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Fundus Photography Analysis Example

This example demonstrates Apolo's dual-level explainable approach to analyzing a fundus photograph with features suggestive of glaucoma. Follow the workflow from image input to description generation (Stage 1) to diagnostic reasoning (Stage 2).

Fundus Photography Example

Sample fundus photograph used for analysis

Stage 1: Apolo-Vision (Description Generation)

The Apolo-Vision module (based on Llava-v1.6 with Llama-3 8B) analyzes the image and generates a detailed, objective description of all visible features, without making diagnostic claims.

Description Output
Prompt Used

Ophthalmology Image Descriptive Report

Examination: Color Fundus Photography, Posterior Pole View.
Eye: Unspecified (Orientation suggests Right Eye, but cannot be confirmed without metadata).
Clinical Indication: Not Provided.

Technique/Image Quality: Illumination appears somewhat globally reduced but is adequate for visualization of major posterior pole structures. Focus is reasonable across the central field. Good centration capturing the optic disc and macula. No significant artifacts obscure central details. Media appear clear.

Findings:

  • Optic Disc:
    • Location: Positioned nasally within the image field.
    • Size/Shape: Appears generally round, estimated vertical diameter appears within normal range relative to vessel caliber.
    • Margins: Margins appear distinct and well-defined circumferentially.
    • Neuroretinal Rim (NRR): The rim tissue exhibits noticeable pallor (paler than expected pink/orange hue). There is visible thinning of the NRR, most prominent in the inferior sector, followed by the temporal sector. The superior and nasal rim sectors appear relatively better preserved but may also exhibit mild pallor. The inferior rim appears significantly narrowed, approaching the disc margin.
    • Optic Cup: The central excavation (cup) appears significantly enlarged, particularly in the vertical dimension, giving it a vertically oval shape. The cup appears deep, with visible lamina cribrosa pores suggested at the base. The temporal aspect of the cup appears excavated towards the disc margin.
    • Cup-to-Disc Ratio (Visual Estimate): Vertical C/D ratio is visually estimated at 0.8. Horizontal C/D ratio is estimated at 0.7.
    • Vessels: Central retinal vessels emerge from the central/nasal aspect of the cup. The pattern shows a degree of nasalization (vessels shifted nasally). Bayoneting sign (sharp angulation of vessels at the cup margin) is subtly suggested inferiorly.
    • Peripapillary Area: A zone of peripapillary atrophy (beta-zone like appearance with visible sclera and larger choroidal vessels) is noted temporally. No definite disc hemorrhages (e.g., Drance hemorrhage) are identified.
  • Retinal Vasculature:
    • A/V Ratio: Retinal arteries appear generally attenuated (narrowed) compared to the caliber of corresponding veins. The estimated Artery-to-Vein ratio is reduced, approximately 1:3.
    • Caliber/Tortuosity: Vessels follow a relatively straight course without significant tortuosity. No focal areas of vascular sheathing or occlusion are apparent.
    • AV Crossings: Arteriovenous crossings appear unremarkable in the visualized field; no definite signs of nicking, banking, or Gunn's sign are clearly discernible at this resolution.
    • Other Lesions: No definite hemorrhages (dot, blot, flame), microaneurysms, hard exudates, cotton wool spots, or signs of neovascularization (NVD, NVE) are identified along the major vascular arcades or elsewhere in the posterior pole.
  • Macula:
    • Location: Located temporal to the optic disc.
    • Foveal Reflex: The normal pinpoint foveal light reflex appears absent or markedly blunted.
    • RPE/Texture: The macular region displays a subtle granular or finely mottled appearance of the retinal pigment epithelium (RPE). No pigment clumping or areas of geographic atrophy are clearly visible.
    • Lesions: No definite drusen (hard or soft), macular edema (indicated by retinal thickening or cysts), subretinal fluid, pigment epithelial detachments, or choroidal neovascular membranes are clearly visible within the macula.
  • Background Retina/Periphery:
    • Color/Texture: The visible background retina has a generally uniform orange-red appearance, consistent with fundus background coloration, possibly slightly pale overall. The choroidal pattern is partially visible through the RPE.
    • Lesions: No definite peripheral hemorrhages, exudates, tears, detachments, or suspicious pigmented lesions are noted within the visualized field. A small, indistinct darker spot noted superiorly near the edge is likely an artifact or out-of-focus structure.

Descriptive Summary (Non-Diagnostic):
Key visual findings include a significantly enlarged vertical cup-to-disc ratio (estimated 0.8) with associated pallor and marked thinning of the inferior and temporal neuroretinal rim, and vessel nasalization. Retinal arterioles appear attenuated (A/V ratio est. 1:3). Macular findings include an absent/blunted foveal reflex and subtle RPE granularity. No definite signs of diabetic retinopathy, hypertensive retinopathy, or exudative macular degeneration are visualized. The peripapillary area shows temporal atrophy.

Prompt Used for Stage 1

Generate a highly detailed, objective, non-diagnostic description of the following medical image:

Image Type: Color Fundus Photography
View: Posterior Pole
Key Structures to Describe: Optic Disc, Macula, Retinal Vessels, Background Retina

Instructions:
1. Analyze systematically by anatomical region, providing comprehensive detail about visible features
2. Include precise observations about each key structure, including measurements where possible
3. Do NOT include any diagnostic conclusions, differential diagnoses, or management recommendations
4. Structure in a standard clinical format with appropriate sections and subsections
5. Include a descriptive summary at the end that remains purely objective

Format your response as a markdown report with appropriate headings and bullet points.

Stage 2: Apolo-Dx (Diagnostic Reasoning)

The Apolo-Dx module (based on Mistral-Nemo-Instruct-2407 12B, quantized) receives only the textual description from Stage 1. It performs diagnostic classification and provides explicit reasoning steps.

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Objective: Assess the likelihood of ophthalmic conditions based on the provided descriptive report.

Input Analysis (Key Findings from Description):

  1. Optic Disc: High C/D ratio (V:0.8, H:0.7), NRR pallor & thinning (esp. inferior, temporal), deep cup, vessel nasalization, subtle bayoneting, temporal PPA. No disc hemorrhage.
  2. Vasculature: Arteriolar attenuation (A/V ~1:3). No hemorrhages, MAs, exudates, CWS, NV.
  3. Macula: Absent/blunted foveal reflex, subtle RPE granularity. No drusen, edema, SRF.
  4. Background: Unremarkable.

Reasoning Process:

  • The constellation of optic disc findings (large C/D ratio >0.7, NRR thinning conforming to common patterns like ISNT rule violation [implicitly, by severe inferior/temporal thinning], pallor suggesting nerve fiber loss, vessel nasalization, possible bayoneting) is the most prominent feature set. These are classic, strong indicators of glaucomatous optic neuropathy. The depth of the cup and potential lamina cribrosa visibility further support significant structural change. Temporal PPA is often associated with glaucoma.
  • The absence of disc hemorrhage doesn't rule out glaucoma, as these are often transient.
  • The vascular attenuation is noted but less specific. It could indicate co-existing systemic vascular disease (e.g., hypertension) but doesn't point strongly to primary hypertensive retinopathy given the lack of other signs.
  • Macular findings (blunted reflex, RPE granularity) are non-specific for glaucoma but indicate some abnormality. They don't strongly suggest primary macular diseases like advanced AMD or diabetic macular edema based on the exclusions in the description.
  • The absence of diabetic/hypertensive retinopathy signs makes these less likely as the *primary* pathology explaining the optic nerve changes.

Synthesis: The overwhelming evidence from the description points towards structural damage characteristic of glaucoma. Other findings are either non-specific or secondary.

Conclusion Formulation: State the primary suspected condition based on the dominant findings.

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Prediction: High Probability of Glaucomatous Optic Neuropathy (Probability: 0.96)