# Unilateral Condylar Hyperplasia in Surgeons' Perspective--A Narrative Review
## 5 Imaging Tests for Diagnosis
### Scintigraphy and Growth Activity  
When the first symptoms of asymmetry start to occur, detailed diagnostics should be used. Bone activity is measured in scintigraphy and/or single-photon emission computed tomography (SPECT studies), especially with the use of 99 mTc-MDP because it enables the estimation of the accumulation of calcium components and bone hydroxyapatite [6; 7]. Nuclear studies determine if the growth is still present (active bone growth,--AG+) or if the growth is not present or has ceased growing (growth lack and/or cessation,--GC--) (Figure 5). The difference in uptake levels might vary in each condyle and also be related to patients' age, UCH growth, and even the occurrence of other factors, such as inflammations, tumors/pseudotumors, or surgery in close proximity to the condyle, which might lead to study inaccuracy. Some authors, such as [PERSON] et al. and [PERSON] et al., suggest that differences of 10% in radionuclide uptake between both mandibular condyle heads indicate a bone pathology and signs of UCH [48; 49]. Most importantly, at least two growth measurements should be taken before any other approach within a time frame of 6-12 months to estimate any changes in bone activity. The values of sensitivity and specificity vary greatly. [PERSON] et al.'s study on SPECT accuracy in UCH in 249 retrospective cases indicated that the sensitivity of SPECT was 55.3% and the specificity was 48.6%, which is not very good [35]. These results underline that SPECT has major limitations and should not be used alone without any CT/CBCT/RTG, since 3D anatomical and morphological studies in MC and patients' facial appearances are also very important [12; 13; 20; 50; 51]. Therefore, SPECT in UCH examinations has its limitations and should never be used alone as the  
Figure 4: LDCT coronal view on the condyle head. Notable bone osteogenesis and right condyle head enlargement with ramus elongation are present.  
main indicator for surgery, so additional diagnostics are mandatory. As suggested in the literature, a very advisable approach of \"watch and wait\" is reasonable enough for the estimation and prediction of this type of atypical and unpredictable bone disease, which UCH clearly is [31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 50; 51; 52].  
[PERSON] et al.'s study established that bone scintigraphy and SPECT are important in condylar hyperplasia evaluation and diagnostics [53]. They are also burdened with a high amount of false positive results, especially in trauma cases or in the overloading of the joint, as mentioned by [PERSON] et al. [51]. Since this pathology is mostly case-related, it is worth noting that several situations might be present (Table 1): (1) typical hemimandibular hyperplasia/unilateral condylar hyperplasia case with active/rapid pathological growth starting from childhood or young maturing adults; (2) a form which is self-limiting and ceases growth cessation over time (resulting in visible mandibular and facial asymmetry); (3) a case of slowly progressive growth over time with no limitation of age; (4) condyle head cases of rare benign/malignant tumors (described by [PERSON] et al.); (5) normal growth in the affected condyle, with the contralateral condyle hypoplastic with a lack of inappropriate growth; (6) other related condyle pathologies [30; 54; 55; 56; 57; 58]. It seems that CT imaging is not only superior to a classical RTG, but it also has more value in surgical planning, while SPECT is helpful in the estimation of the presence of any pathological growth component affecting the condyle.  
Figure 5: SPECT evaluation of left side UCH. Presence of enlarged left condylar head with osteosarcoma, typical decrease in glenoid fossa space, and enlarged left ramus of the mandible. Abbreviations: L—left, R—right, H—head/up; F—foot/down, A—anterior, P—posterior.