Gregor Sommer

Preoperative staging of non-small-cell lung cancer: comparison of whole-body diffusion-weighted magnetic resonance imaging and 18F-fluorodeoxyglucose-positron emission tomography/computed tomography

AbstractObjectiveTo investigate the diagnostic value of whole-body magnetic resonance imaging (MRI) including diffusion-weighted imaging with background signal suppression (DWIBS) for preoperative assessment of non-small-cell lung cancer (NSCLC) in comparison to 18F-fluorodeoxyglucose 18FDG) positron emission tomography/computed tomography (PET/CT).MethodsThirty-three patients with suspected NSCLC were enrolled. Patients were examined before surgery with PET/CT and whole-body MRI including T1-weighted turbo spin echo (TSE), T2-weighted short tau inversion recovery (STIR) and DWIBS sequences (b = 0/800). Histological or cytological specimens were taken as standard of reference.ResultsWhole-body MRI with DWIBS as well as PET/CT provided diagnostic image quality in all cases. Sensitivity for primary tumour detection: MRI 93%, PET/CT 98%. T-staging accuracy: MRI 63%, PET/CT 56%. N-staging accuracy: MRI 66%, PET/CT 71%. UICC staging accuracy: MRI 66%, PET/CT 74%. Sensitivity for metastatic involvement of individual lymph node groups: MRI 44%, PET/CT 47%. Specificity for individual non-metastatic lymph node groups: MRI 93%, PET/CT 96%. Assessment accuracy for individual lymph node groups: MRI 85%, PET/CT 88%. Observer agreement rate for UICC staging: MRI 74%, PET/CT 90%.ConclusionWhole-body MRI with DWIBS provides comparable results to PET/CT in staging of NSCLC, but shows no superiority. Most relevant challenges for both techniques are T-staging accuracy and sensitivity for metastatic lymph node involvement.Key Points• Numerous radiological methods are available for the crucial staging of lung cancer • Whole-body DWIBS MRI provides comparable results to PET/CT in NSCLC staging. • No evident superiority of whole-body DWIBS over PET/CT in NSCLC staging. • Challenges for both techniques are T-staging and detection of small metastases.

Lung nodule detection in a high-risk population: Comparison of magnetic resonance imaging and low-dose computed tomography

OBJECTIVE To investigate the potential of MRI for lung nodule detection in a high-risk population in comparison to low-dose CT. METHODS 49 participants (31 men, 18 women, 51-71 years) of the German Lung Cancer Screening and Intervention Trial (LUSI) with a cancer-suspicious lung lesion in CT were examined with non-contrast-enhanced MRI of the lung at 1.5 T. Data were pseudonymized and presented at random order together with 30 datasets (23 in men, 7 in women, 18-64 years) from healthy volunteers. Two radiologists read the data for the presence of nodules. Sensitivity and specificity were calculated. Gold standard was either histology or long-term follow-up. Contrast-to-Noise-Ratio (CNR) was measured for all detected lesions in all MRI sequences. RESULTS Average maximum diameter of the lesions was 15 mm. Overall sensitivity and specificity of MRI were 48% (26/54) and 88% (29/33) compared to low-dose CT. Sensitivity of MRI was significantly higher for malignant nodules (78% (12.5/16)) than for benign ones (36% (13.5/38); P=0.007). There was no statistically significant difference in sensitivity between nodules (benign and malignant) larger or smaller than 10 mm (P=0.7). Inter observer agreement was 84% (κ=0.65). Lesion-to-background CNR of T2-weighted single-shot turbo-spin-echo was significantly higher for malignant nodules (89±27) than for benign ones (56±23; P=0.002). CONCLUSION The sensitivity of MRI for detection of malignant pulmonary nodules in a high-risk population is 78%. Due to its inherent soft tissue contrast, MRI is more sensitive to malignant nodules than to benign ones. MRI may therefore represent a useful test for early detection of lung cancer.

Head-to-Head Comparison of Two-Dimensional and Three-Dimensional Echocardiographic Methods for Left Atrial Chamber Quantification with Magnetic Resonance Imaging

BACKGROUND Limited data are available on the accuracy of quantification methods for left atrial (LA) volumes using two-dimensional (2D) and particularly real-time three-dimensional echocardiographic (RT3DE) methods in comparison with a reference standard. The aim of this study was to perform a head-to-head comparison between 2D and RT3DE methods with magnetic resonance imaging (MRI) as the reference standard. METHODS LA volumes derived from 2D echocardiographic methods (i.e., biplane modified Simpsons, biplane area-length, and prolate ellipse methods) and from RT3DE methods (i.e., 4D LA Analysis and QLAB) in 60 consecutive patients were compared with MRI measurements. Offline analysis time was recorded. RESULTS The biplane modified Simpsons and area-length methods showed good intraclass correlations with MRI for maximum (r = 0.70 and r = 0.69, P < .001) and minimum (r = 0.83 and r = 0.82, P < .001) volumes. Although RT3DE methods led to moderate increases in correlations for maximum (r = 0.94 and 0.70, P < .001) and minimum (r = 0.95 and r = 0.90, P < .001) volumes and narrower Bland-Altman limits of agreement than 2D echocardiographic methods, offline analysis time was higher for RT3DE (155-161 vs 103-144 sec). Compared with MRI, maximum and minimum LA volumes were underestimated by -4.7% and -8.9%, respectively, using 4D LA Analysis, by -15.7% and -14.9% using QLAB, by -12.3% and -4.4% using the biplane Simpsons method, by -13.7% and -6.8% using the area-length method, and by -48.2% and -50.5% using the prolate ellipse method. CONCLUSIONS The biplane Simpsons and area-length methods offer reasonable accuracy for LA chamber quantification across a broad range of volumes, while RT3DE methods lead to a moderate improvement in accuracy at the cost of more elaborate offline analysis.

Non-contrast-enhanced preoperative assessment of lung perfusion in patients with non-small-cell lung cancer using Fourier decomposition magnetic resonance imaging

OBJECTIVE To investigate non-contrast-enhanced Fourier decomposition MRI (FD MRI) for assessment of regional lung perfusion in patients with Non-Small-Cell Lung Cancer (NSCLC) in comparison to dynamic contrast-enhanced MRI (DCE MRI). METHODS Time-resolved non-contrast-enhanced images of the lungs were acquired prospectively in 15 patients using a 2D balanced steady-state free precession (b-SSFP) sequence. After non-rigid registration of the native image data, perfusion-weighted images were calculated by separating periodic changes of lung proton density at the cardiac frequency using FD. DCE MRI subtraction datasets were acquired as standard of reference. Both datasets were analyzed visually for perfusion defects. Then segmentation analyses were performed to describe perfusion of pulmonary lobes semi-quantitatively as percentages of total lung perfusion. Overall FD MRI perfusion signal was compared to velocity-encoded flow measurements in the pulmonary trunk as an additional fully quantitative reference. RESULTS Image quality ratings of FD MRI were significantly inferior to those of DCE MRI (P<0.0001). Sensitivity, specificity, and accuracy of FD MRI for visual detection of perfusion defects were 84%, 92%, and 91%. Semi-quantitative evaluation of lobar perfusion provided high agreement between FD MRI and DCE MRI for both entire lungs and upper lobes, but less agreement in the lower parts of both lungs. FD perfusion signal showed high linear correlation with pulmonary arterial blood flow. CONCLUSION FD MRI is a promising technique that allows for assessing regional lung perfusion in NSCLC patients without contrast media or ionizing radiation. However, for being applied in clinical routine, image quality and robustness of the technique need to be further improved.

Sliding multislice MRI for abdominal staging of patients with pelvic malignancies: A pilot study

To integrate SMS (sliding multislice imaging technique for acquiring axial images during continuous table motion) into a high‐resolution pelvic MRI protocol for additional staging of the entire abdomen within one examination.

Magnetic resonance imaging in valvular heart disease: Clinical application and current role for patient management

Noninvasive imaging provides important information on cardiac anatomy and function and is a key element in clinical management of valvular heart disease (VHD). Beside echocardiography, which is still considered the first‐line modality for assessment of valvular anatomy and longitudinal evaluation of VHD, cardiovascular magnetic resonance (CMR) has evolved during the last two decades as an essential tool for evaluation of cardiac diseases. Today, CMR not only represents the reference standard for measuring cardiac volumes, function, and mass, but also enables accurate assessment of morphology and function of cardiac valves. It can play an important role in clinical decision‐making for patients with VHD. This review addresses current applications and limitations of CMR imaging techniques that are used in VHD including cine‐balanced steady‐state free precession (b‐SSFP), phase contrast MR (pcMR), gradient‐recalled echo (GRE), and turbo‐spin echo (TSE) sequences. Moreover, it describes their application for evaluation of valvular pathologies and gives an overview on the current role of valvular CMR in patient management. J. Magn. Reson. Imaging 2012;35:1241–1252.

Assessing extracranial tumors using diffusion-weighted whole-body MRI

Diffusion-weighted magnetic resonance imaging (DWI) provides qualitative and quantitative information about the random motion of water molecules in biological tissues and is able to give functional insight into tissue architecture and pathological changes on a cellular level. This technique has the major advantages of not requiring the administration of contrast agents and not exposing the patient to ionizing radiation. Recent technological advances have led to the development of diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) that allows screening of the whole body in 25 minutes. DWI and DWIBS have both revealed great potential in the field of oncology and proved to be useful for detecting and characterizing tumors and evaluating treatment response. This article reviews the basic principles and experimental setup of DWI and DWIBS and illustrates its potential application to the assessment of extracranial tumors. In addition, current limitations and challenges of this promising imaging procedure are discussed.

Ultrafast 3D balanced steady-state free precession MRI of the lung: Assessment of anatomic details in comparison to low-dose CT

To evaluate the anatomical details offered by a new single breath‐hold ultrafast 3D balanced steady‐state free precession (uf‐bSSFP) sequence in comparison to low‐dose chest computed tomography (CT).

Novel magnetic resonance technique for functional imaging of cystic fibrosis lung disease

Lung function tests are commonly used to monitor lung disease in cystic fibrosis (CF). While practical, they cannot locate the exact origin of functional impairment. Contemporary magnetic resonance imaging (MRI) techniques provide information on the location of disease but the need for contrast agents constrains their repeated application. We examined the correlation between functional MRI, performed without administration of contrast agent, and lung clearance index (LCI) from nitrogen multiple-breath washout (N2-MBW). 40 children with CF (median (range) age 12.0 (6–18) years) and 12 healthy age-matched controls underwent functional and structural MRI and lung function tests on the same day. Functional MRI provided semiquantitative measures of perfusion (RQ) and ventilation (RFV) impairment as percentages of affected lung volume. Morphological MRI was evaluated using CF-specific scores. LCI measured global ventilation inhomogeneity. MRI detected functional impairment in CF: RFV 19–38% and RQ 16–35%. RFV and RQ correlated strongly with LCI (r=0.76, p<0.0001 and r=0.85, p<0.0001, respectively), as did total morphology score (r=0.81, p<0.0001). All indices differed significantly between patients with CF and healthy controls (p<0.001). Noninvasive functional MRI is a promising method to detect and visualise perfusion and ventilation impairment in CF without the need for contrast agents. New functional MRI without the need for contrast agents correlates strongly with ventilation inhomogeneity in CF http://ow.ly/emo930eQJ67

Magnetic resonance imaging for staging of non-small-cell lung cancer-technical advances and unmet needs.

Lung cancer has been and still is the most common cancer globally and with 1.8 million new cases in 2012 (1) makes up almost 13% of all newly diagnosed cancers. Despite substantial improvements in diagnosis, therapy, and prevention in the last decades and reduced mortality rates, lung cancer still is the most common cause of death from cancer with almost 1.6 million deaths in 2012 accounting for almost 20% of all cancer related deaths (1). With about 83%, non-small-cell lung cancer (NSCLC) is by far the most often-occurring tumor type within this group (2). Imaging has developed as an important factor for initial diagnosis, pre-interventional (i.e., non-invasive) staging and post interventional follow-up. In this editorial we will focus on the role of imaging in the context of staging of NSCLC, addressing in particular some of the most recently published data on magnetic resonance imaging (MRI) methods (3).