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Matching the LenStar optical biometer to A-Scan ultrasonography for use in small animal eyes with application to tree shrews
摘要： We describe an analysis strategy to obtain ultrasonography-matched axial dimensions of small animal eyes using the LenStar biometer. The LenStar optical low-coherence reflectometer is an attractive device for animal research due to its high precision, non-invasiveness, and the ability to measure the axial dimensions of cornea, anterior chamber, lens, vitreous chamber, and axial length. However, this optical biometer was designed for clinical applications in human eyes and its internal analysis provides inaccurate values when used on small eyes due to species-dependent differences in refractive indices and relative axial dimensions. The LenStar uses a near infrared light source to measure optical path lengths (OPLs) that are converted by the LenStar’s EyeSuite software into geometrical lengths (GLs) based on the refractive indices and axial dimensions of the human eye. We present a strategy that extracts the OPLs, determines refractive indices specific for the small animal eye of interest and then calculates corrected GLs. The refractive indices are obtained by matching the converted LenStar values to ultrasonography values in the same eyes. Using LenStar and ultrasonography measures of tree shrew eyes, we found that, compared to ultrasonography, the internal calculations of the LenStar underestimate the axial dimensions of all ocular compartments of the tree shrew eye: anterior segment depth by 6.17 ± 4.50%, lens thickness by 1.37 ± 3.06%, vitreous chamber depth by 29.23 ± 2.35%, and axial length by 10.62 ± 1.75%. Using tree-shrew specific refractive indices, the ocular compartment values closely matched the ultrasonography measures. Our analysis strategy can be easily translated to other species by obtaining a similar paired data set using ultrasonography and LenStar, and applying our step by step procedures.
关键词： LenStar,Ultrasonography,Tree Shrews,Ocular Axial Dimensions,Refractive Indices
更新于2025-09-23 15:23:52
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Comparison of immersion ultrasound and low coherence reflectometry for ocular biometry in cataract patients
摘要： ● Aim: To compare the results of axial length (AL) biometry in cataract eyes by three methods: immersion B-ultrasound (iB) biometry, immersion A-ultrasound (iA) biometry and optical low coherence reflectometry. ● Methods: In this prospective observational study of eyes with cataract AL measurements were performed using immersion ultrasound and optical low coherence reflectometry device. The results were evaluated using Bland-Altman analyses. The differences between both methods were assessed using the paired t-test, and its correlation was evaluated by Pearson coefficient. ● Results: Eighty eyes of 80 patients (39 men and 41 women) for cataract surgery were included in the study. The values of AL could be got from all 80 eyes by iB and iA, the difference of AL measurements between iA and iB was of no statistical significance (P=0.97); the mean difference in AL measurements was -0.031 mm (P=0.26; 95%CI, -0.09 to 0.02); linear regression showed an excellent correlation (r=0.98, P<0.0001). Forty-five of eighty eyes with results of AL measurements, which can be obtained by three methods; the difference of AL measurements was of no statistical significance (iA vs iB, P=0.18; iA vs Lenstar, P=0.51; iB vs Lenstar, P=0.07); linear regression showed an excellent correlation (iA vs iB, r=0.99; iA vs Lenstar, r=0.96; iB vs Lenstar, r=0.96); Bland-Altman analysis also showed good agreement between the two methods [iA vs iB, 95% limits of agreement (LoA), -0.36 to 0.28 mm; iA vs Lenstar, 95% LoA, -0.65 to 0.69 mm; iB vs Lenstar, 95% LoA, -0.55 to 0.68 mm]. ● Conclusion: Measurements with the optical low coherence reflectometry correlated well with iB and iA.
关键词： ultrasonography,axial length,immersion,biometry
更新于2025-09-23 15:23:52
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Diagnostic imaging and radiation exposure in inflammatory bowel disease
摘要： Diagnostic imaging plays a key role in the diagnosis and management of inflammatory bowel disease (IBD). However due to the relapsing nature of IBD, there is growing concern that IBD patients may be exposed to potentially harmful cumulative levels of ionising radiation in their lifetime, increasing malignant potential in a population already at risk. In this review we explore the proportion of IBD patients exposed to high cumulative radiation doses, the risk factors associated with higher radiation exposures, and we compare conventional diagnostic imaging with newer radiation-free imaging techniques used in the evaluation of patients with IBD. While computed tomography (CT) performs well as an imaging modality for IBD, the effective radiation dose is considerably higher than other abdominal imaging modalities. It is increasingly recognised that CT imaging remains responsible for the majority of diagnostic medical radiation to which IBD patients are exposed. Magnetic resonance imaging (MRI) and small intestine contrast enhanced ultrasonography (SICUS) have now emerged as suitable radiation-free alternatives to CT imaging, with comparable diagnostic accuracy. The routine use of MRI and SICUS for the clinical evaluation of patients with known or suspected small bowel Crohn’s disease is to be encouraged wherever possible. More provision is needed for out-of-hours radiation-free imaging modalities to reduce the need for CT.
关键词： Diagnostic medical radiation,Small intestine contrast-enhanced ultrasonography,Nuclear medicine,Computerised tomography,Inflammatory bowel disease,Magnetic resonance enterography,Small bowel follow-through
更新于2025-09-23 15:22:29
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Staging laparoscopy with ultrasound and near-infrared fluorescence imaging to detect occult metastases of pancreatic and periampullary cancer
摘要： Introduction Up to 38% of pancreatic and periampullary cancer patients undergoing curative intended surgery turn out to have incurable disease. Therefore, staging laparoscopy (SL) prior to laparotomy is advised to spare patients the morbidity, inconvenience and expense of futile major surgery. The aim of this study was to assess the added value of SL with laparoscopic ultrasonography (LUS) and laparoscopic near-infrared fluorescence imaging (LFI). Methods All patients undergoing curative intended surgery of pancreatic or periampullary cancer were included prospectively in this single arm study. Patients received an intravenous infusion of 10 mg indocyanine green (ICG) one or two days prior to surgery to allow LFI. Suspect lesions were analyzed via biopsy or resection. Follow-up visits after surgery occurred every three months. Results A total of 25 patients were included. Suspect lesions were identified in 7 patients: liver metastases (n = 2; identified by inspection, LUS, and LFI), peritoneal metastases (n = 1; identified by inspection only), and benign lesions (n = 4; identified by inspection or LUS). Quality of LFI was good in 67% (10/15) of patients dosed one day and 89% (8/9) dosed two days prior to surgery. A futile laparotomy was averted in 3 patients (12%). Following SL the primary tumor was resected in 20 patients. Two patients (10%) developed metastases within 3 months after resection. Conclusions Despite current preoperative imaging modalities metastases are still identified during surgery. This study shows limited added value of LUS during SL in patients with pancreatic or periampullary cancer. LFI was of added value due to its high negative predictive value in case of suspect hepatic lesions identified by inspection.
关键词： near-infrared fluorescence imaging,staging laparoscopy,laparoscopic ultrasonography,pancreatic cancer,periampullary cancer,indocyanine green
更新于2025-09-23 15:21:01
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Automated diagnosis of breast ultrasonography images using deep neural networks
摘要： Ultrasonography images of breast mass aid in the detection and diagnosis of breast cancer. Manually analyzing ultrasonography images is time-consuming, exhausting and subjective. Automated analyzing such images is desired. In this study, we develop an automated breast cancer diagnosis model for ultra-sonography images. Traditional methods of automated ultrasonography images analysis employ hand-crafted features to classify images, and lack robustness to the variation in the shapes, size and texture of breast lesions, leading to low sensitivity in clinical applications. To overcome these shortcomings, we propose a method to diagnose breast ultrasonography images using deep convolutional neural networks with multi-scale kernels and skip connections. Our method consists of two components: the first one is to determine whether there are ma-lignant tumors in the image, and the second one is to recognize solid nodules. In order to let the two networks work in a collaborative way, a region enhance mechanism based on class activation maps is proposed. The mechanism helps to improve classification accuracy and sensitivity for both networks. A cross training algorithm is introduced to train the networks. We construct a large annotated dataset containing a total of 8145 breast ultrasonography images to train and evaluate the models. All of the annotations are proven by patho-logical records. The proposed method is compared with two state-of-the-art approaches, and outperforms both of them by a large margin. Experimental results show that our approach achieves a performance comparable to human sonographers and can be applied to clinical scenarios.
关键词： ultrasonography,breast cancer,deep neural networks
更新于2025-09-23 15:19:57
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Computing uveal melanoma basal diameters: a comparative analysis of several novel techniques with improved accuracy
摘要： Background: We sought to compare the accuracy of standard and novel echographic methods for computing intraocular tumor largest basal diameter (LBD). Design: Multicenter, retrospective cohort study. Subjects: All patients presenting with new diagnosis of uveal melanoma (UM). Methods: Ultrasounds were obtained for all patients, and axial length (AL) was measured for a subset of patients. LBD was calculated as: (1) a single chord measured on B scan ultrasound (one-chord method [1CM]), or (2) by subdividing the basal diameter into two chords, which were summated (two-chord method [2CM]), or (3) by a mathematically-derived formula (MF) based on geometric relationships. The accuracy of each method was then compared, and sensitivity of each technique to factors such as tumor size and AL were analyzed. Main outcome measures: Accuracy, robustness, correctness of predicted plaque size. Results: 116 UMs were analyzed; 1CM-calculated LBD underestimated 2CM-calculated LBD by 7.5% and underestimated LBD by MF by 7.8%; 2CM and MF were tightly correlated (average LBD difference 0.038%). At larger LBDs, 1CM underestimated 2CM and MF by a much greater percentage (p < 0.001). By linear regression, 1CM underestimated LBD compared to 2CM by 0.8% and underestimated LBD compared to MF by 1.2% for every 1-mm LBD increase (p < 0.001 for each). Increasing the number of ultrasound chords beyond two did not significantly impact LBD calculations. For eyes with AL within two standard deviations of the mean, AL did not impact plaque selection using MF. 1CM would have led to selection of an undersized plaque in 41% of cases compared to 2CM and would have misclassified half of all eyes that actually required enucleation. For tumors with LBD < 12 mm, 1CM does not significantly underestimate LBD. Conclusions: Tumor LBD by 1CM is an inaccurate means of determining actual LBD, especially for larger tumors. Using either 2CM or MF is much more accurate, especially for tumors > 12 mm, where a single chord on ultrasound is more likely to lead to incorrect, undersized plaque selection. Our MF can be applied with great accuracy even in cases where the AL of the eye is not measured, using the population average AL (23.7 mm), and the formula LBD = 23.7 sin?1(chord length/23.7).
关键词： Ultrasonography,Plaque brachytherapy,Uveal melanoma,Ocular tumors
更新于2025-09-19 17:15:36
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[IEEE TENCON 2019 - 2019 IEEE Region 10 Conference (TENCON) - Kochi, India (2019.10.17-2019.10.20)] TENCON 2019 - 2019 IEEE Region 10 Conference (TENCON) - Point-of-care functional and molecular imaging using LED-based photoacoustics
摘要： Photoacoustic (PA) or optoacoustic imaging can visualize tissue-optical absorbers, especially hemoglobin, with optical contrast and ultrasound (US)-like resolution and imaging depth. Since both PA and US imaging involves US detection, it is straightforward to develop dual-mode imaging systems with unprecedented functional and structural imaging capabilities. Researchers have already demonstrated the potential of utilizing this complementary contrast imaging for several animal imaging experiments and early clinical pilot studies. PA conventionally uses slow, bulky and high-priced lasers as excitation sources. Use of these high-power pulsed lasers is hindering the clinical translation process of this imaging modality with tremendous potential. Advances in solid-state device technology have recently resulted in the development of a new class of high-power light emitting diodes (LEDs) that can be used as fast, robust and affordable pulsed excitation sources for PA imaging. In this paper, we review multiple LED-based PA/US imaging implementations (commercial and lab-made systems) and demonstrate its functional, molecular and structural imaging capabilities using several clinical/preclinical imaging examples. Specific focus will be given to 2D and 3D superficial vasculature and oxygen saturation imaging in multiple in vivo clinical and preclinical studies.
关键词： ultrasonography,vasculature,photoacoustic imaging,oxygenation imaging,LED
更新于2025-09-16 10:30:52
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Assessment of Vitreous Structure and Visual Function after Neodymium:Yttrium–Aluminum–Garnet Laser Vitreolysis
摘要： Purpose: Neodymium:yttriumealuminumegarnet (Nd:YAG) laser treatment is performed on vitreous ?oaters, but studies of structural and functional effects with objective outcome measures are lacking. This study evaluated Nd:YAG laser effects by comparing participants with vitreous ?oaters who previously underwent laser treatment with untreated control participants and healthy persons without vitreous ?oaters using quantitative ultrasonography to evaluate vitreous structure and by measuring visual acuity and contrast sensitivity function to assess vision. Design: Retrospective, comparative study. Participants: One eye was enrolled for each of 132 participants: 35 control participants without vitreous ?oaters, 59 participants with untreated vitreous ?oaters, and 38 participants with vitreous ?oaters previously Nd:YAG-treated. Of these, 25 were dissatis?ed and sought vitrectomy; 13 were satis?ed with observation. Methods: The 39-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-39) to assess participant visual well-being, quantitative ultrasonography (QUS) to measure vitreous echodensity, and best-corrected visual acuity (BCVA) and contrast sensitivity function (CSF) to evaluate vision. Main Outcome Measures: Results of NEI-VFQ-39, QUS, BCVA, and CSF. Results: Compared with control participants without vitreous ?oaters, participants with untreated vitreous ?oaters showed worse NEI-VFQ-39 results, 57% greater vitreous echodensity, and signi?cant (130%) CSF degradation (P < 0.001 for each). Compared with untreated eyes with vitreous ?oaters, Nd:YAG-treated eyes had 23% less vitreous echodensity (P < 0.001), but no differences in NEI-VFQ-39 (P ? 0.51), BCVA (P ? 0.42), and CSF (P ? 0.17) results. Of 38 participants with vitreous ?oaters who previously were treated with Nd:YAG, 25 were dissatis?ed and seeking vitrectomy, whereas 13 were satis?ed with observation. Participants seeking vitrectomy showed 24% greater vitreous echodensity (P ? 0.018) and 52% worse CSF (P ? 0.006). Multivariate linear regression models con?rmed these ?ndings. Conclusions: As a group, participants previously treated with Nd:YAG laser for bothersome vitreous ?oaters showed less dense vitreous, but similar visual function as untreated control participants with vitreous ?oaters. Because some treated eyes showed less dense vitreous and better visual function than those of untreated control participants, a prospective randomized study of Nd:YAG laser treatment of vitreous is warranted, using uniform laser treatment parameters and objective quantitative outcome measures.
关键词： Neodymium:yttriumealuminumegarnet (Nd:YAG) laser,vitreous ?oaters,best-corrected visual acuity,quantitative ultrasonography,contrast sensitivity function
更新于2025-09-12 10:27:22
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Diode Laser Photocoagulation of Intraoral and Perioral Venous Malformations After Tridimensional Staging by High Definition Ultrasonography
摘要： Objective: To determine optimal settings for use of diode lasers to treat vascular malformations in the head and neck. Background: Diode lasers are generally accepted as effective tools to treat vascular malformations in the head and neck, yet there are no standardized treatment protocols for this treatment approach. Settings for these lasers, in addition to laser type and size and lesion depth are important variables for designing appropriate treatments for vascular malformations. Materials and methods: Vascular venous malformations (VeMs) were classi?ed into ?ve groups according to high-de?nition ultrasound measurements of super?cial dimensions (<1, 1–3, and >3 cm) and lesion extension depth (￡5, and >5 mm). Using a 800 – 10 nm diode laser for surgical procedures, we treated lesions by two different approaches: trans-mucous/cutaneous photocoagulation (8 and 12 W pulsed wave for cutaneous and mucosal lesions, respectively) and intralesional photocoagulation using a laser set to 13 W in the pulsed wave modality to treat both cutaneous and mucosal lesions. Results: We treated 158 vascular VeMs. According to preoperative staging, there were 52 lesions in Group A (super?cial dimension <1 cm), 28 in Group B1 (super?cial dimension from 1 to 3 cm, extension depth ￡5 mm), 16 in Group B2 (super?cial dimension from 1 to 3 cm, extension depth >5 mm), 42 in Group C1 (super?cial dimension >3 cm, extension depth ￡5 mm), and 12 in Group C2 (super?cial dimension >3 cm, extension depth >5 mm). All Group A lesions showed complete healing after a single laser treatment, whereas 7%, 10%, 12%, and 16% of lesions classi?ed in Groups B1, B2, C1, and C2, respectively, required further treatments. Conclusions: The laser settings de?ned in this study were associated with a reduced number of laser applications needed for effective treatment of vascular VeMs. Moreover, the cooling of irradiated tissues, together with prolonged application of a topical regenerative gel, provided good treatment acceptability, reduced the number of postoperative complications, and promoted faster healing of covering tissues.
关键词： diode laser,ultrasonography,vascular venous malformations,photocoagulation
更新于2025-09-12 10:27:22
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Blood Flow in Monocular Retinoblastoma Assessed by Color Doppler and Correlations With High-Risk Pathologic Features
摘要： PURPOSE. To use color Doppler to analyze blood ?ow in the retrobulbar central retinal artery (CRA) and central retinal vein (CRV) in monocular retinoblastoma. METHODS. This prospective study included patients with group D and E retinoblastomas managed with only enucleation. Peak blood velocities were assessed in the CRA and CRV of tumor-containing eyes (CRAv and CRVv, respectively). The resistivity index in the CRA (RIa) and pulse index in the CRV (PIv) were calculated and related to optic nerve invasion (ONi), choroid invasion (mCHi), and tumor volume. RIa and PIv were also calculated for healthy eyes. RESULTS. In total, 25 patients with a mean age of 30.8-months old were included. The means (SD) for CRAv, CRVv, RIa, and PIv were 26.94 (12.32) cm/s, 16.2 (9.56) cm/s, 0.88 (0.12) and 0.79 (0.29), respectively. Tumor volume was signi?cantly correlated with CRAv (P ? 0.025) and RIa (P ? 0.032). ONi was present in 19 eyes and correlated with a smaller PIv (P < 0.001). A PIv less than 0.935 had a sensitivity of 89.5% and speci?city of 83.3% for predicting ONi. mCHi was not correlated with ?ow values. Healthy eyes had a signi?cantly lower RIa (P < 0.001) and lower PIv than eyes with (P ? 0.009) and without (P < 0.001) ONi. tumor volume was directly CONCLUSIONS. correlated with CRAv and RIa, and lower PIv was correlated with optic nerve invasion when a predictive cut-off value of less than 0.935 was applied. Comparisons with healthy eyes showed that tumor-containing eyes were associated with higher RIa and PIv values.
关键词： histopathology,eye enucleation,blood flow velocity,retinoblastoma,color doppler ultrasonography
更新于2025-09-09 09:28:46