Multiple Thresholds for Different Components of the Brain in Ischemic Stroke Perfusion Imaging
Background
The treatment target for acute ischemic stroke is to open the occluded blood vessel with thrombolysis. By opening the occluded vessel we can save the tissues at risk of conversion to infarct core which referred to as the penumbra. Nowadays with advanced imaging, clinicians are able to distinguish the penumbra and infarct core.
If the penumbra is large and infarct core small (mismatch ratio>1.2, Mismatch ratio=ischemic lesion volume / infarct core volume), clinical trials of imaging selected patients have shown that thrombolysis administration with the aim of restoring the blood flow (reperfusion) to the penumbra improves patient?s clinical …show more content…
The following diagram will show these 3 interrelated steps.
Step 1: investigate the absolute perfusion values of infarct core and penumbra in grey matter and white matter separately.
Aim: validate grey matter has higher CBV and CBF, but shorter MTT compare to white matter in physiological status and under ischemic condition, in CT perfusion imaging.
Methodology:
Patients
A cohort of 82 acute hemisphere ischemic stroke patients who were admitted to the John Hunter hospital database will be enrolled in the studies. All Patients will undergo acute multimodal CT (NCCT, CTP and CTA) and DWI on admission, and follow by 24 hour MR sequence. Patients without reperfusion will be included into the group investigate penumbra absolute perfusion value.
Criteria for patients without reperfusion: reduction in MTT lesion volume in 24-h perfusion scan less than 20% compare to acute perfusion imaging [1, 2].
Clinical assessments were performed on all patients acutely, at 24 hours and at 90 days post stroke by a certified neurologist or neurology registrar. Clinical assessments included the National Institutes of Health Stroke Scale (NIHSS), and a modified Rankin Score …show more content…
The DWI image is considered to be the ?true? lesion. Lesions overlap in DWI and CTP will be considered as True Positive (TP); lesions in CTP but not included in DWI will be considered as False Positive (FP); pixel not including in CTP either DWI will be considered as True Negative (TN); lesions in DWI but not included in CTP will be considered as False Negative (FN). Sensitivity [TP/ (TP+FN)] and specificity [TN/ (TN+FP)] will be calculated for each perfusion maps. Sensitivity, specificity, positive predictive and negative predictive value will be calculated for each threshold increment. Overall accuracy for each threshold will be calculated as AUC (and 95%
Background
The treatment target for acute ischemic stroke is to open the occluded blood vessel with thrombolysis. By opening the occluded vessel we can save the tissues at risk of conversion to infarct core which referred to as the penumbra. Nowadays with advanced imaging, clinicians are able to distinguish the penumbra and infarct core.
If the penumbra is large and infarct core small (mismatch ratio>1.2, Mismatch ratio=ischemic lesion volume / infarct core volume), clinical trials of imaging selected patients have shown that thrombolysis administration with the aim of restoring the blood flow (reperfusion) to the penumbra improves patient?s clinical …show more content…
The following diagram will show these 3 interrelated steps.
Step 1: investigate the absolute perfusion values of infarct core and penumbra in grey matter and white matter separately.
Aim: validate grey matter has higher CBV and CBF, but shorter MTT compare to white matter in physiological status and under ischemic condition, in CT perfusion imaging.
Methodology:
Patients
A cohort of 82 acute hemisphere ischemic stroke patients who were admitted to the John Hunter hospital database will be enrolled in the studies. All Patients will undergo acute multimodal CT (NCCT, CTP and CTA) and DWI on admission, and follow by 24 hour MR sequence. Patients without reperfusion will be included into the group investigate penumbra absolute perfusion value.
Criteria for patients without reperfusion: reduction in MTT lesion volume in 24-h perfusion scan less than 20% compare to acute perfusion imaging [1, 2].
Clinical assessments were performed on all patients acutely, at 24 hours and at 90 days post stroke by a certified neurologist or neurology registrar. Clinical assessments included the National Institutes of Health Stroke Scale (NIHSS), and a modified Rankin Score …show more content…
The DWI image is considered to be the ?true? lesion. Lesions overlap in DWI and CTP will be considered as True Positive (TP); lesions in CTP but not included in DWI will be considered as False Positive (FP); pixel not including in CTP either DWI will be considered as True Negative (TN); lesions in DWI but not included in CTP will be considered as False Negative (FN). Sensitivity [TP/ (TP+FN)] and specificity [TN/ (TN+FP)] will be calculated for each perfusion maps. Sensitivity, specificity, positive predictive and negative predictive value will be calculated for each threshold increment. Overall accuracy for each threshold will be calculated as AUC (and 95%