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[Acute ischemic cerebral infarct: prospective serial observations by magnetic resonance imaging]
T Egelhof1, M Essig, R von Kummer
1Abt. Neuroradiologie, Universität Heidelberg.
Aim:
Serial observations of acute ischaemic cerebral infarcts by MRI in order to define signal patterns, contrast uptake, oedema and secondary haemorrhage over a period of three months.
Methods:
Prospective serial examinations of 34 patients with acute cerebral ischaemia who were examined during the first 48 hours, on days 3 or 4, 7, 14, 21, 28 and after three months by MRI (spin echo TR/TE 2200/100/20, 500/20, +/- Gd).
Results:
T2 weighted spin echo sequences showed the highest sensitivity (88%) during the first 8 hours of cerebral ischaemia when compared with other spin echo sequences. Parenchymal contrast enhancement showed a distinct peak during the second and third weeks. The use of contrast did not improve diagnosis of an infarct during any stage. 87% of lesions showed haemorrhage at some stage. Vascular enhancement was observed in 25% of infarcts during the first 24 hours and was still present after three months in 20%. Parenchymal and vascular enhancement, and haemorrhage correlate with the size of the infarct.
Conclusion:
Focal cerebral ischaemia produces an abnormality of the blood-brain barrier, oedema and finally necrosis, depending on the severity and duration of the lesion. Haemorrhage in 87% was considerably more common than has been described previously. Vascular enhancement is not an early sign of an infarct, contrary to what has been described in the literature.
Insights
Serial MRI scans reveal that hemorrhage is common in acute cerebral infarcts, occurring in 87% of cases. Contrast enhancement is not an early diagnostic sign, peaking in the second and third weeks post-infarct.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- Acute cerebral infarcts involve complex pathophysiological changes.
- Understanding the temporal evolution of these changes is crucial for diagnosis and management.
Purpose of the Study:
- To longitudinally characterize MRI signal patterns, contrast enhancement, edema, and secondary hemorrhage in acute ischemic cerebral infarcts over three months.
- To define the diagnostic utility of various MRI sequences and contrast administration.
Main Methods:
- Prospective serial MRI examinations of 34 patients with acute cerebral ischemia.
- Scans were performed within 48 hours and at multiple intervals up to three months, utilizing spin-echo sequences with and without gadolinium contrast.
Main Results:
- T2-weighted spin-echo sequences demonstrated the highest sensitivity (88%) within the first 8 hours.
- Parenchymal contrast enhancement peaked during weeks 2-3; contrast did not improve early infarct diagnosis.
- Hemorrhage was observed in 87% of lesions, and vascular enhancement was noted in 25% within 24 hours, persisting in 20% at three months.
Conclusions:
- Acute focal cerebral ischemia leads to blood-brain barrier abnormalities, edema, and necrosis.
- Hemorrhage is significantly more common in infarcts than previously reported.
- Vascular enhancement is not an early indicator of infarct, contrary to existing literature.