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Biomedical subjects

M Kunnen

Publications and source records attributed to M Kunnen.

At least 37 records · Page 2Linked to original sources
PubMed1999

Imaging of the normal pontine cisternal segment of the abducens nerve, using three-dimensional constructive interference in the steady state MRI.

Our objective was to determine the visibility of the cisternal segment of the normal abducens nerve using a three-dimensional Fourier-Transform constructive interference in the steady state (3DFT-CISS) sequence. Its visibility was rated in 150 patients without clinical evidence of abducens nerve disturbance. Axial 1-mm 3DFT-CISS images were obtained (TR/TE 17/7 ms, flip angle 50 degrees, field of view 160 mm, matrix 256 x 256). The cisternal segment was seen in 79% of cases, bilaterally in 73% and unilaterally in 11% of cases; neither cisternal segment was seen in 16% of cases. Identification of Dorello's canal was often of help in detecting the point lateral to the dorsum sellae at which the nerve pierces the dura mater. Flow artifacts and vascular loops in the pontine cistern sometimes caused problems in interpretation. 3DFT-CISS MRI with 1-mm-thick sections can however be considered a reasonably reliable technique for showing the cisternal segment of the abducens nerve.

Abducens Nerve↗
PubMed1999

Rupture of a cervical spinal cord arteriovenous malformation: a rare complication of endovascular embolization.

Patients suffering from a cervical spinal cord arteriovenous malformation (SCAVM) run high risk of devastating subarachnoid hemorrhage and hematomyelia. Therefore, cervical SCAVMs represent a compelling indication for surgical or endovascular therapy. The authors report on an acute life-threatening subarachnoid hemorrhage from a cervical SCAVM that ruptured during an embolization procedure. Causality and therapeutic management are discussed.

Acute Disease↗
PubMed1999

Non-invasive diagnostic assessment of extensive vertebral artery tortuosity with enlargement of the intervertebral foramen.

Two cases with an incidental finding of a widened intervertebral foramen due to extensive tortuosity of the vertebral artery are presented. Computed tomography angiography and magnetic resonance imaging/magnetic resonance angiography (MRA) both proved to be useful as non-invasive techniques to provide the diagnosis. In-plane saturation is a disadvantage seen with the two-dimensional time-of-flight MRA technique.

Adult↗
PubMed1999

MRI prior to major tumor surgery in the head and neck.

MRI plays an important and specific role prior to tumor surgery in the head and neck region. It is especially interesting in providing a detailed description of the exact tumor extent close to the skull base and to investigate perineural and perivascular tumor spread. In selected cases this technique can give a presumed histopathological diagnosis for a mass that is clinically detected. This is especially true for some benign masses, such as hemangiomas, cysts and lipomas. The role of MRI with regard to a lymph node imaging survey in the neck is rather limited. MRI is moreover not routinely performed in neck regions where many motion artifacts can be expected, such as in the larynx.

Head and Neck Neoplasms↗
PubMed1999

Posttraumatic subdural hygroma: CT findings and differential diagnosis.

Subdural hygroma is a cerebrospinal fluid accumulation in the subdural space. It is an epiphenomenon of head injury. CT is the preferred diagnostic imaging modality. Differential diagnosis has to be made with chronic subdural hematoma, and atrophy with enlargement of the subarachnoid space. As time goes by, subdural hygroma either resolves, or it becomes a chronic subdural hematoma. Neurosurgical evacuation is only required when mass effect creates neurologic symptoms.

Aged↗
PubMed1999

An undescribed coexistence of a subserosal exophytic gastric leiomyoma with a serous microcystic pancreatic adenoma.

We present the case of a 66-year-old woman with complaints of odynophagia but normal gastro-oesophagoscopic findings. On computed tomographic examination, a presumptive diagnosis of a cystic liver tumor and a microcystic pancreatic adenoma was made. Histopathological examination of the hepatic mass, however, revealed a subserosal exophytic gastric leiomyoma. Considerations to avoid the potential pitfall of diagnosing an exogastric leiomyoma as a liver tumor are emphasized. Moreover, the unique association of an exogastric leiomyoma and a serous microcystic pancreatic adenoma is discussed.

Adenoma↗
PubMed1999

Leptomeningeal metastases from ethmoid sinus adenocarcinoma: clinico-radiological correlation.

A patient with sinonasal adenocarcinoma is presented with leptomeningeal metastases affecting multiple cranial nerves and spinal nerve roots. Head and neck cancer is known to be an extremely rare source for leptomeningeal metastatic spread. The cranial nerves, the spinal cord and roots and the cerebral hemispheres can be affected in case of leptomeningeal metastatic spread. Examination of the CSF is the hallmark of the diagnosis if leptomeningeal metastatic spread is suspected, but this case illustrates that the combination of specific clinical features on one hand and specific lesions on the Gd-enhanced T1-weighted MRI study on the other hand is reliable enough to make a presumed diagnosis if the CSF analysis remains negative. We suggest that in our patient direct leptomeningeal spread occurred through the cribriform plate to the CSF, followed by further spread in a gravity dependent way.

Adenocarcinoma↗
PubMed1998

Ossified retroperitoneal malignant Schwannoma with spinal leptomeningeal metastases.

A malignant retroperitoneal schwannoma in a patient without von Recklinghausen's disease is reported. Ossification in the tumour, shown on CT and MRI in this previously untreated patient is exceptional. MRI demonstration of spinal leptomeningeal metastases supports the hypothesis of haematogenous metastatic spread of systemic malignant tumours to the leptomeningeal spaces.

Female↗
PubMed1998

Schwannoma of the tip of the nose: MRI.

We report a schwannoma with a rare location at the tip of the nose in a 20-year-old woman with an otherwise unremarkable medical history. The imaging findings underline the usefulness of MRI in narrowing down the differential diagnosis of masses in this region. Once the diagnosis was focussed on a neural origin of the mass, the exact nature of the tumour could not be predicted from the MRI, although the presence of a capsule on imaging studies as well as at operation suggested it was probably a schwannoma. A schwannoma must be considered when one encounters a sharply delineated mass at the tip of the nose, showing high signal on T2-weighted images and strongly contrast enhancement.

Adult↗
PubMed1998

Secondary superficial siderosis of the central nervous system in a patient presenting with sensorineural hearing loss.

We present a 50-year-old man who was investigated for sensorineural hearing loss. On MRI of the brain superficial siderosis of the central nervous system was seen, while MRI of the spine revealed an ependymoma of the cauda equina. This case illustrates the importance of performing T2-weighted imaging of the brain and posterior fossa when sensorineural hearing loss is present. Spine imaging is mandatory when superficial siderosis of the brain is diagnosed without identification of a bleeding source in the brain.

Brain↗
PubMed1998

CT of the temporal bone in the CHARGE association.

We reviewed the CT examinations of the temporal bone, performed with 1-mm-thick contiguous sections, of seven patients with the CHARGE association. We found abnormalities of the incus and stapes, with ossicular chain fixation, absence of the stapedius muscle and oval window, hypoplasia or dysplasia of the vestibule and absence of the semicircular canals in all ears. The pyramidal eminence and tympanic sinus were absent and there were anomalies of the cochlea in 13 of 14 ears. Absence of the semicircular canals is the most specific change in patients with the CHARGE association.

Abnormalities, Multiple↗
PubMed1998

Intra- and interobserver variability of MRI-based volume measurements of the hippocampus and amygdala using the manual ray-tracing method.

We studied the intra- and interobserver variability of volume measurments of the hippocampus (HC) and the amygdala as applied to the detection of HC atrophy in patients with complex partial seizures (CPE), measuring the volumes of the HC and amygdala of 11 normal volunteers and 12 patients with presumed CPE, using the manual ray-tracing method. Two independent observers performed these measurements twice each using home-made software. The intra- and interobserver variability of the absolute volumes and of the normalised left-to-right volume differences (deltaV) between the HC (deltaV(HC)), the amygdala (deltaV(A)) and the sum of both (deltaV(HCA)) were assessed. In our mainly right-handed normals, the right HC and amygdala were on average 0.05 and 0.03 ml larger respectively than on the left. The interobserver variability for volume measurements in normal subjects was 1.80 ml for the HC and 0.82 ml for the amygdala, the intraobserver variability roughly one third of these values. The interobserver variability coefficient in normals was 3.6% for deltaV(HCA), 4.7% for deltaV(HC) and 7.3% for deltaV(A). The intraobserver variability coefficient was 3.4% for deltaV(HCA), 4.2% for deltaV(HC) amd 5.6% for deltaV(A). The variability in patients was the same for volume differences less than 5% either side of the interval for normality, but was higher when large volume differences were encountered, is probably due to the lack of thresholding and/or normalisation. Cutoff values for lateralisation with the deltaV were defined. No intra- or interobserver lateralisation differences were encountered with deltaV(HCA) and deltaV(HC). From these observations we conclude that the manual ray-tracing method is a robust method for lateralisation in patients with TLE. Due to its higher variability, this method is less suited to measure absolute volumes.

Adolescent↗
PubMed1998

Coexistence of an adrenocortical carcinoma with an abdominal ganglioneuroma in a child.

We report a 3-year, 5-month-old boy with an adrenocortical carcinoma. These tumours are rare and highly malignant in childhood. In most cases they are functional, secreting adrenocortical hormones. In this case there was a misleading coexistence with a second abdominal neoplasm, which was a ganglioneuroma; this is a rare benign tumour arising from the sympathetic nervous system. The imaging investigations and their findings are discussed and correlated with pathology.

Abdominal Neoplasms↗
PubMed1998

Laryngeal embryonal rhabdomyosarcoma in a child: MRI appearance.

We report a rare case of a young girl with an embryonal rhabdomyosarcoma of the right aryepiglottic fold. Local disease recurrence, occurring 7 years after subtotal resection and adjuvant chemotherapy, was studied with plain radiography, CT and MRI. To the best of our knowledge, this is the first report illustrating the MRI characteristics of a laryngeal embryonal rhabdomyosarcoma in a child.

Child↗
PubMed1998

Single-voxel proton MR spectroscopy and positron emission tomography for lateralization of refractory temporal lobe epilepsy.

PURPOSE: We compared the metabolic information obtained from single-voxel proton MR spectroscopy and positron emission tomography (PET) in patients with temporal lobe epilepsy. METHODS: Twenty-nine patients with temporal lobe epilepsy were screened for metabolic abnormalities with both proton MR spectroscopy and PET. Lateralization with MR spectroscopy was possible by using NAA/(Cho+Cr) and an asymmetry index. Hypometabolism as determined by PET was classified as typical or complex. RESULTS: Twenty-four (96%) of 25 patients whose seizure onset could be lateralized to one temporal lobe showed ipsilateral lateralization with either MR spectroscopy or PET, whereas concordant lateralization with both techniques was possible only in 14 (56%) of the 25 patients. MR spectroscopy showed 42 abnormal temporal lobes whereas PET showed only 25 lobes with decreased metabolism. All temporal lobes with hypometabolism at PET also had a low NAA/(Cho+Cr). Five patients (20%) with negative PET studies had seizures lateralized correctly with MR spectroscopy. CONCLUSION: Proton MR spectroscopy is more sensitive in depicting metabolic abnormalities than is PET in patients with temporal lobe epilepsy. Patients with negative PET studies will benefit from MR spectroscopy for the purpose of lateralization.

Adolescent↗
PubMed1997

Iopentol (Imagopaque 350) compared with iohexol (Omnipaque 350) in pediatric cardioangiography. A clinical trial assessing adverse events, ECG, blood pressure and diagnostic information.

A non-ionic, monomeric, low-osmolar contrast medium, iopentol (Imagopaque, Nycomed Imaging AS, Oslo, Norway) has been compared with iohexol (Omnipaque, Nycomed Imaging AS, Oslo, Norway) in a double-blind, randomized, parallel-group trial in children. The aims of the study were to compare the safety and radiographic efficacy of iopentol 350 mg I/ml versus those of iohexol 350 mg I/ ml in pediatric cardioangiography. Seventy-three children, of whom 35 received iopentol and 38 iohexol, were included in the evaluation. The quality of overall diagnostic information was excellent or adequate in all patients. There were no statistically significant differences between numbers of patients reporting adverse events nor number of patients reporting discomfort in the two groups. Three patients in the iopentol group and two patients in the iohexol group reported adverse events. Heat sensation was reported by 4 patients in the iopentol group and 5 patients in the iohexol group. Following injection of contrast medium, there were no differences between the groups regarding ECG, heart rate and systolic blood pressure at the site of injection. Iopentol was demonstrated to be as effective, safe and well tolerated as iohexol in pediatric cardioangiography.

Adolescent↗