Lindell, Rebecca M.

Abstract PurposeTo determine the utility of GLILD CT scoring system for assessment of GLILD in patients with CVID to avoid the need for lung biopsy. MethodsThe CT scoring system was developed as a consensus based on review of literature. Two radiologists, blinded to patient clinical information, retrospectively scored CT scans of selected patients with histopathologic diagnosis of GLILD. Discrepancies were settled by a third radiologist. Inter-observer reproducibility was calculated with intra-class correlation coefficients. ResultsWe identified 25 CVID patients with histologically confirmed GLILD (12 male, 13 female). The median age was 38 years (range 12 – 72 years). Inter-observer reproducibility was 0.76 (95% CI 0.53 – 0.89). Splenomegaly/splenectomy and basilar predominant perilymphatic nodules greater than or equal to 4mm have good interobserver agreement in our CT scoring system. Discrepancy between observers occurred most often in differentiating intermediate versus high confidence diagnosis of GLILD as opposed to differentiating between low versus intermediate confidence. ConclusionGLILD CT scoring system of pulmonary disease in CVID patients can stratify patients into categories that may assist in avoiding lung biopsy for diagnosis in a subset of patients.

Purpose: The aim of this study was to evaluate the ability of computer-aided detection (CAD) and human readers to detect pulmonary nodules ≥5 mm using 100 kV ultra–low-dose computed tomography (ULDCT) utilizing a tin filter. Materials and Methods: After informed consent, 55 patients prospectively underwent standard-dose chest CT (SDCT) using 120 kV followed by ULDCT using 100 kV/tin. Reference nodules ≥5 mm were identified by a thoracic radiologist using SDCT. Four thoracic radiologists marked detected nodules on SDCT and ULDCT examinations using a dedicated computer workstation. After a 6-month memory extinction, readers were shown the same ULDCT cases with all CAD markings as well as their original detections, and characterized CAD detections as true positive or false positive. Results: Volume CT Dose index (CTDIvol) for SDCT and ULDCT were 5.3±2 and 0.4±0.2 mGy (P<0.0001), respectively. Forty-five reference nodules were detected in 30 patients. Reader sensitivity varied widely but similarly for SDCT (ranging from 45% to 87%) and ULDCT (45% to 83%). CAD sensitivity was 76% (34/45) for SDCT and 71% (32/45) for ULDCT. After CAD, reader sensitivity substantially improved by 19% and 18% for 2 readers, and remained nearly unchanged for the other 2 readers (0% and 2%), despite reader perception that many more nodules were identified with CAD. There was a mean of 2 false-positive CAD detections/case. Conclusions: ULDCT with 100 kV/tin reduced patient dose by over 90% without compromising pulmonary nodule detection sensitivity. CAD can substantially improve nodule detection sensitivity at ULDCT for some readers, maintaining interobserver performance.