Biomedical subjects

L te Strake

Publications and source records attributed to L te Strake.

13 recordsLinked to original sources

PubMed1991

MR imaging in hydatid disease.

Hydatid cysts may develop anywhere in the body as a result of the presence of a viable parasite (Echinococcus granulosus). Depending on the condition of the parasite, the host reaction, and therapy, the hydatid cyst will degenerate and may eventually collapse, leaving an area of calcification in the host tissue. The purpose of this pictorial essay is to demonstrate the use of MR imaging in the diagnosis of the various stages of hydatid disease and in monitoring response to therapy.

Albendazole↗

PubMed1990

Magnetic resonance imaging of thoracic hydatid disease. Correlation with clinical findings, radiography, ultrasonography, CT and pathology.

Two patients with thoracic manifestations of hydatid disease (HD) are discussed; one patient had recurrent HD of the chest wall and the other, intrapulmonary HD after rupture and intrathoracic extension of an infradiaphragmatic cyst. At magnetic resonance (MR) imaging the manifestations of HD in the thorax are similar to previously reported MR findings in HD in the liver. The presence of a low signal intensity rim on T2 weighted images representing the cyst wall was confirmed. On T1 weighted images cysts with heterogeneous low and intermediate signal intensity contents and a relatively high signal intensity wall were seen. 'Folded parasitic membranes' previously not described on MR were noted. Daughter cysts may have a low or high signal intensity depending on contents. Reactive changes in the lung may be quite marked compared with the liver, due to reaction to the parasite or simply because the lung is more easily compressed leading to secondary atelectasis.

Adult↗

PubMed1988

Ultrasonography of the peroneal nerve muscle group in normal subjects and patients with peroneal paresis.

A method for measuring the cross-sectional area (CS area) of the peroneal nerve muscle groups (PNMG) by ultrasonography is presented. The method has a good reliability and can be performed easily. The mean value of the ratio (x 100) of the right-sided PNMG CS area to the left-sided PNMG CS area in right-handed normal subjects was 98%, with a standard deviation of 8.5%. The normal range for this value was 81%-115% (mean +/- 2 SD). Examples of these measurements in patients with peroneal pareses during denervation and reinnervation are given.

Adult↗

PubMed1988

Magnetic resonance imaging of renal transplants: its value in the differentiation of acute rejection and cyclosporin A nephrotoxicity.

The purpose of this study was to determine the value of magnetic resonance imaging (MRI) in the differentiation of acute rejection and cyclosporin A nephrotoxicity in renal transplant kidneys. Fifty-six magnetic resonance examinations in 46 patients were prospectively and independently evaluated by two radiologists. MRI was performed with a 0.5 T superconducting scanner (Gyroscan S5, Philips) applying both T1 and T2 weighted pulse sequences. Biopsies were performed in 22 cases and histology was reviewed. Fifteen normally functioning transplant kidneys and 41 kidneys with graft dysfunction due to cyclosporin A nephrotoxicity, acute rejection, chronic rejection or acute tubular necrosis were studied. Absence or reduction in cortico-medullary demarcation proved to be a sensitive, but non-specific indicator of parenchymal disease. In cases of cyclosporin A nephrotoxicity the allograft was diagnosed as being normal in 90%. The magnetic resonance appearance of acute rejection may be very similar to that of the combination of acute rejection and cyclosporin A nephrotoxicity, chronic rejection or acute tubular necrosis. However differentiation between acute rejection and cyclosporin A nephrotoxicity was possible according to the following statistical data: sensitivity 100%, specificity 75%, positive predictive value 86%, negative predictive value 100%, accuracy 90%.

Cyclosporins↗

PubMed1987

Magnetic resonance imaging of the adrenal glands.

Although CT should be used as the initial procedure, MRI potentially can identify most adrenal masses without the hazard of ionizing radiation or the injection of iodinated contrast material.

Adenoma↗

PubMed1986

Intraocular lens implants (pseudophakoi) and steelwire sutures: a contraindication for MRI?

The strong magnetic field of the super-conducting MRI (Magnetic Resonance Imaging) apparatus could cause problems in the presence of metallic foreign material, such as the metal clips and loops of intraocular lenses and steel as suturing material. If the magnetic field were to induce movement this could be dangerous for the eye. In this study these materials were tested with the 0.5 Tesla MRI and a 1.0 Tesla permanent magnet. Intraocular lenses with a platinum clip, or metallic or plastic loops, and 5 X 0/6 X 0 steelwire used as suturing material experienced no magnetic movement or change of position in the strong magnetic field. Neither did these foreign materials have any effect on the images obtained (spin-echo pulse sequence, 0.5 T Gyroscan). No artefacts were produced, the normal MRI picture of the T1-T2 calculated images, made with a special deticated eye surface coil, were obtained.

Alloys↗

PubMed1986

Application of anatomically shaped surface coils in MRI at 0.5 T.

The construction and application of eight different MRI surface coils is described. The coils consist of an anatomically shaped copper wire loop as an antenna and a printed circuit board containing electronic components for tuning and matching. The electronic device for tuning and matching is interchangeable between the various coils. Surface coils for signal detection yield images with high signal-to-noise ratio in comparison to the usual saddle-shaped head or body coils. The sensitivity of a surface coil decreases with increasing distance between the coil and the object of interest and therefore the coils are constructed to fit the anatomical structure under examination as well as possible. The application of dedicated surface coils for superficial structures in the body extends the possibilities of the MRI system. Photographs of the coils positioned on the body and MR images of volunteers and patients are shown.

Animals↗

PubMed1986

Magnetic resonance imaging of the genitourinary tract.

This is an overview of the current applications of magnetic resonance imaging (MRI) in the genitourinary tract based on the experience with the 0.5-Tesla MR scanner (Gyroscan, Philips) at the Leiden University Hospital and on reports in the literature. MRI appears to share some of the limitations of CT. MRI cannot reliably differentiate between a malignant and a benign tumor. In the staging of ovarian malignancies by means of MRI, bowel preparation would be desirable. On the other hand, the soft-tissue contrast resolution of MRI is superior to that of CT and images can be obtained in any plane. Thus MRI promises to be an accurate method for staging malignancies. The results in the examination of transplant kidneys are encouraging. We expect that there will be a place for MRI as a complementary technique to ultrasonography in the diagnosis of scrotal disease.

Female↗

PubMed1984

[NMR imaging of the kidney].

NMR imaging was performed in 18 patients suffering from various renal disorders. 2 scanners were used, a 0.14T resistive prototype system and the superconducting Gyroscan S5. NMR imaging proved to be a very sensitive technique. Tumours as small as 5-10 mm were detected. Solid tumours and cysts could be distinguished. As a result of the excellent contrast resolution and tissue differentiation NMR imaging appears to be very accurate in the staging of renal cell carcinoma. Blood vessels within a tumour may be visible as little black dots. Because of their short T1 hemorrhagic cysts can be differentiated from simple cysts. Further prospective follow-up studies are required before a definite statement can be made as to the value of NMR imaging in diffuse parenchymal disease. Calcification were not detected. NMR imaging does not seem to be any more specific as to tissue characterisation than other imaging modalities.

Female↗

PubMed1984

Nuclear magnetic resonance imaging of the kidney.

A pilot study was carried out in order to determine the possible applications of nuclear magnetic resonance (NMR) imaging in the diagnosis of renal disease. 22 patients with various benign and malignant tumors as well as renal parenchymal disease and chronic rejection in transplant kidneys were studied with a Philips resistive prototype scanner and the superconducting Gyroscan S5. Contrast resolution and therefore tissue differentiation are excellent. A hemorrhagic cyst can be differentiated from a simple cyst. Diffuse and patchy parenchymal changes are diagnosed in an objective and quantitative way. Lesions as small as 1 cm are easily detected and NMR is potentially more accurate than X-ray CT in the local staging of renal cell carcinoma. A disadvantage is the inability to detect calcifications. We conclude that NMR is a highly sensitive modality and appears to be more specific than X-ray CT and ultrasound.

Diagnosis, Differential↗

PubMed1980

Intussusception in adults.

11 cases of intussusception in adults, including 9 treated by operation, are discussed. The cause of the intussusception was a malignant lesion in 7 and a benign lesion in 2 cases. In 2 patients, reposition was achieved with the aid of a barium enema. Aetiology and clinical and radiological features are discussed. In view of the high incidence of pre-existent lesions and the risk of perforation at reposition with the aid of a barium enema, surgical therapy is indicated. The pre-existent lesions found at operation and pathological anatomical examination were: malignant lymphoma (4 cases), caecal adenocarcinoma (2 cases), leiomyofibroma of the ileum (1 case), caecal endometriosis (1 case), carcinoid appendix (1 case) and Meckel's diverticulum (2 cases).

Adult↗

PubMedDate not supplied

Abdominal applications of fast MR imaging: a comparison of fast field echo (FFE) and spin echo (SE) pulse sequences.

Fast gradient echo (GE) MR imaging during breathhold was performed in 73 abdominal MR examinations in order to determine the value of GE technique in the reduction of movement artefacts and improvement of image quality. The results were compared with conventional spin-echo (SE) technique. T1-weighted SE images consistently demonstrated normal anatomy and pathology. T2*-weighted and intermediate GE technique proved to be superior to T2-weighted SE technique in a considerable number of cases providing not only better delineation of normal structures but also better lesion detection. At this stage GE technique should be considered as an adjunct to T1-weighted SE technique. If the artefacts presently inherent to GE imaging could be reduced or compensated for, this technique of rapid MR imaging during suspended respiration could become an important tool being one of the fastest techniques for abdominal MR imaging.

Abdomen↗

PubMedDate not supplied

MR imaging of the adrenals: correlation with computed tomography.

The purpose of this study was to evaluate the role of magnetic resonance (MR) imaging in adrenal disease based on correlative imaging with CT. Fifty lesions in 36 patients with a variety of adrenal diseases were evaluated, at 0.5 T using spin echo (SE) multislice short repetition time (TR) and SE multislice multiecho long TR sequences. It is concluded that MR is capable of identifying most adrenal abnormalities previously detected by CT. The results suggest that MR has a greater specificity for mass lesions and might be useful to differentiate nonfunctioning adenomas from functioning adenomas, metastasis, pheochromocytomas, cysts, and intraadrenal hemorrhage. Magnetic resonance imaging also has the potential to detect aldosteronomas by increased signal intensity in addition to contour distortion using long TR/echo time sequences. The ability to perform multiplanar imaging and the presence of superior contrast as compared with CT are useful for the assessment of origin and extension of large lesions and the detection of pheochromocytomas in complex cases. Considering MR's limitations, we believe that at present its major role in evaluation of adrenal disease should be complementary to CT.

Adenoma↗