Estimation of pulmonary motion in healthy subjects and patients with intrathoracic tumors using 3D-dynamic MRI: initial results

Our plain-English summary of Estimation of pulmonary motion in healthy subjects and patients with intrathoracic tumors using 3D-dynamic MRI: initial results, by C. Plathow, M. Schoebinger, F. Herth, et al (Korean Journal of Radiology, 2009).

The study

• Authors: C. Plathow, M. Schoebinger, F. Herth, S. Tuengerthal, H.P. Meinzer, H.U. Kauczor
• Journal: Korean Journal of Radiology
• Published: 2009;10(6):559-67
• Cited by: 18 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objective: To estimate a new technique for quantifying regional lung motion using 3D-MRI in healthy volunteers and to apply the technique in patients with intra- or extrapulmonary tumors.

Materials And Methods: Intraparenchymal lung motion during a whole breathing cycle was quantified in 30 healthy volunteers using 3D-dynamic MRI (FLASH [fast low angle shot] 3D, TRICKS [time-resolved interpolated contrast kinetics]). Qualitative and quantitative vector color maps and cumulative histograms were performed using an introduced semiautomatic algorithm. An analysis of lung motion was performed and correlated with an established 2D-MRI technique for verification. As a proof of concept, the technique was applied in five patients with non-small cell lung cancer (NSCLC) and 5 patients with malignant pleural mesothelioma (MPM).

Results: The correlation between intraparenchymal lung motion of the basal lung parts and the 2D-MRI technique was significant (r = 0.89, p < 0.05). Also, the vector color maps quantitatively illustrated regional lung motion in all healthy volunteers. No differences were observed between both hemithoraces, which was verified by cumulative histograms. The patients with NSCLC showed a local lack of lung motion in the area of the tumor. In the patients with MPM, there was global diminished motion of the tumor bearing hemithorax, which improved significantly after chemotherapy (CHT) (assessed by the 2D- and 3D-techniques) (p < 0.01). Using global spirometry, an improvement could also be shown (vital capacity 2.9 +/- 0.5 versus 3.4 L +/- 0.6, FEV1 0.9 +/- 0.2 versus 1.4 +/- 0.2 L) after CHT, but this improvement was not significant.

Conclusion: A 3D-dynamic MRI is able to quantify intraparenchymal lung motion. Local and global parenchymal pathologies can be precisely located and might be a new tool used to quantify even slight changes in lung motion (e.g. in therapy monitoring, follow-up studies or even benign lung diseases).

In plain English

This was a small technical study from Germany testing a new way to measure how lung tissue moves during breathing, using three-dimensional (3D) dynamic MRI and a semi-automatic computer method. It did not study asbestos exposure. The authors scanned 30 healthy non-smoking volunteers, five patients with stage I non-small cell lung cancer, and five patients with stage II malignant pleural mesothelioma. The mesothelioma patients were scanned before chemotherapy (pemetrexed and cisplatin) and after three of six cycles. In healthy volunteers, maximum motion of the lower lung was 9.2 ± 3.1 cm by the new 3D method and 8.8 ± 3.5 cm by an established 2D MRI method, and the two methods correlated (r = 0.89, p < 0.05). In the lung cancer patients, lung motion appeared restricted around the tumor. In the mesothelioma patients, the tumor-side lower lung moved 2.5 ± 1.1 cm by 3D MRI before chemotherapy and 4.5 ± 1.5 cm after. The article calls this change significant, but its table gives p = 0.08 for the 3D method. Breathing tests (spirometry) also improved, but not significantly. The authors concluded that 3D-dynamic MRI can quantify lung motion. They noted that the method infers internal motion from the lung surface and captures only one image per second.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Proof-of-principle imaging technique study: a new 3D-dynamic MRI method was compared with an established 2D-dynamic MRI method in healthy volunteers, then applied to small groups of tumor patients
• Who was studied: 30 healthy non-smoking volunteers (25 young, median age 28; 5 elderly, median age 61), 5 patients with histologically proven stage I non-small cell lung cancer (median age 63), and 5 patients with histologically proven stage II malignant pleural mesothelioma (3 male, 2 female; median age 60). The authors' institutions are in Germany; study dates are not given.
• Exposure: No asbestos or fiber exposure was studied. The variable followed over time in the mesothelioma patients was chemotherapy with pemetrexed and cisplatin; they were imaged before chemotherapy and after three of six cycles (9 weeks).
• Main results:
  • In healthy volunteers, maximum motion of the basal (lower) lung parts was 9.2 ± 3.1 cm by 3D MRI, with no significant difference between the two sides of the chest.
  • In healthy volunteers, the 2D MRI method gave maximum craniocaudal (top-to-bottom) motion of 8.8 ± 3.5 cm, and the 3D and 2D measurements were significantly correlated (r = 0.89, p < 0.05).
  • There was no significant difference in lung motion between younger and older healthy volunteers (p = 0.31).
  • In the non-small cell lung cancer patients, a substantial restriction of lung motion around the tumor was observed on the images. Table values for the tumor side were 7.8 ± 3.5 cm (2D) and 7.5 ± 3.1 cm (3D), compared with 8.5 ± 3.1 cm and 8.2 ± 3.4 cm on the healthy side; no significance test is reported for this comparison.
  • In the mesothelioma patients, maximum motion of the basal lung on the tumor side was 2.6 ± 1.0 cm (2D) and 2.5 ± 1.1 cm (3D) before chemotherapy, and 4.3 ± 1.6 cm (2D) and 4.5 ± 1.5 cm (3D) after. The table marks this as a significant change, but its footnote gives p = 0.009 for 2D MRI and p = 0.08 for 3D MRI.
  • In the mesothelioma patients, spirometry also improved after chemotherapy (vital capacity 2.9 ± 0.5 versus 3.4 ± 0.6 L; FEV1 0.9 ± 0.2 versus 1.4 ± 0.2 L), but the improvement was not significant.
• The authors' conclusion: The authors concluded that dynamic 3D-MRI with their post-processing technique is usable for quantifying lung tissue motion. They said it can show differences between healthy volunteers and patients with intra- and extrathoracic lung diseases, and might have potential for investigating slight changes in lung mechanics.
• Limitations the authors state:
  • Motion inside the lung is estimated by interpolating from motion at the lung surface.
  • The 3D method has limited temporal resolution (one image per second) and depends on the patient breathing as instructed.
  • Whether the method is sensitive enough to predict therapy response in a larger group of patients still needs to be proven.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Intrathoracic, Non-Small Cell Lung Cancer, Pleural Mesothelioma, Hemithorax, Chemotherapy, Spirometry, FEV1.

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