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Biomedical subjects

R Felix

Publications and source records attributed to R Felix.

At least 487 records · Page 27Linked to original sources
PubMed1994

[Preoperative evaluation of drug resistant focal epilepsies with 123I-iomazenil SPECT. Comparison with vidio/EEG monitoring and postoperative results].

SPECT with the benzodiazepine receptor antagonist 123I-Iomazenil was performed in 33 patients with intractable partial seizures for pre-operative evaluation. The results combined with MRI and 99mTc-HMPAO-SPECT findings were compared with the video-assisted EEG monitoring ("gold standard") which localised the focus in 25 patients. 11 patients underwent surgical resection of the epileptogenic area and became seizure-free for a period up to 13 months. The Iomazenil SPECT had a significantly higher sensitivity compared to 99mTc-HMPAO in the visualization of an epileptogenic area and should be regularly used in the diagnostic of medically intractable partial seizures.

Adolescent↗
PubMed1994

[Current status of magnetic resonance tomography in diagnosis of the ankle joint--a critical evaluation].

Anatomical preparations of the ankle were examined by T1-weighted SE-sequences in three planes to identify normal topography. The current status of magnetic resonance imaging (MRI) was assessed and illustrated by image examples. Together with conventional radiography, MRI yields relevant information for therapy planning. This technique allows accurate staging of traumatic and degenerative involving the soft tissues of the joint, including tendons and ligaments. MRI clearly delineates joint fluid, osteochondral abnormalities, and is helpful in the diagnosis of inflammatory changes of the synovia and bone marrow. Furthermore, it is the modality of choice for evaluating tissue neoplasma. Its advantages are not only the detection of the process and definition of its extent, but also the determination of local soft-tissue infiltration.

Ankle Injuries↗
PubMed1994

[MR-angiography in diagnosis and follow-up of therapy: arteria lusoria].

Diagnostic and therapeutic procedures are presented in a 29-year-old female patient who suffered from severe dysphagia and rapid loss in weight. In the conventional X-ray examination and barium swallow an aberrant right subclavian artery was suspected. MR imaging (MRI) and MR angiography (MRA) were done to plan the surgical correction. Postoperative MRA documented exactly the complex topography after surgical correction and the flow pattern in the implanted Gore-Tex stretch graft prosthesis. Non-invasive MR angiography renders possible the concrete planning of complex corrections of thoracic vessels replacing invasive catheter angiography.

Adult↗
PubMed1994

[Lung activity in 201Tl myocardial scintigraphy: distribution and correlation with hemodynamic parameters].

UNLABELLED: The aim of this study was 1. to investigate whether the pulmonary activity in 201Tl myocardial scintigraphy can be accurately quantified from the anterior SPECT projection, 2. to determine the pattern of the intrapulmonary Tl distribution, and 3. to assess the influence of parameters of left ventricular function on the lung/heart ratio (LHR). Scintigraphic images of 85 patients were analysed. In 24 patients planar anterior imaging of the thorax was performed in addition to myocardial SPECT, in 41 patients radionuclide ventriculography was performed within 4 weeks after Tl scintigraphy. IN CONCLUSION: 1. pulmonary Tl-content can be quantitated from the anterior SPECT projection with sufficient accuracy, 2. a lower thallium activity was registered over the apical part of the lung as compared to the basal part, and 3. in the multiple regression analysis the left ventricular ejection fraction (LVEF) during exercise and heart rate during exercise (HRex) exhibited the strongest relation to LHR. After correction with regard to HRex the elevated LHR points to a pathological LVEF during exercise.

Exercise Test↗
PubMed1994

[123I-iomazenil- and 99mTc-HMPAO in the diagnosis of focal epilepsies: a comparison of untreated and treated patients].

The purpose of this study was to compare HMPAO- and IMZ-SPECT findings in treated and untreated patients with focal epilepsies. We examined 20 patients (untreated 13; treated 7). All patients had a normal CT and/or MRI scan. In all patients both whole-brain activity and regional count density (rcd) were evaluated by SPECT. Furthermore, the specific and non-specific binding of IMZ were calculated for each ROI and the results of both, treated and untreated patients were compared. Our data indicate that the normalized cerebral total binding of IMZ was significantly increased in all regions in the group of treated patients (p < 0.001). In contrast, no difference in the tracer binding was found with HMPAO-SPECT. We conclude that the difference in the IMZ-binding might be due either to exogenous or endogenous factors. In our study IMZ-SPECT had a higher sensitivity and a lower specificity in the detection of decreased rcd in areas with EEG findings that indicate an epileptogenic focus compared with HMPAO-SPECT.

Adolescent↗
PubMed1994

[MRT in degenerative diseases of the cervical spine].

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.

Cervical Vertebrae↗
PubMed1994

[Initial experiences with combined balloon angioplasty and rtPA thrombolysis in dialysis shunt failure].

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.

Adult↗
PubMed1994

[A dental CT study for preoperative assessment of maxillary atrophy].

According to a new technology in the planning of endo-osseous implantation, based on a new CT-software for evaluation of the bone structure of the jaws, anatomico-morphological changes after the loss of teeth are measured much more accurately than with conventional methods like the panoramic intraoral x-ray or conventional tomography. 30 mandibles and 22 maxillae of 36 patients were examined. Besides the topographic course of the mandibular canal and the location of the foramen mentale, the anatomic structures as the important aspects for planning endo-osseous implants are seen more accurately. It is now possible to recognise morphological changes with paraxial reconstructions in a very short time more clearly and precisely than with former techniques.

Adult↗
PubMed1994

[Quality criteria of digital subtraction angiography of the trunk of the body].

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.

Angiography, Digital Subtraction↗
PubMed1994

Differential diagnosis in variants or abnormalities of the hip on MRI.

In the differential diagnosis of unspecific hip pain MRI becomes increasingly important. In particular it is useful in the diagnosis of avascular necrosis, primary and secondary bone tumors, osteomyelitis and synovial processes. According to the higher frequence of MR examinations of the hip the number of nonpathological incidental findings is rising. 39 'pitfalls' and abnormalities were found on MRI of 152 patients with unspecific hip pain. Soft tissue penetrating cortical lesions of the femoral neck (herniation pit, n = 4), physiological changes of bone marrow, synovial proliferation (n = 6) of the hip joint capsule, epiphyseal scars of the femoral head (n = 12) and the transient osteoporosis (n = 12) are some of the morphological changes of the hip, which may cause difficulties and misinterpretations on MRI of the hip. Knowledge of their radiological characteristics on MRI is important, especially in cases of unspecific hip pain.

Adult↗
PubMed1993

[Lymph node metastases of the neck in unknown primary tumor: is there a differential imaging diagnosis?].

In 32 patients suffering from cervical lymph node metastases with an unknown primary tumour the pretherapeutic findings via sonography, CT and MR were compared and the post-therapy findings of tumour aftercare assessed. After an average follow-up period of 38 months the group of branchiogenic cervical cysts had no recurrence. In the group of 18 patients with more than one cervical lymph node metastasis without primary tumour, either the primary tumour or further lymph node metastases became manifest in 11 patients after an average follow-up period of 36 months. Imaging of the number of lymph node metastases and differentiation between malignant degenerated branchiogenic cysts and lymph node metastases without primary tumour is important for prognosis. A combination of findings from sonography, CT and MR enables performance of such differential diagnosis due to morphological aspects and aspects that are conditioned by the contrast medium.

Adult↗
PubMed1993

[Spiral CT: differential diagnosis of cervical swelling. Initial clinical results].

Spiral CT examinations were performed pretherapeutically in 27 patients in whom cervical lymph node enlargement had been suspected. The M/Q quotient known from sonography and MR can also be employed in CT by means of coronary and sagittal reconstruction. This improves CT differentiation between reactively changed and metastatically infiltrated lymph nodes in tumour patients. Hence, CT diagnosis can now make use of a highly sensitive and highly specific criterion for diagnosing lymph nodes. Another diagnostic improvement is that vascular infiltrations by lymph node metastases can now be visualised or excluded more readily. Spiral CT is also suitable in tumorous and non-tumorous processes for an accurate assessment of the extension of e.g. retropharyngeal abscesses or laryngoceles.

Abscess↗
PubMed1993

[Palpation and sonography in after-care of head-neck tumor patients: comparison of ultrasound tumor entity parameters].

The ranking of postoperative palpation and sonography is examined in respect of imaging of neck lymph node enlargement and neck lymph node metastases or lymphomas, using a prospective study involving 127 patients whose head and neck tumours had already undergone treatment. These patients had been subjected to tumour aftercare for an average period of 26 months. Sonography is well suited for detecting the presence of enlarged neck lymph nodes, the accuracy being 97.5%. In this study palpation was clearly less safely defined, the accuracy being only 85%. The following results were obtained in respect of the specific imaging of metastases: sensitivity of palpation (75%) is below that of sonography (M/Q ratio) (93%). In respect of specificity palpation also yielded poorer results than sonography (M/Q ratio 94%) because of the relatively high proportion of false positive palpations (17%). The reason for this is non-differentiation between reactively enlarged lymph nodes and lymph nodes metastases. The advantage of sonography vs palpation by using the M/Q ratio is therefore the accuracy of the findings (94% sonography, 81% palpation) and hence the clear reduction in false positive and false negative findings. Furthermore, sonography can image the exact relationship to surrounding tissue and especially the vessels. The drawback of sonography is that lymph nodes < 9 mm maximal diameter cannot be assessed with the safety and accuracy mentioned above. Sonomorphological criteria such as the central marrow reflex and a widened lymphatic node cortex enhance diagnostic safety of the sonographic expansion parameters to yield an assessment of tumour status.

Adult↗
PubMed1993

[MRT in cervical disk herniation: plain vs. contrast-enhanced images].

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.

Adult↗
PubMed1993

[CT contrast administration of iodine, gadolinium and ytterbium. In-vitro studies and animal experiments].

The absorption of the elements iodine, gadolinium and ytterbium in various dilutions was studied in relation to CT. Regression analysis and specific CT density measurements showed that absorption decreases from gadolinium to ytterbium and iodine. These results were confirmed by experiments using ten dogs. Boli of 0.5 molar gadolinium used for angio-CT without table movement showed the largest increase in density in the aorta and liver with an average of 190HU and 21HU respectively compared with iodine which gave 157HU and 12HU respectively. The animal experimental studies suggest that gadolinium and ytterbium are suitable contrast media for dynamic CT investigations.

Absorption↗