Influences of scan-position on clinical ultra-high-resolution CT scanning: a preliminary study

Abstract

The aim of this study is to access influences of scan-position on clinical ultra-high-resolution CT scanning. We proposed a breath-hold assisted ultra-high-resolution scanning technology (scan scheme G) and compared with scan scheme A (regular CT plain scan) and scheme B (1024 ultra-high-resolution scan with patients stay in supine position). A total of 30 patients with fGGO were included in this study. Three highly experienced chest imaging doctors were employed to score the image and to select regions of interest (ROIs) for CT value and signal-to-noise ratio (SNR) calculation. In comparison with scan A and B, this new scan scheme G shows more clear CT images and higher SNRs at overall lung field (the p-values of A versus G and B versus G are 0.041 and 0.065, respectively). These findings suggest that scan-G provides a better image quality and contributes significantly to clinical detection accuracy of fGGO.

Ultra-High-Resolution CT Features of Pulmonary Nodules Correlate with Visceral Pleural Invasion in Early Stage Lung Adenocarcinoma

“…Electronic medical records were retrieved from the radiology picture archiving and communication system (PACS) in our hospital, and a retrospective analysis of clinical data, including CT ndings and pathology records, from January 2014 to October 2018 was performed. Inclusion criteria were as follows: (a) lung adenocarcinoma or its preinvasive lesions equal to or less than 3cm in diameter measured on chest CT imaging without distant metastases; (b) GGNs contacting the interlobar ssure; (c) surgical resection; and (d) availability of U-HRCT data with three-dimensional orthogonal post-processing (10). Excluded patients were: (a) those who had received chemotherapy, radiotherapy, or chemoradiotherapy preoperatively; (b) those with multiple primary lung cancers; (c) those without U-HRCT data.…”

“…All patients underwent breathing exercises before scanning, and all scans were performed under deep inspiration breath-hold. Considering the radiation dose, Only U-HRCT scan having better image quality and detail display ability than conventional CT was performed (10)(11)(12), the parameters were as follows: FOV 250 mm, matrix 1024×1024, lateral or oblique lateral lying position with the lesion positioned as high as possible in the scanning lung eld (the lesion and its surrounding background were in ated as much as possible by physiological breathing), scanning angle of view image (view angle) 90°, 120kV, 250mAs, reconstruction thickness 1mm / space 1mm, FBP-D reconstruction algorithm lung window (C -500HU W 1500HU); reconstruction FOV 130-250mm, reconstruction thickness 0.67mm, space 0.3mm, iDose 4 4-6, low-pass ltered smooth reconstruction of lung window (C -500HU W 1500HU).…”

Predicting the histological invasiveness of pulmonary adenocarcinoma manifesting as persistent pure ground-glass nodules by ultra-high-resolution CT target scanning in the lateral or oblique body position

“…In this context, there is a pressing need to develop a systematic method for assessing pGGNs. A modified practical technical approach [ultra-high-resolution computed tomography (U-HRCT) target scanning in the lateral or oblique body position (namely protocol G scanning)] to assess pGGNs has been proposed by an earlier investigation (26).…”

“…Compared with conventional CT, the main advantage of protocol G scanning is that it provides significantly better image quality for displaying the detailed characteristics of pGGNs through sufficient higher spatial resolution [small 250 mm field of view (FOV), 1,024×1,024 matrix, 0.24 mm pixel, and submillimeter slice thickness] and higher contrast resolution (26). The iterative reconstruction technique (iDose4) substantially reduces image noise while maintaining spatial resolution.…”

“…The iterative reconstruction technique (iDose4) substantially reduces image noise while maintaining spatial resolution. Lateral or oblique positioning may also be helpful to more fully characterize pGGNs due to hyperinflation of the ipsilateral lung rather than simple deep inspiration (26). Indeed, several previous studies have evaluated pulmonary nodules by using U-HRCT (27)(28)(29).…”