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PURPOSE: Our aim was to evaluate the ocular surface in chronic smokers and to assess the benefit of sodium hyaluronate (SH) versus semi-fluorinated alkane (SFA) eyedrops on tear film, meibomian glands, and corneal epithelial thickness (CET). METHODS: This prospective randomized single-blinded study included smokers, who applied one eyedrop of Hyabak® on one eye (SH group) and one eyedrop of EvoTears® on the fellow eye (SFA group) 4 times daily for 2 months, and age-matched non-smokers. Ocular surface parameters, including tear film break-up time (TBUT) test and corneal fluorescein staining (CFS) score, lipid layer thickness (LLT), meibography (LipiView®), and CET measurements (Zeiss Cirrus HD-5000®), were assessed at baseline and after treatment. RESULTS: Seventy-eight eyes were included in the smokers group (39 in the SH subgroup and 39 in the SFA subgroup) and 42 eyes in the control group. At baseline, the smokers group had a higher prevalence of dry eye (100% vs 0%, p < 0.001) and of meibomian gland dysfunction (MGD) and lower CET measurements than controls (p < 0.05). TBUT, CFS, and LLT (controls vs SFA group: 64.02 ± 1.87 nm vs 49.56 ± 4.33 nm, p = 0.05) improved in the SFA subgroup after treatment, but not in the SH subgroup, and became equivalent to those of controls. Prevalence of dry eye decreased in the smokers group after treatment (controls vs SH group vs SFA group: 0% vs 12.82% vs 16.26%, p > 0.05). Meibomian gland morphological parameters and CET did not improve after treatment (p < 0.05). CONCLUSIONS: Smoking is associated with dry eye, MGD, and corneal epithelial thinning that seem to be only partially reversible with topical lubricants, preferably SFA.
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Síndromes do Olho Seco , Epitélio Corneano , Disfunção da Glândula Tarsal , Humanos , Glândulas Tarsais , Nicotiana , Estudos Prospectivos , Síndromes do Olho Seco/diagnóstico , Síndromes do Olho Seco/tratamento farmacológico , Síndromes do Olho Seco/etiologia , Lágrimas , LipídeosRESUMO
The association of internuclear ophthalmoplegia (INO) with exotropia in the contralateral eye is a rare finding, known as non-paralytic pontine exotropia (NPPE). We report a case of an 80-year-old woman with acute onset of diplopia on admission who presented with left eye exotropia with left-beating nystagmus whilst fixating with the right eye and inability to adduct the right eye on left gaze. Brain magnetic resonance imaging showed two small areas of vertebrobasilar territory ischaemic stroke, one beneath the inferior portion of the aqueduct and another in the right occipital lobe. Our case highlights an interesting clinical manifestation of brainstem infarction that, along with ocular motility examination, allowed us to review its pathophysiology, including the influence of the contralateral paramedian pontine reticular formation stimulation in the mechanism of contralateral exotropia in NPPE. The fast clinical resolution of these cases can explain the scarcity of NPPE reports.
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Intraoperative tissue deformation, known as brain shift, decreases the benefit of using preoperative images to guide neurosurgery. Non-rigid registration of preoperative magnetic resonance (MR) to intraoperative ultrasound (iUS) has been proposed as a means to compensate for brain shift. We focus on the initial registration from MR to predurotomy iUS. We present a method that builds on previous work to address the need for accuracy and generality of MR-iUS registration algorithms in multi-site clinical data. High-dimensional texture attributes were used instead of image intensities for image registration and the standard difference-based attribute matching was replaced with correlation-based attribute matching. A strategy that deals explicitly with the large field-of-view mismatch between MR and iUS images was proposed. Key parameters were optimized across independent MR-iUS brain tumor datasets acquired at 3 institutions, with a total of 43 tumor patients and 758 reference landmarks for evaluating the accuracy of the proposed algorithm. Despite differences in imaging protocols, patient demographics and landmark distributions, the algorithm is able to reduce landmark errors prior to registration in three data sets (5.37±4.27, 4.18±1.97 and 6.18±3.38â¯mm, respectively) to a consistently low level (2.28±0.71, 2.08±0.37 and 2.24±0.78â¯mm, respectively). This algorithm was tested against 15 other algorithms and it is competitive with the state-of-the-art on multiple datasets. We show that the algorithm has one of the lowest errors in all datasets (accuracy), and this is achieved while sticking to a fixed set of parameters for multi-site data (generality). In contrast, other algorithms/tools of similar performance need per-dataset parameter tuning (high accuracy but lower generality), and those that stick to fixed parameters have larger errors or inconsistent performance (generality but not the top accuracy). Landmark errors were further characterized according to brain regions and tumor types, a topic so far missing in the literature.
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Algoritmos , Neoplasias Encefálicas/diagnóstico por imagem , Interpretação de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Ultrassonografia/métodos , Mapeamento Encefálico/métodos , Neoplasias Encefálicas/cirurgia , Humanos , Imageamento Tridimensional/métodos , Cirurgia Assistida por Computador/métodosRESUMO
A simple and efficient procedure for the synthesis of N-acyl 4-hydroxy, 4-hydroxy-3-methoxy and 3,4-dihydroxy phenylglycine amides by a strategy based on the multicomponent Ugi reaction is proposed. Hydroxybenzaldehyde derivatives were reacted with 4-methoxybenzylamine, cyclohexyl isocyanide and benzoic acid or 2-naphthylacetic acid to give Ugi adducts that were treated with trifluoroacetic acid yielding N-acyl hydroxyphenylglycine amides in good yields. The same procedure using as acid component protocatechuic acid or hydrocaffeic acid gave N-catechoyl 3,4-dihydroxyphenylglycine amides. The use of N-benzyloxycarbonylglycine as acid component allowed the preparation of a 3,4-dihydroxyphenylglycyl dipeptide derivative. Radical-scavenging activity studies of the polyphenolic amino acid derivatives showed a sharp increase in activity with the increase in number of hydroxyl or catechol groups present. Cyclic voltammetry experiments established a correlation between oxidation peak potentials and the radical-scavenging activity.
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Aminoácidos/síntese química , Sequestradores de Radicais Livres/química , Polifenóis/química , Aminoácidos/química , Técnicas Eletroquímicas , Sequestradores de Radicais Livres/síntese química , Relação Estrutura-Atividade , Proteínas Virais/químicaRESUMO
Cine cardiac magnetic resonance (CMR) imaging is considered the gold standard for cardiac function evaluation. However, cine CMR acquisition is inherently slow and in recent decades considerable effort has been put into accelerating scan times without compromising image quality or the accuracy of derived results. In this article, we present a fully-automated, quality-controlled integrated framework for reconstruction, segmentation and downstream analysis of undersampled cine CMR data. The framework produces high quality reconstructions and segmentations, leading to undersampling factors that are optimised on a scan-by-scan basis. This results in reduced scan times and automated analysis, enabling robust and accurate estimation of functional biomarkers. To demonstrate the feasibility of the proposed approach, we perform simulations of radial k-space acquisitions using in-vivo cine CMR data from 270 subjects from the UK Biobank (with synthetic phase) and in-vivo cine CMR data from 16 healthy subjects (with real phase). The results demonstrate that the optimal undersampling factor varies for different subjects by approximately 1 to 2 seconds per slice. We show that our method can produce quality-controlled images in a mean scan time reduced from 12 to 4 seconds per slice, and that image quality is sufficient to allow clinically relevant parameters to be automatically estimated to lie within 5% mean absolute difference.
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Aprendizado Profundo , Humanos , Imagem Cinética por Ressonância Magnética/métodos , Coração/diagnóstico por imagemRESUMO
INTRODUCTION: Nutrition is vital in health and sports performance by improving anthropometric-related parameters and dietary habits, especially in the youngest ages. The Mediterranean diet (MD) has been highly recognized for its positive health effects and low adverse environmental impact. OBJECTIVES: We aimed to characterize adherence to the MD and analyze its association with anthropometric parameters in young soccer players. METHODOLOGY: In the present study, 132 male young soccer players from under 9 to under 15 categories (aged 7 to 15 years) from a Portuguese football club participated. The Mediterranean Diet Quality Index for Children and Adolescents (KIDMED) questionnaire was applied to assess adherence to the MD. Anthropometric-related parameters, including body mass, height, triceps skinfold thickness (TSKF), suprailiac skinfold thickness (SISKF), body mass index (BMI) and body fat percentage (%BF), were determined. The differences between groups were performed accordingly to normal and non-normal distribution. Spearman's correlations were performed to analyze the hypothetical correlation between KIDMED and BMI. RESULTS: Players reached an average KIDMED score of 8.36 ± 1.92, showing that 68.2% (n = 90) reached high adherence to the MD, 31.1% (n = 41) had moderate adherence to the MD, and 0.78% (n = 1) had poor adherence to the MD. When the analysis was made for age group and BMI classification, no significant differences were observed in adherence to the MD. Considering the main characteristics of the MD, 50.8% consumed fruit (vs. 49,2%), 52.3% consumed vegetables (vs. 47,7%), and only 20% consumed oleaginous dried fruits (vs. 80%). Dairy consumption throughout the day was 49,2% (vs. no: 50,8%). CONCLUSION: Data from the present study showed that many soccer players adhered to the MD, and no differences were observed for age group or BMI classification.
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Marine-origin gelatin has been increasingly used as a safe alternative to bovine and porcine ones due to their structural similarity, avoiding the health-related problems and sociocultural concerns associated with using mammalian-origin materials. Another benefit of marine-origin gelatin is that it can be produced from fish processing-products enabling high production at low cost. Recent studies have demonstrated the excellent capacity of gelatin-methacryloyl (GelMA)-based hydrogels in a wide range of biomedical applications due to their suitable biological properties and tunable physical characteristics, such as tissue engineering applications, including the engineering of cartilage. In this study, fish gelatin was obtained from Greenland halibut skins by an acidic extraction method and further functionalized by methacrylation using methacrylic anhydride, developing a photosensitive gelatin-methacryloyl (GelMA) with a degree of functionalization of 58%. The produced marine GelMA allowed the fabrication of photo-crosslinked hydrogels by incorporating a photoinitiator and UV light exposure. To improve the biological performance, GelMA was combined with two glycosaminoglycans (GAGs): hyaluronic acid (HA) and chondroitin sulfate (CS). GAGs methacrylation reaction was necessary, rendering methacrylated HA (HAMA) and methacrylated CS (CSMA). Three different concentrations of GelMA were combined with CSMA and HAMA at different ratios to produce biomechanically stable hydrogels with tunable physicochemical features. The 20% (w/v) GelMA-based hydrogels produced in this work were tested as a matrix for chondrocyte culture for cartilage tissue engineering with formulations containing both HAMA and CSMA showing improved cell viability. The obtained results suggest these hybrid hydrogels be used as promising biomaterials for cartilage tissue engineering applications.
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The teaching hospital of the Faculty of Veterinary Medicine at the University of Lisbon hosts a Biological Isolation and Containment Unit (BICU) for the hospitalization of both confirmed and suspected animals of an infectious disease. This study targets the BICU dog population to identify and characterize the most frequent infectious diseases recorded in a 7-year period. Several epidemiologic factors were analyzed for their significance to triage infected cases. During the study period, 534 dogs were admitted, of which 263 (49.3%) had a confirmed infectious disease diagnosis: parvovirosis (49.4%; n = 130); leptospirosis (21.7%; n = 57); multidrug-resistant (MDR) bacterial infection; (10.6%; n = 28), and canine distemper (9.9%; n = 26). Several potential risk factors for these diseases were identified: age under 2 years old (p < 0.001), incomplete vaccination for parvovirosis (p < 0.001), age ≥ 10 years old (p < 0.001), and the presence of concomitant disorders for MDR-infected cases (p = 0.03). Logistic regression models were constructed to classify cases and controls. The sensitivity and specificity estimates were very high (>0.83) for parvovirosis, MDR, and distemper infections. A lower sensitivity (0.77) was obtained for identifying cases with leptospirosis. In conclusion, infectious diseases are frequent, hence, it is essential to decrease their occurrence through effective preventive measures such as vaccination. The constructed logistic models can also help in triaging admitted dogs with a potential infectious disease.
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Introduction: Upper tarsal mechanical forces influence corneal epithelial thickness profile, which could modulate corneal astigmatism. Upper eyelid blepharoplasty reduces upper tarsal strength and may have an impact on ocular surface. The aim of this study is to evaluate the effect of upper eyelid blepharoplasty on corneal epithelial thickness profile, astigmatism and aberrations. Methods: Patients with dermatochalasis underwent bilateral upper eyelid blepharoplasty. Anterior segment optical coherence tomography (AS-OCT) (Zeiss Cirrus 5000 HD-OCT) and Pentacam (Oculus, Wetzlar Germany) were performed before surgery and in the 8th postoperative week. Corneal epithelial thickness, keratometry, aberrations and asphericity were considered for statistical purposes. Only right eyes were considered. A p-value lower than 0.05 was considered significant. Results: Thirty eyes of 30 patients were included. The degree of astigmatism did not change after surgery (0.95D vs 0.83D, p=0.23). The difference between preoperative and postoperative steepest axis was 3.1° (p=0.04) with a tendency to change toward the vertical meridian. Mean epithelial thickness was higher in the inferior region both pre- and postoperatively and did not change. ET in the superior octant was lower (42 µm vs 45 µm, p<0.01) and the difference between inferior and superior octants (I-S) was higher (7 µm vs 3 µm, p<0.001) before surgery. There were no statistically significant changes in corneal aberrations (p=0.52) and asphericity (p=0.41) after surgery. Conclusion: Our results support that upper tarsus pressure influences epithelial thickness profile and, consequently, the corneal steepest keratometry. These results lead us to postulate that upper eyelid blepharoplasty may influence biometric and keratometric measurements.
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Corneal pathologies from infectious or noninfectious origin have a significant impact on the daily lives of millions of people worldwide. Despite the risk of organ rejection or infection, corneal transplantation is currently the only effective treatment. Finding safe and innovative strategies is the main goal of tissue-engineering-based approaches. In this study, the potential of gelatin methacryloyl (GelMA) hydrogels produced from marine-derived gelatin and loaded with ascorbic acid (as an enhancer of the biological activity of cells) was evaluated for corneal stromal applications. Marine GelMA was synthesized with a methacrylation degree of 75%, enabling effective photocrosslinking, and hydrogels with or without ascorbic acid were produced, encompassing human keratocytes. All the produced formulations exhibited excellent optical and swelling properties with easy handling as well as structural stability and adequate degradation rates that may allow proper extracellular matrix remodeling by corneal stromal cells. Formulations loaded with 0.5 mg/mL of ascorbic acid enhanced the biological performance of keratocytes and induced collagen production. These results suggest that, in addition to marine-derived gelatin being suitable for the synthesis of GelMA, the hydrogels produced are promising biomaterials for corneal regeneration applications.
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Purpose: To evaluate the changes on epithelial thickness before and after topical treatment in primary Sjögren syndrome-associated dry eye disease (SS-DED). Methods: This was a prospective study that included referred women with SS-DED and healthy age-matched controls. Corneal epithelial thickness was evaluated using high-definition anterior segment optical coherence tomography (Cirrus 5000 HD-OCT) in the baseline first consultation, and four weeks after treatment with preservative free 1mg/1mL sodium hyaluronate. Schirmer test 1 (ST1), tear break-up time (TBUT), tear meniscus height (TMH), SICCA Ocular Surface Score (SICCA OSS) and Ocular Surface Disease Index (OSDI) were evaluated. Statistical significance was defined as p-value <0.05. Results: The study included 40 eyes, 20 with SS-DED and 20 controls. At baseline, SS-DED patients had lower ST1 (11.1 ± 2.2mm vs 14.1 ± 3.1mm, p<0.01), faster TBUT (9.1 ± 1.8s vs 13.2 ± 1.1s, p<0.01) and lower TMH (211.2 ± 68.4 µm vs 217.2 ± 60.1µm; p<0.01) than the control group, whereas SICCA OSS and OSDI were higher (p<0.01). The superior epithelium was thinner in SS-DED group (41.1 ± 3.2 µm vs 43.1± 2.3 µm, p<0.01). After treatment, ST1, TBUT, TMH, SICCA OSS, and OSDI improved (p<0.01), and superior epithelium thickened (p<0.01) in the SS-DED group. Conclusion: Treatment with sodium hyaluronate improved ST1, TBUT, TMH, SICCA-OSS, and OSDI score. Superior epithelium tends to be thinner in SS-DED but becomes thicker with treatment. Our results seem to illustrate the morphological changes in the corneal epithelium in DED, which could be further recognized as a clinical biomarker of SS-DED.
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PURPOSE: To assess the clinical outcomes and patient satisfaction of the Tecnis Eyhance, an advanced monofocal intraocular lens (IOL), compared to a conventional monofocal IOL. DESIGN: Retrospective case-control study. METHODS: This study included 120 eyes of 60 patients (30 patients in each group) who underwent bilateral cataract surgery either with the implantation of conventional monofocal IOLs (Tecnis PCB00), as a control group, or advanced monofocal IOLs (Tecnis Eyhance ICB00). Ophthalmological evaluation included the measurement of binocular corrected distance visual acuity (CDVA), monocular and binocular uncorrected distance visual acuity (UDVA), and uncorrected intermediate VA (UIVA). In addition the binocular defocus curve was analyzed. Furthermore a subjective questionnaire (Catquest-9SF) was used to assess vision and life quality. RESULTS: The average binocular UDVA was 20/22 in the ICB00 group and 20/20 in the PCB00 model (p = 0.62). The average monocular UIVA was 20/32 in the ICB00 group and 20/40 in the control group (p < 0.001). We found the binocular UIVA, had a mean value of 20/30 in the ICB00, compared to 20/40 in the control group (p < 0.001). The reported dysphotopsia was not significantly different between both groups (p = 0.56). Regarding the life quality questionnaire, the ICB00 group showed less difficulty in activities requiring intermediate vision. CONCLUSION: Our results demonstrated a significant improvement in visual acuity for intermediate distance in the ICB00 group compared to the control group, without compromising distance visual acuity. We also found a greater capability for intermediate distance activities (namely for computer use and reading price tags) when comparing ICB00 patients with the control group.
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Lentes Intraoculares , Facoemulsificação , Estudos de Casos e Controles , Humanos , Implante de Lente Intraocular , Satisfação do Paciente , Desenho de Prótese , Refração Ocular , Estudos Retrospectivos , Visão BinocularRESUMO
PURPOSE: Our aim was to assess ocular surface and tear film stability and corneal epithelial thickness (CET) in patients with Graves disease (GD) with and without Graves orbitopathy (GO). METHODS: This study included healthy age-matched controls and patients with GD. Symptoms (Ocular Surface Disease Index questionnaire) and signs (schirmer test and tear breakup time test) of dry eye disease were determined, according to the International Dry Eye Workshop II criteria of DED. CET map was also assessed. RESULTS: Twenty-four eyes were included in the control group, with a mean age of 41.00 ± 13.65 years, and 34 in the GD group, 18 with GO and 16 without GO, with a mean age of 44.44 ± 13.95 and 45.75 ± 10.59 years, respectively. All patients with GO had inactive disease (mean clinical activity score: 1.33 ± 0.69). Patients with GD had higher proportion of clinical diagnosis of dry eye disease (GO vs. GD without GO vs. controls: 77.77% vs. 75.00% vs. 4.17%), with higher Ocular Surface Disease Index (GO vs. GD without GO vs. controls: 15.44 vs. 15.06 vs. 9.88) and lower tear breakup time test (GO vs. GD without GO vs. controls: 6.33 s vs. 7.25 s vs. 11.63 s). Superior CET was lower in patients with GD (P < 0.05). No differences were found between patients with and without GO (P > 0.05). CONCLUSIONS: GD negatively influenced ocular surface and CET, with a higher level of eye dryness and corneal thinning regardless of GO status, suggesting that subclinical chronic inflammation may play a role in the pathogenesis of tear film and ocular surface stability.
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Síndromes do Olho Seco/fisiopatologia , Epitélio Corneano/patologia , Doença de Graves/fisiopatologia , Oftalmopatia de Graves/fisiopatologia , Lágrimas/fisiologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos e QuestionáriosRESUMO
Purpose: To evaluate the effect of eye rubbing on the epithelial thickness profile in tomographically normal corneas by AS-OCT and to compare right and left eyes in right-handed children. Methods: Thirty right-handed boys (mean age 11.2 years) with ocular allergy and history of eye rubbing were evaluated using Scheimpflug (Pentacam HR, Oculus Wetzlar, Germany) and anterior segment optical coherence tomography. Epithelial thickness (ET) and full corneal thickness (CT) parameters were compared between right and left eyes with a non-parametric Mann-Whitney test. A p-value lower than 0.05 was considered for statistical significance. Results: No eyes had topometric nor tomographic criteria for keratoconus. The min-max ET was lower in right eyes (-2.8 µm vs -3.5; p = 0.02). The difference between inferior and superior (I-S) octants was lower in right eyes (1.1 µm vs 1.9 µm; p = 0.03) as a result of inferotemporal thinning. The highest ET difference was registered between nasal and temporal octants and was more pronounced in the right eyes (2 µm vs 3.1 µm; p < 0.001). Conclusion: AS-OCT analyses reveal different epithelial thickness patterns between the eyes in young atopic patients, likely eye rubbers. Inferior and temporal epithelial thickness seem to be more affected by thinning in the eye on the side of the dominant hand.
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BACKGROUND: Referral of cases is becoming more and more frequent in companion animal practice. The Infectious Diseases Isolation Unit (IDIU) admits first opinion, second opinion and referred patients with a confirmed infectious disease (ID) or a clinically suspected ID that is awaiting laboratory diagnosis. The primary aims of this study were to describe the annual number and characteristics of patients referred to the IDIU and identify the most frequent IDs in referred dogs and cats. A secondary aim was to investigate possible differences in the length of the hospitalisation and the clinical outcome among referred cases and those admitted to the IDIU after first and second opinion appointments. METHODS: A retrospective study was carried out on patients hospitalised at the unit over 5 years from 9th October 2013 to 31st December 2018. RESULTS: The study population consisted of 365 dogs and 515 cats to give a total of 880 patients hospitalised at the IDIU from October 2013 to December 2018. Among the 96 referred dogs, parvovirosis (37.7%) and leptospirosis (31.1%) were the most frequent IDs. Feline upper respiratory tract infection (38.2%) and feline leukaemia virus infections (36.4%) were the main causes in the 80 referred cats. Worrying noncompliance rates of dog (51.0%) and cat (52.5%) vaccination schedules were identified. The analysis of the length of hospitalisation in the three groups of patients was not statistically different. In both animal species there were statistically significant higher clinical discharge rates on the first opinion patients' group in comparison to referred patients and the second opinion group. CONCLUSIONS: Parvovirosis and leptospirosis in dogs and upper respiratory disease and feline leukaemia virus infection in cats were the most common diagnoses for patients admitted to the IDIU, reinforcing the need for accurate vaccination. Discharge rates results pinpoint the need for timely accurate reference.
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PURPOSE: To assess the preliminary clinical outcomes and patient satisfaction of the new enhanced depth of focus (EDOF) LuxSmart™ intraocular lens IOL and to compare with a conventional monofocal IOL (Akreos™) in patients who had undergone bilateral cataract surgery. METHODS: Twelve patients underwent bilateral LuxSmart IOL implantation, and twelve underwent bilateral Akreos IOL implantation. Best-corrected distance (CDVA) and uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA) at 66cm, uncorrected near visual acuity (UNVA) at 40cm and defocus curve were assessed. Patients-reported visual function was inquired by Catquest-9SF. The presence of photic phenomena was evaluated. A p-value lower than 0.05 was considered for statistical significance. RESULTS: The mean IOL power was +21.90D in LuxSmart group and +22.30D in Akreos. Monocular UDVA (p = 0.32) and CDVA (p = 0.52) did not differ between groups. The average binocular UIVA (0.18 ± 0.12 logMAR vs. 0.30 ± 0.13 logMAR, p < 0.001) and UNVA (0.38 ± 0.14 logMAR vs. 0.44 ± 0.17 logMAR, p = 0.02) were higher in LuxSmart IOL group. No patients reported disabling photic phenomena in either group. CONCLUSION: This study shows that new LuxSmart EDOF IOL achieved higher performance for intermediate and near vision compared with a conventional monofocal IOL, without increasing the risk of dysphotopsias. LuxSmart may be an attractive and safe option for patients who desire spectacle independence for distance and intermediate vision after cataract surgery.
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PURPOSE: Brain shift during tumor resection can progressively invalidate the accuracy of neuronavigation systems and affect neurosurgeons' ability to achieve optimal resections. This paper compares two methods that have been presented in the literature to compensate for brain shift: a thin-plate spline deformation model and a finite element method (FEM). For this comparison, both methods are driven by identical sparse data. Specifically, both methods are driven by displacements between automatically detected and matched feature points from intraoperative 3D ultrasound (iUS). Both methods have been shown to be fast enough for intraoperative brain shift correction (Machado et al. in Int J Comput Assist Radiol Surg 13(10):1525-1538, 2018; Luo et al. in J Med Imaging (Bellingham) 4(3):035003, 2017). However, the spline method requires no preprocessing and ignores physical properties of the brain while the FEM method requires significant preprocessing and incorporates patient-specific physical and geometric constraints. The goal of this work was to explore the relative merits of these methods on recent clinical data. METHODS: Data acquired during 19 sequential tumor resections in Brigham and Women's Hospital's Advanced Multi-modal Image-Guided Operating Suite between December 2017 and October 2018 were considered for this retrospective study. Of these, 15 cases and a total of 24 iUS to iUS image pairs met inclusion requirements. Automatic feature detection (Machado et al. in Int J Comput Assist Radiol Surg 13(10):1525-1538, 2018) was used to detect and match features in each pair of iUS images. Displacements between matched features were then used to drive both the spline model and the FEM method to compensate for brain shift between image acquisitions. The accuracies of the resultant deformation models were measured by comparing the displacements of manually identified landmarks before and after deformation. RESULTS: The mean initial subcortical registration error between preoperative MRI and the first iUS image averaged 5.3 ± 0.75 mm. The mean subcortical brain shift, measured using displacements between manually identified landmarks in pairs of iUS images, was 2.5 ± 1.3 mm. Our results showed that FEM was able to reduce subcortical registration error by a small but statistically significant amount (from 2.46 to 2.02 mm). A large variability in the results of the spline method prevented us from demonstrating either a statistically significant reduction in subcortical registration error after applying the spline method or a statistically significant difference between the results of the two methods. CONCLUSIONS: In this study, we observed less subcortical brain shift than has previously been reported in the literature (Frisken et al., in: Miller (ed) Biomechanics of the brain, Springer, Cham, 2019). This may be due to the fact that we separated out the initial misregistration between preoperative MRI and the first iUS image from our brain shift measurements or it may be due to modern neurosurgical practices designed to reduce brain shift, including reduced craniotomy sizes and better control of intracranial pressure with the use of mannitol and other medications. It appears that the FEM method and its use of geometric and biomechanical constraints provided more consistent brain shift correction and better correction farther from the driving feature displacements than the simple spline model. The spline-based method was simpler and tended to give better results for small deformations. However, large variability in the spline results and relatively small brain shift prevented this study from demonstrating a statistically significant difference between the results of the two methods.
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Neoplasias Encefálicas/cirurgia , Imageamento Tridimensional/métodos , Imageamento por Ressonância Magnética/métodos , Neuronavegação/métodos , Procedimentos Neurocirúrgicos/métodos , Neoplasias Encefálicas/diagnóstico , Análise de Elementos Finitos , Humanos , Estudos Retrospectivos , Ultrassonografia/métodosRESUMO
In brain tumor surgery, the quality and safety of the procedure can be impacted by intra-operative tissue deformation, called brain shift. Brain shift can move the surgical targets and other vital structures such as blood vessels, thus invalidating the pre-surgical plan. Intra-operative ultrasound (iUS) is a convenient and cost-effective imaging tool to track brain shift and tumor resection. Accurate image registration techniques that update pre-surgical MRI based on iUS are crucial but challenging. The MICCAI Challenge 2018 for Correction of Brain shift with Intra-Operative UltraSound (CuRIOUS2018) provided a public platform to benchmark MRI-iUS registration algorithms on newly released clinical datasets. In this work, we present the data, setup, evaluation, and results of CuRIOUS 2018, which received 6 fully automated algorithms from leading academic and industrial research groups. All algorithms were first trained with the public RESECT database, and then ranked based on a test dataset of 10 additional cases with identical data curation and annotation protocols as the RESECT database. The article compares the results of all participating teams and discusses the insights gained from the challenge, as well as future work.
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Algoritmos , Encéfalo/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Procedimentos Neurocirúrgicos/métodos , Cirurgia Assistida por Computador/métodos , Ultrassonografia/métodos , Encéfalo/cirurgia , Neoplasias Encefálicas/diagnóstico por imagem , Bases de Dados Factuais , Glioma/diagnóstico por imagem , Glioma/cirurgia , HumanosRESUMO
OBJECTIVE: Neuronavigation procedures demand high precision and accuracy. Despite this need, there are still few studies analyzing errors in such procedures. The aim of this study was to use a custom-built cranial phantom to measure target position and orientation errors in different phases of a simulated neuronavigation procedure. METHODS: A cranial phantom with 10 target sites was designed and imaged with computed tomography and magnetic resonance. A segmentation of a cloud of points of the phantom (ground truth) was obtained using an optical tracking system and compared with the images (imaging phase). Targets and trajectories were then planned with neuronavigation software and compared with the ground truth (planning phase). The same plan was used to identify the points in real space after image-to-phantom registration and calculate the final error of the procedure by comparison with the ground truth (registration and execution phase). RESULTS: The mean errors after the imaging phase were 1.11 ± 0.42 mm and 3.23° ± 1.69° for position and orientation, respectively. After planning the mean errors were 1.10 ± 0.39 mm and 5.55° ± 2.91°. The global errors after the registration and mechanical execution were 3.93 ± 1.70 mm and 3.65° ± 1.29°. CONCLUSIONS: After a stepwise analysis, registration and mechanical execution were the main contributors to the global position error.