Biomedical subjects

Gabriele A Krombach

Publications and source records attributed to Gabriele A Krombach.

At least 19 recordsLinked to original sources

PubMed2007

Characterization of myocardial viability using MR and CT imaging.

Cardiovascular magnetic resonance (MR) imaging is of proven clinical value for the noninvasive characterization of myocardial viability. Computed tomography (CT) is also being exploited for this indication. Examples of each of these imaging strategies for the assessment of myocardial viability will be provided in this review. Key MRI concepts and practical considerations such as customized MR imaging techniques and tailored imaging protocols dedicated to viability assessment are outlined with the primary focus on recent developments. Clinical applications of MR-based viability assessment are reviewed, ranging from rapid functional cine imaging to tissue characterization using T2-weighted imaging and T1-weighted late-contrast-enhanced imaging. Next, the merits and limitations of state-of-the-art CT imaging are surveyed, and their implications for viability assessment are considered. The final emphasis is on current trends and future directions in noninvasive viability assessment using MRI and CT.

Contrast Media↗

PubMed2006

Assessment of reversible myocardial dysfunction in chronic ischaemic heart disease: comparison of contrast-enhanced cardiovascular magnetic resonance and a combined positron emission tomography-single photon emission computed tomography imaging protocol.

AIMS: The aim of the study was to compare, in patients with chronic ischaemic cardiomyopathy, contrast-enhanced cardiovascular magnetic resonance (ce-CMR) imaging and a combined (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) and (99m)Tc-sestamibi single-photon emission computed tomography (SPECT) protocols for the prediction of functional recovery after revascularization, as assessed by cine CMR. METHODS AND RESULTS: Twenty-nine patients with ischaemic cardiomyopathy (ejection fraction 32 +/- 10%) were investigated with ce-CMR and PET/SPECT. For the assessment of global and regional functions, cine CMR was performed at baseline and at 6 months follow-up. For ce-CMR, the segmental extent of hyperenhancement (SEH) was quantitated, and for PET/SPECT, different viability categories were defined according to a validated quantitative protocol. Functional improvement was related to the SEH by ce-CMR, as well as to the viability categories by PET/SPECT. Sensitivity and specificity for the prediction of functional recovery at follow-up was 97 and 68% for ce-CMR and 87 and 76% for PET/SPECT. The positive predictive value was identical for both techniques (73%). However, ce-CMR achieved a higher negative predictive value (93 vs. 77%, respectively), indicating that ce-CMR may be superior to PET/SPECT for the identification of segments unlikely to recover function after revascularization. Both methods had a similar yield in the prediction of global functional improvement. CONCLUSION: ce-CMR is comparable with a PET/SPECT imaging protocol for the prediction of regional and global functional improvement after revascularization. However, ce-CMR may be superior to nuclear imaging for the identification of segments that are unlikely to recover function at follow-up.

Chronic Disease↗

PubMed2005

Dehiscence of the superior and/or posterior semicircular canal: delineation on T2-weighted axial three-dimensional turbo spin-echo images, maximum intensity projections and volume-rendered images.

The purpose of this study was to compare the ability of T2-weighted three-dimensional turbo spin-echo (TSE) images, maximum intensity projections and three-dimensional volume-rendered images for delineation of semicircular canal dehiscence. In 26 patients with dehiscence of the superior and/or posterior semicircular canal and 26 control patients, TSE images were obtained with two different resolutions and maximum intensity projection (MIP) and 3D volume-rendered images reconstructed. All images were evaluated by two radiologists in consensus regarding the visualization of anatomical structures and dehiscence of the semicircular canals. Computed tomography was used to confirm or exclude dehiscence. Dehiscence of the semicircular canals was delineated on axial MR images and on 3D volume-rendered images, but not on MIP images. The number of false positive cases was reduced from 3 to 0 with an increase in matrix, rendering results similar to those obtained with CT. Dehiscence of the semicircular canals can be assessed on high resolution MR images. Volume-rendered 3D images allow for immediate perception of the location of defects in semicircular canal dehiscence. These images may facilitate understanding of the extent and location of the defects.

Adolescent↗

PubMed2005

New method of dynamic color doppler signal quantification in metastatic lymph nodes compared to direct polarographic measurements of tissue oxygenation.

Tumor growth depends on sufficient blood and oxygen supply. Hypoxia stimulates neovascularization and is a known cause for radio- and chemoresistance. The objective of this study was to investigate the use of a novel ultrasound technique for the dynamic assessment of vascularization and oxygenation in metastatic lymph nodes. Twenty-four patients (age 44-78 years) with cervical lymph node metastases of squamous cell head and neck cancer were investigated by color duplex sonography and 17 (age 46-78 years) were investigated additionally with polarography. Sonography was performed after contrast enhancer infusion under defined conditions. Intranodal perfusion data (color hue, colored area) were measured automatically by a novel software technique. This allows an evaluation of blood flow dynamics by calculating perfusion intensity--velocity, perfused area, as well as the novel parameters tissue resistance index (TRI) and tissue pulsatility index (TPI)--for each point of a complete heart cycle. Tumor tissue pO(2) was measured by means of polarographic needle electrodes placed intranodally. The sonographic and polarographic data were correlated using Pearson's test. Sonography demonstrated a statistically significant inverse correlation between hypoxia and perfusion and significant TPI and TRI changes with different N-stages. The percentage of nodal fraction with less than 10 mmHg oxygen saturation was significantly inversely correlated with lymph node perfusion (r = -0.551; p = 0.021). Nodes with a perfusion of less than 0.05 cm/sec flow velocity showed significantly larger hypoxic areas (p = 0.006). Significant differences of TPI and TRI existed between nodes in stage N(1) and N(2)/N(3) (p = 0.028 and 0.048, respectively). This new method of dynamic signal quantification allows a noninvasive and quantitative assessment of tumor and metastatic lymph node perfusion by means of commonly available ultrasound equipment.

Adult↗

PubMed2005

Computed tomography of the inner ear: size of anatomical structures in the normal temporal bone and in the temporal bone of patients with Menière's disease.

The purpose of the study was to obtain reference values for the sizes of anatomical structures of the inner ear on computed tomography (CT) images and to compare these values with those obtained from patients with Menière's disease. CT images of the temporal bone of 67 patients without inner ear pathology and 53 patients with Menière's disease have been evaluated. CT was performed in the sequential mode (1-mm slice thickness, 120 kV, 125 mA). Anatomical structures, such as the length and the width of the cochlea and of the vestibule, the height of the basal turn, the length and the width of the cochlear, the vestibular and the singular aqueduct and the internal auditory meatus and the diameter of the semicircular canals, were measured, using a dedicated postprocessing workstation. Reference values from the control group could be obtained. In the patients with Menière's disease, the length and the width of the vestibular aqueduct were smaller, compared with the values from the control group. The values obtained from the control group can serve as reference values for adult patients. The different sizes of anatomical structures of the control group and of patients suffering from Menière's disease suggest that functional impairment might be related to subtle morphological changes.

Case-Control Studies↗

PubMed2005

A feasibility study of contrast enhancement of acute myocardial infarction in multislice computed tomography: comparison with magnetic resonance imaging and gross morphology in pigs.

INTRODUCTION: Late enhancement magnetic resonance imaging (MRI) of myocardial infarction (MI) is clinically established. There are no reports on MI assessment using state-of-the-art multislice CT technology. For this reason, animal experiments were conducted to examine the applicability of contrast-enhanced ECG-gated multislice computed tomography (MSCT) for the detection of acute MI. The results were correlated with MRI and postmortem tissue staining. MATERIAL AND METHODS: Acute MI was induced in 14 pigs by balloon occlusion of the LAD. In 8 animals, the LAD was reperfused after 45 minutes. In 6 animals, the LAD was permanently blocked. MR imaging was performed 15 minutes after the administration of 0.2 mmol Gd-DTPA/kg/bodyweight. Subsequently, 16-slice MSCT was performed at various timepoints after injecting 120 mL of iodinated contrast medium. 2,3,5-Triphenyltetrazolin-chloride (TTC) staining was acquired for all hearts investigated. Correlation analysis was applied to compare the area of MI derived from MRI, MSCT, and TTC. The reperfused infarcts were compared with the nonreperfused infarcts using an unpaired t test. RESULTS: : Mean infarct area as measured by TTC staining was 18.3% +/- 7.8% of the left ventricular area. Good correlation of the spatial extent of the infarcted area was found for TTC and MRI as well as for TTC and MSCT data obtained 5 minutes postcontrast injection. MSCT imaging demonstrated a significant difference in density (P < 0.001) between nonreperfused (47.0 +/- 6.6 HU) and reperfused (116.4 +/- 19.8 HU) infarction. CONCLUSION: In our pilot study, contrast-enhanced MSCT was feasible to assess myocardial viability in pigs. MSCT also affords differentiation of nonreperfused and reperfused acute MI. MI sizes derived from MSCT imaging correlate well to those obtained with MRI and TTC.

Animals↗

PubMed2005

MR-guided percutaneous intramyocardial injection with an MR-compatible catheter: feasibility and changes in T1 values after injection of extracellular contrast medium in pigs.

PURPOSE: To assess the feasibility of percutaneous magnetic resonance (MR)-guided intramyocardial injection of gadodiamide by using real-time imaging and to quantify T1 values and the size of the enhanced region for different concentrations of contrast agent for 30 minutes after injection. MATERIALS AND METHODS: Animal care committee approval was obtained. A catheter with a needle tip was advanced into the left ventricle in seven pigs by using real-time imaging with radial steady-state free precession. After intramyocardial injection of 2 mL of solution at concentrations of 0.05 or 0.10 mmol/mL gadodiamide, local changes in T1 values and size of the contrast material-enhanced region were sequentially measured at 3, 15, and 30 minutes after injection by using the Look-Locker sequence. Two-tailed paired Student t tests were used for statistical analysis. RESULTS: Catheter guidance and visualization of contrast agent distribution were feasible in all animals. Regional changes in T1 values were significantly different for different contrast agent concentrations (for 0.05 mmol/mL, 456 msec +/- 5 [+/- standard error of the mean]; for 0.10 mmol/mL, 228 msec +/- 4; P < .001) measured 3 minutes after injection. T1 values increased significantly (P < .05) to 720 msec +/- 7 for 0.05 mmol/mL gadodiamide and 445 msec +/- 6 for 0.10 mmol/mL gadodiamide 30 minutes after injection but remained significantly lower than those of remote myocardium (879 msec +/- 8). The size of the contrast-enhanced region increased from 13 mm(2) +/- 2 at 3 minutes to 30 mm(2) +/- 3 at 30 minutes (P < .05). CONCLUSION: Catheter MR-guided percutaneous intramyocardial injection is feasible; after intramyocardial injection of gadodiamide at concentrations of 0.05 and 0.10 mmol/mL, T1 values decreased over the observation time.

Animals↗

PubMed2005

Gadomer-enhanced MR imaging in the detection of microvascular obstruction: alleviation with nicorandil therapy.

PURPOSE: To evaluate Gadomer-enhanced magnetic resonance (MR) imaging in the quantification of small microvascular obstruction regions and determine if nicroandil alleviates the formation of microvascular obstruction. MATERIALS AND METHODS: Approval of the institutional committee on animal research was obtained, and this study complied with guidelines for care and use of animals. Rats underwent coronary artery occlusion and reperfusion. After 24 hours, Gadomer-enhanced T1-weighted spin-echo MR imaging was used to define microvascular obstruction in animals in control and nicorandil groups. Sequential MR images obtained at two midventricular levels were acquired to measure microvascular obstruction and ischemically injured regions and monitor diffusive and/or convective transport of Gadomer in microvascular obstruction regions. Two investigators working in consensus and using threshold signal intensity measured differentially enhanced regions. Left-ventricular (LV) end-systolic and end-diastolic MR images obtained at the same two midventricular levels were used to measure regional wall thickening and systolic reduction in LV relative volumes. Agreement and correlation between MR imaging and postmortem data were determined with Bland-Altman and linear regression analyses. Animals were sacrificed 3 minutes after intravenous injection of blue dye. RESULTS: On Gadomer-enhanced MR images, two differentially enhanced regions were observed in ischemically injured myocardium, namely, the hypoenhanced region and the surrounding hyperenhanced region. Hypoenhanced regions at MR imaging and unstained regions at blue dye administration were identical 3 minutes after administration (17% +/- 1 and 17% +/- 2; P = .6; r = 0.98). In the control group, Gadomer provided a prolonged imaging window (eg, 6 minutes) for accurately quantifying small microvascular obstruction regions. Microvascular obstruction was observed in all animals in the control group and 27% of animals in the nicorandil group. Microvascular obstruction regions were smaller in the nicorandil group (eg, 3% +/- 1) than in the control group (eg, 17% +/- 2) (P < .001). Hyper- and hypoenhanced regions were also smaller (eg, 20% +/- 2) in rats in the nicorandil group than in those in the control group (37% +/- 4, P < .001). Improvement in LV function in the nicorandil group is likely related to alleviation and reduction in infarct size. CONCLUSION: Gadomer-enhanced MR imaging can be used to quantify small microvascular obstruction regions 24 hours after reperfusion. Intravenous therapy with nicorandil reduces formation of microvascular obstruction regions.

Animals↗

PubMed2005

Minimally invasive close-chest method for creating reperfused or occlusive myocardial infarction in swine.

RATIONALE AND OBJECTIVES: We sought to evaluate a closed-chest model for reperfused and occlusive myocardial infarction (MI) in pigs and to report experiences and pitfalls. MATERIAL AND METHODS: In 44 pigs, a balloon catheter was advanced into the left descending coronary artery (LAD) under fluoroscopic guidance. The balloon was inflated and occlusion of the vessel angiographically confirmed while ECG was continuously monitored. In case of ventricular fibrillation, direct current defibrillation was performed. In 6 animals, the balloon was left inflated during the following experiments, to obtain occlusive MI. In all other cases, the balloon was deflated after 45 minutes. After the experiments were finished, the hearts were stained with 2,3,5-triphenyltetrazolium chloride for assessment of infarct size. RESULTS: MI was successfully induced in 34 animals (28 reperfused and 6 occlusive). Mean size of MI was 15.8 +/- 5.1% of left ventricular surface area for reperfused and 21.5 +/- 8.7% for occlusive infarcts. In one pig, 2,3,5-triphenyltetrazolium chloride did not confirm infarction. In 26 pigs, ventricular fibrillation occurred. Defibrillation was successful in 17 pigs. Failure rate because of ventricular fibrillation decreased from 42% (6) in the first 14 to 10% (3) in the next 30 animals. One animal died due to technical failure of the ventilator. After initial experiences, we used balloon catheters with a diameter of 2-3 mm, instead of 4 mm. The smaller balloon sizes were used so as to decrease the incidence of fibrillation. CONCLUSIONS: The described technique of LAD occlusion presents a less invasive alternative to open chest models. The major pitfall, causing fatal arrhythmia in our series, was over-dilatation of the LAD with the balloon catheter.

Animals↗

PubMed2004

Cine MR imaging of heart valve dysfunction with segmented true fast imaging with steady state free precession.

PURPOSE: To evaluate the value of cine true fast imaging with steady-state free precession (SSFP) for semiquantitative assessment of valvular dysfunction in the heart and to compare the results to that obtained with a standard breath-hold segmented gradient-recalled echo-planar imaging sequence (GE-EPI). MATERIALS AND METHODS: Twenty-three patients with known valvular dysfunction (main component: 16 with aortic valve stenosis, nine with aortic valve insufficiency, three with mitral stenosis, two with mitral regurgitation, two with tricuspidal regurgitation, and one with pulmonary stenosis) and 23 control subjects with normal valvular function underwent MR imaging on a 1.5-T system (ACS-NT, Philips, Best, The Netherlands). Cine SSFP and GE-EPI images were acquired in identical long-axis views. Images were evaluated for the presence and extent of the signal void arising from the valves and for image quality consensus by two experienced radiologists. Results were compared to those obtained by cardiac catheterization (in 16 patients) or color Doppler (in the remaining seven patients). RESULTS: On SSPF images, the complex flow pattern in valvular regurgitant or stenotic lesions caused signal void within the bright blood pool of the atria or ventricles, similar to GE-EPI, in all patients. Valvular dysfunction was delineated using SSFP with the same high sensitivity (100%) as using the GE-EPI sequence. Results correlated to those obtained by cardiac catheterization or color Doppler ultrasonography (P < 0.001, r = 0.97). However, the jet phenomenon was slightly more pronounced in five patients on GE-EPI. There was no significant signal void in the 23 control subjects with both sequences. In all 46 subjects, the image quality of SSFP images was rated higher (P < 0.05; 2.6 +/- 0.1; using a scale ranging from 0-3) compared to GE-EPI (1.7 +/- 0.1). CONCLUSION: The results of this study suggest that valvular dysfunction can be semiquantitatively assessed using SSFP cine MR imaging.

Adult↗

PubMed2004

MR-guided radiofrequency ablation of hepatic malignancies at 1.5 T: initial results.

PURPOSE: To assess the feasibility of magnetic resonance (MR)-guided radiofrequency ablation (RFA) of hepatic malignancies using a high-field MR scanner. MATERIALS AND METHODS: A total of 10 patients with 14 primary (N = 1) or secondary (N = 13) hepatic malignancies underwent MR-guided RFA using a closed-bore 1.5 T MR scanner. Lesion diameters ranged from 2.0 cm to 4.7 cm. RFA was performed using a 200-W generator in combination with a 3.5-cm LeVeen electrode applying a standardized energy protocol. RESULTS: RFA was technically feasible in all patients. Necrosis diameter ranged from 2.5 cm to 6.8 cm. The mean follow-up period is 12.2 (1-18) months. In nine out of 10 patients, local tumor control was achieved. For this purpose, a second CT-guided RFA was required in two patients. In four patients, multifocal hepatic tumor progression occurred, with the treated lesion remaining tumor-free in three of these patients. Two patients showed extrahepatic tumor progression. Four patients remained tumor-free. No major complications occurred. CONCLUSION: MR-guided RFA of hepatic malignancies in a closed-bore high-field MR scanner is technically feasible and safe. It can be advantageous in locations considered unfavorable for CT-guided puncture or in patients in which iodinated contrast material is contraindicated.

Aged↗

PubMed2004

T2-weighted turbo spin-echo images, maximum-intensity projections, and three-dimensional volume-rendering for delineation of pathologies and anatomic details of the inner ear.

PURPOSE: The aim of the current study was to compare 3-dimensional T2-weighted turbo spin-echo (TSE) axial slices, maximum-intensity projections (MIPs), and volume-rendered images with respect to the delineation of pathologic findings and anatomic structures of the inner ear. Each of the compared image types was available at 2 different resolutions. MATERIALS AND METHODS: In 64 patients, 3-dimensional T2-TSE images were acquired with a matrix of 128 x 100 and 230 x 230 (field-of-view 90 x 90 mm). Direct axial images, MIPs, and volume-rendered images from the 2 datasets were evaluated in terms of the delineation of pathologic findings and anatomic structures. Analysis was performed by 2 radiologists in consensus. RESULTS: Though axial images acquired with a matrix of 230 x 230 showed more anatomic details than images acquired with a matrix of 128 x 100, pathologic findings (33 in total) were assessable with the same confidence on images of either resolution. Pathologies completely surrounded by fluid were best assessed on axial slices. The delineation of pathologies not embedded in a fluid was almost equally good in axial slices, MIPs, or 3-dimensional volume-rendered images. CONCLUSION: Reading the axial images cannot be replaced by viewing postprocessed reconstructions for initial diagnosis, because only some of the pathologies can be delineated on MIPs and volume reconstructions. However, reconstructions can be valuable for assessing the extent of pathologies and their spatial relation to the anatomic structures.

Adolescent↗

PubMed2004

Is postcontrast trueFISP imaging advantageous?

RATIONALE AND OBJECTIVES: Contrast of trueFISP images depends mainly on the T2/T1 ratio. Consequently, there is a potential gain in signal intensity after administration of paramagnetic contrast medium despite the strong T2 weighting. The purpose of this study was to analyze signal intensities of abdominal organs after applying contrast medium and to determine whether this yields an improved contrast for pathologies compared with precontrast trueFISP. MATERIALS AND METHODS: Fifty patients underwent an abdominal examination, including the trueFISP sequence before and after the administration of contrast medium. All images were obtained with a 1.5 T system. The mean signal-to-noise ratio before and after contrast medium was assessed for abdominal organs, vessels, muscle, and fat. The contrast-to-noise ratio (CNR) of pathologic lesions was calculated. RESULTS: The trueFISP sequence yielded a higher signal-to-noise ratio after application of contrast medium for all organs except for fat and the aorta. CNR of solid lesions (angiomyolipoma, liver adenoma, liver hemangioma, hepatocellular carcinoma) increased whereas contrast of cysts decreased. CONCLUSIONS: TrueFISP imaging after application of contrast medium led to better CNR for many solid lesions while cysts showed a diminished contrast. We advise trueFISP imaging sequences before and after contrast medium application.

Abdomen↗

PubMed2004

Contrast-enhanced MR delineation of stunned myocardium with administration of MnCl(2) in rats.

PURPOSE: To determine whether stunned myocardium can be delineated at magnetic resonance (MR) imaging with differential cellular uptake of manganese ions. MATERIALS AND METHODS: Twenty-one adult Sprague-Dawley rats underwent either (a) a sequence of three episodes of 10 minutes of coronary artery occlusion and 12 minutes of reflow (group 1, n = 9); (b) a single episode of 10 minutes of occlusion followed by reflow (group 2, n = 6), designed to produce different degrees of myocardial stunning; or (c) a single episode of 2 minutes of occlusion followed by reperfusion (group 3, n = 6), designed to produce no stunning. Ventricular wall thickening was measured on spin-echo (SE) MR images. MnCl2 (0.025 mmol/kg) was intravenously infused for 10 minutes. Highly T1-sensitive inversion-recovery (IR) SE images were obtained to detect subtle regional differences in manganese accumulation. Hearts were stained at sacrifice to define area at risk and to test for myocardial infarction. Significance of differences in mean values was evaluated with repeated-measures analysis of variance. RESULTS: All hearts were free of infarction, as detected with triphenyltetrazolium chloride staining. On IR SE images, the hearts from rats in groups 1 and 2 exhibited clearly delineated regions of diminished manganese uptake in the expected territory of the occluded artery. The circumferential extent of the manganese-defined defect (45.5% +/- 5.6) was similar to that of the area at risk (46.8% +/- 7.5). Systolic wall thickening in the defect was significantly (P <.01) less than in the nonischemic myocardium (2.7% +/- 3.3 vs 31.2% +/- 7.5 and 10.0% +/- 4.8 vs 28.6% +/- 6.5, respectively, for groups 1 and 2). The hearts from rats in group 3 demonstrated no wall thickening deficit or abnormal zone on manganese-enhanced images. CONCLUSION: Stunned myocardium was delineated with MnCl2-enhanced MR imaging as a hypoenhanced zone. This finding suggests that Ca2+ channel activity is diminished in stunned myocardium.

Animals↗

PubMed2004

Transendocardial delivery of extracellular myocardial markers by using combination X-ray/MR fluoroscopic guidance: feasibility study in dogs.

PURPOSE: To demonstrate the feasibility of using a combination of x-ray fluoroscopic and magnetic resonance (MR) fluoroscopic (ie, x-ray/MR fluoroscopy) guidance for left ventricular (LV) catheterization and transendocardial delivery of extracellular tissue markers. MATERIALS AND METHODS: Experiments were performed in six dogs by using an x-ray/MR fluoroscopy system. The arterial guide wire and catheter were advanced into the heart with x-ray fluoroscopic guidance. The dogs were injected with 0.5, 1.0, and 2.0 mL of iohexol. For passive catheter tracking, a steady-state free precession MR imaging sequence was used. A steerable dual-lumen catheter was used to transendocardially inject a mixture of gadodiamide (0.05 mol/L) plus Evans blue dye (3%). An electrocardiographically gated dual-inversion-recovery MR imaging sequence was used to visualize the myocardial delivery of the gadodiamide-blue dye mixture. A high concentration of gadodiamide (0.5 mol/L) was used to demarcate the borders of the area of interest, or "hit the target." Blood pressure, heart rate, and oxygen saturation were measured before and after the intervention. Analysis of variance, Scheffé, and paired Student t tests were used for data analysis. RESULTS: LV catheterization via arterial access was feasible with two-dimensional x-ray fluoroscopic and three-dimensional MR fluoroscopic guidance. Delivery of the gadodiamide-blue dye mixture and the consequences of the procedure were monitored with MR imaging. Gadolinium-enhanced regions were bright on T1-weighted MR images, but they varied in size as a function of injectant volume. The mean sizes of these regions were 1.5% +/- 0.6 of the LV after the 0.5-mL injection of the mixture and 7.0% +/- 0.5 of the LV after the 2.0-mL injection (P <.001, Scheffé test). The corresponding mean sizes of the blue dye-enhanced regions were 2.3% +/- 0.6 and 8.3% +/- 0.4, respectively (P <.001). A high concentration of gadodiamide caused signal intensity loss around the gadolinium-enhanced regions. CONCLUSION: Transendocardial delivery of potential therapeutic solutions is feasible with x-ray/MR fluoroscopic guidance. The injection catheter can be navigated with MR imaging guidance to hit the target.

Animals↗

PubMed2004

Validation of QGS and 4D-MSPECT for quantification of left ventricular volumes and ejection fraction from gated 18F-FDG PET: comparison with cardiac MRI.

UNLABELLED: The aim of this study was to validate Quantitative Gated SPECT (QGS) and 4D-MSPECT for assessing left ventricular end-diastolic and systolic volumes (EDV and ESV, respectively) and left ventricular ejection fraction (LVEF) from gated (18)F-FDG PET. METHODS: Forty-four patients with severe coronary artery disease were examined with gated (18)F-FDG PET (8 gates per cardiac cycle). EDV, ESV, and LVEF were calculated from gated (18)F-FDG PET using QGS and 4D-MSPECT. Within 2 d (median), cardiovascular cine MRI (cMRI) (20 gates per cardiac cycle) was done as a reference. RESULTS: QGS failed to accurately detect myocardial borders in 1 patient; 4D-MSPECT, in 2 patients. For the remaining 42 patients, correlation between the results of gated (18)F-FDG PET and cMRI was high for EDV (R = 0.94 for QGS and 0.94 for 4D-MSPECT), ESV (R = 0.95 for QGS and 0.95 for 4D-MSPECT), and LVEF (R = 0.94 for QGS and 0.90 for 4D-MSPECT). QGS significantly (P < 0.0001) underestimated LVEF, whereas no other parameter differed significantly between gated (18)F-FDG PET and cMRI for either algorithm. CONCLUSION: Despite small systematic differences that, among other aspects, limit interchangeability, agreement between gated (18)F-FDG PET and cMRI is good across a wide range of clinically relevant volumes and LVEF values assessed by QGS and 4D-MSPECT.

Aged↗

PubMed2003

Distribution of intramyocardially injected extracellular MR contrast medium: effects of concentration and volume.

The purpose of this study was to assess the potential of intramyocardially injected Gd-DTPA solution as a marker for distribution of intramyocardially delivered therapeutic solutions. The effects of concentration and volume of the extracellular MR contrast medium Gd-DTPA on signal intensity and spatial extent of enhancement was determined after intramyocardial delivery. In anesthetized pigs (n=11), mixtures of Gd-DTPA (0.15, 0.1 and 0.05 mmol/ml) and Evan's blue tissue dye (3%) were injected into the wall of the left ventricle. In each pig 1 ml of 0.15 mmol/ml, 2 ml of 0.1 ml and 3 ml of 0.05 mmol/ml Gd-DTPA were injected remote from each other. Arterial blood pressure, heart rate and ECG were monitored throughout the procedure. Five minutes after injections were performed, the pigs were killed and the hearts excised. T1-weighted spin-echo MR images were acquired to measure regional signal intensity (SI) and extent of the enhanced regions. The hearts were sliced and mass of blue stained regions was determined and compared with mass of enhanced areas on MRI. Gd-DTPA significantly (p<0.001) increased regional SI compared with remote myocardium in a concentration dependent fashion (109 +/- 4% at 0.05 mmol/ml, 202 +/- 7% at 0.1, and 327 +/- 6% at 0.15) while the mass of enhanced region was 0.6 +/- 0.1 g after injection of 1 ml, 1.4 +/- 0.2 g after 2 ml and 2.3 +/- 0.3 g after 3 ml (p<0.001). Regression and Bland-Altman analysis revealed that there was close correlation and agreement between MRI and histomorphometry (r=0.98, p<0.001). Magnitude and spatial extent of enhancement depend on concentration and volume of injected contrast medium. Intramyocardial injection of extracellular MR contrast media may be useful as a marker for the extent of distribution of intramyocardially delivered therapeutic solutions.

Animals↗

PubMed2003

Diagnosis and treatment of arthrosis of cervical articular facet joints in Scottish Deerhounds: 9 cases (1998-2002).

OBJECTIVE: To determine diagnostic features and efficacy of treatment of arthrosis of the cervical articular facet joints between C2 and C3 in Scottish Deerhounds. DESIGN: Retrospective study. ANIMALS: 9 client-owned dogs. PROCEDURE: Medical records of affected dogs were reviewed. Diagnosis was confirmed by results of clinical examination (signs of severe pain from unilateral or bilateral flexion of the cervical vertebral column), radiography, myelography, and computed tomography. Treatment consisted of fluoroscopy-guided intra-articular injection of corticosteroids and lidocaine. RESULTS: Unilateral or bilateral arthrosis of the cervical facet joints between C2 and C3 was detected in all dogs. In 7 dogs, signs of pain were elicited by flexion of the side of the neck in which affected joints were detected radiographically. Two dogs had signs of pain during right lateral flexion, although bilateral lesions were detected. Five dogs had unilateral lesions, and 4 dogs had bilateral lesions; sclerosis and hypertrophy of the articular process were common. Two dogs had bridging of the articular space. Use of computed tomography confirmed the diagnosis. Myelography did not reveal abnormalities of the spinal cord or canal. After treatment, 8 dogs had rapid marked improvement of clinical signs, and 7 dogs remained free of clinical signs for > 4 months. CONCLUSIONS AND CLINICAL RELEVANCE: Arthrosis of the cervical facet joints in Scottish Deerhounds is a severely painful condition for which conventional radiography is a useful screening test. Intra-articular administration of corticosteroids and anesthetic is efficacious, long-lasting, and minimally invasive.

Adrenal Cortex Hormones↗