Emission-based attenuation correction of myocardial perfusion studies

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Radiology

Background:

• Nonuniform thoracic attenuation causes artifacts in myocardial perfusion studies, mimicking coronary artery disease.
• Current methods often require transmission measurements, adding complexity and cost.

Purpose of the Study:

• To present and validate an emission-based method for correcting attenuation effects in myocardial perfusion imaging.
• To demonstrate the method's efficacy without requiring transmission scans.

Main Methods:

• An attenuation map was generated using 99mTc-labeled macroaggregated albumin distribution in lungs and a radioactive binder.
• Segmentation defined lung and body compartments with assigned attenuation coefficients.
• The technique was evaluated using phantom, simulation, and clinical data from 20 patients.

Main Results:

• Positron emission tomographic data showed low standard deviations in attenuation coefficients for body (<5%) and lungs (<15%).
• The emission-based method significantly reduced attenuation artifacts in phantom and simulation studies.
• Clinical application in 20 myocardial perfusion studies led to interpretation changes in nine patients.

Conclusions:

• An emission-based attenuation map can be generated using fixed values, replacing direct measurements.
• This technique is an inexpensive, hardware-independent alternative to transmission-based correction methods.
• Applicable to all single-photon emission computed tomographic systems, it offers a major advantage.