Intravascular photoacoustic imaging at 1.7 lm spectral band has shown promising capabilities for lipid-rich vulnerable atherosclerotic plaque detection. In this work, we report a high speed catheterbased integrated intravascular photoacoustic/intravascular ultrasound (IVPA/IVUS) imaging system with a 500 Hz optical parametric oscillator laser at 1725 nm. A lipid-mimicking phantom and atherosclerotic rabbit abdominal aorta were imaged at 1 frame per second, which is two orders of magnitude faster than previously reported in IVPA imaging with the same wavelength. Clear photoacoustic signals by the absorption of lipid rich deposition demonstrated the ability of the system for high speed vulnerable atherosclerotic plaques detection. V C 2015 AIP Publishing LLC.[http://dx.doi.org/10.1063/1.4929584] Acute cardiovascular events are mostly due to blood clots or thrombus induced by the sudden rupture of vulnerable atherosclerotic plaques within the coronary artery wall. 1,2Thin-cap fibroatheroma (TCFA) has a large, lipid-rich, necrotic core, which has been demonstrated as a primary type of vulnerable atherosclerotic plaque with a high risk to ruptures.3-5 Accurate quantification of both the morphology and composition of a plaque are essential for early detection and optimal treatment in clinics. Several catheter-based intravascular imaging techniques have been investigated. Intravascular ultrasound (IVUS) has been widely used in clinics 4-6 and provides structural information of the atherosclerotic plaque with good penetration depth and axial resolutions of approximately 70 lm. However, the contrast between the lipid-rich region and other soft tissues is limited.6-8 Optical coherence tomography (OCT) has a higher axial resolution of $10 lm, which is ideal for thin fibrous cap thickness measurements, but the penetration depth is less than 2 mm and generally requires blood to be flushed from the imaging area.9,10 Intravascular near-infrared reflection spectroscopy (NIRS) identifies the presence of lipid-rich plaque by detection of the reflection spectrum of the vascular wall, but lacks depth resolution. 11,12Photoacoustic (PA) imaging is a hybrid imaging technique that detects the ultrasound signals generated by the absorption of short pulsed laser inside tissue.13-15 Based on the optical absorption contrast of the tissues within the vessel wall, intravascular photoacoustic (IVPA) imaging for characterizing plaque compositions has been studied. [16][17][18][19][20][21][22][23][24][25][26][27] Recently, due to the high optical absorption by first overtone of C-H bonds around 1720 nm, IVPA imaging of lipid-rich atherosclerotic plaque at 1.7 lm spectral band has been attracting great attention. 21,28 However, current IVPA imaging speed is limited by the repetition rate of commercial nanosecond lasers at 1.7 lm. Using a laser with 10 Hz repetition rate, one cross-sectional image requires tens of seconds to finish, which limits the translation of the technology for in vivo application. 16,18,21,23,24 In this letter, we report o...

Rationale: Subglottic edema and acquired subglottic stenosis are potentially airway-compromising sequelae in neonates following endotracheal intubation. At present, no imaging modality is capable of in vivo diagnosis of subepithelial airway wall pathology as signs of intubation-related injury.Objectives: To use Fourier domain long-range optical coherence tomography (LR-OCT) to acquire micrometer-resolution images of the airway wall of intubated neonates in a neonatal intensive care unit setting and to analyze images for histopathology and airway wall thickness.Methods: LR-OCT of the neonatal laryngotracheal airway was performed a total of 94 times on 72 subjects (age, 1-175 d; total intubation, 1-104 d). LR-OCT images of the airway wall were analyzed in MATLAB. Medical records were reviewed retrospectively for extubation outcome. Measurements and Main Results:Backward stepwise regression analysis demonstrated a statistically significant association between log(duration of intubation) and both laryngeal (P , 0.001; multiple r 2 = 0.44) and subglottic (P , 0.001; multiple r 2 = 0.55) airway wall thickness. Subjects with positive histopathology on LR-OCT images had a higher likelihood of extubation failure (odds ratio, 5.9; P = 0.007). Longer intubation time was found to be significantly associated with extubation failure.Conclusions: LR-OCT allows for high-resolution evaluation and measurement of the airway wall in intubated neonates. Our data demonstrate a positive correlation between laryngeal and subglottic wall thickness and duration of intubation, suggestive of progressive soft tissue injury. LR-OCT may ultimately aid in the early diagnosis of postintubation subglottic injury and help reduce the incidences of failed extubation caused by subglottic edema or acquired subglottic stenosis in neonates.Clinical trial registered with www.clinicaltrials.gov (NCT 00544427).

Objectives/Hypothesis To evaluate for the first time the feasibility and methodology of long-range Fourier domain optical coherence tomography (LR-OCT) imaging of the internal nasal valve (INV) area in healthy individuals. Study Design Prospective individual cohort study. Methods For 16 individuals, OCT was performed in each nare. The angle and the cross-sectional area of the INV were measured. OCT images were compared to corresponding digital pictures recorded with a flexible endoscope. Results INV angle measured by OCT was found to be 18.3° ± 3.1° (mean ± standard deviation). The cross-sectional area was 0.65 ± 0.23 cm2. The INV angle measured by endoscopy was 18.8° ± 6.9°. There was no statistically significant difference between endoscopy and OCT concerning the mean INV angle (P = .778), but there was a significant difference in test precision (coefficient of variance 50% vs. 15%; P < .001). Conclusions LR-OCT proved to be a fast and easily performed method. OCT could accurately quantify the INV area. The values of the angle and the cross-sectional area of the INV were reproducible and correlated well with the data seen with other methods. Changes in size could be reliably delineated. Endoscopy showed similar values but was significantly less precise.

2b. Laryngoscope, 128:E105-E110, 2018.