Computer assisted evaluation of retinal vessels tortuosity in Fabry disease

Computer-assisted evaluation of retinal vessel tortuosity in moderate-to-late preterm children

PURPOSE

Since very preterm children often have increased retinal tortuosity that may indicate decisive architectural changes in the systemic microvascular network, we used a new semi-automatic software to measure retinal vessel tortuosity on fundus digital images of moderate-to-late preterm (MLP) children.

METHODS

In this observational case-control study, the global and local tortuosity parameters of retinal vessels were evaluated on fundus photographs of 36 MLP children and 36 age- and sex-matched controls. The associations between birth parameters and parameters reflecting retinal vessel tortuosity were evaluated using correlation analysis.

RESULTS

Even after incorporation of anatomical factors, the global and local tortuosity parameters were not significantly different between groups. The MLP group showed a smaller arteriolar caliber (0.53  ±  0.2) than the controls (0.56  ±  0.2; p  =  0.013). Other local tortuosity parameters, such as vessel length, distance to fovea, and distance to optic disc, were not significantly different between arteries and veins. Tortuosity in both groups was higher among vessels closer to the fovea (r  =  -0.077, p < 0.001) and the optic disc (r  =  -0.0544, p  =  0.009). Global tortuosity showed a weakly positive correlation with gestational age and a weakly negative correlation with birth weight in both groups.

CONCLUSION

MLP patients did not display increased vessel tortuosity in comparison with the controls; however, the arteriolar caliber in the MLP group was smaller than that in children born full-term. Larger studies should confirm this finding and explore associations between cardiovascular and metabolic status and retinal vessel geometry in MLP children.

Assessment of Retinal Vessel Tortuosity Index in Patients with Fabry Disease Using Optical Coherence Tomography Angiography (OCTA)

Vessel tortuosity (VT) is a parameter used to assess retinal involvement in patients affected by systemic diseases such as Fabry disease (FD). In this study, we assessed a retinal VT index (VTI) using optical coherence tomography angiography (OCTA) in a group of patients with FD (FD cohort) compared to a healthy control group (HC cohort). This is a single-center, retrospective study analysis of all consecutive patients with genetically tested and confirmed FD who underwent regular ophthalmological visits from December 2017 to January 2020 at the Department of Ophthalmology at the University Hospital of Zurich, Switzerland. VTI was calculated for each OCTA image and the results were compared between FD and HC cohort. A total of 56 participants, 32 (male:female ratio 12:20) in the FD cohort and 24 (male:female ratio 13:11) in the HC cohort. Classic onset was determined in 18 patients. Overall, mean VTI (±SD) was 0.21 (±0.07). Male patients with classic-onset FD had a significantly higher mean VTI (0.33, SD ± 0.35) compared to all other subgroups (p-value < 0.05). Further investigations of retinal VTI in patients with FD could be helpful to use OCTA as a noninvasive screening and follow-up modality to assess disease progression in affected patients.

Relationship of Vessel Density to Vessel Length Density in Patients with Treated Fabry Disease

BACKGROUND

Fabry disease (FD) is a potentially lethal lysosomal disorder with systemic vascular changes. Previous studies demonstrated retinal vascular involvement using optical coherence tomography angiography (OCTA) in affected patients; Aim: To analyze and quantify the retinal vasculature measuring vessel density (VD), vessel length density (VLD), and the ratio of VD to VLD (VD/VLD) in superficial capillary plexuses (SCP) and deep capillary plexuses (DCP) using OCTA in patients with FD and to show whether they differ from healthy controls (HC); Patients and methods: Single-center, retrospective, consecutive cohort study of patients with genetically proven FD. Patients underwent an ophthalmological examination including OCTA. VD, VLD, foveal avascular zone (FAZ), and the VD/VLD were compared to an HC group using a linear mixed model; Results: A statistically significant difference in the VLD and VD/VLD of DCP was observed between the two groups (p < 0.001). Using ROC curves with AUC and Youden's Index, a cut-off value for differentiating both groups using VD/VLD in DCP FD with high specificity and high sensitivity was established; Conclusions: FD and HC groups seem to be separable using the VD/VLD ratio in DCP. This new biomarker might differentiate changes in the retinal microvasculature that are not detectable by VD or VLD alone.

Retinal biomarkers of Cerebral Small Vessel Disease: A systematic review

INTRODUCTION

Cerebral Small Vessel Disease (CSVD), a progressive degenerative disorder of small caliber cerebral vessels, represents a major contributor to stroke and vascular dementia incidence worldwide. We sought to conduct a systematic review of the role of retinal biomarkers in diagnosis and characterization of CSVD.

METHODS

We conducted a systematic review of MEDLINE, PubMed, Scopus, the Cochrane Library Database, and Web of Science. We identified studies of sporadic CSVD (including CSVD not otherwise specified, Cerebral Amyloid Angiopathy, and Hypertensive Arteriopathy) and the most common familial CSVD disorders (including CADASIL, Fabry disease, and MELAS). Included studies used one or more of the following tools: visual fields assessment, fundus photography, Optical Coherence Tomography and OCT Angiography, Fluorescein Angiography, Electroretinography, and Visual Evoked Potentials.

RESULTS

We identified 48 studies of retinal biomarkers in CSVD, including 9147 cases and 12276 controls. Abnormalities in retinal vessel diameter (11 reports, n = 11391 participants), increased retinal vessel tortuosity (11 reports, n = 617 participants), decreased vessel fractal dimension (5 reports, n = 1597 participants) and decreased retinal nerve fiber layer thickness (5 reports, n = 4509 participants) were the biomarkers most frequently associated with CSVD. We identified no reports conducting longitudinal retinal evaluations of CSVD, or systematically evaluating diagnostic performance.

CONCLUSION

Multiple retinal biomarkers were associated with CSVD or its validated neuroimaging biomarkers. However, existing evidence is limited by several shortcomings, chiefly small sample size and unstandardized approaches to both biomarkers' capture and CSVD characterization. Additional larger studies will be required to definitively determine whether retinal biomarkers could be successfully incorporated in future research efforts and clinical practice.

Retinal vessel tortuosity as a prognostic marker for disease severity in Fabry disease

Purpose

The aim of this case control study was to evaluate the prognostic value of automatically quantified retinal vessel tortuosity from fundus images and vessel density from OCT-A in Fabry disease and to evaluate the correlation of these with systemic disease parameters.

Methods

Automatically quantified perimacular retinal vessel tortuosity (MONA REVA software), acquired by fundus imaging, and perifoveal retinal vessel density, acquired by optic coherence tomography angiography (OCT-A) were compared between 26 FD patients and 26 controls. Gender and FD phenotype were analyzed to the obtained retinovascular data and correlated to the Mainz severity score index (MSSI) and plasma lyso-Gb3.

Results

Automatically quantified retinal vessel tortuosity indices of FD patients were significantly lower, reflecting an increased vessel tortuosity, compared to controls (p = 0.008). Males with a classical phenotype showed significantly lower retinal vessel tortuosity indices compared to males with an oligosymptomatic phenotype and females with a classical or oligosymptomatic phenotype (p < 0.001). The retinal vessel tortuosity index correlated significantly with systemic disease severity parameters [global MSSI (r = − 0.5; p < 0.01), cardiovascular MSSI (r = − 0.5; p < 0.01), lyso-Gb3 (r = − 0.6; p < 0.01)].

Conclusion

We advocate fundus imaging based automatically quantified retinal vessel tortuosity index over OCT-A imaging as it is a quick, non-invasive, easily assessable, objective and reproducible marker.

IN VIVO OBSERVATION OF RETINAL VASCULAR DEPOSITS USING ADAPTIVE OPTICS IMAGING IN FABRY DISEASE

PURPOSE

To report a novel finding in patients with Fabry disease, that is, the observation by adaptive optics ophthalmoscopy of intracellular lipidic deposits in retinal vessels.

METHODS

Observational two-center case series. Eighteen patients with genetically proven Fabry disease underwent flood-illumination adaptive optics ophthalmoscopy imaging (rtx1; Imagine Eyes, Orsay, France) of retinal vessels.

RESULTS

Fourteen patients (78% of all patients; 7 of the 10 women and 7 of the 8 men) showed paravascular punctuate or linear opacities in both eyes. In the least-affected patients, these were seen only in the wall of precapillary arterioles as discrete spots of 5 µm to 10 µm large, whereas in those more severely affected, capillaries and first-order vessels were also involved with diffuse opacification of the wall. These deposits sometime showed a striated pattern, suggesting colocalization with vascular smooth muscle cells.

CONCLUSION

Adaptive optics ophthalmoscopy of retinal vessels may be of interest for patients with Fabry disease, providing noninvasive, gradable evaluation of microvascular involvement.

Optical Coherence Tomography Angiography for the Evaluation of Retinal Vasculature in Fabry Disease: Our Experience and Review of Current Knowledge

Purpose: Optical coherence tomography angiography (OCTA) is a non-invasive and objective tool for the evaluation of the retinal microvascular changes in Fabry disease (FD). We investigated changes in retinal vasculature in FD patients, and the possible correlation with systemic parameters, by using OCTA, and reviewed the current status of literature.

Methods: Thirteen FD patients (eight females, five males, mean age 49.85 ± 14.7 years) were compared with 13 age- and sex-matched healthy controls. OCTA 3 × 3 mm macular scans were performed in all subjects. We evaluated the vessel density and vessel perfusion in distinct macular areas (whole, inner, and outer) of both the superficial capillary plexus (SCP VD and SCP VP) and of the deep capillary plexus (DCP VD and DCP VP). We also evaluated the foveal avascular zone (FAZ) metrics (area, perimeter, and circularity), and correlation between systemic and OCTA parameters. A literature review on the current understanding of OCTA in FD is then presented.

Results: FD patients showed significantly lower SCP VD values in the whole area (17.37 ± 2.08 mm⁻¹ vs. 18.54 ± 1.21 mm⁻¹; p-value 0.022), as well as in the outer area (17.46 ± 2.10 mm⁻¹ vs. 19.08 ± 1.14 mm⁻¹; p-value 0.002), but not in the inner. Even the DCP VD was significantly lower in all the imaged areas: whole (17.75 ± 3.93 mm⁻¹ vs. 19.71 ± 1.20 mm⁻¹; p-value 0.024), outer (18.25 ± 4.17 mm⁻¹ vs. 20.33 ± 1.20 mm⁻¹; p-value 0.023), and inner (19.54 ± 4.17 mm⁻¹ vs. 21.96 ± 1.55 mm⁻¹; p-value 0.011). There were no significant differences in vessel perfusion parameters (both SCP VP and DCP VP ones) and FAZ. No significant correlations were found between the OCTA parameters and systemic parameters (maximal left ventricular wall thickness and glomerular filtration rate) in FD patients.

Conclusions: OCTA can be considered as a promising non-invasive tool, which enables a quantitative evaluation of retinal vascular involvement in FD, despite the varying data reported in literature. Our results support the use of OCTA as an objective tool to evaluate retinal vascular abnormalities in FD. The utility of OCTA in FD needs to be validated by longitudinal studies taking into account the overall progression of the disease.

Globotrioasylsphingosine Levels and Optical Coherence Tomography Angiography in Fabry Disease Patients

Background: To date, there are no studies associating the dried blood spot (DBS) levels of globotrioasylsphingosine (lysoGb3) with quantitative optical coherence tomography angiography (OCTA) parameters in Fabry disease (FD) patients. Here, we aimed to investigate the association between OCTA vessel density (VD), vessel length density (VLD) with DBS lysoGb3. Methods: A retrospective, single center analysis of all consecutive FD patients enrolled at the Department of Ophthalmology of the University Hospital of Zurich from 1 December 2017 to 9 September 2020. An association between VD and VLD detected by OCTA and lysoGb3 was investigated using a linear mixed model. Results: A total of 57 FD patients (23 male, 34 female; 109 eyes) were included. Forty-one patients suffered from the classic phenotype and 16 from the later-onset phenotype. LysoGb3 inversely correlated with VD and VLD in both the superficial (VD: p = 0.034; VLD: p = 0.02) and deep capillary plexus (VD: p = 0.017; VLD: p = 0.018) in the overall FD cohort. Conclusions: Our study shows an association between lysoGb3 and OCTA VD and VLD. This supports the hypothesis that quantitative OCTA parameters might be useful as diagnostic biomarkers for evaluating systemic involvement in FD, and possibly other diseases.

Retinal hyperreflective foci in Fabry disease

Background

Fabry disease (FD) is an X-linked inherited storage disorder caused by deficiency of lysosomal alpha-Galactosidase A. Here we describe new retinal findings in patients with FD assessed by Spectral domain optical coherence tomography (SD-OCT) and their possible clinical relevance.

Methods

54 eyes of 27 FD patients and 54 eyes of 27 control subjects were included. The ophthalmic examination included visual acuity testing, tonometry, slit lamp and fundus examination. SD-OCT imaging of the macula was performed in all subjects. Central retinal thickness and retinal nerve fiber layer analysis were quantified. Vessel tortuosity was obtained by a subjective scoring and mathematically calculated. Inner retinal hyperreflective foci (HRF) were quantified, clinically graded and correlated with a biomarker of Fabry disease (lyso-Gb3).

Results

In comparison to an age-matched control group, a significant amount of HRF was identified in macular SD-OCT images in FD patients. These HRF were localized within the inner retinal layers. Furthermore, lyso-Gb3 levels correlated significantly with the quantitative evaluation of HRF (p < 0,001). In addition, the vessel tortuosity was remarkably increased in FD patients compared to control persons and correlated significantly with lyso-G3 levels (p = 0.005). A further subanalysis revealed significantly higher HRF and vessel tortuosity scores in male patients with the classic FD phenotype.

Conclusions

The observational, cross sectional, comparative study describes novel intraretinal findings in patients with FD. We were able to identify suspicious HRF within the inner retinal layers. These findings were not accompanied by functional limitations, as visual acuity remained unchanged. However, HRF correlated well with lyso-Gb3, a degradation product of the accumulating protein Gb3 and might potentially indicate Gb3 accumulation within the highly metabolic and densely vascularized macula.

Computer-assisted retinal vessel diameter evaluation in Fabry disease

PURPOSE

Fabry disease retinal vascular involvement has been widely reported, with narrowing of the retinal arterioles, dilation and irregularity of the retinal veins, and exaggerated tortuosity of the retinal vessels. We evaluated retinal vessel diameter in Fabry disease, by means of a dedicated software, aiming to provide a quantitative marker of retinal vascular network abnormalities in Fabry disease patients.

MATERIAL AND METHODS

Observational case-control study evaluating different branches of vessels, peripapillary vessels (group A), temporal vascular arcades (group B), and second-order collaterals of the temporal arcades (group C). We obtained the vessel diameters values from eye fundus digital images of eight Fabry disease patients and eight age-sex matched controls, using a semiautomatic software. Mann-Whitney test was used to compare the Fabry disease group versus the control group.

RESULTS

The difference between the average diameters of all the types of vessels considered were significantly smaller in Fabry disease patients compared to healthy controls, resulting in a decrease in size (mm) of 10.9% for group A, 7.8% for group B, and 7.4% for group C. The most evident difference between Fabry disease patients and controls was found in the largest vessels.

CONCLUSION

A computer-assisted analysis of retinal vessel diameter in Fabry disease by means of dedicated software showed narrower retinal arteries in Fabry disease patients than in controls. Our data support the use of semiautomatic assessment of retinal vessel attenuation as an objective and reproducible method to evaluate retinal vascular alterations in Fabry disease, providing a clinical non-invasive tool for early diagnosis and disease monitoring.

Optical Coherence Tomography Angiography Findings in Fabry Disease

BACKGROUND

Fabry disease (FD) is a X-linked recessive lysosomal storage disorder characterized by altered biodegradation of glycosphingolipids. It is a multisystem pathology, also involving ophthalmological systems that show modifications of the vessel wall due to glycosphingolipid deposits. Optical coherence tomography angiography (OCT-A) allows for an objective analysis of retinal microvasculature alterations, evaluating retinal vessel density in macular region.

METHODS

A total of 54 FD patients (34 females, 20 males, mean age 44.1 ± 15.6 years) and 70 controls (36 females, 34 males, mean age 42.3 ± 15.6 years) were included in this study. We evaluated vessel density in different macular areas (whole image, fovea, and parafovea) of both the superficial capillary plexus (SCP) and of the deep capillary plexus (DCP).

RESULTS

In the SCP there was a significantly lower vascular density in patients compared with controls in whole image (49.95 ± 5.17% vs. 51.99 ± 2.52%; p < 0.001), parafovea (52.01 ± 6.69% vs. 54.30 ± 2.61%; p = 0.002), and fovea (22.38 ± 9.01% vs. 29.31 ± 5.84%; p < 0.0001). In the DCP the vessel density was statistically increased in each macular area in patients compared with controls (54.82 ± 8.07% vs. 50.93 ± 5.46%; p = 0.005, 57.76 ± 7.26% vs. 53.59 ± 5.46%; p = 0.0001, and 39.75 ± 8.59% vs. 34.43 ± 8.68%; p < 0.0001 for whole image, parafovea, and fovea, respectively).

CONCLUSION

OCT-A analysis showed that the macular vessel density was significantly reduced in the SCP and increased in the DCP in FD patients compared with controls. These findings, which might be a consequence of the alteration of vascular wall occurring in FD, support the hypothesis that the evaluation of early retinal microvascular network changes could be a useful tool in the clinical evaluation of the disease.

Quantitative Analysis of Conjunctival and Retinal Vessels in Fabry Disease

Fabry Disease (FD) is a rare X-linked lysosomal storage disorder characterized by systemic and ocular involvement. It has been described an increasing in retinal and conjunctival vessel tortuosity and this feature represents an important marker for the disease. Currently, there is not an objective method to measure and quantify this parameter. We tested a new semi-automatic software measuring retinal and conjunctival vessel tortuosity from eye fundus and conjunctival digital images in a group of FD patients. We performed an observational case-control study evaluating three mathematical parameters describing tortuosity (sum of angle metric [SOAM], product of angle distance [PAD], triangular index [I2e]) obtained from fundus and conjunctival pictures of 11 FD patients and 11 age and sex-matched controls. Both eyes were considered. Mann-Whitney test was used to compare the FD group versus the control group and, within the FD group, male versus female patients. Linear regression analysis was performed to evaluate the possible association of retinal and conjunctival vessels tortuosity parameters with age and with specific markers of systemic disease's progression. The tortuosity parameters (SOAM, PAD and I2e) were significantly higher in retinal vessels and in conjunctival nasal vessels in FD patients in comparison with the controls (p=0.003, p=0.002, p=0.001 respectively for retina) (p=0.023, p=0.014, p=0.001 respectively for nasal conjunctiva). No significant association was found between retinal and conjunctival tortuosity parameters and increasing age or systemic involvement markers. Vessel tortuosity represents an important clinical manifestation in FD. A computer-assisted analysis of retinal and conjunctival vasculature demonstrated an increased vessels tortuosity in patients affected by Fabry disease. This non-invasive technique might be useful to help the diagnosis in early stages, to establish disease severity and monitor its progression.

Computer-aided analysis of middle cerebral artery tortuosity: association with aneurysm development

OBJECTIVE

Blood vessel tortuosity may play an important role in the development of vessel abnormalities such as aneurysms. Currently, however, there are no studies analyzing the impact of brain blood vessel tortuosity on the risk of aneurysm formation. Therefore, the authors performed a computer-aided analysis of middle cerebral artery (MCA) tortuosity, especially among patients diagnosed with MCA aneurysms.

METHODS

Anatomy of the MCAs of 54 patients with unruptured MCA aneurysms was retrospectively analyzed, as was that of 54 sex-, age-, and vessel side-matched control patients without MCA aneurysms. From medical records, the authors obtained each patient's medical history including previous and current diseases and medications. For each patient, they calculated the following tortuosity descriptors: relative length (RL), sum of angle metrics (SOAM), triangular index (TI), product of angle distance (PAD), and inflection count metric (ICM).

RESULTS

Patients with an MCA aneurysm had significantly lower RLs (0.75 ± 0.09 vs 0.83 ± 0.08, p < 0.01), SOAMs (0.45 ± 0.10 vs 0.60 ± 0.17, p < 0.01), and PADs (0.34 ± 0.09 vs 0.50 ± 0.17, p < 0.01). They also had significantly higher TIs (0.87 ± 0.04 vs 0.81 ± 0.07, p < 0.01) and ICMs (3.07 ± 1.58 vs 2.26 ± 1.12, p < 0.01). Female patients had significantly higher RLs (0.76 ± 0.11 vs 0.80 ± 0.09, p = 0.03) than male patients.

CONCLUSIONS

Middle cerebral artery aneurysm formation is strongly associated with blood vessel tortuosity parameters, which can potentially be used to screen for patients at risk for MCA aneurysm formation.

COMPUTER ASSISTED RETINAL VESSEL TORTUOSITY EVALUATION IN NOVEL MUTATION FABRY DISEASE: Towards New Prognostic Markers

PURPOSE

Fabry disease is a rare lysosomal storage disorder with systemic involvement. The authors report on a large Fabry family with GLA p.M187R mutation and exhaustive ophthalmologic assessment.

METHODS

Comprehensive systemic evaluation and genetic diagnosis were performed. Ophthalmologic evaluation included intraocular pressure/visual acuity measurement, refractometry, slit lamp examination, retinography, and optical coherence tomography. Three parameters quantified retinal vessel tortuosity: sum of angle metrics, product of angle distance, and triangular index. Calculations were semiautomatized using dedicated software.

RESULTS

Ten individuals (2 males and 8 females) were described. Seventy-five percent had retinal vessel tortuosity. One hundred percent had cornea verticillata. Perimacular vessels were predominantly involved. The correlation between the right and left eye tortuosity measurements was very tight. A significant correlation between retinal vessel tortuosity and systemic severity measured by general Mainz Severity Score Index (MSSI), renal MSSI, and neurological MSSI but no cardiac MSSI was observed. Right sum of angle metrics value was an independent statistical predictor of the general-MSSI score in presence of age.

CONCLUSION

p.M187R mutation causes a severe systemic and ophthalmologic phenotype, in both male and female patients. Semiautomatic assessment of retinal vessel tortuosity is an objective and reproducible tool. All three parameters of tortuosity are closely associated with Fabry severity scores. Studies of larger series are being awaited to establish the role of retinal vessel tortuosity as a noninvasive marker of disease progression.

The Novel Evidenced Assessment of Tortuosity system: interobserver reliability and agreement with clinical assessment

PURPOSE

Computer-assisted assessment of vessel tortuosity is clinically useful in retinopathy of prematurity (ROP). However, poor image quality is often prohibitive for accurate segmentation by fully automated systems and semi-automated systems are prone to unreliability. In the present work, we describe a method of retinal vessel tortuosity measurement by means of purpose-built image analysis software that does not require high image quality yet is also reliable.

METHODS

Images were obtained from neonates at risk of ROP with Retcam Shuttle(®) . Individual vessels were assessed with the semi-automated Novel Evidenced Assessment of Tortuosity (NEAT) system by two masked experimenters. Scores were compared to assess reliability. They were also compared against clinical scoring of individual vessels by two ROP screeners to assess relationship with clinical assessment. In a second image cohort, the mean of the most tortuous vessel in each of four quadrants in each eye (NEAT-O) was compared against the documented gold standard clinical grading of plus disease.

RESULTS

Reliability of the NEAT system for 50 individual vessels using Bland-Altman plots was excellent. NEAT tortuosity scores for 50 individual vessels compared to clinical scoring showed strong correlation (0.706). Correlation between the NEAT-O score for average tortuosity and gold standard for 167 eyes was modest (0.578).

CONCLUSIONS

The NEAT system is intuitive, user-friendly and robust enough to be clinically useful in poor-quality images. It allows for a rapid, valid and reliable assessment of tortuosity of individual vessels and produces a tortuosity score that correlates well with severity of plus disease.

Fabry in the older patient: Clinical consequences and possibilities for treatment

Baseline demographic and phenotypic characteristics of patients aged ≥50years in the Fabry Outcome Survey (Shire; data extracted June 2014) were compared with younger adults to investigate potential factors influencing treatment decisions in later life. Age groups were defined using age at treatment initiation or at FOS entry for untreated patients: 18-49 (n=1344; 49.5% male; 64.6% received agalsidase alfa enzyme replacement therapy [ERT]); 50-64 (n=537; 35.4% male; 74.3% treated); 65-74 (n=137; 32.1% male; 68.6% treated); and ≥75years (n=26; 26.9% male; 50.0% treated). Successive age groups showed higher median age at first symptom and diagnosis. Median alpha-galactosidase A activity, measured as percentage activity of the midpoint of the normal range, was much greater in females than males of all groups except ≥75years (33.4% in females; 27.8% in males). Patients aged ≥75years showed greater values than patients aged 18-49years for median left ventricular mass indexed to height (62.7 vs 42.4g/m(2.7)), mean ventricular wall thickness (15.0 vs 10.0mm) and prevalence of hypertension (57.7% vs 21.8%), and lower median estimated glomerular filtration rate (Modification of Diet in Renal Disease: 65.6 vs 98.5mL/min/1.73m(2)). Larger proportions in the groups aged ≥50 exhibited cardiac and/or cerebrovascular manifestations compared with patients aged 18-49years. The smaller proportion of patients receiving ERT aged ≥75years compared with the younger groups might reflect relatively milder disease burden or physician/patient reluctance to initiate/continue ERT at this age. Further studies are needed to increase knowledge of Fabry disease and ERT in later life.

Quantification of Microvascular Tortuosity during Tumor Evolution Using Acoustic Angiography

The recent design of ultra-broadband, multifrequency ultrasound transducers has enabled high-sensitivity, high-resolution contrast imaging, with very efficient suppression of tissue background using a technique called acoustic angiography. Here we perform the first application of acoustic angiography to evolving tumors in mice predisposed to develop mammary carcinoma, with the intent of visualizing and quantifying angiogenesis progression associated with tumor growth. Metrics compared include vascular density and two measures of vessel tortuosity quantified from segmentations of vessels traversing and surrounding 24 tumors and abdominal vessels from control mice. Quantitative morphologic analysis of tumor vessels revealed significantly increased vascular tortuosity abnormalities associated with tumor growth, with the distance metric elevated approximately 14% and the sum of angles metric increased 60% in tumor vessels versus controls. Future applications of this imaging approach may provide clinicians with a new tool in tumor detection, differentiation or evaluation, though with limited depth of penetration using the current configuration.

Quantification of tortuosity and fractal dimension of the lung vessels in pulmonary hypertension patients

Pulmonary hypertension (PH) can result in vascular pruning and increased tortuosity of the blood vessels. In this study we examined whether automatic extraction of lung vessels from contrast-enhanced thoracic computed tomography (CT) scans and calculation of tortuosity as well as 3D fractal dimension of the segmented lung vessels results in measures associated with PH.

In this pilot study, 24 patients (18 with and 6 without PH) were examined with thorax CT following their diagnostic or follow-up right-sided heart catheterisation (RHC). Images of the whole thorax were acquired with a 128-slice dual-energy CT scanner. After lung identification, a vessel enhancement filter was used to estimate the lung vessel centerlines. From these, the vascular trees were generated. For each vessel segment the tortuosity was calculated using distance metric. Fractal dimension was computed using 3D box counting. Hemodynamic data from RHC was used for correlation analysis.

Distance metric, the readout of vessel tortuosity, correlated with mean pulmonary arterial pressure (Spearman correlation coefficient: ρ = 0.60) and other relevant parameters, like pulmonary vascular resistance (ρ = 0.59), arterio-venous difference in oxygen (ρ = 0.54), arterial (ρ = −0.54) and venous oxygen saturation (ρ = −0.68). Moreover, distance metric increased with increase of WHO functional class. In contrast, 3D fractal dimension was only significantly correlated with arterial oxygen saturation (ρ = 0.47).

Automatic detection of the lung vascular tree can provide clinically relevant measures of blood vessel morphology. Non-invasive quantification of pulmonary vessel tortuosity may provide a tool to evaluate the severity of pulmonary hypertension.

Trial Registration

ClinicalTrials.gov NCT01607489