Diaphragm height varies with arm position: comparison between angiography and CT

Area of Science:

• Radiology
• Medical Imaging
• Anatomy

Background:

• Diaphragm height is a critical parameter in radiological assessments.
• Patient positioning can influence anatomical measurements.
• Understanding variations in diaphragm height is important for accurate diagnosis.

Purpose of the Study:

• To investigate the effect of arm elevation on diaphragm height.
• To compare diaphragm height measurements between computed tomography (CT) and angiography.
• To assess the impact of imaging modality on diaphragm position.

Main Methods:

• Retrospective review of 44 patient datasets (CT portography and angiography).
• Diaphragm height measured by two radiologists from the first lumbar vertebra to the highest point of the right diaphragm.
• Paired t-test used for comparison; phantom model evaluated table height and source-image distance (SID) influence.

Main Results:

• Diaphragm height was significantly higher on CT (113.2 ± 27.2 mm) versus angiography (105.5 ± 27.8 mm; P < 0.001).
• Excellent inter-rater correlation for both modalities (R = 0.920 for angiography, R = 0.950 for CT).
• Table height and SID did not influence diaphragm height measurements (P = 0.33).

Conclusions:

• Arm elevation during CT leads to observed diaphragm elevation compared to angiography.
• Imaging technique and patient positioning are crucial factors in diaphragm height assessment.
• These findings have implications for standardized radiological measurements.