pre-scan preparation and coaching of subject for 129xe mri of lung ventilation

Um fluxo de trabalho padronizado para ressonância magnética hiperpolarizada de 129Xe para estudar a função pulmonar

Hyperpolarized 129Xe MRI is an exciting tool for non-invasive, spatially-resolved characterization and quantification of specific aspects of pulmonary function1,2,3. Acquisition and reconstruction approaches similar to those used in anatomical proton MRI yield images of inhaled 129Xe in the lungs, permitting visualization of non-ventilated lung regions and region-resolved quantification of ventilation distribution4,5,6,7,8. More advanced pulse sequence and analysis techniques yield further complementary information, including quantification of gas-exchange efficacy between alveoli and pulmonary capillaries via spectroscopic MRI9,10,11,12,13 and characterization of alveolar microstructure integrity via diffusion-weighted MRI14,15,16.
Inhaled 129Xe has been proven safe and tolerable in adult and pediatric subjects, including those with pulmonary disease17,18. Measurements of lung function derived from 129Xe MRI have shown sensitivity to structural and functional alterations in many pulmonary disease contexts, including chronic obstructive pulmonary disease6,10,19, cystic fibrosis20,21,22, idiopathic pulmonary fibrosis23,24,25, and asthma7,10,26. Given the high safety and tolerability of 129Xe MRI, the lack of ionizing radiation in MRI compared with other common imaging approaches, and the high reproducibility of 129Xe MRI results27,28, 129Xe MRI holds significant promise, in particular for precise serial monitoring of individuals receiving a time course of therapy for chronic pulmonary disease.
The safety and clinical promise of 129Xe MRI have led to its FDA approval in December 2022 for lung ventilation imaging in persons aged 12 years and older29. Given this, it is anticipated that the number of research and clinical sites capable of performing 129Xe MRI (currently ~20 worldwide) will increase significantly over the coming years. As 129Xe MRI spreads to new institutions, it is important that robust methodological resources exist to allow sites to build out clinically relevant 129Xe MRI techniques quickly and to perform scans and generate results that are closely comparable with those of existing sites.
In this work, we will outline the current best practices for human hyperpolarized 129Xe MRI of lung ventilation, as agreed upon by member institutions of the 129Xe MRI Clinical Trials Consortium (Xe MRI CTC) and summarized in a recent position paper30. Topics will include the preparation of tailored pulse sequences ideal for a complete 129Xe MRI workflow, preparation, and administration of hyperpolarized 129Xe gas, an optimized workflow for human 129Xe MRI sessions, and best practices for monitoring subject safety and comfort during MRI sessions.

Autor em destaque: Padronização e melhores práticas para o avanço da imagem pulmonar usando ressonância magnética 129Xe

Aquisição de Imagens de Ressonância Magnética 129Xe Hiperpolarizadas da Ventilação Pulmonar

Our research seeks to establish Xenon MRI as a clinical tool for characterizing lung function. Xenon MRI allows us to directly visualize ventilation defects in patients with obstructive lung diseases like COPD, asthma, and cystic fibrosis. It offers information that can't be obtained from standard MRI and pulmonary function test.Xenon MRI was recently approved by the FDA for clinical evaluation of lung ventilation. This represents a culmination of a huge amount of effort by the people in our field and it's an exciting opportunity to show how Xenon MRI can improve patient care and outcomes in pulmonary disease. Xenon MRI is still a relatively new family of techniques, and standardization is still an ongoing process.This protocol distills the existing standards for Xenon ventilation MRI into a form that we hope will be useful to research in clinical sites who are trying to perform these scans for the first time. Common clinical readouts of lung function, like pulmonary function tests, only give a single number for the entire lung with no spatial information included. Xenon MRI can make regional assessments of several aspects of lung health and function, which we believe will be very useful in the clinic.Only a few institutions are currently performing Xenon MRI, but we expect there will be many more sites soon considering the recent FDA approval. We hope that this Xenon ventilation MRI protocol will serve as a blueprint for new sites and help em to ramp up their Xenon MRI operations more quickly.

Preparação pré-exame e treinamento do sujeito para RM 129Xe de ventilação pulmonar

Para começar, prepare um ou mais sacos Tedlar, contendo ar, para o sujeito praticar fora do scanner. Use um volume de ar que corresponda ao volume total de xenônio e gás tampão a ser inalado da bolsa durante o estudo real. Prepare clipes nasais para o sujeito usar durante a varredura de apneia, encaixe os clipes nasais no nariz do sujeito antes do início da pausa respiratória.Use um saco cheio de ar para cada tentativa de treinar o sujeito. Antes de produzir a bolsa, peça ao sujeito para inspirar e expirar regularmente várias vezes. Durante o procedimento, monitore o tórax do sujeito para confirmar se ele está executando as instruções corretamente.Em seguida, coloque o tubo preso ao saco de Tedlar na boca do sujeito. Segure a bolsa de tal forma que o sujeito possa inalar e abra a válvula. Peça ao sujeito para inspirar e, em seguida, peça ao sujeito para prender a respiração, dizendo: prenda a respiração.Ao praticar, aguarde uma contagem de 10 a 15 segundos, que é a quantidade aproximada de tempo necessária para que uma varredura típica de xenônio 129 decorra. Depois disso, peça para o sujeito expirar neste momento e respirar. Treine o sujeito a fazer várias inspirações profundas para uma eliminação mais rápida do xenônio 129 dos pulmões e um retorno mais rápido aos níveis normais de saturação de oxigênio.Verifique se o sujeito é capaz de executar as instruções de forma confiável e considere excluir os sujeitos que não podem fazê-lo durante as corridas práticas.

Research

JoVE Journal

Medicine

Pre-Scan Preparation and Coaching of Subject for 129Xe MRI of Lung Ventilation

Acquiring Hyperpolarized 129Xe Magnetic Resonance Images of Lung Ventilation

Hyperpolarized 129Xe MRI comprises a unique array of structural and functional lung imaging techniques. Technique standardization across sites is ...

Medicina

Preparation of MRI Scanner Room and Subject Positioning for 129Xe MRI of Lung Ventilation

Preparo da Sala do Scanner de RM e Posicionamento do Sujeito para RM 129Xe de Ventilação Pulmonar

Performing 129Xe MRI Scan of Lung Ventilation to Assess Pulmonary Function

Realização de ressonância magnética de 129Xe da ventilação pulmonar para avaliar a função pulmonar