The assessment of the frequency and arrangement of the subsegmental branches of V3 using computed tomography angiography.

BACKGROUND: The frequency and arrangement of the subsegmental branches of the third portion of the vertebral artery (V3) have been assessed in small samples by autopsy, but they have not been assessed by computed tomography angiography (CTA). To determine the frequency and arrangement of subsegmental branches of V3 by CTA and to analyze the interrelationships among frequency, arrangement, sex, and side-to-side. METHODS: First, the radiology records of 668 consecutive patients who underwent cervical or craniocervical CTA scans from October 1, 2017 to October 31, 2019 were retrospectively retrieved. Second, the four demarcation points were ascertained to define the three subsegments by reviewing the resource images, namely, the vertical portion of V3(V3v), horizontal portion of V3(V3h), and extradural portion of V3(V3e). Then, the numerical value and the location of the bifurcating branch in each subsegment of V3 were recorded. Third, the frequency and arrangement of the branches was assessed, and the relationships between sex, laterality and frequency and arrangement were analyzed as well as the interobserver performance. RESULTS: On the left, 25%, 20.21%, and 6.59% were the frequencies of one branch in the V3v, V3h, and V3e, and 1.05%, 0.00%, and 0.45% were the frequencies of two branches, respectively. On the right, 25.04%, 17.07%, and 6.44% were the frequencies of one branch in the V3v, V3h, and V3e, and 1.04%, 0.3%, and 0.15% were the frequencies of two branches, respectively. There were no differences between the side-to-side and numerical values of the branches according to the t-test (P=0.4341, P=0.7968), and there were no differences between the side-to-side variable, sex variable and number of branches according to the t-test (P=0.4474, P=0.3593). There were no differences between the side-to-side and eight arrangements (permutation of 000; 100; 110; 111; 010; 011; 001; 101) by using the two-sample KS test (P=0.942), and there were no differences between sex and the eight arrangements according to the two-sample KS test (P=0.9973, P=0.8519). The interobserver reliability was excellent (Spearman's ranked correlation: 0.9927). CONCLUSIONS: The frequency and arrangement of V3 subsegmental branches could be displayed by source imaging with CTA, and there were no significant differences according to the sex or side of the individual. It was imperative to acquaint the subsegmental branches before the operation involving V3 in the craniocervical junction to determine the surgical approach and reduce bleeding during the surgical procedures.

The prevalence of osteoarthritis of the atlanto-odontoid joint in adults using multidetector computed tomography.

BACKGROUND: The prevalence of osteoarthritis of the atlanto-odontoid joint has been reported by radiology, autopsy, and conventional computed tomography (CT), but the prevalence has not yet been assessed by multidetector computed tomography (MDCT). PURPOSE: To reveal the prevalence of osteoarthritis of the atlanto-odontoid joint and to analyze the inter-relationships among gender, age, and osteoarthritis with MDCT in adults. MATERIAL AND METHODS: First, a series of 700 selected domestic patients aged >18 years undergoing an upper cervical MDCT scan were divided equally into seven age groups. Second, using the postprocessing technique of multiplanar reconstruction, osteoarthritis of the atlanto-odontoid joint was viewed from any direction and classified into four grades, which were normal, mild, moderate, and severe. Lastly, the incidence of the different grades of osteoarthritis was assessed, and the reproducibility was tested. RESULTS: There was no significant difference between gender and osteoarthritis of atlanto-odontoid joint (P > 0.05). The rate of osteoarthritis was 16% in the age group 18-25 years, 23% in the age group 25-30 years, 33% in the age group 30-40 years, 54% in the age group 40-50 years, 70% in the age group 50-60 years, 87% in the age group 60-70 years, and 93% in the age group >70 years. Mild osteoarthritis appeared at the earliest at age 19.6 years, moderate osteoarthritis in at earliest at age 24.2 years, and severe osteoarthritis at the earliest at age 48.5 years. The inter-observer reliability was excellent (k = 0.86). CONCLUSION: Osteoarthritis of the atlanto-odontoid joint could be detected by MDCT in a young adult. It increased rapidly with increasing age on MDCT.

Normative data on axial rotation of atlanto-occipital joint on 3 Tesla MRI using a simple and reliable method of calculation.

BACKGROUND: Various methods have been used to image and measure the normal range of axial rotation of the atlanto-occipital joint (AOJ), but a simple, precise, and reliable method is needed for everyday practice. PURPOSE: To generate normative ranges for AOJ rotation in various in-vivo positions and to investigate the reliability of a simple imaging method for measurement using routine high-field magnetic resonance imaging (MRI). MATERIAL AND METHODS: One hundred healthy volunteers were imaged on 3 T MRI with the AOJ in the center of the field of view. The scans were uniformly performed in seven different positions. The range of axial rotation was calculated by the angle between the craniofacial midline and the line linking the anterior and posterior tubercles of the atlas. The angle was defined as positive when it was angled right, and negative when it was angled left. The actual normative range of axial rotation was the difference between the angle in the supine neutral position and in the other positions. RESULTS: The normative axial rotation range of the AOJ in different positions was between -4.8° and +5.0°. The mean values of the actual rotation angles in the right supine position with maximum bending, the right supine position maximum rotation, and the right prostrate position maximum rotation were 0.1°, 1.70°, and 0.8°, respectively. The mean values of actual rotation angles in the left supine position with maximum bending, the left supine position with maximum rotation, and the left prostrate positive with maximum rotation were 0.1°, -1.7°, and -1.1°, respectively. The inter-observer reliability tested. CONCLUSION: A simple and reliable method of measurement on 3.0 T MRI demonstrated the normative axial rotation range of the AOJ in different positions to be between -4.8° and +5.0° and it was different from zero in neutral rotation. This method could be practically used to precisely diagnose AOJ rotary subluxation or dislocation.