Biomedical subjects

M Laniado

Publications and source records attributed to M Laniado.

At least 73 records · Page 4Linked to original sources

PubMed1989

[Gadolinium-DTPA as an oral contrast medium in magnetic resonance tomography].

80 patients with tumorous or inflammatory abdominal diseases were investigated with the paramagnetic MRT contrast medium Gadolinium-DTPA (Gd-DTPA, 1 mM, 15 g/l mannitol, 6-16 ml per kg body weight) at 0.5 Tesla with T1-, proton density and T2-weighted SE- and gradient-echo sequences. 53 patients were investigated also before the contrast medium was given. Gd-DTPA showed hyperintense labelling of the intestinal loops that was detectable with all excitation sequences and was constant over all phases of the passage. In 35 of the 53 patients investigated before and after application of Gd-DTPA lesions were better imaged while diagnostic improvements, especially for smaller lesions, were achieved in 5 of 80 patients. One third of the patients reported slight meteorism and diarrhoea after the mannitol-containing suspension.

Administration, Oral↗

PubMed1989

[A new multislice gradient echo sequence for magnetic resonance tomography of the liver].

A multislice gradient echo sequence was developed for screening the liver and examined in studies on probands. This sequence is characterized by pronounced T1-weighting and low susceptibility to artifacts as well as a good contrast-to-noise ratio. Examination of the probands yielded suitable parameters for the repetition time, the delay echo, the excitation pulse angle and the number of data acquisitions. The optimized sequence yields, at a repetition time of 306 msec and an echo delay of 12 msec, 18 adjacent slices. With these measurement parameters an excitation pulse angle of 90 degrees was found to be adequate. Four data acquisitions (5.4 minutes measurement time) resulted in an effective reduction of motion artifacts. Compared with the T1-weighted spin echo sequences, the entire liver can be measured in half the time when using the multislice gradient echo sequence.

Humans↗

PubMed1988

[A multislice gradient-echo sequence for contrast medium-enhanced MR diagnosis of intracranial tumors].

A multislice gradient echo sequence (FLASH) was compared with a conventional spin-echo (SE) technique with regard to its value for contrast enhanced MR diagnosis. In 28 patients with cerebral tumours, SE images (SE 400/30; four images/3.4 minutes) and FLASH images (FLASH 315/14; 15 images/1.4 minutes) were obtained before and after gadolinium DTPA. After gadolinium-DTPA results were comparable for both techniques with respect to contrast enhancement, tumor contrast and delineation. Because of the higher efficiency of the FLASH 315/14 technique, this sequence is the method of choice for contrast enhanced cerebral MR imaging.

Adult↗

PubMed1988

[Oral contrast media for magnetic resonance tomography of the abdomen. III. Initial patient research with gadolinium-DTPA].

32 patients with abdominal tumours or inflammatory abdominal diseases were examined by MRI (0.5 T) prior to and after oral administration of gadolinium-DTPA (Gd-DTPA). T1- and T2-weighted sequences were employed. 10 ml/kg body weight of a Gd-DTPA formulation were administered (1.0 mmol/l, 15 g mannitol/l). Gd-DTPA provided markedly hyperintensive opacification of the gastrointestinal tract. In 19 of 32 studies Gd-DTPA-enhanced scans showed improved delineation of abdominal pathologies. In most cases Gd-DTPA-enhanced T1-weighted multislice gradient echo images provided the most useful diagnostic result. Meteorism and diarrhea were recorded in 13 patients.

Abdomen↗

PubMed1988

MR imaging of the gastrointestinal tract: value of Gd-DTPA.

To determine the value of gadolinium-DTPA (Gd-DTPA) as an MR contrast material for the gastrointestinal tract, we obtained T1-, T2-, and proton-density-weighted MR scans of the abdomen in 20 volunteers before and after oral administration of the compound (10 ml/kg of a 0.5- or 1.0-mM solution). Gd-DTPA was given either alone or with mannitol (15 or 30 g/l). Opacification of the small bowel after the administration of 1.0 mM Gd-DTPA was superior to that achieved after administration of the 0.5-mM solution. In the absence of Gd-DTPA, the pancreas could be delineated partly in 11 cases. After administration of Gd-DTPA, the pancreas could be well differentiated from stomach and duodenum in 16 of 20 cases. In the absence of mannitol, two of the five subjects had homogeneous opacification of the entire small bowel. When Gd-DTPA was given with either 15 or 30 g mannitol/l, homogeneous opacification of the entire small bowel was obtained in nine of 10 volunteers. Diarrhea not discomforting to the volunteers was noted in four of 20 cases. No abnormal blood tests were recorded after administration of Gd-DTPA. The results suggest that oral administration of Gd-DTPA (1.0 mM) given with mannitol (15 g/l) is effective as an MR contrast agent for the gastrointestinal tract. The formulation was found to be safe in a small series of 20 volunteers.

Adult↗

PubMed1987

[Characteristics of intracranial meningioma imaged by magnetic resonance tomography].

Twenty-three patients with intra cranial meningiomas were examined by means of magnetic resonance tomography (MRT). In 13 patients the paramagnetic contrast medium gadolinium DTPA was used. Meningiomas show only slight changes in signal intensity compared with brain in the spin-echo mode, the greatest contrast being found on photon density images (TR 1600 ms, TE 35 ms). In T1 images, more than 50% patients showed a low signal margin between tumour and brain, Hyperostosis of the calvarium is easily recognised, but MRT is unreliable for showing tumour calcification. After intravenous injection of gadolinium DTPA, there was marked homogeneous uptake in the meningiomas. These signs are useful for the diagnosis of a meningioma by MRT.

Adult↗

PubMed1987

[Rapid nuclear magnetic resonance tomography. Initial results of studies using the new gradient echo sequence].

In 60 patients with intracerebral lesions, examined by MRI, a new gradient-echo sequence was employed. This imaging technique uses excitation pulse angles smaller than 90 degrees and echoes are produced by an inversion of the read gradient. Since no 180 degrees pulse between successive excitations is necessary, very short repetition times can be used. Depending on matrix-size and signal averaging, MR imaging time can be reduced to approximately 5 to 40 seconds for single slice scan. For comparison, conventional T1- and T2-weighted spin-echo images were performed. Diagnostic results of the T1-weighted fast gradient-echo images corresponded with T1-weighted spin-echo images in 30% of cases. Diagnostic information was lower in 40% of cases. In the remainder of cases (30%) lesions were not detected with the gradient-echo technique. This especially applied to multiple sclerosis, infarctions and low-grade gliomas. Due to image artefacts and low contrast, visualization of small pathologic lesions was limited. Significant improvement of tumor visualization on gradient-echo scans was observed after injection of Gd-DTPA (0.1 mmol/kg).

Brain Diseases↗

PubMed1987

[Oral contrast media for magnetic resonance tomography of the abdomen. 1. Comparative animal studies of positive and negative contrast media].

Beagle dogs were investigated by MRI (Siemens Magnetom, 0.35 T) after oral administration of aqueous solutions of Gd-DTPA (n = 4), ferric ammonium citrate (n = 1), and magnetite dextran (n = 2). High signal intensity of the GI-tract versus adjacent structures was obtained with Gd-DTPA and ferric ammonium citrate. Magnetite showed negative contrast versus adjacent structures. However, magnetite displayed lower contrast relative to liver, muscle and gut wall compared to Gd-DTPA and ferric ammonium citrate. In relatively T2-weighted sequences labeling of poorly filled bowel loops was significantly better with Gd-DTPA and ferric ammonium citrate. For GI-tract contrast enhancement we conclude that positive contrast media are of higher diagnostic value compared to negative contrast agents.

Abdomen↗

PubMed1987

[Oral contrast medium for magnetic resonance tomography of the abdomen. II. Phase I clinical testing of gadolinium-DTPA].

20 male volunteers were examined by MRI to determine safety and efficacy of Gd-DTPA formulations for gastrointestinal (GI)-tract contrast enhancement. Prior to and after administration of contrast spin-echo images were obtained. Volunteers were studied after administration of 10 ml contrast medium/kg (1.0 mmol Gd-DTPA/l vs. 0.5 mmol Gd-DTPA/l, no mannitol vs. 15 g mannitol/l vs. 30 g mannitol/l). Gd-DTPA provided high signal intensity in the GI tract. Contrast medium in gastric lumen and duodenum permitted improved delineation of pancreatic head and ventral outline in 16 of 20 subjects. No clinically relevant side effects were seen.

Abdomen↗

PubMed1986

[Magnetic resonance tomography of intracranial tumors: use of contrast media versus T2-weighted tomograms].

Nuclear magnetic resonance tomography was performed on 38 patients with intracranial tumours, before and after the administration of contrast, using a 0.35 T Magnetom. The MR examinations included various plain spin-echo sequences (SE 400/35, 800/35, 1600/35, 1600/70, 1600/105, 1600/120) as well as examinations after the iv-administration of gadolinium-DTPA (SE 800/35). On all occasions, the abnormalities were visible without contrast. Differentiation of tumour and its surroundings was possible in 19 out of 38 cases without contrast. Delineation of expansively growing tumours (eg. meningiomas) was possible in twelve out of 14 cases, but in only seven out of 24 cases with infiltrating tumours (eg. glioblastomas). On the other hand, clear differentiation between tumour and adjacent edema and normal brain, respectively, was possible in 35 out of 38 cases after Gadolinium-DTPA.

Adult↗

PubMed1986

Spin echo and inversion recovery sequences for gadolinium-DTPA enhanced magnetic resonance imaging of intracranial tumors.

In 36 patients with intracranial tumors, gadolinium (Gd)-DTPA-enhanced SE 400/35, SE 800/35 and IR 1500/400/35 sequences were intraindividually compared. Contrast enhancement usually was shown to better advantage with the IR sequence. Post-contrast SI of tumor tissue was isointense with white matter on IR images in many cases whereas SE sequences displayed enhancing tumor with high contrast versus brain. Post-contrast tumor delineation, therefore, was better with the SE sequences especially in white matter lesions without perifocal edema. The SE 400/35 sequence which allows for contrast-enhanced MRI within a relatively short time is suggested for Gd-DTPA studies of brain tumors.

Brain Neoplasms↗

PubMed1986

Magnetic resonance imaging of intracranial tumors using gadolinium-DTPA. Initial experience with fast imaging.

One hundred and fifty gadolinium(Gd)-DTPA studies in patients with intracranial tumors were performed. In meningiomas (n = 37) Gd-DTPA is useful to delineate isointense tumors. In acoustic neuromas (n = 16) Gd-DTPA helps to identify intracanalicular tumor tissue. In pituitary adenomas (n = 16) para- or suprasellar tumor extension can be better appreciated after Gd-DTPA injection. In glioblastomas (n = 23) Gd-DTPA provides data on differential diagnosis through the characteristic shape of enhancement. In a variety of tumor types the high contrast between enhancing tumor tissue and adjacent structures facilitates therapy planning. Fast imaging sequences now allow for dynamic Gd-DTPA studies. The time-course of enhancement may increase specificity of magnetic resonance imaging.

Brain Neoplasms↗

PubMed1986

Some aspects of the use of contrast agents in magnetic resonance imaging.

The parameters for signal intensity in magnetic resonance imaging (MRI) are classified and shortly described. Proton density, T1 and T2 are discussed as tissue parameters to be influenced in different ways by different types of contrast agents. Conclusions for the development of contrast agents for MRI are drawn. The influence of the concentration of paramagnetic substances on signal intensity is shortly described. The good tolerance of Gd-DTPA as a contrast agent for MRI is reported. Its favorable use is shown in three examples of brain tumors.

Adult↗

PubMed1985

Application of contrast agents in CT and MRI (NMR): their potential in imaging of brain tumors.

21 patients with clinical and CT diagnoses of intracranial tumor were studied by MRI (NMR) prior to and after administration of intravenous Gadolinium-DTPA. Resultant MRI images were compared with corresponding CT sections with respect to lesion detection, contrast enhancement, tumor delineation and visualization of perifocal edema. All intracranial lesions shown on CT were identified on MRI. Contrast enhancement in MRI images was achieved in 19 out of 21 patients, as it was also with CT. In these cases improved differentiation between tumor, perifocal edema and adjacent brain structures were obtained. In most cases sufficient visualization of perifocal edema in MRI required T2 weighted images (SE 1600/70) in addition to spin echo scans routinely performed prior to and after contrast medium (SE 400/30 or 800/30). No side effects were encountered following administration of Gadolinium-DTPA. The good tolerance and the efficacy justifies the use of Gadolinium-DTPA for contrast enhanced MRI imaging.

Adult↗

PubMed1985

Initial clinical evaluation of gadolinium DTPA for contrast-enhanced magnetic resonance imaging.

Gadolinium DTPA was evaluated as an intravenous contrast agent for magnetic resonance imaging in 15 patients with primary or secondary intracranial neoplastic disease. T1 and T2 weighted images were obtained prior to contrast administration. T1 weighted spin echo 35/800 (TE/TR) images were utilized to detect enhancement. The increase in signal intensity observed, identifying areas of breakdown of the blood-brain barrier (BBB), was similar in magnitude to the contrast enhancement observed on CT. This permitted differentiation of neoplastic tissue from surrounding cerebral edema on MRI. Direct visualization of otherwise "isomagnetic" lesions was also demonstrated. The use of intravenous contrast media should significantly extend the diagnostic potential and specificity of magnetic resonance imaging.

Brain Edema↗

PubMed1985

[Effect of the contrast medium on the gray shading in magnetic resonance tomography].

Contrast media can significantly improve the diagnostic value of MR tomography. The basis of using contrast material for MR depends on totally different physical principles from those employed in conventional radiological diagnosis. The physical factors underlying the use of these contrast media are described, various suitable substances are discussed, and experience so far gained with some contrast agents is outlined.

Contrast Media↗

PubMed1985

[Contrast media in magnetic resonance tomography. A review. 1. Physicochemical and pharmacological bases of MR contrast media using gadolinium-DTPA as an example].

The principles underlying contrast media for MR tomography are totally different from those for conventional contrast media. Substances suitable for MR tomography are paramagnetic complexes which alter the relaxation times of the tissues. Signal intensity on the MR images are influenced correspondingly. The mode of action of MR contrast media is explained. Gadolinium-DTPA, the first MR contrast medium in clinical use by means of intravenous injection, is described. Its tolerance has been investigated by animal experiments and its effectiveness as an contrast agent has been studied in normal individuals. In the second part of the paper, early results from the use of gadolinium DTPA are given. The additional information which can be obtained by using MR contrast media is discussed.

Animals↗

PubMed1985

[Contrast media in magnetic resonance tomography. A review. 2. Biological basis, research technic and clinical application of gadolinium-DTPA in the diagnosis of intracranial tumors].

The early results of the use of the MR specific contrast medium gadolinium-DTPA in 40 patients with intracranial tumours are reported. Optimal pulse sequences, contrast dose and timing are discussed. The relationship between the blood-brain barrier and contrast distribution within tumour tissue is elaborated. The clinical significance of the application of contrast agents in the diagnosis of brain tumours is evaluated.

Adult↗