Evaluation of the effect of breast implants on the accuracy of the CT attenuation Correction (CTAC) map for SPECT/CT myocardial perfusion imaging: a phantom study

Background: Myocardial perfusion imaging (MPI) using single photon emission computedtomography (SPECT) imaging can assess myocardial viability and perfusion. However,overlying thoracic structures, such as ribs or breast tissue lead to gamma ray attenuation. Thisattenuation does not occur equally for all body regions. Photons emitted from deeper structureswill undergo more attenuation than superficial structures, causing artefacts within the imagethat can mimic pathology - such as ischaemia. Such artefacts can be removed or minimised byusing attenuation correction (AC) maps generated using computed tomography (CT). Breastimplants that have density higher than normal breast tissue, could affect the accuracy of the CTnumbers used for AC.Methods: Imaging protocols were compared with and without three sizes of breast implant, ina phantom study. The first experiment used a diagnostic CT scanner to design the method. Thesecond experiment was carried out in a clinical centre using the CT components of a SPECT/CTscanner to assess the impact of three different breast implants on CT number accuracy whenthe CTAC is applied in SPECT/CT MPI. The last experiment used a clinical SPECT/CTscanner and 99mTC as a radiotracer to mimic the clinical MPI scan.Results: The first and second experiments found that large breast implants led to a greaterdifference in CT HU and CT numbers compared to baseline, than the small or medium implants,but the differences were within the tolerance range (±5HUs). This suggested that even largebreast implants did not impact in a clinically significant way on the accuracy of CT HUs andCT numbers. However, the third experiment found that large breast implants resulted in a moresignificant difference in corrected counts and thus more overcorrection than small or mediumbreast implants.Conclusion: The study illustrates that large breast implants resulted in a greater differences inCT HUs, CT number and corrected counts than small or medium implants. Increasing the tubecurrent (mA) improves the CT HU accuracy without significant impact, apart from an increasein the radiation dose to the patient.

Level dc:type.qualificationlevel

Doctoral (Level 8)

Year dc:date.issued

2022

Author dc:creator

• Alanezi, A

Language dc:language

en

Identifier

oai:salford-repository.worktribe.com:1320870

OAI identifier oai:identifier

oai:salford-repository.worktribe.com:1320870