High-resolution Real-time Imaging Research Articles

Dynamic imaging of accommodation by swept-source anterior segment optical coherence tomography

To study the accommodation process in normal eyes using a commercially available clinical system based on swept-source anterior segment optical coherence tomography (AS-OCT). Ophthalmology Department, University of Parma, Italy. Evaluation of diagnostic technology. Right eyes were analyzed using swept-source AS-OCT (Casia SS-1000). The optical vergence of the internal coaxial fixation target was adjusted during imaging to obtain monocular accommodation stimuli with different amplitudes (0, 3.0, 6.0, and 9.0 diopters [D]). Overlapping of real and conjugate OCT images enabled imaging of all the anterior segment optical surfaces in a single frame. Central corneal thickness (CCT), anterior chamber depth (ACD), and lens thickness were extracted from the OCT scans acquired at different static accommodation stimulus amplitudes. The crystalline lens was analyzed dynamically during accommodation and disaccommodation by acquiring sequential OCT images of the anterior segment at a rate of 8 frames per second. The lens thickness was extracted from the temporal sequence of OCT images and plotted as a function of time. The study analyzed 14 eyes of 14 subjects aged 18 to 46 years. During accommodation, the decrease in the ACD was statistically significant (P < .05), as were the increase in the lens thickness (P < .001) and the slight movement forward of the lens central point (P < .01). The CCT and anterior chamber width measurements did not change statistically significantly during accommodation. The lens thickness at 0 D was positively correlated with age (P < .01). High-resolution real-time imaging and biometry of the accommodating anterior segment can be effectively performed using a commercially available swept-source AS-OCT clinical device. No author has a financial or proprietary interest in any material or method mentioned.

Mechanical Stabilization of Mouse Carotid Artery for In Vivo Intravital Microscopy Imaging of Atherogenesis.

We present here a procedure that allows real-time high-resolution multichannel imaging of early atherosclerotic lesions of live mice, by dramatically reducing the respiratory and pulsatile movements of the athero-susceptible carotid artery, without significantly altering blood flow dynamics. This surgical preparation can be combined with the use of various fluorescent probes and reporter mice to simultaneously visualize the dynamics of inflammatory leukocytes, platelets, or even subcellular structures. Stabilization of the tissue renders it suitable for two-photon laser scanning microscopic imaging and allows tracking the behavior of inflammatory cells in three dimensions.

The Research of the Real-Time High-Resolution Image Acquisition Based on Embedded System

This paper presents the design of a real-time high-definition image acquisition. The hardware platform combines Intel Xscale PXA270 processor, high-resolution camera and SAA7114H. The system is based on the embedded Linux system. Beetween the image sensor and the system memory,there is a quick capture interface.The interface receives the data from the image sensor,and converts the raw image data to a suitable format, and sends H.264 stream to the memory via the DMA channel. The result shows that the design can realize the real-time and high-definition image acquisition in a complicated environment. The advantage of this system is small volume, low power consumption and low cost. It can be widely used in agricultural and hydrological monitoring, intelligent transportation, security monitoring and intelligent home.

고해상도 CCTV 카메라를 위한 빠른 사람 검출 알고리즘

본 논문은 사람 검출 알고리즘을 고해상도 CCTV 카메라에 적용할 수 있도록 빠른 사람 검출 알고리즘을 제안한다. HOG 디텍터를 이용한 사람 검출 알고리즘은 영상처리 분야의 최신 기술로 높은 성능을 보인다. 그러나 HOG 특징 추출과정에서 연산 속도가 느려 실시간 고해상도 영상에 적용하기 어렵다. 이러한 문제를 해결하기 위해 2단계 검출 방법을 제안한다. 먼저 전처리 과정으로 배경 차감법(Background subtraction)을 이용하여 사람 후보 영역을 찾는다. 이후 사람 후보영역에서만 HOG 디텍터를 이용하여 사람/비사람 구분을 수행한다. 이러한 두 단계의 실험 결과 약 2.5배의 검출 속도 향상을 보였으며, 성능 저하는 거의 없음을 확인할 수 있었다. This paper suggests a fast human detection algorithm that can be applied to a high-resolution CCTV camera. Human detection algorithms, which used a HOG detector show high performance in the region of image processing. On the other hand, it is difficult to apply to real-time high resolution imaging because of its slow processing speed in the extracting figures of HOG. To resolve this problems, we suggest how to detect humans into two stages. First, candidates of a human region are found using background subtraction, and humans and non-humans are distinguished using a HOG detector only. This process increases the detection speed by approximately 2.5 times without any degradation in performance.

Manifold learning based ECG-free free-breathing cardiac CINE MRI.

To present and validate a manifold learning (ML)-based method that can estimate both cardiac and respiratory navigator signals from electrocardiogram (ECG)-free free-breathing cardiac magnetic resonance imaging (MRI) data to achieve self-gated retrospective CINE reconstruction. In this work the use of the ML method is demonstrated for 2D cardiac CINE to achieve both cardiac and respiratory self-gating without the need of an external navigator or ECG signal. This is achieved by sequentially applying ML to two sets of retrospectively reconstructed real-time images with differing temporal resolutions. A 1D cardiac signal is estimated by applying ML to high temporal resolution real-time images reconstructed from the acquired data. Using the estimated cardiac signal, a 1D respiratory signal was obtained by applying the ML method to low temporal resolution images reconstructed from the same acquired data for each cardiac cycle. Data were acquired in five volunteers with a 2D golden angle radial trajectory in a balanced steady-state free precession (b-SSFP) acquisition. The accuracy of the estimated cardiac signal was calculated as the standard deviation of the temporal difference between the estimated signal and the recorded ECG. The correlation between the estimated respiratory signal and standard pencil beam navigator signal was evaluated. Gated CINE reconstructions (20 cardiac phases per cycle, temporal resolution ∼30 msec) using the estimated cardiac and respiratory signals were qualitatively compared against conventional ECG-gated breath-hold CINE acquisitions. Accurate cardiac signals were estimated with the proposed method, with an error standard deviation in comparison to ECG lower than 20 msec. Respiratory signals estimated with the proposed method achieved a mean cross-correlation of 94% with respect to standard pencil beam navigator signals. Good quality visual scores of 2.80 ± 0.45 (scores from 0, bad, to 4, excellent quality) were observed for the proposed approach in comparison with the conventional ECG-gated breath-hold images (visual score: 3.00 ± 0.71). Accurate respiratory and cardiac navigator signals can be estimated using the proposed framework from the acquired data itself, resulting in retrospective self-gated CINE reconstruction with high spatial and temporal quality.

Stabilization technique for real-time high-resolution vascular ultrasound using frequency domain interferometry.

We have proposed an ultrasound imaging method based on frequency domain interferometry (FDI) with an adaptive beamforming technique to depict real-time high-resolution images of human carotid artery. Our previous study has investigated the performance of the proposed imaging method under an ideal condition with a high signal-to-noise ratio (SNR). In the present study, we propose a technique that has the potential to improve accuracy in estimating echo intensity using the FDI imaging method. We investigated the performance of the proposed technique in a simulation study that two flat interfaces were located at depths of 15.0 and 15.2 mm and white noise was added. Because the -6 dB bandwidth of the signal used in this simulation study is 2.6 MHz, the conventional B-mode imaging method failed to depict the two interfaces. Both the conventional and proposed FDI imaging methods succeeded to depict the two interfaces when the SNR ranged from 15 to 30 dB. However, the average error of the estimated echo intensity at the interfaces using the conventional FDI imaging method ranged from 7.2 to 10.5 dB. In contrast, that using the FDI imaging method with the proposed technique ranged from 2.0 to 2.2 dB. The present study demonstrates the potential of the FDI imaging method in depicting robust and high-range-resolution ultrasound images of arterial wall, indicating the possibility to improve the diagnosis of atherosclerosis in early stages.

High resolution three-dimensional photoacoutic tomography with CCD-camera based ultrasound detection.

A photoacoustic tomograph based on optical ultrasound detection is demonstrated, which is capable of high resolution real-time projection imaging and fast three-dimensional (3D) imaging. Snapshots of the pressure field outside the imaged object are taken at defined delay times after photoacoustic excitation by use of a charge coupled device (CCD) camera in combination with an optical phase contrast method. From the obtained wave patterns photoacoustic projection images are reconstructed using a back propagation Fourier domain reconstruction algorithm. Applying the inverse Radon transform to a set of projections recorded over a half rotation of the sample provides 3D photoacoustic tomography images in less than one minute with a resolution below 100 µm. The sensitivity of the device was experimentally determined to be 5.1 kPa over a projection length of 1 mm. In vivo images of the vasculature of a mouse demonstrate the potential of the developed method for biomedical applications.

A methodology for the investigation of toughness and crack propagation in mouse bone

Bone fracture is a health concern for those with aged bone and brittle bone diseases. Mouse bone is widely used as a model of human bone, especially to investigate preclinical treatment strategies. However, little is known about the mechanisms of mouse bone fracture and its similarities and differences from fracture in human bone. In this work we present a methodology to investigate the fracture toughness during crack initiation and crack propagation for mouse bone.Mouse femora were dissected, polished on their periosteal surface, notched on the posterior surface at their mid-diaphysis, and tested in three-point bending under displacement control at a rate of 0.1mm/min using an in situ loading stage within an environmental scanning electron microscope.We obtained high-resolution real-time imaging of the crack initiation and propagation in mouse bone. From the images we can measure the crack extension at each step of the crack growth and calculate the toughness of the bone (in terms of stress intensity factor (K) and work to fracture (Wf)) as a function of stable crack length (Δa), thus generating a resistance curve for the mouse bone.The technique presented here provides insight into the evolution of microdamage and the toughening mechanisms that resist crack propagation, which are essential for preclinical development of treatments to enhance bone quality and combat fracture risk.

Video: Common upper extremity injections utilizing musculoskeletal ultrasound.

The purpose of this video article is to demonstrate the use of ultrasound for upper extremity musculoskeletal injections, covering general guidelines, preprocedure planning, needle selection, and basic technique. Several different upper-extremity injections are shown, including joint injections and aspirations, tendon sheath and bursal injections, and percutaneous treatment of calcific tendinitis. Musculoskeletal ultrasound is well suited for imaging-guided injections of the upper extremities. It is readily available, allows for high-resolution real-time imaging of the soft tissues and joints, and is adaptable for patient comfort and positioning. After viewing this video article, the observer should have an understanding of the applications for ultrasound in upper-extremity musculoskeletal interventions and should be able to apply that knowledge to advance their clinical practice.

Optical coherence tomography: a reliable alternative to invasive histological assessment of acute wound healing in human skin?

Gold-standard assessment of acute wound healing has traditionally been through histological analysis of biopsied tissue. However, this process is invasive with recognized side-effects. Optical coherence tomography (OCT) is a noninvasive technique generating high-resolution real-time images of cutaneous architecture. To compare OCT with histological assessment of in vivo acute wound healing and ascertain the level of agreement between modalities for measurement of defined cutaneous structures. Punch biopsies (5mm) were harvested from 50 healthy volunteers. Wounds healed by secondary intention until they were re-excised 7, 14, 21 or 28days later depending on random group allocation. Wounds were assessed weekly for 6weeks using OCT and compared with histological findings derived from time-matched biopsies. Dimensions of four cutaneous structures were measured using both modalities and the level of agreement was established by Bland-Altman analysis. The mean greyscale value (MGV) of the upper reticular dermis was derived from OCT images at all time points. Both techniques showed anatomical congruity in normal and wounded skin with correlating architectural changes associated with inflammatory, proliferative and remodelling wound healing phases. MGV was significantly increased 6weeks after wounding (P=0·001) and may represent a novel measure of wound fibrosis. Despite good association of histomorphometric values with low but consistent bias (range -4·181 to 0·431μm), Bland-Altman plots demonstrated poor agreement between OCT and histology. Optical coherence tomography enabled accurate assessment of healing tissue comparable with histological analysis of biopsy specimens. This noninvasive tool is highly suited to wound assessment and may represent a diagnostic alternative to punch biopsies.

8:45 AM; Abstract No. 236; FEATURED ABSTRACT - Interactive near real-time high resolution imaging for open MR guided interventions using zoom MRI at 1.0 Tesla - initial experience

Purpose: Patients with periacetabular bone destruction and impending or pathologic fractures from metastatic cancer have limited treatment options. Complex acetabular reconstruction can improve mobility, but has a high rate of complications and post-operative morbidity, and can delay chemotherapy and radiation. Through the collaboration of orthopedic oncologists and interventional radiologists, we have developed an alternative, minimally invasive approach to stabilize the pelvis. Materials and Methods: Ten patients underwent percutaneous screw fixation and polymethyl methacrylate augmentation for impending or non-displaced pathologic fractures of the acetabulum due to metastatic disease between 11/2011-5/2013. Ablation was performed when appropriate. Medical records were reviewed for hospital course, ability to receive chemotherapy and radiation, pain, and functional scores before and after surgery based on the Musculoskeletal Tumor Society (MSTS) scoring system. Results: Ten patients with a median age of 57.5 made up our cohort. We had a 100% technical success rate and no major complications. Seven patients received conscious sedation, and 3 general anesthesia. Postoperatively, 9 patients were weightbearing as tolerated, and 1 patient was toe-touch weight bearing. Five patients were discharged within 24 hours of surgery, with a mean hospital stay of 4 days. Nine patients could immediately receive chemotherapy and radiation. The mean preoperative and postoperative MSTS scores were 0.3 vs. 2.7 for pain (5 is normal), and 7.1 vs. 15.2 for the total functional score (30 is normal). Pain and mobility improved for all patients. Conclusion: Percutaneous acetabular stabilization improves the pain, mobility, and quality of life in patients with painful metastatic disease and limited life expectancy. It carries a low risk of complications and allows for earlier chemotherapy and radiation. Therefore, patients with painful impending or pathologic pelvic fractures should be considered for minimally invasive stabilization through our multidisciplinary approach.

Tablet Disintegration Studied by High-Resolution Real-Time Magnetic Resonance Imaging

AbstractThe present work employs recent advances in high-resolution real-time magnetic resonance imaging (MRI) to investigate the disintegration process of tablets containing disintegrants. A temporal resolution of 75ms and a spatial resolution of 80 × 80 μm with a section thickness of only 600 μm were achieved. The histograms of MRI videos were quantitatively analyzed with MATLAB. The mechanisms of action of six commercially available disintegrants, the influence of relative tablet density, and the impact of disintegrant concentration were examined. Crospovidone seems to be the only disintegrant acting by a shape memory effect, whereas the others mainly swell. A higher relative density of tablets containing croscarmellose sodium leads to a more even distribution of water within the tablet matrix but hardly impacts the disintegration kinetics. Increasing the polacrilin potassium disintegrant concentration leads to a quicker and more thorough disintegration process. Real-time MRI emerges as valuable tool to visualize and investigate the process of tablet disintegration. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:249–255, 2014

Pre‐ and post‐training session evaluation for interobserver agreement and diagnostic accuracy of probe‐based confocal laser endomicroscopy for biliary strictures

Current diagnostic modalities for indeterminate biliary strictures offer low accuracy. Probe-based confocal laser endomicroscopy (pCLE) permits microscopic assessment of mucosal structures by obtaining real-time high-resolution images of the mucosal layers of the gastrointestinal tract. Previously, an interobserver study demonstrated poor to fair agreement even among experienced confocal endomicroscopy operators. Our objective was to assess interobserver agreement and diagnostic accuracy upon completion of a pCLE training session. Forty de-identified pCLE video clips of indeterminate biliary strictures were sent to five endoscopists at four tertiary care centers for scoring. Observers subsequently attended a teaching session by an expert pCLE user that included 20 training clips and rescored the same pCLE video clips, which were randomized and renumbered. Pre-training interobserver agreement for all observers was 'fair' (Κ: 0.31, P-value: <0.0001) and diagnostic accuracy was 72% (55-80%). Post-training interobserver agreement for all observers was 'substantial' (Κ: 0.74, P-value: <0.0001) and diagnostic accuracy was 89% (80-95%). Using a paired t-test, we observed an increase of 17% (95% CI 7.6-26.4) in post-training diagnostic accuracy (t = 5.01, df = 4, P-value 0.007). Interobserver agreement and diagnostic accuracy improved after observers underwent training by an expert pCLE user with a specific sequence set. Users should participate in such training programs to maximize diagnostic accuracy of pCLE evaluation.

Technology Focus: Horizontal and Complex-Trajectory Wells (November 2013)

Technology Focus Irrespective of industry or sector, the objectives of innovation are productivity and performance improvement and cost reduction. In the case of horizontal or complex geometry wells, innovation has delivered technologies targeting cost reduction and productivity improvement. While the advantages of these are realized in use, the true value is rarely calculated. As a result, the cycle of slow implementation of new technology continues and the pace of innovation is never optimized. As innovation delivers more technology choices, the well engineer’s work when forming technical recommendations and evaluating performance becomes more complex. Adding further complexity is the fact that combinations of technologies and associated services increasingly interact to deliver secondary benefits, not all of which are immediately obvious. Many of these benefits affect the productivity of a well over its entire life cycle. As a consequence, they become significant, but their overall value is challenging to confidently quantify for consideration. In a conventional operator/service-company relationship, the buyers are frequently cost managers. As a consequence, decisions tend to be biased toward unit cost. Beyond that, the value of a technology selection is normally determined more on the short-term cost saving than on the longer-term asset-added value. For example, saving 2 days of drilling time or eliminating a hole section is sometimes considered more important than a long-term incremental-production benefit over a well’s entire life, even though the cumulative value of the latter may be far greater. While there are exceptions, this is a roadblock to the take-up of new technology. As a consequence, the pace of innovation reduces, slowing productivity or performance improvement. As an industry, we need to consider factors that slow the pace of innovation. These scenarios indicate a need for new levels of competency to evaluate choices and optimize how we apply combinations of technologies. We must improve how technical recommendations are made by using risk-based, true return on investment and not deferring to unit cost or limiting justifications to immediate tangible gains. There is also a case to rethink the traditional cost-biased interfaces and business models between service suppliers and operators. The papers selected this year include examples in which the value of innovation is recognized and steps were taken to optimize application in horizontal wells. Recommended additional reading at OnePetro: www.onepetro.org. IPTC 16872 Production Transformation in Horizontal Wells’ Oil Recovery and Revival in Shallow Volcanic Fractured Reservoir by ICD’s OH Completions Success, Central Thailand by B. Edward, Pan Orient Energy, et al. SPE 164841 Using Real-Time High-Resolution LWD Images To Navigate and Optimize Multistage Completions in a Carbonate Reservoir by Sandeep Janwadkar, Baker Hughes, et al. SPE/IADC 163494 Successful Application of Concentric-Casing Nitrogen Injection To Overcome Drilling Challenges and Deliver a Record Horizontal Well in the Tecominoacan Field by Reginaldo Rodriguez, Pemex, et al.

Multiresolution foveated laparoscope with high resolvability.

A key limitation of the state-of-the-art laparoscopes for minimally invasive surgery is the tradeoff between the field of view and spatial resolution in a single-view camera system. As such, surgical procedures are usually performed at a zoomed-in view, which limits the surgeon's ability to see much outside the immediate focus of interest and causes a situational awareness challenge. We proposed a multiresolution foveated laparoscope (MRFL) aiming to address this limitation. The MRFL is able to simultaneously capture wide-angle overview and high-resolution images in real time; it can scan and engage the high-resolution images to any subregion of the entire surgical field in analogy to the fovea of human eye. The MRFL is able to render equivalently 10 million pixel resolution with a low data bandwidth requirement. The system has a large working distance (WD) from 80 to 180mm. The spatial resolvability is about 45μm in the object space at an 80mm WD, while the resolvability of a conventional laparoscope is about 250μm at a typically 50mm surgical distance.

A Green Synthesis of Carbon Nanoparticle from Honey for Real-Time Photoacoustic Imaging.

Imaging sentinel lymph nodes (SLN) could provide us with critical information about the progression of a cancerous disease. Real-time high-resolution intraoperative photoacoustic imaging (PAI) in conjunction with a near infrared (NIR) probe may offer the opportunities for the immediate imaging for direct identification and resection of SLN or collecting tissue samples. In this work a commercially amenable synthetic methodology is revealed for developing luminescent carbon nanoparticles with rapid clearance properties. A one-pot "green" technique is pursued, which involved rapid surface passivation of carbon nanoparticles with organic macromolecules (e.g. polysorbate, polyethyleneglycol) in a solvent free condition. Interestingly, the naked carbon nanoparticles are derived for the first time, from commercial food grade honey. Surface coated particles are markedly smaller (~7 nm) than the previously explored particles (gold, SWNT, copper) for SLN imaging. Results indicate an exceptionally rapid signal enhancement (~2 min) of the SLN. Owing to their strong optical absorption in the near infrared region, tiny size and rapid lymphatic transport, this platform offers great potential for faster resection of SLN and may lower complications caused by axillary investigation for mismarking with dyes or low-resolution imaging techniques.

Value of indocyanine green videoangiography in deciding the completeness of cerebrovascular surgery.

ObjectiveRecently, microscope-integrated near infrared indocyanine green videoangiography (ICG-VA) has been widely used in cerebrovascular surgery because it provides real-time high resolution images. In our study, we evaluate the efficacy of intraoperative ICG-VA during cerebrovascular surgery.MethodsBetween August 2011 and April 2012, 188 patients with cerebrovascular disease were surgically treated in our institution. We used ICG-VA in that operations with half of recommended dose (0.2 to 0.3 mg/kg). Postoperative digital subtraction angiography and computed tomography angiography was used to confirm anatomical results.ResultsIntraoperative ICG-VA demonstrated fully occluded aneurysm sack, no neck remnant, and without vessel compromise in 119 cases (93.7%) of 127 aneurysms. Eight clipping (6.3%) of 127 operations were identified as an incomplete aneurysm occlusion or compromising vessel after ICG-VA. In 41 (97.6%) of 42 patients after carotid endarterectomy, the results were the same as that of postoperative angiography with good patency. One case (5.9%) of 17 bypass surgeries was identified as a nonfunctioning anastomosis after ICG-VA, which could be revised successfully. In the two patients of arteriovenous malformation, ICG-VA was useful for find the superficial nature of the feeding arteries and draining veins.ConclusionICG-VA is simple and provides real-time information of the patency of vessels including very small perforators within the field of the microscope and has a lower rate of adverse reactions. However, ICG-VA is not a perfect method, and so a combination of monitoring tools assures the quality of cerebrovascular surgery.

3P5-7 Real-time high-resolution ultrasound imaging method using adaptive beamforming technique applied to swine liver in vitro(Poster Session)

3P5-7 Real-time high-resolution ultrasound imaging method using adaptive beamforming technique applied to swine liver in vitro(Poster Session)

3SDA-04 Real-time high-resolution cardiac imaging in vivo(3SDA Biophysics toward In Vivo work,Symposium)

3SDA-04 Real-time high-resolution cardiac imaging in vivo(3SDA Biophysics toward In Vivo work,Symposium)

Real-time near-infrared (NIR) fluorescent cholangiography in single-site robotic cholecystectomy (SSRC): a single-institutional prospective study

Bile duct injury is a rare but serious complication of laparoscopic cholecystectomy and the primary cause is misinterpretation of biliary anatomy. This may occur more frequently with a single-incision approach due to difficulties in exposing and visualizing the triangle of Calot. Intraoperative cholangiography was proposed to overcome this problem, but due to multiple issues, it is not used routinely. Indocyanine green (ICG) near-infrared (NIR) fluorescent cholangiography is non invasive and provides real-time biliary images during surgery, which may improve the safety of single-incision cholecystectomy. This study aims to evaluate the efficacy and safety of this technique during single-site robotic cholecystectomy (SSRC). Patients presenting with symptomatic biliary gallstones without suspicion of common bile duct stones underwent SSRC with ICG-NIR fluorescent cholangiography using the da Vinci Fluorescence Imaging Vision System. During patient preparation, 2.5 mg of ICG was injected intravenously. During surgery, the biliary anatomy was imaged in real time, which guided dissection of Calot's triangle. Perioperative outcomes included biliary tree visualizations, operative time, conversion and complications rates, and length of hospital stay. There were 45 cases between July 2011 and January 2012. All procedures were completed successfully; there were no conversions and at least one structure was visualized in each patient. The rates of visualization were 93 % for the cystic duct, 88 % for the common hepatic duct, and 91 % for the common bile duct prior to Calot's dissection; after Calot's dissection, the rates were 97 % for all three ducts. Mean hospital stay was 1.1 days and there were no bile duct injuries or any other major complications. Real-time high-resolution fluorescent imaging to identify the biliary tree anatomy during SSRC using the da Vinci Fluorescence Imaging Vision System was safe and effective.