for patient selection in stroke trials are highly correlated when CT perfusions coverage is sufficient to include most of the ischemic region.
Abstract: Background and Purpose— Our purpose was to determine (1) the correlation between quantitative CT and MR measurements of infarct core, penumbra, and mismatch; and (2) whether the difference between these measurements would alter patient selection for stroke clinical trials. Methods— We studied 45 patients with acute middle cerebral artery stroke imaged a mean of 3.8 hours after onset (range, 0.48 to 8.35 hours) who underwent CT perfusion and MR diffusion (DWI)/perfusion imaging within 3 hours of each other. The DWI and MR-mean transit time (MTT) abnormalities were visually segmented using a semiautomated commercial analysis program. The CT-cerebral blood volume) and CT-MTT lesions were automatically segmented using a relative cerebral blood volume threshold of 0.56 and a relative MTT threshold of 1.50 on commercially available software. Percent mismatch was defined as [(MTT−DWI)/DWI volume]×100. Pearson correlation coefficients were calculated. Results— There were significant correlations for DWI versus CT...
TL;DR: Sustained myocardial tracer uptake, combined with high image contrast, will allow for imaging protocols with tracer injection at peak exercise followed by delayed imaging, and the observation of a high and flow-independent first-pass extraction fraction promises linearity betweentracer uptake andMyocardial blood flow.
Abstract: PET allows for quantitative, regional myocardial perfusion imaging. The short half-lives of the perfusion tracers currently in use limit their clinical applicability. Here, the biodistribution and imaging quality of a new 18F-labeled myocardial perfusion agent (18F-BMS-747158-02) in an animal model are described. Methods: The biodistribution of 18F-BMS-747158-02 was determined at 10 and 60 min after injection. The first-pass extraction fraction of the tracer was measured in isolated rat hearts perfused with the Langendorff method. Small-animal PET imaging was used to study tracer retention. Results: The biodistribution at 10 min after injection demonstrated high myocardial uptake (3.1 percentage injected dose per gram [%ID/g]) accompanied by little activity in the lungs (0.3 %ID/g) and liver (1.0 %ID/g). The tracer showed a high and flow-independent myocardial first-pass extraction fraction, averaging 0.94 (SD = 0.04). PET imaging provided excellent delineation of myocardial structures. The heart-to-lung activity ratio increased from 4.7 to 10.2 between 1 and 15 min after tracer injection (at rest). Adenosine infusion (140 μg/kg/min) led to a significant increase in myocardial tracer retention (from 1.68 [SD = 0.23]) s−1 to 3.21 [SD = 0.92] s−1; P = 0.03). Conclusion: The observation of a high and flow-independent first-pass extraction fraction promises linearity between tracer uptake and myocardial blood flow. Sustained myocardial tracer uptake, combined with high image contrast, will allow for imaging protocols with tracer injection at peak exercise followed by delayed imaging. Thus, 18F-BMS-747158-02 is a promising new tracer for the quantitative imaging of myocardial perfusion and can be distributed to imaging laboratories without a cyclotron.
TL;DR: Significant associations between recanalization, reduced infarct growth, and favorable clinical response were documented in patients with a perfusion/diffusion mismatch who were treated with tPA within 3 to 6 hours after stroke onset.
Abstract: Background and Purpose— The purpose of this study was to determine the relationships between ischemic lesion growth, recanalization, and clinical response in stroke patients with and without a perfusion/diffusion mismatch. Methods— DEFUSE is an open label multicenter study in which 74 consecutive acute stroke patients were treated with intravenous tPA 3 to 6 hours after stroke onset. Magnetic resonance imaging (MRI) scans were obtained before, 3 to 6 hours after, and 30 days after treatment. Lesion growth was defined as the difference between the final infarct volume (30 day FLAIR) and the baseline diffusion lesion. Baseline MRI profiles were used to categorize 44 patients into Mismatch versus Absence of Mismatch subgroups. Early recanalization was assessed in 28 patients with an initial vessel lesion on magnetic resonance angiography. Infarct growth was compared based on whether a favorable clinical response (FCR) occurred and whether early recanalization was achieved. Results— In the Mismatch subgroup, ...
TL;DR: The maximum rCBV at pretreatment perfusion MR imaging is a useful clinical prognostic biomarker for survival in patients with high-grade astrocytoma.
Abstract: BACKGROUND AND PURPOSE: Although the prognostic value of perfusion MR imaging in various gliomas has been investigated, that in high-grade astrocytomas alone has not been fully evaluated. The purpose of this study was to evaluate retrospectively whether the tumor maximum relative cerebral blood volume (rCBV) on pretreatment perfusion MR imaging is of prognostic value in patients with high-grade astrocytoma. MATERIALS AND METHODS: Between January 1999 and December 2002, 49 patients (30 men, 19 women; age range, 23–76 years) with supratentorial high-grade astrocytoma underwent MR imaging before the inception of treatment. The patient age, sex, symptom duration, neurologic function, mental status, Karnofsky Performance Scale, extent of surgery, histopathologic diagnosis, tumor component enhancement, and maximum rCBV were assessed to identify factors affecting survival. Kaplan-Meier survival curves, the logrank test, and the multivariate Cox proportional hazards model were used to evaluate prognostic factors. RESULTS: The maximum rCBV was significantly higher in the 31 patients with glioblastoma multiforme than in the 18 with anaplastic astrocytoma (P 2.3) maximum rCBV value (P CONCLUSION: The maximum rCBV at pretreatment perfusion MR imaging is a useful clinical prognostic biomarker for survival in patients with high-grade astrocytoma.
TL;DR: Determinants of t CBF and total brain perfusion differed largely due to the large influence of brain volume on tCBF values, and it was found that Persons with low totalbrain perfusion had a significantly larger WML volume compared with those with high totalBrain perfusion.
Abstract: Reduced cerebral perfusion may contribute to the development of cerebrovascular and neurodegenerative diseases. Little is known on cerebral perfusion in the general population, as most measurement techniques are too invasive for application in large groups of healthy individuals. Total cerebral blood flow (tCBF) can be noninvasively measured by magnetic resonance imaging (MRI) but is highly correlated with brain volume. We calculated total brain perfusion by dividing tCBF by brain volume, and we investigated determinants of total brain perfusion in comparison with tCBF. Secondly, we studied whether persons with a low tCBF or low total brain perfusion have a larger volume of white matter lesions (WML). This study is based on 892 persons aged 60 to 91 years from the Rotterdam Study, a population-based cohort study. We performed two-dimensional (2D) phase-contrast MRI for tCBF measurement. Brain volume and WML volume were quantitatively assessed. Cardiovascular determinants were assessed by interview and physical examination. We assessed associations between cardiovascular determinants and flow measures with linear regression models, adjusted for age and sex. Associations between tCBF or total brain perfusion and WML volume were assessed using general linear models. We found that determinants of tCBF and total brain perfusion differed largely due to the large influence of brain volume on tCBF values. Persons with low total brain perfusion had a significantly larger WML volume compared with those with high total brain perfusion. Prospective studies are required to unravel whether hypoperfusion contributes to WML formation or that tissue damage, manifested by WML, leads to brain hypoperfusion.
TL;DR: It is found that PD patients with PG have abnormal resting state dysfunction of the mesocorticolimbic network possibly associated with a drug-induced overstimulation of relatively preserved reward-related neuronal systems, which supports the concept that PG is a "behavioral" addictive disorder.
Abstract: Background Pathological gambling (PG) may develop in patients with Parkinson disease (PD) during dopamine replacement therapy, but the underlying neural correlates are still unclear. Objective To investigate resting state brain perfusion in PD patients with active PG compared with matched PD controls and healthy controls. Design Case-control study. Setting Outpatient tertiary clinic. Participants Eleven right-handed PD patients with active PG according to Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition, Text Revision) criteria, 40 matched PD controls, and 29 age-matched healthy controls. Intervention All the participants underwent resting state brain perfusion single-photon emission computed tomography using technetium TC 99m ethylcysteinate dimer bicisate. All PD subjects were taking dopaminergic medication. Main Outcome Measure Statistical Parametric Mapping was used for data analysis ( P Results PD patients with PG showed resting state overactivity in a right hemisphere network that included the orbitofrontal cortex, the hippocampus, the amygdala, the insula, and the ventral pallidum. No areas of perfusion reduction were detected. Conclusions We found that PD patients with PG have abnormal resting state dysfunction of the mesocorticolimbic network possibly associated with a drug-induced overstimulation of relatively preserved reward-related neuronal systems. These findings support the concept that PG is a “behavioral” addictive disorder.
TL;DR: Manual base parameter placement reduces the effect that variability in image reconstruction has on phase analysis, and a high degree of reproducibility of phase analysis is observed.
Abstract: Background
A novel method to quantify dyssynchrony has been developed using phase analysis of gated single-photon emission computed tomography perfusion imaging. We report on the effect of variability in image reconstruction on the phase analysis results (repeatability) and on the interobserver and intraobserver reproducibility of the technique.
TL;DR: Given that previous studies have found PET to be cost-effective and the current findings of excellent sensitivity and specificity, the modality should be more widely considered as an initial test in the diagnosis of CAD.
TL;DR: In low-to-intermediate risk patients without known CHD, MDCT coronary artery plaque assessment successfully identify patients at higher risk of increased extent, severity and reversibility of myocardial perfusion defects by SPECT.
TL;DR: In this paper, the discriminant function analysis was used to identify variables that can predict inclusion in the neoplastic or non-neoplastic lesion groups, and the discriminating capability of 1H-MRSI and perfusion MR imaging was compared.
Abstract: BACKGROUND AND PURPOSE: Noninvasive diagnosis of brain lesions is important for the correct choice of treatment. Our aims were to investigate whether 1) proton MR spectroscopic imaging (1H-MRSI) can aid in differentiating between tumors and nonneoplastic brain lesions, and 2) perfusion MR imaging can improve the classification. MATERIALS AND METHODS: We retrospectively examined 69 adults with untreated primary brain lesions (brain tumors, n = 36; benign lesions, n = 10; stroke, n = 4; demyelination, n = 10; and stable lesions not confirmed on pathologic examination, n = 9). MR imaging and 1H-MRSI were performed at 1.5T before biopsy or treatment. Concentrations of N-acetylaspartate (NAA), creatine (Cr), and choline (Cho) in the lesion were expressed as metabolite ratios and were normalized to the contralateral hemisphere. Dynamic susceptibility contrast-enhanced perfusion MR imaging was performed in a subset of patients (n = 32); relative cerebral blood volume (rCBV) was evaluated. Discriminant function analysis was used to identify variables that can predict inclusion in the neoplastic or nonneoplastic lesion groups. Receiver operator characteristic (ROC) analysis was used to compare the discriminatory capability of 1H-MRSI and perfusion MR imaging. RESULTS: The discriminant function analysis correctly classified 84.2% of original grouped cases (P CONCLUSION: These results suggest a promising role for 1H-MRSI and perfusion MR imaging in the distinction between brain tumors and nonneoplastic lesions in adults.
TL;DR: In specific patient groups with cerebrovascular disease, selective ASL MR imaging provides valuable hemodynamic information when added to current MR protocols, and may contribute to a better understanding of the relation between the vasculature, perfusion, and brain function.
Abstract: The ability to visualize perfusion territories in the brain is important for many clinical applications. The aim of this overview is to highlight the possibilities of selective arterial spin-labeling (ASL) magnetic resonance (MR) imaging techniques in the assessment of the perfusion territories of the cerebral arteries. In the past decade, the optimization of selective ASL MR techniques to image the cerebral perfusion territories has resulted in numerous labeling approaches and an increasing number of clinical applications. In this article, the methods and clinical applications of selective ASL MR imaging are described and the importance of perfusion territory information in studying cerebral hemodynamic changes in patients with cerebrovascular disease is shown. In specific patient groups with cerebrovascular disease, such as acute stroke, large artery steno-occlusive disease, and arteriovenous malformation, selective ASL MR imaging provides valuable hemodynamic information when added to current MR protocols. As a noninvasive tool for perfusion territory measurements, selective ASL may contribute to a better understanding of the relation between the vasculature, perfusion, and brain function.
TL;DR: Different components of the inflammatory response that participate in vascular development and remodeling can be assessed separately with targeted molecular imaging.
Abstract: Background— Inflammatory responses contribute to vascular remodeling during tissue repair or ischemia. We hypothesized that inflammatory cell recruitment and endothelial cell activation during vasculogenesis and ischemia-mediated arteriogenesis could be temporally assessed by noninvasive molecular imaging. Methods and Results— Contrast ultrasound perfusion imaging and molecular imaging with microbubbles targeted to activated neutrophils, α5-integrins, or vascular cell adhesion molecule (VCAM-1) were performed in murine models of vasculogenesis (subcutaneous matrigel) or hind-limb ischemia produced by arterial occlusion in wild-type or monocyte chemotactic protein-1–deficient mice. In subcutaneous matrigel plugs, perfusion advanced centripetally between days 3 and 10. On targeted imaging, signal enhancement from α5-integrins and VCAM-1 coincided with the earliest appearance of regional blood flow. Targeted imaging correlated temporally with histological evidence of channel formation by α5-integrin–positive...
01 Jan 2008
TL;DR: In this paper, the incidence of renal sequelae is relatively low in acute stroke patients undergoing emergent multimodal CT scanning, if indicated, need not be delayed in those with no history of renal impairment.
Abstract: RESULTS: None of the 198 patients developed chronic kidney disease or required dialysis. Of 175 patients with serial creatinine measurements between baseline and day 3, 5 (2.9%) developed CIN. The incidence of CIN was 2% in patients who were scanned before a baseline creatinine level was available. CONCLUSION: The incidence of renal sequelae is relatively low in acute stroke patients undergoing emergent multimodal CT scanning. Prompt CTA/CTP imaging of acute stroke, if indicated, need not be delayed in those with no history of renal impairment.
TL;DR: The incidence of renal sequelae is relatively low in acute stroke patients undergoing emergent multimodal CT scanning and prompt CTA/CTP imaging of acute stroke, if indicated, need not be delayed in those with no history of renal impairment.
Abstract: BACKGROUND AND PURPOSE: Multimodal CT imaging with contrast-enhanced CT angiography (CTA) and CT perfusion (CTP) is increasingly being used to guide emergency management of acute stroke. However, little has been reported about the safety of intravenous contrast administration associated with these studies in the acute stroke population, including cases in which baseline creatinine values are unknown. We investigated the incidence of contrast-induced nephropathy (CIN), defined as a 25% or more increase in baseline creatinine levels within 72 hours of contrast administration and chronic kidney disease in patients receiving CTA±CTP at our regional stroke center. MATERIALS AND METHODS: We analyzed 198 patients who underwent contrast CT studies for evaluation of acute ischemic or hemorrhagic stroke at our center (2003–2007). Through retrospective chart abstraction, we analyzed serial creatinine levels (baseline to day 3) and later values (≥day 4) where available. The incidences of CIN and/or chronic kidney disease were documented. After power analysis, CIN and non-CIN groups were compared by using the unpaired t test, Wilcoxon rank sum test, or Fisher exact test. RESULTS: None of the 198 patients developed chronic kidney disease or required dialysis. Of 175 patients with serial creatinine measurements between baseline and day 3, 5 (2.9%) developed CIN. The incidence of CIN was 2% in patients who were scanned before a baseline creatinine level was available. CONCLUSION: The incidence of renal sequelae is relatively low in acute stroke patients undergoing emergent multimodal CT scanning. Prompt CTA/CTP imaging of acute stroke, if indicated, need not be delayed in those with no history of renal impairment.
TL;DR: A role for tissue perfusion impairment in NP dysfunction in MS patients with relapsing-remitting and primary-progressive MS is suggested.
Abstract: Although cognitive impairment is common in multiple sclerosis (MS), its pathophysiology is still poorly understood. Abnormalities of cerebral blood flow (CBF) have long been acknowledged in MS and advances in perfusion magnetic resonance imaging (MRI) allow for their assessment in vivo. We investigated the relationship between regional perfusion changes and neuropsychological (NP) dysfunctions in patients with relapsing-remitting and primary-progressive MS. Absolute CBF, cerebral blood volume (CBV) and mean transit time were measured in 32 MS patients and 11 healthy controls using dynamic susceptibility contrast-enhanced T2(*)-weighted MRI. A comprehensive NP test battery was administered to all patients. A mixed model analysis of covariance was performed for group comparisons in terms of perfusion measures in normal-appearing white matter (NAWM) and deep gray matter (GM). Pearson's correlations were used to describe the association of perfusion metrics with NP Z-scores. CBF and CBV values were significantly decreased in both NAWM and deep GM in MS patients compared with controls (P=0.01). In all patients, deep GM CBF was significantly associated with Rey Complex Figure Test (RCFT)-Copy (r=0.5; P=0.001) and deep GM CBV and NAWM CBV were significantly associated with Color-Word Interference Inhibition Switching test (D-KEFSIS) (r=0.4; P=0.008 and r=0.4; P=0.02). However, the only associations that remained significant after Bonferroni correction were between deep GM CBF and RCFT-Copy (P=0.006), and deep GM CBV and D-KEFSIS (P=0.04). Our results suggest a role for tissue perfusion impairment in NP dysfunction in MS. Large-scale studies are needed to characterize better this association.
TL;DR: To study regional cerebral blood perfusion with power Doppler ultrasound (PDU) imaging in appropriate‐for‐gestational age (AGA) fetuses and those with intrauterine growth restriction (IUGR) at different hemodynamic stages of fetal deterioration.
Abstract: Objectives To study regional cerebral blood perfusion with power Doppler ultrasound (PDU) imaging in appropriate-for-gestational age (AGA) fetuses and those with intrauterine growth restriction (IUGR) at different hemodynamic stages of fetal deterioration. Methods Brain blood perfusion was studied with PDU imaging, and the fractional moving blood volume (FMB V) was estimated in 56 growth-restricted and 56 AGA matched fetuses at 26-32 weeks of gestation. Fetuses with IUGR were classified according to progressi. on of hemodynamic deterioration as follows: Group 1, abnormal umbilical artery (UA) pulsatility index (PI) (mean > 2 SD, n = 13); Group 2, abnormal UA-PI and middle cerebral artery (MCA) PI (mean 2 SD) but atrial (a-wave) flow present (n = 16); and Group 4, absent or reversed DV atrial flow (n = 12). FMBV was calculated in the complete mid-sagittal, frontal, basal ganglia and cerebellar regions. Results In all growth-restricted fetuses, FMBV was significantly increased in all regions. Fetuses in Group 1 showed considerable increments in FMBV values in the frontal, complete mid-sagittal and cerebellar regions, and a mild increase in the basal ganglia. From Groups 2 to 4, there was a steady reduction (compared with Group 1) in frontal FMBV values (F = 3.25, P = 0.027) together with a significant increment in the basal ganglia values (F = 11.61, P < 0.001). A trend for increasing FMBV values was also observed in the cerebellum, whereas a decreasing trend was noted in the complete mid-sagittal area. Conclusions Brain perfusion in growth-restricted fetuses shows clear regional variations, which change with progression of hemodynamic deterioration. After an initial and early increase in the frontal area, progression of fetal deterioration was rapidly associated with a pronounced decrease in frontal perfusion, together with an increase towards the basal ganglia. Copyright (c) 2008 ISUOG. Published by John Wiley & Sons, Ltd. (Less)