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Biomedical subjects

K Rosenkranz

Publications and source records attributed to K Rosenkranz.

9 recordsLinked to original sources
PubMed1992

Transcranial Doppler ultrasound in internal carotid artery and middle cerebral artery disease.

Using noninvasive transcranial Doppler sonography, we studied cerebral collateral patterns in 30 patients with stenosis and/or occlusion of the extracranial internal carotid artery (ICA). All patients with unilateral ICA stenosis less than or equal to 80% had normal transcranial Doppler findings. 80% of patients with unilateral and 50% of patients with bilateral ICA stenosis of more than 80% including those with occlusion showed a collateralization via the ipsilateral anterior and/or posterior cerebral artery. 20% of patients with unilateral and 50% of patients with bilateral ICA stenoses of more than 80% (including occlusion) had two or three collateral pathways, including the ophthalmic artery. Another ten patients with stenosis or spasm of the middle cerebral artery (MCA) showed increased flow velocities with turbulence in the narrow segment. In four patients with severe MCA disease with a systolic peak velocity of more than 200 cm/s, the Doppler waveform distal to the lesion was damped. Decreased regional cerebral blood flow (rCBF) measured by 99mTc-HMPAO-SPECT was found in two patients with severe MCA stenosis. Another patient with moderate MCA stenosis with a systolic peak velocity of 140 cm/s showed a normal cerebral perfusion pattern.

Adolescent↗
PubMed1992

Acetazolamide stimulation test in patients with unilateral internal carotid artery obstructions using transcranial Doppler and 99mTc-HM-PAO-Spect.

Fifteen patients with symptoms of cerebral ischaemia and angiographically confirmed unilateral stenoses or occlusions of the extracranial internal carotid artery (ICA) and 20 controls were studied by a 2 MHz transcranial Doppler (TCD) at rest and after stimulation with 1 g acetazolamide i.v., a cerebral vasodilator. In addition, the patients underwent 99mTc-HM-PAO-Spect measurement of regional cerebral blood flow (rCBF) at rest and after stimulation with 1 g acetazolamide. In 10 patients with ICA stenoses greater than 80% or occlusions, time-mean velocity (Vmean) increase and pulsatility index (PI) decrease in the postobstructive middle cerebral artery (MCA) as well as the increase of the ipsilateral rCBF were reduced in comparison with the contralateral side. The remaining 5 patients showed a normal Vmean increase and PI decrease in TCD.

Acetazolamide↗
PubMed1991

[Transcranial Doppler sonography in cerebrovascular diseases].

A review of our 1 1/2 years' experience with transcranial Doppler sonography (TCD) is given. In total, 619 TCD examinations were performed. Considering physiological variations of blood flow velocities in the intracranial arteries, TCD findings in stenoses and occlusions of the extracranial and intracranial brain-supplying arteries as well as in intracranial vasospasms were evaluated. In patients with leptomeningeal anastomoses demonstrated by TCD in the region of the peripheral middle cerebral artery, the regional cerebral blood flow was measured by 99mTc-HMPAO-SPECT. The value and limitations of TCD in cerebrovascular diseases and the indications to TCD examination of the intracranial arteries are discussed.

Carotid Artery Diseases↗
PubMed1991

Transcranial Doppler sonography: collateral pathways in internal carotid artery obstructions.

Fifty-four patients with stenoses and occlusions of the extracranial internal carotid artery (ICA) demonstrated by intravenous digital subtraction angiography (IVDSA) were studied by extracranial duplex and transcranial Doppler. Two hundred healthy volunteers served as control group. Intracranial collateralization was demonstrated in 32 patients with ICA stenoses greater than 80% and occlusions. Twelve patients with unilateral and 8 patients with bilateral ICA obstructions greater than 80% showed collateral supply via the anterior (ACA) and/or posterior cerebral artery (PCA). In 5 cases of unilateral ICA occlusion and in 7 patients with bilateral ICA stenoses greater than 80% and occlusions, the ophthalmic artery and ACA and/or PCA served as collateral vessels. Five patients with ICA occlusions showed leptomeningeal anastomoses in the region of the postocclusive middle cerebral artery (MCA). All 54 patients showed normal time-mean flow velocity in the post-obstructive MCA. In unilateral ICA stenoses greater than 80% and occlusions, the pulsatility index in the ipsilateral MCA was reduced in comparison with the contralateral side, indicating that this parameter is more sensitive to hemodynamic effects of ICA obstructions than time-mean velocity.

Angiography, Digital Subtraction↗
PubMed1990

[Transcranial Doppler sonography. Normal values and physiologic changes].

In 100 normal subjects mean flow velocity in the middle (MCA), anterior (ACA), and posterior (PCA) cerebral arteries and mean pulsatility index were examined by transcranial Doppler ultrasound. Age-dependent normal reference values were assessed. The measured parameters showed a large variation increasing with age. The highest flow velocities were found in the MCA, the lowest in the PCA. The highest mean side difference in flow velocity was observed in the ACA. An increase of pulsatility index and a decrease of flow velocities in all examined vessels were found with increasing age. The influence of ventilation and heart function on flow velocity and pulsatility index was demonstrated by the investigation of 10 normal subjects in different phases of ventilation and 1 patient with aortic valve insufficiency.

Adult↗