Blood-Brain Barrier Permeability Assessed by Perfusion CT Predicts Symptomatic Hemorrhagic Transformation and Malignant Edema in Acute Ischemic Stroke

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Fig 1.
A 75-year-old woman was admitted to the emergency department with a right hemiparesis. She underwent stroke CT imaging work-up approximately 2 hours after symptom onset. NCCT revealed no evidence of intracranial hemorrhage, and she was treated with IV tPA at this time. Twenty-three hours later, she was in critical condition in the intensive care unit, and imaging follow-up at that time demonstrated development of PH-2. There are 2 red arrows—1 on the admission permeability map and 1 on the follow-up NCCT. The red arrows indicate that the patient presented with a “hotspot” (a sizable volume of abnormally elevated permeability on the baseline PCT study); this hotspot was centered in the same place as a focus of significant hemorrhage in the patient's eventual PH-2. Of note, permeability hotspots (voxels with absolute permeability >5 mL/100 g/min that are delineated in blue automatically by the software) occur in both the infarct and penumbra, not just in the infarct, where the vasculature has presumably undergone the most severe ischemia-induced damage. Thus, permeability imaging provides information above and beyond what is provided by the standard PCT parameters that can be used to define infarct and penumbra.

Table 1:

Study patient characteristics (N = 32)

Characteristic	Data
No. of men (%)	13 (41%)
Age (yr)	Median = 72
	Interquartile range = 64.75–85.25
	Range = 46–96
Time from stroke onset to admission imaging (hr)	Median = 2
	Interquartile range = 1.5–4.1
	Range = 1–12
Time from admission imaging to follow-up imaging to assess recanalization, reperfusion, and hemorrhagic transformation (hr)	Median = 24.8
	Interquartile range = 22.5–27.25
	Range = 4.75–75
Admission NIHSS	Median = 14
	Interquartile range = 10–17
	Range = 3–21
24-hour NIHSS	Median = 9
	Interquartile range = 4–14
	Range = 1–21
Discharge NIHSS	Median = 4
	Interquartile range = 2–10
	Range = 1–17
Stroke location
ACA and MCA territories	0
MCA territory	32
ACA territory	0
PCA territory	0
Admission mean volume of CBV abnormality, considered equivalent to infarct core (mean in mL)	31.7 ± 33.1
Admission mean volume of MTT abnormality (mean in mL)	110.3 ± 59.2
Admission mean volume of penumbra, defined by MTT-CBV mismatch (mean in mL)	78.6 ± 43.3
MTT index of reperfusion (%)	56 ± 40

Table 2:

Univariate analysis of clinical and imaging predictors of significant clinical deterioration

	Univariate Analysis (N= 32)
	OR	P Value	Area Under the Curve
Clinical Variables
Age	1.07	.08^a	72.8%
Current antiplatelet (aspirin and/or clopidogrel) therapy	0	.007^a	80.8%
Current warfarin therapy	0	.25	40.4%
Admission INR	.34	.703	54.8%
Admission NIHSS	1.26	.07^a	73.1%
Time from symptom onset to scanning	.81	.43	52.6%
tPA treatment	>1000	.03^a	67.3%
Merci treatment	.68	.68	54.5%
Imaging variables
Admission PCT-defined infarct volume	1.02	.08^a	63.5%
Admission BBBP	1.71	.01^a	79.6%
Collaterals to the region of the stroke	.37	.29	61.5%
Recanalization	.46	.41	59.4%
Reperfusion	.62	.003^a	82.1%