Pain Medication Frequency and Fall Risk Among Community-Dwelling Older Adults With Arthritis.

Pain medication is commonly used among older adults with arthritis, elevating the risk of falling. We examined fall risks related to the frequency of taking pain medication among community-dwelling older adults with arthritis by analyzing a nationally representative sample of community-dwelling Medicare beneficiaries aged >65 with self-reported arthritis (n = 4,225) in the 2015 National Health and Aging Trends Study. The survey-weighted logistic regression revealed that after controlling for confounding factors, recent falls were associated with taking pain medication daily compared to never (OR = 1.45, 95% CI: 1.06, 1.96). The other categories of medication frequency, compared to never, were not associated with fall risk. Findings suggest that more prudent use of pain medication should be stressed by health care providers for older adults with arthritis to help reduce the risk of falls and fall injuries. Nonpharmacological pain management is encouraged to support active living among older adults with arthritis.

Supramolecular nanosheet formation-induced photosensitisation mechanism change of Rose Bengal dye in aqueous media.

Development of two-dimensional materials and exploration of their functionalities are significant challenges due to their potential. In this study, we successfully fabricated a supramolecular nanosheet composed of amphiphilic Rose Bengal dyes in an aqueous medium. Furthermore, we elucidated a distinct change in the photosensitisation mechanism induced by nanosheet formation.

Use of Caregiving Support Services Among Diverse Dementia Caregivers by Geographic Context.

BACKGROUND AND OBJECTIVES: Little is known about how race/ethnicity and geographic context relate to support service use among dementia caregivers. Our objectives were to investigate (a) whether the use of at least one formal caregiving service-support groups, respite care, and training-differed by race/ethnicity and across metro and nonmetro areas; and (b) whether predisposing, enabling, and need characteristics influenced support service use by race/ethnicity. RESEARCH DESIGN AND METHODS: Data were analyzed from a sample of primary caregivers of care recipients aged 65 years or older with probable dementia (n = 482) in the 2017 National Health and Aging Trends Study and National Study of Caregiving. We calculated weighted prevalence estimates and then used the Hosmer-Lemeshow goodness of fit statistic to find the best-fitting logistic regression models. RESULTS: Among minority dementia caregivers, support service use was higher in metro than nonmetro areas (35% and 15%); the trend was reversed for non-Hispanic White caregivers (47% nonmetro and 29% metro). The best-fitting regression models included predisposing, enabling, and need factors for both minority and non-Hispanic White caregivers. Younger age and more disagreement within the family were consistently associated with more service use in both groups. Among minority caregivers, better caregiver and care recipient health were associated with using support services. Among non-Hispanic White caregivers, nonmetro geographic context and caregiving interfering with valued activities were associated with using support services. DISCUSSION AND IMPLICATIONS: Geographic context differently affected support service use and the influence of predisposing, enabling, and need factors varied by race/ethnicity.

Dementia Caregiving Experiences and Health Across Geographic Contexts by Race and Ethnicity.

OBJECTIVES: Few studies have examined how the intersectionality of geographic context and race/ethnicity influences dementia caregiving. Our objectives were to determine whether caregiver experiences and health (a) differed across metro and nonmetro areas and (b) differed by caregiver race/ethnicity and geography. METHODS: We used data from the 2017 National Health and Aging Trends Study and National Study of Caregiving. The sample included caregivers (n = 808) of care recipients ages 65 and older with "probable" dementia (n = 482). The geographic context was defined as the care recipient's residence in metro or nonmetro counties. Outcomes included caregiving experiences (care situation, burden, and gains) and health (self-rated anxiety, depression symptoms, and chronic health conditions). RESULTS: Bivariate analyses indicated that nonmetro dementia caregivers were less racially/ethnically diverse (82.7% White, non-Hispanic) and more were spouses/partners (20.2%) than their metro counterparts (66.6% White, non-Hispanic; 13.3% spouses/partners). Among racial/ethnic minority dementia caregivers, nonmetro context was associated with more chronic conditions (p < .01), providing less care (p < .01), and not coresiding with care recipients (p < .001). Multivariate analyses demonstrated that nonmetro minority dementia caregivers had 3.11 times higher odds (95% confidence interval [CI] = 1.11-9.00) of reporting anxiety in comparison to metro minority dementia caregivers. DISCUSSION: Geographic context shapes dementia caregiving experiences and caregiver health differently across racial/ethnic groups. Findings are consistent with previous studies that have shown that feelings of uncertainty, helplessness, guilt, and distress are more prevalent among people providing caregiving from a distance. Despite higher rates of dementia and dementia-related mortality in nonmetro areas, findings suggest both positive and negative aspects of caregiving among White and racial/ethnic minority caregivers.

Three-dimensional visualization of thoracodorsal artery perforators using photoacoustic imaging✰,✰✰.

INTRODUCTION: Diagnostic imaging modalities to evaluate the three-dimensional distribution of thoracodorsal artery perforators (TDAPs) are lacking. In this study, TDAPs were visualized and characterized using photoacoustic imaging. MATERIAL AND METHODS: In this study, 34 sites in the lateral chest wall of 18 individuals were analyzed. The region extending 5 cm ventral and 5 cm dorsal to the lateral edge of the latissimus dorsi (LD) and 5-15 cm from the posterior axillary fold was scanned using photoacoustic imaging. The largest perforator closest to the edge of the LD was characterized. The location of the stem portion and the orientation of the longest cutaneous branch of the perforator were described. The relationship between the maximal depth of delineation on photoacoustic images and the depth of the deep fascia was assessed. RESULTS: On average, 2.6 perforators (range, 1-5 perforators) were visualized in the region of interest. The distribution of the TDAP stem portion was similar to that in previous studies. Cutaneous branches were preferentially oriented in a medial-caudal direction. The length of delineated cutaneous branches varied (range, 7-78 mm) depending on the thickness of the subcutaneous layer. Vessels under the LD were observed when the subcutaneous layer was thin. CONCLUSION: Photoacoustic imaging can successfully visualize TDAPs in three dimensions. Visualization of TDAPs varied by the thickness of the subcutaneous layer. A thin deep fascia of the LD might be a cause of deep laser penetration.

An Analysis of Health Care Team Communication Needs Among Younger vs Older Breast Cancer Survivors: Web-Based Survey.

BACKGROUND: Prior studies indicate that the age of onset of breast cancer is an important element in considering communication between patients and the health care team. Younger women aged 45 and under diagnosed with breast cancer are often at a higher risk of being more vulnerable to psychosocial issues compared to older women aged 46 years and above. Few studies have examined age differences in patient perceptions of treatment-related discussion and communication during transition with their health care team. OBJECTIVE: The aims of this survey were (1) to better understand breast cancer survivors' perspectives regarding communication with health care providers during treatment and during transition to posttreatment care; and (2) to determine the differences between younger women with breast cancer (≤45 years of age) and older women (≥46 years of age). It was hypothesized that (1) breast cancer survivors' psychosocial and finance-related communications with health care providers may lack effectiveness; (2) younger women experience greater needs for patient-centered communication with physicians and health care providers, especially about psychosocial care and transition to posttreatment care; and (3) younger breast cancer patients (≤45 years of age) need more information on survivorship and follow-up care. METHODS: An internet-based survey was conducted with 143 women in Central Texas with 35% (n=50) aged 45 years or under and 65% (n=93) aged 46 years and above. The Mann-Whitney U test was performed to assess differences in participants' perceptions about communication with health care providers by age group: younger (≤45 years of age) and older (≥46 years of age) women. RESULTS: Statistically significant results pertained to rating health care team and patient discussions about transition from treatment to posttreatment using scores of 0 as "no discussion" and 100 as "in-depth discussion." For the questions about management of posttreatment care, the overall mean score of the groups was 56.26 and that of the younger group was 43.96; the mean score of the older group was 61.96 (P=.02). For the question about the timing of follow-up appointments, the overall mean score was 64.29; the mean score of the younger group was 54.44, and that of the older group was 68.88 (P=.05). All the group scores related to psychosocial and financial support discussions with health care providers were low, with a rollup average of only 30.02 out of 100, suggesting that this is an important area for improving patient-centered communication. CONCLUSIONS: For all patients, transition from treatment to posttreatment requires a greater level of engagement and communication with the health care team. It appears that younger patients aged ≤45 years require more in-depth and personalized messaging to better understand their posttreatment care requirements.

A Multi-Level Analyses of Charges and Cost of Fall-Related Hospitalizations Among Older Adults: Individual, Hospital, and Geospatial Variation.

The growing population of older adults has attracted concern from policymakers due in part to the fact that they are at higher risk of costly and potentially injurious falls. Responding to this concern, this study investigated fall-related hospitalizations among those aged 65 and older. Hospitalizations rose from 49,299 to 58,931, with charges and costs (estimated based on charges) increasing from $2.5 billion to $3.6 billion and under $900 million to over $1.1 billion, respectively. The intraclass correlation coefficients from linear mixed-effect models (with charges and costs serving as dependent variables) indicated differences in hospitals accounted for nearly half or more of medical cost variation among older adults suffering a fall-related hospitalization. Nonmetropolitan residence, being aged 65-69 (versus older), and higher risk-of-mortality on admission indicated higher costs. Identifying trends of fall-related hospitalizations over time allows for key stakeholders to not only track the burden of falls among older adults but to also use this information to attract funding for fall prevention strategies from policy makers at various levels (e.g., locally, at the state). Further, identifying characteristics of individuals (e.g., age, race, sex) and places (e.g., rural areas) that carry a higher relative cost can serve to inform the targeted allocation of finite resources including local, state, or federal funding, but also existing evidence-based practices such as community and clinical interventions.

Differential risk of falls associated with pain medication among community-dwelling older adults by cognitive status.

BACKGROUND: Persons living with dementia have an elevated risk of falling and chronic pain. This study investigates the relationship of pain medication use with falls among community-dwelling adults based on their cognitive status. METHODS: We analysed a nationally representative sample of community-dwelling Medicare beneficiaries (n = 7,491) who completed cognitive assessments used for dementia classification in the 2015 US National Health and Aging Trends Study. We performed survey-weighted logistic regression to investigate differential associations between pain medication use and a recent fall by cognitive status: no dementia, possible dementia and probable dementia, controlling for sociodemographic and health characteristics. RESULTS: About 16.5% of the analytic sample was classified as possible dementia (8.3%) and probable dementia (8.2%). Pain medication use was associated with a recent fall among those with probable dementia [odds ratio (OR) = 1.86, 95% confidence interval (CI): 1.14, 3.03], controlling for sociodemographic and health characteristics. Taking medication for pain 2 days a week or more (OR = 2.14, 95% CI: 1.20, 3.81) was associated with falls among those with probable dementia. Bothersome pain and worry about falling down were also associated with falls among participants with no dementia and possible dementia, respectively. CONCLUSION: Differential risk factors for falls by cognitive status imply the need for tailored pain management and fall prevention strategies. The provision of fall prevention programmes stressing balance training and medication use is important regardless of cognitive status in community-dwelling older adults. Future research should explore other modifiable factors associated with the risk of falls among community-dwelling adults.

The role of improved social support for healthy eating in a lifestyle intervention: Texercise Select.

OBJECTIVE: We examined the measurement and mediating role of social support in dietary intake among participants in Texercise Select, an intervention for improving lifestyle behaviours. DESIGN: Quasi-experimental study. Participants reported their dietary intake, level of social support measured by the new Social Support for Healthy Eating scale, sociodemographics and disease profile. We conducted exploratory factor analysis for scale evaluation and structural equation modelling for mediation analysis to test if changes in dietary-specific social support mediate the relationship between the intervention and changes in dietary intake. SETTING: Texas. PARTICIPANTS: Community-dwelling middle-aged and older adults completed a self-reported survey at baseline and 3-month follow-up (intervention group n 211, comparison group n 175). RESULTS: The majority of the sample was aged ≥70 years (mean 74·30, sd 8·54), female (82·1 %) and had at least two chronic conditions (63·5 %). The acceptable levels of reliability and validity of the dietary-specific social support scale were confirmed. Compared with the comparison group, the intervention group reported improved intake of fruit/vegetables and water, and improved dietary-specific social support. Improved dietary-specific social support mediated the association between intervention and change in fruit/vegetable intake, controlling for sociodemographics, number of chronic conditions and geographic residence. About 12 % of intervention effect was mediated by social support. CONCLUSIONS: The current study confirms positive intervention effects on healthy eating, and highlights social support relating to dietary behaviours that may be helpful for healthy eating. Future research should investigate additional social support for developing healthy eating behavioural skills.

Perceptions of a mobile phone-based approach to promote medication adherence: A cross-sectional application of the technology acceptance model.

Background: In several African and Asian countries, callers to mobile phones sometimes hear a song or message in place of the typical ringing sound. This application, called caller tunes, may offer a unique opportunity to promote medication adherence that is yet to be explored. Objectives: Assess the application of the technology acceptance model to a potential caller tunes approach designed to enhance medication adherence, with a specific focus on the interrelationships of perceived ease of use, perceived usefulness, cost, and intention. Methods: Data from a cross-sectional sample of 996 adult mobile phone users in Ghana, approximately half of whom were current caller tunes users, was examined using exploratory factor analysis for scale evaluation and structural equation modeling to assess associations among perceived ease of use, perceived usefulness, and cost on intention to use mobile phone caller tunes to promote medication adherence. Results: Consistent with the technology acceptance model, intention to use the caller tunes as a means of enhancing medication adherence was higher among those who viewed the application positively in terms of ease of use and usefulness. Among those who were already caller tunes users, availability as a free download was also associated with more positive intentions. Conclusion: The present study provides preliminary evidence in support of caller tunes as a novel strategy to promote medication adherence. Future studies interested in using this approach would be advised to consider factors such as participants' current use of caller tunes, age, availability as a free download, and perceptions of ease of use and perceived usefulness of the approach as potential moderators of study outcomes.

Systematic review and meta-analysis of fear of falling and fall-related efficacy in a widely disseminated community-based fall prevention program.

BACKGROUND: Fear of falling restricts mobility and increases fall risk among older adults. Fall-related efficacy (i.e. the confidence to perform activities without falling), a construct related to fear of falling, has also been associated with active living and fall prevention. This study statistically synthesized the program effects of A Matter of Balance Volunteer Lay Leader (AMOB/VLL) model, designed to improve fall-related efficacy and promote daily activities among community-dwelling older adults. METHODS: Research articles and doctoral dissertations that examined the effect of the AMOB/VLL on fear of falling and fall-related efficacy were searched from multiple databases. A random effects model was used to compute mean weighted effect sizes, 95 % CIs, and heterogeneity (I2). Bias was examined through a funnel plot and Egger's test. Factors associated with heterogeneity were also explored. RESULTS: Seventeen AMOB/VLL studies involving 3,860 participants were identified. The pooled effects of the 13 studies with sufficient information for effect size calculation, were -0.29 (95 % CI: -0.40, -0.19) for fear of falling and 0.51 (95 % CI: 0.42, 0.60) for fall-related efficacy. Effect sizes differed partially due to outcome measures of fall-related efficacy. Covariate adjustment and study quality were not associated with differences in effect sizes. No substantial evidence of asymmetry and publication bias was found. CONCLUSION: This study provides evidence supporting AMOB/VLL as an effective intervention for reducing fear of falling and improving fall-related efficacy. A greater consistency in outcome measures is needed to optimally capture changes in fear of falling and fall-related efficacy among community-dwelling older adults.

Opioid Use and the Risk of Falls, Fall Injuries and Fractures among Older Adults: A Systematic Review and Meta-Analysis.

BACKGROUND: There is increasing concern about opioid use as a pain treatment option among older adults. Existing literature implies an association between opioid use and fracture, increasing the risk of death and disabilities; yet, this relationship with other fall-related outcomes has not been fully explored. We performed a meta-analysis to evaluate the associations between opioid use and adverse health outcomes of falls, fall injuries, and fractures among older adults. METHODS: A systematic literature search was conducted using nine databases: Medline, Embase, CINAHL, PsycInfo, Global Health, Northern Light Sciences Conference Abstracts, Cochrane CENTRAL, WHO International Clinical Trials Registry Platform, and ClinicalTrials.gov. We log-transformed effect sizes (relative risk [RR], odds ratio [OR], and hazard ratio [HR]) to compute pooled risk estimates comparable across the studies. The random-effects model was applied to calculate the pooled risk estimates due to heterogeneity. Meta-regressions explored differences in risk estimates by analysis method, study design, setting, and study quality. RESULTS: Thirty studies, providing 34 relevant effect sizes, met the inclusion criteria for this meta-analysis. Overall, opioid use was significantly associated with falls, fall injuries, and fractures, with effect sizes ranging from 0.15 to 0.71. In meta-regressions, no selected factors explained heterogeneity. CONCLUSION: While heterogeneity is present, results suggest an increased risk of falls, fall injuries, and fractures among older adults who used opioids. Findings highlight the need for opioid education and nonopioid-related pain management interventions among older adults to decrease fall-related risk.

Preoperative vascular mapping for anterolateral thigh flap surgeries: A clinical trial of photoacoustic tomography imaging.

BACKGROUND: Photoacoustic tomography (PAT) is a noninvasive vascular imaging modality that uses near-infrared pulse laser beams and ultrasound (US) to visualize vessels. We previously demonstrated the utility of PAT for visualizing anterolateral thigh (ALT) perforators in a clinical study of 10 thighs in 5 healthy adults. Evaluation of the correlation between PAT and US findings showed that PAT had comparable diagnostic potential but was superior in visualizing subcutaneous microvessels; however, there was no comparison with intraoperative findings. In this study, we used a newly developed technique to transfer a PAT image to a body-attachable transparent sheet to compare PAT and intraoperative findings. METHODS: Eight patients were recruited in this prospective study. Patient age ranged from 32 to 79 years (average 60). Seven ALT flaps were applied in head and neck reconstruction. One flap was elevated in chest wall reconstruction. Each PAT scan of an 18 cm × 13.5 cm region took approximately 5 min. Acquired data were processed three-dimensionally using a novel imaging software program. Perforator vessel data from PAT imaging were traced and corrected for projection onto medical film sheets. The correlation between the perforator stem portions predicted by PAT and the intraoperative findings at the level of the fascia-penetrating points was evaluated, and distal branching patterns were analyzed. RESULTS: PAT imaging showed 16 perforators in 8 thighs. Intraoperative surgical findings revealed that all the perforator penetrating points at the deep fascia level matched the PAT findings within 10 mm. None of the eight ALT flaps demonstrated postoperative complications. The perforator complexes were classified as type I in three cases (19%), type II in eight cases (50%), and type III in five cases (31%). CONCLUSIONS: PAT imaging matched the intraoperative findings within 10 mm. Preoperative vascular evaluation allows for the creation of a vascular map for facilitating ALT flap surgeries.

Mediating Role of Fall-related Efficacy in a Fall Prevention Program.

Objectives: We examined the multidimensionality of the new Perceived Ability to Prevent and Manage Fall Risks (PAPMFR) scale that assesses fall-related efficacy (FE) and the mediating role of EF between fear of falling (FOF) and functional mobility (FM). Methods: We carried out a secondary data analysis of 552 participants (mean age = 76.45, SD = 7.79) in a fall prevention program, A Matter of Balance Volunteer Lay Leader Model (AMOB/VLL). We used exploratory and confirmatory factor analyses to evaluate the PAPMFR scale. We used structural equation modeling to test the mediating role of PAPMFR between FOF and FM. Results: We identified 3 dimensions of PAPMFR: steadiness/balance, gait, and fall management. We confirmed the mediating effect of the PAPMFR on the relation between FOF and FM with acceptable fit in cross-sectional (χ²/df = 2.25, RMSEA = .06, 95% CI: .04 to .09, CFI = .98 SRMR = .03) and half-longitudinal (χ²/df = 3.04, RMSEA = .08, 95% CI: .07 to .09, CFI = .95, SRMR = .04) models. Conclusions: AMOB/VLL shows promise to enhance FE, which may mediate FM improvements among participants. Find- ings suggest that improving confidence to prevent and manage falls can complement exercise training to promote active aging. Future research should investigate various FE dimensions.

Efficacy and safety of a crystalline lactulose preparation (SK-1202) in Japanese patients with chronic constipation: a randomized, double-blind, placebo-controlled, dose-finding study.

BACKGROUND: Clinical evidence of lactulose for chronic constipation in Japan was lacking. We performed a randomized, double-blind, placebo-controlled, dose-finding study in Japanese patients with chronic constipation to estimate the optimal clinical dose of lactulose. METHODS: Overall, 250 patients were randomized to receive SK-1202 (13, 26, or 39 g/day, as crystalline lactulose dosage) or placebo twice daily (morning and evening) orally for 2 weeks. The primary endpoint was the change from baseline frequency of spontaneous bowel movements (SBMs) at Week 1. The secondary endpoints included the change from baseline of SBMs at Week 2, percentage of patients experiencing SBM within 24 and/or 48 h of the initial dose, stool consistency, and constipation severity, and adverse events were also evaluated. RESULTS: The 26 and 39 g/day of SK-1202 induced significantly and dose-dependently more increase in SBM at Week 1 than placebo (p = 0.003, p < 0.001). These groups also showed significant improvements in the secondary endpoints. There were no significant differences in the incidence of adverse drug reactions (ADRs) between the placebo and SK-1202 groups. Gastrointestinal disorder was the most common ADR, and diarrhea developed in 6 patients (9.7%) treated with 39 g/day; however, the symptoms were mild in severity and resolved after follow-up, dose reduction, or dose suspension. SK-1202 was generally well tolerated up to 39 g/day. CONCLUSION: Our results suggest that SK-1202 is useful in Japanese patients with chronic constipation, and optimal dose of SK-1202 is 26 g/day.

Digital artery deformation on movement of the proximal interphalangeal joint.

This study aimed to characterize in vivo human digital arteries in three-dimensions using photoacoustic tomography in order to understand the specific mechanism underlying arterial deformation associated with movement of the proximal interphalangeal joint. Three-dimensional morphological data were obtained on the radialis indicis artery (radial artery of the index finger) at different angles of the joint. The association between increased curvature of the deformation and the anatomical region was assessed. Characteristic morphological deformations in areas of major deformation were determined. The deformation of the artery was characterized by three consecutive curves in juxta-articular regions, which were particularly noticeable when the joint was flexed at an angle of ≥ 60°. The change in the curvature of the deformation during 30°-90° of flexion was lower in middle-aged individuals than in young individuals. Better understanding of the mechanism underlying deformation of the digital arteries may contribute to advancements in flap procedures and rehabilitation strategies after digital artery repair.

Visualising peripheral arterioles and venules through high-resolution and large-area photoacoustic imaging.

Photoacoustic (PA) imaging (PAI) has been shown to be a promising tool for non-invasive blood vessel imaging. A PAI system comprising a hemispherical detector array (HDA) has been reported previously as a method providing high morphological reproducibility. However, further improvements in diagnostic capability will require improving the image quality of PAI and fusing functional and morphological imaging. Our newly developed PAI system prototype not only enhances the PA image resolution but also acquires ultrasonic (US) B-mode images at continuous positions in the same coordinate axes. In addition, the pulse-to-pulse alternating laser irradiation shortens the measurement time difference between two wavelengths. We scanned extremities and breasts in an imaging region 140 mm in diameter and obtained 3D-PA images of fine blood vessels, including arterioles and venules. We could estimate whether a vessel was an artery or a vein by using the S-factor obtained from the PA images at two wavelengths, which corresponds approximately to the haemoglobin oxygen saturation. Furthermore, we observed tumour-related blood vessels around breast tumours with unprecedented resolution. In the future, clinical studies with our new PAI system will help to elucidate various mechanisms of vascular-associated diseases and events.

Vascular branching point counts using photoacoustic imaging in the superficial layer of the breast: A potential biomarker for breast cancer.

This study aimed to identify the characteristics of the vascular network in the superficial subcutaneous layer of the breast and to analyze differences between breasts with cancer and contralateral unaffected breasts using vessel branching points (VBPs) detected by three-dimensional photoacoustic imaging with a hemispherical detector array. In 22 patients with unilateral breast cancer, the average VBP counts to a depth of 7 mm below the skin surface were significantly greater in breasts with cancer than in the contralateral unaffected breasts (p < 0.01). The ratio of the VBP count in the breasts with cancer to that in the contralateral breasts was significantly increased in patients with a high histologic grade (p = 0.03), those with estrogen receptor-negative disease (p < 0.01), and those with highly proliferative disease (p < 0.01). These preliminary findings indicate that a higher number of VBPs in the superficial subcutaneous layer of the breast might be a biomarker for primary breast cancer.

Photoacoustic Tomography Shows the Branching Pattern of Anterolateral Thigh Perforators In Vivo.

The distal branching pattern of perforators is associated with thin anterolateral thigh flap failure. The purpose of this study was to investigate the feasibility of using photoacoustic tomography as a diagnostic imaging modality to identify anterolateral thigh perforators and their branching patterns in the subcutaneous layer. Ten thighs in five healthy men were studied. The anterolateral aspect of the midthigh was examined using photoacoustic tomography. The correlation between photoacoustic tomography and ultrasound findings was evaluated. To determine the detectability of photoacoustic tomography by depth, the depth of vessels in the stem portion was compared to the depth of the deep fascia measured by ultrasound. Branching patterns of vessels in the adipose and suprafascial layers were evaluated by three-dimensional observation. A total of 18 perforators were visualized by photoacoustic tomography. Photoacoustic tomography and ultrasound had comparable diagnostic potential for the detection of perforators. Photoacoustic tomography visualized microvessels in the subcutaneous layer, especially those in oblique or horizontal orientations. The estimated mean depth of visualized vessels was 9 mm; the maximum depth was 13 mm. There was a strong correlation between the depth of visualized vessels in the stem portion and the depth of the deep fascia. Three-dimensional observation of photoacoustic tomographic images showed the branching morphology of perforators. This study showed the applicability of photoacoustic tomography to identification of the branching patterns of anterolateral thigh perforators in vivo, although limited visualization of subfascial vessels is a technical issue. The authors believe that photoacoustic tomography has the potential to be a new imaging modality for thin anterolateral thigh flap surgery. CLINICAL QUESTION/LEVEL OF EVIDENCE: Diagnostic, IV.

Real-time 3D Photoacoustic Visualization System with a Wide Field of View for Imaging Human Limbs.

Background: A breast-specific photoacoustic imaging (PAI) system prototype equipped with a hemispherical detector array (HDA) has been reported as a promising system configuration for providing high morphological reproducibility for vascular structures in living bodies. Methods: To image the vasculature of human limbs, a newly designed PAI system prototype (PAI-05) with an HDA with a higher density sensor arrangement was developed. The basic device configuration mimicked that of a previously reported breast-specific PAI system. A new imaging table and a holding tray for imaging a subject's limb were adopted. Results: The device's performance was verified using a phantom. Contrast of 8.5 was obtained at a depth of 2 cm, and the viewing angle reached up to 70 degrees, showing sufficient performance for limb imaging. An arbitrary wavelength was set, and a reasonable PA signal intensity dependent on the wavelength was obtained. To prove the concept of imaging human limbs, various parts of the subject were scanned. High-quality still images of a living human with a wider size than that previously reported were obtained by scanning within the horizontal plane and averaging the images. The maximum field of view (FOV) was 270 mm × 180 mm. Even in movie mode, one-shot 3D volumetric data were obtained in an FOV range of 20 mm in diameter, which is larger than values in previous reports. By continuously acquiring these images, we were able to produce motion pictures. Conclusion: We developed a PAI prototype system equipped with an HDA suitable for imaging limbs. As a result, the subject could be scanned over a wide range while in a more comfortable position, and high-quality still images and motion pictures could be obtained.