This prospective study was conducted between September 2020 and March 2025. Patients were eligible if they met all the following criteria: (1) confirmed diagnosis of Turner syndrome (TS) by karyotype analysis; (2) physical and cognitive ability to complete cardiac magnetic resonance imaging (CMR) without the need for general anesthesia; and (3) written informed consent provided by both the patient and their legal guardian. Exclusion criteria included any contraindications to CMR and failure to provide consent.

Fifty patients were initially recruited from three specialized medical centers in southeastern Poland that provide multidisciplinary care for TS. Of these, one patient declined contrast administration, two were temporarily excluded due to dental braces, three did not appear for scheduled imaging, and one was receiving cardiologic care at another center. Ultimately, 43 patients completed the study protocol and were included in the final analysis.

All patients were admitted with a parent or legal guardian and underwent standardized clinical evaluation, including interview, physical examination, and anthropometric measurements. To ensure confidentiality, all data were anonymized by one of the investigators (MW or EB) immediately following collection.

Karyotype analysis was performed by classic cytogenetic evaluation using 30 peripheral blood lymphocytes.

Height was measured using a Harpenden stadiometer with an accuracy of 0.1 cm, and weight was assessed using a Seca scale accurate to 100 g. Body mass index (BMI) was calculated as weight in kilograms divided by height in meters squared (kg/m²). BMI was classified using Polish reference percentile charts for girls (18), with overweight defined as BMI between the 90th and 97th percentile and obesity defined as BMI above the 97th percentile (Institute of Mother and Child, Warsaw). BMI Z-scores were also calculated using age- and sex-specific standards following the International Obesity Task Force (IOTF) criteria (19).

Height standard deviation scores (hSDS) were determined using the formula:

hSDS = (measured height – height at 50th percentile) / 0.5 × (height at 50th percentile – height at 3rd percentile)

Pubertal development was assessed according to Tanner staging.

The aortic height index (AHI) was calculated as the ascending aortic diameter (in cm) divided by patient height (in meters), while the aortic size index (ASI) was calculated as the diameter (in cm) divided by body surface area (BSA), using the Haycock formula (20) for BSA estimation.

Turner syndrome–specific Z-scores were calculated using the Quezada reference tool for TS (21), and general pediatric/young adult Z-scores were calculated using the Campens reference for healthy populations (22).

Aortic dilatation was defined as any of the following: •

AHI > 20 mm/m

All MRIs were performed using a 1.5T scanner (SIGNA™ Artist, GE Healthcare) at the Saint John Paul II Upper Silesian Child Health Centre. Exams were supervised and interpreted by a single senior radiologist experienced in pediatric congenital heart defects (ZO). All patients received contrast (gadobutrol or gadoteric acid) at a dose of 0.1–0.2 ml/kg. Electrocardiography (ECG) gating was used, and the imaging protocol included Fast Imaging Employing Steady-State Acquisition (FIESTA), Time-Resolved Imaging of Contrast Kinetics (TRICKS), two-dimensional and four-dimensional flow imaging (2D/4D Flow), and three-dimensional heart imaging (3D Heart), covering the thoracic aorta from above the arch to below the diaphragm.

Informed consent was obtained from all participants' legal guardians and patients aged ≥16. The study adhered to ethical guidelines for routine diagnostic care; the formal review was waived (Bioethical Committee of the Medical University of Silesia; PCN/CBN/0022/KB/125/21).

All statistical analyses were conducted using STATISTICA 13.3 (StatSoft). Comparisons between BAV and non-BAV groups were made for ascending aortic diameter, AHI, ASI, and TS-specific Z-score using Welch's t-test for independent samples, which accounts for unequal variances.

Effect sizes were calculated using Cohen's d, with 0.2, 0.5, and 0.8 considered small, medium, and large effects, respectively. The chi-square test was used to assess the association between congenital heart defects and karyotype (45,X vs. non-45,X).

A p-value < 0.05 was considered statistically significant.

Prior to CMR, BAV had been documented in 6 (14.0%) patients and CoA in 1 (2.3%) patient.

CMR newly identified BAV in 9 additional patients, raising the total prevalence to 15 (34.9%), with 60% of cases undetected by previous ECHO. The overall prevalence of anomalies identified by CMR, along with the cases detected before CMR, is shown in Table 2.

Aortic dilatation was observed in 5 patients (11.6%), all of whom had BAV. Clinical characteristics of these patients, including karyotype, height, BMI, and associated cardiovascular defects, are presented in Table 3.

Patients with BAV demonstrated significantly greater ascending aortic diameters, higher AHI values, and elevated TS-specific Z-scores compared to those without BAV (p < 0.05). ASI and general Z-scores showed trends toward significance. No significant associations were found between aortic measurements and the presence of AH or obesity (p > 0.05). Full comparisons are provided in Table 4.

Among the 13 patients (30.2%) who experienced spontaneous menarche and were considered potentially eligible for fertility preservation, 2 (15.4%) had BAV, and 1 had aortic dilatation. Arterial hypertension was present in 3 of these 13 patients (23.0%).

No significant association was found between congenital heart defects and the 45,X karyotype vs. other karyotypic variants (p = 0.063).

Our findings underscore the significant diagnostic value of CMR in adolescents with Turner syndrome, particularly in detecting bicuspid aortic valve BAV. In our cohort, 60% of BAV cases were newly diagnosed by CMR, having previously gone undetected by ECHO. Moreover, all patients with aortic dilatation had BAV, and this group demonstrated significantly greater ascending aortic diameters than those without BAV. Aortic dilatation was newly recognized in four cases; however, it is noteworthy that the ECHOs had been performed considerably earlier in clinical course in three patients. The growth in aortic dimensions is likely associated with age progression (23). This is particularly important given that both BAV and aortic dilatation are key risk factors for AoD, a life-threatening complication in TS. In our cohort, 67% of participants were receiving HRT. Beyond its endocrine functions, estrogen plays a crucial role in vascular biology and connective tissue regulation. It influences collagen synthesis and degradation, modulates elastin content, and affects the expression of matrix metalloproteinases (MMPs)—all of which are essential in maintaining aortic wall integrity and elasticity (24). Although our study did not include a formal subgroup analysis based on HRT exposure, the pathophysiological relevance warrants further exploration in future research. Furthermore, our study identified cases of PAPVR and previously unrecognized great vessel anomalies. Although certain great vessel anomalies may not have immediate clinical significance, PAPVR is associated with right heart volume overload and an elevated risk of developing pulmonary hypertension. Notably, PAPVR frequently remains clinically silent and can be challenging to detect using conventional echocardiography, particularly in individuals with complex thoracic anatomy, such as those with TS (25). In our population, CoA occurs less frequently (2.3%) compared to the rates reported in the literature (4%–15 %10). This discrepancy may be explained by the high proportion of individuals with non-45,X karyotypes in our cohort, given that the presence of a 45,X karyotype is a known risk factor for CoA (26).

The relevance of these findings is further heightened by recent advancements in fertility preservation techniques. Increasing interest in fertility preservation and pregnancy among women with TS necessitates rigorous cardiovascular risk stratification. Guidelines now recommend advanced imaging, such as CMR or CT, within two years before attempting conception or assisted reproductive technologies, due to the high risk of aortic dissection during pregnancy (10). et al. have shown that even borderline aortic dimensions can evolve rapidly under the hemodynamic stress of pregnancy, underscoring the need for early detection and tailored reproductive counseling (27). In this context, incorporating CMR into pre-conception care enables a more accurate assessment of aortic morphology and flow dynamics, particularly in patients with BAV or aortic dilatation, allowing clinicians to better assess contraindications for pregnancy and guide safe reproductive decisions. Importantly, when fertility preservation methods such as ovarian tissue cryopreservation are considered in younger TS patients, CMR should be performed—even under general anesthesia if needed—to avoid invasive procedures in patients with cardiological contraindications to pregnancy.

According to Gravholt et al., aortic dilatation in TS patients is categorized based on age-specific criteria. In children with TS under 15 years, the TS-specific Z-score is the preferred method for evaluation. For individuals aged 15 years and older, the assessment may involve the AHI, ASI, the TS-specific Z-score, or the general population Z-score. Aortic dilatation is characterized by an aortic height index exceeding 20 mm/m, an aortic size index over 2.0 cm/m², or a Z-score greater than 2.5. Severe aortic dilatation occurs when the aortic height index exceeds 25 mm/m, the aortic size index surpasses 2.5 cm/m², or the Z-score is above 4. A rapid increase in the aortic diameter, defined as more than 3 mm per year indicates significant risk (10). These criteria underscore the importance of consistent and accurate monitoring of aortic dimensions using standardized protocols to ensure early detection and timely intervention, reducing the risk of complications associated with aortic dilatation.

Each of our patients has undergone at least one ECHO in their lifetime, often consulting different cardiologists at various medical centers. This highlights the importance of referring patients to cardiologists experienced in TS. When such specialists are unavailable, referrals should include detailed instructions specifying which defects need to be ruled out and which measurements, such as diameters, should be precisely documented. The transition from pediatric to adult healthcare is a critical juncture for ensuring continuity of care. Structured transition protocols should include standardized guidelines for cardiovascular monitoring, patient education on the importance of follow-up imaging, and coordination between pediatric and adult specialists. This approach can reduce the risk of undiagnosed or unmanaged heart defects during adulthood and provide a framework for long-term management.

Although CMR remains the gold standard for imaging the diameter of the ascending aorta, access to it can be limited due to its high cost and the lack of radiologists skilled in cardiovascular imaging. To address this, it is crucial to promote multicenter collaboration and ensure that patients are referred to medical centers with expertise in performing these specialized tests routinely.

ECHO, being non-invasive and readily accessible, is an effective tool for monitoring aortic diameter enlargement over time, particularly as rapid increases in diameter are key predictors of AoD (27). However, CMR provides more detailed insights, especially regarding altered hemodynamics in the aorta, which are direct contributors to AoD. With advanced protocols like 4D flow imaging and fluid-structure interaction algorithms, CMR enables a more comprehensive evaluation of blood flow dynamics and aortic structural changes (28). Figure 1 shows BAV in a patient with TS as visualized on CMR. Figure 2 presents abnormal aortic flow in a patient with a BAV, assessed using 4D flow CMR.

While CMR is the preferred modality for comprehensive cardiovascular evaluation in TS, computed tomography (CT) may serve as a valuable alternative in selected cases. CT offers faster acquisition times, is less affected by patient movement, and can reduce the need for sedation—an important consideration in younger or less cooperative patients. CT also tends to be more widely available and less resource-intensive than CMR. However, the use of CT in this population must be approached with caution due to exposure to ionizing radiation, which is particularly concerning in young female patients, especially those who are or may become pregnant. This risk is amplified in ECG-gated CT protocols, which are used for precise imaging of the aortic root and ascending aorta and typically involve significantly higher radiation doses. Thus, the decision to use CT must be carefully individualized, balancing diagnostic utility against potential radiation risks (29).

It is important to note a potential selection bias in our cohort. All participants were able to undergo CMR without anesthesia, which may reflect a subset of TS individuals who are more physically and cognitively able. Consequently, those with severe developmental, behavioral, or medical challenges may have been underrepresented, which limits the generalizability of our findings to the broader TS population. In clinical settings where CMR is not feasible, CT may still offer diagnostic value, though decisions should be made within the context of individual capabilities, risk profiles, and available expertise.

Another major limitation of this study is the small sample size, which is a result of TS being a rare disease. This rarity leads to recruitment difficulties, inherent variability among patients, and the necessity for multicenter collaborations. Another challenge was the reliance on inconsistent results from ECHO performed by different specialists. However, this inconsistency provided valuable insight into the current state of cardiological care for TS patients, highlighting the need for improvements in this area.