Optimizing ultrasound evaluation of carotid artery stenosis in Takayasu's Arteritis: a focus on residual inner diameter as a key parameter.

Objectives: Takayasu's arteritis (TAK) is a chronic inflammatory disease that often leads to stenosis or occlusion of the common carotid artery (CCA), posing significant risks such as stroke and cognitive impairment. Despite the widespread use of ultrasound in diagnosing and monitoring TAK, the lack of standardized criteria for assessing CCA stenosis has resulted in inconsistent evaluations. This study aims to establish standardized ultrasound diagnostic criteria for CCA stenosis in TAK, focusing on residual inner diameter and wall thickness.

Method: A total of 68 TAK patients with 120 CCAs and 120 healthy CCAs controls were included. Ultrasound examinations were performed using the iU22 Philips Healthcare system, with measurements of arterial wall thickness, inner and outer diameters, and carotid blood flow velocity. Head and neck computed tomography angiography (CTA) served as the gold standard for stenosis assessment. Statistical analyses were conducted to evaluate the diagnostic performance of various ultrasound parameters.

Results: The study found that the residual inner diameter was the most reliable parameter for assessing CCA stenosis, with high diagnostic accuracy across all stenosis categories (ROC values of 0.901 for ≥ 50% and 0.969 for ≥ 70% stenosis). Cutoff values for the residual inner diameter were established at ≤ 0.505 cm for < 50% stenosis, ≤ 0.315 cm for ≥ 50% stenosis, and ≤ 0.285 cm for ≥ 70% stenosis, achieving high sensitivity and specificity. Wall thickness and the inner-to-outer diameter ratio were effective for identifying mild stenosis but showed declining accuracy with increasing stenosis severity.

Conclusions: In conclusion, this study provides standardized ultrasound diagnostic criteria for CCA stenosis in TAK, with the residual inner diameter emerging as the most reliable parameter. These findings have significant clinical implications for improving diagnostic accuracy, guiding treatment decisions, and monitoring disease progression in TAK patients. Future research should focus on validating these criteria in larger, multicenter studies to further enhance the management of TAK. Key Points • This study establishes residual inner diameteras the most reliable ultrasound parameter for assessing carotid artery stenosis in TAK, with high diagnostic accuracy across all stenosis categories. • Residual inner diameter demonstrated exceptional diagnostic superiority in evaluating carotid stenosis, particularly for moderate-to-severe cases. Its validated cutoff values achieved high sensitivity and specificity, aligning closely with CTA results. By providing clear, reproducible thresholds, residual inner diameter minimizes misdiagnosis and underdetection of high-risk stenosis.