Cardiothoracic Ratio

Purpose	Measure cardiothoracic ratio on posterioranterior and anteroposterior radiographs
Tag(s)	#Cardiac Size on Chest Radiograph
Panel	Cardiac
Define-AI ID	18040003
Originator	Jay Nance
Panel Chair	Carlo De Cecco
Panel Reviewers	Cardiac Panel
License	Creative Commons 4.0
Status	Published

                               

Value Proposition

The chest radiograph is often the first imaging study that is available. It can be used as a quick initial screening tool for cardiomegaly, which in and of itself can be used as a marker for heart disease. A quick visual assessment by a radiologist is sometimes inaccurate. An AI algorithm can be trained to make an accurate assessment of cardiomegaly based on single-view chest radiograph (anteroposterior [AP] or posterioranterior [PA]). Additionally, the algorithm can indicate which specific chambers contribute most to the enlarged cardiac silhouette.

Narrative(s)

A 60-year-old male with no prior imaging is admitted to the ED for shortness of breath. A chest radiograph is obtained as part of the initial workup. The algorithm evaluates the image and determines whether the patient’s heart is enlarged. The radiologist is informed of this categorization at the time of interpretation. Additionally, the algorithm is able to evaluate for enlargement of the left atrium (or other specific chambers).

Workflow Description

The image obtained from the modality is sent to PACS and the AI engine. The image is analyzed by the engine. If the image is a PA view, a simple cardiothoracic ratio (width of heart/width of thorax) is computed. If the image is an AP view, a “modified” cardiothoracic ratio is computed. The system categorizes the heart as enlarged or normal in size based on whether the cardiothoracic ratio is greater than 0.5. If the heart is enlarged, the angle of the carina is measured by the system. If the angle is greater than 100 degrees, the presence of left atrial enlargement is suggested. A message is sent to PACS from the engine with the information.

Procedures(s): X-ray, Chest

View(s): {AP, PA}

 

Sex at Birth: {Male, Female}

Inputs

DICOM Study

Procedure	XRAY, Chest
Views	AP, PA
Data Type	DICOM
Modality	XRAY
Body Region	Chest
Anatomic Focus	Heart

 

Primary Outputs

Cardiothoracic Ratio

RadElement ID	RDE382
Definition	Cardiac size expressed as cardiothoracic ratio
Data Type	Numeric
Value Set
Units	N/A

If the cardiothoracic ratio is greater than 0.5, then suggest cardiomegaly. If the cardiothoracic ratio is greater than 0.5 and the carina angle is greater than 100 degrees, then suggest atrial enlargement.

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