Normal Brain Anatomy Research Articles

Delayed Unilateral Post-Traumatic Tremor: Localization Studies Using Single-Proton Computed Tomographic and Magnetic Resonance Spectroscopy Techniques

We present the case of a 46-year-old former U.S. Marine who developed unilateral dystonic tremor responsive to anticholinergic medications 13 years after contralateral, combat-induced head trauma. Although conventional neuroimaging techniques showed normal brain anatomy, single-proton computed tomographic scans demonstrated hypometabolism ipsilateral to the area of old trauma. Proton echoplanar spectral imaging demonstrated decreased signal in this same area on creatine imaging, which normalized on anticholinergic medication. Choline imaging on medication showed a signal void in the clinically suspected basal ganglia-thalamus region. We believe that these results indirectly suggest a trans-synaptic origin of the patient's movement disorder.

Brain Imaging in Psychiatry

Brain Imaging in Psychiatry by Shon Lewis and Nicholas Higgins , 326 pp., ill., Oxford, Blackwell Science Ltd, 1996, $99.95 Chapters in this book are devoted to two major topics: explanation of various neuroimaging methods and reviews of neuroimaging research in psychiatric disorders. In addition, there are chapters on the history of brain imaging and on normal brain anatomy. The book is intended for clinical and academic psychiatrists at all levels, including those who have no detailed knowledge of brain imaging. In general, the chapters explaining neuroimaging methods (including CT, MRI, fMRI, PET, SPET, MRS, EEG, and MEG) will serve as excellent references for investigators who want to more fully understand these methodologies. Some chapters, however, contain detail that will be difficult to understand for those without a fairly sophisticated background in …

Magnetic resonance imaging of the brain of normal neonatal foals.

Magnetic resonance imaging (MRI) was performed on the brain of 5 normal, anesthetized, neonatal (age 3-to-6 days) Quarter Horse foals. The objectives of the study were to develop a technique for imaging the brain of neonatal foals, and to ascertain their normal brain anatomy. Intravenous propofol was administered for induction and maintenance of general anesthesia. Using spin echo MR techniques, T1 weighted sagittal and transverse views, and spin density and T2 weighted transverse views were successfully made of each foal. MR images provided excellent visualization of many anatomic structures of the brain and head. MRI of the brain is feasible for selected neonatal equine patients.

Posterior fontanelle cranial ultrasound: anatomic and sonographic correlation.

The purpose of this study was to correlate normal brain anatomy as seen on posterior fontanelle cranial sonography with anatomical sections of the premature infant brain. Images obtained from 93 cranial ultrasound examinations performed via both the anterior and posterior fontanelle in 53 infants, ranging in gestational age from 24 to 42 weeks, were reviewed to determine the ultrasound anatomy visible and also the changing appearances with increasing gestational age. The brains of five infants were sectioned at post-mortem according to predetermined anatomical landmarks to correlate with posterior fontanelle ultrasound scan planes. Brain preservation techniques involved fixation in formalin at room temperature, refrigeration of brain following formalin fixation, and brain freezing at -17 degrees C. In the premature infant brain, the subarachnoid space is up to 15 mm in thickness. Occipital lobe anatomy well seen includes occipital horns of lateral ventricles, and white matter tracts to the visual cortex and visual association areas. Brain anatomy was better appreciated on sections obtained following brain freezing rather than formalin fixation. Satisfactory ultrasound anatomic correlation of the premature brain is possible using a brain freezing preservation technique. Posterior fontanelle ultrasound allows detailed illustration of occipital lobe anatomy.

Assessment of cerebral perfusion with single-photon emission tomography in normal subjects and in patients with Alzheimer's disease: effects of region of interest selection

The shape, size and location of regions of interest (ROIs) show considerable variability between single-photon emission tomography (SPET) studies in aging and Alzheimer's disease, but the possible influence on study results remains unknown. We compared three different ROIs in a SPET study with 60 controls and in 48 patients with probable Alzheimer's disease diagnosed according to the NINCDS-ADRDA criteria. Regional cerebral blood flow (rCBF) was assessed with SPET using technetium-99m d,l-hexamethylpropylene amine oxime (99mTc-HMPAO), normalized to the mean activity in a cerebellar reference slice. The three different ROIs were: a multi-slice and a single-slice ROI with reference to the normal brain anatomy (using an anatomical atlas), and a rectangular (2 x 4 pixels) ROI in the frontal, temporal, temporoparietal and occipital cortices. No differences were observed for the means of rCBF values between the single-slice and multi-slice ROI's with reference to the normal anatomy, but some variability was present for individual comparisons. In contrast, significantly higher mean rCBF values were obtained with the single-slice rectangular ROIs in all four regions for both patients and controls and considerable variability was shown for individual subjects. After analysis with multivariate logistic regression and receiver operator characteristic curves, the ability of SPET to discriminate between controls and Alzheimer patients was similar in the three methods for mild and moderate Alzheimer patients (Global Deterioration Scale = GDS of 3 and 4). However, with increasing dementia severity (GDS > 4) the rectangular ROIs showed lower ability to discriminate between groups compared to the single-slice and multi-slice anatomically defined ROIs.(ABSTRACT TRUNCATED AT 250 WORDS)

Neuromagnetic mapping of brain function.

Magnetic source imaging, a technique that combines magnetoencephalography (MEG) and magnetic resonance (MR) imaging, was used to localize the somatosensory and auditory cortex in seven healthy subjects. Functional neuromagnetic data were obtained with a 37-channel biomagnetometer. Structural MR imaging data were obtained with a 1.5-T superconducting imager. Coordinates used in defining MEG and MR imaging space were reconciled to produce magnetic source images that displayed the putative locations of somatosensory and auditory activity in relation to brain anatomy. Sources of somatosensory activity were typically localized to the postcentral gyrus; sources of auditory activity were localized to the superior temporal plane. Extension of these results to patients with tumors (or other disorders) that distort normal brain anatomy has the potential to make noninvasive magnetic source imaging examinations clinically useful in guiding neurosurgical interventional procedures.

Demonstration of specific neuronal cell groups in rat brain by β-galactosidase enzyme histochemistry

β-Galactosidase activity as illuminated by the indigogenic X-gal staining method has been used to demonstrate the presence of genetically modified cells carrying the reporter gene IacZ, coding for the E. coli enzyme. Endogenous activity has been assumed to be minimal since the pH optimum for the mammalian enzyme is 3.5–5.5, while the pH optimum for the E. coli enzyme (and thus of the staining procedure usually employed) is 7.3. Background staining has been reported to be limited to pericytes and a few specific neuronal cell groups. In contrast, our investigations of normal rat brain anatomy demonstrate that many specific neuronal cell groups possess endogenous β-galactosidase activity when staining is performed at physiological pH. This suggests that background staining of endogenous β-galactosidase activity in the rat brain has been underestimated. In addition, such specific activity would afford an additional means of identification and illustration of these cells.

Epilepsy in children with attention deficit disorder: Cognitive, behavioral, and neuroanatomic indices

Our study examined the hypothesis that if epilepsy adversely influences the cognitive and behavioral performance of children, then children with both attention deficit-hyperactivity disorder and epilepsy (ADHD-Sz) should exhibit more severe cognitive and behavioral difficulties and be more likely to demonstrate abnormalities on cranial computed tomography than ADHD children without epilepsy. We compared ADHD-Sz and ADHD patients using a variety of psychologic, behavioral, and educational measures, as well as cranial computed tomography. ADHD-Sz children scored significantly below the ADHD group on the Wechsler Intelligence Scale for Children-Revised (performance and full scale scores). In both ADHD-Sz and ADHD groups, the prevalence of learning disabilities (LD) and a variety of behavioral features were similar. Neither seizure disorder nor ADHD was associated with an increased incidence of structural abnormalities or asymmetries of the brain. These findings support the belief that epilepsy adversely affects IQ but does not appear to affect the prevalence of LD or behavioral abnormalities in ADHD children. They further support the accumulating body of data demonstrating normal brain anatomy in ADHD by computed tomography.

ULTRASONOGRAPHIC ANATOMY OF THE CANINE BRAIN

Midline or lateral craniotomies were made in the skull of six normal dogs to allow ultrasound examination of the brain. The purposes of the study were (1) to describe the normal sonographic anatomy of the canine brain and (2) to develop the use of burr hole as research tool to allow sonographic examination of the canine brain. The sonographic appearance of the falx cerebri, splenial sulci, cingulate gyrus, callosal sulci, lateral ventricles, third ventricle, caudate nuclei, thalamus, hippocampus, cerebellum, and osseous tento‐rium were described. Results of this study suggest that the surgical creation of cranial defect is safe, reliable, and effective in providing window for ultrasound observation. The anatomic description should also allow recognition of sonographic abnormalities in the brain of dogs with persistent fontanelles.

Diagnosis of brain neuropathology in utero.

The fetal brain can be evaluated very effectively with high-resolution real-time ultrasound equipment. This paper reviews normal fetal brain anatomy with specific emphasis on artifacts of ultrasound scanning of the brain. A review of the developmental abnormalities seen in utero include ventriculomegaly, anencephaly, encephalocele, meningomyelocele, Dandy-Walker syndrome, holoprosencephaly, craniosynostosis, microcephaly, and agenesis of the corpus callosum. The destructive lesions reviewed include hydranencephaly, infection, intracranial hemorrhage, and mass lesion. Identification of these abnormalities can be extremely helpful in providing the patients with management options and providing the obstetrician with information which can help in obstetric and neonatal therapy.

Indications for magnetic resonance tomography in the diagnosis of cerebral diseases. Report of experiences with 1200 cases

The current paper is a review of our experience of 1200 examinations of the brain, using magnetic resonance tomography (MRT), derived from a mixed neurological and neuro-surgical clinic. MRT has advantages in localisation and tissue characterisation. Localisation is improved by the ability to obtain coronal and sagittal images and by the absence of artifacts due to bone in lesions in the middle and posterior fossa. Some tissues and structures (blood, fat, vessels) produce relatively characteristic signals on MRT, which may be important in clinical diagnosis (eg. chronic subdural haematoma). A significant advantage of MRT is its excellent contrast resolution of soft tissues; this results in better demonstration of normal brain anatomy (eg. corticomedullary contrast), areas of demyelinisation (eg. multiple sclerosis) and certain cerebral tumours (eg. astrocytomas). On the basis of our experience, certain indications are defined, depending on the physical characteristics of the method; these are illustrated by clinical examples.

Detailed sonographic mappings of normal fetal brain anatomy in utero at six levels in the axial plain.

An investigation of real time sonographic features of the normal fetal brain at six levels in the axial plain was undertaken between the 26th and 40th week of gestation. Structures such as cerebrum, midbrain, basal ganglia, ventricular system, vascular system, and cerebellum can be routinely identified if ultrasound is performed systematically. The sonographic appearance of detailed brain anatomy at each level is presented with the hope that it may provide a systematic form of scanning the fetal brain. With such standardization of technique many erroneous interpretations may possibly be avoided.

Ultrasonographie normale et pathologique du cerveau foetal

Advanced ultrasonic technology enabled the bidimensional imaging of fetal brain throughout pregnancy. The number of visible structures increases with gestational age. In order to certify the described items they were compared to similar anatomical sections available from brain specimens or an atlas of anatomy. Real-time as well as automatic compound scanning machines were used to obtain echographic images of fetal brain anatomy in utero. Many different scans were collected along three orthogonal directions: every 2 mm, with the automated compound scan and as close from each other as possible with the linear array real-time scanner. The material included 59 normal fetuses between the 15th and 40th week of gestation. Eight typical sections are made but the only structures identified are those being visible on every section obtained at the same level. Brain structures such as grey and white matter, nuclei, vessels and ventricles have different sonic properties. They are subsequently distinguishable on the ultrasonic image if the equipment is capable of detecting and showing such differences. Grey matter is more echogenic than white, choroid plexuses are very reflective as are vessel walls which also pulsate. Four horizontal sections are described in detail (Figs. 2–7). The coronal planes are demonstrated at three different levels (Figs. 8–12) and the sagittal plane is represented by Fig. 13. Thirty five structures were identified (Table 2). In the second section some brain and skull anomalies are briefly described. The principal signs of the abnormalities and possible encountered variations are listed such as cranial defects in anencephaly, acrania, encephalocele, iniencephaly; the anomaly of size and shape of head and ventricle, as in hydrocephaly and microcephaly, cystic-like- and solid-tumor lesions and Dandy Walker syndrome and hydranencephaly. Attention is drawn to possible artifacts and pitfalls in the differential diagnosis between similar looking pictures. Examples are given such as noise in the near field, occurring more often in sectorscan machines, inadequate orientation of scan plane producing asymetrical display of the hemisphere and the Sylvian fissure described as if it was the lateral ventricle wall. Anomalies can also be confused such as exencephaly, anencephaly, iniencephaly, encephalocele. An excellent knowledge of normal brain anatomy and pathology, together with excellent equipment and a careful scrutiny of the echograms are required qualities for fetal brain examination.

Normal infant brain anatomy: correlated real-time sonograms and brain specimens.

An investigation of the identifiable real-time sonographic features of the normal infant brain in the horizontal, coronal, inclined coronal, and midsagittal planes was undertaken. Correlations were made of sonograms of intact brains in vitro, corresponding brain sections, and sonograms in vivo. A large number of anatomic structures could be consistently depicted including cisterns, fissures, faix cerebri, tentorium cerebelli, ventricles, brainstem, cerebellum, basal ganglia, thalami, and corpus callosum. Pulsations of intracranial arteries, visible by real-time sonography, were of considerable help in identifying various structures. The investigation provides a reference of sonographic anatomy of the brain displayed in four clinically useful imaging planes.

Neuroradiology of the normal and pathological anatomy of the rat brain.--III Morphology and growth behaviour of experimental brain tumours following radiation therapy (author's transl)

Radiation induced (30 Gy) morphological changes of experimental malignant brain tumors, which were produced by chemical carcinogenesis, were investigated by microangiography and correlated with the histological findings in 62 BD-IX-rats. In randomized groups the investigations were performed 2, 3, 6 and 8 weeks after the radiation was finished. Morphologically different reactions could be differentiated: remissions or partial recovery of the tumors, rest or recurrent tumor and uninfluenced tumor growth. The characteristic findings, the reasons for different courses and possible conclusions concerning the radiotherapeutical effect are discussed.

Computed Tomography of the Brain in Axial, Coronal, and Sagittal Planes

Computerized tomography (CT) has revolutionized the practice of neuroradiology and related clinical sciences. There is a new emphasis on cross-sectional anatomy in normal and pathological conditions. Improved technology has produced images of superior quality, as well as the capacity to reconstruct images in coronal and sagittal planes. The authors of Computed Tomography of the Brain have presented a reference atlas of normal brain anatomy in all of these planes. Superb quality photographs of gross specimens with extensive labelling are cut to correspond to comparable CT images, presented side by side. The specimens are from normal formalin-fixed brains that have been processed to eliminate ventricular air. The bony calvarium has been removed to reduce artifacts. The majority of scans were obtained on an early generation scanner (EMI Mark I 160X 160 matrix). The quality of the CT scans, although adequate, is considerably inferior to the images of current generation scanners. This

Microsurgery of tumours of the frontal white matter.

Seventy eight microsurgical extirpations of tumours located in the frontal white matter led to adjustment of the normal anatomy of the frontal brain according to microsurgical requirements, and also to relation with modern diagnostic procedures, especially computerized tomography (CT-scanning). The advantages of microsurgical treatment have been demonstrated. Thus, only exact comprehension of topographical anatomy allows a methodical, careful, and radical procedure. As vessels were commonly saved, postoperative courses were relatively benign because of less tendency to oedema. Out of 78 patients, 3 died while in hospital, and two recurrences were observed in the following 23 months. Postoperatively 51 patients improved, 18 stayed unchanged neurologically, and 9 patients deteriorated permanently. The usual microsurgical instruments were employed. Vascular problems were dealt with by the routine techniques used at our hospital.