Evolution of pulmonary perfusion defects demonstrated with contrast-enhanced dynamic MR perfusion imaging

Howarth, Nigel; Béziat, C.; Berthezène, Yves

doi:10.1007/s003300050886

Cited by 4 publications

(5 citation statements)

References 6 publications

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“…Kacl et al reported on dynamic MRI in four patients with sarcomas of the pulmonary arteries and found a ‘considerable variability’ of the contrast enhancement, which was interpreted as being dependent on the degree of differentiation [22]. Howarth et al described a single case in which an MRI first-pass perfusion sequence was used to prove the vascularization of the lesion [23]. Fasse et al reported on MDCT and MRI findings in five patients with sarcomas of the pulmonary arteries and found only MR imaging suitable for the evaluation of lesion enhancement [8].…”

Section: Discussionmentioning

confidence: 99%

Imaging features of primary Sarcomas of the great vessels in CT, MRI and PET/CT: a single-center experience

et al. 2013

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BackgroundTo investigate the imaging features of primary sarcomas of the great vessels in CT, MRI and 18 F-FDG PET/CT.MethodsThirteen patients with a primary sarcoma of the great vessels were retrospectively evaluated. All available images studies including F-18 FDG PET(/CT) (n = 4), MDCT (n = 12) and MRI (n = 6) were evaluated and indicative image features of this rare tumor entity were identified.ResultsThe median interval between the first imaging study and the final diagnosis was 11 weeks (0–12 weeks). The most frequently observed imaging findings suggestive of malignant disease in patients with sarcomas of the pulmonary arteries were a large filling defect with vascular distension, unilaterality and a lack of improvement despite effective anticoagulation. In patients with aortic sarcomas we most frequently observed a pedunculated appearance and an atypical location of the filling defect. The F-18 FDG PET(/CT) examinations demonstrated an unequivocal hypermetabolism of the lesion in all cases (4/4). MRI proved lesion vascularization in 5/6 cases.ConclusionIntravascular unilateral or atypically located filling defects of the great vessels with vascular distension, a pedunculated shape and lack of improvement despite effective anticoagulation are suspicious for primary sarcoma on MDCT or MRI. MR perfusion techniques can add information on the nature of the lesion but the findings may be subtle and equivocal. F-18 FDG PET/CT may have a potential role in these patients and may be considered as part of the imaging workup.

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Section: Discussionmentioning

confidence: 99%

Imaging features of primary Sarcomas of the great vessels in CT, MRI and PET/CT: a single-center experience

et al. 2013

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“…As an adjunct to MRA, contrast-enhanced pulmonary perfusion MRI can be used for the assessment of PE [6,7]. One of the major technical limitations of pulmonary perfusion MRI is the limited achievable SNR, caused by the low proton density and extremely heterogeneous magnetic susceptibility of lung tissue.…”

Section: Discussionmentioning

confidence: 99%

“…Contrast-enhanced pulmonary perfusion MRI is an evolving modality for the assessment of regional lung perfusion [6][7][8][9][10]. In the first clinical studies, perfusion MRI achieved a high diagnostic accuracy for the detection of perfusion abnormalities when compared to perfusion scintigraphy [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

3D pulmonary perfusion MRI and MR angiography of pulmonary embolism in pigs after a single injection of a blood pool MR contrast agent

et al. 2004

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The purpose of this study was to assess the feasibility of contrast-enhanced 3D perfusion MRI and MR angiography (MRA) of pulmonary embolism (PE) in pigs using a single injection of the blood pool contrast Gadomer. PE was induced in five domestic pigs by injection of autologous blood thrombi. Contrast-enhanced first-pass 3D perfusion MRI (TE/TR/FA: 1.0 ms/2.2 ms/40 degrees; voxel size: 1.3 x 2.5 x 4.0 mm3; TA: 1.8 s per data set) and high-resolution 3D MRA (TE/TR/FA: 1.4 ms/3.4 ms/40 degrees; voxel size: 0.8 x 1.0 x 1.6 mm3) was performed during and after a single injection of 0.1 mmol/kg body weight of Gadomer. Image data were compared to pre-embolism Gd-DTPA-enhanced MRI and post-embolism thin-section multislice CT (n = 2). SNR measurements were performed in the pulmonary arteries and lung. One animal died after induction of PE. In all other animals, perfusion MRI and MRA could be acquired after a single injection of Gadomer. At perfusion MRI, PE could be detected by typical wedge-shaped perfusion defects. While the visualization of central PE at MRA correlated well with the CT, peripheral PE were only visualized by CT. Gadomer achieved a higher peak SNR of the lungs compared to Gd-DTPA (21 +/- 8 vs. 13 +/- 3). Contrast-enhanced 3D perfusion MRI and MRA of PE can be combined using a single injection of the blood pool contrast agent Gadomer.

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“…Although the use of the notched saturation pulse may raise concerns about the signal in regions with fast flow, in our experience we did not observe any distortion of the input function. The magnetization-prepared fast gradient-echo sequences, which are commonly used in DCE-MRI of pulmonary perfusion [3,5], required long recovery times to achieve sufficient T 1 contrast. However, this limited the number of slices that could be acquired within one trigger interval.…”

Section: Discussionmentioning

confidence: 99%

“…The resulting low signalto-noise ratio (SNR) limits the application of MRI in the lungs. Recent developments in short-TE imaging sequences have overcome the T* 2 decay and made it feasible to assess pulmonary perfusion by dynamic contrast-enhanced (DCE) MRI, as used in brain perfusion studies (1,(3)(4)(5)(6)(7).…”

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confidence: 99%

Application of model‐free analysis in the MR assessment of pulmonary perfusion dynamics

Chuang

Lin

et al. 2005

Magnetic Resonance in Med

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Dynamic contrast-enhanced (DCE) MRI has been used to quantitatively evaluate pulmonary perfusion based on the assumption of a gamma-variate function and an arterial input function (AIF) for deconvolution. However, these assumptions may be too simplistic and may not be valid in pathological conditions, especially in patients with complex inflow patterns (such as in congenital heart disease). Exploratory data analysis methods make minimal assumptions on the data and could overcome these pitfalls. In this work, two temporal clustering methodsKohonen clustering network (KCN) and Fuzzy C-Means (FCM)-were concatenated to identify pixel time-course patterns. The results from seven normal volunteers show that this technique is superior for discriminating vessels and compartments in the pulmonary circulation. Patient studies with five cases of acquired or congenital pulmonary perfusion disorders demonstrate that pathologies can be highlighted in a concise map that combines information of the mean transit time (MTT) and pulmonary blood volume (PBV). The method was found to provide greater insight into the perfusion dynamics that might be over- Proper regulation of pulmonary perfusion and ventilation is required for efficient gas exchange. Therefore, it is essential to accurately estimate pulmonary perfusion to assess the pathophysiology of the lung. In current clinical practice, pulmonary perfusion is evaluated with the use of nucleotide scintigraphic methods. However, these techniques are limited by poor spatial resolution and artifacts introduced by long imaging times (1). Magnetic resonance imaging (MRI) has been demonstrated to be a promising tool for evaluating brain perfusion with a spatial resolution of less than 1.5 mm and temporal resolution of about 1 s using Gd-DTPA as a contrast agent (2). When the same strategy is extended to image pulmonary perfusion, the poor magnetic field homogeneity caused by the complex air-tissue interfaces in the lung reduces the T* 2 of the lung tissue to only a few milliseconds. The resulting low signalto-noise ratio (SNR) limits the application of MRI in the lungs. Recent developments in short-TE imaging sequences have overcome the T* 2 decay and made it feasible to assess pulmonary perfusion by dynamic contrast-enhanced (DCE) MRI, as used in brain perfusion studies (1,3-7).Assuming that the contrast agent is a nondiffusible, intravascular tracer, quantitative indices, such as the relative pulmonary blood volume (PBV), relative mean transit time (MTT), and relative pulmonary blood flow (PBF), can be derived from the time courses of signal intensity (SI) in DCE-MRI (1,8,9). To eliminate the SI change from recirculation of the tracer, the time course is fitted to an assumed bolus-shaped function (typically a gamma-variate function) before the calculation is performed. Summary parameters, such as time-to-peak and gamma-fitting parameters, can be obtained as well (10). Furthermore, to achieve the absolute quantification of PBV, PBF, and MTT, a suitable arterial input function (AIF) is ...

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Evolution of pulmonary perfusion defects demonstrated with contrast-enhanced dynamic MR perfusion imaging

Cited by 4 publications

References 6 publications

Imaging features of primary Sarcomas of the great vessels in CT, MRI and PET/CT: a single-center experience

Imaging features of primary Sarcomas of the great vessels in CT, MRI and PET/CT: a single-center experience

3D pulmonary perfusion MRI and MR angiography of pulmonary embolism in pigs after a single injection of a blood pool MR contrast agent

Application of model‐free analysis in the MR assessment of pulmonary perfusion dynamics

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