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Biomedical subjects

M Laniado

Publications and source records attributed to M Laniado.

At least 55 records · Page 3Linked to original sources
PubMed1994

[The MR tomography of focal liver lesions with the superparamagnetic contrast agent AMI-25 at 1.5 tesla].

Superparamagnetic iron oxide particles (AMI-25) were evaluated as a liver contrast agent in high-field MR imaging (1.5 T). 16 patients with up to 5 presumed focal liver lesions (liver metastases n = 8, HCC n = 5, Klatskin tumours n = 2, FNH n = 1) received 15 mumol Fe/kg BW intravenously and were examined via standard T1- and T2-weighted spin-echo sequences. Quantitative image analysis showed a post-contrast increase of the contrast-to-noise ratio (C/N) from 1.6 to 7.4 on SE 2,500/15 images (p < .05). However, C/N was in the same range on plain SE 2,500/90 scans. Blind evaluation by two independent readers revealed that AMI-25-enhanced images did not provide a significantly increased number of lesions. Two patients reported minor, self-limited side-effects (flush, back pain). We conclude that in contrast to reports at mid-field MR imagers, the use of AMI-25 at 1.5 T does not significantly improve the detection of focal liver lesions on conventional SE images.

Adult↗
PubMed1994

[A comparison of positive and negative enteral contrast media for the magnetic resonance tomography of the abdomen].

Following oral administration of a buffered gadopentetate-dimeglumine solution (Magnevist enteral, 1 mmol/l, 6-17 ml/kg) T1-, proton-density- and T2-weighted spin-echo images of abdominal and retroperitoneal lesions were acquired (0.5 T). Gadopentetate is a signal-enhancing, positive MR contrast agent, intraluminal air served as a model of a signal-free, negative agent. In 21 patients contrast/noise ratios of gadopentetate and air versus lesions and fat were compared quantitatively (t-test). In T1- and T2-weighted images contrast/noise ratios of gadopentetate versus lesions were significantly higher than those of air. In proton-density images there was no significant difference. In T1- and proton-density images contrast/noise ratios of air versus abdominal fat were significantly higher than those of gadopentetate, in T2-weighted images gadopentetate had a significantly higher contrast/noise ratio than air. Signal-enhancing positive contrast agents seem advantageous over signal-free negative enteral MR contrast agents.

Abdomen↗
PubMed1993

[Magnetic resonance imaging in perianal Crohn's disease].

Magnetic resonance imaging (MRI) was undertaken in a prospective study of 34 consecutive patients (21 women, 13 men; median age 31 [18-53] years) suspected of having active perianal Crohn's disease. The results of the investigation were compared with those obtained by independent observers on proctological and intraoperative examination (n = 31). A total of 58 fistulas and 21 abscesses were noted intraoperatively, 47 fistulas and all 21 abscesses by MRI, and 40 fistulas and 13 abscesses proctologically. The proctological examination proved to be more sensitive in demonstrating short subcutaneous or anovaginal fistulas (three of four subcutaneous and two of five anovaginal fistulas were not shown by MRI). Intersphincteric, ischiorectal and supralevator involvement was shown better by MRI. These results indicate that in perianal Crohn's disease MRI is a useful addition to proctological examination.

Abscess↗
PubMed1993

The double-line sign of osteonecrosis: evaluation on chemical shift MR images.

The MR appearance of osteonecrosis was assessed on selective fat and water images to further evaluate the features of the double-line sign of osteonecrosis. Conventional T1- and T2-weighted spin-echo and frequency selective chemical shift images of eight patients with avascular necrosis of the femoral head and three patients with bone infarcts were retrospectively reviewed. Eight of 11 patients showed a double-line sign on T2-weighted spin-echo images. In these cases correlation with selective water images revealed that a chemical shift artifact contributed to the appearance and location of the hyperintense line. The double-line sign was not seen in three patients with radiologically and clinically proven osteonecrosis. It is concluded that chemical shift imaging improves our understanding of the nature of the double-line sign.

Adult↗
PubMed1993

[Special MR methods for primary bone tumors: I. Chemical shift selective imaging].

The value of selective imaging of fat and water compared with proton density, T1- and T2- weighted MR sequences was studied in the course of 32 examinations on 22 primary bone tumours in various parts of the body. Fat selective images showed practically signal free areas for osteogenic tumours which could be distinguished from surrounding fat containing soft tissues. Water selective images improved definition of the tumour margin from oedema in the bone marrow. Chemical shift artefacts are avoided by these methods and therefore fat and water selective images provide better spatial resolution for identical pixel sizes.

Adolescent↗
PubMed1993

[Special MR methods for primary bone tumors: II. Volume selective 1H-spectroscopy].

The method of localised 1H MR spectroscopy was used in 19 examinations in 9 patients with primary bone tumours in order to obtain spectral signals and to determine whether these are specific for tumour classification. The spectra were obtained by a double spin echo method and the tumour tissue showed very high water content and only minor lipid and proton signals which showed J-coupling characteristics. The latter are not found in normal bone marrow and are probably due to products of tumour metabolism. The resolution of the spectra within a 13 mm or 20 mm tissue cube depends largely on the structural homogeneity of the tumour. The signal patterns in the spectra were not specific to histological tumour types.

Adolescent↗
PubMed1993

Triple-dose versus standard-dose gadopentetate dimeglumine: a randomized study in 199 patients.

To investigate the safety, patient tolerance, and efficacy with 0.3 mmol/kg gadopentetate dimeglumine in magnetic resonance (MR) imaging of the central nervous system (CNS), a phase 3 trial was conducted in 199 patients with suspected CNS lesions. Patients received either 0.1 or 0.3 mmol/kg gadopentate dimeglumine (injection time, 15 seconds and 45 seconds, respectively). T1- and T2-weighted spin-echo sequences were performed at either 0.5 T or 1.5 T. In 80 patients with enhancing brain lesions, contrast-to-noise ratios (C/Ns) were calculated, and lesion-to-brain contrast was evaluated visually. Six patients (6%) in each dose group reported adverse events. Eight adverse events occurred with 0.1 mmol/kg and seven with 0.3 mmol/kg. Vital signs and laboratory values did not change significantly. C/N (P < .05) and visual assessment ratings were higher with 0.3 mmol/kg than with 0.1 mmol/kg. According to these preliminary results, 0.3 mmol/kg gadopentetate dimeglumine is safe and well tolerated when administered at approximately 1 mL/sec.

Adult↗
PubMed1992

[Role of current diagnostic procedures in gastroenterology: MRI].

The diagnostic value of magnetic resonance imaging (MRI) in gastroenterology has not been definitely defined. In focal liver lesions MRI has a high sensitivity and aids in the differential diagnosis. In pathologies of the gall bladder and the pancreas, MRI currently has no clinical relevance. MRI diagnosis of pelvic fistulas and abscesses in chronic inflammatory bowel disease is both sensitive and specific. MRI is superior to CT in detecting and differentiating recurrent rectal cancer.

Diagnosis, Differential↗
PubMed1992

[Oral contrast media for the magnetic resonance tomography of the abdomen. A clinical trial of the tolerance for gadolinium-DTPA].

Safety and efficacy of gadopentetate-dimeglumine (Gd-DTPA) as a MR bowel contrast agent were determined in 133 patients with CT-proved abdominal and retroperitoneal mass lesions using a buffered formulation (1 mmol/l Gd-DTPA, 15 g/l mannitol, 25 mmol/l sodium-citrate, 6-17 ml/kg). Short-lived gastrointestinal side effects were noted in 32% of patients. Gd-DTPA provided uniform, hyperintense bowel labelling and contrast enhancement in the region of interest in 81% of patients. Among 78 patients with pre- and postcontrast images lesion delineation was improved in 62%. In 55 studies with postcontrast images only, Gd-DTPA proved useful in 65%. In 105 of 109 cases IV injection of scopolamine or glucagon eliminated image artifacts arising from peristalsis of opacified bowel. The authors conclude that Gd-DTPA is a safe and effective MR bowel contrast agent.

Abdomen↗
PubMed1992

[Manganese DPDP as a contrast medium for MR tomography of focal liver lesions. Tolerance and image quality in 20 patients].

Twenty patients with focal liver lesions (18 metastases, 1 hepatocellular carcinoma, 1 cholangiocarcinoma) were given manganese DPDP as part of a multicentric phase II study of paramagnetic hepatobiliary MR contrast media. 5 mumol/kg manganese DPDP were injected into 10 patients in a concentration of 50 mumol/ml or 10 mumol/ml (3 ml/min). Blood pressure, pulse rate, ECG, respiratory rate, body temperature, blood and serum parameters and the patients' subjective feelings were recorded. MRI was performed with 1.5 T using T1- and T2-weighted sequences. 6 patients reported 8 side effects (flushing, feeling of warmth, metallic taste); 7 of these were produced by the 50 mumol concentration. Two hours after injection there was a significant reduction in alkaline phosphatase which was no longer present after 24 hours. On T1-weighted images manganese DPDP resulted in marked improvement in the contrast difference between the lesions and the liver parenchyma which resulted in a marked increase in the signal to noise ratio. Comparing the two concentrations, better results were obtained by the lower concentration. Extrahepatic uptake was found in the gallbladder, duodenum, pancreas, kidneys, gastric mucosa and myocardium. Manganese DPDP in a concentration of 10 mumol/ml and a dose of 5 mumol/kg is a well tolerated contrast medium which improves the demonstration of focal liver lesions in view of its distribution and uptake. The mechanisms for the transitory side effects require further studies.

Adult↗
PubMed1992

[Magnetic resonance tomography: value and limits in gastroenterologic diagnosis].

At present, the value and limitations of magnetic resonance imaging (MRI) as a diagnostic modality in gastroenterology cannot be conclusively determined. MRI has a high sensitivity in the detection of focal liver lesions. The signal intensity of focal liver lesions on plain and contrast-enhanced T1-weighted images and on plain T2-weighted scans narrows the differential diagnosis in many cases. Imaging of the gallbladder and pancreas presently is no indication for MRI. The high sensitivity of MRI in the detection of fistulae and abscesses in Crohn's disease and the differentiation from fibrosis represents an advantage over other modalities in imaging of inflammatory bowel disease. MRI is superior to CT in differentiating recurrent rectal cancer from fibrosis. Further development of MRI and the use of contrast media for both oral and intravenous administration may offer new perspectives of MRI in the diagnosis of diseases in gastroenterology.

Digestive System Diseases↗
PubMed1991

Gadopentetate dimeglumine as a bowel contrast agent: safety and efficacy.

To determine the safety and efficacy of gadopentetate dimeglumine as a bowel contrast agent, magnetic resonance (MR) imaging (0.5 T) was performed with a formulation of gadopentetate dimeglumine (1.0 mmol/L of gadopentetate dimeglumine, 15 g/L of mannitol, 6-17 mL/kg) in 133 patients with intraabdominal mass lesions. Mostly short-lived gastrointestinal side effects were noted in 32% of patients. Gadopentetate dimeglumine provided uniform hyperintense marking of the bowel and contrast enhancement in the region of interest in 81% of patients. Among 78 patients with images obtained both before and after administration of contrast material, post-contrast improvement of lesion delineation was found in 62%. Among 55 patients with only postcontrast images, gadopentetate dimeglumine proved useful in 65%. Intravenous injection of scopolamine or glucagon effectively eliminated "ghost" images of the opacified bowel in 105 of 109 cases. The authors conclude that gadopentetate dimeglumine is a safe and effective bowel contrast agent for MR imaging.

Adolescent↗
PubMed1991

[Value of magnetic resonance tomography in gastroenterological diagnosis].

The value of magnetic resonance imaging (MRI) in the gastrointestinal tract has not yet been determined. In neoplastic disease, MRI has a high sensitivity in the detection of liver metastases secondary to colorectal cancer. MRI is superior to CT in differentiating recurrent rectal cancer from fibrosis. The high sensitivity of MRI in the detection of fistulae in Crohn's disease and the differentiation from fibrosis represents an advantage over other modalities in imaging of inflammatory bowel disease. Further development of MRI and the use of contrast media for both oral and intravenous administration may offer new perspectives of MRI in diseases of the gastrointestinal tract.

Gastroenteritis↗
PubMed1990

Contrast-enhanced magnetic resonance imaging of the abdomen and pelvis.

Contrast media in magnetic resonance imaging (MRI) of the abdomen and pelvis are applied for various purposes; different substances and forms of application must be distinguished. Oral contrast agents are primarily used to enhance the discrimination of the intestine from the other organs and from pathological lesions. Clinical studies of i.v. contrast agents focus on two substances: gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) and superparamagnetic iron oxide. Whereas dynamic Gd-DTPA-enhanced MRI improves the differential diagnosis of focal hepatic lesions, iron oxide is a promising agent for increasing the sensitivity of MRI in the detection of hepatic and splenic tumors. Dynamic Gd-DTPA-enhanced MRI of the kidney allows functional assessment of this organ; good demarcation of kidney tumors is only achieved during the early phase of a dynamic examination. In the assessment of adrenal lesions, dynamic Gd-DTPA-enhanced MRI permits better differentiation of adenoma from malignancy. Intravenous Gd-DTPA also appears to be useful in the staging of urinary bladder tumors to distinguish between superficial and infiltrating tumors. Although offering no major diagnostic advantage in the staging of cervical carcinomas, Gd-DTPA-enhanced MRI improves the discrimination of necrotic tumor portions of endometrial carcinoma and allows good differentiation of this lesion from fluid retained in the uterine cavity. Studies of new contrast agents for MRI of the abdomen, which have so far only been investigated in animal experiments, focus on liver imaging. These substance include hepatobiliary agents, Gd-DTPA-containing liposomes, and paramagnetic macromolecules.

Abdomen↗
PubMed1989

Comparison of multi echo and contrast-enhanced MR scans: image contrast and delineation of intracranial tumors.

In 56 patients with intracranial tumor T2-weighted multi echo (ME) [TR: 1600 ms, TE: 30 to 240 ms (8 echoes)] and T1-weighted Gd-DTPA-enhanced images (TR: 400 ms, TE: 30 ms or 35 ms) were compared with respect to tumor contrast and tumor delineation. In subgroups of 20 and 14 patients, respectively, tumor/brain- and tumor/edema-contrast were assessed on both a subjective and a quantitative basis (contrast-to-noise ratio, CNR). CNR's for tumor/brain-contrast were significantly higher on Gd-DTPA enhanced images than on ME scans. No significant differences between techniques were found for CNR's of tumor/edema-contrast. ME images yielded pathological findings in 54 of the 56 patients but visually assessed tumor delineation was achieved in only 36 cases. Fifteen out of 25 intraaxial tumors and 5 out of 31 extraaxial tumors could not be sufficiently delineated on ME images. In contrast, Gd-DTPA-enhanced images provided differentiation of tumor and surrounding tissues in 55 of 56 studies. In conclusion, ME images have proved highly sensitive in detecting intracranial lesions. However, brain tumors, especially intraaxial tumors could often not be differentiated from adjacent tissues on ME images. After Gd-DTPA, T1-weighted images provided more reliable tumor detection and delineation.)

Adolescent↗
PubMed1989

[Imaging diagnosis of aggressive fibromatosis and the MRT-pathological correlation].

Aggressive fibromatoses (desmoid tumours) tend to grow in an infiltrative and destructive manner without metastases. Computed tomography of aggressive fibromatoses yields no uniform attenuation pattern. The tumours are typically isodense when no contrast medium is used and enhance clearly to hyperdense during infusion of contrast medium. In magnetic resonance tomography (MRT) a high signal (long T2) on T2-weighted pulse sequences as well as an accumulation of i.v. Gd-DTPA seems to be the characteristic appearance of aggressive fibromatoses, although different signal intensities can be seen. The MRT histopathologic correlation shows increasing signal intensities on T2-weighted sequences dependent on an increment in cellular content of the tumours. Only histopathological methods can provide a definite diagnosis.

Adolescent↗