MR perfusion imaging: correlation with PET and quantitative angiography

4. Conclusions: The presented MR approach reliably identifies patients with anatomically and hemodynamically signiticant coronary artery stenoses. This is due to the fact, that the pulse sequence used produces a substantial change in signal intensity in the perfused versus poorly perfused myocardial regions. Analysis of upslope in this setting rather than of other parameters provides a very sensitive and specific measure of myocardial ischemia. As upslope is a semiquantitative measure of absolute perfusion, even patients with triple vessel disease may be evaluated using this method. This is not the case when using conventional nuclear techniques. Furthermore, the spatial resolution of the MR images permits one to resolve the subendocardial layers of the myocardium, which thus can be evaluated separately from the entire wall. Again, this is not possible using nuclear cardiology perfusion imaging. The robustness of this MR perfusion imaging approach and the fact, that most of the heart can be covered may qualify for its clinical application in the management of coronary artery diseas

Magnetic resonance imaging in pulmonary hypertension: an overview of current applications and future perspectives.

Pulmonary hypertension is an heterogeneous group of diseases characterised by increased pulmonary arterial pressures which impact on the upstream right ventricle. Pulmonary hypertension can be challenging to diagnose, classify and monitor when specific therapies are applicable. Cardiac magnetic resonance (CMR) imaging has greatly evolved in the last decades and is a promising tool to non-invasively follow pulmonary hypertension patients. CMR provides a comprehensive evaluation of the heart and is therefore the gold standard for quantification of right ventricular volumes, mass and function, which are critical for pulmonary hypertension prognosis. In addition, innovative MR techniques allow an increasingly precise evaluation of pulmonary haemodynamics and lung perfusion. This review highlights the main advantages offered by CMR in pulmonary hypertension and gives an overview of putative future applications. Although right heart catheterisation remains mandatory in the diagnostic algorithm, CMR could play an increasingly important role in the coming years in monitoring pulmonary hypertension patients

A concealed carcinoid cardiac metastasis uncovered by comprehensive cardiovascular magnetic resonance-based tissue characterization: a case report.

oai:serval.unil.ch:BIB_EFAC9560DFE5Cardiac metastases of carcinoid tumours are extremely rare, and their diagnosis poses a significant challenge. A variety of techniques has been reported in the literature for this purpose, ranging from echocardiogram to the Indium-111 Octreotide, positron emission tomography using specific tracers, and biopsy. Occasionally, the diagnosis is only made post-mortem. Recently, CMR (cardiovascular magnetic resonance) has been added to the diagnostic toolkit. This case report describes the CMR sequences that can be used to characterize cardiac metastases of carcinoid tumours. A 55-year-old woman with an antecedent history of resected carcinoid tumour of the ileocecal junction underwent whole-body In-111 Octreoscan single-photon emission computed tomography in the context of her follow-up. This raised the suspicion of pericardial involvement, which prompted a CMR study. Comprehensive CMR findings were consistent with isolated carcinoid tumour metastasis embedded within the anterior papillary muscle. We describe the CMR sequences that were used to characterize the metastasis. The rarity of cardiac metastasis of carcinoid tumour makes its diagnosis challenging and warrants a high level of clinical suspicion. Cardiovascular magnetic resonance imaging proves to be an indispensable tool in the tissue characterization of such tumours

Fluorine-19 magnetic resonance angiography of the mouse.

PURPOSE: To implement and characterize a fluorine-19 ((19)F) magnetic resonance imaging (MRI) technique and to test the hypothesis that the (19)F MRI signal in steady state after intravenous injection of a perfluoro-15-crown-5 ether (PCE) emulsion may be exploited for angiography in a pre-clinical in vivo animal study. MATERIALS AND METHODS: In vitro at 9.4T, the detection limit of the PCE emulsion at a scan time of 10 min/slice was determined, after which the T(1) and T(2) of PCE in venous blood were measured. Permission from the local animal use committee was obtained for all animal experiments. 12 µl/g of PCE emulsion was intravenously injected in 11 mice. Gradient echo (1)H and (19)F images were obtained at identical anatomical levels. Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were determined for 33 vessels in both the (19)F and (1)H images, which was followed by vessel tracking to determine the vessel conspicuity for both modalities. RESULTS: In vitro, the detection limit was ∼400 µM, while the (19)F T(1) and T(2) were 1350±40 and 25±2 ms. The (19)F MR angiograms selectively visualized the vasculature (and the liver parenchyma over time) while precisely coregistering with the (1)H images. Due to the lower SNR of (19)F compared to (1)H (17±8 vs. 83±49, p<0.001), the (19)F CNR was also lower at 15±8 vs. 52±35 (p<0.001). Vessel tracking demonstrated a significantly higher vessel sharpness in the (19)F images (66±11 vs. 56±12, p = 0.002). CONCLUSION: (19)F magnetic resonance angiography of intravenously administered perfluorocarbon emulsions is feasible for a selective and exclusive visualization of the vasculature in vivo

Case report: Acute pericarditis following hepatic microwave ablation for liver metastasis.

Hepatic microwave ablation (MWA) is a growing treatment modality in the field of primary and secondary liver cancer. One potential side effect is thermal damage to adjacent structures, including the pericardium if the hepatic lesion is located near the diaphragm. Hemorrhagic cardiac tamponade is known to be a rare but potentially life-threatening complication. Here we present the first case of cardiac complication following MWA treatment in a 55-year-old man who presented with late cardiac tamponade. Adequate and timely management is essential, and clinicians should be fully aware of the need to perform early transthoracic echocardiography to detect signs of pericardial effusion when cardiac involvement is suspected

Ascending aortic remodelling in Fabry disease after long-term enzyme replacement therapy.

Previous cross-sectional studies reported a high prevalence of ascending aorta dilations/aneurysms in male adults with Fabry disease, independently of cardiovascular risk factors. To characterise the remodelling of the ascending aorta in classic Fabry disease under long-term enzyme replacement therapy. Diameter of the ascending aorta was measured with magnetic resonance imaging at the sino-tubular junction (STJ), and proximal (pAsAo), and distal ascending aorta (dAsAo) at baseline, and after 5 and 10 years of enzyme replacement therapy in 15 adult Fabry patients (10 males; 5 females). Over a mean follow-up of 9.5 years, the annual expansion rates measured in 10 males with Fabry disease were 0.41 ± 0.16, 0.36 ± 0.25 and 0.41 ± 0.26 mm/y at the STJ, pAsAo and dAsAo, respectively. Expansion rate at the pAsAo level in male patients was significantly higher than the expected expansion projected from theoretical normal values: 0.36 ± 0.25 vs 0.13 ± 0.05, p = 0.017. In 5 females, the annual expansion rates at the STJ, pAsAo and dAsAo were 0.14 ± 0.11, 0.21 ± 0.18 and 0.26 ± 0.24 mm/y, respectively. There was no significant difference from the projected normal expansion rate at the level of the pAsAo: 0.21 ± 0.18 vs 0.13 ± 0.04, p = 0.39. Our data suggest that the remodelling of the ascending aorta is more pronounced in male patients with Fabry disease under long-term enzyme replacement therapy compared with the progression observed in a large population study

Coronary reserve in patients with aortic valve disease before and after successful aortic valve replacement

In patients with aortic valve disease and normal coronary angiograms coronary reserve was determined by the coronary sinus thermodilution technique. Three groups of patients were studied: 37 preoperative patients; 18 different patients 12.52 months after aortic valve replacement and seven control subjects with no cardiac disease. Coronary flow ratio (dipyridamole/rest) was diminished in preoperative compared with postoperative patients (1.66±0.44 vs 2.22±0.85; P<0.05) as well as with controls (2.80±0.84; P<0.01), and corresponding coronary resistance ratio (dipyridamolej rest) was higher in preoperative patients than in both other groups (0.61±0.17 vs 0.48±0.14; P<0.05 vs 0.37±0.10; P<0.01). Differences in the flow ratio, but not in the resistance ratio, were significant (P<0.05) in patients after aortic valve replacement compared with controls. Total coronary sinus blood flow at rest was elevated in preoperative compared with both postoperative patients and controls (252±99 vs 169±63; P<0.01; vs 170±35 ml.min−1, P<0.05), whereas flows after maximal vasodilation did not differ among the three groups (416± 184 vs 361 ± 150 vs 488± 235 ml.min−1). Postoperative patients showed a distinct, though not total regression of left ventricular angiographic muscle mass index and wall thickness. Nine of the 18 postoperative patients showed a normal coronary flow reserve and nine showed subnormal response. These two subgroups did not differ with respect to preoperative macroscopic and microscopic measures of hypertrophy. Thus in aortic valve disease, the reduced coronary vasodilator capacity is mainly due to an elevated coronary flow at rest, while the maximal coronary blood flow achieved is identical to that of postoperative patients and controls. With regression of left ventricular hypertrophy, flow at rest decreases and this leads to a distinct improvement of coronary flow reserv

Impact of bileaflet mitral valve prolapse on quantification of mitral regurgitation with cardiac magnetic resonance: a single-center study.

To quantify mitral regurgitation (MR) with CMR, the regurgitant volume can be calculated as the difference between the left ventricular (LV) stroke volume (SV) measured with the Simpson's method and the reference SV, i.e. the right ventricular SV (RVSV) in patients without tricuspid regurgitation. However, for patients with prominent mitral valve prolapse (MVP), the Simpson's method may underestimate the LV end-systolic volume (LVESV) as it only considers the volume located between the apex and the mitral annulus, and neglects the ventricular volume that is displaced into the left atrium but contained within the prolapsed mitral leaflets at end systole. This may lead to an underestimation of LVESV, and resulting an over-estimation of LVSV, and an over-estimation of mitral regurgitation. The aim of the present study was to assess the impact of prominent MVP on MR quantification by CMR. In patients with MVP (and no more than trace tricuspid regurgitation) MR was quantified by calculating the regurgitant volume as the difference between LVSV and RVSV. LVSV &lt;sub&gt;uncorr&lt;/sub&gt; was calculated conventionally as LV end-diastolic (LVEDV) minus LVESV. A corrected LVESV &lt;sub&gt;corr&lt;/sub&gt; was calculated as the LVESV plus the prolapsed volume, i.e. the volume between the mitral annulus and the prolapsing mitral leaflets. The 2 methods were compared with respect to the MR grading. MR grades were defined as absent or trace, mild (5-29% regurgitant fraction (RF)), moderate (30-49% RF), or severe (≥50% RF). In 35 patients (44.0 ± 23.0y, 14 males, 20 patients with MR) the prolapsed volume was 16.5 ± 8.7 ml. The 2 methods were concordant in only 12 (34%) patients, as the uncorrected method indicated a 1-grade higher MR severity in 23 (66%) patients. For the uncorrected/corrected method, the distribution of the MR grades as absent-trace (0 vs 11, respectively), mild (20 vs 18, respectively), moderate (11 vs 5, respectively), and severe (4 vs 1, respectively) was significantly different (p &lt; 0.001). In the subgroup without MR, LVSV &lt;sub&gt;corr&lt;/sub&gt; was not significantly different from RVSV (difference: 2.5 ± 4.7 ml, p = 0.11 vs 0) while a systematic overestimation was observed with LVSV &lt;sub&gt;uncorr&lt;/sub&gt; (difference: 16.9 ± 9.1 ml, p = 0.0007 vs 0). Also, RVSV was highly correlated with aortic forward flow (n = 24, R &lt;sup&gt;2&lt;/sup&gt;  = 0.97, p &lt; 0.001). For patients with severe bileaflet prolapse, the correction of the LVSV for the prolapse volume is suggested as it modified the assessment of MR severity by one grade in a large portion of patients