Clinical Evaluation of Primary Sampling Scatter Correction for Chest Tomosynthesis

This is a study that will evaluate the utility of a scatter reduction technique in reducing dose and increasing the sensitivity of stationary digital chest tomosynthesis (s-DCT) in the detection of lung lesions.

Digital tomosynthesis is an imaging modality that produces 3D sectional information using x-ray projections acquired over a limited scanning angle. Scatter is known to be the primary source of image degradation in x-ray based imaging. The investigators have developed an approach that measures scatter through a low dose (3% of the conventional scan) scatter measurement technique. Preliminary studies have shown that scatter reduction in DCT can significantly improve quality. The approach will characterize the reader confidence in lung nodule detection in a scatter corrected chest tomosynthesis imaging approach as compared to the conventional chest tomosynthesis. Fifty (50) patients who have undergone a clinical non-contrast CT with lung nodules will be asked to have an s-DCT (scan) within 4 weeks (+/- 2 week) of their clinical CT with no intervening procedures or therapies (i.e. biopsy of lung nodules). Investigators will then perform a reader study to evaluate the radiologist reader confidence in images generated from the scatter reduction technique versus more conventional chest tomosynthesis imaging.

The study scan, s-DCT and correction scan, will be performed within two weeks of the patient's clinical evaluations by chest CT and x-ray. The study scan may be done within 2 weeks prior or two weeks following standard of care imaging. There cannot be any intervening therapies or procedures (i.e. biopsy or excision of lesions) done in between the standard of care (SOC) imaging and the s-DCT. All patients will have a breath held s-DCT scan in an anterior-posterior direction.

Readers will rate their confidence in images from the experimental modality (sDCT with scatter correction) as compared to the conventional scan (chest CT with x-ray) on a 7 point Likert scale (-3 to 3) based on ability to identify lesion(s) present comparing each modality. A value of -3 is significantly less confident in the s-DCT representation 0 is the same confidence in modalities, and 3 is significantly more confident in the s-DCT representation compared to the conventional. Each individual will have a single value per reader. Two readers compared each scan. The overall reader preference between modalities was calculated by determining the mean value.

Sensitivity will be defined as the ability of s-DCT images to detect lesions positively identified on gold standard CT images.

Inclusion Criteria: Patients with known lung lesion(s) Patients having undergone a chest CT Patients 18 years of age and older Patients able to provide informed consent Exclusion Criteria: Patients who may not fit on a 35 x 35 detector (BMI > 35) Planned procedures or therapies during study (in between SOC scans and study scan on s-DCT) (biopsy or removal of lung lesion) Any woman who is pregnant, has reason to believe she is pregnant, or is lactating

Deidentified individual data that supports the results will be shared beginning 9 to 36 months following publication provided the investigator who proposes to use the data has approval from an Institutional Review Board (IRB), Independent Ethics Committee (IEC), or Research Ethics Board (REB), as applicable, and executes a data use/sharing agreement with UNC.

The investigator who proposes to use the data has approval from an IRB, IEC, or REB, as applicable, and an executed data use/sharing agreement with UNC.