Company: QTIWW
Filing Date: 2025-02-05
Form Type: 424B3
Source: 0001628280-25-004061
Chunk: 211

Company: QT IMAGING HOLDINGS, INC.
Filing Date: 2025-02-05
Form: 424B3
Chunk 211
---
 to new readers reading new cases, but with wider confidence levels compared to the RRFC analysis.

For both approaches, performance comparisons between QT and FFDM were summarized in terms of mean differences between readers and 95% confidence intervals (CI) for these differences with p-values determining the degree of statistical significance. The performance metrics included non-cancer and cancer recall rates and detection rates for all lesions. In addition, the study analyzed the mean area under the receiver operator curve (ROC-AUC) based on the readers’ confidence scores as a statistically efficient approach to evaluating the cancer and noncancer performance metrics combined into a single measurement. These analyses were performed according to the method of Obuchowski & Rockette with Hillis adjustment to the degrees of freedom. The RRRC analysis of ROC-AUC was performed with the software package ORDBM MRMC 2.5, written by Stephen L, Kevin M. Schwartz, and Kevin S. Berbaum. The trapezoidal/Wilcoxon method for curve fitting and jackknifing for the covariance estimation were used in the analysis. All other statistical analyses were performed in the statistical computing environment R version 3.4.0 or higher. No statistical adjustments were made for multiple analyses. The ground truth was established by one-year follow-up mammogram results for the normal cases and pathology results for the benign and cancer cases. All RRFC and RRRC results were adjusted post-hoc for location bias, considering recalls as correct only when the decisions were based on the correct ground-truth lesions. This adjustment is indicated because the severity of location bias is dissimilar for the two imaging modalities. Therefore, the study was adjusted for location bias to avoid favoring the modality with higher false-positive rates.

Leveraging the speed of sound attribute of transmission ultrasound, the QTscan offers advantages in specificity as well. Image 9 below compares the same breast on mammography and the QTscan. While the mass may be visible in mammography, mammography cannot be specific about whether the mass is malignant or benign. The QTscan identifies the mass as a benign cyst based on speed of sound as well as morphology. 18

18 See, HealthImaging, Up-and-coming Ultrasound Technology Shows Prowess as Mammography Adjunct (May 24, 2017), available at https://healthimaging.com/topics/medical-imaging/womens-imaging/and-coming-ultrasound-technology-shows-prowess-mammography (providing a link to