Lesion Water Content on CT Predicts 12-Month Outcome and Modifies Thrombectomy Effect in Large-Core Stroke-A Secondary Analysis of the TENSION Trial.

```mdx

title: "Lesion Water Content on CT Predicts Stroke Outcome After Thrombectomy"

description: "A secondary analysis of the TENSION trial finds that net water uptake on noncontrast CT predicts 12-month functional outcome in large-core stroke and modifies the benefit of thrombectomy."

study_type: "Randomized controlled trial (secondary analysis)"

sample_size: 198

journal: "Translational Stroke Research"

pubmed_id: "42909781"

TL;DR

In large-core ischemic stroke, the amount of water inside the damaged brain tissue on a standard CT scan predicted 12-month functional outcome and changed how much patients benefited from thrombectomy. This is a secondary analysis of a randomized trial, so it generates a hypothesis for prospective confirmation rather than a clinical rule.

What the study found

Large-core strokes, where a major blood clot blocks a large portion of the brain's blood supply, remain difficult to predict even after endovascular thrombectomy (EVT), a procedure that mechanically removes the clot. Lesion size alone explains only part of the variation in outcomes. The authors asked whether the water content of the injured tissue, measured on noncontrast CT and expressed as net water uptake (NWU), could capture additional, treatment-relevant injury.

The analysis included 198 patients from the TENSION trial who had a usable admission CT and a 12-month modified Rankin Scale (mRS) score, a standard measure of disability where lower scores indicate better function. Of these, 168 also had a 24-hour follow-up CT, allowing the team to calculate follow-up net water uptake (NWUFU). The median baseline NWU was 16.4%, and the median NWUFU was 28.9%. At 12 months, 23% of patients had an mRS of 0 to 3, indicating independent or near-independent function, and 56% had died.

Higher baseline NWU independently predicted worse 12-month disability after adjustment for other factors (adjusted common odds ratio 1.10 per percentage point; 95% CI 1.05 to 1.16; P below 0.001). Notably, baseline NWU also modified the effect of EVT. The interaction term was statistically significant (adjusted common odds ratio 1.17; 95% CI 1.06 to 1.30; P = 0.002), suggesting that the relative benefit of thrombectomy varied with the degree of baseline water uptake. In terms of discrimination, baseline NWU outperformed ASPECTS, a widely used visual CT scoring system for early ischemic change.

The strongest single imaging predictor was the follow-up measurement. NWUFU independently predicted 12-month outcome (adjusted common odds ratio 1.10; 95% CI 1.06 to 1.14; P below 0.001), with an area under the receiver operating characteristic curve of 0.78 for achieving mRS 0 to 3. When both measures were modeled together, NWUFU superseded baseline NWU. Among the 97 patients who survived to 90 days, higher NWUFU also independently predicted later mortality (adjusted odds ratio 1.09; 95% CI 1.02 to 1.18; P = 0.019).

These findings are internally consistent, but they come from a secondary analysis, not a trial designed to test NWU as a predictor. The threshold values, the interaction result, and the discrimination comparisons all need replication in an independent cohort before they can guide individual decisions. The authors also describe the approach as a possible bridge between treatment-modifiable injury at baseline and the injury that actually develops after treatment, but this interpretation is a hypothesis the data are consistent with rather than proof of mechanism.

What this means for you

If you or a family member has had a large-core stroke, the practical implications of this study are limited for now. Treatment decisions rest on established clinical criteria and imaging assessment by the treating team, and NWU is not yet part of routine practice. What the study offers is a direction for better prognostic tools, potentially using CT data that is already acquired in most stroke centers.

For general brain health, this research does not identify a new modifiable behavior. Stroke risk reduction remains tied to well-established factors such as blood pressure control, smoking cessation, regular physical activity, and a high-fiber diet. No supplement has been shown in this study to influence stroke outcomes, and none should be considered a substitute for emergency treatment. If stroke symptoms appear, such as sudden facial droop, arm weakness, or speech difficulty, seek emergency care immediately.

Study details

Sources

1. Lesion Water Content on CT Predicts 12-Month Outcome and Modifies Thrombectomy Effect in Large-Core Stroke: A Secondary Analysis of the TENSION Trial. *Translational Stroke Research*. PubMed. https://pubmed.ncbi.nlm.nih.gov/42909781/

```