Radiology in diffuse parenchymal lung disease and lung nodules

The Value of Low-dose Multi-slice Computed Tomography protocol of the Chest at Mzuzu Central Hospital, Malawi

Objective

To evaluate low-dose Computed Tomography (LDCT) chest vs. routine CT chest for image quality and diagnosis in suspected lung lesions, aiming to optimize LDCT protocol.

Methods

We retrospectively analyzed 85 patients with suspected lung lesions who underwent non-contrast enhanced (NCE) CT chest at Mzuzu Central Hospital from July 2023 to April 2024. The study divided patients into routine dose (43 patients, 120 kV, 300 mAs) and low-dose groups (42 patients, 120 kV with automatic tube current modulation) based on a transition point on February 16th, 2024. Both groups used filtered back projection (FBP) reconstruction with a 1mm layer thickness. Data were analyzed for signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and radiation dose parameters on AVW post-processing workstation, and for background noise and image quality on PACS.

Results

(1) Objective evaluation revealed significantly higher SNR and CNR (6.58 ± 1.70, 175.96 ± 26.06) in the routine dose group compared to the low-dose group (4.17 ± 1.02, 141.23 ± 19.04) (P < 0.001). Additionally, the routine dose group had significantly higher CTDIvol, DLP, and ED [(9.95 ± 0) mGy, (372.84 ± 25.52) mGy·cm, (5.22 ± 0.37) mSv] compared to the low-dose group [(5.76 ± 1.12) mGy, (211.48 ± 50.64) mGy·cm, (2.96 ± 0.71) mSv] (P < 0.001). (2) Subjective evaluation showed no significant difference in scoring for background noise and overall image quality between the routine dose group [(1.95 ± 0.21) points, (4.09 ± 0.42) points] and the low-dose group [(1.93 ± 0.26) points, (3.98 ± 0.34) points] (P > 0.05).

Conclusion

The image quality of LDCT protocol is comparable to that of routine dose, while radiation dose is significantly reduced. The image quality meets the requirements for imaging diagnosis of lung lesions, and this protocol can be widely promoted in clinical practice.

Diffusion lung capacity for carbon monoxide correlates with HRCT findings in patients with diffuse parenchymal lung disease

Abstract

Diffusion lung capacity for carbon monoxide correlates with HRCT findings in patients with diffuse parenchymal lung disease.

Background

Diffuse parenchymal lung diseases (DPLDs) affect the alveolar epithelium, pulmonary capillary endothelium, basement membrane, and perivascular and perilymphatic tissues. High-resolution computed tomography (HRCT) of the chest is the gold standard modality for diagnosing DPLD. Pulmonary function tests usually show a restrictive defect in spirometry. Single breath diffusion lung capacity for carbon monoxide (DLCO-SB) technique is used to assess the diffuse parenchymal lung diseases, as there is thickening of the alveolar membrane and diminished total lung capacity due to interstitial processes with severe decline in the transfer factor. The aim of this work was to correlate between Warrick’s HRCT fibrosis score and DLCO-SB in DPLD and to assess the possibility of using DLCO as an only tool to follow up DPLD to avoid repeated radiation exposure of the patients in HRCT chest (decrease need for radiological follow-up) or vice versa.

Results

This work recruited 89 patients over a period of 10 months duration, 74.2% of them were females. The Warrick’s score, ground-glass opacity, irregular pleural margin, subpleural cyst, honeycombing, and septal and subpleural lines were represented as 96.6%, 70.8%, 55.1%, 49.4%, and 48.3% respectively in HRCT of DPLD. Warrick’s score and its subscores (severity score, extent score, alveolitis score, and fibrosis score) were associated with a highly significant decrease in different pulmonary function indices (FVC, FEV1, TLC, and DLCO) with P value 0.001. A highly significant correlation between DLCO grades and total score grades was found with P value 0.001, and 86.8% of the patients with severe DLCO affection showed severe degree of total fibrosis score.

Conclusions

Both DLCO-SB and HRCT fibrosis scores were significantly correlated. Lifelong follow-up of function and structure of the lung in DPLD is needed by HRCT and DLCO. In an attempt to minimize repeated radiation exposure and reduce cost, we suggest DLCO to be used alone for longer follow-up periods rather than HRCT chest.