Left ventricular AV-plane displacement is preserved with lifelong endurance training and is the main determinant of maximal cardiac output.

Age-related decline in cardiac function can be prevented or postponed by lifelong endurance training. However, effects of normal ageing as well as of lifelong endurance exercise on longitudinal and radial contribution to stroke volume are unknown. The aim of this study was to determine resting longitudinal and radial pumping in elderly athletes, sedentary elderly and young sedentary subjects. Furthermore, we aimed to investigate determinants of maximal cardiac output in elderly

Gadodiamide injection for Enhancement of MRI in the CNS. Applications, dose, field and time dependence.

Aims of the study The aims of this study using Gadodiamide injection were to investigate: · Whether Gadodiamide injection was comparable to Gd-DTPA for the enhancement of CNS lesions. · The contrast effect at different field strengths. · The effective time-window for the enhancement of blood-brain barrier damage. · The relations between the concentration of contrast agent and enhancement in phantoms, and to correlate the results to doses given to patients. · The use of a higher dose in two important clinical problems; the detection of metastases in the brain, and the evaluation of patients with failed back surgery syndrome (patients with recurrent pain after surgery for lumbar disc herniation). Results and conclusions · Gadodiamide injection was comparable to Gd-DTPA with regard to both safety and diagnostic efficacy in the CNS. · The contrast effect of Gadolinium contrast agents is higher at 1.5 T than at 0.3 T both in phantoms and patients with a maximum ratio (signal lesion / signal grey matter) more than 50% higher at 1.5T. · To achieve high contrast effect, heavily T1-weighted images are also important at both field strengths, as prolonging the repetition time from 400 ms to 600 ms reduced the ratio by 15-45% depending on concentration. · The effective time-window for imaging of blood-brain barrier damage is between 2-5 and 25-30 minutes after injection and several scans can be performed without loss of enhancement. · To provide maximum detectability of blood-brain-barrier-damage in patients with brain lesions, higher doses of Gd contrast media should be useful, as the doses used clinically today do not utilize the maximum contrast effect, either at high or low field strength. However, higher doses are more important at low field strengths because the contrast effect is lower than at high field strengths. · High-dose (0.3 mmol/kg b.w.) contrast-enhanced T1-weighted spin-echo MRI with Gadodiamide injection allowed detection of significantly (p<<0.01) more and smaller metastases than standard-dose (0.1 mmol/kg b.w.) MRI at 0.3 T. High-dose contrast-enhanced MRI with Gadodiamide injection is an efficient way to improve the detection of brain metastases. This should also be true for blood-brain barrier disruptions of other causes. · High-dose (0.3 mmol/kg b.w.) contrast-enhanced T1-weighted spin-echo MRI at 0.3T did not increase the diagnostic information in patients with recurrent pain after surgery for lumbar disc herniation compared to standard-dose (0.1 mmol/kg b.w.) MRI. The high dose images were considered more informative than the standard dose images when compared in pairs but gave no additional or different diagnostic information when evaluated separately

Radiological investigation of neurofibromatosis type 2

The radiological findings in six patients fulfilling the criteria of neurofibromatosis type 2 (NF2) were reviewed. Subtle cutaneous lesions were found in three. All patients had bilateral acoustic schwannomas; two had small acoustic tumours and normal hearing. In these patients the presenting symptoms were caused by multiple intracranial meningiomas and spinal neurofibromas, respectively, whereas the remaining four patients presented with hearing loss. Two patients had other cranial nerve tumours. Three patients had rapidly growing multiple intracranial meningiomas; two had multiple spinal neurofibromas and one a spinal meningioma. NF2 is a rare disease with few cutaneous but frequent, typical radiological findings in the central nervous system. The presenting symptom is most commonly hearing loss due to acoustic schwannomas, although symptoms emanating from other intracranial or tumours are not uncommon. The discovery of multiple meningiomas or multiple spinal neurofibromas without cutaneous lesions should initiate a search for acoustic schwannomas even when the patient has normal hearing

Time-dependency in brain lesion enhancement with gadodiamide injection

PURPOSE: To determine the effective time window for MR imaging of tumors with blood-brain barrier (BBB) damage after injection of Gd-containing contrast media. MATERIAL AND METHODS: Eleven patients with 15 brain lesions (metastasis, glioma, abscess) were studied with a T1-weighted spin-echo sequence repeated over periods of up to 43 min after contrast injection. A quotient was calculated between the signals in the lesion and in the gray matter, and plotted against time. RESULTS: All lesions reached 70% of the maximum RATIO within 3.5 min. After 25 min 12 out of 15 lesions showed persistent enhancement within 15% of the maximal RATIO. CONCLUSION: The peak enhancement of BBB damage occurs around 3.5 min after injection. The effect does not change during the next 25 min. Scanning should not be started until 2-5 min after injection of the contrast medium, and there is no advantage in waiting longer as no major increase (or decline) of contrast can be expected

Brain lesion contrast in MR imaging. Dependence on field strength and concentration of gadodiamide injection in patients and phantoms

PURPOSE: To compare the contrast effects of gadodiamide injection at 0.3 and at 1.5 T, at different concentrations in phantoms, and to correlate the results to clinical doses used for examining brain lesions. MATERIAL AND METHODS: Gel phantoms with T1 and T2 corresponding to brain gray matter were doped with different concentrations of gadodiamide injection and examined with T1-weighted sequences. Two different sets of phantoms were used, one for 0.3 T and one for 1.5 T. To express contrast, a quotient (RATIOphantom) between signals in each tube with gadodiamide injection and in the one without it was calculated. A corresponding quotient (RATIOpatient) between signals in brain metastases and in gray matter was calculated in 16 patients examined at 0.3 T (0.1 and 0.3 mmol Gd/kg b.w.) and in 5 patients examined at 1.5 T (0.1 mmol Gd/kg b.w.). RESULTS: Maximum RATIOphantom and RATIOpatient were more than 50% higher at 1.5 T than at 0.3 T at equal concentrations using heavily T1-weighted sequences. The use of SE TR/TE 600/30 instead of 400/25 reduced the contrast effect 15-45% depending on concentration. Comparing RATIOpatient to RATIOphantom suggests that the maximum T1 effect of Gd contrast media occurs at higher doses than in current clinical use, as at 0.1 mmol/kg b.w. we achieved 38% (0.3 T) and 56% (1.5 T) of the maximum phantoms. At 0.3 mmol/kg b.w. we achieved 63% (0.3 T) of the theoretical maximum. CONCLUSION: The contrast effect of Gd contrast media is higher at 1.5 T than at 0.3 T. Higher doses than presently used might prove useful especially at lower field strengths where the contrast effect of Gd is less pronounced. Heavy T1-weighting is also important

Contrast-enhanced MRI of the central nervous system: comparison between gadodiamide injection and gadolinium-DTPA

Gadodiamide injection, a new nonionic, MRI contrast medium, was compared with the ionic agent gadolinium (Gd)-DTPA at 0.1 mmol/kg body weight in a double-blind, randomised trial in 60 patients, 30 receiving each substance, with known or suspected lesions of the central nervous system. The patients were closely questioned about adverse events. In the Gadodiamide injection group, four patients reported six adverse advents, three of which were judged to be related to the contrast medium. In the Gd-DTPA group, two patients each reported one adverse event, both of which had an uncertain relation to the contrast medium. All events were mild and no medical treatment was needed. No significant change in neurological findings, blood pressure, pulse rate or blood parameters were noted in any patient. Both contrast media were effective; no difference in overall efficacy or safety was observed

Hyperpolarized (3)He apparent diffusion coefficient MRI of the lung: Reproducibility and volume dependency in healthy volunteers and patients with emphysema.

PURPOSE: To measure the apparent diffusion coefficient (ADC) of hyperpolarized (HP) (3)He gas using diffusion weighted MRI in healthy volunteers and patients with emphysema and examine the reproducibility and volume dependency. MATERIALS AND METHODS: A total of eight healthy volunteers and 16 patients with emphysema were examined after inhalation of HP (3)He gas mixed with nitrogen (N(2)) during breathhold starting from functional residual capacity (FRC) in supine position. Coronal diffusion-sensitized MR images were acquired. Each subject was imaged on three separate days over a seven-day period and received two different volumes (6% and 15% of total lung capacity [TLC]) of HP (3)He each day. ADC maps and histograms were calculated. The mean and standard deviation (SD) of the ADC at different days and volumes were compared. RESULTS: The reproducibility of the mean ADC and SD over several days was good in both healthy volunteers and patients (SD range of 0.003-0.013 cm(2)/second and 0.001-0.009 cm(2)/second at 6% and 15% of TLC for healthy volunteers, and a SD range of 0.001-0.041 cm(2)/second and 0.001-0.011 cm(2)/second, respectively, for patients). A minor but significant increase in mean ADC with increased inhaled gas volume was observed in both groups. CONCLUSION: Mean ADC and SD of HP (3)He MRI is reproducible and discriminates well between healthy controls and patients with emphysema at the higher gas volume. This method is robust and may be useful to gain new insights into the pathophysiology and course of emphysema. J. Magn. Reson. Imaging 2008. (c) 2008 Wiley-Liss, Inc

Thoracic magnetic resonance venography using Gadofosveset in patients with venous pathology-A comparative study of image quality and inter-rater variability

BACKGROUND: High-quality non-invasive imaging of the deep venous system in the thorax is challenging, but nevertheless required for diagnosis of vascular pathology as well as for patient selection and preoperative planning for endovascular procedures.PURPOSE: To compare the diagnostic quality of Gadofosveset-enhanced thoracic magnetic resonance venography, seven consecutive patients with suspected or known disease affecting the central thoracic veins were compared to seven consecutive magnetic resonance venography using conventional gadolinium-based contrast agents.MATERIALS AND METHODS: Diagnostic capability, defined as the ability to assess vessel patency and pathologic conditions, for the major thoracic deep venous segments was assessed by two-independent readers. Both reviewers rated the overall subjective image quality on a four-graded scale, and inter-rater variability was analyzed using unweighted and weighted Cohen's kappa values.RESULTS: Diagnostic capability was generally considerably higher in the Gadofosveset group for all examined vessel segments. The overall images quality rating was significantly higher for the Gadofosveset group with a mean rating of 2.9 and 2.7 for the two-independent readers, compared to 1.2 and 1.0 for the control croup. Inter-rater variability showed less variability for the Gadofosveset group with a quadratic-weighted Cohen's Kappa value of 0.58 compared to 0.36 for the control group.CONCLUSION: Our results show that Gadofosveset-enhanced magnetic resonance venography of the central thoracic veins is a reliable technique in clinical routine practice that results in diagnostic images, superior to conventional gadolinium-based contrast medium

Physiological influence of basic perturbations assessed by non-invasive optical techniques in humans

New non-invasive techniques enabling frequent or continuous assessments of various pathophysiological conditions might be used to improve in-hospital outcome by enabling earlier and more reliable bedside detection of medical deterioration. In this preclinical study, three modern non-invasive optical techniques, laser Doppler imaging (LDI), near-infrared spectroscopy (NIRS), and tissue viability imaging (TVI), were all evaluated with respect to the influence of basic physiological perturbations (including local changes in arm positioning, skin temperature, and regional blood flow conditions) on quasi simultaneously obtained values of skin perfusion, muscle tissue oxygenation (StO2), and skin blood volume, recorded in eighteen healthy volunteers. Skin perfusion measured by LDI responded prominently to changes in positioning of the arm, whereas muscle StO2 measured by NIRS did not change significantly. Total haemoglobin count (HbT) measured by NIRS and blood volume estimated by TVI both increased significantly on lowering of the limb. On local cooling, the perfusion and blood volume were both found to increase considerably, while StO2 and HbT did not change. Local heating induced a more than 10-fold increase in skin perfusion and a small increase in blood volume. On progressive venoarterial occlusion, the perfusion, StO2, HbT, and blood volume values decreased, after transient increases in HbT and blood volume before full arterial occlusion occurred, and all values approached the baseline level on release of the occlusion with a slight overshoot of the StO2. The results obtained have potential bearing on future utilization of these non-invasive techniques in the management of severely injured and (or) critically ill patients