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P Reimer

Publications and source records attributed to P Reimer.

At least 73 records · Page 4Linked to original sources
PubMed1996

[Perfusion studies with paramagnetic contrast media and rapid pulse sequences in cerebrovascular diseases and brain tumors].

The combination of fast MR sequences and rapid i.v. injection of paramagnetic contrast media provides information on cerebral perfusion. MR-perfusion imaging primarily depicts the relative cerebral blood volume. The aim of this study was to test whether MR-perfusion imaging with a clinical MR scanner using a standard 2D-FLASH sequence provides clinically relevant information on patients with cerebrovascular diseases and brain tumors. Brain infarctions, lesions in cerebral microangiopathy and occlusions of the carotid artery with very poor collateralization showed definite differences in perfusion imaging compared with normal controls. However, our results show that acceleration of the imaging sequence and optimization of the contrast bolus and data processing are prerequisites for the clinical use of this method, which in principle may provide information on the absolute cerebral blood volume and even blood flow.

Adult↗
PubMed1996

[New MR contrast media in liver diagnosis. Initial clinical results with hepatobiliary Eovist (gadolinium-EOB-DTPA) and RES-specific Resovist (SH U 555 A)].

The purpose of this work is to describe our initial clinical experience (in 66 patients) with Resovist and Eovist, two new liver-specific MR contrast agents. We focus our report on safety aspects, dose finding, and optimization and technical parameters. Both contrast agents were well tolerated and improved the detectability of focal liver lesions. With Resovist, postcontrast MRI may be started as early as 10 min following injection. The dose of 8 mumol Fe/kg bodyweight was sufficient to achieve diagnostic tumor-liver contrast levels. Since Eovist can also be administered as a bolus, dynamic enhancement patterns may be studied for tumor characterization as well. Breath-hold T1-weighted FLASH images were superior to other T1-weighted techniques with and without fat saturation.

Contrast Media↗
PubMed1996

[High dosage Gd-DPTA-BMA (Gadodiamid) administration in diagnosis and therapeutic monitoring of malignant bone tumors].

PURPOSE: To evaluate the efficacy of high-dose Gd-DTPA-BMA (gadodiamide, Omniscan) as a contrast for magnetic resonance imaging of malignant bone tumors and the use of high-dose dynamic studies for predicting the response to pre-operative chemotherapy. MATERIALS AND METHODS: Examinations were performed in 22 patients with suspected malignant bone tumor on a 1.5 T system. In 8 cases a follow-up examination was done after preoperative chemotherapy. Static studies included Pd- and T2-weighted spin-echo sequences as well as T1-weighted spin-echo sequences, obtained pre- and post-contrast. Dynamic studies were performed using a FLASH 2D-gradient-echo sequence (TR 40 ms/TE 10 ms, 90 degrees flip angle) every 20 s after intravenous bolus injection of Gd-DTPA-BMA (0.3 mmol/kg body weight). MR images were evaluated qualitatively by visual assessment of conspicuity size, extraosseous delineation and structure of the lesion and quantitatively by measurement of the signal intensities and calculation of the relative increase in signal intensity. RESULTS: Qualitative image analysis showed best demonstration of the lesions on contrast-enhanced T1-weighted images. Comparison of T1-weighted pre- and postcontrast spin-echo sequences revealed significantly better assessment of tumor structure after administration of contrast media. After preoperative chemotherapy, all responders showed a markedly stronger reduction in relative increase in signal intensity in dynamic studies compared to nonresponders. CONCLUSION: Gd-DTPA-BMA is effective for magnetic resonance imaging of musculoskeletal lesions and improves assessment of the tumor structure. Dynamic studies may help to predict the response to preoperative chemotherapy.

Adolescent↗
PubMed1996

[Development and experimental use of receptor-specific MR contrast media].

The authors describe the feasibility of developing receptor-specific MR contrast agents for the improved detection of pathology and assessment of organ function. Receptor specificity of MR contrast agents can be achieved by binding of receptor-specific carriers to ligands. This concept leads towards a decrease in dose and thus in toxicity. Specific attachment to parenchymal cells improves tumor-organ contrast and therefore tumor detection. Specific uptake mechanisms also enable the assessment of organ function. Future design concepts of novel MR contrast agents may consider the desired uptake in specific cells or organs (ovaries, adrenal glands, lymph nodes etc.) with subsequent synthesis of appropriate carriers.

Animals↗
PubMed1996

[Primary non-Hodgkin's lymphoma of the skull in an 11-year-old girl. Follow-up and review of the literature].

The authors present a rare case of solitary non-Hodgkin lymphoma (NHL) in the skull of an 11-year-old girl. The clinical, radiological and histological findings as well as a review of the literature are included in this report. The morphological features of intra- and extracerebral tumor masses and the change in tumor extension due to chemotherapy and radiation therapy were evaluated with magnetic resonance imaging. Although rare, NHL should be considered in the differential diagnosis of skull tumors in children.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

[The value of 3-phase spiral CT and magnetic resonance tomography in preoperative diagnosis of pancreatic carcinoma].

UNLABELLED: The purpose of this study was to assess the role of spiral computed tomography (SCT) and magnetic resonance imaging (MRI) in the preoperative work-up of patients with pancreatic carcinoma, regarding local resectability and vascular involvement. METHODS AND MATERIALS: A total of 28 patients (19 men and 9 women; mean age 58 years) with known or highly suspected carcinoma of the pancreas were included in this study. All patients prospectively underwent MRI ( +/- gadolinium-DTPA ) and SCT (3-phase examination) as preoperative diagnostic imaging studies, and laparotomy was carried out within 7 days, irrespective of the MRI or SCT findings. SCT and MR studies were reviewed independently by two radiologists, without knowing the results of the surgical exploration. Standardized image analysis was correlated with findings at laparatomy. RESULTS: Laparotomy identified 10 patients to be suitable for surgical resection and 18 pancreatic carcinomas to be unresectable. In 17 of 18 non-resectable carcinomas MRI and SCT were able to obtain correct information about unresectability (sensitivity 94%), in 7 (MRI), resp. 8 (SCT) carcinomas were correctly considered to be resectable (sensitivity 70% of MRI and 80% for SCT). The presence of vascular involvement was depicted by SCT with a sensitivity of 82-100% and 62-100% by MRI. The specificity varied between 85-100% for SCT and 77-100% for MRI. CONCLUSION: Both MRI and SCT are good techniques for the preoperative work-up of pancreatic carcinomas in order to obtain a correct assessment of local resectability.

Adult↗
PubMed1996

Gadolinium-DTPA enhanced echoplanar MR imaging of the liver: preliminary observations.

This study describes our preliminary experience with dynamic gadopentetate dimeglumine enhanced echoplaner MR imaging (EPI) in fifteen patients with focal liver lesions. Lesion diagnosis was established by histology (n = 3) or typical imaging characteristics (exclusive of the EPI study) combined with clinical follow up (n = 12). Dynamic gadopentetate dimeglumine (0.1 mmol/kg) enhanced MR imaging was performed on a commercially available 1.5 T EPI equipped MR system using a single-excitation fat-suppressed inversion recovery pulse sequence. The choice of an IR sequence allowed nulling of the lesion signal by varying T1 prior to enhancement creating the optimal conditions for qualitative inspection of the enhancement profile. Intershot delay (defined as TR) ranged from 1-5s. Image analysis was performed qualitatively by two radiologists. Benign and malignant lesions displayed temporal enhancement profiles compatible with characteristic findings expected with conventional imaging modalities. Further refinements in our technique and expanded system capabilities will allow dynamic imaging of the entire liver with improved temporal resolution over conventional sequences.

Contrast Media↗
PubMed1996

Phase II clinical evaluation of Gd-EOB-DTPA: dose, safety aspects, and pulse sequence.

PURPOSE: To investigate the efficacy of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) in the detection of focal liver lesions with respect to dose, side effects, and pulse sequence. MATERIALS AND METHODS: A randomized double-blinded trial was performed in 33 patients with focal solid liver lesions. A bolus of Gd-EOB-DTPA, a liver-specific contrast agent, was intravenously administered at three different doses (12.5, 25, and 50 mumol per kilogram of body weight). Magnetic resonance imaging with different T1-weighted techniques was performed 20 and 45 minutes after administration of Gd-EOB-DTPA. Changes in liver signal intensity, lesion-liver contrast-to-noise ration (C/N), detectable liver lesions, side effects, and adverse events were evaluated. RESULTS: Gd-EOB-DTPA significantly (P < .05) increased liver signal intensity and lesion-liver C/N within the dose range tested. Lesion detection was improved 20 and 45 minutes after administration of Gd-EOB-DTPA. A dose of 12.5 mumol was sufficient for the detection of focal liver lesions, and the breath-hold, T1-weighted, fast low-angle shot pulse sequence was the most useful. No significant changes in vital signs, clinical laboratory test results, and urinalysis were observed. CONCLUSION: Gd-EOB-DTPA is an efficient, diagnostically useful, and safe contrast agent.

Contrast Media↗
PubMed1995

Application of a superparamagnetic iron oxide (Resovist) for MR imaging of human cerebral blood volume.

The authors describe the feasibility of dynamic MRI using a novel superparamagnetic iron oxide contrast agent. Resovist was injected as a bolus at doses of 4, 8, and 16 mumol Fe/kg bodyweight in three consented patients participating in a Phase 2 clinical multicenter trial for hepatic MRI. Dynamic images of the brain were obtained with a conventional FLASH sequence. Results were analyzed by evaluation of dynamic images, cerebral blood volume maps, and normalized signal intensity time curves. Resovist enabled rapid injections and a dose-dependent strong reduction in gray and white matter signal intensity. The small injection volume and good tolerability may enable Resovist to serve as a perfusion agent. Dedicated clinical trials are warranted to assess the potentials of Resovist for perfusion MRI and fMRI.

Blood Volume↗
PubMed1995

An organotypical in vitro model of the liver parenchyma for uptake studies of diagnostic MR receptor agents.

Testing of receptor-specific MR contrast agents targeted to the liver is hampered by a shortage of viable in vitro models with in vivo-like hepatocellular morphology. Coated pits are ultrastructural signs of an active receptor mediated endocytosis in hepatocytes. Expression of coated pits by matrix overlaid hepatocytes was studied by transmission electron microscopy. Binding of a rhodaminated asialoglycoprotein receptor agent (MION-ASF-rh) was assessed by fluorescence microscopy. Fluorescence of cells exposed to MION-ASF-rh with D(+)-galactose reduced fluorescent light emission to a level of 58% of MION-ASF-rh-induced fluorescence. After preincubation with the hepatotoxin CCl4 a dose-dependent decrease in fluorescent light emission resulted. Hepatocytes maintained a homogeneous cell surface expression, with microprojections, coated pits, and vesicles on both sinusoidal surfaces. Matrix overlaid primary hepatocytes constitute a viable, morphologically and functionally differentiated model. This model can be used to study receptor binding, uptake, and blockage of diagnostic magnetopharmaceuticals under controlled conditions.

Animals↗
PubMed1995

[The MRT of the orbit: the value of T1-weighted frequency-selective fat saturation at 1.0 and 1.5 tesla].

PURPOSE: To evaluate the diagnostic performance of fat suppression T1-weighted compared to conventional T1-weighted gadolinium-DTPA-(Gd-)enhanced spin echo sequences in orbital imaging. MATERIAL AND METHODS: 31 patients with pathologic conditions or clinically suspected pathology of the orbita were examined using conventional T1-weighted (TR 400-500 ms/TE 15 ms/AC 3) and fat suppression T1-weighted (TR 370-500 ms/TE 15 ms/AC 3) spin echo-sequences before and after i.v. injection of 0.1 mmol/kg Gd-DTPA. All images were evaluated by three radiologists experienced in MR imaging, concerning anatomical and pathological structures as well as artifacts. The images were graded on a scale of 1-5 (5 = excellent to 1 = poor). RESULTS: The evaluation of anatomic structures showed that the fat-suppression technique was superior to the conventional technique in respect of visualising the extraocular muscles (4.4 to 3.4, p < 0.05) and also with regard to the optic nerve (3.68 to 3.78). Pathological conditions of the orbit (optic glioma and neuritis, spread of local tumours to the orbit), however, were better visualised using the fat suppression technique (4.3 to 2.95, p < 0.05). CONCLUSION: Contrast-enhanced T1-weighted fat suppressed spin echo-sequences are useful in pathological conditions of the orbita. In optic neuritis they may be the only sequences to show the lesion.

Adipose Tissue↗
PubMed1995

Clinical results with Resovist: a phase 2 clinical trial.

PURPOSE: To investigate the superparamagnetic iron oxide (Resovist) designed for contrast material-enhanced magnetic resonance imaging of the liver. MATERIALS AND METHODS: A phase 2 trial was performed in 33 patients with no more than five known focal solid liver lesions. Resovist was administered intravenously at doses of 4, 8, and 16 mumol of iron per kilogram of body weight. Postcontrast 1.0-T imaging was started 30 minutes after injection. RESULTS: Resovist significantly (P < or = .05) decreased liver signal intensity and increased lesion-to-liver contrast-to-noise ratio (C/N) and the number of detectable liver lesions: fast spin-echo (SE) (echo time, 90 msec) precontrast C/N, 11.7 +/- 7.9 [standard deviation]; postcontrast [8-mumol Fe/Kg] C/N, 29.2 +/- 14.2). The dose of 8 mumol Fe/kg was sufficient for the detection of focal liver lesions, and T2-weighted fast SE with an echo time of 90 msec was the overall best pulse sequence. CONCLUSION: Resovist is a safe contrast agent, and a dose of 8 mumol Fe/kg is sufficient to enhance detection of focal liver lesions at T2-weighted fast SE MR imaging.

Contrast Media↗
PubMed1995

Morphological and functional characteristics of tumor-infiltrating lymphocytes from human colorectal cancers after stimulation with rIL-2.

Tumor-infiltrating lymphocytes (TILs) from colorectal cancers were separated from tumor cells by enzymatic and mechanical tissue disaggregation and discontinuous density gradients. Peripheral blood lymphocytes (PBLs) were isolated using the same procedure. The freshly separated TILs and PBLs were analyzed phenotypically by flow cytometry. The CD4+/CD8+ ratios of the freshly isolated TILs and PBLs were comparable (> 1 in both lymphocyte populations). CD25+, HLA-DR+ and CD56+ cells were significantly more frequent in the TIL than in the PBL population. However, the number of CD45RA+ cells was lower in the TILs as compared to PBLs, while CD29+ accumulated by about 90% in TILs. TILs and autologous PBLs were expanded in vitro with rIL-2. The mean rate of proliferation after 4 weeks was 642-fold in TIL cultures and 335-fold in PBLs. More than 90% of the rIL-2-expanded lymphocytes expressed CD2 and the great majority was CD29+. Stimulation with rIL-2 in vitro induced an outgrowth of CD56+ cells mainly in the TILs. Accordingly the expression of CD3+ and alpha/beta receptor in the TILs was low. Those cells which phenotypically represented lymphokine-activated killer cells displayed a lytic activity against the autologous tumor as well as against allogeneic K562 and Daudi targets. In accordance with the better proliferative response of TILs in long-term cultures with rIL-2, the lytic activity of TILs against autologous and allogeneic tumor targets was significantly higher as compared to PBLs.

Adult↗