Cerebral blood volume index

• Optimal markers of treatment response to vasodilatory drugs in small vessel disease: An OxHARP Trial analysis
• Association of hypoperfusion intensity ratio and cerebral blood volume Index with good outcome in patients transferred for thrombectomy
• Integrating perfusion imaging derived venous outflow and tissue-level collateral parameters in a comprehensive clinical model enhances prognostication in large vessel occlusion stroke
• Hemodynamic assessment of rupture risk during growth stages in middle cerebral artery aneurysms treated with coiling
• Correlating retinal and choroidal vascular parameters with volumetric MRI in Alzheimer's disease and amnestic mild cognitive impairment
• Explaining tip-of-the-tongue experiences in older adults: The role of brain-based and cardiorespiratory fitness factors
• Association between Cerebral Blood Volume Index and Excellent Reperfusion in Acute Ischemic Stroke Patients Undergoing Mechanical Thrombectomy
• Effects of Proteinuria on Cerebral and Muscle Oxygenation and Microvascular Reactivity in Patients With Pre-Dialysis Chronic Kidney Disease: A Post-Hoc Analysis

Cerebral Blood Volume Index (CBVI) is a quantitative imaging biomarker used to assess the volume of blood within a given amount of brain tissue, typically expressed in milliliters of blood per 100 grams of brain tissue (mL/100g).

• CBV is an absolute perfusion metric.
• CBVI is a normalized or indexed version of CBV, designed to allow standardization across individuals or brain regions.
• CBVI improves comparability, especially in clinical trials and multi-center studies involving perfusion imaging.

Cerebral Blood Volume Index (CBVI) refers to the standardized measure of cerebral blood volume (CBV) that accounts for individual variation and allows for comparison across patients or regions. It is often normalized to a reference region (like the contralateral hemisphere or white matter) to improve reproducibility and detect pathological changes.

Derived from CT perfusion or MRI perfusion imaging.

Elevated CBVI may reflect hyperemia, luxury perfusion, or tumoral neovascularization.

Reduced CBVI may indicate ischemia, hypoperfusion, or vascular steal.

In ischemic stroke, CBVI helps delineate:

Infarct core (low CBVI, low CBF)

Penumbra (preserved CBVI, low CBF)

In brain tumors, elevated CBVI often correlates with tumor grade and angiogenesis.

CBVI is usually obtained using software that processes dynamic contrast-enhanced imaging, integrating time–concentration curves and using deconvolution algorithms to isolate the blood volume component.

In a retrospective cohort study Asimos et al. from Atrium Health, Charlotte (Emergency Medicine, Neurosciences Institute, Quality Analytics, Radiology, Neurosurgery, Neurology) published in the Interventional Neuroradiology Journal to assess whether hypoperfusion intensity ratio (HIR) and cerebral blood volume index (CBVI) measured via CT perfusion at referring non-thrombectomy centers predict favorable 90‑day outcomes post-transfer for thrombectomy in anterior circulation large vessel occlusion (ACLVO). CBVI—as a continuous measure and specifically > 0.7—correlated with functional independence (mRS ≤ 2) at 90 days both overall and in recanalized patients. In contrast, HIR thresholds and combined collateral scores were not predictive ¹⁾.

Strengths

Excellent sample size (n = 497), with high treatment prevalence (93% thrombectomy) supporting real-world relevance.

Rigorous adjustment for confounders in multivariable models enhances validity.

Weaknesses

Retrospective and single-center design at a large referral system may limit external generalizability.

No direct comparisons to other perfusion metrics like Tmax or ischemic core volumes—makes it difficult to situate CBVI within broader CTP prognostication tools.

HIR binary thresholds (0.4–0.6) may lack granularity; their univariate non-association could stem from arbitrary cutoffs rather than biological irrelevance.

Unclear reproducibility or inter-observer reliability of CBVI quantification across centers or software versions.

Statistical note

Adjusted OR of 1.73 for CBVI > 0.7 is clinically meaningful, but confidence interval (1.13–2.65) suggests moderate precision.

Rating: 6.5 / 10

Takeaway for practitioners: CBVI from CT perfusion at referring centers could offer a pragmatic predictor of functional independence after thrombectomy, especially when > 0.7. However, its standalone prognostic value remains uncertain until validated prospectively and benchmarked against established perfusion metrics.

Bottom line: CBVI appears promising as a simple, transportable predictor of favorable outcome in ACLVO, but further multi‑center, prospective validation and comparison studies are needed before adoption into routine transfer decision-making.

Categories: Retrospective Studies, Stroke Imaging, Thrombectomy Outcomes

Tags: CT perfusion, CBVI, HIR, collateral perfusion, stroke prognostication, thrombectomy, anterior circulation LVO