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Detection of intracranial hemorrhage: comparison between gradient-echo images and b(0) images obtained from
D D Lin1, C G Filippi, A B Steever
1Department of Radiology, Division of Neuroradiology, New York Presbyterian Hospital, 525 E. 68th St., New York, NY 10021, USA.
Background And Purpose:
Diffusion-weighted MR imaging (DWI) is commonly used as the initial and sole imaging examination for the detection of acute cerebral infarction, yet it remains controversial whether MR can detect hyperacute (<24 h) hemorrhage. Hemorrhage is best detected with gradient-echo (GRE) T2*-weighted sequences, because of their magnetic susceptibility effects. DWI uses a spin-echo echo-planar technique (EPI) that is more sensitive than spin-echo T2-weighted imaging to susceptibility effects. Our aim was to determine whether the b(0) image from the DWI-EPI sequence is as sensitive as GRE in detecting hemorrhagic lesions on imaging studies performed to identify acute infarction or hemorrhage.
Methods:
All MR studies performed for clinically suspected or radiographically confirmed acute infarction or hemorrhage from 2/1/98 to 8/15/99 were retrospectively interpreted by one neuroradiologist in a blinded fashion. The sensitivity of hemorrhage detection, conspicuity of lesions, and diagnostic certainty were compared between the b(0) EPI and GRE sequences.
Results:
We found 101 acute infarcts, of which 13 were hemorrhagic, as evidenced by the presence of hypointensity within the infarction on the GRE sequence. This finding served as the reference standard for detection of hemorrhage. Hemorrhage was diagnosed with confidence in only seven cases (54%) on b(0) images; 22 acute hematomas were hypointense on GRE images whereas 19 were hypointense on b(0) images (86%); 17 chronic hematomas were depicted on GRE images and 12 on b(0) scans (63%). Punctate hemorrhages and linear cortical staining were detected on 37 GRE studies but on only four b(0) studies. Hemorrhage was always more conspicuous on the GRE sequences.
Conclusion:
b(0) images from a DWI sequence failed to detect minimally hemorrhagic infarctions and small chronic hemorrhages associated with microangiopathy. GRE scans were more sensitive than b(0) images in the detection of these hemorrhages and should be included in emergency brain MR studies for acute infarction, especially when thrombolytic therapy is contemplated.
Insights
Gradient-echo (GRE) sequences are more sensitive than diffusion-weighted imaging (DWI) b(0) images for detecting hyperacute and chronic hemorrhages in the brain. GRE scans should be included in emergency brain MR studies for acute infarction, especially when thrombolytic therapy is considered.
Area of Science:
- Neuroradiology
- Medical Imaging
Background:
- Diffusion-weighted MR imaging (DWI) is standard for acute cerebral infarction detection.
- Detecting hyperacute (<24h) hemorrhage with MR remains controversial.
- Gradient-echo (GRE) T2*-weighted sequences are optimal for hemorrhage detection due to magnetic susceptibility effects.
Purpose of the Study:
- To compare the sensitivity of DWI b(0) images versus GRE sequences in detecting hemorrhagic lesions.
- To evaluate MR's capability in identifying hyperacute hemorrhage.
Main Methods:
- Retrospective analysis of MR studies for suspected acute infarction or hemorrhage.
- Blinded interpretation by a neuroradiologist comparing b(0) EPI and GRE sequences.
- Assessment of hemorrhage detection sensitivity, lesion conspicuity, and diagnostic certainty.
Main Results:
- GRE sequences detected more acute and chronic hematomas than b(0) images.
- Hemorrhage detection confidence was lower with b(0) images (54%) compared to GRE.
- Punctate hemorrhages and linear cortical staining were better visualized on GRE sequences.
Conclusions:
- DWI b(0) images are less sensitive than GRE for detecting minimally hemorrhagic infarcts and small chronic hemorrhages.
- GRE sequences are superior for hemorrhage detection in emergency brain MR studies.
- Inclusion of GRE sequences is recommended for acute infarction evaluation, particularly when thrombolytic therapy is planned.