Subject(s)
Cerebral Angiography , Ischemic Attack, Transient/diagnosis , Magnetic Resonance Angiography , Porphyrias/diagnosis , Adult , Cerebral Infarction/diagnosis , Cerebral Infarction/drug therapy , Cerebral Infarction/genetics , Diagnosis, Differential , Female , Hemin/therapeutic use , Humans , Ischemic Attack, Transient/drug therapy , Ischemic Attack, Transient/genetics , Porphyrias/drug therapy , Porphyrias/geneticsABSTRACT
We have previously shown that 5 mm axial T1-weighted images following Gd-diethylenetriamine pentaacetic acid (DTPA) administration were sufficient as a screening examination of the internal auditory canal (IAC) and cerebellopontine angle cistern in 80% of cases with sensorineural hearing loss. In the remaining 20% of cases 3 mm slices were necessary for confirmation of the diagnosis. To reduce the number of cases requiring the additional examination, we have modified our protocol to include a coronal "scout" T1-weighted sequence followed by 5 mm axial sections angled through the IACs. Routine axial T2-weighted images of the posterior fossa were also obtained. One hundred eleven patients were studied with this protocol. In all but two of these the 5 mm sections unequivocally provided the diagnosis and in those two cases the coronal images confirmed the diagnosis suspected on the axial study. Three millimeter slices were not necessary in any patient. This three sequence, post-Gd-DTPA protocol, which requires only 12 min of scan time, is recommended as a screening protocol for IAC and cerebellopontine angle disease.
Subject(s)
Ear Canal , Magnetic Resonance Imaging , Mass Screening/methods , Neuroma, Acoustic/diagnosis , Cerebellopontine Angle/pathology , Clinical Protocols , Head , Humans , Image Enhancement , Posture , Retrospective StudiesABSTRACT
To establish the usual pattern of flow in the circle of Willis in newborns, the authors scanned 53 healthy full-term infants within 3 days of birth with color Doppler imaging. All examinations were performed and images interpreted by the same experienced individuals. The basilar, internal carotid (ICA), and anterior and middle cerebral arteries were seen in all infants. Vertebral, posterior cerebral, superior cerebellar, and posterior communicating (PCoA) arteries were seen in most infants. PCoA flow was from the ICA toward the posterior cerebral artery in 73 (98.6%) of the 74 vessels that were seen. Flow in the anterior communicating artery was seen in six infants, indicating dependence of an anterior cerebral artery on contralateral ICA perfusion. Two pitfalls involving the distal portion of the ICA were noted: This vessel could be confused with the proximal portion of the anterior cerebral artery or cavernous sinus if real-time images were not interpreted carefully. Variant patterns of flow included tortuous basilar arteries (n = 2), reversed PCoA flow (n = 1), and inferior angulation of the proximal portions of the anterior cerebral arteries (n = 2). Color Doppler imaging allows a detailed analysis of the circle of Willis in newborns and detection of some anatomic variations.
Subject(s)
Circle of Willis/anatomy & histology , Ultrasonography , Cerebral Arteries/anatomy & histology , Cerebrovascular Circulation , Humans , Infant, NewbornABSTRACT
The evaluation strategy of a medical library program within an Area Health Education Center is described. One of about thirty programs in the AHEC project, this library program was singled out as the first to be evaluated both because it was considered a key part of the total program and because a fair amount of quantitative data were available for measurement. Eleven hospitals of the thirty-nine in the area were selected for the study. Two specific and measurable objectives, the evaluation method, instruments, and results are presented. Finally, several important issues raised in conjunction with the evaluation are discussed in terms of the implications of evaluation and policy making.
