Quantitative assessment of airway-wall dimensions by computed tomography (CT) has proven to be a marker of airway-wall remodelling in chronic obstructive pulmonary disease (COPD) patients. The objective was to correlate the wall thickness of large and small airways with functional parameters of airflow obstruction in COPD patients on multi-detector (MD) CT images using a new quantification procedure from a three-dimensional (3D) approach of the bronchial tree. In 31 patients (smokers/COPD, non-smokers/controls), we quantitatively assessed contiguous MDCT cross-sections reconstructed orthogonally along the airway axis, taking the point-spread function into account to circumvent over-estimation. Wall thickness and wall percentage were measured and the per-patient mean/median correlated with FEV1 and FEV1%. A median of 619 orthogonal airway locations was assessed per patient. Mean wall percentage/mean wall thickness/median wall thickness in non-smokers (29.6%/0.69 mm/0.37 mm) was significantly different from the COPD group (38.9%/0.83 mm/0.54 mm). Correlation coefficients (r) between FEV1 or FEV1% predicted and intra-individual means of the wall percentage were -0.569 and -0.560, respectively, with p < 0.001. Depending on the parameter, they were increased for airways of 4 mm and smaller in total diameter, being -0.621 (FEV1) and -0.537 (FEV1%) with p < 0.002. The wall thickness was significantly higher in smokers than in non-smokers. In COPD patients, the wall thickness measured as a mean for a given patient correlated with the values of FEV1 and FEV1% predicted. Correlation with FEV1 was higher when only small airways were considered.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a severe disease that has been ignored for a long time. However, with the development of improved therapeutic modalities, cardiologists and thoracic surgeons have shown increasing interest in the diagnostic work-up of this entity. The diagnosis and management of chronic thromboembolic pulmonary hypertension require a multidisciplinary approach involving the specialties of pulmonary medicine, cardiology, radiology, anesthesiology and thoracic surgery. With this approach, pulmonary endarterectomy (PEA) can be performed with an acceptable mortality rate. This review article describes the developments in magnetic resonance (MR) imaging techniques for the diagnosis of chronic thromboembolic pulmonary hypertension. Techniques include contrast-enhanced MR angiography (ce-MRA), MR perfusion imaging, phase-contrast imaging of the great vessels, cine imaging of the heart and combined perfusion-ventilation MR imaging with hyperpolarized noble gases. It is anticipated that MR imaging will play a central role in the initial diagnosis and follow-up of patients with CTEPH.

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Purpose:To investigate the parallel acquisition technique sensitivity encoding incorporating temporal filtering (TSENSE) with three saturation-recovery (SR) prepared pulse sequences (SR turbo fast low-angle shot [SR-Turbo-FLASH], SR true fast imaging with steady precession [SRTrueFISP], and SR-prepared segmented echo-planar-imaging [SR-segEPI]) for semiquantitative first-pass myocardial perfusion imaging. Materials and Methods:In blood-and tissue-equivalent phantoms the relationship between signal intensity (SI) and contrast-medium concentration was evaluated for the three pulse sequences. In volunteers, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and normalized upslopes (NUS) were calculated from signal-time curves (STC). Moreover, artifacts, image noise, and overall image quality were qualitatively evaluated.Results: Phantom data showed a 40% increased linear range of the relation between SI and contrast-medium concentration with TSENSE. In volunteers, TSENSE introduced significantly residual artifacts and loss in SNR and CNR. No differences were found for NUS values with TSENSE. SR-TrueFISP yielded highest SNR, CNR, and quality scores. However, in SR-True-FISP images, darkbanding artifacts were most pronounced. NUS values obtained with SR-TrueFISP were significantly higher and with SR-segEPI significantly lower than with SR-TurboFLASH. Conclusion:Semiquantitative myocardial perfusion imaging can significantly benefit from TSENSE due to shorter acquisition times and increased linearity of the pulse sequences. Among the three pulse sequences tested, SRTrueFISP yielded best image quality. SR-segEPI proved to be an interesting alternative due to shorter acquisition times, higher linearity and fewer dark-banding artifacts.

Purpose:To compare steady-state free precession (SSFP) sequence protocols with different acquisition times (TA) and temporal resolutions (tRes) due to the implementation of a view sharing technique called shared phases for the assessment of left ventricular (LV) function by breath-hold cine magnetic resonance (MR) imaging. Materials and Methods:End-diastolic and end-systolic volumes (EDV, ESV) were measured in contiguous shortaxis slices with a thickness of 8 mm acquired in 10 healthy male volunteers. The following true fast imaging with steady-state precession (TrueFISP) sequence protocols were compared: protocol A) internal standard of reference, segmented: tRes 34.5 msec, TA 18 beats per slice; protocol B) segmented, shared phases: tRes 34.1 msec, TA 10 beats per slice; and protocol C) real-time, shared phases, parallel acquisition technique: tRes 47.3 msec, TA 24 beats for 12 slices covering the entire left ventricle. Results:Phase sharing leads to a significant decrease in EDV, stroke volume (SV), and ejection fraction (EF) (median difference -7.0 mL [*], -9.6 mL, and -3.4%, respectively, for protocol B; -15.3 mL, -13.3 mL, and -2.4% for protocol C; P ϭ 0.002, *P ϭ 0.021). The observed median difference of real-time EDV and SV estimates is of clinical relevance. Real-time cine MR imaging shows a greater variability of EDV and SV. No relevant differences in ESV were observed. Conclusion:The true cine frame duration of both shared phases sequence protocols exceeds the period of isovolumetric contraction (IVCT) of the left ventricle resulting in a systematic and significant underestimation of EDV and consequently SV and EF. SSFP sequence protocol parameters, particularly tRes and use of view sharing techniques, should therefore be known at follow-up examinations in order to be able to assess LV remodeling in patients with heart failure. CINE MAGNETIC RESONANCE (MR) imaging has beenshown to be the most accurate and reproducible method for the evaluation of cardiac ventricular volumes, function, and mass and is therefore regarded to be the standard of reference (1-4). Two different MR sequences are commonly used to assess cardiac function parameters non-invasively: segmented k-space turbo gradient echo (TGE) and steady-state free precession (SSFP) sequences.The accuracy of segmented k-space TGE sequences has been extensively evaluated, including animal experiments (5-8). The recently introduced SSFP sequences enable shorter acquisition times, allow higher in-plane resolutions, and provide better image quality (8,9). Their accuracy in determining left ventricular (LV) mass was also evaluated in animal experiments (10). Normal values were established for left and right ventricular volumes and function for both TGE as well as SSFP sequences, with SSFP sequences yielding significantly larger end-diastolic and end-systolic volumes (EDV and ESV, respectively) than TGE sequences (7,8,(11)(12)(13)(14)(15)(16)(17).Signal intensity in images acquired with SSFP sequences relies on T2/T1 ratio and does not depend on inflow...