ABSTRACT
In 330 patients with a space occupying lesion of the posterior cranial fossa, the blink (BR) and masseter (MR) reflexes and brain stem auditory (BAEP) and somatosensory evoked potentials (SEP) were registered. The aim of our study was to look for electrophysiological criteria of differentiating between lesions within or outside the brain stem. The ipsilateral loss of BAEP in cerebellopontine angle tumours and the altered SEP in tumours within the brain stem turned out as frequent, almost specific findings. Prolonged ipsi-and contralateral late BR responses and prolonged MR responses, a long somatosensory central conduction time of the SEP and a prolonged wave III latency as well as a prolonged interpeak latency of the BAEP are not indicative but highly suspicious for a lesion within the brain stem. Prolonged early responses of the BR together with prolonged interpeak latencies of the BAEP are characteristic findings in cerebello-pontine angle tumours.
Subject(s)
Brain Neoplasms/physiopathology , Brain Stem/physiopathology , Electroencephalography/instrumentation , Electromyography/instrumentation , Mesencephalon/physiopathology , Blinking/physiology , Brain Neoplasms/diagnosis , Brain Neoplasms/surgery , Brain Stem/surgery , Cranial Fossa, Posterior/physiopathology , Cranial Fossa, Posterior/surgery , Diagnosis, Differential , Dominance, Cerebral/physiology , Evoked Potentials, Auditory, Brain Stem/physiology , Evoked Potentials, Somatosensory/physiology , Humans , Masseter Muscle/innervation , Mesencephalon/surgery , Reaction Time/physiology , Reference Values , Reflex, Abnormal/physiologyABSTRACT
A meningioma was incidentally identified with computerized tomography (CT) in 17 patients without relevant clinical signs. The tumor was not removed, but biopsy confirming a meningioma was obtained from one patient. Tumor growth rate was calculated from repeat CT scans or follow-up magnetic resonance imaging. The annual growth rate ranged from less than 1% to 21%. It is concluded that in nonsymptomatic meningiomas with a low growth rate a nonsurgical approach may be warranted.
Subject(s)
Meningeal Neoplasms/pathology , Meningioma/pathology , Aged , Aged, 80 and over , Female , Follow-Up Studies , Humans , Magnetic Resonance Imaging , Male , Meningeal Neoplasms/diagnostic imaging , Meningeal Neoplasms/surgery , Meningioma/diagnostic imaging , Meningioma/surgery , Middle Aged , Retrospective Studies , Risk Factors , Tomography, X-Ray ComputedABSTRACT
Artifacts are occasionally encountered on magnetic resonance imaging after operation. These may be due to minute metallic particles from neurosurgical instruments. Particles not detectable on plain x-ray films or computerized tomography scans may cause local change of magnetic resonance activity, resulting in a deceptive magnetic resonance appearance. Three illustrative case reports are presented.
