Browsing by Author "Wang, Pu"

Now showing 1 - 10 of 15
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    Assessing breast tumor margin by multispectral photoacoustic tomography
    (Optical Society of America, 2015-03-12) Li, Rui; Wang, Pu; Lan, Lu; Lloyd Jr., Frank P.; Goergen, Craig J.; Chen, Shaoxiong; Cheng, Ji-Xin; Department of Pathology and Laboratory Medicine, IU School of Medicine
    An unmet need exists in high-speed and highly-sensitive intraoperative assessment of breast cancer margin during conservation surgical procedures. Here, we demonstrate a multispectral photoacoustic tomography system for breast tumor margin assessment using fat and hemoglobin as contrasts. This system provides ~3 mm tissue depth and ~125 μm axial resolution. The results agreed with the histological findings. A high sensitivity in margin assessment was accomplished, which opens a compelling way to intraoperative margin assessment.
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    Assessment of white matter loss using bond-selective photoacoustic imaging in a rat model of contusive spinal cord injury
    (Mary Ann Liebert, 2014-12-15) Wu, Wei; Wang, Pu; Cheng, Ji-Xin; Xu, Xiao-Ming; Department of Neurological Surgery, IU School of Medicine
    White matter (WM) loss is a critical event after spinal cord injury (SCI). Conventionally, such loss has been measured with histological and histochemical approaches, although the procedures are complex and may cause artifact. Recently, coherent Raman microscopy has been proven to be an emerging technology to study de- and remyelination of the injured spinal cord; however, limited penetration depth and small imaging field prevent it from comprehensive assessments of large areas of damaged tissues. Here, we report the use of bond-selective photoacoustic (PA) imaging with 1730-nm excitation, where the first overtone vibration of CH2 bond is located, to assess WM loss after a contusive SCI in adult rats. By employing the first overtone vibration of CH2 bond as the contrast, the mapping of the WM in an intact spinal cord was achieved in a label-free three-dimensional manner, and the physiological change of the spinal cord before and after injury was observed. Moreover, the recovery of the spinal cord from contusive injury with the treatment of a neuroprotective nanomedicine ferulic-acid-conjugated glycol chitosan (FA-GC) was also observed. Our study suggests that bond-selective PA imaging is a valuable tool to assess the progression of WM pathology after SCI as well as neuroprotective therapeutics in a label-free manner.
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    A fiber optoacoustic guide with augmented reality for precision breast-conserving surgery
    (Springer Nature, 2018-05-18) Lan, Lu; Xia, Yan; Li, Rui; Liu, Kaiming; Mai, Jieying; Medley, Jennifer Anne; Obeng-Gyasi, Samilia; Han, Linda K.; Wang, Pu; Cheng, Ji-Xin; Radiology and Imaging Sciences, School of Medicine
    Lumpectomy, also called breast-conserving surgery, has become the standard surgical treatment for early-stage breast cancer. However, accurately locating the tumor during a lumpectomy, especially when the lesion is small and nonpalpable, is a challenge. Such difficulty can lead to either incomplete tumor removal or prolonged surgical time, which result in high re-operation rates (~25%) and increased surgical costs. Here, we report a fiber optoacoustic guide (FOG) with augmented reality (AR) for sub-millimeter tumor localization and intuitive surgical guidance with minimal interference. The FOG is preoperatively implanted in the tumor. Under external pulsed light excitation, the FOG omnidirectionally broadcasts acoustic waves through the optoacoustic effect by a specially designed nano-composite layer at its tip. By capturing the acoustic wave, three ultrasound sensors on the breast skin triangulate the FOG tip's position with 0.25-mm accuracy. An AR system with a tablet measures the coordinates of the ultrasound sensors and transforms the FOG tip's position into visual feedback with <1-mm accuracy, thus aiding surgeons in directly visualizing the tumor location and performing fast and accurate tumor removal. We further show the use of a head-mounted display to visualize the same information in the surgeons' first-person view and achieve hands-free guidance. Towards clinical application, a surgeon successfully deployed the FOG to excise a "pseudo tumor" in a female human cadaver. With the high-accuracy tumor localization by FOG and the intuitive surgical guidance by AR, the surgeon performed accurate and fast tumor removal, which will significantly reduce re-operation rates and shorten the surgery time.
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    High-sensitivity intravascular photoacoustic imaging of lipid-laden plaque with a collinear catheter design
    (SpringerNature, 2016-04-28) Cao, Yingchun; Hui, Jie; Kole, Ayeeshik; Wang, Pu; Yu, Qianhuan; Chen, Weibiao; Sturek, Michael; Cheng, Ji-Xin; Department of Cellular & Integrative Physiology, IU School of Medicine
    A highly sensitive catheter probe is critical to catheter-based intravascular photoacoustic imaging. Here, we present a photoacoustic catheter probe design on the basis of collinear alignment of the incident optical wave and the photoacoustically generated sound wave within a miniature catheter housing for the first time. Such collinear catheter design with an outer diameter of 1.6 mm provided highly efficient overlap between optical and acoustic waves over an imaging depth of >6 mm in D2O medium. Intravascular photoacoustic imaging of lipid-laden atherosclerotic plaque and perivascular fat was demonstrated, where a lab-built 500 Hz optical parametric oscillator outputting nanosecond optical pulses at a wavelength of 1.7 μm was used for overtone excitation of C-H bonds. In addition to intravascular imaging, the presented catheter design will benefit other photoacoustic applications such as needle-based intramuscular imaging.
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    High-speed intravascular photoacoustic imaging at 1.7 μm with a KTP-based OPO
    (The Optical Society, 2015-11-01) Hui, Jie; Yu, Qianhuan; Ma, Teng; Wang, Pu; Cao, Yingchun; Bruning, Rebecca S.; Qu, Yueqiao; Chen, Zhongping; Zhou, Qifa; Sturek, Michael; Cheng, Ji-Xin; Chen, Weibiao; Department of Cellular & Integrative Physiology, IU School of Medicine
    Lipid deposition inside the arterial wall is a hallmark of plaque vulnerability. Based on overtone absorption of C-H bonds, intravascular photoacoustic (IVPA) catheter is a promising technology for quantifying the amount of lipid and its spatial distribution inside the arterial wall. Thus far, the clinical translation of IVPA technology is limited by its slow imaging speed due to lack of a high-pulse-energy high-repetition-rate laser source for lipid-specific first overtone excitation at 1.7 μm. Here, we demonstrate a potassium titanyl phosphate (KTP)-based optical parametric oscillator with output pulse energy up to 2 mJ at a wavelength of 1724 nm and with a repetition rate of 500 Hz. Using this laser and a ring-shape transducer, IVPA imaging at speed of 1 frame per sec was demonstrated. Performance of the IVPA imaging system's resolution, sensitivity, and specificity were characterized by carbon fiber and a lipid-mimicking phantom. The clinical utility of this technology was further evaluated ex vivo in an excised atherosclerotic human femoral artery with comparison to histology.
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    High-speed intravascular photoacoustic imaging of lipid-laden atherosclerotic plaque enabled by a 2-kHz barium nitrite raman laser
    (Nature Publishing Group, 2014-11-04) Wang, Pu; Ma, Teng; Slipchenko, Mikhail N.; Liang, Shanshan; Hui, Jie; Shung, Kirk; Roy, Sukesh; Sturek, Michael; Zhou, Qifa; Chen, Zhongping; Cheng, Ji-Xin; Cellular & Integrative Physiology, School of Medicine
    Lipid deposition inside the arterial wall is a key indicator of plaque vulnerability. An intravascular photoacoustic (IVPA) catheter is considered a promising device for quantifying the amount of lipid inside the arterial wall. Thus far, IVPA systems suffered from slow imaging speed (~50 s per frame) due to the lack of a suitable laser source for high-speed excitation of molecular overtone vibrations. Here, we report an improvement in IVPA imaging speed by two orders of magnitude, to 1.0 s per frame, enabled by a custom-built, 2-kHz master oscillator power amplifier (MOPA)-pumped, barium nitrite [Ba(NO3)2] Raman laser. This advancement narrows the gap in translating the IVPA technology to the clinical setting.
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    Highly Sensitive Intravascular Photoacoustic Imaging with a Collinear Catheter Probe
    (OSA, 2016-06) Cao, Yingchun; Hui, Jie; Kole, Ayeeshik; Wang, Pu; Chen, Weibiao; Sturek, Michael; Cheng, Ji-Xin; Department of Cellular and Integrative Physiology, School of Medicine
    A collinear catheter for label-free intravascular photoacoustic imaging was developed with a diameter of 1.6 mm. The collinear overlap between optical and acoustic waves enabled photoacoustic imaging of a human coronary artery from lumen to perivascular fat.
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    High‐speed Intraoperative Assessment of Breast Tumor Margins by Multimodal Ultrasound and Photoacoustic Tomography
    (Wiley, 2018) Lu, Rui; Lan, Lu; Xia, Yan; Wang, Pu; Han, Linda K.; Dunnington, Gary L.; Obeng-Gyasi, Samilia; Sandusky, George E.; Medley, Jennifer A.; Crook, Susan T.; Cheng, Ji-Xin; Medicine, School of Medicine
    Conventional methods for breast tumor margins assessment need a long turnaround time, which may lead to re‐operation for patients undergoing lumpectomy surgeries. Photoacoustic tomography (PAT) has been shown to visualize adipose tissue in small animals and human breast. Here, we demonstrate a customized multimodal ultrasound and PAT system for intraoperative breast tumor margins assessment using fresh lumpectomy specimens from 66 patients. The system provides the margin status of the entire excised tissue within 10 minutes. By subjective reading of three researchers, the results show 85.7% [95% confidence interval (CI), 42.0% ‐ 99.2%] sensitivity and 84.6% (95% CI, 53.7% ‐ 97.3%) specificity, 71.4% (95% CI, 30.3% ‐ 94.9%) sensitivity and 92.3% (95% CI, 62.1% ‐ 99.6%) specificity, and 100% (95% CI, 56.1% ‐ 100%) sensitivity and 53.9% (95% CI, 26.1% ‐ 79.6%) specificity respectively when cross‐correlated with post‐operational histology. Furthermore, a machine learning‐based algorithm is deployed for margin assessment in the challenging ductal carcinoma in situ tissues, and achieved 85.5% (95% CI, 75.2% ‐ 92.2%) sensitivity and 90% (95% CI, 79.9% ‐ 95.5%) specificity. Such results present the potential of using mutlimodal ultrasound and PAT as a high‐speed and accurate method for intraoperative breast tumor margins evaluation.
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    Impact of Artificial Intelligence on Colonoscopy Surveillance After Polyp Removal: A Pooled Analysis of Randomized Trials
    (Elsevier, 2023) Mori, Yuichi; Wang, Pu; Løberg, Magnus; Misawa, Masashi; Repici, Alessandro; Spadaccini, Marco; Correale, Loredana; Antonelli, Giulio; Yu, Honggang; Gong, Dexin; Ishiyama, Misaki; Kudo, Shin-ei; Kamba, Shunsuke; Sumiyama, Kazuki; Saito, Yutaka; Nishino, Haruo; Liu, Peixi; Glissen Brown, Jeremy R.; Mansour, Nabil M.; Gross, Seth A.; Kalager, Mette; Bretthauer, Michael; Rex, Douglas K.; Sharma, Prateek; Berzin, Tyler M.; Hassan, Cesare; Medicine, School of Medicine
    Background and aims: Artificial intelligence (AI) tools aimed at improving polyp detection have been shown to increase the adenoma detection rate during colonoscopy. However, it is unknown how increased polyp detection rates by AI affect the burden of patient surveillance after polyp removal. Methods: We conducted a pooled analysis of 9 randomized controlled trials (5 in China, 2 in Italy, 1 in Japan, and 1 in the United States) comparing colonoscopy with or without AI detection aids. The primary outcome was the proportion of patients recommended to undergo intensive surveillance (ie, 3-year interval). We analyzed intervals for AI and non-AI colonoscopies for the U.S. and European recommendations separately. We estimated proportions by calculating relative risks using the Mantel-Haenszel method. Results: A total of 5796 patients (51% male, mean 53 years of age) were included; 2894 underwent AI-assisted colonoscopy and 2902 non-AI colonoscopy. When following U.S. guidelines, the proportion of patients recommended intensive surveillance increased from 8.4% (95% CI, 7.4%-9.5%) in the non-AI group to 11.3% (95% CI, 10.2%-12.6%) in the AI group (absolute difference, 2.9% [95% CI, 1.4%-4.4%]; risk ratio, 1.35 [95% CI, 1.16-1.57]). When following European guidelines, it increased from 6.1% (95% CI, 5.3%-7.0%) to 7.4% (95% CI, 6.5%-8.4%) (absolute difference, 1.3% [95% CI, 0.01%-2.6%]; risk ratio, 1.22 [95% CI, 1.01-1.47]). Conclusions: The use of AI during colonoscopy increased the proportion of patients requiring intensive colonoscopy surveillance by approximately 35% in the United States and 20% in Europe (absolute increases of 2.9% and 1.3%, respectively). While this may contribute to improved cancer prevention, it significantly adds patient burden and healthcare costs.
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    Investigation of the separation dependent fluorescence resonant energy transfer between CdSe/ZnS quantum dots by near-field scanning optical microscopy
    (2010-02-02T17:37:27Z) Wang, Pu; Naumann, Christof A.; Dunn, Kenneth William; Decca, Ricardo S.; Atkinson, Susan J.
    A Near-field Scanning Optical Microscope (NSOM) is used to study the resonant energy transfer between different size CdSe/ZnS quantum dots (QDs). The NSOM system is used to bring the small QDs which are 6 nm in diameter close to 8 nm diameter QDs which are embed with PMMA on a cover glass. The PMMA is used to prevent the 8 nm QDs from aggregation, which allows us to locate one dot on the cover slide and have the potential to get the interaction of two individual dots. A systematic methodology is used to localize a single QD on the cover glass and align the small and large QDs. Since the ground energy state of the small QDs match the excitation energy level of the large QDs. When the small dots get excited, part of the energy transfers to the large QDs. As the separation between small and large QDs is changed in near-field range (20-50nm), the transition probability is observed, indicating that the FRET level changes as a function of separation between small and large QDs. Possible future improvements are also discussed.