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--- hypoperfusion_intensity_ratio [2025/07/10 20:20] – [Hypoperfusion intensity ratio] administrador
+++ hypoperfusion_intensity_ratio [2025/07/10 20:23] (current) – administrador
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-====== Hypoperfusion intensity ratio ======
+====== Hypoperfusion Intensity Ratio (HIR) ======
-In a [[retrospective cohort study]]
+**Hypoperfusion Intensity Ratio (HIR)** is a cerebral perfusion imaging biomarker used in acute ischemic stroke to quantify the severity of hypoperfusion and assess collateral blood flow.
-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
-((Asimos AW, Yang H, Strong D, Teli KJ, Clemente JD, DeFilipp G, Bernard J, Stetler W, Parish JM, Hines A, Rhoten JB, Karamchandani RR. Association of [[hypoperfusion intensity ratio]] and [[cerebral blood volume Index]] with good [[outcome]] in patients transferred for [[thrombectomy]]. Interv Neuroradiol. 2025 Jul 10:15910199251352046. doi: 10.1177/15910199251352046. Epub ahead of print. PMID: 40638076.)).
-==== Critical Review ====
+===== Definition =====
+**HIR = Volume of tissue with Tmax >10 seconds / Volume of tissue with Tmax >6 seconds**
-Strengths
+  * **Tmax >6 sec**: represents all hypoperfused tissue (potentially salvageable penumbra).
+  * **Tmax >10 sec**: represents severely hypoperfused tissue (more likely to become infarct core).
-Excellent [[sample size]] (n = 497), with high treatment prevalence (93% thrombectomy) supporting real-world relevance.
+===== Interpretation =====
+  * **High HIR (~1)**:
+    * A large portion of hypoperfused tissue is severely delayed.
+    * Indicates poor collateral flow.
+    * Associated with greater infarct growth and worse clinical outcome.
-Rigorous adjustment for confounders in multivariable models enhances validity.
+  * **Low HIR (~0)**:
+    * Most of the hypoperfused tissue has only moderate delay.
+    * Suggests good collateral circulation.
+    * Associated with better response to reperfusion therapies.
-Weaknesses
+===== Clinical Relevance =====
+HIR is used alongside other imaging parameters (CBF, CBV, core/penumbra mismatch) to:
+  * Predict infarct growth and clinical outcomes.
+  * Select patients for endovascular therapy in extended time windows (e.g., DEFUSE 3, DAWN).
+  * Guide treatment decisions when standard time-based criteria are insufficient.
-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.
-==== Final Verdict ====
-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