Left Ventricle T2 Mapping Quantification

Purpose	Quantify T2 relaxation time of the myocardium of the left ventricle.
Tag(s)
Panel	Cardiac
Define-AI ID	19040032
Originator	Benoit Desjardins
Lead	Benoit Desjardins
Panel Chair	Carlo De Cecco
Panel Reviewers	Cardiac Panel
License	Creative Commons 4.0
Status	Public Comment
RadElement Set	RDES141

Value Proposition

Cardiac MRI is a noninvasive tool to assess cardiac morphology, function and characteristics of myocardial tissue. An important tissue characteristic is myocardial edema, often present in acute heart disease, either ischemic and non-ischemic. Disease with increased myocardial T2 values include myocarditis, myocardial infarct, graft rejection, Takotsubo cardiomyopathy, etc. The technique of T2 mapping (T2 transverse relaxation time mapping) builds a parametric image based on the transverse relaxation time of each voxel and offers a quantitative assessment of myocardial edema. An algorithm can automatically measure T2 values from T2 maps and alert the user if these measurements are higher than the normal range.

Narrative(s)

A 30-year-old female presents in the ER with chest pain and elevated troponins. Acute myocarditis is suspected, given her age and lack of prior cardiac disease history. A cardiac MRI is ordered to evaluate function and myocardial edema to help confirm this diagnosis. MRI shows diffusely increased T2 map values in lateral wall, indicating myocardial edema, some decreased function and nonischemic late gadolinium enhancement pattern. Given these findings, acute myocarditis is the most likely diagnosis.

Workflow Description

Pre-contrast T2 mapping is performed at 2 or 3 different short-axis levels in the left ventricle. On the resulting T2 map images, the LV myocardium is segmented. On each T2 map image, ROIs are traced in the septum, anterior wall, lateral wall and inferior wall. The average T2 value is computed for each ROI and displayed. A normal range of T2 values depending on scanner and field strength is also displayed. The algorithm alerts the physician if any of the myocardial walls show values above the normal range.

Procedure(s)	Cardiac MRI
Sex at Birth	{Male, Female}
Age	[15,90]
Weight	[90 lbs, 350 lbs]

Inputs

DICOM Study

Procedure	Cardiac MRI
Views	N/A
Data Type	DICOM
Modality	X-ray
Body Region	Chest
Anatomic Focus	Heart

Primary Outputs

Native T2

RadElement ID	RDE945
Definition	Native average T2 tissue for each ROI
Data Type	Numeric
Value Set	N/A
Units	ms

Secondary Outputs

Presence of myocardial edema

RadElement ID	RDE946
Definition	Alert if ROI shows higher signal than the normal range
Data Type	Categorical
Value Set	Unknown Suspected edma No edema
Units	N/A