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ABSTRACT: To assess prospectively the agreement of magnetic resonance (MR) pulmonary perfusion with single-photon emission computed tomography (SPECT) perfusion for perfusion defects down to the subsegmental level in patients with suspected pulmonary embolism (PE).
In 41 patients with suspected PE, contrast-enhanced MR pulmonary perfusion (3D-FLASH, TR/TE 1.6/0.6 ms) was compared to SPECT perfusion on a per-examination basis as well as at the lobar, segmental, and subsegmental level.
The MRI protocol was completed in all patients, and mean examination time was 3 min 56 s. MR perfusion showed a very high agreement with SPECT (kappa value per examination 0.98, and 0.98, 0.83, and 0.69 for lobar, segmental, and subsegmental perfusion defects, respectively). Of 15 patients with PE, MR perfusion detected 14 cases.
The very high agreement of MR perfusion with SPECT perfusion enables the detection of subtle findings in suspected PE.
Acta Radiologica 12/2006; 47(9):933-40. · 1.37 Impact Factor
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ABSTRACT: To retrospectively assess the indication for thoracic real-time MRI, demonstrate typical findings, analyze the diagnostic potential in subgroups with suspected pulmonary embolism (PE) and aortic dissection (AD), and describe the influence of real-time MRI on the role of MRI in acute thoracic diseases.
From July 2001 to February 2005, real-time MRI was applied in 2,256 examinations in 1,714 patients. MRI was the primary diagnostic modality for these thoracic diseases as computed tomography has been available only since 2003. Characteristics of the TrueFISP sequence applied were: TR/TE/flip angle 3.1 ms/1.6 ms/59 degrees , respectively. FOV 340 - 360 mm, matrix size 156 to 192 x 256 pixels, slice thickness 3 to 4 mm, slices overlapped by 50 %. Acquisition time was 0.4 to 0.5 s per image. Three hundred and twenty transverse, coronal and sagittal images were acquired in three minutes. No breath holding, and only minimal patient cooperation, was required. Turbo-spin-echo sequences as well as ECG-gated and contrast-enhanced sequences were added depending on the indication.
Most common indications were: acute thoracic nonspecified disease (n = 276, 12.24 %), PE (n = 573, 25.4 %), bleeding (n = 154, 6.8 %), AD (n = 222, 9.8 %), topographic information in complex findings (n = 654, 29.0 %). Real-time MRI was the sole MRI technique applied in 180 examinations (8.0 %), ECG-gated real-time MRI was applied in 87 examinations and breath hold was used in 107 examinations. PE was diagnosed in 181 examinations; reference techniques (MRI, computed tomography, single photon emission computed tomography) confirmed 170 of these and detected 19 more cases (sensitivity 90.0 %, specificity 97.1 %). Real-time MRI detected 141 suspected AD and 53 more nonsuspected AD. Of these, 191 were confirmed by other MRI techniques, surgery or clinical course (98.5 %). Real-time MRI coincidentally detected 56 pulmonary tumors, all were confirmed with computed tomography. Thus, especially vascular diseases could be easily assessed with real-time MRI, while computed tomography had advantages in the evaluation of the lung parenchyma.
Real-time MRI both enables emergency MRI examinations for thoracic diseases in clinical patients in unstable condition and allows an explorative style of working in patients with nondefined acute thoracic diseases.
RöFo - Fortschritte auf dem Gebiet der R 12/2005; 177(11):1513-21. · 2.76 Impact Factor
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ABSTRACT: Ankylosing spondylitis (AS) is characterised by chronic inflammation and partial ossification, yet vertebral fractures due to osteoporosis, although common, are frequently unrecognised. The aim of this study was to (1) show the frequency of changes in the progress of osteopenia/osteoporosis in AS depending on duration and stage of the disease and (2) assess the ranking of two different methods of bone density measurement in this clinical pattern. We measured bone density in 84 male and female patients with both dual X-ray absorptiometry (DXA) and single energy quantitative computed tomography (SE-QCT). In the initial and advanced stages of the disease, a high decrease in axial bone density could be verified (DXA: osteopenia in 5% and osteoporosis in 9.2%; SE-QCT: osteopenia in 11.8% and osteoporosis in 30.3%). Peripheral bone density decrease as in osteopenia could be proven in 17.6% by DXA measurement. With SE-QCT, a decrease in vertebral trabecular bone density could already be observed in the initial stage and continued steadily during the course of the disease; cortical bone displayed the same trend up to stages of ankylosis. With DXA, valid conclusions are more likely to be expected in less marked ankylosing stages of AS. In stages of advanced ankyloses in the vertebral region (substantial syndesmophytes), priority should be given to SE-QCT, due to the selective measurement of trabecular and cortical bone. The DXA method often yields values that are too high, and the replacement of vertebral trabecular bone by fatty bone marrow is not usually recorded as standard. There may already be an increased risk of bone fracture in AS in osteopenia on DXA along with an osteoporosis already established on SE-QCT.
Rheumatology International 12/2005; 26(2):115-20. · 1.88 Impact Factor
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ABSTRACT: Integration of MR venography in a comprehensive MR imaging protocol in patients with suspected pulmonary embolism (PE) and evaluation of contrast media dosage, timing and postprocessing for diagnostic accuracy.
Forty-eight consecutive inpatients with suspected PE or deep vein thrombosis were examined by MR venography according to one of the following protocols: protocol I: MR venography only, 0.25 mmol/kg body weight (BW) Gadopentate dimeglumine (Gd-DTPA) as single dose, bolus timing; protocol II: MR angiography of pulmonary arteries with a cumulative dosage of 0.25 mmol/kg contrast media, modification of coil setting for MR venography without further contrast media application; protocol III: as protocol II but with 0.125 mmol/kg BW, followed by MR venography. Signal-to-noise ratio, contrast-to-noise ratio, number of definable vascular segments and image quality were evaluated. The results were compared to conventional bilateral venography.
All MR venography examinations were of diagnostic quality and the examination time was below 10 min. MR venography could be performed in all 48 patients compared to 43 of 48 patients for conventional venography. Significantly more superficial and deep veins of the leg could be visualized by MR venography (94 % compared to 83 % for conventional venography). Sensitivity and specificity were 100 % and 92 %, respectively. Quality differed significantly between 0.125 mmol/kg (protocol III) and 0.25 mmol/kg Gd-DTPA (protocols I and II) while timing did not influence quality (protocol I vs. II).
An integrated MR diagnostic evaluation of pulmonary arteries and veins of the leg is feasible in patients with suspected PE. MR venography with 0.25 mmol/kg Gd-DTPA reliably depicts the venous system of the leg more completely than conventional venography with at least equivalent diagnostic confidence.
RöFo - Fortschritte auf dem Gebiet der R 08/2004; 176(7):976-84. · 2.76 Impact Factor
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ABSTRACT: Brain edema is a life-threatening consequence of stroke and leads to an extension of the affected tissue. The space-occupying effect due to brain edema can be quantified in rat stroke models with the use of MRI. The present study was performed to test 2 hypotheses: (1) Can quantification of the space-occupying effect due to brain edema serve as a noninvasive measure for brain water content? (2) Does morphometric assessment of brain swelling allow determination of true infarct size on MRI after correction for the space-occupying effect of edema?
Thirty rats were subjected to permanent suture middle cerebral artery occlusion. MRI was performed after 6 or 24 hours, and hemispheric swelling was assessed morphometrically. Interobserver and intraobserver agreements were determined for MRI measurements. In study I, the space-occupying effect due to brain edema was correlated with the absolute brain water content by the wet/dry method. In study II, lesion volumes corrected and uncorrected for edema were calculated on MRI and on TTC staining and compared.
Interobserver and intraobserver agreements for MRI measurements were excellent (r>or=0.97). Brain water content and hemispheric swelling correlated well after 6 and 24 hours (r>or=0.95). Corrected lesion volumes correlated with r=0.78 between TTC staining and MRI. Without edema correction, lesion volumes were overestimated by 20.3% after 6 hours and by 29.6% after 24 hours of ischemia.
Morphometric assessment of hemispheric swelling on MRI can determine the increase in absolute brain water content noninvasively and can also provide ischemic lesion volumes corrected for brain edema.
Stroke 02/2004; 35(2):566-71. · 5.73 Impact Factor
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American Journal of Roentgenology 08/1999; 173(1):246. · 2.78 Impact Factor
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ABSTRACT: Evaluation of technical success rate, long-term outcome and initial complication rate in patients with fluoroscopically guided port implantation.
Between January 1994 and April 1997 124 ports were implanted under fluoroscopic guidance in 120 patients. Indications for port implantation were anti-cancer chemotherapy, antibiotic and supportive therapy in patients with tumours or cachexia.
Implantation was technically successful in 98.4% of the patients. We had a 3.2% minor complication rate that did not necessitate further treatment. One pneumothorax required a chest tube (0.8%). During a total of 17,534 days, complications occurred in 10.8% of all ports, 6.9% of the ports had to be explanted because of these complications.
Insertion of ports under fluoroscopic guidance has a low complication rate and good long-term results. The rate of 93.1% of functioning ports is superior to that reported in other studies. It is less costly and has a lower complication rate than surgical implantation. Therefore it seems to be the method of choice for patients requiring long-term subcutaneous venous access for chemotherapy or supportive therapy in malignant tumours or other emaciating diseases.
RöFo - Fortschritte auf dem Gebiet der R 08/1998; 169(1):63-7. · 2.76 Impact Factor
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ABSTRACT: The aim of the present study was to evaluate the efficacy of fluoroscopically controlled implantation of subcutaneous tunneled single- or double-lumen-catheters for short- and long-term dialysis.
In total, 104 patients were implanted with either a single-lumen Demer catheter or a Permcath double-lumen catheter into the subclavian vein under fluoroscopic control.
In 99 of 104 cases (= 95.2%) the implantation remained without complications. Implantation-related occurrences included one pneumothorax, one mediastinal haematoma and one death. 61.5% of the indwelling catheters remained in situ for the intended duration. In 78% of the patients, dialysis was carried out to completion. 37 explantations (38.3%) were required due to various factors including infection (5), thrombosis (3), dislocation (9) and malfunction (20). The average duration of implantation was 59.1 days (range 1-851 days).
Fluoroscopic-controlled implantation of subcutaneous tunneled catheters for dialysis is superior to surgically implanted catheters with regard to lower rates of infections and is equally reliable in respect of rates of complication and patency. Thus, this mode of implantation is a safe and reliable alternative to other procedures as access for haemodialysis.
RöFo - Fortschritte auf dem Gebiet der R 04/1997; 166(3):230-2. · 2.76 Impact Factor
