T2 mapping and T2* imaging in heart failure.

Cardiovascular magnetic resonance (CMR) is a versatile imaging modality that enables aetiological assessment and provides additional information to that of standard echocardiography in a significant proportion of patients with heart failure. In addition to highly accurate and reproducible assessment of ventricular volumes and replacement fibrosis, multiparametric mapping techniques have rapidly evolved to further expand the diagnostic and prognostic applications in various conditions ranging from acute inflammatory and ischaemic cardiomyopathy, to cardiac involvement in systemic diseases such as sarcoidosis and iron overload cardiomyopathy. In this review, we discuss the established role of T2* imaging and rapidly evolving clinical applications of myocardial T2 mapping as quantitative adjuncts to established qualitative imaging techniques.

Relationship between cardiac diffusion tensor imaging parameters and anthropometrics in healthy volunteers.

BACKGROUND: In vivo cardiac diffusion tensor imaging (cDTI) is uniquely capable of interrogating laminar myocardial dynamics non-invasively. A comprehensive dataset of quantative parameters and comparison with subject anthropometrics is required. METHODS: cDTI was performed at 3T with a diffusion weighted STEAM sequence. Data was acquired from the mid left ventricle in 43 subjects during the systolic and diastolic pauses. Global and regional values were determined for fractional anisotropy (FA), mean diffusivity (MD), helix angle gradient (HAg, degrees/%depth) and the secondary eigenvector angulation (E2A). Regression analysis was performed between global values and subject anthropometrics. RESULTS: All cDTI parameters displayed regional heterogeneity. The RR interval had a significant, but clinically small effect on systolic values for FA, HAg and E2A. Male sex and increasing left ventricular end diastolic volume were associated with increased systolic HAg. Diastolic HAg and systolic E2A were both directly related to left ventricular mass and body surface area. There was an inverse relationship between E2A mobility and both age and ejection fraction. CONCLUSIONS: Future interpretations of quantitative cDTI data should take into account anthropometric variations observed with patient age, body surface area and left ventricular measurements. Further work determining the impact of technical factors such as strain and SNR is required.

Magnetic resonance venous velocity mapping during intermittent pneumatic compression of the calf and foot.

OBJECTIVE: Assessment and optimization of intermittent pneumatic compression (IPC) devices for prophylaxis of deep vein thrombosis has previously used duplex ultrasound. The aim was to investigate novel magnetic resonance (MR) venous velocity mapping (VM) for IPC research and development. METHODS: Twelve normal subjects were scanned in the supine position using realtime MR VM with sequential foot and calf IPC (120 mmHg) at 1.5 T. Measurements were taken in the popliteal vein at baseline using both cuffs and each cuff individually recording 60 seconds continuously. Temporal resolution was 310 ms per independent image, at 1 × 1 mm spatial resolution. RESULTS: Peak velocity (V(p)) measurements: baseline, V(p) = 2.1 cm/second (range = 1.1-3.5); using both compression cuffs, V(p) = 41.5 cm/second (18.0-58.1); calf cuff alone, V(p) = 40.6 cm/second (18.1-62.2); foot cuff alone, V(p) = 7.9 cm/second (4.2-15.3). Flow volume measurements per compression cycle (F): baseline, F = 2.3 cm³ (0.5-11.4); both compression cuffs, F = 7.1 cm³ (2.5-24.6); calf cuff only, F = 7.1 cm³ (2.4-24.5); foot cuff only, F = 2.6 cm³ (0.9-10.7). The foot cuff contribution was insignificant when combined with the calf cuff (P < 0.01). The MR venous VM results were similar to those reported elsewhere using ultrasound. CONCLUSION: This novel technique for MR venous VM can measure the realtime variations in venous blood flow during IPC.

Inter-study reproducibility of 3D volume selective fast spin echo sequence for quantifying carotid artery wall volume in asymptomatic subjects.

PURPOSE: To determine, in asymptomatic subjects, the inter-study reproducibility of a three-dimensional (3D) volume selective fast spin echo (FSE) cardiovascular magnetic resonance sequence for the assessment of carotid artery wall volume as a measure of atheroma burden. METHODS: Inter-study reproducibility was evaluated in 16 asymptomatic volunteers (10 male, 6 female). Both carotid arteries were scanned twice with a median inter-scan time of 5 days. The images were acquired in cross-section, and the total carotid arterial wall volume (TWV) was calculated by subtraction of the total carotid lumen volume from the total outer carotid vessel volume. RESULTS: The mean carotid T1-weighted TWV for the first and second scans was 828 and 821 mm(3), respectively (mean difference 7 mm(3), p=0.45). The standard deviation (S.D.) of the differences between the measurements was 38 mm(3) yielding an inter-study coefficient of variation of 4.6%. The time for each study was approximately 30 min. For the longitudinal evaluation of carotid atheroma burden with pharmacological intervention versus placebo, 32 subjects would enable a difference of 38 mm(3) to be detected with a significance level of 5% with 80% power. CONCLUSION: Volumetric analysis with carotid CMR in asymptomatic subjects using a 3D volume-selective FSE is time-efficient with good inter-study reproducibility, and is well suited for longitudinal studies of carotid atheroma with reasonable sample sizes.

Contrast-enhanced MRI of the menisci of the knee using ultrashort echo time (UTE) pulse sequences: imaging of the red and white zones.

The objective of this study was to demonstrate the red and white zones of the meniscus of the knee using MRI. Ultrashort echo time (UTE) pulse sequences with an initial TE of 0.08 ms and later echoes at 5.95 ms, 11.08 ms and 17.70 ms were used to image the meniscus of the knee in two normal subjects before and after intravenous administration of gadodiamide. Difference images were formed by subtraction of later echo images from the first. The difference images showed obvious enhancement in an area consistent in location and dimensions with the red zone of the meniscus. Regions of interest placed within this area, central to it (corresponding to the white zone), and peripheral to it (corresponding to perimeniscal tissue) all showed increases in signal intensity after intravenous contrast administration. The greatest change in signal intensity in these regions of interest was seen with the shortest TE and in perimeniscal tissue on the original images. The increase in signal intensity was greatest in the red zone on the difference images. Using UTE pulse sequences and difference images derived from them, it is possible to visualize enhancement selectively in the red zone of the meniscus. Less obvious but significant changes in signal intensity were also present in the white zone.

Contrast enhancement of short T2 tissues using ultrashort TE (UTE) pulse sequences.

AIM: To review the effects of contrast administration on tissues with short T2s using a pulse ultrashort echo time (UTE) sequence. MATERIALS AND METHODS: Pulse sequences were implemented with echo times of 0.08 ms and three later gradient echoes. A fat-suppression option was used and later echo images were subtracted from the first echo image. Contrast enhancement with gadodiamide (0.3 mmol/kg) was used for serial studies in a volunteer. The images of 10 patients were reviewed for evidence of contrast enhancement in short T2 tissues. RESULTS: Contrast enhancement was seen in normal meninges, falx, tendons, ligaments, menisci, periosteum and cortical bone. In addition more extensive enhancement than with conventional pulse sequences was seen in meningeal disease, intervertebral disc disease, periligamentous scar tissue and periosteum after fracture. Subtraction of an image taken with a longer TE from the first image was of value in differentiating enhancement in short T2 tissues from that in long T2 tissues or blood. CONCLUSION: Contrast enhancement can be identified in tissues with short T2s using UTE pulse sequences in health and disease.

Glagov remodeling of the atherosclerotic aorta demonstrated by cardiovascular magnetic resonance: the CORDA asymptomatic subject plaque assessment research (CASPAR) project.

BACKGROUND: Aortic atherosclerosis and coronary artery disease (CAD) are closely linked. Early detection of aortic atherosclerosis with the adoption of appropriate preventive measures may therefore help to reduce mortality and morbidity related to CAD. Arterial remodeling, by which the wall adapts to physiological or pathological insults by a change in vessel size, is being increasingly recognized as an important aspect of atherosclerosis. In this prospective longitudinal study we used cardiovascular magnetic resonance (CMR) to detect aortic plaque and to study aortic wall remodeling in asymptomatic subjects. METHODS: We recruited 175 healthy volunteers (49 years, 110 men) and documented their cardiovascular risk profile. Each subject underwent echocardiogram (ECG)-gated T1-weighted spin-echo imaging of the infrarenal abdominal aorta at baseline and after 2 years. FINDINGS: Of the 175 subjects who volunteered at baseline, CMR was successful in 174 (99%), with one (0.6%) failure due to claustrophobia. At 2 years, follow-up scanning was performed in 169 subjects (97%). Infrarenal aortic plaque was identified at baseline in nine (5.2%) subjects. This was reconfirmed in all nine (100%) cases at 2-year follow-up. No new cases of infrarenal plaque were identified at follow-up. The signal characteristics of the plaque on the subtracted images of the Dixon method indicate that all plaques were fibrous. In the nine subjects with infrarenal plaque, the total plaque burden increased as assessed by the total wall volume (561 to 677 mm3, p = 0.0063). The total vessel volume also increased (1737 to 1835 mm3, p = 0.031) but there was no change in the total luminal volume (1175 to 1157 mm3, p = 0.29). CONCLUSIONS: Cardiovascular magnetic resonance detects subclinical aortic atherosclerosis, can follow plaque burden over time, and confirms the presence of Glagov remodeling with preservation of the lumen despite progression of plaque. Cardiovascular magnetic resonance is well suited for the longitudinal follow-up of the general population with atherosclerosis, may help in the understanding of the natural history of atherosclerosis, and in particular may help determine factors to retard disease progression at an early stage.

Ultrashort echo time (UTE) MRI of the spine in thalassaemia.

Back pain is common in adult patients with homozygous thalassaemia, and degenerative disc disease is increasingly recognised as a cause. Ultrashort echo time (UTE) pulse sequences, which are sensitive to the presence of short T(2) relaxation components in tissue produced by iron deposition and other processes, were used to examine the lower thoracic and lumbar spine in symptomatic patients with beta-thalassaemia major or intermedia. Three patients were studied with fat suppressed as well as both fat suppressed and long T(2) suppressed UTE (TE=0.08 ms) pulse sequences. Conventional 2D Fourier transformation T(1) and T(2) weighted scans were also performed for comparison. Normal controls showed narrow high signal areas in the region of the end-plate and annulus fibrosus. Patients showed hyperintense bands adjacent to the vertebral end plate in lower thoracic and lumbar spine discs using a UTE sequence with both long T(2) component and fat suppression. The extent of the changes was most marked in the patient with the most severe degenerative change. In the patient with minimal disease, findings of this type were present in discs which did not show evidence of degeneration with conventional MR imaging. High signal changes of a type previously not described were observed in each patient. The effect may be due to organic iron entering the disc and decreasing its T(1) and T(2), but susceptibility effects from iron in the vertebral bodies, fibrosis and other causes also need to be considered.

MRI of the brain with ultra-short echo-time pulse sequences.

As well as the long-T2 relaxation components normally detected with conventional imaging techniques, the brain has short-T2 components. We wished to use ultra-short (0.08 ms) echo time (UTE) pulse sequences to assess the feasibility of imaging these in normal subjects and patients. UTE sequences were employed, with or without fat suppression, 90 degree long-T2 suppression pulses, and selective nulling of long-T2 components using an inversion pulse. Subtraction of later echoes from the first was also used to reduce the signal from long-T2 components. We studied dive normal subjects and 15 patients with various diseases. Short-T2 components were demonstrated in grey and white matter. Increased signal from these components was seen in meningeal disease, probable calcification, presumed cavernomas, melanoma metastases and probable gliosis. Reduced signal was seen in some tumours, infarcts, mild multifocal vascular disease and vasogenic oedema. Further development and evaluation of these pulse sequences is warranted.

Magnetic resonance imaging of short T2 components in tissue.

The most widely used clinical magnetic resonance imaging techniques for the diagnosis of parenchymal disease employ heavily T(2)-weighted sequences to detect an increase or decrease in the signal from long T(2) components in tissue. Tissues also contain short T(2) components that are not detected or only poorly detected with conventional sequences. These components are the majority species in tendons, ligaments, menisci, periosteum, cortical bone and other related tissues, and the minority in many other tissues that have predominantly long T(2) components.The development and clinical application of techniques to detect short T(2) components are just beginning. Such techniques include magic angle imaging, as well as short echo time (TE), and ultrashort TE (Ute) pulse sequences. Magic angle imaging increases the T(2) of highly ordered, collagen-rich tissues such as tendons and ligaments so signal can be detected from them with conventional pulse sequences. Ute sequences detect short T(2) components before they have decayed, both in tissues with a majority of short T(2) components and those with a minority. In the latter case steps usually need to be taken to suppress the signal from the majority of long T(2) components. Fat suppression of different types may also be helpful. Once signal from short T(2) components has been detected, different pulse sequences can be used to determine increases or decreases in T(1) and T(2) and study contrast enhancement. Using these approaches, signals have been detected from normal tissues with a majority of short T(2) components such as tendons, ligaments, menisci, periosteum, cortical bone, dentine and enamel (the latter four tissues for the first time) as well as from the other tissues in which short T(2) components are a minority. Some diseases such as chronic fibrosis, gliosis, haemorrhage and calcification may increase the signal from short T(2) components while others such as loss of tissue, loss of order in tissue and an increase in water content may decrease them. Changes of these types have been demonstrated in tendonopathy, intervertebral disc disease, ligament injury, haemachromatosis, pituitary perivascular fibrosis, gliomas, multiple sclerosis and angiomas. Use of these techniques has reduced the limit of clinical detectability of short T(2) components by about two orders of magnitude from about 10 ms to about 100 micros. As a consequence it is now possible to study tissues that have a majority of short T(2) components with both "bright" and "dark" approaches, with the bright (high signal) approach offering options for developing tissue contrast of different types, as well as the potential for tissue characterization. In addition, tissues with a minority of short T(2) components may demonstrate changes in disease that are not apparent with conventional heavily T(2)-weighted sequences.

Tracking local volume 3D-echo-planar coronary artery imaging.

Aiming for robust high-resolution free respiration coronary artery imaging, localized tracking volume selective 3D-EPI at spatial resolution 1.25 x 1.25 x 3 mm and temporal resolution 65 ms was evaluated in 14 normal subjects. Subject-specific motion tracking factors were measured between diaphragm navigator and coronary artery in S-I and A-P directions. Imaging was repeated with and without tracking, accepting 128 cardiac cycles over a 20-mm range from free breathing. Reference images with minimal respiratory motion (5-mm range) used LED-guided multiple breathholds. Depending on accurate motion measurement, coronary arteries were imaged with tracking, in a 20-mm range of free breathing, with increased scan efficiency but without significant loss of image quality compared to multiple breathhold imaging.

Echo-planar magnetic resonance myocardial perfusion imaging: parametric map analysis and comparison with thallium SPECT.

Magnetic resonance (MR) perfusion FLASH imaging has been used for assessing coronary artery disease (CAD). Echo-planar MR techniques have advantages in speed and in making MR perfusion imaging results more clinically accessible through parametric maps, but have not been previously assessed. We implemented a spin-echo, echo-planar MR technique and applied it at rest and during adenosine stress in 26 patients with CAD and abnormal thallium single-photon-emission computed tomography (SPECT), and analyzed the results by using a newly developed parametric map analysis of time to peak, peak intensity, and slope of contrast washin. The results were compared with the results of conventional visual analysis of the perfusion cine series. For detecting abnormal coronary territories, MR and SPECT were comparable for sensitivity, specificity, and accuracy (thallium, 70%, 78%, and 73%; MR, 79% 83%, and 80%; P = NS). There was good agreement between thallium and MR during stress (kappa = 0.49), but defects were larger by MR (2.4 vs. 3.1 segments for slope; P < 0.01). Additional segments were detected at rest by MR (58 for slope vs. 25 for thallium), which correlated with areas that became abnormal with stress in the thallium (sensitivity, 100%; specificity, 63%). The parametric maps were easier and faster to interpret than review of the original first-pass series of images (chi2 = 10.8; P < 0.04). The diagnostic performance of echo-planar perfusion MR and SPECT was similar, and combining the results with parametric mapping was useful for interpretation and considerably improved data display for clinical interpretation. MR, however, was faster and yielded images of higher resolution with no radiation burden. In multislice mode, these new MR techniques may have clinical value.

Anomalous coronary arteries: anatomic and functional assessment by coronary and perfusion cardiovascular magnetic resonance in three sisters.

Combined coronary and perfusion cardiovascular magnetic resonance was performed in three sisters with angina and suspected anomalous coronary arteries. Two sisters had anomalous coronary arteries passing between the aorta and right ventricular outflow tract and had abnormal myocardial perfusion. One sister had normal anatomy and perfusion. The combined approach identified the anatomy and functional significance of suspected anomalous coronary arteries.

The cardiovascular magnetic resonance machine: hardware and software requirements.

The flexibility of cardiac magnetic resonance imaging (MRI) includes faster imaging for applications such as stress tests, ventricular function, myocardial perfusion and coronary artery imaging. Faster imaging makes greater demands on the hardware and software. Although some cardiac imaging can be performed at 0.5 T, some of the faster techniques demand the higher signal-to-noise ratio of higher main field, and fat suppression in cardiac images is more easily achieved at higher field. Main field inhomogeneity affects rapid imaging and performance in open-access magnets. High gradient performance, low eddy currents and surface receiver coils are essential for fast cardiac imaging and the hardware of these systems including interventional imaging is discussed. The use of ECG signals for prospective and retrospective cardiac synchronization of MRI is examined. Techniques for reducing the major problem of respiratory motion in MRI are surveyed. Flexibility in the computer architecture of the scanner and the electronics generating the pulse sequence and controlling data acquisition is vital in cardiac imaging, for retrospective cardiac gating, respiratory navigator-controlled imaging and "real-time interactive" imaging in a similar manner to ultrasound imaging. Automated measurements from MR images remain under development. The pulse sequences and image display functions a cardiovascular MRI system should support for basic cardiac imaging applications and current clinical research areas are summarized.

A comparison between segmented k-space FLASH and interleaved spiral MR coronary angiography sequences.

A direct comparison of segmented fast low-angle short (FLASH) imaging and interleaved spiral magnetic resonance coronary angiography (MRCA) during free respiration using navigator echo has been performed. MRCA images were acquired in 30 normal subjects and 15 patients with coronary artery disease (CAD). Images of the right coronary artery were acquired during free respiration using navigator echo gating for both a segmented k-space FLASH sequence (8 views/segment, segment duration 105 msec) and an interleaved spiral sequence (20 interleaves, spiral read-out period 19 msec). Image quality was scored by three independent blinded observers, and coronary artery signal-to-noise ratio (SNR) and coronary artery/epicardial fat contrast-to-noise ratio (CNR) were measured. There was a significant improvement in image quality when coronary images were acquired with the interleaved spiral sequence (spiral 2. 3 vs. FLASH 1.8; P = 0.002). This was associated with an increase in the coronary artery SNR (16.6 +/- 6.9 vs. 11.8 +/- 5.0; P < 0.001), the coronary artery/epicardial fat CNR (12.5 +/- 6.1 vs. 7.4 +/- 4.0, P < 0.001), and the image resolution (256 x 256 vs. 256 x 128). However, there was a 12% increase in acquisition time for the interleaved spiral sequence. Image quality, SNR, CNR, and resolution can be improved using an interleaved spiral sequence. These improvements are secondary to the intrinsic characteristics of spiral imaging and the short acquisition period, which reduces the effects of both cardiac and respiratory motion.

Left ventricular quantification in heart failure by cardiovascular MR using prospective respiratory navigator gating: comparison with breath-hold acquisition.

Cardiovascular magnetic resonance (CMR) is the reference standard for the assessment of cardiac function. Faster sequences, such as breath-hold (BH) fast low-angle shot, have made CMR more clinically acceptable and cost effective. In a significantly large patient group, however, holding their breath is difficult, resulting in poor-quality images. We compared prospective navigator-echo respiratory gating (NE), which allows image acquisition during free breathing, and BH imaging in 14 patients with heart failure and 10 normal volunteers. There was good agreement between both NE and BH volumes, mass, and ejection fraction. The image quality of both NE basal and apical slices was significantly better than the corresponding BH slices in both the heart failure (P < 0.01) and normal groups (P < 0.05). The NE image acquisition was more time efficient than the BH acquisition in the heart failure group (P < 0. 01), with no difference in the normal group (P = 0.2). Thus, prospective navigator-echo gating, previously only described in coronary artery imaging, can be used in the assessment of cardiac function. It is particularly useful in patients who find it difficult to hold their breath in whom NE provides good-quality, time-efficient images.

Coronary artery imaging in grown up congenital heart disease: complementary role of magnetic resonance and x-ray coronary angiography.

BACKGROUND: There is a high incidence of anomalous coronary arteries in subjects with congenital heart disease. These abnormalities can be responsible for myocardial ischemia and sudden death or be damaged during surgical intervention. It can be difficult to define the proximal course of anomalous coronary arteries with the use of conventional x-ray coronary angiography. Magnetic resonance coronary angiography (MRCA) has been shown to be useful in the assessment of the 3-dimensional relationship between the coronary arteries and the great vessels in subjects with normal cardiac morphology but has not been used in patients with congenital heart disease. METHODS AND RESULTS: Twenty-five adults with various congenital heart abnormalities were studied. X-ray coronary angiography and respiratory-gated MRCA were performed in all subjects. Coronary artery origin and proximal course were assessed for each imaging modality by separate, blinded investigators. Images were then compared, and a consensus diagnosis was reached. With the consensus readings for both magnetic resonance and x-ray coronary angiography, it was possible to identify the origin and course of the proximal coronary arteries in all 25 subjects: 16 with coronary anomalies and 9 with normal coronary arteries. Respiratory-gated MRCA had an accuracy of 92%, a sensitivity of 88%, and a specificity of 100% for the detection of abnormal coronary arteries. The MRCA results were more likely to agree with the consensus for definition of the proximal course of the coronary arteries (P<0.02). CONCLUSIONS: For the assessment of anomalous coronary artery anatomy in patients with congenital heart disease, the use of the combination of MRCA with x-ray coronary angiography improves the definition of the proximal coronary artery course. MRCA provides correct spatial relationships, whereas x-ray angiography provides a view of the entire coronary length and its peripheral run-off. Furthermore, respiratory-gated MRCA can be performed without breath holding and with only limited subject cooperation.

Phase ordering with automatic window selection (PAWS): a novel motion-resistant technique for 3D coronary imaging.

Navigator acceptance imaging methods are hindered by the loss in scan efficiency which results from the changes in the breathing pattern of a subject over time. The diminishing variance algorithm (DVA), which does not use a predefined acceptance window, is less influenced by such changes. The use of phase ordering and weighting techniques has been shown to significantly improve image quality over nonordered window methods. However, the use of an acceptance window is inherent in all these techniques as a decision to accept or reject data must still be made. A technique is presented which is resistant to changes in breathing while allowing the use of phase ordering to provide effective motion artifact reduction in optimal time. The basic principle is described and illustrated for this automatic window-selection technique with in vitro results to demonstrate the feasibility of this method. Results of an in vivo study are also presented which demonstrate significant improvement in image quality over the DVA (p < 0.01) and hybrid-ordered phase encoding methods (p < 0.05).

Evaluation of patients undergoing lung volume reduction surgery: ancillary information available from computed tomography.

AIM: A number of imaging techniques have been used for the pre-operative assessment of patients for lung volume reduction surgery (LVRS). We evaluated whether data currently acquired from perfusion scintigrams and cine MR of the diaphragm are obtainable from high resolution CT (HRCT) of the thorax. MATERIALS AND METHODS: Thirty patients taking part in a randomized controlled trial of LVRS against maximal medical therapy were evaluated. HRCT examinations (n= 30) were scored for (i) the extent and distribution of emphysema; (ii) the extent of normal pulmonary vasculature; and (iii) diaphragmatic contour, apparent defects and herniation. On scintigraphy, (n= 28), perfusion of the lower thirds of both lungs, as a proportion of total lung perfusion (LZ/T(PERF)), was expressed as a percentage of predicted values (derived from 10 normal control subjects). On cine MR (n= 25) hemidiaphragmatic excursion and coordination were recorded. RESULTS: Extensive emphysema was present on HRCT (60% +/- 13.2%). There was strong correlation between the extent of normal pulmonary vasculature on HRCT and on perfusion scanning (r(s)= 0.85, P< 0.00005). Hemidiaphragmatic incoordination on MR was weakly associated with hemidiaphragmatic eventration on HRCT (P= 0.04). CONCLUSION: The strong correlation between lung perfusion assessed by HRCT and lung perfusion on scintigraphy suggests that perfusion scintigraphy is superfluous in the pre-operative evaluation of patients with emphysema for LVRS.

First-pass myocardial perfusion imaging and equilibrium signal changes using the intravascular contrast agent NC100150 injection.

In this phase I clinical study, the new ultrasmall superparamagnetic iron oxide contrast agent, NC100150 Injection (Nycomed AS, Oslo, Norway, a part of Nycomed Amersham), was assessed for first-pass magnetic resonance myocardial perfusion studies and its ability to produce equilibrium signal changes, as a possible indicator of myocardial blood volume. Data were acquired in 18 healthy male volunteers at 0.5 T and 1.5 T. At both field strengths, first-pass studies using T1-weighted sequences were acquired. Long TE spin-echo echoplanar imaging (EPI) was used at 0.5 T and short TE fast low-angle shot (FLASH) imaging at 1.5 T. With both sequences, T1 effects dominated the images for low doses, and time intensity curves potentially suitable for perfusion analysis were generated. At higher doses, T2 and T2* effects were observed. At 1.5 T, these predominantly affected the blood pool signal; however, at 0.5 T the myocardial signal was also involved, reflecting the relative T2 and T2* sensitivity of the spin-echo EPI sequence as a result of the long TE and long readout window, respectively. Equilibrium changes were assessed at both field strengths using T1-weighted FLASH sequences and in addition at 1.5 T using T2*-weighted gradient-echo EPI. With the T1-weighted images at both field strengths, signal changes were observed in all subjects; however, no dose-response relationship could be shown. With the T2*-weighted EPI there was significantly lower signal (P < 0.05) with the 3 and 4 mg/kg doses than with the 2 mg/kg dose. In conclusion, NC100150 Injection is useful for first-pass myocardial perfusion using T1-weighted sequences; however, low doses in combination with short TE sequences are required to minimize sensitivity to T2* effects. Equilibrium signal changes can also be induced in the myocardium. More work is required to optimize the imaging sequences and dose of NC100150 Injection for first-pass studies and also to determine whether the equilibrium signal changes can be used to measure myocardial blood volume changes in ischemic heart disease.