Spontaneous intracerebral hemorrhage remains one of the deadliest forms of acute stroke worldwide. Consequently, early risk stratification is essential to prevent secondary brain injury and improve clinical outcomes. The detection of a multiphase CTA spot sign provides critical prognostic insight into dynamic active bleeding within the brain parenchyma. By identifying contrast extravasation across multiple arterial and venous phases, clinicians can rapidly anticipate hematoma expansion, personalize acute management, and tailor emergency neurocritical therapies.

Value of the Multiphase CTA Spot Sign in Acute Stroke

Acute intracerebral hemorrhage causes rapid clinical deterioration in nearly one-third of admitted patients. Historically, emergency stroke teams relied on conventional single-phase computed tomography angiography to detect active extravasation. However, single-phase scans capture only a fleeting snapshot during early arterial contrast enhancement. As a result, standard imaging protocols frequently miss slower or delayed microvascular contrast leakage within the expanding hematoma cavity. Multiphase computed tomography angiography effectively overcomes this diagnostic limitation by scanning across three distinct time points without requiring additional contrast injections. Specifically, the imaging sequence records an initial arterial phase followed immediately by two successive venous and delayed phases. Therefore, this dynamic protocol captures persistent contrast pooling that evolves gradually over several seconds. Clinical teams in emergency and neurocritical care units gain superior diagnostic clarity regarding active microvascular rupture. Furthermore, promptly recognizing ongoing hemorrhage enables timely blood pressure control, swift hemostatic resuscitation, and rapid reversal of coagulopathy. Because hematoma expansion directly correlates with neurological worsening and increased 30-day mortality, accurate early identification remains paramount. Ultimately, multiphase neurovascular imaging shifts acute stroke assessment from a static snapshot toward a dynamic physiological evaluation.

Findings from the Karolinska University Hospital Study

A landmark observational cohort study conducted at Karolinska University Hospital recently evaluated 159 patients presenting with acute spontaneous intracerebral hemorrhage. Researchers analyzed admission non-contrast computed tomography, standardized multiphase vascular imaging, and follow-up imaging completed within 72 hours. Overall, investigators detected a contrast focus in 88 out of 159 individuals, establishing a robust 55 percent detection rate. Interestingly, the timing of spot sign appearance varied dramatically across the consecutive imaging phases. Fifty-one patients demonstrated extravasation during the initial arterial phase. However, an additional 28 patients showed contrast leakage only during the second phase, while nine individuals displayed signs exclusively in the third phase. Consequently, conventional single-phase imaging would have completely missed 42 percent of all active bleeders in this cohort. More importantly, the incidence of hematoma enlargement remained remarkably consistent regardless of appearance timing. Among patients with markers appearing in phases one, two, and three, hematoma expansion occurred in 49 percent, 46 percent, and 44 percent, respectively. In contrast, patients lacking these markers experienced hematoma expansion in only 17 percent of cases. Hence, delayed visualization identifies an equally vulnerable cohort destined for poor functional recovery.

Quantitative Characteristics and Dynamic Evolution of Contrast Spots

Beyond mere detection, quantitative characteristics provide vital clues regarding acute hemorrhage behavior. The investigators meticulously examined the physical dimensions, radiographic density, and morphological growth of contrast extravasation across consecutive scanning phases. In patients who suffered substantial hematoma expansion, contrast spots were consistently larger, denser, and more numerous upon initial presentation. Moreover, monitoring the temporal progression between sequential phases yielded powerful predictive insights. When patients exhibited an interval increase in spot volume, spot count, or attenuation values, their risk of hematoma growth escalated significantly. This dynamic enlargement indicates robust microvascular breakdown with sustained high-flow or continuous low-flow bleeding into surrounding parenchymal tissue. Conversely, stable or rapidly dissipating spots often reflect self-limiting rupture that tamponades spontaneously. In daily clinical practice, measuring attenuation changes in Hounsfield units allows neuroradiologists to differentiate genuine extravasation from calcification, aneurysm remnants, or background artifact. In addition, tracking volumetric expansion across delayed phases helps multidisciplinary teams distinguish passive interstitial diffusion from true persistent hemorrhage. Consequently, dynamic multiphase parameters transform simple visual identification into a quantitative vascular biomarker that refines clinical decision-making.

Translating Imaging Biomarkers into Neurocritical Management

Predicting hematoma expansion is clinically vital because active growth represents the single most important modifiable predictor of neurological disability after intracerebral hemorrhage. Once clinicians identify active contrast extravasation, they must initiate aggressive medical stabilization immediately. For example, international stroke guidelines emphasize rapid blood pressure reduction to prevent hydrostatic pressure from driving further intraparenchymal bleeding. Similarly, physicians must promptly administer specific reversal agents for patients receiving vitamin K antagonists or direct oral anticoagulants. In cases where patients show progressive spot enlargement across delayed phases, clinicians should consider early intensive care admission and urgent neurosurgical consultation. Emerging minimally invasive surgical techniques and endoscopic evacuations also depend heavily on precise bleeding localization and dynamic timing. Furthermore, randomized clinical trials investigating novel hemostatic therapies have historically struggled with patient selection. Enrolling unselected patients frequently led to neutral trial outcomes because stable non-expanders diluted therapeutic benefits. Therefore, incorporating multiphase vascular protocols into emergency triage ensures that aggressive hemostatic treatments target individuals who will benefit most. By enriching patient cohorts with confirmed active bleeders, clinical teams can maximize therapeutic efficacy while minimizing unnecessary exposure to thrombotic risks.

Optimizing Protocols for Emergency and Radiology Departments

Implementing multiphase computed tomography angiography into routine emergency stroke pathways requires minimal additional hospital resources. Modern multi-detector computed tomography scanners can automatically acquire sequential phases without moving the patient or administering additional iodinated contrast doses. Specifically, a single standardized contrast bolus supplies adequate vascular opacification for the arterial phase and subsequent delayed recordings. As a result, the entire protocol adds less than two minutes to the emergency imaging evaluation while delivering substantial diagnostic gains. Although the additional scanning phases impart a minor increase in radiation dose, the clinical benefit of preventing devastating hematoma expansion far outweighs this modest exposure. In emergency triage centers across India and globally, establishing standardized stroke imaging algorithms facilitates seamless communication between radiologists, emergency physicians, and neurosurgeons. Additionally, rapid automated post-processing software and artificial intelligence tools can instantly quantify spot volumes and attenuation changes, expediting critical alerts to neurointensive care teams. Thus, adopting multiphase neurovascular imaging elevates acute stroke triage from basic diagnostic confirmation to sophisticated, personalized risk stratification.

What is the clinical significance of a spot sign on multiphase CTA?

The spot sign represents active contrast extravasation from ruptured microvessels directly into an evolving intracerebral hematoma. When detected on multiphase CTA, it signifies ongoing bleeding and indicates a high risk of subsequent hematoma expansion. Because multiphase imaging captures delayed venous phases, it identifies delayed extravasation that standard single-phase protocols overlook. Consequently, recognizing this sign enables acute stroke teams to initiate rapid blood pressure reduction and urgent hemostatic interventions without delay.

Why does single-phase CTA miss delayed contrast extravasation in ICH?

Single-phase CTA acquires images exclusively during the initial arterial peak to evaluate major vessel occlusions and vascular malformations. However, active bleeding within brain parenchyma often occurs through small, high-resistance arterioles or damaged capillary beds with slow flow rates. As a result, contrast accumulation frequently requires extra time to become radiographically visible. Multiphase protocols capture subsequent delayed phases, thereby uncovering slower contrast extravasation that would otherwise remain entirely undetected during early arterial acquisition.

How does spot sign evolution across phases guide patient management?

Dynamic changes across multiphase acquisitions provide critical prognostic details regarding bleeding velocity. When contrast foci increase in size, radiographic density, or total number between sequential phases, patients face an exceedingly high probability of clinical deterioration. Therefore, neurocritical teams use this dynamic evolution to prioritize intensive neurological monitoring, aggressive hemodynamic control, and urgent reversal of anticoagulation. In selected situations, neurosurgeons also utilize these progression patterns to guide timely surgical evacuation or minimally invasive interventions.

Disclaimer: This content is for informational and educational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Refer to the latest local and national guidelines for clinical practice.

References

1. Almqvist T et al. Utility of the Spot Sign on Multiphase CT Angiography for Prediction of Hematoma Expansion in Intracerebral Hemorrhage. AJNR Am J Neuroradiol. 2026 Sep 23. doi: undefined. PMID: 42778500.


2. Rodríguez-Luna D, et al. Multiphase CT Angiography Improves Prediction of Intracerebral Hemorrhage Expansion. Radiology. 2017;285(3):893-900.


3. Demchuk AM, et al. Spot sign selection for acute hemostatic therapy in intracerebral hemorrhage: critical reappraisal and future clinical implications. Stroke. 2025;56(4):1012-1021.