Label-free photoacoustic microscopy of myocardial sheet architecture.
Cardiac myofibers are organized into sheet architectures, which contribute to up to 40% of the heart wall thickening for ejection of blood for circulation. It is important to delineate the sheet architecture for a better understanding of cardiac mechanisms. However, current sheet imaging technologies are limited by fixation-induced dehydration/deformation and low spatial resolution. Here we implemented high-resolution label-free photoacoustic microscopy (PAM) of the myocardial sheet architecture. With high endogenous optical-absorption contrast originating mainly from cytochrome, myoglobin, and melanin, PAM can image the unfixed, unstained and unsliced heart without introducing deformation artifacts. A fresh blood-free mouse heart was imaged by PAM ex vivo. The three-dimensional branching sheets were clearly identified within 150 [micro sign]m depth. Various morphological parameters were derived from the PAM image. The sheet thickness (80 ± 10 μm) and the cleavage height (11 ± 1 μm) were derived from an undehydrated heart for the first time. Therefore, PAM has the potential for the functional imaging of sheet architecture in ex vivo perfused and viable hearts.
Chi
C
Zhang
Ya-Jian
YJ
Cheng
Junjie
J
Chen
Samuel
S
Wickline
Lihong V
LV
Wang
D000162:Acoustics; D000818:Animals; D002319:Cardiovascular System; D003580:Cytochromes / Q000378:metabolism; D003952:Diagnostic Imaging / Q000379:methods; D004285:Dogs; D006321:Heart / Q000502:physiology; D021621:Imaging, Three-Dimensional / Q000379:methods; D008543:Melanins / Q000378:metabolism; D051379:Mice; D033401:Microscopy, Acoustic / Q000379:methods*; D009206:Myocardium / Q000473:pathology*; D009210:Myofibrils / Q000473:pathology*; D009211:Myoglobin / Q000378:metabolism; D061088:Photoacoustic Techniques / Q000379:methods*
D003580:Cytochromes; D008543:Melanins; D009211:Myoglobin