Background/Purpose:

The absence of the parietal branch of the temporal artery during an ultrasound evaluation may be due to a variance of the normal anatomy or to technical difficulties due to interference of hair. However, the significance of a complete absence of the frontal branch without any obvious stenosis or sudden occlusion is not known. The objective of the present study was to determine if the non-observation of the frontal branch of the temporal arteries by ultrasonography had any diagnostic value in patients with a clinically suspected GCA, as defined by biopsy or the ACR classification criteria.

Methods:

From May 2011 to February 2017, 102 patients underwent an US evaluation of the temporal arteries for suspected GCA. US of the common, parietal and frontal branches of the TA were done with a MyLab70 device and Color Doppler technique, bilaterally. A definitive stenosis was diagnosed when the frontal branch had its diameter decreased or the blood flow increased by at least twofold; obstruction was diagnosed by the sudden loss of a proximally well-identified artery. Non-observation was defined when at least one of the frontal branches of the temporal arteries was not observed at all.

Results:

102 patients were included in the study: 71.6% of them were women and the average age was of 72 years ; 49% of the patients presented at least 3 ACR criteria for GCA. 18 patients underwent a temporal artery biopsy, 4 with positive results. A definitive stenosis or occlusion on US examination was found in 11 of our patients. In 12 other patients the frontal branch of one of the temporal arteries could not be identified during US examination.

Compared to the ACR criteria, the presence of a definite stenosis had a sensibility of 18,6%, a specificity of 93,6 %, a PPV of 72,7% and a NPV of 55,7%. The non-identification of at least one frontal branch had a very similar predictive value: sensitivity of 14%, specificity of 90,4%, PPV of 58,3% and NPV of 52,2% . Compared to the biopsy, the presence of a definite stenosis or occlusion had a sensitivity of 100%, a specificity of 84,6%, a PPV of 33.3% and a NPV of 100%, while the non-observation of the frontal branch of the TA showed 75%, 85,7%, 60% et 92,3%, respectively.

Conclusion:

In our cohort the non-observation of the frontal branch of the temporal arteries was highly predictive of GCA whether the disease was defined by ACR criteria or by biopsy. Its predictive values were very close to those found for stenosis or occlusion, suggesting that it may be a manifestation of the same phenomenon.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/diagnostic-value-of-the-non-observation-of-the-frontal-branch-of-the-temporal-arteries-by-ultrasonography-in-the-diagnostic-of-giant-cell-arteritis-gca/