Acute cerebral ischemia: evaluation with dynamic contrast-enhanced MR imaging and MR angiography.

Warach, Steven; Li, Wei; Ronthal, Michael; Edelman, Robert R.

doi:10.1148/radiology.182.1.1727307

Cited by 149 publications

(53 citation statements)

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“…In addition, the use of only DWI signal intensity can be problematic due the possibility of "T2 shine through" phenomena. [41][42][43] Finally, the temporal evolution of the DWI/ADC mapping is well known to be "biphasic" and renormalizes as the tissue progresses toward necrosis, which could explain the lack DWI hyperintensity in the patients at the time of observation. [44][45][46][47] The current study extends the use of DWI and ADC mapping in the treatment of uterine fibroids and suggests that a multiparametric approach ͑cT 1 WI, DWI, and T 2 WI͒ is useful for monitoring uterine tissue after MRg-HIFUS treatment.…”

Section: Discussionmentioning

confidence: 99%

Comparison between diffusion‐weighted imaging, ‐weighted, and postcontrast ‐weighted imaging after MR‐guided, high intensity, focused ultrasound treatment of uterine leiomyomata: Preliminary results

2010

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Purpose:To investigate the comparison between diffusion-weighted imaging ͑DWI͒, T 2 -weighted imaging, ͑T 2 WI͒ and contrast T 1 -weighted imaging ͑cT 1 WI͒ in uterine leiomyoma following treatment by magnetic resonance imaging-guided, high intensity focused ultrasound surgery ͑MRg-HIFUS͒. Methods: Twenty one patients ͑45Ϯ 5 yrs͒ with clinical symptoms of uterine leiomyoma ͑fibroids͒ were treated by MRg-HIFUS using an integrated 1.5T MRI-HIFUS system. MRI parameters consisted of DWI, T 2 WI, and T 1 -weighted fast spoiled gradient echo before and after contrast. The post-MRg-HIFUS treatment volume in the fibroid was assessed by cT 1 WI and DWI. Trace apparent diffusion coefficient maps were constructed for quantitative analysis. The regions of the treated uterine tissue were defined by a semisupervised segmentation method called the "eigenimage filter," using both cT 1 WI and DWI. Signal-to-noise ratios were determined for the T 2 WI pretreatment images. Segmented regions were tested by a similarity index for congruence. Descriptive, regression, and Bland-Altman statistics were calculated. Results: All the patients exhibited heterogeneously increased DWI signal intensity localized in the treated fibroid regions and were colocalized with the cT 1 WI defined area. The mean pretreatment T 2 WI signal intensity ratios were T 2 WI/ muscle= 1.8Ϯ 0.7 and T 2 WI/ myometrium= 0.7Ϯ 0.4. The congruence between the regions was significant, with a similarity of 84% and a difference of 8% between the regions. Regression analyses of the cT 1 WI and DWI segmented treatment volumes were found to be significantly correlated ͑r 2 = 0.94, p Ͻ 0.05͒ with the linear equation, ͑cT 1 WI͒ = 1.1͑DWI͒ − 0.66. There is good agreement between the regions defined by cT1WI and DWI in most of the cases as shown from the Bland-Altman plots. Conclusions: Diffusion-weighted imaging exhibited excellent agreement, congruence, and correlation with the cT 1 WI-defined region of treatment in uterine fibroid. Therefore, DWI could be useful as an adjunct for assessing treatment of uterine fibroids by MRg-HIFUS.

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Section: Discussionmentioning

confidence: 99%

Comparison between diffusion‐weighted imaging, ‐weighted, and postcontrast ‐weighted imaging after MR‐guided, high intensity, focused ultrasound treatment of uterine leiomyomata: Preliminary results

2010

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“…The most popular magnetic resonance (MR) angiographic techniques used in clinical practice include time-offl ight (TOF) MR angiography ( 11 ), phasecontrast MR angiography ( 12 ), and dynamic contrast material-enhanced MR angiography ( 13 ). Dynamic contrastenhanced MR angiography can be used to obtain high-spatial-resolution angiograms with varying degrees of temporal resolution ( 14 ).…”

Section: Methodsmentioning

confidence: 99%

Time-resolved Vessel-selective Digital Subtraction MR Angiography of the Cerebral Vasculature with Arterial Spin Labeling

et al. 2010

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Purpose:To demonstrate an arterial spin-labeling (ASL) magnetic resonance (MR) angiographic technique that covers the entire cerebral vasculature and yields transparent-background, time-resolved hemodynamic, and vessel-specifi c information similar to that obtained with x-ray digital subtraction angiography (DSA) without the use of exogenous contrast agents. Materials and Methods:Prior institutional review board approval and written informed consent were obtained for this HIPAA-compliant study in which 12 healthy volunteers (fi ve women, seven men; age range, 21-62 years; average age, 28 years) underwent imaging. An ASL technique in which variable labeling durations are used to acquire hemodynamic infl ow information and a vessel-selective pulsed-continuous ASL technique were tested. Region-of-interest signal intensities in various vessel segments were averaged across subjects and used to quantitatively compare images. For comparison, a standard time of fl ight (TOF) acquisition was performed in the circle of Willis. Results:Infl ow temporal resolution of 200 msec was demonstrated, revealing arterial transit times of 750, 950, and 1100 msec to consecutive segments of the middle cerebral artery from distal to the circle of Willis to deep regions of the midbrain. Selective labeling resulted in an average of eightfold suppression of contralateral vessels relative to the labeled vessel. Signal-to-noise ratios and contrast-to-noise ratios on maximum intensity projection images obtained with 88-second volumetric acquisitions (60 6 15 [standard deviation] and 57 6 15, respectively) and 11-second single-projection acquisitions (19 6 5 and 17 6 5, respectively) were comparable with standard TOF acquisitions, in which a 2.7-fold longer imaging duration for a 2.6-fold lower pixel area was used. Normal variations of the vasculature were identifi ed with ASL angiography. Conclusion:ASL angiography can be used to acquire hemodynamic vessel-specifi c information similar to that obtained with x-ray DSA.q RSNA, 2010

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“…Principles and techniques for perfusion imaging in pa tients with acute stroke have been previously described (Belliveau et aI., 1990;Edelman et aI., 1990;Rosen et ai., 1990;Warach et a!., 1992b). During repetitive scanning with a susceptibility-weighted (T2-weighted) pulse se quence, a bolus injection of 20 cc of gadopentatate dimeglumine was administered intravenously via an 18-gauge catheter placed in an antecubital vein by manual injection for -5 s followed by a saline flush.…”

Section: Perfusion Imagingmentioning

confidence: 99%

Clinical Outcome in Ischemic Stroke Predicted by Early Diffusion-Weighted and Perfusion Magnetic Resonance Imaging: A Preliminary Analysis

Warach

Dashe

Edelman

1996

J Cereb Blood Flow Metab

440

243

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Summary: Perfusion and diffusion-weighted magnetic resonance imaging (MRI) can demonstrate, respectively, cerebral ischemia and ischemic brain injury in the first several hours after onset of symptoms, when proton den sity and T2-weighted MRI may appear normal. It is hy pothesized that these techniques could distinguish re gions destined for infarction from those that will not prog ress to infarction, We provide preliminary evidence from an analysis of 19 patients with severely disabling clinical deficits attributable to ischemia in at least an entire divi sion of the middle cerebral artery, that initial perfusion and diffusion MRI were more accurate than conventional MRI in predicting no, partial or complete improvement-

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Acute cerebral ischemia: evaluation with dynamic contrast-enhanced MR imaging and MR angiography.

Cited by 149 publications

References 0 publications

Comparison between diffusion‐weighted imaging, ‐weighted, and postcontrast ‐weighted imaging after MR‐guided, high intensity, focused ultrasound treatment of uterine leiomyomata: Preliminary results

Comparison between diffusion‐weighted imaging, ‐weighted, and postcontrast ‐weighted imaging after MR‐guided, high intensity, focused ultrasound treatment of uterine leiomyomata: Preliminary results

Time-resolved Vessel-selective Digital Subtraction MR Angiography of the Cerebral Vasculature with Arterial Spin Labeling

Clinical Outcome in Ischemic Stroke Predicted by Early Diffusion-Weighted and Perfusion Magnetic Resonance Imaging: A Preliminary Analysis

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