scholarly journals Analysis of Combined Treatment of Embolic Stroke in Rat with r-tPA and a GPIIb/IIIa Inhibitor

2005 ◽  
Vol 25 (1) ◽  
pp. 87-97 ◽  
Author(s):  
Guangliang Ding ◽  
Quan Jiang ◽  
Li Zhang ◽  
Zheng Gang Zhang ◽  
Lian Li ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Thrombolytic Therapy ◽  
Combination Treatment ◽  
Infarct Volume ◽  
Embolic Stroke ◽  
Control Group ◽  
Resonance Imaging ◽  
Cerebral Microvessels ◽  
Magnetic Resonance Imaging Mri

Suppression of platelet activation improves the efficacy of thrombolytic therapy for stroke. Thus, combination treatment with recombinant tissue plasminogen activator (r-tPA) and 7E3 F(ab′)2, a GPIIb/IIIa inhibitor that binds the platelet to fibrin, may improve the efficacy of thrombolytic therapy in embolic stroke. Magnetic resonance imaging (MRI) was used to monitor treatment response in rats subjected to embolic middle cerebral artery (MCA) occlusion (MCAo). Animals were randomized into treated ( n = 12) and control ( n = 10) groups and received intravenous combination therapy or saline, respectively, 4 hours after MCAo. Magnetic resonance imaging (MRI) measurements performed 1 hour after MCAo showed no difference between groups. However, an increased incidence (50%) of MCA recanalization was found in the treated group at 24 hours compared with 20% in the control group. The area of low cerebral blood flow at 24 and 48 hours was significantly smaller in the combination treatment group, and the lesion size, as indicated from the T2 and T1 maps, differed significantly between groups. Fluorescence microscopy measurements of cerebral microvessels perfused with fluorescein isothiocyanate-dextran and measurements of infarct volume revealed that the combination treatment significantly increased microvascular patency and reduced infarct volume, respectively, compared with the control rats. The efficacy of combination treatment 4 hours after ischemia is reflected by MRI indices of tissue perfusion, MCA recanalization, and reduction of lesion volume. The treatment also reduced secondary microvascular perfusion deficits.

A Study of Epileptic Psychosis Using Magnetic Resonance Imaging

1990 ◽  
Vol 156 (2) ◽  
pp. 231-235 ◽  
Author(s):  
P. Conlon ◽  
M. R. Trimble ◽  
D. Rogers
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Temporal Lobe ◽  
Relaxation Times ◽  
Control Group ◽  
Resonance Imaging ◽  
Left Temporal Lobe ◽  
Magnetic Resonance Imaging Mri ◽  
Patients With Epilepsy ◽  
State Examination

Magnetic resonance imaging (MRI) was used in patients with epilepsy and psychosis. From 50 patients with epilepsy, a subgroup of 12 patients were categorised by the Present State Examination (PSE) as having nuclear schizophrenia (NS) and then compared with an epileptic control group with no psychiatric history. Further, patients with hallucinations were compared with patients without hallucinations. No differences in T1 relaxation times in any regions of interest were noted in the NS group compared with the other group. However, patients with hallucinations had a significantly higher T1 value in the left temporal lobe. These findings support the concept that specific abnormalities in limbic system structures relate to the phenomenology of the psychoses of epilepsy, especially left temporal lobe epilepsy.

scholarly journals Delayed rt-PA Treatment in a Rat Embolic Stroke Model: Diagnosis and Prognosis of Ischemic Injury and Hemorrhagic Transformation with Magnetic Resonance Imaging

2001 ◽  
Vol 21 (8) ◽  
pp. 964-971 ◽  
Author(s):  
Rick M. Dijkhuizen ◽  
Minoru Asahi ◽  
Ona Wu ◽  
Bruce R. Rosen ◽  
Eng H. Lo
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Thrombolytic Therapy ◽  
Recombinant Tissue Plasminogen Activator ◽  
Hemorrhagic Transformation ◽  
Embolic Stroke ◽  
Flow Index ◽  
Stroke Model ◽  
Resonance Imaging ◽  
Spontaneously Hypertensive

The authors characterized effects of late recombinant tissue plasminogen activator (rt-PA) administration in a rat embolic stroke model with magnetic resonance imaging (MRI), to assess potential MRI correlates, or predictors, or both, of rt-PA–induced hemorrhage. Diffusion-, perfusion-, and postcontrast T1 -weighted MRI were performed between 4 and 9 hours and at 24 hours after embolic stroke in spontaneously hypertensive rats. Treatment with either rt-PA or saline was started 6 hours after stroke. A spectrophotometric hemoglobin assay quantified hemorrhage severity. Before treatment, relative cerebral blood flow index (rCBFi) and apparent diffusion coefficient (ADC) in the ischemic territory were 30% ± 23% and 60% ± 5% (of contralateral), respectively, which increased to 45% ± 39% and 68% ± 4% 2 hours after rt-PA. After 24 hours, rCBFi and ADC were 27% ± 27% and 59 ± 5%. Hemorrhage volume after 24 hours was significantly greater in rt-PA–treated animals than in controls (8.7 ± 3.7 μL vs. 5.1 ± 2.4 μL, P < 0.05). Before rt-PA administration, clear postcontrast T1 -weighted signal intensity enhancement was evident in areas of subsequent bleeding. These areas had lower rCBFi levels than regions without hemorrhage (23% ± 22% vs. 36% ± 29%, P < 0.05). In conclusion, late thrombolytic therapy does not necessarily lead to successful reperfusion. Hemorrhage emerged in areas with relatively low perfusion levels and early blood–brain barrier damage. Magnetic resonance imaging may be useful for quantifying effects of thrombolytic therapy and predicting risks of hemorrhagic transformation.

scholarly journals Use of ultrasound combined with magnetic resonance imaging for diagnosis of breast masses and fibroids

2019 ◽  
Vol 47 (7) ◽  
pp. 3070-3078 ◽  
Author(s):  
Wei Xiang ◽  
Zihui Huang ◽  
Chenhu Tang ◽  
Bo Shen ◽  
Qun Yu ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Clinical Data ◽  
Diagnostic Performance ◽  
Test Group ◽  
Control Group ◽  
Resonance Imaging ◽  
Clinical Value ◽  
Breast Masses ◽  
Magnetic Resonance Imaging Mri

Objective To investigate the clinical value of ultrasound plus magnetic resonance imaging (MRI) for the diagnosis of breast masses and fibroids. Methods Clinical data for 357 patients with breast masses diagnosed at our hospital were analyzed retrospectively. The diagnostic performances were compared between 243 patients who underwent routine ultrasound examinations (control group) and 114 patients who underwent routine ultrasound plus MRI (test group). Results The overall accordance rates of routine ultrasound and routine ultrasound plus MRI for the diagnosis of breast masses, based on postoperative pathological diagnoses, were 70.78% (172/243) and 90.35% (103/114). The addition of MRI significantly improved the overall diagnostic performance of routine ultrasound for breast masses. The diagnostic accordance rate of routine ultrasound for the diagnosis of breast fibroids (fibroadenomas) was 74.12% (63/85 cases) compared with 93.94% (31/33 cases) for routine ultrasound plus MRI. The diagnostic performance of routine ultrasound plus MRI was therefore also significantly higher than routine ultrasound alone for diagnosing breast fibroids. Conclusions Routine ultrasound plus MRI can greatly improve the diagnostic accordance rates for breast masses and fibroadenomas.

scholarly journals Effect of pre-instruction on anxiety levels of patients undergoing magnetic resonance imaging examination

2001 ◽  
Vol 7 (3) ◽  
pp. 519-525 ◽  
Author(s):  
M. A. Selim
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Total Sample ◽  
Magnetic Resonance Imaging Examination ◽  
Control Group ◽  
Relaxation Techniques ◽  
Resonance Imaging ◽  
Before And After ◽  
Magnetic Resonance Imaging Mri ◽  
And Training

Thistudy investigated differences in anxiety level of patients who received instruction prior to magnetic resonance imaging [MRI] compared to a control group that did not. Thus, 60 patients were randomly assigned to two groups. Patients in the study group received instructions designed by the researcher plus the routine hospital instructions, while the control group received the routine hospital instructions only. The State-Trait Anxiety Inventory was administered to both groups before and after MRI examination. Patients who received the designed instructions reported significantly lower levels of anxiety than the controls. The findings also indicated that 60% of the total sample used prayer to reduce anxiety. The study emphasizes the need for detailed information about the procedure and training in relaxation techniques.

Amyloid Angiopathy in Brain Hemorrhage: A Postmortem Neuropathological-Magnetic Resonance Imaging Study

2018 ◽  
Vol 45 (3-4) ◽  
pp. 124-131 ◽  
Author(s):  
Celine Guidoux ◽  
Jean-Jacques Hauw ◽  
Isabelle F. Klein ◽  
Julien Labreuche ◽  
Claudine Berr ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Risk Factors ◽  
Magnetic Resonance ◽  
Histological Analysis ◽  
Imaging Study ◽  
Control Group ◽  
Amyloid Angiopathy ◽  
Resonance Imaging ◽  
Significant Difference ◽  
Magnetic Resonance Imaging Mri

Background: Risk factors for intracerebral hemorrhage (ICH) include hypertension and cerebral amyloid angiopathy (CAA). The objective of this study was to determine the autopsy prevalence of CAA and the potential overlap with other risk factors among patients who died from ICH and also the correlation of CAA with cerebral microbleeds. Methods: We analyzed 81 consecutive autopsy brains from patients with ICH. Staining for CAA detection was performed. We used an age- and sex-matched control group of routine brain autopsies of nonneurological patients to determine the frequencies of CAA and hypertension. Postmortem 3D T2-weighted gradient-echo magnetic resonance imaging (MRI) with a 1.5-T magnet was performed in 11 brains with ICH (5 with CAA and 6 without) and histological correlation was performed when microbleeds were detected. Results: Hypertension and CAA were found in 69.1 and 24.7% of cases respectively. Among patients with CAA, 65.0% also had hypertension. The prevalence of CAA was similar among non-hypertensive cases and controls (33.3 and 23.1%; p = 0.54), whereas a significant difference was found between hypertensive cases vs. controls (28.9% vs. 0; p = 0.01). MRI documented 48 microbleeds and all 5 brains with CAA had ≥1 microbleed, compared to 3/6 brains without CAA. Among 48 microbleeds on MRI, 45 corresponded histologically to microbleeds surrounding microvessels (23 <200 µm in diameter, 19 between 200 µm and 2 mm, 3 were hemosiderin granules). Conclusions: Both hypertension and CAA frequently coexist in patients with ICH. MRI-detected microbleeds, proven by histological analysis, were twice as common in patients with CAA as in those with hypertensive ICH.

scholarly journals Computational modeling identifies embolic stroke of undetermined source patients with potential arrhythmic substrate

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Savannah F Bifulco ◽  
Griffin D Scott ◽  
Sakher Sarairah ◽  
Zeinab Birjandian ◽  
Caroline H Roney ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Atrial Fibrillation ◽  
Cardiac Magnetic Resonance ◽  
Magnetic Resonance ◽  
Computational Modeling ◽  
Cardiac Magnetic Resonance Imaging ◽  
Embolic Stroke ◽  
Resonance Imaging ◽  
Substrate Properties ◽  
Magnetic Resonance Imaging Mri

Cardiac magnetic resonance imaging (MRI) has revealed fibrosis in embolic stroke of undetermined source (ESUS) patients comparable to levels seen in atrial fibrillation (AFib). We used computational modeling to understand the absence of arrhythmia in ESUS despite the presence of putatively pro-arrhythmic fibrosis. MRI-based atrial models were reconstructed for 45 ESUS and 45 AFib patients. The fibrotic substrate's arrhythmogenic capacity in each patient was assessed computationally. Reentrant drivers were induced in 24/45 (53%) ESUS and 22/45 (49%) AFib models. Inducible models had more fibrosis (16.7±5.45%) than non-inducible models (11.07±3.61%; P<0.0001); however, inducible subsets of ESUS and AFib models had similar fibrosis levels (P=0.90), meaning the intrinsic pro-arrhythmic substrate properties of fibrosis in ESUS and AFib are indistinguishable. This suggests some ESUS patients have latent pre-clinical fibrotic substrate that could be a future source of arrhythmogenicity. Thus, our work prompts the hypothesis that ESUS patients with fibrotic atria are spared from AFib due to an absence of arrhythmia triggers.

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