An interventional study of X-ray velocimetry analyzed by 4Dx XV Ventilation Analysis in Constrictive Bronchiolitis, sponsored by Vanderbilt University Medical Center. Completed at 1 site in United States. Open to participants aged 18 Years to 60 Years. Per ClinicalTrials.gov, last updated 2022-08-30.
Sponsored by Vanderbilt University Medical Center · Not applicable, Interventional, and Diagnostic
Constrictive bronchiolitis is an uncommon lung disease that has been described in Veterans of conflicts in Iraq and Afghanistan. Although these Veterans have evidence of constrictive bronchiolitis on lung biopsies, non-invasive tests such as pulmonary function tests (PFTs) are often normal. This study will determine whether analysis of fluoroscopy images using the 4Dx XV Ventilation Analysis software developed by 4D Medical will be able to detect constrictive bronchiolitis in Veterans better than PFTs.
Constrictive (or obliterative) bronchiolitis is a rare pulmonary disease characterized by subepithelial inflammatory and fibrotic narrowing of the bronchioles on histologic analysis, which often presents with nonspecific symptoms such as progressive dyspnea on exertion and nonproductive cough over weeks to months. Constrictive bronchiolitis may be triggered by autoimmune disease, chronic allograft rejection in lung transplant recipients, graft versus host disease in stem cell transplant recipients, viral illness, or inhaled toxins. Although pulmonary function tests (PFTs) may be helpful for the diagnosis of constrictive bronchiolitis, a study performed by King and colleagues in 2009 found that many Veterans with biopsy-proven constrictive bronchiolitis had normal PFTs. Thus, for these patients, more sensitive methods of noninvasive testing are needed.
4Dx XV Ventilation Analysis is a new imaging analysis algorithm which utilizes standard fluoroscopy to quantify ventilation with sufficient fidelity to identify regional differences. Fluoroscopic images of a single tidal breath are obtained at 5 distinct angles (direct AP, +/- 36 degrees, and +/- 72 degrees). Readouts from the 4Dx XV Ventilation Analysis include absolute value of total lung ventilation, heterogeneity of lung ventilation, a frequency distribution of lung ventilation as a line plot, and a regional map of lung ventilation. In addition, an expiratory time constant (time to exhale 63% of the tidal volume), heterogeneity of the expiratory time constant, frequency distribution of expiratory time constant as a line plot, and a regional map of expiratory time constant are also calculated. Pilot studies performed by 4D Medical show data generated by the 4Dx XV Ventilation Analysis software applied to fluoroscopy is reproducible in individuals with normal lung function and the heterogeneity index increases in individuals undergoing radiation therapy.
The investigators hypothesize that the 4Dx XV Ventilation Analysis program, when applied to standard fluoroscopic images, is more sensitive for the diagnosis of constrictive bronchiolitis than PFTs in Veterans with constrictive bronchiolitis. Specific metrics that will be evaluated with the software include ventilation heterogeneity and expiratory phase constants, among other metrics. Endpoints will be compared during tidal breathing and a full exhalation to residual volume from functional residual capacity.
360 studies on the registry are indexed under Bronchiolitis; 43 are open to participants now.
This study's enrollment of 18 is below the median of 80 across 249 interventional studies indexed under Bronchiolitis.
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Constrictive bronchiolitis arm:
Control arm:
Exclusion Criteria (for both arms)
Veterans with surgical lung biopsy-proven constrictive bronchiolitis
Diagnostic Test: X-ray velocimetry analyzed by 4Dx XV Ventilation Analysis
Control patients with minimal smoking history and no chronic lung disease or respiratory symptoms
Diagnostic Test: X-ray velocimetry analyzed by 4Dx XV Ventilation Analysis
Fluoroscopy will be performed for a complete tidal breath and full exhalation at 5 angles (AP, +/- 36 degrees from AP, and +/- 72 degrees from AP) while the patient's arms are raised overhead. 4Dx XV Ventilation Analysis software will be used to analyze these images. Both groups will also undergo pulmonary function testing and take a questionnaire regarding respiratory symptoms.
X-ray velocimetry results
Heterogeneity of ventilation as detected by X-ray velocimetry
Time frame: 1 month
Plan to share: No
This study is completed, as verified in Aug 2022. You cannot join it, but the record below documents what was studied.
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Vanderbilt University Medical Center