Acute subarachnoid blood is difficult to differentiate from CSF on most MRI sequences and therefore MRI is not as good as CT for the initial diagnosis. Within 24-48 hours of SAH, there is too little methemoglobin for hemorrhage to be obvious, especially with the small amount of blood often involved. Visualization of blood on MRI is, however, better after 4-7 days and is therefore excellent at demonstrating subacute to remote SAH at 10-20 days, when CT sensitivity decreases.
Magnetic resonance angiography reveals most aneurysms that are greater than 3 mm in diameter. The sensitivity for identification of aneurysms is 85-90%, with a specificity of greater than 90% when compared with DSA , with an excellent intra-observer consistency and good-to-excellent inter-observer repro-ducibility.
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The term vaginitis is one that is applied to any inflammation or infection of the vagina, and there are many different conditions that are categorized together under this ‘broad’ heading, including bacterial vaginosis, trichomoniasis and non-infectious vaginitis.