Imaging Techniques in Ophthalmology PDF

IMAGING TECHNIQUES IN OPHTHALMOLOGY Dr. Fatima Walid Al-Rawi, M.B., Ch. B. , C.A.B.M.S.O.,F.R.C.S. (G),M.R.C.S.I.,I.C.O. Duhok College of Medicine, Duhok University. Specialist Ophthalmologist at Duhok Eye Hospital.  OBJECTIVES A. ANTERIOR AND POSTERIOR SEGMENT IMAGING SY...

IMAGING TECHNIQUES IN OPHTHALMOLOGY Dr. Fatima Walid Al-Rawi, M.B., Ch. B. , C.A.B.M.S.O.,F.R.C.S. (G),M.R.C.S.I.,I.C.O. Duhok College of Medicine, Duhok University. Specialist Ophthalmologist at Duhok Eye Hospital.  OBJECTIVES A. ANTERIOR AND POSTERIOR SEGMENT IMAGING SYSTEM SLIT-LAMP BIOMICROSCOPY B. ANTERIOR SEGMENT IMAGING SYSTEM CONFOCAL MICROSCOPY SPECULAR MICROSCOPY KERATOMETRY SCHEIMPFLUG IMAGING TECHNIQUE ---CORNEAL TOPOGRAPHY ANTERIOR SEGMENT OPTIC COHERENCE TOMOGRAPHY ULTRASOUND BIOMICROSCOPY (UBM) C. POSTERIOR SEGMENT IMAGING SYSTEM FUNDUS CAMERA FUNDUS FLUORESCEIN ANGIOGRAPHY (FFA) INDOCYANINE GREEN ANGIOGRAPHY SCANNING LASER OPHTHALMOSCOPE (SLO) SCANNING LASER POLARIMETRY OPTICAL COHERENCE TOPOGRAPHY OCULAR ULTRASONOGRAPHY D. ORBIT IMAGING SYSTEM COMPUTERIZED TOMOGRAPHY (CT) MAGNETIC RESONANCE IMAGING (MRI) ANGIOGRAPHY-CTSC AND MRA E. OPTIC NERVE AND RETINAE FUNCTION IMAGING SYSTEM PERIMETERY ELECTROPHYSIOLOGICAL TESTS F. LACRIMAL IMAGING SYSTEM CONTRAST DACRYOCYSTOGRAPHY NUCLEAR LACRIMAL SCINTIGRAPHY Anterior and Posterior Segment Imaging System  Slit-lamp Biomicroscopy The slit lamp biomicroscopy is an important tool in ophthalmic practice. It is basically designed for examination of anterior segment but with the appropriate attachments, all ocular structures can be viewed. Advantage ---------stereopsis, in other words ophthalmologist can examine eye structures in three dimensions. Two major parts 1. The illumination System :: projects bright slit light onto the focus plane------delivers very sharp, thin and undistorted slit light in order to view true representation of the ocular structures. Blue and green filters ---visualize fluorescein stain, micro-aneurysms and nerve fiber layer. 2. Observation part comprises many optical lenses in order to deliver magnified view of ocular structures. Its magnification range differs between 5x to 40x.It can enable magnification by flip-type, Galilean rotating barrel and continuous zoom methods. Anterior Segment Imaging System  Confocal Microscopy A non-invasive histological imaging technique. It uses reflected light from the living tissue. Therefore, it is an in vivo imaging method of the living cornea. Clinical applications : 1. Qualitative properties of cornea can be documented such as corneal thickness measurement, depth of surgical interfaces, densities of stromal and endothelial cells, density or nerves. 2. Inherited corneal diseases. -----screening of unaffected family members 3. Acanthamoeba keratitis, fungal keratitis, bacterial and viral keratitis 4. Wound healing response can be analyzed after refractive surgery. Acanthamoeba Keratitis Inflammatory Cells  SPECULAR MICROSCOPY A noninvasive diagnostic tool that allows for in vivo 1. Evaluation of corneal endothelium in health and various diseased states(FED, Contact lens-induced hypoxia) 2. Evaluation of donor corneas and assessing the suitability for various types of keratoplasty. A slit of light is focused on the corneal endothelial surface and specularly (mirror-like) reflected light rays are focused onto film plane for viewing on a real-time monitor. Human corneal endothelium does not regenerate. Any focal endothelial injury/loss of endothelial cell is repaired by maintaining its continuity by migration and expansion of surviving cells. Parameters -------1. Percentage of hexagonal endothelial cells(Deviation from hexagonality Pleomorphism)--- good index of progress of endothelial wound healing. 2. Coefficient of variation of cell area ( in the variability of cell area Polymegathism)--- corneal endothelial dysfunction corneal endothelial dysfunction 3. Endothelial cell density. Healthy cornea 60% of the hexagonal endothelial cells. 5000-6000 cells/mm2 At birth 3500 cells/mm2 Age 5 years 3000 cells/mm2 Age 14-20 years 2500 cells/mm2 in late adulthood (a) The normal, hexagonal mosaic. (b) Endothelial failure.(Fuchs endothelial corneal Dystrophy (FECD)) The normal mosaic is no longer visible and the endothelium is studded with drop-like excrescences (guttae) located in Descemet’s layer. FUCHS ENDOTHELIAL DYSTROPHY BULLOUS KERATOPATHY CORNEAL TRANSPLANT  KERATOMETRY The shape of the cornea (the radius of curvature) can be measured from the image of a target reflected from its surface. K-READINGS (K1 AND K2 ) 1. Contact lens assessment 2. Refractive Surgery 3. Calculating the power of an artificial lens implant in cataract surgery. 4. Detect aberrations of shape such as a conical cornea (keratoconus). Photo-keratometry ((very accurate contour map of the cornea)).  Scheimpflug Imaging Technique Corneal Topography Provides high resolution and wide depth-of-focused sharp images from anterior corneal surface to the posterior crystalline lens capsule. System One ::::: Scanning Camera with a monochromatic slit light source rotates from zero to 180° ----slit images --- each one of the photographs belongs to the specific angle of corneal section.Static camera detects pupil contours and controls fixation. System Two:::: Galilei dual Scheimpflug analyzer which integrates a placido disc with a dual rotating Scheimpflug system. Both systems acquire images simultaneously to obtain information on the curvature and elevation of the cornea. After scanning the anterior chamber, Scheimpflug images ------------------------- transferred to PC to get analyzed and used to construct 3-D model of the anterior segment of the eye. Calculates the real relationship of the posterior corneal surface to the anterior corneal surface. Examples Pentacam and Orbiscan.  Topography Maps ( with Pachymetry) : A. Refractive power for patients :::::::: For planning pre-surgical (REFRACTIVE SURGERY) or have undergone refractive corneal surgeries. B. Keratoconus screening tool and early detection. C. Contact Lens Fitting module -------measurement data for fitting contact lenses. Pachymetry Maps : A. For pre-surgical planning of implantation of phakic IOLs, pre-post operative comparison of changes in anterior chamber. Assessment of anterior chamber volume, angle B. Glaucoma screening, pachymetry-based IOP correction (CENTRAL CORNEL THICKNESS) NORMAL CORNEA KERATOCONUS (ABNORMAL CORNEA)  Anterior Segment Optic Coherence Tomography (AS-OCT) A non-contact imaging method which provides detailed cross-sectional images of biological tissues. OPTIC Cu It works with similar principle with ultrasound imaging. Delay time of reflected light is measured and used to visualize the target tissue in depth. A beam of infrared light is used instead of sound wave. Resolution of OCT depends on the coherence length of the light and ranges from 2 µm to 20µm.  CORNEA ::: 1. Pachymetry map helps preoperative prediction of keratoconus and postoperative evaluation of ectasia and corneal thinning. 2. Placement of intracorneal ring segments ( avoid depth related complications) 3. Pre-operative evaluation of keratorefractive surgery. 4. It is also useful in analysis of corneal wound structure after refractive surgery, depth of injury due to a foreign body, laceration or ocular burn 5. Before corneal transplants. graft donor tissue thickness and structural preservation 6. After corneal transplants ,for example ,descement stripping endothelial keratoplasty(DSEK)----detects posterior lamellar dislocation, primary graft failure , Detect descement membrane detachment ((corneal ))) after corneal transplant or cataract extraction. 7. A valuable tool in determining the hereditary or infective corneal pathologies (corneal infiltrates as hyperreflective areas). ANTERIOR CHAMBER ::: Measurement of chamber depth is useful in sizing and predicting the postoperative position of phakic intraocular lenses to the corneal endothelium. GLAUCOMA 1. Specific dimensions of the iris and chamber angle(depth) provided by AS-OCT can be used in predicting the development of angle-closure glaucoma 2. Evaluating anterior chamber anatomy and positioning filtering devices after glaucoma surgery   Ultrasound Biomicroscopy (UBM) Allows in vivo detailed assessment of anterior segment structures even if an optical opacity is presented. Based on 50-100 MHz transducers which are incorporated into a B mode clinical scanner. Penetration decreases but, resolution increases with the increasing frequency. It requires supine positioning of the patient and ocular contact with a coupling gel or fluid bath. During the examination, transducer moves continuously. Provide 25µm axial resolution and 50µm lateral resolution. Tissue penetrations of these devices are approximately 4-5 mm  GLAUCOMA 1. Classification of angle closure glaucoma (anatomic differences) 2. Pigmentary glaucoma, malignant glaucoma and other glaucoma types. 3. Defining the mechanisms and results of various types of glaucoma surgery. CORNEA 1. Visualize patients with opaque corneas before making decision for corneal transplantation 2. Depth of anterior chamber, state of the angle, presence of synechiae and position of intraocular lens (IOL) can be determined before surgery. SCLERA It can differentiate extra-scleral and intra-scleral diseases and degree of scleral thinning. TRAUMA 1. Traumatic hypotony--------detect cyclodialysis cleft even in the presence of anterior chamber swallowing 2. Occult wound leakage, ciliary body membranes. 3. Anterior chamber traumatic opacities and can detect small foreign bodies TUMOURS Management of anterior segment tumors With Intracamellar Lens Posterior Segment Imaging System  Fundus Camera A specially designed low power microscope. Takes photo (((posterior pole of the eye with an attached camera))). It is used for 1. imaging the eye, 2. monitoring progression of a disease and 3. screening purposes. 4. Diagnostic purposes (retinal angiograph and autofluorescence , Red Free attachment) WIDE FIELD and Stereo Fundus camera color fundus photography. Mostly used for follow-up of glaucoma and diabetic retinopathy ((share with patient’s condition or colleagues)). Document macular edema, newly occurred micro aneurysms and neovascularisation clearly or pigmented choroidal lesions (Naevus or Melanoma). NORMAL DIABETIC RETINOPATHY BRANCH RETINAL ARTERY OCCLUSION  Fundus Fluorescein Angiography (FFA) Ideal for visualizing retinal vessels. Fluorescein molecular weight 376.67 daltons and it is highly water soluble. Excitation wavelength is 465 to 490 nm ((exposed to a specific wavelength light)) Fluorescence wavelength is 520-530 nm ((give off longer wavelength light ))) Molecular weight is too large to pass through the RPE cells (Outer blood-retina barrier) and large choroidal vessels. Small enough to diffuse easily through the capillaries except central nervous system and retina (inner blood retina barrier). Able to leak from disrupted blood-retina barrier areas. 80-85% of fluorescein binds to plasma proteins especially albumin (((free fluorescein)) is able to absorb and emit light. Mild reactions :::::: nausea, emesis, pruritus and vasovagal symptoms. Severe reactions :::: laryngeal edema, broncho spasm, anaphylaxis, shock, myocardial infarction, cardiac arrest and convulsion. Contraindications Pregnancy, congestive cardiac, renal and hepatic failures. After administration of fluorescein several phases can be seen in retinal circulation. The choroid-----Arterial filling ---- Laminar filling----Venous filling phase ------ Recirculation phase  NORMAL FFA a) A branch retinal vein occlusion. (b) New vessels leak on the fluorescein angiogram (arrowed). The retina peripheral to the leakage is dark due to the reduced capillary circulation in this area. The new vessels have also bled, creating a pool of blood with a horizontal level, lying between the retina and the posterior vitreous face (small arrows).  Indocyanine Green Angiography Investigations for visualizing the choroidal vasculature. Indocyanine green is a water soluble dye and molecular weight is 775 daltons. It absorbs near-infrared light the range of 790-805 nm. Emission spectrum is in the range of 770-880 nm, peak at 835 nm. Indocyanine green bounds to plasma proteins with 98 Indocyanine dye cannot escape from choroidal vasculature and allows visualizing of the choroidal vasculature. ICG diffuses through the choroidal stroma slowly. Image acquisition from ICG done by the near infrared laser or light through the excitation filter.  Clinical Consideration : 1. Detection and follow-up of AMD related lesions.(( Serous pigment epithelial detachment PED)) ((Choroidal neovascularization (CNV)))) 2. Polypoidal choroidal vasculopathy (PCV) is an abnormality of the choroidal circulation. 3. Intraretinal neovascularization, hemorrhages and exudates. In ICG. 4. Central serous chorioretinopathy ((collection of fluid under the retina)) 5. Valuable diagnostic tool in the evaluation of intraocular tumors ((( e.g Pigmented choroidal melanomas)) 6. Intraocular inflammatory conditions. NORMAL ICG  HAEMORRHAGE ICG WITH FFA CHOROIDAL MELANOMA CHOROIDAL NEOVASCULARIZATION with HAEMORRHAGE AND POST TREATMENT WITH ANTI VEGF  Scanning Laser Ophthalmoscope (SLO) Used for FFA, ICG angiography, autoflourescence detection and acquiring OCT images with modification. Combination of low powered laser illumination and confocal imaging technique provides high contrast and detailed images. Heidelberg Retinal Tomography (HRT) and Heidelberg Retinal Angiography (HRA). HRT is designed to acquire images from especially optic nerve and macula. It provides quantitative three dimensional imaging of the posterior segment. Analysis of retinal thickness and optic nerve topography (((GLAUCOMA))). HRA is a confocal SLO designed for simultaneous FA, ICG angiography and autoflourescence imaging.  Scanning Laser Polarimetry Use of polarised light to measure the thickness of the retinal nerve fiber layer as part of a glaucoma workup. Based on the birefringent properties of the RNFL.  OPTICAL COHERENCE TOPOGRAGHY Digital imaging and laser scanning techniques Quantitative assessment (noninvasive) of features such as the area of the optic disc and optic disc cup and the size of retinal lesions. These will help in the assessment of patients with chronic diseases such as glaucoma, diabetes and macular degeneration, where the management requires an accurate assessment of any change over time. OCT uses super luminescent diode to obtain a coherent laser beam for imaging the retina. interferometry --------in vivo cross- sectional map of the retina at a resolution f 10–15 μm. Sufficient media clarity is needed to obtain OCT scans. OCT TYPES ----DOPPLER----ANGIOGRAPHY OCT scan of the macular region of retina. The scan represents the retina underneath the green line on the fundus picture. Note the depression at the fovea. The scan allows the layers of the retina to be seen.  MACULA 1. Monitoring disease progression and response to therapies such as AMD, diabetic macular edema and vein occlusions. 2. Accurate measurement of the retinal thickness ( clinical decision ------ treatment )))) 3.Diagnosing and classification of the macular holes ((((Predicting the surgery outcomes)) RETINA 1. It allows evaluation of the vitreoretinal interface in epiretinal membrane and vitreoretinal traction 2. Monitoring retinopathy toxicity of some therapies like with chloroquinolone. OPTIC NERVE 3. Determining the retinal nerve fiber layer profile with OCT provides valuable information in detecting and management of glaucoma patients. An OCT scan showing diabetic macular oedema. Note the cystic spaces in the retina demonstrating the accumulation of fluid on the greyscale picture on the right. The coloured circle represents the thickness of the macula as a contour map. Note the significant thickening in the central foveal region shown as white. CSR-Subretinal Fluid MACULAR HOLE  Ocular Ultrasonography Ultrasound is a safe, non-invasive, widely used diagnostic tool in medical imaging. Two-dimensional cross-sectional views of the eye and orbit. Imaging intraocular lesions in the presence of anterior segment opacities (cataract) or vitreous haemorrhage. Ultrasound devices produce acoustic sound waves above the audible range of 20KHz to visualize ocular and orbital tissues. Transducer ---- converting electric energy into the ultrasound-----returned echoes-----electrical signal and image of the tissue is created Ophthalmic ultrasound devices use 8-100 MHz frequency echoes.  A. A-scan imaging is a one dimensional display of echo strength over time. Vertical height corresponds to echo intensity. 1. (BIOMETRICAL )Biometry : Axial Length measurement+++ Corneal Pachymetry (((ocular hypertension )) and calculation of intraocular lens power (((IOL))) 2. (STANDARIZED) Determine and differentiate abnormal intraocular tissues. PROBE ORBITAL FAT  B. B-scan is the two dimensional view of the combined multiple A-scan echoes. Every spike is encoded as a bright dot and every dot brightness changes with the strength of the echo. 1. Provide shape, location and extensive information of ocular lesions. 2. Evaluating intra ocular tissue integrity. 3. Searching and diagnosing intraocular foreign bodies, 4. Assessment of intraocular or peri-ocular lesions (Choroidal Masses ) determining intralesional characteristics+++ ecographic nature of a visible mass or foreign body. C. Color-doppler ultrasonography -------blood flow Valuable information about vasculature of orbital tumors, carotid disease, central retinal artery and vein occlusions and non-arteritic ischemic optic neuropathy. D. Ophthalmic 3D ultrasonography ----- three-dimensional blocks with the help of bundled software. Useful for calculating the volume of the intraocular lesions.  If Haemangioma appears highly Retinal reflective on A-Scan Detachment Collar Stud Sign Choroidal Melanoma RD in Diabetic Patient Attachment At Site Of Optic Nerve Orbital Imaging System  Computerized Tomography (CT) Uses X-rays but it emits a thin collimated fan shaped beam. The beam is attenuated as it passes through the tissues and detected by array of special detectors-------electrical signals from attenuated X-rays and then signals are converted to the images. A. Allows ------detect location, extent and configuration of the lesion. Orbit and Ocular(((Anatomical Detail ))) B. Provides tissue mass composition. C. Helps planning of an appropriate surgical approach to minimize morbidity. Spatial resolution of CT scan depends on slice thickness. Thinner slices have higher resolution. Optimal slice thickness for eye and orbit is 2 mm Requires less time and cheaper than magnetic resonance imaging (MRI). Tissue density is represented by a grey scale, white being maximum density (e.g. bone) and black being minimum density (e.g. air). Exposes the patient to ionizing radiation INDICATIONS 1. Orbital trauma, for the detection of bony lesions such as fractures (Fig. 19.1A), blood, herniation of extraocular muscles into the maxillary sinus and surgical emphysema. 2. When MR is contraindicated (e.g. patients with ferrous foreign bodies). 3. Evaluation of the extraocular muscles in thyroid eye disease. 4. Orbital cellulitis for assessment of intraorbital extension and subperiosteal abscess formation 5. Bony involvement of orbital tumours. Iodinated contrast agents are used for enhancement to detect intracranial extension 6. Detection of intraorbital calcification as in meningioma and retinoblastoma 7. Detection of acute cerebral or subarachnoid haemorrhage. 8. Unexplained proptosis, ophthalmoplegia, ptosis, palpable orbital mass and orbital signs of paranasal sinus diseases. The CT appearance of a pituitary tumour (arrow). (b) The bitemporal visual field loss produced. A CT scan showing a left cortical infarct. (b) The complete congruous right homonymous hemianopia produced by the infarct A CT scan showing a left-sided orbital metastasis. Blowout Fracture  Retrobulbar Haemorrhage  Intraocular Foreign Body BRIGHT Rupture Globe  Magnetic Resonance Imaging (MRI) Uses non-ionizing radiation. It is based on the ability of a small number of protons within the body to absorb and emit radio wave energy when the body or tissue is exposed to strong magnetic field. Different tissues (Differences in the density of protons) absorb and release radio wave energy at different characteristic rates. Contrast materials enhance recognition of primary pathology by demonstrating areas of breakdown of the blood- brain barrier. Visualize the tissue in SAGITTAL , CORONAL and AXIAL planes. Visualize vascular tissues with or without contrast material Relatively expensive. Does not image bone. Does not detect recent haemorrhage Claustrophobia (((a problem))). Cardiac pacemakers or implanted ferromagnetic foreign bodies are contraindications for MRI. Requires the patient to cooperate and remain motionless.  1. T1 images measures ability of protons in a tissue to exchange energy with the surrounding environment (( how fast the tissue is magnetized))). A. Viewing anatomy. B. Hypointense (dark) structures include CSF and vitreous. C. Hyperintense (bright) structures include fat, blood, contrast agents and melanin 2. T2 images measures how quickly the tissue loses its magnetization. A. Valuable for detecting pathology B. Hypointense Fat and Blood vessels appear black on T2 imaging (((( unless occluded))) C. Hyperintense (water) oedematous tissue (e.g. inflammation) will be of brighter signal than normal surrounding tissue. D. CSF and vitreous are hyperintense as they have high water content.  Gadolinium Remains intravascular unless there is a breakdown of the blood– brain barrier. Enhancing lesions such as tumours and areas of inflammation will appear bright. Fat-suppression techniques are applied for imaging the orbit because the bright signal of orbital fat on conventional T1-weighted imaging frequently obscures other orbital contents. Fat-suppression eliminates this bright signal and better delineates normal structures (optic nerve and extraocular muscles) as well as tumours, inflammatory lesions and vascular malformations. T1 fat saturation ----abnormal enhancement (optic nerve sheath) to be visualized. STIR (Short T1 Inversion Recovery) intrinsic lesions of the intraorbital optic nerve (optic neuritis). FLAIR (fluid-attenuated inversion recovery) suppress the bright CSF on T2- weighted images ------------------ allow better visualization of adjacent pathological tissue such as periventricular plaques of demyelination((MULTIPLE SCLEROSIS)  DEMYELINATING PLAQUES PERIVENTRICULAR WHITE MATTER MULTIPLE SCLEROSIS  Choroidal Melanoma with Extraocular Extension INDICATIONS 1. Optic nerve coronal STIR images in conjunction with coronal and axial T1 fat saturation post-gadolinium images. Lesions of the intraorbital part of the optic nerve (e.g. neuritis, gliomas) 2. Intracranial extension of optic nerve tumours 3. Optic nerve sheath lesions (e.g. meningiomas) enhance avidly with gadolinium 4. Sellar masses (e.g. pituitary tumours) ----T1-weighted contrast-enhanced studies. Coronal and coronal images optimally demonstrate the contents of the sella turcica as well as the suprasellar and parasellar regions. 5. Cavernous sinus pathology. 6. Intracranial lesions of the visual pathways (e.g. inflammatory, demyelinating, neoplastic and vascular).  Angiography These are digital subtraction angiography, CT-angiography and MR-angiography. Digital subtraction angiography uses X-rays and iodine based intra-arterial contrast material. Imaging intra- and extra-cranial vasculature and in the diagnosis of cerebral aneurysms. CT-angiography.Intracranial aneurysms MR-angiography. Stenosis, dissection, occlusion, arteriovenous malformations and aneurysms Computed tomographic venography. Images are acquired in the venous phase of contrast enhancement. Conventional catheter angiography.Internal carotid and vertebral arteries in the neck under fluoroscopic guidance. Following contrast injection images are taken in rapid succession. Intracranial aneurysms Optic Nerve And Retinae Function Imaging System  Perimetery The Visual Field produces a hill of vision. Objects resolved in finest detail are at the peak of the hill (representing the fovea) Acuity falls towards the periphery. On the temporal side of the field is the blind spot, which corresponds to the position of the optic nerve head, where there are no photoreceptors. Machines permit more accurate plotting of the visual field. There are two types: Kinetic perimeters: For example, Goldmann perimeter. Static perimeters: These techniques are particularly useful in chronic ocular and neurological conditions, to monitor changes in the visual field (e.g. in glaucoma or compressive lesions of the visual pathway).  Electrophysiological Tests The electrical activity of the retina and visual cortex in response to specific visual stimuli, for example a flashing light, can be used to assess the functioning of Retina (electroretinogram or ERG) VEP RPE (electrooculogram) Visual Pathway (visually evoked response or potential). ERG EOG Lacrimal Imaging System  Contrast Dacryocystography Injection of radio-opaque contrast medium into the canaliculi followed by capture of magnified images. The test is usually performed on both sides simultaneously. It should also not be performed in a patient with acute dacryocystitis. 1. To confirm the site of lacrimal drainage obstruction, especially prior to surgery(DCR). 2. To diagnose diverticuli, fistulae and filling defects caused by stones or tumours  Nuclear Lacrimal Scintigraphy Assesses tear drainage under more physiological conditions than DCG. More sensitive in assessing incomplete blocks. Assessing physiological obstruction beyond the sac. Radionuclide technetium-99 is delivered by a micropipette to the lateral conjunctival sac --------gamma camera … THANK YOU FOR LISTENING AND ATTENDING