Clubbing due to peripheral hypervascularization: recognition by contrast-enhanced, three-dimensional magnetic resonance angiography.
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
W Kenn
Publications and source records attributed to W Kenn.
Optimization of ECG-triggered 3D (23)Na MRI of the human heart.
(23)Na MRI may allow distinction of normal and ischemically injured myocardium. The aim of this study was to optimize (23)Na MRI of the human heart by improvement of spatial resolution and ECG-triggering and to measure the signal/noise of blood and myocardium and the myocardium/blood signal ratios in a volunteer study. A spoiled gradient echo sequence was developed on a 1.5T scanner equipped with a (23)Na heart surface coil. 3D short axis ECG-triggered (23)Na MRI was performed in 10 healthy subjects. The signal/noise of myocardium and blood were 8.2 +/- 0.7 and 18.3 +/- 1.3, respectively, signal ratio myocardium/blood was 0.44 +/- 0.03. This value is in good agreement with the theoretical value of 0.45. ECG gated 3D (23)Na MRI of the human heart is feasible with sufficient spatial resolution and signal/noise ratio. Magn Reson Med 45:164-166, 2001.
Adult↗
Time course of contrast enhancement patterns after Gd-BOPTA in correlation to myocardial infarction and viability: a feasibility study.
Our objective was to analyze contrast enhancement patterns (CEP) and their time course after myocardial infarction (MI) following injection of Gd-BOPTA in correlation with recovery of regional function. Seven patients with subacute MI (18 +/- nine days) were examined before, as well as three and six (n = six) months after, revascularization of the infarct-related artery. Regional wall motion abnormalities were assessed by cine-MRI, and repetitive images of one representative slice were acquired up to 45 minutes after 0.05 mmol/kg Gd-BOPTA using a T1-w TSE-sequence. Two patients showed mid-wall/subendocardial, one patient subendocardial enhancement of MI associated with mechanical improvement after revascularization. Three patients without improvement revealed a mid-wall hypoenhanced zone within the first five minutes after injection, which was unchanged at follow-up. One patient with partial functional improvement showed transmural enhancement and a mid-wall hypoenhanced zone in adjacent areas. With this feasibility study, we concluded that mid-wall and/or subendocardial enhancement after Gd-BOPTA was associated with viable myocardium, whereas detection of microvascular obstruction correlating with scar formation is suggested by mid-wall hypoenhancement within the first five minutes after injection.
Adult↗
(31)P-MR Spectroscopy for the evaluation of energy metabolism in intact residual myocardium after acute myocardial infarction in humans.
OBJECTIVE: Experimental studies have demonstrated that acute myocardial infarction (MI) alters energy metabolism even in non-infarcted adjacent tissue. In patients with subacute MI, the influence of the regional ischemic insult on energy metabolism of intact septal myocardium was analyzed using 31P-Magnetic resonance spectroscopy (MRS). PATIENTS AND METHODS: In eight patients with wall motion abnormalities in the anterior wall 31P-spectra were obtained from non-infarcted adjacent septal myocardium, as well as infarcted anterior myocardium (voxel size 25 ccm each) 29+/-8 days after MI using a 3D-CSI technique. Additionally, cardiac function was analyzed using breath-hold cine MRI. MRI was repeated 6 months after revascularization to assess viability of infarcted segments. Eight age-matched healthy volunteers served as control group. RESULTS: According to follow-up MRI 4/8 patients showed regional wall motion recovery. Here, PCr/ATP-ratios were not significantly reduced in intact septal myocardium as well as infarcted anterior myocardium compared to healthy volunteers (1.28+/-0.10 and 1.14+/-0.09 vs. 1.45+/-0.29). No recovery of regional function was detected in 4/8 patients with-therefore-non-viable anterior myocardium. PCr/ATP-ratios were significantly reduced in intact and infarcted myocardium compared with healthy volunteers as well as to patients with wall motion recovery (0.77+/-0.17 and 0.49+/-0.23; P<0.05). DISCUSSION: These preliminary results indicate that energy metabolism is reduced in patients with persisting wall motion abnormalities after myocardial infarction and revascularization in ischemically injured as well as in adjacent non-injured myocardium.
Aged↗
[MRI of the shoulder. Degenerative changes and rotator cuff tears].
MRI currently offers the best imaging information for the diagnosis of subacromial pain syndrome, rotator cuff tears and osteoarthritis of the shoulder. The excellent anatomical and tissue specific imaging allows a detailed evaluation of the rotator cuff as well as the adjacent bony structures. If the cause of subacromial pain can not be determined despite extensive clinical, sonographical and radiological examination, MRI is indicated if there is a suspected pathology of the bony structures or the glenohumeral joint that could influence the further therapeutic procedures. In addition, MRI evaluation of muscular atrophy has become an important factor for determining appropriate therapy, particularly in cases of massive rotator cuff tears.
Acromion↗
Breath-hold 3D MR coronary angiography with a new intravascular contrast agent (feruglose)--first clinical experiences.
Demonstration of the initial results of breath-hold 3D MR coronary angiography with patients using a new intravascular contrast agent (feruglose). Contrast-enhanced 3D MR-coronary angiography was performed in 5 patients with coronary artery disease after administration of feruglose in three different doses (0.5 (n = 3), 2, 5 mg Fe/kg body weight for each patient). MR coronary angiography was performed with an ECG-triggered 3D-FLASH-sequence during breath-hold at 1.5 T (TR 6.8 ms, TE 2.5 ms, flip-angle 30 degrees ). To reduce data acquisition time, only the two anterior elements of the phased-array body coil were activated. The data acquisition window within the cardiac cycle ranged between 217-326 ms depending on the matrix. Signal-to-noise (SNR) and contrast-to-noise ratios (CNR) of the coronary arteries were analyzed, and the results for the detection of coronary artery stenoses were compared with those obtained by conventional coronary angiography. SNR and CNR revealed an improved image quality at a dose of 2 mg Fe/kg compared with the lower dose, but no further improvement was obtained by rising the dose to 5 mg Fe/kg. Except for the left circumflex artery of one patient, at minimum the proximal parts of all four main coronary arteries could be imaged for all patients. Within the visible parts of the coronary arteries, six of eight significant coronary stenoses were identified correctly. Imaging of the proximal parts of the coronary arteries including detection of stenoses is possible during breath-hold using an intravascular contrast agent.
Aged↗
Pregnancy-associated diffuse cavernous hemangioma of the uterus.
Explore the source record for details and available documents.
Adult↗
Cardiac metabolism and function in patients with multiple sclerosis: a combined 31P-MR-spectroscopy and MRI study.
OBJECTIVE: Involvement of the autonomic system in multiple sclerosis (MS) may concur with dysfunction of the cardiovascular system. The introduction of potentially cardiotoxic immunosuppressive drugs like Mitoxantrone into the treatment of MS warrants proper assessment of preexisting heart disease. However, systematic analyses of functional and metabolic derangements in MS are missing. Using quantitative 31P-MR-spectroscopy (MRS) and MR-imaging (MRI) metabolic and functional parameters were analyzed in patients with MS in comparison to healthy volunteers. SUBJECTS/METHODS: 14/15 patients with MS could be included in the study, as the MRS examination of one patient had to be excluded from analysis due to movement during the examination. Using chemical shift imaging (CSI) and AMARES, phosphocreatine (PCr) to adenosine triphosphate (ATP) ratios, characterizing myocardial high-energy phosphate metabolism, were determined. Additionally, absolute concentrations of PCr and ATP were calculated by SLOOP (Spatial Localization with Optimal Pointspread Function). Analysis of functional changes was performed by Cine-MRI. 14 healthy volunteers matched for age and gender served as control. RESULTS: A significant decrease of absolute PCr concentration was observed in patients with MS compared to matched volunteers (p < 0.05), whereas ATP concentrations showed no significant changes (p = 0.27). Metabolite ratios calculated by SLOOP or AMARES showed a tendency to be reduced in patients, however, did not reach significance (p = 0.08, SLOOP; p = 0.47, AMARES). Using volunteers' mean values +/- 2 x SD as cut off value revealed PCr changes in 5 of 14 patients, whereas only 2 also had pathologic PCr/ATP ratios. Functional analysis by MRI depicted depressed left ventricular ejection fraction in 4 patients. CONCLUSIONS: The reduction in cardiac high-energy phosphates in some patients with MS points to a subclinical involvement of the heart. This may be important for treatment with potentially cardiotoxic drugs. Longitudinal studies are need to understand the clinical relevance of our findings.
Adenosine Triphosphate↗
[Interobserver variability in CT of oro- and hypopharyngeal carcinomas].
PURPOSE: To evaluate the inter- and intraobserver reproducibilities of computed tomography (CT) in patients with oro- and hypopharyngeal carcinomas. METHODS: Two independent readers interpreted the CT images of 41 patients with hypopharyngeal carcinomas, 45 patients with oropharyngeal carcinomas, and 23 patients without a tumor. All relevant subregional anatomic structures were evaluated for the presence of tumor infiltration. Statistical analysis was done by using Cohen's kappa and the Wilcoxon test; subregional prevalences, sensitivities, and specificities were also determined. RESULTS: Mostly, especially for clinically relevant subregions, moderate and substantial inter- and intraobserver reproducibilities were determined (range of the determined kappa values: 0.25-1.00). The kappa values of the intraobserver reproducibilities of both readers were not significantly different (P = 0.20). The kappa values of the intraobserver reproducibilities were in almost all the cases higher than the respective kappa values of the interobserver reproducibility. CONCLUSION: CT of oro- and hypopharyngeal carcinomas can be interpreted with clinically acceptable variability. A higher agreement can be achieved if repeated interpretation is done by a single person.
Adult↗
[31P-MR spectroscopy of all regions of the human heart at 1.5 T with acquisition-weighted chemical shift imaging].
AIM: Aim of this study was to show whether or not acquisition-weighted chemical shift imaging (AW-CSI) allows the determination of PCr and ATP in the lateral and posterior wall of the human heart at 1.5 T. METHODS: 12 healthy volunteers were examined using a conventional chemical shift imaging (CSI) and an AW-CSI. The sequences differed only in the number of repetitions for each point in k space. A hanning function was used as filter function leading to 7 repetitions in the center of the k space and 0 in the corners. Thus, AW-CSI had the same resolution as the CSI sequence. The results for both sequences were analyzed using identically positioned voxels in the septal, anterior, lateral and posterior wall. RESULTS: The determined averaged AW-CSI signal to noise ratios were higher for PCr by a factor of 1.3 and for ATP by 1.4 than those of CSI. The PCr/ATP ratios were higher by a factor of 1.2 - 1.3 and showed a smaller standard deviation in all locations for AW-CSI. The mean PCr/ATP ratios determined by AW-CSI of septal, lateral and posterior wall were almost identical (1.72 - 1.76), while it was higher in the anterior wall (1.9). CONCLUSIONS: The reduced contamination in AW-CSI improves the signal to noise ratio and the determination of the PCr/ATP ratio in cardiac (31)P spectroscopy compared to CSI with the same resolution. The results in volunteers indicate that AW-CSI renders (31)P spectroscopy of the lateral and posterior wall of the human heart feasible for patient studies at 1.5 T.
Adenosine Triphosphate↗
The temporomandibular joint and the disc-condyle relationship after functional orthopaedic treatment: a magnetic resonance imaging study.
Causative correction of Class II skeletal malocclusions may be achieved through bite jumping by various means. Numerous animal experiments have yielded evidence of remodelled temporomandibular structures after mandibular protrusion. However, the mode and extent of structural and/or topographic changes of the disc-condyle relationship after functional orthopaedic treatment is still unresolved. A problem exists in defining the physiological position of the condyles and disc-condyle relationship, which is tentatively determined by various methods particularly in magnetic resonance tomographic studies. Despite the high resolution provided, the results have to be interpreted with caution, as osseous resorption and apposition cannot be assessed by visual evidence. This investigation examined the impact on the temporomandibular joints (TMJ), i.e. the condylar shape and position, and the disc-condyle relationship, of the bionator plus extra-oral traction in combination with vertical elastics. The underlying reactions were studied by means of magnetic resonance images (MRI) obtained from n = 15 successfully treated patients (mean age 11.6 years).
Activator Appliances↗
Enhancement of cerebral diseases: how much contrast agent is enough? Comparison of 0.1, 0.2, and 0.3 mmol/kg gadoteridol at 0.2 T with 0.1 mmol/kg gadoteridol at 1.5 T.
RATIONALE AND OBJECTIVES: To determine the clinical dose of gadoteridol (ProHance, Bracco-Byk Gulden) to use for the assessment of blood-brain barrier breakdown on low-field magnetic resonance (MR) scanners that corresponds to a standard dose of gadoteridol on high-field MR scanners. METHODS: This prospective study was carried out at four centers. A total of 138 patients with suspected or known brain diseases underwent a routine head scan comprising precontrast T2-weighted turbo spin-echo and T1-weighted spin-echo sequences on a 1.5-T MR scanner. After administration of a standard dose of 0.1 mmol/kg gadoteridol, the T1-weighted scan was repeated after a delay of 15 to 20 minutes. For continuing the examination on a 0.2-T MR scanner (Magnetom OPEN, Siemens), a standard-dose T1 spin-echo sequence was started within 30 to 50 minutes of the first injection. Then two additional T1-weighted low-field sequences were each started 5 minutes after two additional doses of 0.1 mmol/kg gadoteridol. Eighty patients with enhancing lesions underwent an intraindividual comparison. Evaluation of the overall numbers of lesions detected and of lesion size and character was performed on-site as well as off-site by two independent readers. RESULTS: The single-dose, low-field sequence detected significantly fewer enhancing lesions (80/95 lesions; P < 0.05), particularly metastases and infarctions, than did the standard-dose, high-field sequence. No statistically relevant differences (reader 1: P = 1; reader 2: P = 0.8) were found between the double- and triple-dose, low-field sequences and the standard-dose, high-field sequence. Primary brain tumors were detected by all postcontrast sequences irrespective of the dose. CONCLUSIONS: At low field, the clinically equivalent dose to 0.1 mmol/kg gadoteridol at high field is 0.2 mmol/kg. A dose of 0.1 mmol/kg gadoteridol is less effective and cannot be recommended for use on extremely low-field scanners.
Adult↗
1H spectroscopy in patients with amyotrophic lateral sclerosis.
BACKGROUND AND PURPOSE: The authors investigate changes in brain metabolites among patients with amyotrophic lateral sclerosis (ALS). Twelve patients diagnosed with definite ALS (and 2 subgroups with either pronounced upper motoneuron signs or less obvious, probable upper motoneuron involvement) and 10 controls were examined. 1H studies were performed on a 1.5-T Siemens Magnetom Vision with single voxel (SV). A voxel (TR = 1500 ms, TE = 270 ms, 512 acquisitions, VOI = 8 cm3) was placed bilaterally in the precentral gyrus. In addition, chemical shift imaging (CSI) (VOI = 1 x 1 x 1.5 cm, TR = 1500 ms, TE = 135 ms) was performed. Ratios of peak integrals (N-acetyl-aspartate/choline, N-acetyl-aspartate/creatine, and creatine/choline) were determined. A Mann-Whitney U Test and a Wilcoxon Matched Pairs Test were applied. METHODS: The statistical analysis failed to demonstrate any significant differences between the ALS patients and the controls with respect to ratio measures. Using CSI, it was found that patients with clinically pronounced upper motoneuron signs had significantly lower (P = .037) N-acetyl-aspartate/choline ratios in the more affected hemisphere. CONCLUSIONS: The authors conclude that CSI is more effective at detecting lower N-acetyl-aspartate/choline levels among ALS patients than is SV.
Adult↗
Assessment of myocardial infarction in humans with (23)Na MR imaging: comparison with cine MR imaging and delayed contrast enhancement.
PURPOSE: To demonstrate the feasibility of sodium 23 ((23)Na) magnetic resonance (MR) imaging for assessment of subacute and chronic myocardial infarction and compare with cine, late enhancement, and T2-weighted imaging. MATERIALS AND METHODS: Thirty patients underwent MR imaging 8 days +/- 4 (subacute, n = 15) or more than 6 months (chronic, n = 15) after myocardial infarction by using a (23)Na surface coil with a double angulated electrocardiogram-triggered three-dimensional gradient-echo sequence at 1.5 T. In addition, cine, inversion-recovery gradient-echo, and, in the subacute group, T2-weighted images (n = 9) were obtained. Myocardial infarction mass was depicted as elevated signal intensity or wall motion abnormalities and expressed as a percentage of total left ventricular mass for all modalities. Correlations were tested with correlation coefficients. RESULTS: All patients after subacute infarction and 12 of 15 patients with chronic infarction had an area of elevated (23)Na signal intensity that significantly correlated with wall motion abnormalities (subacute; r = 0.96, P <.001, and chronic; r = 0.9, P <.001); three patients had no wall motion abnormalities or elevated (23)Na signal intensity. Only 10 patients in the subacute and nine in the chronic group revealed late enhancement; significant correlation with (23)Na MR imaging occurred only in subacute group (r = 0.68, P <.05). Myocardial edema in subacute infarction correlated (r = 0.71, P <.05) with areas of elevated (23)Na signal intensity but was extensively larger. CONCLUSION: (23)Na MR imaging demonstrates dysfunctional myocardium caused by subacute and chronic myocardial infarction.
Adult↗
MR angiography of the hand arteries.
The aim of this study was to optimize different magnetic resonance angiography (MRA) techniques and to evaluate MRA of the hand arteries compared to intraarterial digital subtraction angiography (IA-DSA). The MRA examinations were performed on a 1.5-T system equipped with a flexible surface coil. The protocol contained time-of-flight (TOF), rephased/dephased (Re/De), and contrast enhanced (CE) techniques. Maximum intensity projection (MIP) was used for postprocessing. The IA-DSA procedure was performed as pharmaco-angiography (after intraarterial injection of a vasodilatator) via a transbrachial approach. Nine patients suffering from peripheral vascular disease were examined with IA-DSA, TOF-MRA, and Re/De-MRA; six patients were examined with CE-MRA and IA-DSA. Best overall image quality was attained with IA-DSA, followed by TOF-MRA, Re/De-MRA, and CE-MRA. Selective arterial visualization of digital arteries was possible with IA-DSA and TOF-MRA. Rephased/dephased MRA showed venous overlay. Contrast-enhanced MRA was limited by inconstant quality of bolus timing. Appropriate arterial bolus timing was achieved in four of six patients; one examination showed venous overlay, one examination incomplete arterial enhancement. Time-of-flight MRA detected 96% of the digital artery segments that were identified with IA-DSA and revealed 34 segments that were failed on IA-DSA. Rephased/dephased MRA and CE-MRA were inferior to IA-DSA and TOF-MRA regarding detection of digital arteries. Magnetic resonance angiography with optimized protocols is a noninvasive procedure to visualize hand arteries in patients with ischemic disease. With TOF-MRA it is possible to detect angiographically occluded arterial segments of digital arteries.
Adolescent↗
Changes in left and right ventricular cardiac function after valve replacement for aortic stenosis determined by cine MR imaging.
The purpose of this study was to determine the changes in function of both the left and the right ventricles (LV, RV) before and after aortic valve replacement (AVR), compared with age-matched healthy volunteers using magnetic resonance (MR) imaging. Fourteen patients with aortic stenosis underwent MR imaging (1.5 T) before and 3 (n = 14) and 12 (n = 9) months after surgical valve replacement. An electrocardiographically triggered two-dimensional cine fast low-angle shot sequence was used for the evaluation of absolute values and indices related to 1 m(2) body surface area for function, mass, and LV wall thickening. Fourteen age-matched healthy volunteers served as controls. Before surgery, all patients showed significant abnormalities of LV mass and function, whereas RV mass and function were not different from those of volunteers and remained mostly unchanged. After surgery, normalization of LV ejection fraction, absolute mass, and end-systolic wall thickness was observed, whereas the LV mass index failed to normalize, and LV volumes remained elevated. Aortic stenosis combined with a significant, but not severe reduction in LV function only affects the LV, whereas the RV remains unaffected at this stage of disease. AVR leads to improved LV function and reduced hypertrophy, but without normalization of LV volumes or the LV mass index within 1 year.
Aged↗
Deep venous thrombosis and consecutive pulmonary embolism as the first sign of an ovarian cancer: MR angiography using an intravascular contrast agent (CLARISCAN).
We describe a case of progressive deep venous thrombosis and chest pain studied by contrast-enhanced magnetic resonance (MR) angiography with the new intravascular contrast medium CLARISCAN (NC100150 Injection). Combined MR venography and angiography demonstrated pelvic vein thrombosis and consecutive pulmonary embolism caused by a large abdominal tumor, diagnosed as an ovarian cancer after surgery. The potential role of an intravascular contrast medium for studying the vascular system in multiple regions of the body within a single examination without the need for bolus timing is discussed. J. Magn. Reson. Imaging 2000;12:497-500.
Clinical Trials, Phase II as Topic↗
[Evaluating signal intensity of movement-impaired myocardial segments in MR delayed images after administration of Gd-DTPA. Correlation of regional increase in contraction after revascularization].
PURPOSE: The aim of the study was to correlate delayed contrast enhancement of dysfunctional regions of the myocardium after injection of Gd-DTPA with the improvement of regional contractility 3 months after revascularization. MATERIAL AND METHODS: Eleven patients with coronary artery disease and wall motion abnormalities underwent MR imaging before and 3 months after revascularization therapy (PTCA or CABG). Short-axis images were acquired using a cine gradient echo sequence. After revascularization, a representative slice was analyzed 14 +/- 1 min after injection of 0.1 mmol/kg Gd-DTPA using a T1-weighted turbo fast low-angle shot sequence. Improved systolic wall thickening 3 months after revascularization served as criterion of viability and was correlated with delayed contrast enhancement patterns. RESULTS: After revascularization, 6 patients showed complete recovery of the dysfunctional area, 1 patient partial recovery, and 4 patients remained unchanged. All 4 patients with persisting wall motion abnormalities, 1/6 patients with recovery and the patient with partial recovery revealed a delayed enhancement. CONCLUSIONS: Three months after revascularization, delayed enhancement of dysfunctional myocardium is evident in patients without regional wall motion improvement, while the lack of delayed enhancement correlates with improvement of regional contractility.
Adult↗