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1.
BJU Int ; 2024 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-38989669

RESUMEN

OBJECTIVES: To externally validate the performance of the DeepDx Prostate artificial intelligence (AI) algorithm (Deep Bio Inc., Seoul, South Korea) for Gleason grading on whole-mount prostate histopathology, considering potential variations observed when applying AI models trained on biopsy samples to radical prostatectomy (RP) specimens due to inherent differences in tissue representation and sample size. MATERIALS AND METHODS: The commercially available DeepDx Prostate AI algorithm is an automated Gleason grading system that was previously trained using 1133 prostate core biopsy images and validated on 700 biopsy images from two institutions. We assessed the AI algorithm's performance, which outputs Gleason patterns (3, 4, or 5), on 500 1-mm2 tiles created from 150 whole-mount RP specimens from a third institution. These patterns were then grouped into grade groups (GGs) for comparison with expert pathologist assessments. The reference standard was the International Society of Urological Pathology GG as established by two experienced uropathologists with a third expert to adjudicate discordant cases. We defined the main metric as the agreement with the reference standard, using Cohen's kappa. RESULTS: The agreement between the two experienced pathologists in determining GGs at the tile level had a quadratically weighted Cohen's kappa of 0.94. The agreement between the AI algorithm and the reference standard in differentiating cancerous vs non-cancerous tissue had an unweighted Cohen's kappa of 0.91. Additionally, the AI algorithm's agreement with the reference standard in classifying tiles into GGs had a quadratically weighted Cohen's kappa of 0.89. In distinguishing cancerous vs non-cancerous tissue, the AI algorithm achieved a sensitivity of 0.997 and specificity of 0.88; in classifying GG ≥2 vs GG 1 and non-cancerous tissue, it demonstrated a sensitivity of 0.98 and specificity of 0.85. CONCLUSION: The DeepDx Prostate AI algorithm had excellent agreement with expert uropathologists and performance in cancer identification and grading on RP specimens, despite being trained on biopsy specimens from an entirely different patient population.

2.
Nat Commun ; 15(1): 5116, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38879581

RESUMEN

Exposure to ambient air pollution has significant adverse health effects; however, whether air pollution is associated with urological cancer is largely unknown. We conduct a systematic review and meta-analysis with epidemiological studies, showing that a 5 µg/m3 increase in PM2.5 exposure is associated with a 6%, 7%, and 9%, increased risk of overall urological, bladder, and kidney cancer, respectively; and a 10 µg/m3 increase in NO2 is linked to a 3%, 4%, and 4% higher risk of overall urological, bladder, and prostate cancer, respectively. Were these associations to reflect causal relationships, lowering PM2.5 levels to 5.8 µg/m3 could reduce the age-standardized rate of urological cancer by 1.5 ~ 27/100,000 across the 15 countries with the highest PM2.5 level from the top 30 countries with the highest urological cancer burden. Implementing global health policies that can improve air quality could potentially reduce the risk of urologic cancer and alleviate its burden.


Asunto(s)
Contaminación del Aire , Material Particulado , Neoplasias Urológicas , Humanos , Contaminación del Aire/efectos adversos , Contaminación del Aire/análisis , Neoplasias Urológicas/epidemiología , Neoplasias Urológicas/etiología , Material Particulado/efectos adversos , Material Particulado/análisis , Masculino , Contaminantes Atmosféricos/efectos adversos , Contaminantes Atmosféricos/análisis , Exposición a Riesgos Ambientales/efectos adversos , Factores de Riesgo , Neoplasias de la Vejiga Urinaria/epidemiología , Neoplasias de la Vejiga Urinaria/etiología , Neoplasias Renales/epidemiología , Neoplasias Renales/etiología , Neoplasias de la Próstata/epidemiología , Neoplasias de la Próstata/etiología , Femenino
3.
Cancer ; 129(20): 3309-3317, 2023 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-37287332

RESUMEN

BACKGROUND: Kidney cancer incidence demonstrates significant geographic variation suggesting a role for environmental risk factors. This study sought to evaluate associations between groundwater exposures and kidney cancer incidence. METHODS: The authors identified constituents from 18,506 public groundwater wells in all 58 California counties measured in 1996-2010, and obtained county-level kidney cancer incidence data from the California Cancer Registry for 2003-2017. The authors developed a water-wide association study (WWAS) platform using XWAS methodology. Three cohorts were created with 5 years of groundwater measurements and 5-year kidney cancer incidence data. The authors fit Poisson regression models in each cohort to estimate the association between county-level average constituent concentrations and kidney cancer, adjusting for known risk factors: sex, obesity, smoking prevalence, and socioeconomic status at the county level. RESULTS: Thirteen groundwater constituents met stringent WWAS criteria (a false discovery rate <0.10 in the first cohort, followed by p values <.05 in subsequent cohorts) and were associated with kidney cancer incidence. The seven constituents directly related to kidney cancer incidence (and corresponding standardized incidence ratios) were chlordane (1.06; 95% confidence interval [CI], 1.02-1.10), dieldrin (1.04; 95% CI, 1.01-1.07), 1,2-dichloropropane (1.04; 95% CI, 1.02-1.05), 2,4,5-TP (1.03; 95% CI, 1.01-1.05), glyphosate (1.02; 95% CI, 1.01-1.04), endothall (1.02; 95% CI, 1.01-1.03), and carbaryl (1.02; 95% CI, 1.01-1.03). Among the six constituents inversely related to kidney cancer incidence, the standardized incidence ratio furthest from the null was for bromide (0.97; 95% CI, 0.94-0.99). CONCLUSIONS: This study identified several groundwater constituents associated with kidney cancer. Public health efforts to reduce the burden of kidney cancer should consider groundwater constituents as environmental exposures that may be associated with the incidence of kidney cancer.


Asunto(s)
Carcinoma de Células Renales , Agua Subterránea , Neoplasias Renales , Humanos , Incidencia , Exposición a Riesgos Ambientales/efectos adversos , Neoplasias Renales/epidemiología
4.
Urol Clin North Am ; 50(2): 191-204, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-36948666

RESUMEN

Renal cell carcinoma (RCC) is a heterogeneous disease characterized by a broad spectrum of disorders in terms of genetics, molecular and clinical characteristics. There is an urgent need for noninvasive tools to stratify and select patients for treatment accurately. In this review, we analyze serum, urinary, and imaging biomarkers that have the potential to detect malignant tumors in patients with RCC. We discuss the characteristics of these numerous biomarkers and their ability to be used routinely in clinical practice. The development of biomarkers continues to evolve with promising prospects.


Asunto(s)
Carcinoma de Células Renales , Neoplasias Renales , Humanos , Carcinoma de Células Renales/diagnóstico , Carcinoma de Células Renales/patología , Biomarcadores de Tumor , Neoplasias Renales/diagnóstico , Neoplasias Renales/patología
5.
Eur Urol Focus ; 9(4): 584-591, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-36372735

RESUMEN

BACKGROUND: Tissue preservation strategies have been increasingly used for the management of localized prostate cancer. Focal ablation using ultrasound-guided high-intensity focused ultrasound (HIFU) has demonstrated promising short and medium-term oncological outcomes. Advancements in HIFU therapy such as the introduction of tissue change monitoring (TCM) aim to further improve treatment efficacy. OBJECTIVE: To evaluate the association between intraoperative TCM during HIFU focal therapy for localized prostate cancer and oncological outcomes 12 mo afterward. DESIGN, SETTING, AND PARTICIPANTS: Seventy consecutive men at a single institution with prostate cancer were prospectively enrolled. Men with prior treatment, metastases, or pelvic radiation were excluded to obtain a final cohort of 55 men. INTERVENTION: All men underwent HIFU focal therapy followed by magnetic resonance (MR)-fusion biopsy 12 mo later. Tissue change was quantified intraoperatively by measuring the backscatter of ultrasound waves during ablation. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Gleason grade group (GG) ≥2 cancer on postablation biopsy was the primary outcome. Secondary outcomes included GG ≥1 cancer, Prostate Imaging Reporting and Data System (PI-RADS) scores ≥3, and evidence of tissue destruction on post-treatment magnetic resonance imaging (MRI). A Student's t - test analysis was performed to evaluate the mean TCM scores and efficacy of ablation measured by histopathology. Multivariate logistic regression was also performed to identify the odds of residual cancer for each unit increase in the TCM score. RESULTS AND LIMITATIONS: A lower mean TCM score within the region of the tumor (0.70 vs 0.97, p = 0.02) was associated with the presence of persistent GG ≥2 cancer after HIFU treatment. Adjusting for initial prostate-specific antigen, PI-RADS score, Gleason GG, positive cores, and age, each incremental increase of TCM was associated with an 89% reduction in the odds (odds ratio: 0.11, confidence interval: 0.01-0.97) of having residual GG ≥2 cancer on postablation biopsy. Men with higher mean TCM scores (0.99 vs 0.72, p = 0.02) at the time of treatment were less likely to have abnormal MRI (PI-RADS ≥3) at 12 mo postoperatively. Cases with high TCM scores also had greater tissue destruction measured on MRI and fewer visible lesions on postablation MRI. CONCLUSIONS: Tissue change measured using TCM values during focal HIFU of the prostate was associated with histopathology and radiological outcomes 12 mo after the procedure. PATIENT SUMMARY: In this report, we looked at how well ultrasound changes of the prostate during focal high-intensity focused ultrasound (HIFU) therapy for the treatment of prostate cancer predict patient outcomes. We found that greater tissue change measured by the HIFU device was associated with less residual cancer at 1 yr. This tool should be used to ensure optimal ablation of the cancer and may improve focal therapy outcomes in the future.


Asunto(s)
Tratamiento con Ondas de Choque Extracorpóreas , Neoplasias de la Próstata , Masculino , Humanos , Neoplasias de la Próstata/diagnóstico por imagen , Neoplasias de la Próstata/cirugía , Imagen por Resonancia Magnética/métodos , Neoplasia Residual , Resultado del Tratamiento , Biopsia Guiada por Imagen
6.
Urol Oncol ; 40(11): 489.e9-489.e17, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-36058811

RESUMEN

PURPOSE: To evaluate the performance of multiparametric magnetic resonance imaging (mpMRI) and PSA testing in follow-up after high intensity focused ultrasound (HIFU) focal therapy for localized prostate cancer. METHODS: A total of 73 men with localized prostate cancer were prospectively enrolled and underwent focal HIFU followed by per-protocol PSA and mpMRI with systematic plus targeted biopsies at 12 months after treatment. We evaluated the association between post-treatment mpMRI and PSA with disease persistence on the post-ablation biopsy. We also assessed post-treatment functional and oncological outcomes. RESULTS: Median age was 69 years (Interquartile Range (IQR): 66-74) and median PSA was 6.9 ng/dL (IQR: 5.3-9.9). Of 19 men with persistent GG ≥ 2 disease, 58% (11 men) had no visible lesions on MRI. In the 14 men with PIRADS 4 or 5 lesions, 7 (50%) had either no cancer or GG 1 cancer at biopsy. Men with false negative mpMRI findings had higher PSA density (0.16 vs. 0.07 ng/mL2, P = 0.01). No change occurred in the mean Sexual Health Inventory for Men (SHIM) survey scores (17.0 at baseline vs. 17.7 post-treatment, P = 0.75) or International Prostate Symptom Score (IPSS) (8.1 at baseline vs. 7.7 at 24 months, P = 0.81) after treatment. CONCLUSIONS: Persistent GG ≥ 2 cancer may occur after focal HIFU. mpMRI alone without confirmatory biopsy may be insufficient to rule out residual cancer, especially in patients with higher PSA density. Our study also validates previously published studies demonstrating preservation of urinary and sexual function after HIFU treatment.


Asunto(s)
Imágenes de Resonancia Magnética Multiparamétrica , Neoplasias de la Próstata , Masculino , Humanos , Anciano , Próstata/patología , Antígeno Prostático Específico , Neoplasia Residual , Neoplasias de la Próstata/diagnóstico por imagen , Neoplasias de la Próstata/cirugía , Progresión de la Enfermedad
7.
Macromol Biosci ; 22(11): e2200270, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-36100461

RESUMEN

Polymer assemblies on the nanoscale represent a powerful toolbox for the design of theranostic systems when combined with both therapeutic compounds and diagnostic reporting ones. Here, recent advances in the design of theranostic systems for various diseases, containing-in their architecture-either polymers or polymer assemblies as one of the building blocks are presented. This review encompasses the general principles of polymer self-assembly, from the production of adequate copolymers up to supramolecular assemblies with theranostic functionality. Such polymer nanoassemblies can be further tailored through the incorporation of inorganic nanoparticles to endow them with multifunctional therapeutic and/or diagnostic features. Systems that change their architecture or properties in the presence of stimuli are selected, as responsivity to changes in the environment is a key factor for enhancing efficiency. Such theranostic systems are based on the intrinsic properties of copolymers or one of the other components. In addition, systems with a more complex architecture, such as multicompartments, are presented. Selected systems indicate the advantages of such theranostic approaches and provide a basis for further developments in the field.


Asunto(s)
Nanopartículas , Polímeros , Polímeros/uso terapéutico , Medicina de Precisión , Nanopartículas/uso terapéutico , Nanomedicina Teranóstica
8.
J Nucl Med ; 63(12): 1829-1835, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-35552245

RESUMEN

68Ga-RM2 targets gastrin-releasing peptide receptors (GRPRs), which are overexpressed in prostate cancer (PC). Here, we compared preoperative 68Ga-RM2 PET to postsurgery histopathology in patients with newly diagnosed intermediate- or high-risk PC. Methods: Forty-one men, 64.0 ± 6.7 y old, were prospectively enrolled. PET images were acquired 42-72 min (median ± SD, 52.5 ± 6.5 min) after injection of 118.4-247.9 MBq (median ± SD, 138.0 ± 22.2 MBq) of 68Ga-RM2. PET findings were compared with preoperative multiparametric MRI (mpMRI) (n = 36) and 68Ga-PSMA11 PET (n = 17) and correlated to postprostatectomy whole-mount histopathology (n = 32) and time to biochemical recurrence. Nine participants decided to undergo radiation therapy after study enrollment. Results: All participants had intermediate- (n = 17) or high-risk (n = 24) PC and were scheduled for prostatectomy. Prostate-specific antigen was 8.8 ± 77.4 (range, 2.5-504) and 7.6 ± 5.3 ng/mL (range, 2.5-28.0 ng/mL) when participants who ultimately underwent radiation treatment were excluded. Preoperative 68Ga-RM2 PET identified 70 intraprostatic foci of uptake in 40 of 41 patients. Postprostatectomy histopathology was available in 32 patients in which 68Ga-RM2 PET identified 50 of 54 intraprostatic lesions (detection rate = 93%). 68Ga-RM2 uptake was recorded in 19 nonenlarged pelvic lymph nodes in 6 patients. Pathology confirmed lymph node metastases in 16 lesions, and follow-up imaging confirmed nodal metastases in 2 lesions. 68Ga-PSMA11 and 68Ga-RM2 PET identified 27 and 26 intraprostatic lesions, respectively, and 5 pelvic lymph nodes each in 17 patients. Concordance between 68Ga-RM2 and 68Ga-PSMA11 PET was found in 18 prostatic lesions in 11 patients and 4 lymph nodes in 2 patients. Noncongruent findings were observed in 6 patients (intraprostatic lesions in 4 patients and nodal lesions in 2 patients). Sensitivity and accuracy rates for 68Ga-RM2 and 68Ga-PSMA11 (98% and 89% for 68Ga-RM2 and 95% and 89% for 68Ga-PSMA11) were higher than those for mpMRI (77% and 77%, respectively). Specificity was highest for mpMRI with 75% followed by 68Ga-PSMA11 (67%) and 68Ga-RM2 (65%). Conclusion: 68Ga-RM2 PET accurately detects intermediate- and high-risk primary PC, with a detection rate of 93%. In addition, 68Ga-RM2 PET showed significantly higher specificity and accuracy than mpMRI and a performance similar to 68Ga-PSMA11 PET. These findings need to be confirmed in larger studies to identify which patients will benefit from one or the other or both radiopharmaceuticals.


Asunto(s)
Radioisótopos de Galio , Neoplasias de la Próstata , Masculino , Humanos , Oligopéptidos , Receptores de Bombesina , Neoplasias de la Próstata/diagnóstico por imagen , Neoplasias de la Próstata/cirugía , Neoplasias de la Próstata/patología , Prostatectomía , Tomografía de Emisión de Positrones/métodos , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos
9.
Urology ; 162: 42-48, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-33798557

RESUMEN

Equations estimating the glomerular filtration rate are important clinical tools in detecting and managing kidney disease. Urologists extensively use these equations in clinical decision making. For example, the estimated glomerular function rate is used when considering the type of urinary diversion following cystectomy, selecting systemic chemotherapy in managing urologic cancers, and deciding the type of cross-sectional imaging in diagnosing or staging urologic conditions. However, these equations, while widely accepted, are imprecise and adjust for race which is a social, not a biologic construct. The recent killings of unarmed Black Americans in the US have amplified the discussion of racism in healthcare and has prompted institutions to reconsider the role of race in estimation of glomerular filtration rate equations and raced-based medicine. Urologist should be aware of the consequences of removing race from these equations, potential alternatives, and how these changes may affect Black patients receiving urologic care.


Asunto(s)
Enfermedades Renales , Derivación Urinaria , Negro o Afroamericano , Población Negra , Femenino , Tasa de Filtración Glomerular , Humanos , Masculino
11.
Urology ; 155: 70-76, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34139251

RESUMEN

OBJECTIVES: To determine if an automatically calculated electronic health record score can estimate intermediate-term life expectancy in men with prostate cancer to provide guideline concordant care. METHODS: We identified all men (n = 36,591) diagnosed with prostate cancer in 2013-2015 in the VHA. Of the 36,591, 35,364 (96.6%) had an available Care Assessment Needs (CAN) score (range: 0-99) automatically calculated in the 30 days prior to the date of diagnosis. It was designed to estimate short-term risks of hospitalization and mortality. We fit unadjusted and multivariable Cox proportional hazards regression models to determine the association between the CAN score and overall survival among men with prostate cancer. We compared CAN score performance to two established comorbidity measures: The Charlson Comorbidity Index and Prostate Cancer Comorbidity Index (PCCI). RESULTS: Among 35,364 men, the CAN score correlated with overall stage, with mean scores of 46.5 ( ± 22.4), 58.0 ( ± 24.4), and 68.1 ( ± 24.3) in localized, locally advanced, and metastatic disease, respectively. In both unadjusted and adjusted models for prostate cancer risk, the CAN score was independently associated with survival (HR = 1.23 95%CI 1.22-1.24 & adjusted HR = 1.17 95%CI 1.16-1.18 per 5-unit change, respectively). The CAN score (overall C-Index 0.74) yielded better discrimination (AUC = 0.76) than PCCI (AUC = 0.65) or Charlson Comorbidity Index (AUC = 0.66) for 5-year survival. CONCLUSION: The CAN score is strongly associated with intermediate-term survival following a prostate cancer diagnosis. The CAN score is an example of how learning health care systems can implement multi-dimensional tools to provide fully automated life expectancy estimates to facilitate patient-centered cancer care.


Asunto(s)
Esperanza de Vida , Neoplasias de la Próstata/mortalidad , Anciano , Estudios de Cohortes , Registros Electrónicos de Salud , Humanos , Masculino , Neoplasias de la Próstata/patología , Análisis de Supervivencia , Estados Unidos/epidemiología , United States Department of Veterans Affairs
12.
J Urol ; 206(3): 604-612, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-33878887

RESUMEN

PURPOSE: Targeted biopsy improves prostate cancer diagnosis. Accurate prostate segmentation on magnetic resonance imaging (MRI) is critical for accurate biopsy. Manual gland segmentation is tedious and time-consuming. We sought to develop a deep learning model to rapidly and accurately segment the prostate on MRI and to implement it as part of routine magnetic resonance-ultrasound fusion biopsy in the clinic. MATERIALS AND METHODS: A total of 905 subjects underwent multiparametric MRI at 29 institutions, followed by magnetic resonance-ultrasound fusion biopsy at 1 institution. A urologic oncology expert segmented the prostate on axial T2-weighted MRI scans. We trained a deep learning model, ProGNet, on 805 cases. We retrospectively tested ProGNet on 100 independent internal and 56 external cases. We prospectively implemented ProGNet as part of the fusion biopsy procedure for 11 patients. We compared ProGNet performance to 2 deep learning networks (U-Net and holistically-nested edge detector) and radiology technicians. The Dice similarity coefficient (DSC) was used to measure overlap with expert segmentations. DSCs were compared using paired t-tests. RESULTS: ProGNet (DSC=0.92) outperformed U-Net (DSC=0.85, p <0.0001), holistically-nested edge detector (DSC=0.80, p <0.0001), and radiology technicians (DSC=0.89, p <0.0001) in the retrospective internal test set. In the prospective cohort, ProGNet (DSC=0.93) outperformed radiology technicians (DSC=0.90, p <0.0001). ProGNet took just 35 seconds per case (vs 10 minutes for radiology technicians) to yield a clinically utilizable segmentation file. CONCLUSIONS: This is the first study to employ a deep learning model for prostate gland segmentation for targeted biopsy in routine urological clinical practice, while reporting results and releasing the code online. Prospective and retrospective evaluations revealed increased speed and accuracy.


Asunto(s)
Aprendizaje Profundo , Procesamiento de Imagen Asistido por Computador/métodos , Próstata/diagnóstico por imagen , Neoplasias de la Próstata/diagnóstico , Conjuntos de Datos como Asunto , Estudios de Factibilidad , Humanos , Biopsia Guiada por Imagen/métodos , Imagen por Resonancia Magnética Intervencional , Masculino , Imagen Multimodal/métodos , Imágenes de Resonancia Magnética Multiparamétrica , Prueba de Estudio Conceptual , Estudios Prospectivos , Próstata/patología , Neoplasias de la Próstata/patología , Reproducibilidad de los Resultados , Estudios Retrospectivos , Programas Informáticos , Factores de Tiempo , Ultrasonografía Intervencional/métodos
13.
Artículo en Inglés | MEDLINE | ID: mdl-22939329

RESUMEN

OBJECTIVE: The present study tested the reliability of an optical scanning device for the objective assessment of postoperative facial swelling. STUDY DESIGN: Twenty control subjects bearing a defined volume of water (10-30 mL) in an intraorally carried balloon were tested to assess the measurement accuracy of the device. As a proof of concept, facial volumes of 59 surgical cases were recorded before osteotomy and 1 and 7 days after intervention with the use of a structured light scanner. RESULTS: The median difference between the applied and the measured volumes was 0.67 mL for the control test with the artificial swelling simulated using water balloons. For subjects having third molar osteotomy, extraoral volume increased to 5.29 cm(3) 1 day after surgery (95% CI 5.22-8.52) and decreased to 0.00 mL (95% CI 0.85-2.55) after 7 days. CONCLUSIONS: Contact-free visible-light 3-dimensional scanning is reliable for the objective assessment of postoperative facial swelling.


Asunto(s)
Cara/fisiopatología , Imagenología Tridimensional/métodos , Tercer Molar/cirugía , Osteotomía/métodos , Complicaciones Posoperatorias/patología , Extracción Dental/efectos adversos , Diente Impactado/cirugía , Adulto , Estudios de Casos y Controles , Cara/anatomía & histología , Femenino , Humanos , Masculino , Reproducibilidad de los Resultados
14.
J Acoust Soc Am ; 119(2): 1214-26, 2006 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16521782

RESUMEN

The speed of ultrasound at 20 MHz differs inside human teeth depending on which tissues are involved. At least two out of four dental tissues exhibit variations in the longitudinal velocity (CL). The aim of this in vitro study is to describe the laterally varying propagation velocity of tangentially propagating longitudinal waves. At a distance of 5 mm from the crown reference, the CL is determined using longitudinal sections and a pulse-echo technique. Several graphs are combined to account for the corono-apical decrease in CL and the laterally varying CL distribution along horizontally adjacent relative tooth width portions. The laterally increasing CL of 21 specimens at radial locations rises from 2900 to 4000 m/s. A mathematical evaluation reveals an optimal horizontal formula of the form CL(5 mm) = a + bX2 ln(X), where X is the standardized lateral parameter relative to individual tooth width w, which is compensated for offsets. Individual residuals and a, b coefficients of the corresponding approximations are provided. Individual mean errors range from 7 m/s (SD=6 m/s) to 92 m/s (SD=79 m/s). The lower contour of the envelope curve of all CL distributions is described by taking up a formerly introduced equation [J. Acoust. Soc. Am. 116, 545 (2004)].


Asunto(s)
Diente/anatomía & histología , Diente/diagnóstico por imagen , Ultrasonido , Adulto , Factores de Edad , Humanos , Técnicas In Vitro , Persona de Mediana Edad , Ultrasonografía
15.
J Biomech ; 39(13): 2388-96, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16185699

RESUMEN

There is no quantitative description available that numerically relates any acoustic parameter pattern or the local elastic behaviour to any standardized geometrical positions within human teeth. However, the speed of ultrasound at 20MHz varies in different parts of teeth. Great differences occur between the values attributed to longitudinal waves that propagate in the three mineralized human hard tissues at identical relative tooth width portions [John, C., 2004. The corono-apically varying ultrasonic velocity in human hard dental tissues. Journal of the Acoustical Society of America 116, 545-556]. The aim of this work was to investigate the distribution of the longitudinal ultrasound velocity (LUV) at distinct relative tooth width portions and at a height level of 8mm relative to the coronal reference. Individual tooth widths w were accounted for, and a standardized, dimensionless radial distances variable X=|x/w-0.5| was utilized to express the radial position of measurements in a unified way. The observed lateral increase in LUV of 21 specimens along X was approximated. A Padé shape function predicts the lower contour of the envelope curve of all the individual LUV distributions. Individual residuals and coefficients are provided for LUV=a+b.ln(X).X.X, where a and b represent individual intercepts and slope factors (e.g. a=3206 m/s and b=-4184 m/s), respectively.


Asunto(s)
Dentina , Diente , Ultrasonido , Humanos
16.
J Acoust Soc Am ; 116(1): 545-56, 2004 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-15296014

RESUMEN

The speed of ultrasound at 20 MHz is measured for hard dental tissues inside human teeth. This includes the cementum, for which no data are available. The spatial distribution, extrema, and means of the longitudinal ultrasound velocity (LUV) are determined with an emphasis on the apical thirds and an extended spectrum. Tissue areas are investigated by optical means and by acoustical scanning, in order to compare apical regions-of-interest with the complete mineralized wet porous tissue that lies beneath the enamel cap. The maximal LUV in a single dentin specimen varies from 3903 m/s to 4226 m/s. The dentin's frequency distribution of LUV at 20 degrees C exhibits a predominant peak feature comprising several Voigt functions. Introducing standardized relative tooth width portions, the corono-apical decrease in LUV of 21 specimens is approximated by LUV=4224 - (257* ln(y)) along reduced distances in dentin. Abnormal teeth require a higher resolution and an approximate equation of the form LUV= (sigma(ai*yi))/(1 + sigma(bi+1*y(i+1. It can be used each time the corono-apical variation has to be quantified in each of the three tissues. Ten coefficients are numerically exemplified. An error evaluation is performed, which denotes errors of 0.2% +/- 1.3% (enamel), -0.1% +/- 1.6% (cementum), and acceptable residual errors for dentin.


Asunto(s)
Cemento Dental/diagnóstico por imagen , Esmalte Dental/diagnóstico por imagen , Dentina/diagnóstico por imagen , Diente/diagnóstico por imagen , Ultrasonido , Adolescente , Adulto , Anciano , Niño , Cemento Dental/anatomía & histología , Esmalte Dental/anatomía & histología , Dentina/anatomía & histología , Humanos , Persona de Mediana Edad , Diente/anatomía & histología , Ultrasonografía
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