Beyond the standard length and angle tools, the viewer includes specialist measurements used in orthopaedics, spine, cardiothoracic and paediatric imaging. This article covers the most common ones.
Cobb angle
Cobb measures scoliosis curvature. Click the upper endplate of the superior vertebra, then the lower endplate of the inferior vertebra. The viewer calculates the angle between perpendiculars.
CTR (Cardiothoracic ratio)
CTR is used on PA chest radiographs. Draw a horizontal midline, then the maximum transverse cardiac diameter and the maximum thoracic diameter. CTR is expressed as a ratio; normal adult is under 0.5.
TT-TG distance
TT-TG Distance measures the offset of the tibial tubercle from the trochlear groove on axial knee imaging. Used in patellofemoral instability workups. Place markers at TG and TT; the viewer calculates the perpendicular distance.
HTO angles and Vertebra Angle
HTO angles (high tibial osteotomy) are used for preop planning. Vertebra Angle measures kyphosis or lordosis between vertebral bodies. Both follow the same three-click angle pattern.
Goniometry and Flatfoot
Goniometry is a multi-joint angle measurement for orthopaedic workups. Flatfoot measures the calcaneal inclination and talar-first metatarsal angle on a lateral foot XR.
Myocardium ROI and Time-Intensity Curve
Myocardium ROI segments the myocardium for perfusion or function studies. Time-Intensity Curve plots signal intensity over time across a series of frames, used in dynamic contrast MR.
Tips
- Not all specialist measurements are available in every deployment. If a tool is missing from your toolbar, it may be licence-gated; contact your AlemHealth account manager.
- When in doubt about which tool to use, choose the simpler general tool. A Cobb measured with the line-and-angle tool is still valid; the dedicated tool just saves clicks.
Related articles
- Basic measurements: length, angle, ROI, area and volume
- Spine labeling
- Calibration