Quantification of clot spatial heterogeneity and its impact on thrombectomy

UMMS Affiliation

Department of Radiology, New England Center for Stroke Research

Publication Date


Document Type



Cardiovascular Diseases | Nervous System Diseases | Neurology | Neurosurgery | Radiology


BACKGROUND: Compositional and structural features of retrieved clots by thrombectomy can provide insight into improving the endovascular treatment of ischemic stroke. Currently, histological analysis is limited to quantification of compositions and qualitative description of the clot structure. We hypothesized that heterogeneous clots would be prone to poorer recanalization rates and performed a quantitative analysis to test this hypothesis.

METHODS: We collected and did histology on clots retrieved by mechanical thrombectomy from 157 stroke cases (107 achieved first-pass effect (FPE) and 50 did not). Using an in-house algorithm, the scanned images were divided into grids (with sizes of 0.2, 0.3, 0.4, 0.5, and 0.6 mm) and the extent of non-uniformity of RBC distribution was computed using the proposed spatial heterogeneity index (SHI). Finally, we validated the clinical significance of clot heterogeneity using the Mann-Whitney test and an artificial neural network (ANN) model.

RESULTS: For cases with FPE, SHI values were smaller (0.033 vs 0.039 for grid size of 0.4 mm, P=0.028) compared with those without. In comparison, the clot composition was not statistically different between those two groups. From the ANN model, clot heterogeneity was the most important factor, followed by fibrin content, thrombectomy techniques, red blood cell content, clot area, platelet content, etiology, and admission of intravenous tissue plasminogen activator (IV-tPA). No statistical difference of clot heterogeneity was found for different etiologies, thrombectomy techniques, and IV-tPA administration.

CONCLUSIONS: Clot heterogeneity can affect the clot response to thrombectomy devices and is associated with lower FPE. SHI can be a useful metric to quantify clot heterogeneity.


intervention, stroke, technology, thrombectomy

DOI of Published Version



Liu Y, Brinjikji W, Abbasi M, Dai D, Arturo Larco JL, Madhani SI, Shahid AH, Mereuta OM, Nogueira RG, Kvamme P, Layton KF, Delgado Almandoz JE, Hanel RA, Mendes Pereira V, Almekhlafi MA, Yoo AJ, Jahromi BS, Gounis MJ, Patel B, Fitzgerald S, Doyle K, Haussen DC, Al-Bayati AR, Mohammaden M, Pisani L, Rodrigues GM, Thacker IC, Kayan Y, Copelan A, Aghaebrahim A, Sauvageau E, Demchuk AM, Bhuva P, Soomro J, Nazari P, Cantrell DR, Puri AS, Entwistle J, Kadirvel R, Cloft HJ, Kallmes DF, Savastano L. Quantification of clot spatial heterogeneity and its impact on thrombectomy. J Neurointerv Surg. 2021 Dec 15:neurintsurg-2021-018183. doi: 10.1136/neurintsurg-2021-018183. Epub ahead of print. PMID: 34911736. Link to article on publisher's site

Journal/Book/Conference Title

Journal of neurointerventional surgery


Full author list omitted for brevity. For the full list of authors, see article.

Related Resources

Link to Article in PubMed

PubMed ID