Yoshimori Kassai

Diffusion-weighted MR imaging using FASE sequence for 3T MR system: Preliminary comparison of capability for N-stage assessment by means of diffusion-weighted MR imaging using EPI sequence, STIR FASE imaging and FDG PET/CT for non-small cell lung cancer patients.

PURPOSE To prospectively compare the diagnostic capability of diffusion-weighted MR imaging obtained with fast advantage spin-echo sequence (FASE-DWI) and echo planar imaging sequence (EPI-DWI), short inversion time inversion recovery fast advanced spin-echo (STIR FASE) imaging and FDG PET/CT for N-stage assessment of non-small cell carcinoma (NSCLC) patients. MATERIALS AND METHODS 95 consecutive operable NSCLC patients underwent STIR FASE imaging, FASE-DWI and EPI-DWI with a 3T system, integrated PET/CT, surgical treatment and pathological and follow-up examinations. Probability of lymph node metastasis was visually assessed using a 5-point visual scoring system. ROC analyses were used to compare diagnostic capability of all methods, while their diagnostic performance was also compared by means of McNemars test on a per node basis. Finally, McNemars test was also used for statistical comparison of accuracy of N-stage assessment. RESULTS Areas under the curve (Azs) for STIR FASE imaging (Az=0.95) and FASE-DWI (Az=0.92) were significantly larger than those for EPI-DWI (Az=0.78; p<0.0001 for STIR FSE imaging and FASE-DWI) and PET/CT (Az=0.85; p=0.0001 for STIR FSE imaging, p=0.03 for FASE-DWI) on a per node basis analysis. Accuracy of N-stage assessment using STIR FASE imaging (84.2% [80/95]) and FASE-DWI (83.2% [79/95]) was significantly higher than that using EPI-DWI (76.8% [73/95]; p=0.02 for STIR FASE imaging, p=0.03 for FASE-DWI) and PET/CT (73.7% [70/95]; p=0.002 for STIR FSE imaging, p=0.004 for FASE-DWI). CONCLUSION Qualitative N-stage assessments of NSCLC patients obtained with FASE-DWI as well as STIR FASE imaging are more sensitive and/or accurate than those obtained with EPI-DWI and FDG PET/CT.

3D ECG- and respiratory-gated non-contrast-enhanced (CE) perfusion MRI for postoperative lung function prediction in non-small-cell lung cancer patients: A comparison with thin-section quantitative computed tomography, dynamic CE-perfusion MRI, and perfusion scan.

To compare predictive capabilities of non‐contrast‐enhanced (CE)‐ and dynamic CE‐perfusion MRIs, thin‐section multidetector computed tomography (CT) (MDCT), and perfusion scan for postoperative lung function in non‐small cell lung cancer (NSCLC) patients.

Diagnostic performance of different imaging modalities in the assessment of distant metastasis and local recurrence of tumor in patients with non-small cell lung cancer

To compare the diagnostic performance of positron emission tomography with [18F] fluoro‐2‐deoxy‐glucose (FDG‐PET) coregistered with magnetic resonance imaging (FDG‐PET/MRI), MRI with and without diffusion‐weighted imaging (DWI), FDG‐PET fused with computed tomography (FDG‐PET/CT) with brain contrast‐enhanced (CE‐) MRI, and routine radiological examination for assessment of postoperative recurrence in nonsmall‐cell lung cancer (NSCLC) patients.

Flow-Dependent Noncontrast MR Angiography

Noncontrast MR angiography (NC-MRA) techniques such as time-of-flight (TOF) and phase contrast (PC) have been available since the early days of MRI development. However, long scan times and various artifacts have limited their use in the clinical setting over contrast-enhanced (CE) MRA techniques, introduced first around the mid-1990s. At the present time, three-dimensional (3D) TOF remains the main technique for intracranial MRA, while PC has been used as an angiogram technique as well as flow functional technique in various regions of the body. In other regions of the body like the chest, abdomen, and peripheral regions, CE MRA became the main MR technique in those areas. Rapid development of CE MRA was facilitated by various developments in system hardware, parallel imaging, sequence improvements, and the introduction of time-resolved MRA. Since the recent FDA black-box warning associated with the use of gadolinium-base contrast agent in 2007 and the risk of developing nephrogenic systemic fibrosis (NSF), there is renewed interest in NC-MRA as an alternative to CE MRA.

2111 Recent progress on non-contrast-enhanced MRA techniques

Methods All experiments were performed on 1.5-T clinical imagers. A flow-spoiled fresh blood imaging (FS-FBI) technique, ECG-gated 3D partial Fourier FSE, allows separation of arteries from veins by applying appropriate flow spoiling gradient pulses in the read-out (RO) direction. To find suitable ECG delay time, ECG-prep scan, single-slice multiple phases, is applied to acquire single shot images with different ECG delay times. The application of the ECGprep technique can be used as non-contrast time-resolved MRA like images by acquiring multiple phases across small incremental trigger delay times during the period of steep signal changes from systolic to diastolic phase. The renal artery examinations using non-contrast MRA techniques are a must for patients with renal insufficiency and vascular disease. In order to depict the multiple directional vasculatures of renal arteries, respiratory-gated balanced SSFP with an arterial spin labeling (time-spatial labeling inversion pulse; time-SLIP) technique was applied to gain superior in-flow effect using an axial scan. The marked blood by the time-SLIP traveled from the aorta to renal branches was acquired using balanced SSFP readout. The time-SLIP pulse was optimized to have good contrast between blood and background cortex and medulla. An inferior sat-band pulse was placed to eliminate venous flow.