[Extrarenal parametrial angiomyolipoma of the ovarian vein with extension into the right atrium].
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Angiomyolipoma↗
Biomedical subjects
S Feuerbach
Publications and source records attributed to S Feuerbach.
In vitro evaluation of stent patency and in-stent stenoses in 10 metallic stents using MR angiography.
In vitro study to investigate the suitability of contrast enhanced magnetic resonance angiography (CEMRA) for determination of stent patency and grading of in-stent stenoses in 10 metallic stents. The Acculink carotid, DynaLink, Easy Wallstent, JostentSelfX XF, Luminexx, Omnilink, sinus-SuperFlex, SMART, Symphony and ZA stent were separately placed in a vascular phantom. Dedicated stenoses inside the stents generated a concentric lumen narrowing of 50%. CEMRA was performed for each stent. Signal loss inside the stents and artificial lumen narrowing were assessed objectively using the evaluation software of the MR imager. Moreover, three blinded observers determined visibility of stent patency and in-stent stenoses subjectively on a 3-point scale and graded in-stent stenoses. Loss of signal intensity within the stent lumen ranged between 90% (Wallstent) and 5% (ZA), artificial lumen narrowing between 56% (Symphony) and 22% (ZA). For the Symphony and Wallstent, visibility of patency and in-stent stenoses was impaired and the observers' grading exaggerated the degree of stenoses (by 23% and 33%, respectively). For the remainder of stents, patency and stenoses were visible and stenoses were graded accurately (less than 10% discrepancy from reference standard). In this in vitro study, eight of 10 stents presented with MRI characteristics which enabled determination of stent patency and accurate grading of clinically relevant in-stent stenoses.
Artifacts↗
Delayed hyperenhancement in magnetic resonance imaging of left ventricular hypertrophy caused by aortic stenosis and hypertrophic cardiomyopathy: visualisation of focal fibrosis.
OBJECTIVE: To compare the extent and distribution of focal fibrosis by gadolinium contrast-enhanced magnetic resonance imaging (MRI; delayed hyperenhancement) in severe left ventricular (LV) hypertrophy in patients with pressure overload caused by aortic stenosis (AS) and with genetically determined hypertrophic cardiomyopathy (HCM). METHODS: 44 patients with symptomatic valvular AS (n = 22) and HCM (n = 22) were studied. Cine images were acquired with fast imaging with steady-state precession (trueFISP) on a 1.5 T scanner (Sonata, Siemens Medical Solutions). Gadolinium contrast-enhanced MRI was performed with a segmented inversion-recovery sequence. The location, extent and enhancement pattern of hyperenhanced myocardium was analysed in a 12-segment model. RESULTS: Mean LV mass was 238.6 (SD 75.3) g in AS and 205.4 (SD 80.5) g in HCM (p = 0.17). Hyperenhancement was observed in 27% of patients with AS and in 73% of patients with HCM (p < 0.01). In AS, hyperenhancement was observed in 60% of patients with a maximum diastolic wall thickness >or= 18 mm, whereas no patient with a maximum diastolic wall thickness < 18 mm had hyperenhancement (p < 0.05). Patients with hyperenhancement had more severe AS than patients without hyperenhancement (aortic valve area 0.80 (0.09) cm(2)v 0.99 (0.3) cm(2), p < 0.05; maximum gradient 98 (22) mm Hg v 74 (24) mm Hg, p < 0.05). In HCM, hyperenhancement was predominant in the anteroseptal regions and patients with hyperenhancement had higher end diastolic (125.4 (36.9) ml v 98.8 (16.9) ml, p < 0.05) and end systolic volumes (38.9 (18.2) ml v 25.2 (1.7) ml, p < 0.05). The volume of hyperenhancement (percentage of total LV myocardium), where present, was lower in AS than in HCM (4.3 (1.9)% v 8.6 (7.4)%, p< 0.05). Hyperenhancement was observed in 4.5 (3.1) and 4.6 (2.7) segments in AS and HCM, respectively (p = 0.93), and the enhancement pattern was mostly patchy with multiple foci. CONCLUSIONS: Focal scarring can be observed in severe LV hypertrophy caused by AS and HCM, and correlates with the severity of LV remodelling. However, focal scarring is significantly less prevalent in adaptive LV hypertrophy caused by AS than in genetically determined HCM.
Aortic Valve Stenosis↗
Crohn's disease of the esophagus: treatment of an esophagobronchial fistula with the novel liquid embolic polymer "onyx".
Esophageal involvement in Crohn's disease is very rare. In only a small subgroup of these patients -- up to date fourteen cases have been described in the literature -- the course of the illness may be complicated by esophageal fistula formation. The therapy for fistulizing esophageal Crohn's disease so far has been disappointing, recurrence and progression are likely, and surgery still is the primary treatment modality for refractory patients. We here present a case of severe Crohn's disease with an esophagobronchial fistula and the successful closure of the fistula tract with the novel liquid polymer sealant "Onyx". This approach offers a new option for the treatment of this rare complication of Crohn's disease and should be considered if surgery is not possible.
Adolescent↗
MRI planimetry for diagnosis and follow-up of valve area in mitral stenosis treated with valvuloplasty.
PURPOSE: We sought to determine whether noninvasive planimetry by magnetic resonance imaging (MRI) is suitably sensitive and reliable for visualizing the mitral valve area (MVA) and for detecting increases in the MVA after percutaneous balloon mitral valvuloplasty (PBMV). MATERIALS AND METHODS: In 8 patients with mitral valve stenosis, planimetry of the MVA was performed before and after PBMV with a 1.5 T MR scanner using a breath-hold balanced gradient echo sequence (True FISP). The data was compared to the echocardiographically determined MVA (ECHO-MVA) as well as to the invasively calculated MVA by the Gorlin formula at catheterization (CATH-MVA). RESULTS: PBMV was associated with an increase of 0.79 +/- 0.30 cm (2) in the MVA (Delta MRI-MVA). The correlation between Delta MRI-MVA and Delta CATH-MVA was 0.92 (p < 0.03) and that between Delta MRI-MVA and Delta ECHO-MVA was 0.90 (p < 0.04). The overall correlation between MRI-MVA and CATH-MVA was 0.95 (p < 0.0001) and that between MRI-MVA and ECHO-MVA was 0.98 (p < 0.0001). MRI-MVA slightly overestimated CATH-MVA by 8.0 % (1.64 +/- 0.45 vs. 1.51 +/- 0.49 cm (2), p < 0.01) and ECHO-MVA by 1.8 % (1.64 +/- 0.45 vs. 1.61 +/- 0.43 cm (2), n. s.). CONCLUSION: Magnetic resonance planimetry of the mitral valve orifice is a sensitive and reliable method for the noninvasive quantification of mitral stenosis and visualization of small relative changes in the MVA. This new method is therefore capable of diagnosing as well as following the course of mitral stenosis. It must be taken into consideration that planimetry by MRI slightly overestimates the MVA as compared to cardiac catheterization.
Anatomy, Cross-Sectional↗
Intra-arterial MR angiography in the iliac system: initial clinical experience with 25 patients.
The aim of this study was to evaluate intra-arterial magnetic resonance angiography (MRA) of the iliac arteries. Therefore, 25 consecutive patients (17 male, 8 female) suffering from symptomatic occlusive disease of the lower limbs were investigated prospectively. Catheter angiography was performed before MRA and served as the standard of reference. Contrast-enhanced intra-arterial MRA was performed using a 1.5 Tesla MRI system. Contrast agent (gadodiamide) was injected by a conventional pigtail-shaped angiography catheter placed in the abdominal aorta. Vascular lesions were assessed by four investigators. The degree of stenosis was compared with the findings of conventional catheter angiography. Additionally, the diagnostic quality of the MR angiograms was assessed by the investigators using a semi quantitative five-point scale. All lesions shown by catheter angiography were detected and correctly localized by intra-arterial MRA. MR angiograms exhibit a specificity of 95% and a sensitivity of 96% for stenoses of 50% or more. The diagnostic quality of the images was judged from good to excellent, on average. Intra-arterial MRA exhibits a specificity and sensitivity comparable with intravenous angiography. The image quality appears to be adequate for supporting MR-guided vascular intervention.
Adult↗
[Diagnosis of chronic mesenterial artery ischemia. Re the article from DMW 3/2005].
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Angiography, Digital Subtraction↗
[Role of computed tomography and magnetic resonance imaging in the diagnosis of hepatitis and liver cirrhosis].
Computed tomography (CT) and Magnetic Resonance Imaging (MRI) have no significant impact in the evaluation of diffuse liver disease. Cirrhosis and hepatitis are not of specific imaging findings, the image of cirrhosis is depending on degree of disease. Nodular lesions are frequent findings in cirrhotic livers. For differentiation of regenerative nodules, dysplastic nodules and hepatocellular carcinoma CT and MRI are playing their role in localization and characterization of these lesions. Sensitivity and specificity are varying, depending on the technical applications of CT and MRI, and the application of contrast materials. MRI is superior in characterizing the lesions due to the different appearance of the lesions in different sequences. CT is superior as the staging modality. Complications of cirrhosis like ascites, varices of the oesophageal veins are diagnosed. CT and MRI are necessary when interventional or surgical procedures are planned or for therapy surveillance.
Ascites↗
[Diffusion-weighted imaging in the diagnostic evaluation of the hydrocephalus in patients with acute or chronic increase in cerebral pressure].
PURPOSE: To investigate whether diffusion-weighted imaging (DWI) in magnetic resonance imaging (MRI) provides additional information about the periventricular white matter for the assessment of hydrocephalus. MATERIALS AND METHODS: Sixteen MRI examinations (11 with acutely increased cerebral pressure, 5 without symptoms) on 15 patients with hydrocephalus (4 patients with communicating hydrocephalus and 11 patients with obstructive hydrocephalus) were analyzed. One symptomatic patient subsequently became asymptomatic. We investigated the "apparent diffusion coefficient" (ADC) in the subcortical and periventricular white matter. The ADCs of the study patients were compared with those of a healthy control group. RESULTS: Symptomatic patients with hydrocephalus, 6/11 showed periventricular edema and a significantly higher ADC values in the periventricular region than in the subcortical white matter. 5/11 symptomatic patients showed significantly higher ADC values even in the absence of periventricular interstitial edema (both groups contained patients with communicating and obstructive hydrocephalus). All 5 asymptomatic patients with hydrocephalus did not have a significantly higher ADC values in the periventricular region. CONCLUSION: In patients with hydrocephalus and acutely increased cerebral pressure, DWI showed a significantly higher ADC values in the periventricular region even without visible interstitial edema on conventional MRI sequences.
Adolescent↗
Detection rate and efficiency of lymph node assessment with axial and coronal image reading based on 16 row multislice CT of the neck.
PURPOSE: Multislice CT (MSCT) has the advantage of isotropic volumetric data acquisition which allows high resolution data reconstruction in the axial and coronal plane. We evaluate the accuracy and efficiency of coronal reconstruction compared to axial reconstructions of a routinely performed CT scan exemplary in neck lymph node assessment performed on a 16 row MSCT. MATERIAL AND METHODS: Contrast enhanced neck MSCT of 24 patients with known lymphoma were evaluated prospectively for lymph node assessment. 4 blinded readers evaluated the axial and coronal reconstructions of the same patient. Neck lymph nodes larger than 10 mm were evaluated by their anatomical region (deep jugular chain, submandibular, nuchal). Time for axial and coronal image evaluation was assessed. Detection rate was compared with consensus reading as gold standard. RESULTS: In consensus reading 169 enlarged lymph nodes in the deep jugular chain were found. Detection rate for axial image interpretation was 36.1 % with 54.9 % in coronal reading. Assessing the submandibular lymph nodes (n = 45) axial interpretation revealed 53.9 % with 36.1 % in coronal reading. Evaluation time for axial reading was in all but one reader significantly longer (mean 176 seconds) than in coronal reading (mean 129 seconds). CONCLUSION: Coronal image reading improves the detection rate of cranio-caudal oriented structures. Considering representatively neck lymph nodes in the deep jugular chain the image interpretation time is significantly reduced. Still axial reading remains necessary for assessing axially oriented structures such as the submandibular region in the neck.
Adult↗
Intra-arterial magnetic resonance angiography of the iliac arteries: clinical experience using two different protocols.
PURPOSE: To assess the feasibility of intra-arterial magnetic resonance angiography (iaMRA) with two different protocols. MATERIAL AND METHODS: Twenty patients were prospectively examined after digital subtraction angiography. Contrast-enhanced iaMRA was performed using a 1.5T magnetic resonance imaging (MRI) system. Contrast agent (gadodiamide) was injected through a conventional angiography catheter placed in the abdominal aorta. The patients were randomized into two groups each comprising 10 patients. Group 1 was examined with a FLASH-3D (fast low-angle shot) sequence, allowing the center of the k-space to be acquired 0.5 s after initiation of the measurement. Group 2 was examined with the identical sequence, but the center of the k-space was acquired after 8.7 s. The increase in the intravascular signal intensity was determined and the diagnostic value of the angiograms was independently scored by 4 investigators using a 5-point scale. RESULTS: Nineteen of 20 MRAs were scored as diagnostic; only 1 was scored as non-diagnostic by 2 observers. The diagnostic value of the angiograms of group 2 was judged superior to that of group 1 owing to a more homogeneous intravascular contrast distribution. CONCLUSION: Intra-arterial MRA is feasible. The diagnostic value of angiograms using a flash sequence with center of the k-space acquisition after 8.7 s ranged from good to excellent. This sequence is appropriate for iaMRA of iliac arteries to support MR guided intervention.
Adult↗
Management of acute pancreatitis: from surgery to interventional intensive care.
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Acute Disease↗
Comparison of magnetic resonance imaging colonography with conventional colonoscopy for the assessment of intestinal inflammation in patients with inflammatory bowel disease: a feasibility study.
AIM: Magnetic resonance imaging (MRI) based colonography represents a new imaging tool which has mainly been investigated for polyp screening. To evaluate this approach for patients with inflammatory bowel disease (IBD), we compared MRI based colonography with conventional colonoscopy for assessing the presence and extent of colonic inflammation. PATIENTS AND METHODS: In 22 consecutive patients with suspected or known IBD, MRI colonography was performed immediately before conventional colonoscopy. After bowel cleansing, a T1 positive contrast agent was applied rectally. In addition to T2 weighted sequences, T1 weighted two dimensional and three dimensional Flash acquisitions as well as volume rendered virtual endoscopy were performed. All images were evaluated with regard to typical MRI features of inflammation. The results were compared with colonoscopy findings. RESULTS: Distension and image quality was assessed as good to fair in 97.4% of all colonic segments. Only four of 154 segments were considered non-diagnostic. With colonoscopy serving as the gold standard, the sensitivity for correctly identifying inflammation on a per segment analysis of the colon was 31.6% for Crohn's disease (CD) and 58.8% for ulcerative colitis (UC). In CD, in most cases mild inflammation was not diagnosed by MRI while in UC even severe inflammation was not always depicted by MRI. Virtual endoscopy did not add any relevant information. CONCLUSION: MRI based colonography is not suitable for adequately assessing the extent of colonic inflammation in patients with IBD. Only severe colonic inflammation in patients with CD can be sufficiently visualised.
Adult↗
Diffusion-weighted imaging with calculated apparent diffusion coefficient of enhancing extra-axial masses.
BACKGROUND AND PURPOSE: Sometimes intracranial contrast-enhancing tumors like meningiomas, metastases, lymphomas, and schwannomas can mimic each other. It was the aim of the present study to investigate if intracranial contrast-enhancing lesions can be reliably differentiated with the help of diffusion-weighted imaging with calculated apparent diffusion coefficients (ADCs). METHODS: 29 patients (ages ranging from 22 to 82 years, mean age of 58.6 years) were included. Nine meningiomas, 7 metastases, 6 lymphomas, and 7 schwannomas were investigated. The ADC value in the lesions and in the perifocal edema was analyzed. RESULTS: For the lymphomas, the authors measured the lowest ADC values in the contrast-enhancing part (0.59 +/- 0.09 . 10(-3) mm2/sec). The meningiomas showed a mean ADC value of 0.98 +/- 0.18 . 10(-3) mm2/sec. The schwannomas and metastases showed higher ADC values of 1.33 +/- 0.28 . 10(-3) mm2/sec and 1.05 +/- 0.20 . 10(-3) mm2/sec. The authors saw a statistically significant difference between lymphomas, meningiomas, and metastases concerning the ADC values in the contrast-enhancing part. CONCLUSIONS: In spite of a small sample size and partly a wide range of values, the authors found statistically significant differences between meningiomas, metastases, and lymphomas concerning ADC values. Nevertheless, a differentiation of these lesions only with the help of ADC values seems questionable.
Adult↗
Degenerative diseases of the cervical spine: comparison of a multiecho data image combination sequence with a magnetisation transfer saturation pulse and cervical myelography and CT.
Assessing degenerative disease in the cervical spine remains a challenge. There is much controversy about imaging the cervical spine using MRI. Our aim in this prospective study was to compare a T2*-weighted 2D spoiled gradient-echo multiecho sequence (MEDIC) with a magnetisation transfer saturation pulse with cervical myelography and postmyelographic CT. Using an assessment scale we looked at the vertebral bodies, intervertebral discs, neural foramina, anterior and posterior nerve roots, grey matter, ligamentaflava, oedema in the spinal cord and stenosis of the spinal canal. We also evaluated postmyelography CT and the MEDIC sequence for assessing narrowing of the neural foramina in a cadaver cervical spine. We examined 67 disc levels in 18 patients, showing 18 disc prolapses and 21 osteophytes narrowing the spinal canal or the neural foramina. All MRI studies showed these abnormalities findings equally well. Postmyelography CT was significantly better for showing the bony structures and the anterior and posterior nerve roots. The MEDIC sequence provided excellent demonstration of soft-tissue structures such as the intervertebral disc and ligamentum flavum. No statistical differences between the imaging modalities were found in the assessment of narrowing of the neural foramina or the extent of spinal stenosis. The cadaver measurements showed no overestimation of abnormalities using the MEDIC sequence.
Adult↗
Contrast-enhanced ultrasound allows for interventions of hepatic lesions which are invisible on convential B-mode.
BACKGROUND AND AIMS: Contrast harmonic imaging significantly increases the detectability of liver lesions which are invisible on conventional B-mode sonography. With the introduction of contrast agents, which can be visualized at low mechanical index (low-MI), continuous real time observation of liver lesions under contrast conditions is possible. We addressed the question whether contrast-enhanced sonography allows for intervention of hepatic lesions impossible to detect on conventional B-mode imaging. PATIENTS AND METHODS: We evaluated twelve patients with hepatic tumors or abscesses, which could not be analyzed and punctured under fundamental B-mode guidance. The ultrasound contrast agent BRI was used for detection of the hepatic lesions under contrast harmonic imaging (CHI) conditions with phase inversion at low-MI. RESULTS: In eleven out of twelve patients interventions under CHI conditions were successful, as proven by histological, microbiological or tumor marker analysis. The puncture needles were visible in all cases. With an algorithm for optimizing the puncture conditions at low-MI CHI the biopsies can be performed in two steps. CONCLUSIONS: Our results show that biopsies of liver lesions under real-time continuous CHI at low-MI are feasible.
Biopsy, Needle↗
Feasibility of MR-guided angioplasty of femoral artery stenoses using real-time imaging and intraarterial contrast-enhanced MR angiography.
PURPOSE: To show the feasibility of magnetic resonance (MR) for guided interventional therapy of femoral and popliteal artery stenoses with commercially available materials supported by MR real-time imaging and intraarterial MR angiography. MATERIALS AND METHODS: Three patients (1 female, 2male), suffering from symptomatic arterial occlusive disease with stenoses of the femoral (n = 2) or popliteal (n = 1) arteries were included. Intraarterial digital subtraction angiography was performed in each patient pre- and post-interventionally as standard of reference to quantify stenoses. The degree of the stenoses reached from 71 - 88 %. The MR images were acquired on a 1.5 T MR scanner (Magnetom Sonata; Siemens, Erlangen, Germany). For MR-angiography, a Flash 3D sequence was utilized following injection of 5 mL diluted gadodiamide (Omniscan; Amersham Buchler, Braunschweig, Germany) via the arterial access. Two maximum intensity projections (MIP) were used as road maps and localizer for the interactive positioning of a continuously running 2D-FLASH sequence with a temporal solution of 2 images per second. During the intervention, an MR compatible monitor provided the image display inside the scanner room. Safety guidelines were followed during imaging in the presence of a conductive guidewire. The lesion was crossed by a commercially available balloon catheter (Wanda, Boston Scientific; Ratingen, Germany), which was mounted on a 0.035" guidewire (Terumo; Leuven, Belgium). The visibility was provided by radiopaque markers embedded in the balloon and was improved by injection of 1 mL gadodiamide into the balloon. After dilation, the result was checked by intraarterial MR angiography and catheter angiography. RESULTS: The stenoses could be correctly localized by intraarterial MR angiography. There was complete correlation between intraarterial MR angiography and digital subtraction angiography. The combination of guidewire and balloon was visible and the balloon was placed correctly to cover the entire stenoses. Balloon dilation reduced the degree of stenosis about 45 % on average. A prolonged dilation was necessary in one patient due to a relevant residual stenosis, which was recognized by intraarterial MR angiography. CONCLUSION: MR-guided balloon dilatation of femoral and popliteal artery stenoses supported by real time imaging and intraarterial MR angiography is feasible with commercially available materials in the above mentioned way.
Aged↗
[Reimbursement of radiologically guided vascular interventions within the DRG-system: what will change?].
PURPOSE: To evaluate reimbursement within the DRG-system ("diagnosis-related groups") compared with traditional reimbursement for interventional therapy of hospitalized patients. MATERIALS AND METHODS: Reimbursement calculation was prospectively analyzed in two respects for 30 consecutive patients who underwent percutaneous transluminal angioplasty (PTA) of the lower extremity arteries: (1) based on the DRG-system; (2) based on the traditional system. Additional evaluation was performed for five further, typical vascular procedures on the basis of real documentation and calculation data (stenting of the carotid artery, fibrinolytic therapy of basilar artery occlusion, stenting of renal artery stenosis, angioplasty of hemodialysis-shunt stenosis and aspiration thrombectomy of an infrapopliteal arterial occlusion). RESULTS: In our hospital, the introduction of the DRG system would reduce reimbursement by approximately 1100 euro per PTA patient. However, the other vascular radiological procedures can be expected to increase the payments by up to 4500 euro. CONCLUSION: To minimize imminent reduction of reimbursement for patients with peripheral PTA, complete documentation and economical patient management is mandatory. Payment may increase significantly for patients with the other reported vascular interventional procedures.
Adult↗