[Visualizing muscular phosphorus metabolites in peripheral arterial occlusive disease].
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Adenosine Triphosphate↗
Biomedical subjects
F Gückel
Publications and source records attributed to F Gückel.
Two-exponential analysis of spin-spin proton relaxation times in MR imaging using surface coils.
Proton relaxation time measurements were performed on a standard whole body MR imager operating at 1.5 T using a conventional surface coil of the manufacturer. A combined CP/CPMG multiecho, multislice sequence was used for the T1 and T2 relaxation time measurements. Two repetition times of 2000 ms (30 echoes) and 600 ms (2 echoes) with 180 degrees-pulse intervals of 2 tau = 22 ms were interleaved in this sequence. A two-exponential T2 analysis of each pixel of the spin-echo images was computed in a case of an acoustic neurinoma. The two-exponential images show a "short" component (T2S) due to white and gray matter and a "long" component (T2S) due to the cerebrospinal fluid. In the fatty tissue two components with T2S = 35 +/- 3 ms and T2L = 164 +/- 7 ms were measured. Comparing with Gd-DTPA imaging the relaxation time images show a clear differentiation of vital tumor tissue and cerebrospinal fluid.
Equipment Design↗
Systemic bone marrow disorders: characterization with proton chemical shift imaging.
In a prospective clinical study, 26 patients (22 with malignant lymphoma and 4 with myelofibrosis) and 9 healthy volunteers were examined by conventional magnetic resonance and proton chemical shift imaging (CSI; modified Dixon method). On the basis of the CSI data, a quantitative evaluation of the relative fat and water signal fractions in regions of interest of the femur, pelvis, and spine was performed. In 16 of 17 patients with biopsy-proven bone marrow disorders, CSI revealed a significant reduction in the fat fraction of the bone marrow relative to that of normal volunteers. The visual assessment could detect only 14 of the 17 pathological cases.
Bone Marrow↗
Proton chemical shift imaging of bone marrow for monitoring therapy in leukemia.
In three patients with different forms of leukemia, follow-up examinations before, during, and after chemotherapy and bone marrow transplantation were performed by proton chemical shift imaging (1H-CSI). The relative fat and water fractions were computed in representative regions of the marrow in the femur, pelvis, and lumbar spine. On serial examinations the fat fractions increased over time, in agreement with the responses to therapy proven by bone marrow biopsies from the iliac crest. These preliminary results suggest a role for magnetic resonance and CSI in the monitoring of therapy in leukemia and systemic neoplastic diseases.
Acute Disease↗
Assessment of cerebral blood volume with dynamic susceptibility contrast enhanced gradient-echo imaging.
OBJECTIVE: Dynamic susceptibility contrast (DSC) enhanced MRI was used to study relative cerebral blood volume (rCBV). MATERIALS AND METHODS: We examined 15 healthy subjects and 47 patients with vascular stenosis or occlusion, with brain infarctions, and with cerebral neoplasms. During bolus injection of Gd-diethylenetriamine pentaacetic acid, a series of rapid T2*-weighted fast low angle shot two-dimensional images were recorded from the same slice. From these images, changes in signal intensity during bolus passage were computed pixel-by-pixel and converted into contrast agent concentration curves. Applying the principles of indicator dilution theory, images of rCBV were calculated. RESULTS AND CONCLUSION: Regions of infarctions show almost zero rCBV. In patients with high-grade vascular stenosis or occlusion a bolus delay in comparison to the unaffected side and an increased mean transit time can be observed. Some of the affected areas show an increased rCBV, which is a well-known physiological mechanism that takes place to compensate for the reduced cerebral blood pressure. In brain tumors, rCBV imaging reveals focal or homogeneous areas of increased blood volume. This can even be observed in low-grade astrocytomas with unaffected blood-brain barrier. In CBV imaging, the effects of radiotherapy on tumor tissue can be monitored as a significant decrease of rCBV in tumor tissue after therapy.
Adult↗