Synthetic Hematocrit

Please input the T1 blood value to calculate synthetic hematocrit for your case. All math runs in your browser; nothing is uploaded.

Calculator

Synthetic hematocrit —

Formula

This page uses the following formula. Reference: Triebel TA et al JACC: Imaging 2016.

Synthetic hematocrit = (866 × [1 / T1blood]) − 0.1232

T1blood in milliseconds. Worked example: ROI native T1 blood 1566 ms → Synthetic-Hct ≈ 0.429 (vs measured 0.425). Spreadsheet check: 1543 → ≈ 0.438 (43.8%).

CVi42 steps

How to calculate synthetic hematocrit for ECV calculation in CVi42.

  1. Enter the T1 calculation section in CVI42 (select the T1 mapping tool).
    CVi42 toolbar: T2*, T1 (highlighted with red callout), and T2 mapping icons.
    T1 tool in the CVi42 mapping toolbar.
  2. Drag one of the T1 mapping sequences to the window.
  3. Use the ROI tool to draw a blood-pool ROI as below. Be sure to exclude papillary muscles.
    CVi42 T1 Calculation Results: ROI 1 native T1 1566 ± 603 ms, R² = 0.997, with short-axis MRI showing pink blood-pool ROI.
    Example: ROI 1 native T1 blood 1566 ms (pink blood-pool ROI on short-axis slice).
  4. Enter the calculated T1 value into the formula above (or the calculator on this page).
  5. Use the resulting synthetic hematocrit for ECV if a measured hematocrit is unavailable. Worked example from the SOP: native T1 blood 1566 ms → Synthetic-Hct ≈ 0.429 (this patient’s measured hematocrit was 0.425).

ECV

Optional second section. Extracellular volume from native and post-contrast T1 of myocardium and blood, scaled by (1 − hematocrit).

ECV calculator

Hematocrit source

Hematocrit used —
ECV —

ECV formula

ECV = (1 − Hct) × [ ((1/T1myo,post) − (1/T1myo,native)) / ((1/T1blood,post) − (1/T1blood,native)) ]

Example: native blood 1566, native myo 1018, post blood 346, post myo 481, Hct 0.425 → ECV ≈ 0.280 (28%).

Educational / clinical aid only. Calculations run entirely in your browser; do not paste PHI into screenshots you share. Verify results locally against your site protocol and measured laboratory hematocrit when available. Formula reference: Triebel TA et al JACC: Imaging 2016.

Special thanks to Anushri Parakh, MD.