Can a prostate biopsy be safely deferred on PI-RADS 1,2 or 3 lesions seen on pre-biopsy mp-MRI?

Introduction: Multi-parametric magnetic resonance imaging (mp-MRI) is currently used to triage patients with suspected prostate cancer, before deciding on prostate biopsies. In our study, we evaluated normal and equivocal pre-biopsy mp-MRIs to see whether it is safe to avoid biopsy with such findings. Methods: A retrospective study was conducted at a district general hospital in the UK between August 2017 and July 2018. Patients with negative and equivocal prebiopsy mp-MRI with high clinical suspicion of cancer had proceeded to biopsy. MRI reports with prostate imaging reporting and data system (PI-RADS) scores 1, 2, 3 and normal MRI were evaluated against the transrectal ultrasound-guided prostate biopsy (TRUS-PB) outcomes to demonstrate benign pathology, clinically insignificant or clinically significant cancer (csCa). CsCa was defined as Gleason score (GS) ≥3 + 4. Results: Out of 265 mp-MRIs studied, five (1.9%) were PI-RADS 1, 109 (41.1%) and 84 (31.7%) were PI-RADS 2 and 3 lesions respectively; 67 (25.3%) were reported as normal. Seventy-five (27.3%) patients did not have biopsies following their MRI and 73.3% (51/75) of them had benign feeling prostate. Negative MRIs (PI-RADS 1, 2 and normal MRI) showed 8.8% and PI-RADS 3 lesions demonstrated 11.9% csCa. Negative predictive value for normal MRI was 91.2%. Mean PSA density (PSAD) among the benign, GS 3 + 3 and csCa was 0.14, 0.16 and 0.27 ng/ml/ml respectively and this was statistically significant (p < 0.001). The average percentage of cancer found in GS 3 + 3 and csCa was 3.2% and 20.1%, respectively. Conclusion: Avoiding TRUS-PB following normal or equivocal mp-MRI should carefully be decided as 18.5% of cancer was demonstrated in this group and 9.8% of those who were diagnosed with cancer were csCa. PSAD and DRE findings provide additional information to help with this decision.

A Lesson in Standardization - Subtle Aspects of the Processing of Samples Can Greatly Affect Dogs' Learning.

Training new medical odors presents challenges in procuring sufficient target samples, and suitably matched controls. Organizations are often forced to choose between using fewer samples and risking dogs learning individuals or using differently sourced samples. Even when aiming to standardize all aspects of collection, processing, storage and presentation, this risks there being subtle differences which dogs use to discriminate, leading to artificially high performance, not replicable when novel samples are presented. We describe lessons learnt during early training of dogs to detect prostate cancer from urine. Initially, six dogs were trained to discriminate between hospital-sourced target and externally-sourced controls believed to be processed and stored the same way. Dogs performed well: mean sensitivity 93.5% (92.2-94.5) and specificity 87.9% (78.2-91.9). When training progressed to include hospital-sourced controls, dogs greatly decreased in specificity 67.3% (43.2-83.3). Alerted to a potential issue, we carried out a methodical, investigation. We presented new strategically chosen samples to the dogs and conducted a logistic regression analysis to ascertain which factor most affected specificity. We discovered the two sets of samples varied in a critical aspect, hospital-processed samples were tested by dipping the urinalysis stick into the sample, whilst for externally sourced samples a small amount of urine was poured onto the stick. Dogs had learnt to distinguish target aided by the odor of this stick. This highlights the importance of considering every aspect of sample processing even when using urine, often believed to be less susceptible to contamination than media like breath.

Reliability and reproducibility of assessment of corneal epithelial thickness by fourier domain optical coherence tomography.

PURPOSE: To analyze the intra-user reliability and inter-user reproducibility of assessment of corneal epithelial thickness by Fourier domain optical coherence tomography. METHODS: In this consecutive cross-sectional case series performed at a tertiary ocular care institution, 210 eyes of 210 subjects underwent anterior segment Fourier domain optical coherence tomography (FDOCT). A caliper tool software was used to measure the corneal thickness. For the reproducibility measures, the examination was done by 2 examiners (user 1, user 2) within 30 minutes of each other. For the reliability measure, the retest was done by user 1 on the next day, within 30 minutes of the previous test's time. The total corneal thickness, epithelial thickness, and corneal thickness excluding the epithelium were measured. RESULTS: The mean corneal thickness of the population measured by user 1 was 519.5 ± 31.1 µm, 58.6 ± 4.2 µm, and 460.95 ± 31.4 µm for total cornea, epithelium, and non-epithelial cornea, respectively. The difference in results between user 2 and user 1 was 0.8 ± 7.2 µm, 0.23 ± 3.3 µm, and 0.7 ± 8.2 µm for total, epithelium, and non-epithelial cornea, respectively, and the difference in results between the repeated series by user 1 was 0.49 ± 5.7 µm, -0.13 ± 2.7 µm, 0.61 ± 5.4 µm total, epithelium, and non-epithelial cornea, respectively (paired t-test, P > 0.05). Intraclass correlations ranged from 0.87 to 0.99, coefficients of repeatability from 4.5 to 14.11, and coefficient of variation from 2.3% to 11.1%. CONCLUSIONS: Fourier domain anterior segment optical coherence tomography is reproducible and reliable for the measurement of epithelial thickness at vertex.

Endothelial cell loss associated with diffuse lamellar keratitis because of laser-assisted in situ keratomileusis.

PURPOSE: To report a case of severe interface inflammation, flap edema, and endothelial cell loss after laser-assisted in situ keratomileusis (LASIK). METHODS: A 22-year-old woman with no previous ocular abnormality underwent LASIK for myopia. The surgery was uneventful. Her preoperative endothelial count was 3,066 and 2,898 cells per square millimeter OD and OS, respectively. RESULTS: On the first postoperative day, the right eye had interface infiltrates, flap edema, and radiating Descemet's folds and the left eye had flap edema with interface infiltrates. Bilateral flap relifts and thorough irrigation were performed on the second day, followed by amputation of the nonviable flap in the right eye on the third day. On medical management, the corneal edema resolved for more than 1 month. At 6 months, the best-corrected vision was 20/32 OD and 20/25 OS, with endothelial cell count of 1,763 and 2,055 cells per square millimeter OD and OS, respectively. CONCLUSIONS: Endothelial status should be monitored in patients with a severe interface reaction or severe diffuse lamellar keratitis after LASIK.