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MR diagnosis of subacute and chronic subarachnoid hemorrhage: comparison with CT
1Department of Radiology and Nuclear Medicine, Research Institute of Brain and Blood Vessels-Akita, Japan.
Objective:
The purpose of our study was to compare the value of MR imaging with CT in the diagnosis of subarachnoid hemorrhage in the subacute and chronic stages (> 3 days after the hemorrhagic episode).
Materials And Methods:
We performed 42 MR examinations using a 0.5-T unit in 37 patients with subarachnoid hemorrhage caused by a ruptured aneurysm. Examinations were done 4-75 days after the ictus. We obtained 40 T1-weighted, 11 proton density-weighted, 15 T2-weighted, and 28 moderately T2-weighted images. CT was also performed in all patients within 24 hr of the MR examination. Confirmation of the presence of subarachnoid hemorrhage at the time of the MR examination was made by CSF examination using lumbar puncture or surgical findings.
Results:
In the subacute and chronic stages, subarachnoid hemorrhage was seen as an area of high signal intensity on T1-weighted, proton density-weighted, T2-weighted, and moderately T2-weighted MR images in 63%, 90%, 25%, and 92% of cases, respectively. On CT scans, subarachnoid hemorrhage was seen as an area of high attenuation in only 46% of cases. Especially in the chronic stage, subarachnoid hemorrhage was seen as an area of high signal intensity more frequently by MR imaging than by CT (90% on T1-weighted images; 100% on proton density-weighted images; 25% on T2-weighted images; 100% on moderately T2-weighted images; and 10% on CT scans). High-signal-intensity subarachnoid hemorrhage was demonstrated by MR imaging until a maximum of 39 days after the ictus, whereas high-attenuation subarachnoid hemorrhage was demonstrated by CT until a maximum of 17 days after the ictus.
Conclusions:
Our findings show that MR imaging is superior to CT for the diagnosis of subacute and chronic subarachnoid hemorrhage. MR imaging is especially useful for the diagnosis of chronic subarachnoid hemorrhage.
Insights
Magnetic Resonance (MR) imaging is more effective than Computed Tomography (CT) for diagnosing subarachnoid hemorrhage in subacute and chronic stages. MR imaging offers superior visualization of subarachnoid hemorrhage, particularly in chronic cases.
Area of Science:
- Neuroradiology
- Medical Imaging
Background:
- Subarachnoid hemorrhage (SAH) diagnosis can be challenging in subacute and chronic stages (>3 days post-ictus).
- Conventional Computed Tomography (CT) has limitations in detecting SAH beyond the acute phase.
Purpose of the Study:
- To compare the diagnostic value of Magnetic Resonance (MR) imaging versus CT for subarachnoid hemorrhage in subacute and chronic stages.
- To evaluate the efficacy of different MR imaging sequences in detecting SAH.
Main Methods:
- 37 patients with confirmed subarachnoid hemorrhage underwent 42 MR examinations (0.5-T) and CT scans.
- MR imaging included T1-weighted, proton density-weighted, T2-weighted, and moderately T2-weighted sequences.
- SAH confirmation was established via cerebrospinal fluid (CSF) examination or surgical findings.
Main Results:
- MR imaging detected subarachnoid hemorrhage in 63-92% of subacute/chronic cases across different sequences, significantly higher than CT (46%).
- Proton density-weighted and moderately T2-weighted MR images showed the highest detection rates (90-92%).
- MR imaging visualized SAH up to 39 days post-ictus, while CT visualization was limited to 17 days.
Conclusions:
- MR imaging demonstrates superior performance compared to CT for diagnosing subacute and chronic subarachnoid hemorrhage.
- MR imaging, particularly with proton density-weighted and moderately T2-weighted sequences, is highly valuable for detecting chronic subarachnoid hemorrhage.