Cardiac PET/MRI—an update

Abstract

It is now about 8 years since the first whole-body integrated PET/MRI has been installed. First, reports on technical characteristics and system performance were published. Early after, reports on the first use of PET/MRI in oncological patients were released. Interestingly, the first article on the application in cardiology was a review article, which was published before the first original article was put out. Since then, researchers have gained a lot experience with the PET/MRI in various cardiovascular diseases and an increasing number on auspicious indications is appearing. In this review article, we give an overview on technical updates within these last years with potential impact on cardiac imaging and summarize those scenarios where PET/MRI plays a pivotal role in cardiovascular medicine.

Complete estamation of patient with myocardial ischemia

“…виталитет В този случай съчетанието на двата метода може да диференцира нормалните зони от тези с нарушена перфузия и липсващ метаболизъм (цикатрикс) от такива с нарушена перфузия и наличен метаболизъм (хронична исхемия, хибернация). Съвременните апарати дават възможност да се получат "слети" образи от двата метода с точна визуализация на проблемната зона и дори нейното количествено измерване от ЯМР образ [19].…”

“…Накратко, неинвазивните методи са ядрено-магнитен резонанс, SPECT, КТ, РЕТ с радомаркер за кръвоток/перфузия, както и навлезлите напоследък комбинирани "слети" (fusion) образи между тях. Принципът е количествено или полуколичествено сравняване на миокардната перфузия преди и след приложението на хиперемизиращ медикамент -най-често аденозин, или в по-старите проучвания -дипиридамол [15][16][17][18][19].…”

Cardiac MRI and Myocardial Injury in COVID-19: Diagnosis, Risk Stratification and Prognosis

“…FDG PET/MR may have incremental value for the evaluation of myocarditis compared to CMR alone, particularly in the early stages of inflammation, and to potentially differentiate active inflammation from scars; however, more large-center trials are needed. This modality is also limited by availability and cost [ 60 , 61 ]. CMR is an invaluable tool not only for diagnosis, but also for prognosis in acute myocarditis.…”

Cardiac PET/MR: Are sophisticated attenuation correction techniques necessary for clinical routine assessments?

“…Resonance Imaging (PET/MR) has gained significant interest since the introduction of the integrated PET/MR systems in 2011. [1][2][3] One of the strengths of the hybrid PET/MR systems is the potential for sophisticated cardiorespiratory motion correction of the PET data utilizing well-defined motion vector fields obtained from dedicated MR sequences. [4][5][6] In contrast, current applications in PET/CT systems face challenges in the motion correction, which often is based on gated image reconstructions, with high noise and much lower spatial resolution and contrast, when compared to MR images.…”

“…8 Both MR sequences require acquisition times of up to 18 seconds per bed position and, thus, have increased risks of having motion artifacts (blurring and misalignment) because of respiratory motion during the acquisition. 3,8,9 These artifacts may translate into streak artifacts in the PET images, misalignment artifacts between the MR-AC maps and the PET emission data, and finally tissue misclassifications. [9][10][11][12] A recent study evaluated the impact of using alternative sequences for the MR-AC maps, with the acquisition protocols based on a multi-echo stack-ofstars gradient echo sequence, which has been proven to be less affected by the cardiorespiratory motion during the acquisition.…”