[Quality criteria of digital subtraction angiography of the trunk of the body]. / Qualitätskriterien der digitalen Subtraktionsangiographie am Körperstamm.

The presently valid quality criteria of digital subtraction angiography in the body trunk area are described. The indications for intravenous and intraarterial examinations are explained; these are closely connected with the respective demands. The problem levels are analysed and update technical and methodical solutions are offered.

[MRT in degenerative diseases of the cervical spine]. / MRT bei degenerativen Halswirbelsäulen-erkrankungen.

MRI has grown increasingly important in recent years in diagnosis of degenerative disease of the cervical spine, due to improvements of method that have made it a valuable diagnostic tool. The following contribution gives a brief introduction to the pathophysiology of degenerative changes in the cervical vertebral column and to the indications for MRI, describing within the framework of imaging the present state of MR examination technique. The ranking of the various gradient echo sequences, of the 3D methods and of the administration of contrast media in cervical myelopathy and radiculopathy is discussed.

[Initial experiences with combined balloon angioplasty and rtPA thrombolysis in dialysis shunt failure]. / Erste Erfahrungen mit der kombinierten Ballonangioplastie und rtPA-Thrombolyse bei Dialyseshuntversagen.

The 23 interventions performed by us on 18 patients had a very high success rate both in intraarterial lysis therapy of obstructed haemodialysis shunts and in balloon angioplasty (19/23). Shunt failure had to be primarily treated by surgery in 3 cases only. The complications were confined to a rupture of a vessel that required surgical care. 14 shunts were found to be patent in a total of 18 patients (18 being of course as small patient group). Our experience leads us to believe that patients suffering from shunt insufficiency should always be primarily treated endoluminally if angiography confirms that intervention is possible. Surgical intervention is always advisable even if the result may occasionally be negative in a few rare cases.

[Primary femoral recanalization using a slowly rotating catheter system]. / Primäre femorale Rekanalisation mit einem langsam rotierenden Kathetersystem.

Over a period of 2 years, 26 patients with chronic occlusions of the superior femoral and popliteal arteries were referred for recanalization. In two cases, the origin of the superior femoral artery could not be detected. A primary recanalization was achieved in 21 of 24 patients by the catheter system used by us (Viadyn). A stent (extensor) had to be implanted in one case because of a considerable lesion of the intima. A short-term clot lysis was indicated for another patient. On the basis of our results, rotation angioplasty with a slowly rotating catheter system seems to be the therapeutic method of choice for chronic arterial occlusions in the thigh.

[Diffuse demineralization of the lumbar spine. Magnetic resonance tomography studies of osteoporosis and plasmacytoma]. / Diffuse Demineralisation der Lendenwirbelsäule. Magnetresonanztomographische Untersuchungen bei Osteoporose und Plasmozytom.

On plain radiographs, diffuse infiltration of the spine in multiple myeloma may present as diffuse demineralization. Differentiation from osteoporotic changes is then difficult. 15 patients with multiple myeloma and 15 patients with osteoporosis were prospectively examined by MRI using plain and contrast enhanced gradient echo techniques. Examinations were evaluated for lesions and diagnosis was made by two independent observers. Contrast enhancement was visible in lesions detected in myeloma patients and in compression fractures. Fractures could be differentiated from malignant lesions by the fact that there was no multiplicity of enhancing lesions. Contrast enhanced opposed phase gradient echo sequences seem suited for the detection of vertebral involvement in myeloma.

Contrast-enhanced transcranial Doppler US with a new transpulmonary echo contrast agent based on saccharide microparticles.

The purpose of this first patient study (phase II) was to evaluate the clinical usefulness of a new echo contrast agent at transcranial Doppler ultrasonography (US). Twenty patients were selected from a group of 242 patients undergoing conventional transcranial Doppler US who had low (n = 18) or absent (n = 2) Doppler signals from the middle cerebral artery (MCA). The extent and duration of Doppler signal increase was measured in 30 MCAs and in 14 basilar arteries following the intravenous injection of a transpulmonary galactose microparticle suspension (SH U 508 A) at three concentrations (200, 300, and 400 mg/mL). Doppler waveform analysis became possible in 93% (28 of 30) of the MCAs following injection. The maximal increase in average Doppler signal intensity (11 dB at 200 mg/mL, 15 dB at 300 mg/mL, and 17 dB at 400 mg/mL) and the increase in average duration of the signal enhancement (163 seconds at 200 mg/mL, 219 seconds at 300 mg/mL, and 240 seconds at 400 mg/mL) depended on contrast agent concentration. Doppler waveform analysis became possible in 79% (11 of 14) of the basilar arteries. The intravenous injection of this new echo contrast agent markedly increases Doppler signal intensity in patients with nondiagnostic results at conventional Doppler US.

[MRT in cervical disk herniation: plain vs. contrast-enhanced images]. / MRT bei zervikalen Bandscheibenvorfällen: native vs. kontrastmittelunterstützte Aufnahmen.

Aim of this study was to assess the value of Gd-DTPA administration in MRI of cervical disk herniations. In 34 patients, showing 40 cervical disk herniations, plain proton density- and T1-weighted as well as contrast-enhanced T1-weighted 2D-FLASH images were generated. Contrast between the herniated material and the CSF already was sufficient without administration of Gd-DTPA in all cases. Sufficient contrast between the herniations and the intraforaminal structures was obtained in 13/40 cases and 40/40 cases on plain and contrast-enhanced images, respectively. Definition of the herniated disks was judged to be sufficient in 30/40 cases on plain images and 40/40 cases on contrast-enhanced images. The diagnostic value of the images was improved in 3/12 lateral and 7/8 intraforaminal herniations by contrast administration, whereas there was no significant increase in diagnostic value in posterior or posterolateral herniations. As a result, Gd-DTPA administration is recommended if definition of lateral and intraforaminal disk herniations in MRI is poor.

[The magnetic resonance tomographic differential diagnosis between reactively enlarged lymph nodes and cervical lymph node metastases]. / Magnetresonanztomographische Differentialdiagnostik zwischen reaktiv vergrösserten Lymphknoten und Halslymphknotenmetastasen.

A prospective study was carried out involving 27 patients to determine whether MRT can distinguish between lymph node metastases and reactive lymph node enlargement. The results of MRT were compared with the pathological findings. Using T1 and T2 weighted sequences and proton density sequences it was not possible to differentiate between reactively enlarged lymph nodes and lymph node metastases. Following the administration of Gd-DTPA the observation of central hypo-intensity with marginal hyper-intensity is a reliable sign of a lymph node metastasis. Using the criterion of length greater than 10 mm for lymph node metastases results in a specificity of 32% and sensitivity of 75%. The use of the sonographic maximal/cross measurement quotient > 2 in the axial/coronary/sagittal dimension improves specificity and sensitivity to 94%.

[Magnetic resonance tomographic screening studies of the bone marrow with gradient-echo sequences. II. Gadolinium-DTPA-supported studies of plasmocytoma patients]. / Magnetresonanztomographische Screeninguntersuchungen des Knochenmarkes mit Gradientenecho-Sequenzen. II. Gadolinium-DTPA-unterstützte Untersuchungen von Plasmozytom-Patienten.

MR imaging was performed in 19 patients with proven multiple myeloma. Both plain and Gd-DTPA enhanced in-phase and opposed-phase gradient-echo techniques were used (0.1 mmol Magnevist/kg body weight). Plain, opposed-phase imaging demonstrated more lesions than plain in-phase imaging (35 vs. 16); enhanced opposed-phase imaging demonstrated more lesions than plain opposed-phase and enhanced in-phase imaging (47 vs. 35 and 17 lesions). These results suggest that enhanced opposed-phase images which have a high contrast between normal and infiltrated bone marrow are especially suited for MR screening in multiple myeloma.

["Surgical projection" in the gadolinium-DTPA (Gd-DTPA)-supported NMR tomographic diagnosis of lateral lumbar disk prolapse]. / Die "chirurgische Projektion" in der Gadolinium-DTPA(Gd-DTPA)-unterstützten kernspintomographischen Diagnostik des lateralen lumbalen Bandscheibenvorfalls.

In a group of 25 patients the coronal views of plain and Gd-DTPA-enhanced MRI studies were correlated with CT and operative findings. All series included sagittal, transverse and coronal FLASH sequences (GE 500/6, flip angle 70 degrees), sagittal proton density-(SE 2500/15) and T2-(SE 2500/70) weighted images. MR diagnosis proved to be correct in all cases. Compared to CT and axial MRI herniated disk material in the lateral intravertebral space and its relationship to nerve roots was demonstrated more clearly on coronal views.

[Postoperative nuclear magnetic resonance tomography of the talocrural joint after external syndesmorrhaphy]. / Postoperative kernspintomographische Untersuchung des oberen Spruggelenks nach Aussenbandnaht.

20 patients with acute traumatic rupture of the anterior talofibular ligament and ligamental suture were studied postoperatively by MRI. MR results were correlated with stress x-ray studies. We found a normal anterior talofibular ligament in eight cases. However, stress x-ray images showed normal stability of the ankle joint in eighteen cases. In six patients the anterior talofibular ligament was thickened, in another six cases it could not be separated from scar tissue. Therefore MR imaging of ankle ligaments did not allow a diagnosis of their function. Nevertheless, sequelae of the ankle trauma such as osteochondrosis, exudation into the ankle joint and tendovaginitis of the flexor muscles were sensitively visualised by MR.

[More rapid MRT with T2-weighted spin-echo sequences through variation of the flip angle]. / Schnellere MRT mit T2-gewichteten Spinecho-Sequenzen durch Variation des Anregungswinkels.

In the present study the influence of the flip angle on image contrast in spin echo imaging was investigated. It was evaluated, whether variation of the flip angle allows for shorter repetition and imaging times in T2-weighted spin echo sequences. 10 patients with cerebral white matter lesions were investigated with an 1.5 Tesla whole body tomograph using a conventional double-spin echo sequence (TR = 2500 ms, TE = 15 and 70 ms) and time-optimized double-spin echo sequences (TR = 1900 ms, TE 15 and 70 ms) at flip angles of 90, 80, 70, 60 and 50 degrees. A reduction of the flip angles resulted in a decrease of T1-weighting and a relative increase of T2-weighting of the images. Despite the reduced repetition time at a flip angle of 70 degrees visually and quantitatively assessed contrast between lesions and brain as well as image artifacts of the time-optimized sequence were comparable to the conventional spin echo sequence; however, imaging time was shortened about 25%.

[Magnetic resonance tomographic screening studies of the bone marrow with gradient echo sequences: (I) the contrast relations of phase-identical and phase-shifted gradient echo sequences. Studies on probands and pathological-anatomical preparations]. / Kernspintomographische Screeninguntersuchungen des Knochenmarkes mit Gradientenecho-Sequenzen: (I) Kontrastverhältnisse phasenidentischer und phasenverschobener Gradientenecho-Sequenzen. Untersuchungen von Probanden und pathologisch-anatomischen Präparaten.

Anatomical specimens and normal persons were studied by gradient echo MR imaging to determine the influence of different echo times (TE) on bone marrow contrast. First of all, six normal persons were studied to determine specific echo times for in-phase and opposed-phase states. Using different sequences bone marrow contrast in isolated femoral bones was determined and compared to results of pathological exams. Red bone marrow had no signal on opposed-phase images; contrast between red and yellow marrow was higher on opposed-phase than on in-phase images. Bone marrow lesions can be expected to be visualised with high signal on opposed-phase images; this technique should be especially suited for MR imaging of bone marrow.

Spinal cord cavities: differential-diagnostic criteria in magnetic resonance imaging.

MRI examinations of 30 patients with idiopathic syringomyelia and 10 patients with cavities associated with an intramedullary neoplasm were evaluated with respect to typical MRI features in both groups. All tumor-associated cases resembled the idiopathic syringomyelias in some portions of the cavity. At the tumor site, however, tumor-associated cases demonstrated typical findings: the cavities showed abrupt changes of diameter (10/10) and position (8/10) and the surrounding spinal cord demonstrated an uneven thickness (10/10), an increased signal intensity on T2-weighted images (10/10) and pathological contrast enhancement (7/7). Displacement of cerebellar tonsils below the level of the foramen magnum (21/30) and enlargement of the spinal canal (7/29) were characteristic features of idiopathic cases. In conclusion, MRI provides valuable criteria to differentiate between idiopathic and tumor-associated cavities.

[Magnetic resonance tomographic and sonographic imaging of the ankle in marathon runners]. / Kernspintomographische und sonographische Befunde der Knöchel von Marathonläufern.

Calcaneus tendons and ankles of 25 practising marathon runners were investigated by sonography and MR. We applied a 7.5 MHz transducer for sonography. Axial and sagittal T1-weighted, proton density-weighted, and T2-weighted SE images were performed. MR proved superior to sonography. Degenerative alterations of the calcaneus tendon, tendovaginitis of the flexor hallucis longus muscle, joint effusions and cartilage disease were diagnosed by MR but remained undetected by sonography.

[A NMR tomographic follow-up assessment of the replacement plastic repair of the anterior cruciate ligament with an autologous ligamentum patellae transplant]. / Kernspintomographische Verlaufsbeurteilung der vorderen Kreuzbandersatzplastik mit einem autologen Ligamentum-patellae-Transplantat.

Reconstruction of the anterior crucial ligament can be performed by using an autogenous transplant from the patellar ligament. Employing postoperative MR investigation, reaction of the non-vascularised tendon was studied. In 16 patients 20 knees were investigated by applying a 1.5 tesla magnet with T1-weighted (TR 500 ms, TE 15 ms) and a T2*-weighted (FISP 3D: TR 30 ms, TE 10 ms, flip angle 40 degrees). Postoperative MR follow-up showed an increase in signal intensity and diameter in T1-weighted images. This represents revascularisation of the transplant.

[MRI of the cervical spine using T1-weighted multislice FLASH sequences]. / MRT der Halswirbelsäule mit T1-gewichteten mehrschichtfähigen FLASH-Sequenzen.

A study has been carried out to evaluate contrast and image quality of cervical structures using multislice 2D-flash sequences with long repetition times (TR = 400 ms.) and short echo delay times (TE = 5.8 ms.). The examinations were carried out using ten normals with an MRI of 1.5 Tesla and flip angles of 10, 20, 30, 50, 70 and 90 degrees. The best contrast between intervertebral disc and surrounding tissue was obtained between 50 and 70 degrees, best contrast between compact bone and CSF with 10 degrees. In order to demonstrate degenerative changes of the cervical spine, it appears sensible to use a combination of these angles. The described sequences produce good images of the cervical structures with little image degradation. Compared to T1-weighted spin-echo sequences, the method has a number of significant advantages, such as variations in image contrast, higher maximal number of slices, contiguous imaging and less imaging time.

[MRT of brain metastases. (I) What is the place of screening with T2-weighted sequences?]. / MRT bei Hirnmetastasen. (I) Welchen Stellenwert hat das Screening mit T2-betonten Sequenzen?

Sensitivity and specificity of plain T2-WI and Gd-DTPA enhanced T1-WI were compared by evaluating MR exams of 30 patients with brain metastases. Large lesions with high signal on T2-WI always enhanced (43/43) when a structure (perifocal edema, tumor tissue, central necrosis) was found. Large lesions nearly always enhanced (53/55) even if no such structure was found. 65% of small unstructured white matter lesions with high signal on T2-WI, which are generally considered vascular, did not enhance. Surprisingly, 35% did enhance. Demonstration of blood brain barrier disturbance in these lesions suggested a metastatic origin. In 3 patients with multiple metastases, Gd-DTPA enhanced T1-WI disclosed more than 140 lesions not seen on T2-WI. All of them were located in or adjacent to grey matter. Our results indicate that enhanced T1-WI should be obtained even if T1-WI are normal or show only small white matter lesions.

[Optimization of gadolinium-DTPA dose: an inter-individual study of patients with intracranial tumors]. / Dosisoptimierung von Gadolinium-DTPA: Eine interindividuelle Studie an Patienten mit intrakraniellen Tumoren.

The diagnostic value of various doses of Gd-DTPA was compared intra-individually. Thirty-three patients with cerebral tumours were randomly allocated to three groups. Group 1 was given a dose of 0.025, group 2 a dose of 0.05 and group 3 a dose of 0.1 mmol GD-DTPA/kg body weight. Following administration of Gd-DTPA the average tumor/brain contrast in group 1 was -4.5%, in group 2 +8.4% and in group 3 +43.0%. Diagnostically useful tumour delineation was obtained in two out of 11 in group 1, in seven out of 11 in group 2 and in 10 out of 11 in group 3. A further increase in the dose to 0.2 mmol/kg body weight in group 3 resulted in a further increase in tumour/brain contrast of +62.5% and improved tumour delineation in one case. As a result of these findings a dose of 0.1 mmol Gd-DTPA/kg body weight is recommended for the routine investigation of intracranial tumours.