Related Experiment Video
Updated: Feb 8, 2026
Neutron Radiography and Computed Tomography of Biological Systems at the Oak Ridge National Laboratory's High Flux Isotope Reactor
Published on: May 7, 2021
Correlation of Measurements of the Prearthritic Hip Between Plain Radiography and Computed Tomography
Mary E Air1, Julian R Harrison1, Joseph T Nguyen2
1Department of Physiatry, Hospital for Special Surgery, New York, New York.
Background:
Previous studies have compared radiographic and computed tomography (CT) imaging for the evaluation of prearthritic hip pain. However, the intermodality, interrater, and intrarater consistencies of those parameters have not been investigated.
Objective:
To determine whether radiographs with an anteroposterior pelvis view and 45°-Dunn lateral view reliably correlate with CT in the context of lateral center edge (LCE), Tonnis, alpha, and beta angle measurements for femoroacetabular impingement or hip dysplasia diagnosis.
Design:
Retrospective study.
Setting:
Academic orthopedic institution.
Patients:
Fifty consecutive participants with hip pain in the institutional hip registry with radiographs and CT imaging on file were evaluated between 2013 and 2014.
Materials And Methods:
Radiologic data (50 CTs and 50 radiographs) were evaluated by 3 physicians. LCE, Tonnis, alpha, and beta angles were measured on radiographs and CTs in 2 rounds of readings. In round 1, the center of rotation on CT imaging was standardized by 1 rater. In round 2, individual raters chose CT images using a quadrant method, and reproducibility was assessed. Reliability statistics were operationalized with intraclass correlation coefficients (ICCs).
Main Outcome Measurements:
Intermodality, intrarater, and interrater reliability of CT vs radiographic measurements.
Results:
The intermodality reliability for all raters was excellent (ICC [95% CI]: 0.84 [0.76-0.90] to 0.97 [0.96-0.98]). Intrarater reliability for both modalities showed excellent reliability (ICC = 0.75-0.96). Interrater reliability of CT measures of LCE, Tonnis, and alpha angles demonstrated excellent agreement (ICC ≥ 0.88). Beta angle measures demonstrated good agreement (ICC [95% CI] = 0.68 [0.49-0.81]). Interrater reliability of radiographic measures showed excellent agreement (ICC = 0.82-0.94).
Conclusion:
Equivalent angle measurement readings on CT and radiographs were consistent among physicians. CT measurements correlated well with radiographic measurements. This suggests that if a standardized procedure is used to find the center of the femoral head, a positive correlation among LCE, alpha, beta, and Tonnis angles measured on CT can be obtained between multiple readers.
Level Of Evidence:
III.
More Related Videos
Related Concept Videos
01:10Computed Tomography
The technique was invented in the 1970s and is based on the principle that as X-rays pass through the body, they are absorbed or reflected at different levels. In the technique, a patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates...
01:27Imaging Studies III: Computed Tomography
02:20Correlations
01:27Correlation and Causation
Correlation versus Causation
If the dependent variable increases or decreases when the independent variable increases, there is a positive or negative...
01:09Correlation
Two variables, for example, a and b, are said to be positively correlated if both variables move in the same direction. In other words, a positive correlation exists between two variables, a and b, if:
00:53Correlation and Regression