In addition, FDG-PET demonstrated a strong correlation with the inflammatory markers [38]. For TAK diagnosis (not necessarily active disease), sensitivity of 95% and specificity of 100% were demonstrated to be higher with CTA [39,40]. Noncerebral Vasculitis A prospective study showed that almost 49% of patients had persistent wall thickening despite demonstrating a complete clinical response to treatment. Therefore, the role of CTA in disease monitoring and response to treatment of LVV remains unclear [39]. CTA Coronary Arteries Coronary CTA is an ideal imaging modality for detecting coronary involvement in LVV, particularly in patients with TAK [41]. Kang et al [41] reported that 53.2% of patients with TAK had coronary arterial lesions on coronary CTA, regardless of disease activity or symptoms. Of these patients, 28% had coronary ostial stenosis, 36.9% had nonostial coronary arterial stenosis, and 8.1% had coronary artery aneurysm. The sensitivity and specificity of the FDG-PET/CT to diagnose LVV is considerably high, ranging from 75% to 90% and from 81% to 98%, respectively, when the American College of Rheumatology criteria are used as a reference standard [42,46,49,50]. As mentioned above, the American College of Rheumatology criteria depend on temporal artery biopsy to detect c-GCA. However, in an extensive study, Luqmani et al [51] demonstrated that temporal artery biopsy has a false-negative rate as high as 61%. Therefore, the specificity of FDG-PET/CT in some studies was likely artificially lowered, considering temporal artery biopsy was falsely negative in extracranial GCA [52]. In their study, Lariviere et al [35] demonstrated that both FDG-PET/CT and CTA have a strong diagnostic yield to diagnose LVV; however, FDG-PET/CT appears to have higher PPV (100%) than CTA (84.6%). Similarly, another study found comparable sensitivity and specificity for FDG-PET/CT and CTA for the diagnosis of LVV [36].
Noncerebral Vasculitis. In addition, FDG-PET demonstrated a strong correlation with the inflammatory markers [38]. For TAK diagnosis (not necessarily active disease), sensitivity of 95% and specificity of 100% were demonstrated to be higher with CTA [39,40]. Noncerebral Vasculitis A prospective study showed that almost 49% of patients had persistent wall thickening despite demonstrating a complete clinical response to treatment. Therefore, the role of CTA in disease monitoring and response to treatment of LVV remains unclear [39]. CTA Coronary Arteries Coronary CTA is an ideal imaging modality for detecting coronary involvement in LVV, particularly in patients with TAK [41]. Kang et al [41] reported that 53.2% of patients with TAK had coronary arterial lesions on coronary CTA, regardless of disease activity or symptoms. Of these patients, 28% had coronary ostial stenosis, 36.9% had nonostial coronary arterial stenosis, and 8.1% had coronary artery aneurysm. The sensitivity and specificity of the FDG-PET/CT to diagnose LVV is considerably high, ranging from 75% to 90% and from 81% to 98%, respectively, when the American College of Rheumatology criteria are used as a reference standard [42,46,49,50]. As mentioned above, the American College of Rheumatology criteria depend on temporal artery biopsy to detect c-GCA. However, in an extensive study, Luqmani et al [51] demonstrated that temporal artery biopsy has a false-negative rate as high as 61%. Therefore, the specificity of FDG-PET/CT in some studies was likely artificially lowered, considering temporal artery biopsy was falsely negative in extracranial GCA [52]. In their study, Lariviere et al [35] demonstrated that both FDG-PET/CT and CTA have a strong diagnostic yield to diagnose LVV; however, FDG-PET/CT appears to have higher PPV (100%) than CTA (84.6%). Similarly, another study found comparable sensitivity and specificity for FDG-PET/CT and CTA for the diagnosis of LVV [36].