There are multiple definitions:

1. cardiothoracic ratio(English)

   • heart size measured in relation to the total thoracic width. In patients with HFpEF, increased CTR reflected hemodynamic compromise, along with enlargement of the left atrium and right-sided chambers without LV cavity dilatation. Also denoted as CTI. Not useful in patients with non-ischemic cardiomyopathy
   • CTI, HW/TL, CMR, NICM, LA, RV, HFpEF
   • Cardiology, Radiology, Ratio-based metric
   • https://www.rad…t_anatomy_page8
   • https://doi.org…iol.2024.01.011
   • https://doi.org…jcc.2025.09.008

2. capsular tension ring(English)

   • implantation can benefit cataract patients with weak zonules by maintaining the shape of the capsular bag, reducing capsule shrinkage and stabilizing IOL inclination
   • IOL, PPV, UDVA, BCDVA, AL, CBDm
   • Ophthalmology, Surgery
   • https://doi.org…886-020-01772-8
   • https://doi.org…3350(99)00204-7

3. crest time ratio(English)

   • CT, MSE, MSELS
   • Hemodynamics, Diabetes, Ratio-based metric
   • https://doi.org…1517-014-1220-4

4. carpal tunnel release(English)

   • CTS, BCTQ
   • Musculoskeletal system
   • https://doi.org…54.2022.2100783