To the editor

We thank Dr. Christian Saleh for his interest in our recent publication¹ and his thorough analysis. We appreciate the opportunity to clarify his methodological concerns regarding carotid intima‑media thickness (cIMT) measurement.

In our study, a single experienced cardiologist performed ultrasound examinations of all carotid arteries, including cIMT assessment, in line with the Mannheim consensus. This widely accepted document outlines essential technical requirements for carotid ultrasonography, including equipment settings, imaging protocols, measurement sites, etc. While it recommends performing measurements in both common carotid arteries (CCAs), it does not mandate bilateral assessment. For transparency, we stated in our paper that measurements were taken only in the right CCA. Although the literature still debates which carotid artery and segment should be used to assess atherosclerosis progression and predict cardiovascular outcomes, many studies follow different protocols. Several meta‑analyses have highlighted these discrepancies.²

While we agree with the need to standardize cIMT measurement protocols—especially in clinical practice—we also acknowledge that clinical studies often adopt tailored protocols, particularly in specific populations. Our cohort included adults with type 1 diabetes mellitus (T1DM), at an average age of 32 years, with a mean disease duration of 14 years, and no major comorbidities. We excluded individuals with cardiovascular disease, carotid plaques, hypertension, on antihypertensive therapy, with active rheumatological disorders, alcohol abuse, or malignancy. Notably, prior studies show minimal cIMT differences between the left and right carotid arteries in young adults without atherosclerotic risk factors.^3,4 We chose the CCA over the internal carotid artery, because previous studies indicate that cIMT measured in the CCA holds greater prognostic value for people with T1DM.⁵ Additionally, the vascular age (VA) calculator used in our study (https://www.quipu.eu/vascular‑age‑calculator) is based primarily on right or left (if available) CCA measurements in healthy individuals.⁶

To clarify the imaging process, longitudinal projection images were recorded at 16 frames per second for 5 seconds in an AVI format. We measured cIMT 1 cm proximally to the carotid bulb using the Carotid Analyzer for Research (CAD 5) software (Medical Imaging Applications LLC, Coralville, Iowa, United States) which automatically averaged 100 continuous measurements with a precision of 0.01 mm. This approach avoids manual, single‑point assessments of randomly selected still images, as suggested in Dr. Saleh’s letter. The CAD 5 software is approved by the Food and Drug Administration (510(k) No. K033266) and enhances the consistency and reproducibility of measurements, regardless of electrocardiography gating. More information is available at https://www.mia‑llc.com.

We acknowledge that our methodology differs from some of the cIMT measurement protocols discussed in Dr. Saleh’s previous letters to the editors of other journals (as referenced in PubMed). However, we believe our approach provides robust, reliable results conforming with the aims of our study and the subsequent analyses and conclusions.

Further prospective studies are needed to evaluate the utility of VA and arterial stiffness (AS) as tools for refining cardiovascular risk (CVR) prediction in patients with T1DM. Conventional risk models often underestimate CVR, particularly in younger adults or normotensive individuals. By integrating VA (even from the right‑side cIMT) and AS (via pulse wave velocity) into existing risk models, we may improve their predictive accuracy. We also believe it is important to inform researchers about the advantages of using highly automated cIMT measurements in clinical studies.