DISH is considered as one of the most common etiologies of atypical bony formations (i.e., osteophytes; [8]). Based on Kim and colleagues (2018) [9], the presence of spinal calcifications was most commonly found in the middle part of thoracic spine (90.0%) and the lower part of thoracic spine (87.5%), followed by the cervical spine (43%). Most common symptoms of DISH include back pain, neck and/or back stiffness, and decreased range of spinal motion, but it may also result in more severe complications such as dysphagia, airway obstruction, and hoarseness, and vulnerability to spinal fractures [1]. Quintero-Gonzalez, Arbelaez-Cortez, and Rueda (2019) [10] stated that symptoms of DISH are typically based on the localization of the calcifications with spinal changes (e.g., axial pain, reduced axial range of motion, nerve root symptoms) being the most common manifestations related to the disease.

While the cause and pathogenesis of the disease are still poorly understood, researchers from different parts of the world had attempted to describe the prevalence of DISH in relation to various factors such as age, gender, and presence of metabolic diseases. In Italy, the prevalence of DISH among 1012 individuals was found to be 12.8% with the male participants having a higher preponderance (16.8%) than the female (10.3%). Additionally, the researchers found a significant relationship between DISH and age, BMI, and/or the presence of chronic diseases such as metabolic syndrome (Ciaffi et al, 2022). In another study conducted by Ahmed and colleagues (2022), the researchers found 19.1% of overall prevalence of DISH among 1815 participants, which increased with age. No participants among the 20-29 age group were diagnosed with DISH; the 30–39-year-old group showed the lowest DISH prevalence of 1.1%, while individuals aged 70-79 and older than 80 years old showed highest prevalence of the condition with 45.2% and 45.5% respectively (Ahmed et al, 2022).  A cross-sectional study in Japan also reported similar results, particularly the presence of thoracic DISH after 40 years old and the highest preponderance of DISH in the thoracic vertebrae among the 70 years age group [11]. Therefore, the presence of DISH in the 20-29 and 30-39 age groups are extremely rare.

One of the most frequently adopted diagnostic criteria for DISH described by Resnick and Niwayma in 1976, is calcification and ossification along at least four adjacent vertebral bodies, the relative preservation of disc height accompanied with the lack of evidence for extensive radiographic changes of disc degeneration, and the absence of apophyseal joint bony ankylosis and sacroiliac joint erosion, sclerosis or intra articular bony fusion. The criteria was later modified (Table 1) to improve interobserver agreement for diagnosing DISH based on CT results [12]. The Reznickand Niwayma criteria has recently faced several challenges due to its limitations to more advanced and severe stages of DISH. Considering this, Kruper and colleagues (2019) [13] provided another set of criteria that is more suitable for confirming early-phase DISH, as follows: “a segment with a complete bone bridge with an adjacent segment of at least a near-complete bone bridge AND another adjacent segment with at least the presence of newly formed bone; OR when at least three adjacent segments were recorded as showing a near-complete bone bridge.)”

The most common imaging modality for confirming DISH at present is the use of plain radiography. Meanwhile, CT scan has recently been reported to possess higher sensitivity in detecting DISH and evaluating the structural changes associated with condition, while MRI is more sensitive in capturing the soft tissues of the spine, proving it to be a useful instrument in the differential diagnosis of DISH and Ankylosing Spondylitis (AS) since MRI is capable of detecting inflammation that is typical in AS [5,14,15]. Recently, bone scintigraphy with hybrid images of single photon emission computed tomography- computed tomography (SPECT-CT) has been introduced to provide accurate anatomical and functional imaging and precise localization of the spinal lesion by determining the location with increased radiotracer uptake [5]. To date, various researchers had attempted to explore the utilization of SPECT-CT in different rheumatologic and orthopedic lesions.

Kim and colleagues (2015) [16] studied the usefulness of bone SPECT/CT imaging in early axial spondyloarthritis as compared to conventional imaging techniques such as plain radiography and CT alone. The researchers found more advantages of using SPECT/CT because of its higher sensitivity (80.0%) and specificity (84.6%) in terms of detecting SIS ratio [16]. On the other hand, a report on the applications of SPECT/CT in musculoskeletal radiology also described the advantages of the said imaging technique with other tools (e.g., MRI, CT alone, SPECT alone) in evaluating both malignant and benign diseases in the axial skeleton. SPECT/CT was also beneficial in localizing chronic lower back pain for target-specific pain management by combining functional imaging with SPECT, which cannot be achieved by planar imaging or anatomical imaging alone [17,18]. Therefore, SPECT/CT proves to be a potential tool in achieving an accurate diagnosis for spinal lesions, cervical facet joint arthritis [19], sternoclavicular joint arthritis [20] and meniscus tear of knee joint [21]. Obtaining information on the functional changes before structural calcifications in DISH is important for early detection and intervention of DISH, preventing possible life-threatening complications. However, the impact and significance of SPECT/CT on DISH diagnosis across all age groups have not yet been studied at present.

Assogba and colleagues (2014) [7] described an extremely rare case of early-stage DISH in a 20-year-old male, which was the only study on DISH in the 20-29 years age group to date. Chitten and James (2019) [3] also presented a unique study of DISH, which involved a 33-year-old woman with polycystic ovarian syndrome (PCOS). Both reports merely used plain radiography and/or CT scan and MRI to confirm DISH, while the use of SPECT/CT was not mentioned. Morales, Ornilla, Sancho, and Guillen (2019) published a case that primarily focused on SPECT/CT as the primary diagnostic tool of DISH, but the patient of their study belonged to the 60–69-year-old age group, which was one of the populations with highest DISH prevalence.

Therefore, our case is the first to report an extremely rare case of a patient with DISH, whose symptoms began at 21-22 years old, which was far below the typical age of onset of the disease (i.e., 45-40 years old; the patient is currently 24 years old), and was primarily diagnosed through the use of SPECT-CT. Our study provides an interesting perspective on using SPECT-CT as a potential primary diagnostic tool for early-phrase DISH. Studies from Japan, Taiwan, and Netherlands showed a significantly higher incidence of cerebral infarction with a 55-68% increased rate of ischemic stroke (22-24). We also suggest that the onset of DISH may have started several years before symptoms become apparent and more severe. Hence, further research in exploring SPECT-CT to diagnose early signs of DISH or other spinal pathologies is strongly recommended.