Cutaneous neurofibromas (cNFs) occur in individuals with germline neurofibromatosis type I pathogenic variants. Current management involves monitoring and limited surgical removal. Nascent cNFs are lesions detectable only through advanced imaging and not observable with the unaided eye. Noninvasive early detection may enable intervention before cNF become visible. We introduce an imaging approach integrating spatial frequency domain imaging and high-frequency ultrasound to identify and characterize suspected nascent cNFs. In 21 participants with neurofibromatosis type I, we identified 152 suspected nascent lesions using spatial frequency domain imaging as skin regions with decreased optical scattering at near-infrared wavelengths. Of these, 120 were imaged with high-frequency ultrasound, and 93% demonstrated subsurface hypoechoic dermal structures. Paired analyses of the reduced scattering coefficient (μs') at 851 nm showed that μs' within suspected nascent cNFs was significantly lower than that of adjacent uninvolved skin, supporting μs' as a candidate imaging feature for nascent cNFs. Statistical variation in overlying dermal thickness and lesion dimensions is summarized. Integrating spatial frequency domain imaging and high-frequency ultrasound represents a multimodal approach for imaging characterization of suspected nascent cNFs and may advance the understanding of cNF progression and the development of treatment strategies. This feasibility study does not establish nascent cNF diagnostic detection accuracy because histologic confirmation was limited.
Prior laser studies have demonstrated that as the temperature of a medium increases, the amount of energy delivered to the target increases. We sought to investigate the role of irrigation fluid temperature on Thulium fiber laser (TFL) urolith ablation. 360 calculi were divided in vitro according to chemical composition: calcium oxalate monohydrate (COM), cystine (CYS), struvite (STR), calcium phosphate (CAP), uric acid (UA), and calcium oxalate dihydrate (COD). A 200 μm TFL was placed directly on each stone, while immersed in 0.9
Introduction: Laser dosimetry selection is utilized to reduce stone retropulsion. Diode-pumped thulium fiber lasers (TFLs) allow for increased pulse energy by lengthening the pulse width. As pulse width lengthens, thermal diffusion has the potential to increase temperature generation outside of an irradiated target. We test the hypothesis that extending the TFL pulse duration longer than the thermal relaxation time poses an independent risk for increased nonspecific heat generation. Methods: A two-dimensional numerical simulation of TFL thermal confinement was performed. Energy output and pulse duration of the SOLTIVE Premium-SuperPulsed TFL were measured. Pulse energies (1.5 J) were selected for pulse durations shorter and longer than thermal relaxation time. Temperature was measured by thermocouple positioned 1 cm lateral to the fiber tip. We compared temperature increases in vitro for identical dosimetries (1.5 J at 20 Hz for 300 seconds) for short (3.1 ms) vs long (11.8 ms) pulse durations. Results: TFL thermal confinement time was calculated at 11.4 ms. For any given preset (short or long), pulse width (duration) increased as pulse energy increased. For any given pulse energy, pulse duration was 3 to 4 times longer comparing short vs long presets. For both short and long pulse settings, temperature increased as total energy increased. The maximum temperature achieved for the long pulse width was 79.6°C vs 71.8°C for the short-width arm (p = 0.002). Conclusion: TFL pulse duration longer than the thermal relaxation time poses an independent risk for increased nonspecific heat generation.
Background:Intravascular optical coherence tomography (IVOCT) adoption has been limited by the complexity of image interpretation. The interpretation of histologic subtypes beyond lipid, calcium, and fibrous is challenging to human readers. To assist and standardize IVOCT image analysis, we demonstrate an artificial intelligence algorithm based on a histology data set that identifies lipid pools, fibrofatty, calcified lipid, and calcified fibrous in human coronary arteries for the first time. Methods:Sixty-seven human coronary arteries were imaged with IVOCT within 24 hours after death and then underwent histologic examination. IVOCT images were coregistered and segmented into histologic subtypes: lipid pools, fibrofatty tissue, calcified lipid, and calcified fibrous tissue. Experiments regarding lipidic plaque included fibrofatty tissue, lipid pools, and calcified lipids. Experiments regarding calcium plaque included calcified fibrous and calcified lipid plaques. Optical coherence tomography images were lumen justified and cropped to a depth of 200 pixels (1 mm) to account for limited optical coherence tomography penetration depth. IVOCT segmentations from expert readers guided by histology were used to train segmentation neural networks. Results:For each data set, in addition to testing each of these subtypes individually, we trained and tested the model on the combined grouping of subtypes. Combined lipid subtypes achieved validation and test Dice (Sørensen-Dice coefficient) of 0.63 and 0.40, respectively, whereas combined calcium subtypes achieved validation and test Dice of 0.66 and 0.62, respectively. Conclusions:This histology-validated artificial intelligence algorithm driven by histologic subtypes can identify plaque subtypes not evident to a human reader. The reported algorithm can provide a fast solution to IVOCT image interpretation.
Introduction: This study addresses pulse modulation for kidney stone lithotripsy using diode-pumped thulium yttrium aluminum garnet (Tm:YAG, λ = 2.02 µm) and thulium fiber lasers (TFLs, λ = 1.94 µm). Three research questions were investigated: (1) What are the effects of varying pulse duration and energy of the first pulse and varying the interpulse delay in a pulse modulation sequence to increase energy transfer across saline to a stone? (2) Does an optimal pulse modulation profile exist in a single-pulse sequence to provide highest percent radiant energy transfer? (3) Does a higher effective energy transfer to the stone using pulse modulation produce greater stone volumetric removal? Materials and Methods: We measured radiant energy transmission efficiency (RETE) and ablation volumes in phantom and human stones. RETE was utilized to compare the pulse energy transmission through air and saline media. We recorded fast camera traces and vapor bubble collapse pressures. Craters were created at fiber standoff distances (SDs) of 0.0 mm, 0.5 mm, and 1.0 mm, and volumes were measured using optical coherence tomography. Results: For Tm:YAG laser irradiation, dual-pulse mode significantly increased RETE by as much as 75% at 1 mm SD compared with single-pulse mode. With the Tm:YAG laser, an optimal "dual-pulse" modulation resulted in greater volumetric removal compared with a "single-pulse" across all stone cohorts (p < 0.05) except for calcium oxalate monohydrate stones (p = 0.38) at a 1 mm SD. TFL yielded similar results, but showed heterogeneity across stone compositions. Conclusions: Pulse-modulated diode-pumped Tm:YAG and TFL can deliver higher photon count through a saline layer if the first pulse is optimized. An optimal pulse modulation profile where the second pulse is synchronized with the vapor bubble dynamics of the first pulse results in the highest percent RETE and increased stone volumetric removal.
Cutaneous neurofibromas (cNF) appear commonly in neurofibromatosis type I (NF1) patients. cNFs usually appear in the skin at puberty and proliferate with increasing numbers and sizes throughout life. If cNFs can be detected and treated in their nascent stage, patient's quality of life can be improved. To detect early-stage cNF, we have employed spatial frequency domain imaging (SFDI) and optical coherence tomography (OCT). SFDI has been applied to screen large skin areas on eleven cNF subjects. Suspect lesions invisible to the unaided eye but detected using SFDI were imaged with OCT to observe lesion microstructure. Three lesions were biopsied to compare with SFDI and OCT images. Suspect nascent cNFs which are invisible to the unaided eye were detected as low optical scattering regions in all patients. Large area screening using SFDI confirmed scattering contrast between the suspect nascent cNF and the surrounding uninvolved skin. Abnormal disc-shaped structures with reduced scattering regions detected by SFDI were also observed in OCT cross-sections.
You have accessJournal of UrologyStone Disease: Basic Research & Pathophysiology (MP63)1 May 2024MP63-01 THE IMPACT OF IRRIGATION FLUID TEMPERATURE ON SUPERPULSE THULIUM FIBER LASER STONE ABLATION Andrei Dragos Cumpanas, Nitesh Katta, Yi Xi Wu, Antonio R. H. Gorgen, Jacob C. Tsai, Thao N. Vu, Mariah C. Hernandez, Kelvin Vo, Jaime Altamirano Villaroel, Bruce Gao, Zachary E. Tano, Pengbo Jiang, Roshan M. Patel, Thomas Milner, Jaime Landman, and Ralph V. Clayman Andrei Dragos CumpanasAndrei Dragos Cumpanas , Nitesh KattaNitesh Katta , Yi Xi WuYi Xi Wu , Antonio R. H. GorgenAntonio R. H. Gorgen , Jacob C. TsaiJacob C. Tsai , Thao N. VuThao N. Vu , Mariah C. HernandezMariah C. Hernandez , Kelvin VoKelvin Vo , Jaime Altamirano VillaroelJaime Altamirano Villaroel , Bruce GaoBruce Gao , Zachary E. TanoZachary E. Tano , Pengbo JiangPengbo Jiang , Roshan M. PatelRoshan M. Patel , Thomas MilnerThomas Milner , Jaime LandmanJaime Landman , and Ralph V. ClaymanRalph V. Clayman View All Author Informationhttps://doi.org/10.1097/01.JU.0001009436.52988.91.01AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Laser physics has demonstrated that as the temperature of a medium rises, the amount of energy delivered to the target increases. We hypothesized that this effect could possibly enhance laser lithotripsy. Accordingly, we evaluated the effect of increased irrigation fluid temperature on the degree of stone ablation during superpulse Thulium fiber laser (sTFL) lithotripsy among 360 urolithis of six different compositions. METHODS: 360 human uroliths were divided based on their chemical composition: calcium oxalate monohydrate (COM), cystine (CYS), struvite (STR), calcium phosphate (CP), uric acid (UA), and calcium oxalate dihydrate (COD). With the tip of a 200 µm sTFL fiber in contact with each stone, while immersed in 0.9% NaCl, at four different temperatures (25°C, 37°C,44°C, and 60°C) a single laser pulse was delivered at 0.1 J, 0.5 J, or 1.5 J. Optical coherence tomography was applied to assess the volume of the single-pulse ablation cone. The difference in mean ablation cone volume was assessed by ANOVA testing and Tukey post-hoc analysis. A multivariate generalized model was developed for each stone type to account for the impact of fluid temperature and laser energy on stone ablation. RESULTS: Warmer fluid temperatures yielded greater ablation cone volumes for most energy settings and for all non-UA stones (Figure 1). When accounting for individual chemical compositions, stones with more tensile strength and a higher thermal threshold (i.e., COM and CYS) benefited the most from increasing the temperature of the irrigation fluid. More frangible stones (i.e., CP and STR) were only mildly affected by temperature. Of note, the effect of increasing fluid temperature is modest in comparison to the impact of increasing laser pulse energy; a large increase (i.e. 7°C) in fluid temperature is equivalent to a minor (i.e., 0.1J) increase in delivered energy (Table 1). CONCLUSIONS: For non-UA stones, sTFL stone ablation efficiency increases with warmer irrigation fluid. The effect, albeit modest in comparison to laser pulse energy, was most notable for COM and CYS stones. Download PPT Source of Funding: None © 2024 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 211Issue 5SMay 2024Page: e1030 Advertisement Copyright & Permissions© 2024 by American Urological Association Education and Research, Inc.Metrics Author Information Andrei Dragos Cumpanas More articles by this author Nitesh Katta More articles by this author Yi Xi Wu More articles by this author Antonio R. H. Gorgen More articles by this author Jacob C. Tsai More articles by this author Thao N. Vu More articles by this author Mariah C. Hernandez More articles by this author Kelvin Vo More articles by this author Jaime Altamirano Villaroel More articles by this author Bruce Gao More articles by this author Zachary E. Tano More articles by this author Pengbo Jiang More articles by this author Roshan M. Patel More articles by this author Thomas Milner More articles by this author Jaime Landman More articles by this author Ralph V. Clayman More articles by this author Expand All Advertisement PDF downloadLoading ...
You have accessJournal of UrologySurgical Technology & Simulation: Instrumentation & Technology II (MP43)1 May 2024MP43-12 EFFECT OF PULSE MODULATION ON STONE ABLATION USING A DIODE-PUMPED TM:YAG LASER Nitesh Katta, Katherine Lydia Sikorski, Joel Teichman, and Thomas E. Milner Nitesh KattaNitesh Katta , Katherine Lydia SikorskiKatherine Lydia Sikorski , Joel TeichmanJoel Teichman , and Thomas E. MilnerThomas E. Milner View All Author Informationhttps://doi.org/10.1097/01.JU.0001008720.96896.83.12AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: We studied how pulse characteristics affect stone ablation, seeking to find the optimal pulse modulation with a diode-pumped thulium yttrium aluminum garnet (Tm:YAG) laser. We also examined the impact of effective energy transmission (EET) from the fiber tip to the stone through optimal pulse modulation at various stand-off distances (SD). METHODS: We used a diode-pumped Tm:YAG laser (2060 nm, 1500 W) with adjustable pulse parameters, in single- and dual-pulse modes to assess EET from the fiber tip to stone target through water at varying stand-off distances (SD). EET was calculated for each experiment using EET=100*(REwater/REair) %, where REsaline is the measured pulse radiant energy through water versus REair is the measured pulse radiant energy in air. We tested single and dual-pulse ablation with gypsum stones and natural human kidney stones including calcium oxalate monohydrate (COM), uric acid (UA), calcium oxalate dihydrate (COD), calcium phosphate (CaPO4). Post-ablation, optical coherence tomography was used to image craters and calculate ablation volume. Student's t-test was used for statistical analysis. RESULTS: Dual-pulse modulation using diode-pumped Tm:YAG provided higher EET compared to single pulses at SD>0.5 mm, corresponding to more photons reaching the stone (Figure 1A). Dual-pulse mode consistently showed greater gypsum phantom stone crater ablation volume at SD=0.5 mm (p<0.001) and and SD=1 mm (p<0.001), and for hardened gypsum (p<0.004) and for Ultracal30 (p<0.003). For native stones, dual-pulse outperformed single pulse mode in crater volume across most cohorts. In COM, the difference in crater volume was not statistically significant (p=0.4), but was significant for UA (p=0.02), CaPO4 (p=0.04), and COD (p=0.03) at SD=1 mm (Figure 1B), and COM (p<0.01), UA (p<0.05), CaPO4 (p<0.008), and COD (p<0.004) at SD=0.5 mm. CONCLUSIONS: Effective energy transmission is essential for photothermal stone removal. Experimental results support that photothermal effects dominate stone removal mechanism of action across all compositions and conditions with diode-pumped lasers. Pulse pause duration affects fragmentation. Pulse modulation can enhance ablation volumes per unit radiant energy in phantom stones but can vary with stone composition. Download PPT Source of Funding: University of California at Irvine (UCI) school of medicine start-up funds to Thomas E. Milner © 2024 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 211Issue 5SMay 2024Page: e698 Advertisement Copyright & Permissions© 2024 by American Urological Association Education and Research, Inc.Metrics Author Information Nitesh Katta More articles by this author Katherine Lydia Sikorski More articles by this author Joel Teichman More articles by this author Thomas E. Milner More articles by this author Expand All Advertisement PDF downloadLoading ...
This review examines circadian dysregulation and the role of Müller glial cells (MGCs) in retinal degeneration associated with Alzheimer’s disease (AD). Evidence supporting the interdependence of circadian rhythm (CR) disruption and AD progression is presented. Also reviweed are reports substantiating the role of MGCs in maintaining CR. Studies documenting MGC dysfunction in AD retinas suggest that gliosis, altered diurnal patterns in water homeostasis, blood-retina barrier breakdown, and impaired ocular glymphatic clearance are relevant to disease progression. Similarities between AD and various retinopathies are explored with respect to MGC physiology and CR dysfunction. We propose that MGC circadian dysregulation is diagnostically and therapeutically relevant to AD retinopathy.
Recent studies suggest that cavitation effect following laser induced vapor bubble collapse is more dominant than the photothermal effect in stone ablation during laser lithotripsy. Our research aims to introduce an experimental study design that precisely measures each effect's contribution using gypsum phantom stones. To isolate the cavitation-only mechanism after the collapse of the laser-induced vapor bubble, a phantom stone was submerged in a dye solution. The dye solution absorbed all laser light, generating cavitation, with additional experiments confirming the absence of any photothermal effect when the dye was not used. The fiber was positioned both parallel to the stone surface and perpendicular at a 1mm distance, exposing it solely to cavitation. In another set of experiments, a phantom stone was submerged in water and 2μm light from a thulium yttrium aluminum garnet (Tm:YAG) laser was delivered via the same optical fiber positioned (this time) perpendicular to the stone surface. In this case, both optical absorption and cavitation effect from laser-induced vapor bubble collapses were observed but the measured pressure transients showed significantly lower peak pressures compared to the first set. In a final set of experiments, these conditions remained constant, except the fiber was positioned parallel to the stone surface, once again exposing it to only the cavitation from the collapse of the laser induced vapor bubble. Craters created by all methods were imaged using an optical coherence tomography (OCT) system. Measured volumes showed that stone ablation was dominated by photo-thermal, and not by cavitation from the vapor bubble collapse. In fact, in two of the three trials of stone experiments (n=5, each trial) that were subjected to cavitation-only, there was no observable ablation. One trial produced an average volume that was 50% smaller than the average resulting from a single photo-thermal-only case (p = 0.0022 < 0.05). Our results suggest that finetuning of lithotripsy procedures with focus on energy transmission to the stone can provide optimal results.
A consistent set of measurement techniques must be applied to reliably and reproducibly evaluate the efficacy of treatments for cutaneous neurofibromas (cNFs) in people with neurofibromatosis type 1 (NF1). cNFs are neurocutaneous tumors that are the most common tumor in people with NF1 and represent an area of unmet clinical need. This review presents the available data regarding approaches in use or development to identify, measure, and track cNFs, including calipers, digital imaging, and high-frequency ultrasound sonography. We also describe emerging technologies such as spatial frequency domain imaging and the application of imaging modalities such as optical coherence tomography that may enable the detection of early cNFs and prevention of tumor-associated morbidity.
Management of intracoronary calcium (ICC) continues to be a challenge for interventional cardiologists. There have been significant advances in calcium treatment devices. However, there still exists a knowledge gap regarding which devices to choose for the treatment of ICC. The purpose of this manuscript is to review the principles of intravascular lithotripsy (IVL) and clinical data. The technique of IVL will then be compared to alternative calcium treatment devices. Clinical data will be reviewed concerning the treatment of coronary, peripheral artery and valvular calcifications. Controversies to be discussed include how to incorporate IVL into your practice, what is the best approach for treating calcium subtypes, how to approach under-expanded stents, what is the ideal technique for performing IVL, how safe is IVL, whether imaging adds value when performing IVL, and how IVL fits into a treatment program for peripheral arteries and calcified valves.
