RCVS Score: Clinical Indicators and Neuroimaging Criteria

Reversible cerebral vasoconstriction syndrome (RCVS) is marked by transient narrowing of cerebral arteries, often leading to severe headaches and potential neurological complications. Early diagnosis is crucial, as timely intervention can reduce the risk of stroke or long-term effects. Given its overlap with other cerebrovascular disorders, clinical scoring systems have been developed to improve diagnostic accuracy.

RCVS scores integrate clinical indicators and neuroimaging findings to aid recognition and differentiation from similar conditions. Understanding these components is essential for guiding treatment decisions.

Common Clinical Indicators

RCVS typically presents with a sudden, severe “thunderclap” headache that peaks within seconds. This headache is often mistaken for a sentinel bleed in subarachnoid hemorrhage but differs from migraines, which develop gradually and may include aura. Over 90% of RCVS patients experience recurrent thunderclap headaches, making them a key diagnostic feature (Calabrese et al., 2007).

Precipitating factors provide further diagnostic clues. RCVS is frequently triggered by vasoactive substances, including serotonergic antidepressants, adrenergic stimulants, cannabis, and certain nasal decongestants. Postpartum women are at increased risk, particularly within weeks after delivery, likely due to hormonal fluctuations affecting vascular tone. A Stroke (2020) study found that nearly 60% of RCVS cases had an identifiable trigger, emphasizing the importance of a thorough patient history.

Neurological deficits, though often transient, complicate diagnosis. Some patients experience focal symptoms such as hemiparesis, dysphasia, or visual disturbances, mimicking transient ischemic attacks (TIAs) or early-stage stroke. Seizures occur in about 10-15% of cases, particularly in severe vasoconstriction. These deficits stem from reversible hypoperfusion rather than permanent infarction, distinguishing RCVS from other cerebrovascular disorders.

Neuroimaging Criteria

Neuroimaging plays a critical role in confirming arterial abnormalities and ruling out alternative diagnoses. The hallmark radiologic feature of RCVS is segmental vasoconstriction in cerebral arteries, visible on catheter-based cerebral angiography, computed tomography angiography (CTA), and magnetic resonance angiography (MRA). These modalities often reveal a “string of beads” appearance, reflecting the transient nature of vasospasm.

The sensitivity of angiographic studies varies with timing. Vasoconstriction may not appear in early imaging, leading to potential false negatives. A Neurology (2019) study found that initial angiography failed to detect vasospasm in about 30% of RCVS cases, underscoring the need for serial imaging when clinical suspicion is high. Follow-up studies one to two weeks later often reveal progressive narrowing before resolution, distinguishing RCVS from non-reversible vasculopathies like primary angiitis of the central nervous system (PACNS).

High-resolution vessel wall MRI (VW-MRI) helps differentiate RCVS from inflammatory vasculopathies. Unlike PACNS, which shows arterial wall enhancement due to inflammation, RCVS typically lacks such enhancement. Diffusion-weighted imaging (DWI) assesses the impact of vasoconstriction on cerebral perfusion. While most RCVS cases do not result in permanent infarction, severe cases can lead to watershed infarcts. A Stroke (2021) analysis found that about 20% of RCVS patients had ischemic lesions on DWI, often in border-zone regions, highlighting the need for early intervention.

Methods of Score Calculation

RCVS scoring systems integrate clinical and radiologic data to stratify patients by likelihood of the condition. These models assign weighted values to key features, improving diagnostic confidence.

Headache characteristics play a significant role, particularly recurrent thunderclap headaches. A known trigger, such as vasoactive substance exposure or recent pregnancy, increases the score. Neurological deficits, when consistent with reversible hypoperfusion, contribute additional points.

Neuroimaging findings are also heavily weighted, with angiographic evidence of segmental vasoconstriction being a key criterion. Serial imaging showing progression followed by resolution strengthens the diagnosis. High-resolution vessel wall MRI refines scoring by distinguishing RCVS from inflammatory vasculopathies. The absence of infarction on diffusion-weighted imaging further supports the diagnosis.

Interpreting Diagnostic Findings

Interpreting an RCVS score requires assessing clinical and imaging data collectively. While thunderclap headaches or segmental vasoconstriction are suggestive, their diagnostic value increases when considered together. A high score does not confirm RCVS outright but indicates a strong probability requiring further evaluation.

Temporal patterns in imaging findings are crucial. Unlike progressive vasculopathies, RCVS follows a course where arterial constriction peaks before resolving within weeks. Serial imaging captures this evolution, reinforcing the diagnosis when follow-up studies show improvement without intervention. This dynamic progression distinguishes RCVS from PACNS or intracranial atherosclerosis, which typically show persistent abnormalities. The absence of vessel wall enhancement on high-resolution MRI further supports RCVS.

Conditions That May Overlap

Several conditions share clinical and imaging similarities with RCVS, requiring careful evaluation to avoid misdiagnosis. While RCVS features transient arterial narrowing with a self-limiting course, other conditions may present with persistent vascular abnormalities, inflammation, or irreversible ischemic damage.

Primary angiitis of the central nervous system (PACNS) is a key diagnostic mimic, as both conditions involve multifocal arterial narrowing. However, PACNS is an inflammatory vasculitis, typically showing vessel wall enhancement on high-resolution MRI. Unlike RCVS, which resolves spontaneously, PACNS progresses if untreated and often requires immunosuppressive therapy. Cerebral angiography alone cannot reliably differentiate these disorders, making cerebrospinal fluid (CSF) analysis valuable. Elevated protein levels and pleocytosis in CSF suggest PACNS, whereas RCVS lacks inflammatory markers. Misidentifying PACNS as RCVS can delay immunosuppressive treatment, increasing the risk of neurological damage.

Subarachnoid hemorrhage (SAH) also shares features with RCVS, particularly sudden thunderclap headaches. While SAH results from aneurysmal rupture and blood extravasation, RCVS headaches stem from transient vasospasm. Non-contrast CT distinguishes these conditions, as SAH presents with hyperdense blood accumulation, whereas RCVS typically lacks acute hemorrhage. However, RCVS can be complicated by convexity SAH, a benign variant with small cortical hemorrhages. The presence of isolated convexity SAH in a patient with recurrent thunderclap headaches should prompt consideration of RCVS rather than aneurysmal rupture.

Posterior reversible encephalopathy syndrome (PRES) may coexist with RCVS, complicating differentiation. PRES manifests with vasogenic edema on MRI, predominantly in the parieto-occipital regions, and is often associated with hypertension or eclampsia. Recognizing these overlapping conditions requires a comprehensive assessment of clinical history, imaging patterns, and laboratory markers to ensure accurate diagnosis and appropriate management.