Imaging

Details

Title

Imaging

Type

Stage Two

Module code

HPS260

Requirement

Compulsory

Module objective

By the end of this module the Clinical Scientist in HSST OVS will be able to apply their expert knowledge of the principles, instrumentation, methodology, clinical application and risks of imaging ocular structures, and analyse and integrate the results of both static and dynamic 2-D and 3-D images, including colour (RGB) fundus photography, fundus and anterior segment fluorescein angiography (FFA), indocyanine green angiography (ICG), fundus autofluorescence (FAF), optical coherence tomography (OCT), retinal nerve fibre layer (RNFL) analysis and ocular ultrasound. They will have an in-depth understanding of the clinical indications for each specific imaging modality and how best to acquire high-quality images, process and interpret them, and combine the information gained from different imaging modalities to inform and advise patient management as part of a multidisciplinary team. They will have an understanding of management systems for the integration, dispersal, storage and access of images. They will be aware of developments in technology that may be translated to and enhance ocular imaging. The Clinical Scientist in HSST will also be able to formulate an appropriate plan for investigation and management, in conjunction with medical colleagues, being aware of the need to expedite investigation in suspected serious disease, and they will consistently demonstrate the attitudes and behaviours necessary for the role of a Consultant Clinical Scientist.

Knowledge and understanding

By the end of this module the Clinical Scientist in HSST will be able to analyse, integrate, critically evaluate, apply their expert knowledge and summarise the findings with respect to:

• analysis and optimisation of high-magnification images of transparent structures, e.g. corneal endothelium and photoreceptors;
• development and application of novel imaging modalities, e.g. adaptive optics or wide field techniques to transparent structures.

Colour fundus photography:

• acquisition and montage of high-quality colour fundal images, including stereophotography, identifying landmarks and applying algorithms for the automatic detection of signs of diabetic retinopathy.age-related macular diseases for recognition of choroidal neovascularisation, pigment epithelial detachment and geographic atrophy;

Fluorescein angiography and ICG:

• principles of fluorescein angiography of anterior and posterior pole (FFA);
• principles of ICG;
• instrumentation used to perform FFA and ICG;
• methodology, equipment and clinical indications of simultaneous versus sequential FFA and ICG imaging with static or video imaging;
• staff requirements for performing FFA and ICG;
• Potential risks associated with intravenous/oral use of:
  • fluorescein sodium dye;
  • indocyanine green dye;
• systemic effects and potential side effects of fluorescein sodium dye and precautions to be taken following FFA imaging;
• staff requirements to deal with adverse reactions to fluorescein and indocyanine green;
• optimisation of image quality, including identification of artefacts and knowledge of how to avoid these where possible.

Phases of FFA and ICG imaging:

• interpretation of FFA and ICG images, and the causes of hyperfluorescence and hypofluorescence and of the patterns of fluorescence observed in various pathologies.

Clinical applications of FFA, including:

• retinal vascular diseases: to identify reduced circulation or vascular abnormalities, leakage (oedema versus new blood vessels), modified circulatory times. Used mainly in diabetes and venous obstruction;
• age-related macular diseases for recognition of choroidal neovascularisation, pigment epithelial detachment and geographic atrophy;
• macular dystrophies to identify pigmentary changes in the RPE;
• inflammatory diseases in immunocompromised and immunocompetent patients for identification of retinal vascular leakage or choroidal vascular changes;
• ocular tumours: to identify the presence or absence of intrinsic circulation;
• pharmacologic retinal toxicity to identify pigmentary changes in the RPE;
• optic nerve disease to verify optic nerve head swelling (leakage of dye).
• new advances in angiography, including digital subtraction, wide-field angiography, high-speed imaging and 3-D confocal angiography.

Clinical applications of ICG imaging, including:

• age-related macular degeneration (AMD);
• polypoidal choroidal vasculopathy;
• ICG-guided laser treatment of choroidal neovascular membranes in AMD;
• retinal angiomatous proliferation (RAP) lesions;
• central serous chorioretinopathy;
• chorioretinal inflammatory diseases;
• intraocular tumours.

FAF:

• principles of fundus autofluorescence imaging (FAF);
• lipofuscin properties, distribution and clinical relevance, including risk factors that may result in increased lipofuscin accumulation in the fundus;
• instrumentation and methodology used to perform FAF;
• factors affecting image quality;
• optimisation of image quality;
• interpretation of FAF images, and in particular recognition of the patterns of hypofluorescence and hyperfluorescence observed in various conditions;
• analysis of serial FAF images to track disease progression.

Clinical applications of FAF, including:

• AMD, including the different forms of AMD;
• inherited retinal disorders, e.g. cone-rod and rod-cone dystrophies; X-linked retinoschisis; ARB;
• inflammatory retinal disease;
• retinal vascular disease;
• other retinal disorders, e.g. paraneoplastic retinopathy, autoimmune retinopathy, AZOOR, etc.;
• macular dystrophies, e.g. Best disease, Stargardt fundus flavimaculatus;
• optic disc lesions;
• central serous chorioretinopathy;
• FAF phenotyping, particularly for AMD;
• prognostic value of FAF, including identification of predictive markers for assessing potential disease progression and monitoring progression of pathology.

OCT and retinal nerve fibre layer (RNFL) thickness:

• principles of optical coherence tomography (OCT), including the physics underpinning different types of OCT technology, e.g. time domain OCT, spectral or frequency domain OCT, swept source OCT, enhanced depth imaging (EDI);
• instrumentation used to perform OCT;
• methodology used to perform OCT, including selection of appropriate scanning protocols and settings, and patient fixation;
• relationship between OCT imaging and histology and with other retinal imaging techniques;
• factors affecting image quality;
• optimisation of image quality, including identification of artefacts and knowledge of how to avoid these where possible;
• interpretation of OCT images, including a sound understanding of the appearance of various abnormal features on OCT scans, the ability to differentiate between pathologies and artefact recognition;
• the importance of globe size, which affects the accuracy of measurements in view of the complexity of the mathematics involved in the calculation;
• comparison of serial OCT images.

Clinical applications of OCT, including:

• vitreo-macular interface disorders;
• AMD, including exudative and non-exudative AMD;
• inflammatory disease;
• diabetic retinopathy;
• other retinal vascular disease;
• inherited retinal disorders, e.g cone-rod and rod-cone dystrophies, X-linked retinoschisis, ARB;
• other retinal disorders, e.g. paraneoplastic retinopathy, autoimmune retinopathy, AZOOR, etc.;
• macular dystrophies, e.g. Best disease, Stargardt fundus flavimaculatus;
• other disturbances of macular function, e.g. macular oedema, central serous chorioretinopathy;
• retinal detachment;
• myopic degeneration;
• intraocular tumours;
• optic nerve/RNFL disease;
• glaucoma (use of anterior segment OCT and optic nerve head measurements for RNFL analysis);
• potential use of EDI in the assessment of the choroid and in the differentiation between benign and malignant choroidal lesions;
• anterior segment pathology;
• use of OCT in patient management, e.g. contribution of OCT measurements to macular hole prognosis, OCT-guided anti-VEGF re-treatment of AMD patients, new advances in OCT imaging including functional OCT (optophysiology), ultrawide field OCT and adaptive optics.

RNFL analysis, additional techniques:

• principles, physics and instrumentation used to image the RNFL, scanning laser polarimetry (SLP) and confocal scanning laser ophthalmoscopy (cSLO);
• methodology used to image the RNFL, including selection of appropriate scanning protocols and settings;
• factors affecting image quality for the different modalities used;
• optimisation of image quality;
• performing measurements on RNFL images, including the ability to recognise errors in automated measurements and to correct these errors.;
• interpretation of RNFL images, including identification of artefacts.

Clinical applications of RNFL imaging:

• glaucoma;
• optic neuritis;
• optic nerve disease;
• neurodegenerative disorders;
• pharmacological toxicity;
• comparison of serial RNFL images;
• correlation with functional measurements in particular visual fields, relating the ganglion cell distribution, visual field loss and peripapillary RNFL loss, understanding the role of RNFL analysis in patient management, e.g. glaucoma treatment.

Ultrasound

• principles and physics of ocular ultrasound;
• instrumentation used to perform ocular ultrasound;
• techniques used to perform ocular ultrasound examination;
• combination with blood flow measures and Doppler;
• factors affecting image quality;
• optimisation of image quality.

Clinical indications of ocular ultrasound, including:

• pathologies affecting the:
  • vitreous
  • retina
  • choroid
  • ciliary body
  • sclera
  • optic nerve
  • anterior segment
• interpretation of ocular ultrasound images, including understanding the echographic characteristics of various ocular pathologies;
• assessment of the typical features associated with the various ocular tumours, including differentiating between tumour types;
• optimisation of measurements, including axial length for optimal intra-ocular lens selection for cataract surgery or other refractive surgery;
• ultra high frequency ultrasound, ultrasound biomicroscopy, (UBM), ocular ultrasound and its clinical applications, in anterior segment imaging.

Technical and clinical skills

By the end of this module the Clinical Scientist undertaking HSST, with respect to Ophthalmic Imaging, will be able to demonstrate a critical understanding of current knowledge and research and its application to the performance and mastery of the following technical skills by:

• performing all modalities of ophthalmic imaging. They will apply their skills and advanced understanding of the factors affecting image quality and identify and avoid artefacts and optimise image quality;
• designing and developing new tests according to need and clinical condition;
• managing systems of image storage and integration.

For each procedure patient safety and comfort will be paramount.

While working within the scope of their practice, the Clinical Scientists in HSST will respond appropriately, calling on medical colleagues to safely address adverse reactions that may result from carrying out any of the above mentioned procedures.

By the end of this module the Clinical Scientist in HSST will be expected to critically reflect and apply in practice a range of clinical and communication skills to advise and communicate effectively with patients, relevant clinicians, patients and the public, and other healthcare professionals, and will:

• take a comprehensive history, understanding the nature of the visual complaint and select the imaging modality/s that will most appropriately investigate, diagnose, or monitor an individual patient and their clinical presentation according to signs, symptoms, medical and family history;
• work in partnership with the patient to optimise the imaging information by tailoring the imaging protocol appropriately, e.g. adjusting scan resolution;
• understand and advise on the contraindications and ensure risks are minimised;
• gain informed consent for the procedure;
• analyse all imaging data, identify artefacts, recognise and correct errors of automated software analysis;
• distinguish the imaging features of each technique in different healthy ocular tissues and in pathology, and interpret changes in serial images. They will acquire expert clinical skills for each technique to distinguish phenotypes, e.g. FAF phenotyping, identifying prognostic FAF markers;
• provide a clinical interpretation of the images, placing the results in the context of history and clinical examination;
• produce a clear and informative report with recommendations for further diagnostics and/or treatments;
• communicate, where appropriate, the implications of the findings to patients and families;
• reflect on the challenges of applying research to practice in relation to these areas of expertise, practice and suggest improvements, building on a critique of available evidence;
• take an integrative approach to diagnostic ophthalmic images that provide an accurate and comprehensive assessment of the patient’s clinical problem;
• strive to adapt current imaging modalities and develop novel investigations better to facilitate diagnosis and management;
• work in partnership with the patient to ensure the best quality images;
• reflect on the impact ophthalmic disorders have on everyday quality of life and on the family;
• use appropriate sensitivity dealing with patients and their families facing potentially poor visual or life prognosis.understand and advise on the contraindications and ensure risks are minimised;

Working within a multidisciplinary team they will advise future management as indicated and will refer appropriately to clinical colleagues in a timely manner.