Impact of scan quality on AI assessment of hip dysplasia ultrasound

AIMS

Early diagnosis of developmental dysplasia of the hip (DDH) using ultrasound (US) is safe, effective and inexpensive, but requires high-quality scans. The effect of scan quality on diagnostic accuracy is not well understood, especially as artificial intelligence (AI) begins to automate such diagnosis. In this paper, we developed a 10-point scoring system for reporting DDH US scan quality, evaluated its inter-rater agreement and examined its effect on automated assessment by an AI system-MEDO-Hip.

METHODS

Scoring was based on iliac wing straightness and angulation; visibility of labrum, os ischium and femoral head; motion; and other artifacts. Four readers from novice to expert separately scored the quality of 107 scans with this 10-point scale and with holistic grading on a scale of 1-5. MEDO-Hip interpreted the same scans, providing a diagnostic category or identifying the scan as uninterpretable.

RESULTS

Inter-rater agreement for the 10-point scale was significantly higher than holistic scoring ICC 0.68 vs 0.93, p < 0.05. Inter-rater agreement on the categorisation of individual features, by Cohen's kappa, was highest for os ischium (0.67 ± 0.06), femoral head (0.65 ± 0.07) and iliac wing (0.49 ± 0.12) indices, and lower for the presence of labrum (0.21 ± 0.19). MEDO-Hip interpreted all images of a quality > 7 and flagged 13/107 as uninterpretable. These were low-quality images (3 ± 1.2 vs. 7 ± 1.8 in others, p < 0.05), with poor visualization of the os ischium and noticeable motion. AI accuracy in cases with quality scores <  = 7 was 57% vs. 89% on other cases, p < 0.01.

CONCLUSION

This study validates that our scoring system reliably characterises scan quality, and identifies cases likely to be misinterpreted by AI. This could lead to more accurate use of AI in DDH diagnosis by flagging low-quality scans likely to provide poor diagnosis up front.

Identification of novel antioxidative peptides derived from a thermolytic hydrolysate of ovotransferrin by LC-MS/MS

Ovotransferrin is a glycoprotein well-known for its iron-binding property. Ovotransferrin was reported to have antioxidative properties, but the presence of antioxidant peptides within the protein has not been reported. The purpose of the study was to characterize the antioxidant peptides within ovotransferrin. Ovotransferrin was sonicated and hydrolyzed by thermolysin, and peptides from the hydrolysate were fractionated by ion-exchange fast protein liquid chromatography and reversed-phase high-performance liquid chromatography. Fourteen peptides derived from ovotransferrin were characterized using LC-MS/MS, and their oxygen radical absorbance capacity (ORAC) values were determined using synthetic peptides. Two tetrapeptides (Trp-Asn-Ile-Pro and Gly-Trp-Asn-Ile) showed the highest antioxidant activity. Interestingly, the addition of amino acid residues to either the N or C terminus of the two peptides decreased the antioxidant activity, suggesting that the motif of Trp-Asn-Ile is responsible for the high antioxidant activity.

Genetic diversity of the Helicobacter pylori haemagglutinin/protease (hap) gene

Helicobacter pylori has been associated with the etiology of gastritis, gastric and duodenal ulcers and gastric cancer in man. In this study we confirm the presence of the haemagglutinin/protease (hap) gene in ten geographically diverse strains of H. pylori, but the Southern analysis of genomic DNA suggested that the location of the hap gene was different in each strain. We suggest that the hap gene is subject to a high rate of mutation and subsequent polymorphisms by virtue of a mobile, genetic element located upstream of the hap gene in the H. pylori genome. Simple transformation experiments suggested that this polymorphism may be mediated by a transposon-like element.

The human gastric pathogen Helicobacter pylori has a gene encoding an enzyme first classified as a mucinase in Vibrio cholerae

The human bacterial pathogen Helicobacter pylori has been suggested to be the causative agent of the most common chronic infection of man. Since its first isolation in 1982, H. pylori has been associated with gastric and duodenal ulcer disease, and more recently, gastric cancer. The proteolytic digestion of gastric mucus by this microorganism has been suggested as an important mechanism by which its pathogenicity is at least partly exerted. Here we report the detection of protease activity in H. pylori total-cell and supernatant extracts. On the basis that zinc metalloproteases are common microbial pathogenicity factors, we identified a single protein in H. pylori protein extracts with antibodies to the Pseudomonas aeruginosa elastase (a secreted zinc metalloprotease). This same protein was identified by pooled serum from patients infected with H. pylori. We used the functional and immunological relationship between the P. aeruginosa elastase and the Vibrio cholerae haemagglutinin/protease (HAP) to clone the H. pylori hap gene, which was over 99% similar to the V. cholerae hap gene in the coding region. A 4 kb DNA fragment containing the entire cloned gene was highly unstable in Escherichia coli and Bacillus subtilis cloning vectors. We also demonstrated that a hap-like gene sequence is present in all nine Helicobacter species so far discovered. The V. cholerae HAP was first classified on the basis of its mucinase activity.