Quantitative investigation of vascular response to mesenteric venous thrombosis using large‐field‐of‐view photoacoustic microscopy

Abstract

Mesenteric venous thrombosis (MVT) is one of major causes leading to severe mesenteric ischemia. Vascular network plays an important role during the occurrence and development of MVT. However, there lacks an appropriate imaging method, which features advanced volumetric resolving capability, superior sensitivity to hemoglobin, and ultra‐large field‐of‐view (FOV), to investigate vascular response of MVT. In this study, we developed and applied a large‐FOV optical resolution photoacoustic microscopy to quantify the vascular response during the entire course of two different MVT models in which we ligated the superior mesenteric vein and inferior mesenteric vein, respectively. Furthermore, we developed a quantitative algorithm to derive total vascular length, relative concentration of total hemoglobin and vascular density over the FOV to reveal different vascular responses in different MVT models.

Organ‐PAM: Photoacoustic Microscopy of Whole‐organ Multiset Vessel Systems

“…Figure S9a, Supporting Information demonstrates the data processing for vessel system quantification of a typical 2D vessel image adapted from previous works. [ 29 ] To precisely perform quantitative analysis, first the system's responding map acquired by imaging a homogeneous light absorber was utilized to correct the 2D MAP images. Then, denoising and vessel system segmentation were performed through threshold adjusting to eliminate unwanted PAI signals.…”

“…[28] Previously, we reported a rotary scanning mechanism achieved by using a combination of a 2D optical scanner and a DC rotator, which can effectively eliminate the limitations of conventional raster scanning and reach a larger lateral FOV of up to 40 mm. [25,29] Yet, the FOV of a single rotary scan is still insufficient for whole organ imaging of large animals and primates. To further extend the lateral FOV, we motorized the sample holder with two linear stages, carried out multiple rotary scans in a raster pattern, stitched images according to the roving sequence, and finally obtained an effective lateral FOV of 95 mm × 95 mm, which is tenfold larger than that of conventional PAMs.…”

Progress of clinical translation of handheld and semi-handheld photoacoustic imaging

“…Over the last two decades, PAI has been used in numerous studies such as whole body imaging of small animals [ 3 , 21 , 22 ], in vivo vascular imaging in various organs of rodents and primates [ 23 , 24 ], and studying neurovascular coupling [ 25 , 26 ]. In addition, potential clinical applications include angiogenesis and vascular distribution inside/around tumors [ 27 , 28 ], retinal vasculature associated with diabetic retinopathy [ 29 , 30 ], intestinal diseases such as Crohn’s disease and mesenteric venous thrombosis [ 31 , 32 ], vascular lipid plaque [ 33 , 34 ], and breast cancer [ 27 , [35] , [36] , [37] ] as shown in Table 1 . Although PAI has multi-scale and multi-parametric imaging capability with various advanced features, early-stage PAI systems suffer from several limitations.…”

Photoacoustic imaging in evaluating early intestinal ischemia injury and reperfusion injury in rat models

“…PAI is a hybrid imaging method that combines optical contrast and ultrasonic resolution (11,12). It combines high-resolution volume imaging of tissue depths from a few millimeters to centimeters with the ability to analyze drugs with molecular specificity and vascular system and physiological parameters (13). PAI is particularly suitable for vascular imaging because the high concentration of hemoglobin in the blood can achieve strong absorption and produce high contrast with surrounding tissues (14,15).…”