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Biomedical subjects

T Harder

Publications and source records attributed to T Harder.

At least 109 records · Page 6Linked to original sources
PubMed1988

[Multiple circular liver foci in latent porphyria cutanea tarda].

A 41-year-old patient with latent porphyria cutanea tarda is described; 8 years after mastectomy for carcinoma, sonography and CT showed multiple hepatic foci, which were at first interpreted as liver metastases. A liver biopsy was carried out during laparoscopy and u/v fluorescence and subsequent laboratory tests confirmed the diagnosis of porphyria cutanea tarda. Treatment with resochin produced almost complete resolution of the liver abnormalities within 9 months. Magnetic resonance tomography using proton-weighted SE sequences showed a few foci of high signal intensity.

Adult↗
PubMed1988

[Value of imaging procedures in the diagnosis and staging of bladder tumors].

A retrospective study of 161 patients with carcinomas of the bladder was carried out to assess the value of CT (247 examinations), transurethral sonography (32 examinations), and the early results of MRT. For TA-T3a staging, according to the TNM classification of the IUCC, transurethral sonography was particularly valuable. CT is useful for demonstrating transmural tumour growth (T3b) and organ invasion (T4), involvement of regional lymph nodes and distant metastases. Tumours in the roof of the bladder and at its base are well shown by MR tomography, using multiplanar sections.

Adult↗
PubMed1988

[MR tomography of non-tumor diseases of the brain and cervical cord].

118 examinations were carried out for non-tumorous diseases of the brain and cervical cord. The sensitivity of MRT was analysed and compared with 77 cases where CT had been performed or with sonography in children. MRT showed an abnormality in 80%, whereas CT or sonography lead to a diagnosis in only 43%. Because of the significantly higher sensitivity of MRT, this should be the primary means of examination for this type of case.

Acquired Immunodeficiency Syndrome↗
PubMed1988

[Digital subtraction angiography of acquired arteriovenous fistulas of the extremities].

The signs of arterio-venous fistulae in the extremities have been evaluated by DSA in 20 patients. Angiographic signs for the presence of A-V fistulae are the following findings: dilatation of the supplying artery, elongation of the supplying artery, solitary A-V aneurysm, angiomatous A-V aneurysm, reduced blood flow distal to the A-V fistula, early venous filling, development of a venous collateral circulation and demonstration of retrograde venous flow. Angiography remains the method of choice for demonstrating A-V fistulae.

Angiography↗
PubMed1988

[Artifact reduction via motion-compensating gradient shifting in MR tomography].

In 62 patients spinecho or gradientecho sequences compensated for motion were compared with corresponding non-compensated sequences. Compensation during MRT reduces those artifacts which are caused by regular motion. This is particularly effective during examination of the brain stem, spinal canal and the heart. The improved demonstration of the morphology of normal and diseases organs simplifies the analysis of the types of movement.

Brain↗
PubMed1988

[Arterial DSA using a trans-brachial 4-French catheter].

Arterial DSA by the trans-brachial route, using a 4-French-catheter has been performed in 33 patients. In these patients, trans-femoral DSA is contra-indicated because of previous surgery or markedly reduced femoral pulsation. Intravenous DSA was not expected to provide diagnostically adequate information in these patients, in view of the well known method limitations of this method. In 20 patients, the abdominal aorta, pelvis and lower limb arteries were examined, in 14 only the leg arteries, in ten patients the arteries in the neck and in three patients the thoracic and abdominal aorta. Trans-brachial DSA provided good demonstration of the vessels in all cases.

Angiography↗
PubMed1988

[Use of a homomorphic filter in combination with surface coils in MR tomography].

A new method for correcting the signal intensity from surface coil (homomorphic filters) was evaluated in 40 examinations. With this filter it is possible to compensate for signal loss when using surface coils for deep tissues and to avoid excessive signals from the surface. The method does not, however, provide any additional information. Properly used, there were no false positive findings, nor was there any loss of abnormal findings. The use of homomorphic filters is therefore safe and sensible.

Filtration↗
PubMed1988

[MR tomography of hepatic hemangioma].

MR tomography of the liver using 1.5 T has been carried out in 63 patients with focal lesions in order to demonstrate haemangiomas and to differentiate these from primary and secondary malignant liver tumours. This differentiation was possible in all patients, using conventional spin echo and inversion recovery sequences in combination with sonography. Accuracy was much less good when using gradient echo sequences. With sufficiently large tumours, measurement of relaxation time made possible diagnosis of all the 22 haemangiomas.

Adult↗
PubMed1988

[Functionally significant changes in the shape of the right ventricle in digital subtraction angiocardiography].

Experiences in i.v. digital subtraction angiocardiography (DSAC) including so-called parametric imaging for morphological delineation of the right ventricle are illustrated. 32 patients with different anatomical and haemodynamic disturbances of the right ventricle were subjected to these examinations. Special emphasis is placed on pulmonary stenosis, particularly on its infundibular manifestations. For visualisation of muscular or fibrous bulging or other changes of the outflow tract of the right ventricle, analysis of the amplitudes is very suitable to produce cumulative pictures of ventricular wall motion during a cardiac cycle. Obstructive wall alterations within the infundibular part become visible even if they occur only during certain phases of the myocardial action, usually in late systole than otherwise.

Adolescent↗
PubMed1988

[Radiological diagnosis and therapy of postoperative abdominal lymphoceles].

Eighty-one patients with postoperative abdominal lymphoceles were examined by CT and ultrasound. Both methods provide accurate information regarding localisation and extent of the lymphocele. In 51 patients conservative treatment under sonographic or CT observation was carried out. In seven patients, irradiation lead to complete regression. In 21 patients, interventional radiological therapy was carried out with simultaneous irradiation in seven cases. In five patients surgery was necessary. Asymptomatic lymphoceles should be treated conservatively and only after the appearance of clinical symptoms should interventional radiological or surgical measures be carried out.

Abdomen↗
PubMed1988

[Phlebography of the upper extremity--examination technic, indications and results].

Three radiological methods of examination can be used in phlebography of the upper extremity: screening (fluoroscopy) combined with on-target x-ray film examination; sheet film angiography; digital subtraction phlebography (DSP). Phlebography of the veins of the forearm performed preoperatively for selecting suitable veins for a dialysis shunt, should be done by screening with on-target x-ray film takes in several planes. DSP should be given preference if there is suspicion of thrombosis of the shoulder veins and the superior vena cava.

Arm↗
PubMed1987

Radiological diagnosis of the thoracic aortic aneurysm.

Indications and the diagnostic value of radiological investigation methods in thoracic aortoaneurysm are reported. The suspected diagnosis can already be made on the basis of conventional x-ray examination of the thorax. Computer tomography (CT) with i.v. administration of contrast medium allows unequivocal identification of a mediastinal space occupation as an aneurysm. However, preoperative angiography is indispensable in many cases for appraisal of the vessel origins. Depending on the condition to be investigated, digital subtraction angiography (DSA) which is carried out with i.v. or i.a. injection of contrast medium has replaced conventional angiography here. Nuclear magnetic resonance tomography has only minor importance so far despite the good imaging of the aorta.

Angiography↗
PubMed1987

[Parametric visualization of cerebral perfusion by intravenous digital angiography].

Intravenous digital subtraction angiography is often used for evaluation of the extracranial and major intracranial vessels. The information obtained by this examination concerning cerebral perfusion is usually judged visually. In 50 patients a time-density curve at a specific point was analysed using 128 X 128 matrix. The level of grey scale at the moment of arrival of the bolus permits estimation of the haemodynamics of the intracranial vessels and provides a simple demonstration of differences of perfusion.

Adult↗
PubMed1987

[Digital subtraction angiography and large-film angiography of the pelvic and leg arteries].

The diagnostic information and image quality of 1153 DSA studies of pelvic and lower limb arteries and of 104 conventional large film angiograms have been analysed. Using intra-arterial contrast, all large film angiograms and all DSA studies of the iliac, femoral, popliteal and upper calf arteries were satisfactory. For demonstrating the distal calf vessels and vessels in the foot, intra-arterial DSA was superior to large film angiography. Using intravenous DSA, 98% of the iliac, femoral and popliteal arteries were adequately demonstrated, although image quality was reduced.

Angiography↗
PubMed1987

[Computed tomography and angiography in aortic dissection].

The authors report on 32 patients with dissecting aneurysm examined via computed tomography, 21 of whom were also additionally examined by means of angiography. Whereas CT with contrast medium bolus resulted in a diagnosis in dissecting aneurysm in all the cases, aortography failed in 2 patients because of a thrombosed dissection. Aortography offers clear advantages over CT, besides better spatial representation, in respect of clarification as to which aortic branches are involved, especially in the region of the aortic arch. On the other hand, the advantages of CT are lower invasiveness, high sensibility and the possibility of including concomitant complications when establishing the diagnosis.

Aortic Dissection↗
PubMed1987

[A procedure for taking into account scattered radiation and scattered light in the densitometric determination of intravascular iodine content].

Scattered light and scattered radiation are two significant sources of error during video densitometry and lead to local under-estimation of iodine concentration. A procedure is described using digital subtraction angiography which largely eliminates both factors. The measured intravascular iodine concentration is close to the true value throughout the entire intensifier field and quantitative evaluation is independent of local factors. The reduction of the artifacts improves diagnostic certainty during visual evaluation also.

Absorptiometry, Photon↗