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Alanazi R, Esporcatte LPG, White L, Salomão MQ, Lopes BT, Ambrósio R, Abass A. Investigation of How Corneal Densitometry Artefacts Affect the Imaging of Normal and Keratoconic Corneas. Bioengineering (Basel) 2024; 11:148. [PMID: 38391634 PMCID: PMC10886353 DOI: 10.3390/bioengineering11020148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Revised: 01/27/2024] [Accepted: 01/29/2024] [Indexed: 02/24/2024] Open
Abstract
PURPOSE To investigate corneal densitometry artefacts found in Pentacam Scheimpflug scans and their potential effect on assessing keratoconic (KC) corneas compared to normal (N) corneas. METHODS The current study utilises Pentacam data of 458 N eyes, aged 35.6 ± 15.8 (range 10-87), referred to as the "N group", and 314 KC eyes, aged 31.6 ± 10.8 (range 10-72), referred to as the "KC group", where densitometry data were extracted and analysed via a custom-built MATLAB code. Radial summations of the densitometry were calculated at diameters ranging from 0.5 mm to 5.0 mm. The minimum normalised radial summation of densitometry (NRSD) value and angle were determined at each diameter and then linked. KC cone locations and areas of pathology were determined, and a comparison between N and KC groups was carried out both within the averaged area of pathology and over the corneal surface. RESULTS Joining minimum NRSD trajectory points marked a clear distortion line pointing to the nasal-superior direction at 65° from the nasal meridian. The findings were found to be independent of eye laterality or ocular condition. Consistency was detected in the right and left eyes among both the N and KC groups. The location of the KC cone centre and the area of pathology were determined, and the densitometry output was compared both within the area of pathology and over the whole cornea. When the average densitometry was compared between N and KC eyes within the KC area of pathology, the N group recorded a 16.37 ± 3.15 normalised grey-scale unit (NGSU), and the KC group recorded 17.74 ± 3.4 NGSU (p = 0.0001). However, when the whole cornea was considered, the N group recorded 16.71 ± 5.5 NGSU, and the KC group recorded 15.72 ± 3.98 NGSU (p = 0.0467). A weak correlation was found between the Bad D index and NGSU when the whole measured cornea was considered (R = -0.01); however, a better correlation was recorded within the KC area of pathology (R = 0.21). CONCLUSIONS Nasal-superior artefacts are observed in the densitometry Pentacam maps, and analysis shows no significant differences in their appearance between N or KC corneas. When analysing KC corneas, it was found that the cone positions are mostly on the temporal-inferior side of the cornea, opposite to the densitometry artefact NRSD trajectory. The analysis suggests that the corneal densitometry artefacts do not interfere with the KC area of pathology as it reaches its extreme in the opposite direction; therefore, weighting the densitometry map to increase the contribution of the inferior-temporal cornea and decreasing that of the superior-nasal area would improve the classification or identification of KC if densitometry is to be used as a KC metric.
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Affiliation(s)
- Rami Alanazi
- Department of Materials, Design and Manufacturing Engineering, School of Engineering, University of Liverpool, Liverpool L69 3GH, UK
| | - Louise Pellegrino Gomes Esporcatte
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro 20520-050, Brazil
- Instituto de Olhos Renato Ambrósio, Rio de Janeiro 20520-050, Brazil
- Department of Ophthalmology, Federal University of São Paulo, São Paulo 04017-030, Brazil
| | - Lynn White
- Research and Development Department, LWVision, Leicester LE18 1DF, UK
| | - Marcella Q Salomão
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro 20520-050, Brazil
- Instituto de Olhos Renato Ambrósio, Rio de Janeiro 20520-050, Brazil
- Department of Ophthalmology, Federal University of São Paulo, São Paulo 04017-030, Brazil
- Instituto Benjamin Constant, Rio de Janeiro 22290-255, Brazil
| | - Bernardo T Lopes
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro 20520-050, Brazil
- Department of Ophthalmology, Federal University of São Paulo, São Paulo 04017-030, Brazil
- Ophthalmology Eye Clinic, Alder Hey Children's NHS Foundation Trust, Liverpool L12 2AP, UK
| | - Renato Ambrósio
- Instituto de Olhos Renato Ambrósio, Rio de Janeiro 20520-050, Brazil
- Department of Ophthalmology, Federal University of São Paulo, São Paulo 04017-030, Brazil
- Department of Ophthalmology, Federal University the State of Rio de Janeiro, Rio de Janeiro 22290-240, Brazil
- Brazilian Study Group of Artificial Intelligence and Corneal Analysis-BrAIN, Rio de Janeiro & Maceió, Rio de Janeiro 20520-050, Brazil
| | - Ahmed Abass
- Department of Materials, Design and Manufacturing Engineering, School of Engineering, University of Liverpool, Liverpool L69 3GH, UK
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Pathological characteristics of light chain crystalline podocytopathy. Kidney Int 2023; 103:616-626. [PMID: 36581019 DOI: 10.1016/j.kint.2022.11.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/14/2022] [Accepted: 11/17/2022] [Indexed: 12/28/2022]
Abstract
Monoclonal immunoglobulin light chain (LC) crystalline inclusions within podocytes are rare, poorly characterized entities. To provide more insight, we now present the first clinicopathologic series of LC crystalline podocytopathy (LCCP) encompassing 25 patients (68% male, median age 56 years). Most (80%) patients presented with proteinuria and chronic kidney disease, with nephrotic syndrome in 28%. Crystalline keratopathy and Fanconi syndrome were present in 22% and 10%, respectively. The hematologic condition was monoclonal gammopathy of renal significance (MGRS) in 55% and multiple myeloma in 45%. The serum monoclonal immunoglobulin was IgG κappa in 86%. Histologically, 60% exhibited focal segmental glomerulosclerosis (FSGS), often collapsing. Ultrastructurally, podocyte LC crystals were numerous with variable effacement of foot processes. Crystals were also present in proximal tubular cells as light chain proximal tubulopathy (LCPT) in 80% and in interstitial histiocytes in 36%. Significantly, frozen-section immunofluorescence failed to reveal the LC composition of crystals in 88%, requiring paraffin-immunofluorescence or immunohistochemistry, with identification of kappa LC in 87%. The LC variable region gene segment, determined by mass spectrometry of glomeruli or bone marrow plasma cell sequencing, was IGKV1-33 in four and IGKV3-20 in one. Among 21 patients who received anti-plasma cell-directed chemotherapy, 50% achieved a kidney response, which depended on a deep hematologic response. After a median follow-up of 36 months, 26% progressed to kidney failure and 17% died. The mean kidney failure-free survival was 57.6 months and was worse in those with FSGS. In sum, LCCP is rare, mostly associates with IgG κappa MGRS, and frequently has concurrent LCPT, although Fanconi syndrome is uncommon. Paraffin-immunofluorescence and electron microscopy are essential to prevent misdiagnosis as primary FSGS since kidney survival depends on early diagnosis and subsequent clone-directed therapy.
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Consejo A, Jiménez-García M, Rozema JJ, Abass A. Influence of eye tilt on corneal densitometry. Ophthalmic Physiol Opt 2022; 42:1032-1037. [PMID: 35708180 PMCID: PMC9543421 DOI: 10.1111/opo.13020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 05/24/2022] [Accepted: 05/24/2022] [Indexed: 11/24/2022]
Abstract
PURPOSE To investigate whether Pentacam densitometry readings are affected by corneal tilt. METHODS In a prospective study, the right eyes of 86 healthy participants aged 42.8 ± 20.0 years (range 18-79 years) were imaged using Scheimpflug tomography. Elevation maps were exported to calculate corneal tilt using custom-made software, and densitometry readings were acquired directly from the corneal densitometry analysis add-on to the standard software Oculus Pentacam HR. Simple mediation analysis was applied to study age as a confounding factor in the correlation between corneal tilt and corneal densitometry. RESULTS Corneal tilt and corneal densitometry are not independent from one another because age is significantly correlated with both corneal tilt (r = 0.50, p < 0.001) and corneal densitometry (r = 0.91, p < 0.001). Only 3.8% of the correlation between tilt and densitometry operates directly, while the remaining 96.2% depends on age. CONCLUSIONS Corneal tilt plays a role in corneal densitometry readings, even though the interaction is strongly influenced by age. Age is a well-known factor in densitometry readings that should be taken into consideration when interpreting Scheimpflug densitometry.
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Affiliation(s)
- Alejandra Consejo
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
| | - Marta Jiménez-García
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium.,Visual Optics Lab Antwerp (VOLANTIS), Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Jos J Rozema
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium.,Visual Optics Lab Antwerp (VOLANTIS), Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Ahmed Abass
- Department of Mechanical, Materials and Aerospace Engineering, School of Engineering, University of Liverpool, Liverpool, UK.,Department of Production Engineering and Mechanical Design, Faculty of Engineering, Port Said University, Port Said, Egypt
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Corneal Densitometry and In Vivo Confocal Microscopy in Patients with Monoclonal Gammopathy—Analysis of 130 Eyes of 65 Subjects. J Clin Med 2022; 11:jcm11071848. [PMID: 35407456 PMCID: PMC9000138 DOI: 10.3390/jcm11071848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/19/2022] [Accepted: 03/23/2022] [Indexed: 12/03/2022] Open
Abstract
Background: Corneal imaging may support an early diagnosis of monoclonal gammopathy. The goal of our study was to analyze corneal stromal properties using Pentacam and in vivo confocal cornea microscopy (IVCM) in subjects with monoclonal gammopathy. Patients and methods: In our cross-sectional study, patients with monoclonal gammopathy (130 eyes of 65 patients (40.0% males; age 67.65 ± 9.74 years)) and randomly selected individuals of the same age group, without hematological disease (100 eyes of 50 control subjects (40.0% males; age 60.67 ± 15.06 years)) were included. Using Pentacam (Pentacam HR; Oculus GmbH, Wetzlar, Germany), corneal stromal light scattering values were obtained (1) centrally 0–2 mm zone; (2) 2–6 mm zone; (3) 6–10 mm zone; (4) 10–12 mm zone. Using IVCM with Heidelberg Retina Tomograph with Rostock Cornea Module (Heidelberg Engineering, Heidelberg, Germany), the density of hyperreflective keratocytes and the number of hyperreflective spikes per image were manually analyzed, in the stroma. Results: In the first, second and third annular zone, light scattering was significantly higher in subjects with monoclonal gammopathy, than in controls (p ≤ 0.04). The number of hyperreflective keratocytes and hyperreflective spikes per image was significantly higher in stroma of subjects with monoclonal gammopathy (p ≤ 0.012). Conclusions: Our study confirms that increased corneal light scattering in the central 10 mm annular zone and increased keratocyte hyperreflectivity may give rise to suspicion of monoclonal gammopathy. As corneal light scattering is not increased at the limbal 10–12 mm annular zone in monoclonal gammopathy subjects, our spatial analysis provides evidence against the limbal origin of corneal paraprotein deposition. Using IVCM, stromal hyperreflective spikes may represent specific signs of monoclonal gammopathy.
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Ichii M, Koh S, Maeno S, Busch C, Oie Y, Maeda T, Shibayama H, Nishida K, Kanakura Y. Noninvasive assessment of corneal alterations associated with monoclonal gammopathy. Int J Hematol 2019; 110:500-505. [DOI: 10.1007/s12185-019-02664-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 05/10/2019] [Accepted: 05/14/2019] [Indexed: 11/30/2022]
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