Recent technological and application developments in computed tomography and magnetic resonance imaging for improved pulmonary nodule detection and lung cancer staging

Abstract

This review compares the emerging technologies and approaches in the application of magnetic resonance (MR) and computed tomography (CT) imaging for the assessment of pulmonary nodules and staging of malignant findings. Included in this review is a brief definition of pulmonary nodules and an introduction to the challenges faced. We have highlighted the current status of both MR and CT for the early detection of lung nodules. Developments are detailed in this review for the management of pulmonary nodules using advanced imaging, including: dynamic imaging studies, dual energy CT, computer aided detection and diagnosis, and imaging assisted nodule biopsy approaches which have improved lung nodule detection and diagnosis rates. Recent advancements linking in vivo imaging to corresponding histological pathology are also highlighted. In vivo imaging plays a pivotal role in the clinical staging of pulmonary nodules through TNM assessment. While CT and positron emission tomography (PET)/CT are currently the most commonly clinically employed modalities for pulmonary nodule staging, studies are presented that highlight the augmentative potential of MR. LUNG CANCER remains a challenging disease to effectively identify, diagnose, and treat, as reflected by the 5-year survival rate, which remains similar to that of 15 years ago at 13%. Lung cancer frequently manifests as a peripheral lung nodule or mass. Radiologically identified lesions in the lung that are less than 30 mm in diameter are defined as pulmonary nodules, while those greater than 30 mm are termed masses (1). Both pulmonary nodules and masses present specific challenges in the evaluation of suspected lung cancer; however, the greatest impact of x-ray computed tomography (CT) and magnetic resonance imaging (MRI) developments have been on the detection and characterization of pulmonary nodules. Hence, the scope of this review will focus on the recent advances in CT and MRI of pulmonary nodules and lung cancer staging, highlighting the respective strengths and weaknesses of these modalities. X-ray chest radiography (CXR) is the most widely utilized modality for pulmonary abnormalities and disease screening, although sonography has been utilized in limited situations in the chest. In addition, positron emission tomography (PET) or PET/CT with 2-deoxy-2-[18F]fluoro-D-glucose (FDG) is currently widely utilized for differentiation of malignant lesions from benign lesions, staging of malignant tumors, and assessment of therapeutic effects after conservative therapy. The value of CT and MR for depicting structural anatomy is widely appreciated and applied clinically to noninvasively identify abnormalities and/ or disease. Recent developments of imaging techniques and processing have expanded the potential of these modalities to include combined structure and function. Recent exciting work for the detection, monitoring, characterization, and staging of pulmonary cancer nodules using imaging of both CT and MR modalities will be summarized in this review.While the overall...

Dual-energy CT imaging of thoracic malignancies

“…Despite all efforts, lung cancer remains a challenging disease to effectively identify, diagnose, and treat. Its 5-year survival rate remains similar to that of 15 years ago at 13% for all stages (clinical staging) [ 2 ] . Thus, it is imperative to develop new algorithms and techniques for the characterization of lung nodules and staging of lung cancer.…”

PET/MRI in Lung Cancer

“…There are many different dynamic MR protocols for the differential diagnosis of pulmonary nodules, with sensitivities ranging from 94%-100%, specificities ranging from 70%-96%, and accuracies greater than 94%. 37 Alper et al 38 found that early peak and maximum peak were significantly higher in malignant nodules than in benign ones. Malignant nodules less than 3 cm usually manifested with homogeneous and apparent enhancement.…”

“…45 CT has sensitivity ranging from 40%-84% and specificity of 57%-94% in the assessment of mediastinal invasion. 37 The absence of fat planes in T1W images is useful in determining invasion. STIR sequence can also depict adjacent structure invasion with marked high SI, in contrast to the routine T1W and T2W imaging.…”

Lung MRI of invasive fungal infection at 3 Tesla: evaluation of five different pulse sequences and comparison with multidetector computed tomography (MDCT)

“…Nevertheless, the major challenges to pulmonary MR imaging, caused by low proton density, susceptibility effects, and cardiac and respiratory motion artefacts, impair the image quality. Following technical advances of high-performance gradients, phased-array receiver coils and refined imaging sequences, high field MRI systems are becoming clinically available for pulmonary imaging [7]. Recent studies demonstrated its capability for imaging a variety of lung diseases compromising focal lung lesions, diffuse infiltrative lung disease and metastases [8][9][10].…”