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Biomedical subjects

J Lissner

Publications and source records attributed to J Lissner.

170 records · Page 10Linked to original sources
PubMedDate not supplied

MR imaging in pediatric airway obstruction.

Magnetic resonance (MR) imaging of the trachea was performed in 27 children with congenital tracheal narrowing. The diagnoses included aortic arch anomalies (n = 7), innominate artery compression (n = 13), pulmonary artery compression (n = 5), and tracheomalacia (n = 2). Demonstration of the trachea and the surrounding tissue and vessels on MR images allowed the evaluation of the cause of tracheal compression and the degree and location of collapse. Patients were examined with MR imaging if the cause of airway obstruction was still unclear after bronchoscopy. It is concluded that MR imaging is a well suited modality for characterizing tracheal narrowing without using ionizing radiation or intravenous contrast medium.

Airway Obstruction↗
PubMedDate not supplied

MRI in pre- and postoperative assessment of tracheal stenosis due to pulmonary artery sling.

OBJECTIVE: To evaluate the potential of MRI in the assessment of tracheal stenosis due to tracheal or vascular malformations, 45 children with severe respiratory distress were examined prospectively during a period of 1 year. Five of these children had tracheal stenosis due to a sling left pulmonary artery (SLPA). MATERIALS AND METHODS: Magnetic resonance examinations of the anesthetized children were performed with a 1.5 T Siemens MR imager using electrocardiographically gated T1-weighted SE sequences in transverse and sagittal slice orientations. Slice thickness was 3 mm and each sequence was repeated after shifting the slice position by 1 mm. Monitoring during the examinations included ECG, oscillatory blood pressure, respiratory rate, and oxygen concentration. Magnetic resonance findings were compared with esophagography, selective pulmonary angiography, bronchoscopy, Doppler sonography, and surgery. All examinations were repeated after surgical therapy to assess the improvement in tracheal stenoses and the patency of the ligated and reimplanted left pulmonary arteries. RESULTS: Magnetic resonance imaging clearly revealed the course of the SLPA and its topographic relationship to the trachea as well as the coexistence of cardiovascular and tracheobronchial or esophageal malformations. The degree and length of tracheal stenoses, which were measured in the pre- and postoperative axial slices and graphically displayed, as well as the angles of the right and left main stem bronchi, could be accurately determined. CONCLUSION: Magnetic resonance imaging in combination with bronchoscopy yielded the necessary and sufficient information for diagnosis and aided the surgeon in planning operative strategy and in postoperative follow-up.

Angiography↗
PubMedDate not supplied

Influence of magnetic resonance imaging on human body core and intravascular temperature.

Deep and superficial body temperatures were measured by in vitro and in vivo experiments, using a fluoroptic procedure and a variety of magnetic and electromagnetic fields, in the course of magnetic resonance imaging (0.35 T; 1.5 T). In vitro experiments were performed to select and check the appropriate temperature method. Temperature measurements in the human body were carried out centrally (esophageal and rectal measurements). In vivo experiments in 30 volunteers showed no significant changes (p = 0.05) in central or peripheral temperatures resulting from the application of static or dynamic fields or radiofrequency.

Blood Circulation↗
PubMedDate not supplied

Tumors of the nasopharynx and adjacent areas: MR imaging with Gd-DTPA.

The purpose of this study was to describe our experience with Gd-DTPA-enhanced MR imaging in the evaluation of the most common nasopharyngeal tumors. Forty-two patients with tumors of the nasopharynx and adjacent spaces had MR imaging before and after IV injection of Gd-DTPA. Images were obtained with a 1.0-T superconducting magnet imaging system in transverse, coronal, and sagittal planes with T1- and T2-weighted sequences. MR images were compared with CT scans and tumor histology. The studies were categorized by using a grading system with grades ranging from unsatisfactory (grade 0) to optimal (grade 3). Contrast-enhanced MR enables better identification of small anatomic details such as both palatini muscles and the pharyngobasilar fascia. MR after Gd-DTPA was superior to CT in all cases except for tumors of the maxillary sinuses. MR with Gd-DTPA is recommended for tumors that are small and difficult to detect on the initial nonenhanced MR examination or that show subtle infiltrations. Because of the increased cost and longer examination time, MR with Gd-DTPA does not need to be done when large tumors are well delineated.

Carcinoma, Squamous Cell↗
PubMedDate not supplied

Third cranial nerve palsy caused by gummatous neurosyphilis: MR findings.

The clinical and MR findings in an unusual case of gummatous neurosyphilis are reported. A 44-year-old woman suffering from diplopia and right-sided headaches was admitted. Physical examination and routine laboratory parameters were normal except for a third-nerve palsy. MR images revealed a contrast-enhancing lesion of the upper brain stem and third cranial nerve. Differential diagnosis included neuroma of the third cranial nerve, as well as neurosarcoidosis and other inflammatory processes. Serologic tests and lumbar puncture revealed the presence of active syphilis. After intravenous treatment with penicillin G, follow-up MR examinations showed diminishing size of the lesion with its complete resolution within 3 months.

Adult↗
PubMedDate not supplied

MR and MR angiography of Sturge-Weber syndrome.

PURPOSE: To assess the potential of magnetic resonance angiography (MRA) as an adjunct to spin-echo sequences in evaluating the cerebral vascular anomalies seen in Sturge-Weber syndrome. METHODS: Four pediatric patients with Sturge-Weber syndrome were evaluated with conventional MR imaging and with arterial and venous MRA. Resultant images were evaluated for evidence of volume loss, cortical enhancement, vascular anomalies, and enlarged choroid plexus. RESULTS: Venous MRA revealed reduced flow of the transverse sinuses and jugular veins, prominent deep collateral venous system, and a lack of superficial cortical veins. Arterial MRA, performed in all cases, revealed a reduced flow signal from the left middle cerebral artery in one hemiparetic patient and angiomatous changes of high branches of a middle cerebral artery in two patients. CONCLUSION: Arterial and, in particular, venous MRA can be useful adjuncts to standard spin-echo sequences in diagnosing Sturge-Weber syndrome.

Brain↗