Basal ganglia calcification (BGC) is a common incidental finding on brain computed tomography (CT) imaging, with reported prevalence ranging from 0.3% to 1.5% in the general population^4,8). While often considered a benign age-related change, BGC may serve as an important radiological marker indicating systemic predisposition to pathological calcification processes^13,14). The presence of BGC has been associated with various metabolic disorders, including hypoparathyroidism and pseudohypoparathyroidism, suggesting its potential role as a surrogate marker for generalized calcification tendencies^13,14).

Recent studies have demonstrated that BGC is associated with both local and systemic metabolic mechanisms, particularly involving calcium-phosphate homeostasis and inflammatory pathways^13,14). The histological analysis of incidental BGC has revealed complex calcification patterns that may reflect broader systemic disorders affecting mineral metabolism³⁾. These findings raise the hypothesis that BGC could reflect a systemic predisposition to calcification, though causal relationships cannot be established in this study.

Ossification of the posterior longitudinal ligament (OPLL) and diffuse idiopathic skeletal hyperostosis (DISH) are progressive spinal disorders characterized by ectopic ossification and calcification of spinal ligaments. OPLL predominantly affects the cervical spine, involving pathological OPLL, potentially leading to spinal cord compression and myelopathy^1,11,12,15). DISH is a systemic skeletal disorder characterized by calcification and ossification of spinal ligaments, particularly the anterior longitudinal ligament, along with peripheral enthesopathy^5,10). Both conditions demonstrate irreversible progression once established, making early detection and intervention crucial for optimal patient outcomes^1,11).

The pathophysiology underlying both OPLL and DISH involves complex genetic and inflammatory mechanisms that promote ectopic ossification^2,6,7). Recent studies have identified genetic contributions to spinal ligament ossification, with evidence suggesting shared pathways between different ossification disorders^2,7). Furthermore, inflammatory markers such as interleukin-17 (IL-17) have been associated with ectopic bone formation in OPLL patients with concurrent DISH⁶⁾. The prevalence and distribution of these conditions vary significantly across populations, with higher rates observed in Asian populations^5,10).

Despite sharing common pathological mechanisms involving aberrant calcium metabolism and inflammatory processes, the potential association between BGC and cervical spine ossification disorders has received limited attention in the literature. Previous studies have primarily focused on these conditions in isolation, overlooking their possible interconnection as manifestations of a systemic calcification phenotype⁹⁾. Given the widespread use of brain CT imaging in clinical practice and the potential for early detection of cervical spine pathology, investigating this relationship could have significant clinical implications.

If a significant association exists between BGC and cervical spine ossification disorders, the presence of BGC on routine brain imaging might serve as a valuable screening tool, prompting further cervical spine evaluation in at-risk patients before the onset of neurological symptoms. This approach could facilitate early diagnosis and intervention, potentially improving patient outcomes and reducing the burden of advanced cervical spine pathology.

Therefore, this study aimed to investigate the association between BGC and cervical spine ossification disorders, specifically OPLL and DISH, using a large-scale retrospective imaging analysis. We hypothesized that patients with BGC would demonstrate significantly higher prevalence of cervical OPLL and DISH compared to those without BGC, supporting the concept of BGC as a potential systemic marker for spinal ossification disorders.

This retrospective cross-sectional study was conducted at Chungbuk National University Hospital and approved by the Institutional Review Board (IRB approval no. 2025-07-009). Patients who underwent non-contrast brain CT between March 1, 2023, and February 28, 2025, were initially screened. Among these, patients who also underwent cervical spine CT or neck CT within the preceding five years were included in the study cohort.

Inclusion criteria were: (1) age ≥ 18 years; (2) availability of both brain CT and cervical spine/neck CT within the specified time window.

Exclusion criteria were as follows: (1) suboptimal image quality preventing accurate evaluation of calcifications or ossifications (e.g., severe motion artifact or beam hardening); (2) age under 18 years; (3) known congenital or systemic bone diseases (e.g., Paget's disease, osteogenesis imperfecta, or hypophosphatemia); (4) history of cervical spine surgery; (5) severe trauma affecting cervical anatomy.

After applying the inclusion and exclusion criteria, a total of 1,911 patients were included in the final analysis.

This study represents the first large-scale imaging-based analysis demonstrating a clear association between BGC and cervical spine ossification disorders. Our findings reveal that patients with incidental BGC have significantly higher risks of developing both OPLL (adjusted OR, 4.41) and DISH (adjusted OR, 2.79), representing robust and clinically meaningful associations that persist even after adjusting for age and sex.

The observed BGC prevalence of 15.7% in our cohort is consistent with recent large-scale studies, which report prevalence rates ranging from 8% to 20% depending on the population studied and imaging criteria used^4,8). Our findings of 13.6% OPLL prevalence and 8.4% DISH prevalence in the Korean population align with previous Asian studies, which consistently show higher rates compared to Western populations^5,10). The strong associations demonstrated in our study (Fig. 1) raise the hypothesis that BGC may reflect a systemic predisposition for systemic calcification or ossification tendencies, supporting recent research demonstrating that BGC reflects broader metabolic disturbances affecting calcium-phosphate homeostasis^13,14).

The particularly strong association observed with OPLL (OR, 4.41) compared to DISH (OR, 2.79) may reflect different underlying pathophysiological mechanisms. OPLL primarily involves ossification of ligamentous structures via endochondral ossification pathways, while DISH represents a more generalized skeletal hyperostosis affecting multiple anatomical sites^2,7). Recent genetic studies have identified shared susceptibility loci between different ossification disorders, suggesting common molecular pathways involving bone morphogenetic proteins, transforming growth factor-β, and Wnt signaling cascades^2,7).

The inflammatory component appears crucial in linking BGC to spinal ossification disorders. Elevated levels of inflammatory markers, particularly IL-17, have been documented in patients with concurrent OPLL and DISH⁶⁾. These inflammatory cytokines may be involved in shared pathways contributing to ectopic calcification and spinal ossification through similar molecular mechanisms involving osteoblast differentiation and matrix mineralization^6,9).

Furthermore, metabolic factors play a significant role in both conditions. Studies have shown that BGC is associated with disturbed calcium-phosphate metabolism, often involving parathyroid hormone dysfunction and vitamin D abnormalities^13,14). These same metabolic disturbances have been implicated in the pathogenesis of spinal ossification disorders, suggesting a common underlying susceptibility to ectopic mineralization processes.

The clinical implications of our findings are significant and multifaceted. Given the widespread use of brain CT imaging in emergency departments, outpatient clinics, and routine health screenings, the presence of incidental BGC may be explored as a potential clinical indicator in future prospective research for identifying patients at risk for cervical spine ossification disorders. This is particularly relevant because both OPLL and DISH can remain asymptomatic for years before presenting with neurological complications^1,11).

Our results suggest that patients with incidental BGC, particularly elderly males, may benefit from cervical spine CT evaluation even in the absence of cervical symptoms. This approach could facilitate early diagnosis and intervention, potentially preventing the development of cervical myelopathy and improving long-term outcomes. The cost-effectiveness of such a screening approach would need to be evaluated, but the high ORs observed in our study suggest that the yield would be substantial.

However, the use of cervical CT as a screening modality in asymptomatic individuals raises concerns due to radiation exposure, cost, and limited clinical utility in detecting small, subclinical lesions. Cervical radiographs, being more accessible and involving lower radiation, may serve as a more practical alternative for initial screening in patients with incidental BGC. Future studies comparing the diagnostic performance and feasibility of radiography versus CT in this context are warranted.

While our regression model adjusted for age and sex, other important metabolic factors—such as diabetes mellitus, chronic kidney disease, parathyroid hormone abnormalities, and disruptions in calcium-phosphorus metabolism—were not included in the analysis due to the retrospective nature of our dataset. These conditions are known to influence both vascular and ectopic calcification processes and may act as confounding variables. Therefore, the observed associations between BGC and cervical spine ossification disorders should be interpreted with caution. Future studies incorporating detailed metabolic profiles are warranted to clarify the independent nature of this relationship.

Early detection is crucial because both OPLL and DISH demonstrate irreversible progression once established^1,11). Patients diagnosed with early-stage disease could benefit from lifestyle modifications, regular monitoring, and prophylactic measures to prevent trauma-related spinal cord injury. Additionally, knowledge of these conditions is essential for anesthesiologists and surgeons performing procedures involving cervical spine manipulation.

Future research should investigate whether the degree or pattern of BGC correlates with the severity or anatomical extent of cervical ossification. Additionally, similar studies in prospectively designed cohorts with comprehensive control of metabolic factors—including parathyroid function, calcium-phosphorus balance, and vitamin D status—are needed to clarify the nature of the observed associations and explore potential causative links.

Several limitations should be acknowledged. First, this is a single-center retrospective study, which may limit the generalizability of our findings. Second, the cross-sectional study design precludes establishing causal relationships between BGC and cervical spine ossification disorders. Third, we did not evaluate other potential confounding factors, such as metabolic disorders, inflammatory markers, or genetic factors, which might influence both BGC and spinal ossification. Future prospective studies with larger multicenter populations and comprehensive metabolic evaluations are needed to confirm these findings.

Incidental BGC is associated with a significantly increased risk of cervical OPLL and DISH. Brain CT scans revealing BGC may prompt consideration of cervical spine evaluation, especially in elderly male patients. These findings raise the possibility that BGC could be explored as a potential indicator in future screening strategies, though prospective validation is required before clinical application.