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  • Albers, Gregory W  (3)
  • 2000-2004  (3)
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  • 2000-2004  (3)
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  • 1
    Online Resource
    Online Resource
    Ovid Technologies (Wolters Kluwer Health) ; 2001
    In:  Stroke Vol. 32, No. suppl_1 ( 2001-01), p. 317-318
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 32, No. suppl_1 ( 2001-01), p. 317-318
    Abstract: 11 Background and purpose Methods for determining CBF using IV bolus tracking MRI have recently become available. Reduced apparent diffusion coefficient (ADC) values of brain tissue are associated with reductions in regional cerebral blood flow (rCBF). We studied the clinical and radiological features of patients with severe reductions of rCBF on MRI and analysed the relationship between reduced rCBF and ADC. Methods We studied patients with non-lacunar acute ischemic stroke in whom PWI and DWI MRI were performed within 7 hours after symptom onset. A PWI 〉 DWI mismatch of 〉 20% was required. Maps of rCBF, cerebral blood volume (rCBV) and mean transit time (rMTT) were generated after deconvoluting the measured concentration-time curve with the arterial input function using singular value decomposition. The ischemic lesion was outlined on the MTT map and the region of interest (ROI) transferred to the rCBF and rCBV map. ADC-maps were calculated. ADC lesions were defined as regions with ADC values ≤ 550 μm m2/sec. We compared the characteristics of patients with ischemic lesions that had a relative CBF of 〈 50% to the contralateral hemisphere to patients with lesions that had relative CBF of 〉 50%. Characteristics analysed included age, time to MRI, baseline NIHSS, mean ADC, DWI lesion volume, PWI lesion volume and absolute mismatch volume. Results Fifteen patients with an initial PWI 〉 DWI mismatch of 〉 20% were included. Ten had lesions with rCBF of 〉 50% (median 60%) and five patients had rCBF of 〈 50% (median 27.7%). Patients with rCBF 〈 50% had lower ADC values (median 431 μmm2/sec versus 506 μ mm2/sec, p=0.028), larger DWI volumes (median 75.6 cm 3 versus 8.6 cm 3 , p=0.001) and larger PWI lesions as defined by the MTT volume (median 193 cm 3 versus 69 cm 3 , p=0.028) and more severe baseline NIHSS scores (median 18 versus 9, p=0.019). The rMTT and rCBV of the lesions were similar in both groups, as were the age, the absolute mismatch volume and the time from symptom onset to MRI. Conclusion These data indicate that ischemic lesions with severe CBF reductions, measured with new MRI techniques, are associated with a lower mean ADC, larger DWI and PWI lesion volumes and a higher NIHSS score.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2001
    detail.hit.zdb_id: 1467823-8
    Location Call Number Limitation Availability
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  • 2
    Online Resource
    Online Resource
    Elsevier BV ; 2004
    In:  Journal of the American College of Cardiology Vol. 43, No. 6 ( 2004-03), p. 929-935
    In: Journal of the American College of Cardiology, Elsevier BV, Vol. 43, No. 6 ( 2004-03), p. 929-935
    Type of Medium: Online Resource
    ISSN: 0735-1097
    RVK:
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2004
    detail.hit.zdb_id: 1468327-1
    Location Call Number Limitation Availability
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  • 3
    Online Resource
    Online Resource
    Ovid Technologies (Wolters Kluwer Health) ; 2001
    In:  Stroke Vol. 32, No. suppl_1 ( 2001-01), p. 317-317
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 32, No. suppl_1 ( 2001-01), p. 317-317
    Abstract: 9 The degree of expansion of the early DWI lesion into the volume of the baseline PWI lesion is variable. In some patients partial recruitment of the DWI lesion volume occurs, while other patients develop a DWI lesion that equals or exceeds the size of the initial PWI volume. We investigated whether a quantitative analysis of the severity of the early perfusion deficit predicted the evolution of the PWI/DWI mismatch. Methods We studied patients with acute ischemic stroke in whom PWI and DWI MRI were performed within 7 hours after symptom onset and after 4–5 days. Maps of CBF, CBV and Mean Transit Time(MTT)were created after deconvolution of the arterial input function with the time-concentration curve. We compared the lesion volume on DWI at f/u with the baseline MTT volume. Patients in whom the lesion volume on DWI at f/u was smaller than the initial PWI deficit (group 1) were compared with patients in whom the DWI lesion at f/u (group 2) was ≥ than the initial PWI volume. Characteristics analysed included age, NIHSS, time to MRI, initial DWI volume, initial PWI volume, absolute mismatch volume, relative MTT(rMTT), CBF(rCBF) and CBV (rCBV) of the baseline PWI. Results Thirteen patients had an initial PWI 〉 DWI mismatch of 〉 20%. Seven of these patients (group 1) had DWI lesions at f/u that were smaller than the initial PWI lesion (mean 55% of PWI volume), while in 4 patients (group 2) the f/u DWI volume was larger than the PWI volume (mean 121% of initial PWI volume). Only the median rMTT (2.7 [group 1] versus 5.2 [group 2] , p=0.006) and the median rCBV (1.4 [group 1] versus 2.7 [group 2] , p=0.006) differed between the two groups. The initial rMTT and rCBV correlated significantly with the degree of expansion of the DWI lesion (ρ= 0.918 for rMTT and 0.864 for rCBV, p 〈 0.01). Two patients, who were excluded because of early reperfusion, had no substantial increase in the size of the initial DWI lesion despite severely increased rMTT and rCBV. Conclusion Among acute stroke patients with PWI 〉 DWI, who do not have early reperfusion, the degree of expansion of the initial DWI lesion correlates with the severity of the initial perfusion deficit as measured by the rMTT and the rCBV.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2001
    detail.hit.zdb_id: 1467823-8
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
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