Utility of a Low-Cost 3-D Printed Microscope for Evaluating Esophageal Biopsies

Abstract

In this manuscript we assessed the utility of a low-cost 3D printed microscope to evaluate esophageal biopsies. We conducted a comparative analysis between the traditional microscope and our 3-D printed microscope, utilizing a set of esophageal biopsy samples obtained from patients undergoing screening endoscopy. Two pathologists independently examined 30 esophageal biopsies by light microscopy and digital images obtained using a low-cost 3D printed microscope (Observer 1 and 2). The glass slide consensus diagnosis was compared to the findings of 2 additional pathologist who independently just reviewed the digital images (Observer 3 and 4). The intra-observer agreement was substantial to almost perfect for observer 1 (k:0.64) and 2 (k:0.84). All four observers had 100% sensitivity and negative predictive value, whereas specificity ranged from 59% to 100% and positive predictive value ranged from 21% to 100%. The PPV and specificity were lower for the two Observers (3 and 4) who just examined the digital images. Overall, our results suggest that telepathology may be used with high sensitivity and specificity, utilizing the pictures produced by our 3D-printed microscope.

Keywords: 3d-printer; low-cost; telepathology.

Figure 1.

Low-cost 3D printed microscope. A) front and B) back image of the low-cost 3D printed OpenFlexure microscope. C) electronic housing showing stepper motors (sm), motor drivers (dr), arduino board (ar), raspberry pi (rp), and condenser (co). D) Low-cost magnification objective using the raspberry pi camera and lens.

Figure 2.

Image comparison using low-cost 3D printed microscope and standard microscopy. A) reactive squamous mucosa light microscopy (40x), B) reactive squamous mucosa low-cost 3D printed microscope, C) squamous cell carcinoma using light microscope (40x) and D) squamous cell carcinoma using low-cost 3D printed microscope; E) reactive squamous mucosa light microscopy (200x), F) reactive squamous mucosa low-cost 3D printed microscope, G) squamous cell carcinoma using light microscope (200x) and H) squamous cell carcinoma using low-cost 3D printed microscope.

Figure 3.

Percent of tissue digitally scanned per sample

Figure 4.

Intra-observer agreement between the glass slide consensus and digital images for A) Observers 1, B) observer 2, C) Observer 3, and D) Observer 4. (NEG=Negative, LGD: Low grade dysplasia, MD: moderate dysplasia, HGD: High grade dysplasia, SCC: squamous cell carcinoma, RO LGD: cannot rule out low grade dysplasia, RO HGD: cannot rule out high grade dysplasia, RO INV: cannot rule out invasion.)