[Dorsal plate arthrodesis of the thumb metacarpophalangeal joint]. / Die Arthrodese des Daumengrundgelenks durch Plattenosteosynthese.

OBJECTIVE: Elimination of pain or instability by arthrodesis of the thumb joint in functional position by dorsal plateosteosynthesis. INDICATIONS: Painful primary or secondary arthrosis of the thumb, nonreconstructable ulnar, radial or palmar instability, posttraumatic dislocation, defect injuries, bone tumors in the region of the thumb metacarpophalangeal joint. CONTRAINDICATIONS: Local infection of the thumb metacarpophalangeal joint area. SURGICAL TECHNIQUE: Dorsal approach to the thumb metacarpophalangeal (MP) joint, splitting of the extensor aponeurosis between the extensor pollicis longus and extensor pollicis brevis tendon. Opening of the anterior capsule and separation of the collateral ligaments, open up the joint, narrow concave and convex joint surface resections, adjustment of the arthrodesis position in 10-20° flexion and K­wire transfixation, dorsal plateosteosynthesis, fine adjustment of the flexion, axis and pronation position. Closure of the capsule and the periosteal gliding tissue over the plate, reconstruction of the extensor aponeurosis. POSTOPERATIVE MANAGEMENT: Splint for 3 weeks. Full load after 6-8 weeks. RESULTS: The dorsal plate arthrodesis of the thumb MP joint is a reliable surgical method with very good functional results.

[Anatomy and pathobiomechanics of the scaphoid]. / Anatomie und Pathobiomechanik des Skaphoids.

Among the carpal bones the scaphoid (Os scaphoideum) is the most important. The most frequent fracture of the carpus is a fracture of the scaphoid bone. The frequently occurring absence of healing of these fractures as well as unhealed ruptures of the ligament complex between the scaphoid and lunate, lead to the most severe biomechanical and thus the most severe clinical changes of the wrist. The detailed anatomy of the scaphoid, blood flow, ligament attachments, injury mechanisms and pathobiomechanics are described and illustrated.

[Anatomy and biomechanics of the scaphoid]. / Anatomie und Biomechanik des Kahnbeins.

The scaphoid is biomechanically and clinically of great importance for function of the wrist. In the literature, its anatomy and biomechanics are clearly underrepresented as well as underestimated. In the following review the scaphoid will be presented in more detail, according to recent information and findings. Not only will the origin of the name and the history of previous names, such as cotyloid or navicular, be introduced, but also for the first time in medical literature the significant phylogeny and ontogeny of the scaphoid will be shown. Moreover, the clinically very important blood supply, the ligaments of the scaphoid and relevant biomechanical details will be described.

Classic and non-classic progesterone receptors are both expressed in human spermatozoa.

Progesterone is one of the physiological inducers of the acrosome reaction in mammalian spermatozoa. The receptor that responds to progesterone is not yet identified, and its properties differ in many aspects from the properties of the classic nuclear progesterone receptor, suggesting the participation of a novel or non-classic receptor. In this study, we investigated the expression of a novel progesterone-binding protein (hmPR1/PGMRC1) and its ortholog (hmPR2/PGMRC2), which have previously been identified in liver microsomes and are considered receptor candidates, along with the nuclear progesterone receptor. The purification procedure was optimized with special emphasis on the control of leukocyte contamination in single donor samples. The results indicate that all three proteins are expressed in human sperm, as transcripts have been detected in 46 %, 42 % and 37.5 % of individual samples, respectively (n = 24).

Alexander disease: diagnosis with MR imaging.

BACKGROUND AND PURPOSE: To date, the demonstration of Rosenthal fibers on brain biopsy or autopsy specimens is considered a prerequisite for a definitive diagnosis of Alexander disease. We initiated a multiinstitutional survey of MR abnormalities in both presumed and confirmed cases of Alexander disease to assess the possibility of an MR-based diagnosis. METHODS: MR imaging studies in three patients with an autopsy-based diagnosis of Alexander disease were analyzed to define MR criteria for the diagnosis. These criteria were then applied to 217 children with leukoencephalopathy of unknown origin. RESULTS: Five MR imaging criteria were defined: extensive cerebral white matter changes with frontal predominance, a periventricular rim with high signal on T1-weighted images and low signal on T2-weighted images, abnormalities of basal ganglia and thalami, brain stem abnormalities, and contrast enhancement of particular gray and white matter structures. Four of the five criteria had to be met for an MR imaging-based diagnosis. In a retrospective analysis of the MR studies of the 217 patients, 19 were found who fulfilled these criteria. No other essentially new MR abnormalities were found in these patients. In four of the 19 patients, subsequent histologic confirmation was obtained. The clinical symptomatology was the same in the patients with and without histologic confirmation and correlated well with the MR abnormalities. MR abnormalities were in close agreement with the known histopathologic findings of Alexander disease. CONCLUSION: The defined criteria are sufficient for an in vivo MR imaging diagnosis of Alexander disease; only in atypical cases is a brain biopsy still necessary for a definitive diagnosis.

Dynamic nature of cavernous malformations: a prospective magnetic resonance imaging study with volumetric analysis.

OBJECT: Although cavernous malformations (CMs) are not detected in angiographic studies, they have a characteristic appearance on magnetic resonance (MR) images. A number of reports published in the last decade have focused on the behavior of these lesions within the clinical environment. However, little has been published about the evolution of CMs over time, as observed in imaging studies. To understand imaging-documented changes in CMs over time, we analyzed MR images of 114 cavernous malformations in 68 patients who were followed prospectively. METHODS: For each CM the location, volume, and MR imaging signal characteristics were recorded. Volume data were available for 107 lesions from initial images. The mean volume of these 107 CMs was 2779 mm3. The lesions ranged in size from 0.5 to 46,533 mm3 (46.5 cm3). Volume data from a second set of images were available for 76 CMs (mean interval from first imaging session 26 months), and from a third set of images for 24 lesions (mean interval from second imaging session 18 months). Over the first follow-up interval, the mean volume change was -991 mm3 (a decrease of approximately 1 cm3) and over the second interval the mean volume change was -642 mm3. Although these mean volume changes appear modest, volume changes in single lesions during follow-up intervals were more dramatic, with decreases as large as 45,629 mm3 (45.6 cm3) and increases as large as 6,074 mm3 (6 cm3). Serial examinations of the MR imaging signal characteristics of these CMs demonstrate a trend for maturation of blood products from a subacute, to a mixed, and finally to a chronic appearance. Three lesions appeared de novo during the follow-up period. CONCLUSIONS: On the basis of their analysis, the authors conclude that CMs exhibit a range of dynamic behaviors including enlargement, regression, and de novo formation, as well as progression through a series of characteristic MR imaging appearances.

A clinicopathologic reappraisal of brain stem tumor classification. Identification of pilocystic astrocytoma and fibrillary astrocytoma as distinct entities.

BACKGROUND: Brain stem tumors in children have been classified pathologically as low grade or high grade gliomas and descriptively as diffuse gliomas, intrinsic gliomas, midbrain tumors, tectal gliomas, pencil gliomas, dorsal exophytic brain stem tumors, pontine gliomas, focal medullary tumors, cervicomedullary tumors, focal gliomas, or cystic gliomas. METHODS: To search for a simplified and prognostic clinicopathologic scheme for brain stem tumors, the authors reviewed a consecutive cohort of patients younger than age 21 years with tumors diagnosed from 1980 through 1997. Pathology specimens and neuroimaging were classified by masked review. Statistical and survival analysis along with Cox proportional hazards regression was performed. RESULTS: Seventy-six patients were identified, with initial diagnostic magnetic resonance imaging available for 51 and pathology specimens for 48 patients. Twenty cases were classified histologically as pilocytic astrocytoma (PA), 14 as fibrillary astrocytoma (FA), and 14 as other tumors or indeterminate pathology. For all tumors, characteristics significantly associated with a worse survival rate were: symptom duration less than 6 months before diagnosis (P = 0.004); abducens palsy at presentation (P < 0.0001); pontine location (P = 0.0002); and engulfment of the basilar artery (P = 0.006). Pilocytic astrocytoma was associated with location outside the ventral pons (P = 0.001) and dorsal exophytic growth (P = 0.013); Fibrillary astrocytoma was associated with symptoms less than 6 months (P = 0. 006), abducens palsy (P < 0.001), and engulfment of the basilar artery (P = 0.002). Pilocytic astrocytoma showed 5-year overall survival (OS) of 95% (standard error [SE], 5%) compared with FA 1-year OS of 23% (SE, 11%;P < 0.0001). CONCLUSIONS: Brain stem tumors can be succinctly and better biologically classified as diffusely infiltrative brain stem gliomas-generally FA located in the ventral pons that present with abducens palsy, often engulf the basilar artery, and carry a grim prognosis-and focal brain stem gliomas-frequently PA arising outside the ventral pons, often with dorsal exophytic growth, a long clinical prodrome, and outstanding prognosis for survival. Our findings emphasize the individuality of PA as a distinct clinicopathologic entity with an exceptional prognosis.

Sedation procedures in MR imaging: safety, effectiveness, and nursing effect on examinations.

PURPOSE: To measure the safety and effectiveness of conscious sedation in order to assess utilization and the effect on magnetic resonance (MR) imaging examinations. MATERIALS AND METHODS: A database of conscious sedation records for MR imaging at the Johns Hopkins Hospital, Baltimore, Md, from 1991 to 1998 was searched. Safety data according to medication and procedure duration for each nurse were tabulated for 6,093 patient records. Data were analyzed by using quality control statistical measures to determine time utilization and effectiveness. Break-even costs for the procedure were determined. RESULTS: Of 6,093 patients scheduled for examination, 4,761 patients (78.1%) received conscious sedation by the MR conscious sedation service. Complications were observed in 20 of the 4,761 patients (0.42%). No deaths occurred. The most common complication was oxygen desaturation (n = 8). Diagnostic and complete MR examinations were performed in 4,453 of the 4,761 patients (93.5%). The mean time to sedate the patient (+/- SD) was 23.6 minutes +/- 15.2 for specialized MR sedation nurses and 26.8 minutes +/- 20.1 for general radiology nurses (P: <.001). For inpatient nurses from the inpatient hospital units, the sedation time was considerably longer (47.3 minutes +/- 36.6, P: <.001) and more variable. Break-even costs were 37% ($11 vs $8 for MR room time) more for general radiology nurses than for specialized MR sedation nurses performing the procedure. CONCLUSION: Conscious sedation is safe and has a high effectiveness rate. A highly specialized nursing staff reduces procedure variability and cost.

Defining and categorizing leukoencephalopathies of unknown origin: MR imaging approach.

PURPOSE: To categorize leukoencephalopathies of unknown origin into a few major groups by using magnetic resonance (MR) imaging criteria to facilitate further studies, and to assess the possibility of defining "new" (i.e., until now unknown) disease entities within these major groups. MATERIALS AND METHODS: MR images of 92 patients (55 male, 37 female; mean age, 9.3 years) with a leukoencephalopathy were examined by using a scoring list of 68 items. Seven major categories were defined according to the predominant location of the white matter abnormalities. Statistical analysis was used to assess the validity of these seven categories. RESULTS: Statistical analysis results showed that the seven categories could be well distinguished by either using the defining variables initially accepted as inclusion criteria or selecting a few other variables found to have discriminating value. The additional variables confirmed that the categories are essentially distinct and vary systematically with regard to items other than the inclusion criteria. The existence of two recently defined leukoencephalopathies was confirmed, but no consistent evidence of other new disease entities could be provided. CONCLUSION: Establishing these seven categories helps in the interpretation of individual studies by demonstrating features that the patient has in common with other patients, and it may facilitate further research on homogeneous subgroups of patients and allow pooling of data across multiple centers.

Homozygous factor-V mutation as a genetic cause of perinatal thrombosis and cerebral palsy.

A 5-year old girl with cerebral palsy (CP), preterm birth, postnatal aortic thrombus, and cerebellar venous infarction who is homozygous for the thrombophilic factor-V Leiden (fVL) mutation is reported. The role of hereditary thrombophilic disorders in the development of perinatal vascular lesions such as aortic thrombi, renal-vein thrombosis, venous-sinus thrombosis, and cerebral infarction is unknown. This case report brings into question a potential association between fVL, perinatal vascular lesions, perinatal stroke, and CP.

MRI brain changes in subjects with Down syndrome with and without dementia.

Individuals with Down syndrome (DS), a disorder of known genetic etiology (trisomy of chromosome 21), exhibit several types of structural brain abnormalities that are detectable pathologically and by MRI. In addition, in middle age, individuals with DS develop histological and, in some cases, clinical features of Alzheimer's disease (AD). Abnormalities in MRI scans of 50 adults with DS, 11 of whom had clinical dementia, are described and compared with those of 23 cognitively normal, healthy subjects who were matched for age, sex, and race. Qualitative visual analogue scale (VAS) ratings on MRI hard copies for all subjects and computer-aided volume measures for a subsample of subjects were carried out. On VAS, subjects with DS had larger lateral ventricles, a higher frequency of posterior fossa arachnoid cysts/megacisterna magna and fewer scans rated as normal compared with controls. Quantitatively, total brain and gray-matter volumes were reduced in DS, as were the volumes of the left hippocampus and amygdala; ventricle volumes were larger. Post hoc comparisons of subjects with DS with and without dementia revealed that on VAS the former had more generalized atrophy for age, mesial temporal shrinkage, and third ventricular enlargement. Similarly, total brain, left hippocampus, and left amygdala volumes were reduced quantitatively in subjects with DS with dementia, while ventricular volumes were increased.

Mesial temporal spikes interfere with working memory.

The hippocampus and other mesial temporal structures support long-term memory and also are common foci for epilepsy. Recently it was shown that these brain structures may subserve the short-term storage and rehearsal processes called working memory in humans. We determined the accuracy of verbal and visuospatial working memory in the presence and in the absence of mesial temporal spikes in eight patients who had bilateral depth electrodes implanted to evaluate intractable epilepsy. Six of eight patients had declines in working memory performance during mesial temporal spiking, with the greatest disruption in spatial and verbal recall coincident with left hippocampal spikes (p = 0.019). Overall accuracy of working memory for all patients declined an average of 6% on spike trials. The two patients who did not have decreased accuracy during spike trials also had the best overall working memory performance. Mesial temporal spikes were not detected on extracranial recordings and yet may be associated with declines in working memory in some patients with epilepsy.

Reliability and validity of MRI measurement of the amygdala and hippocampus in children with fragile X syndrome.

Evidence from numerous structural magnetic resonance imaging (MRI) studies has converged to implicate mesial temporal lobe structures in the pathophysiology of several developmental and psychiatric disorders. Efforts to integrate the results of these studies are challenged, however, by the lack of consistency, detail and precision in published protocols for the manual measurement of the amygdala and hippocampus. In this study, we describe a highly detailed, standardized protocol for measuring the amygdala and the hippocampus. Within the context of this protocol, we tested the inter- and intra-rater reliability of two frequently cited methods for normalizing the anatomical position of the amygdala and hippocampus prior to measurement. One method consisted of creating a coronal data set in which images are rotated in a plane perpendicular to the long axis of the hippocampus. The second method consisted of creating a coronal data set in which images are rotated in a plane perpendicular to the axis connecting the anterior and posterior commissures. Inter- and intra-rater reliability coefficients (using the intraclass correlation) ranged from 0.80 to 0.98, indicating that both methods for positional normalization are highly reliable. In addition, we tested the validity of each method by comparing the temporal lobe anatomy of children with fragile X syndrome to a group of unaffected children matched by age and gender. We found that hippocampal volumes in children with fragile X were significantly increased when either rotational method was used. These results replicated previous findings, suggesting that either method can be validly applied to neuronanatomic studies of pediatric populations.

Brain magnetic resonance imaging in suspected extrapyramidal cerebral palsy: observations in distinguishing genetic-metabolic from acquired causes.

Experienced clinicians recognize that some children who appear to have static cerebral palsy (CP) actually have underlying genetic-metabolic disorders. We report a series of patients with motor disorders seen in children with extrapyramidal CP in whom brain magnetic resonance imaging abnormalities provided important diagnostic clues in distinguishing genetic-metabolic disorders from other causes. One cause of static extrapyramidal CP, hypoxic-ischemic encephalopathy at the end of a term gestation, produces a characteristic pattern of hyperintense signal and atrophy in the putamen and thalamus. Other signal abnormalities and atrophy in the putamen, globus pallidus, or caudate can point to genetic-metabolic diseases, including disorders of mitochondrial and organic acid metabolism. Progress in understanding and treating genetic diseases of the developing brain makes it essential to diagnose disorders that masquerade as static CP. Brain magnetic resonance imaging is a useful diagnostic tool in the initial evaluation of children who appear to have CP.

Improved tissue characterization in adrenoleukodystrophy using magnetization transfer imaging.

OBJECTIVE: We performed this study to evaluate the usefulness of magnetization transfer (MT) imaging techniques and magnetization transfer ratio (MTR) measurements in assessing patients with adrenoleukodystrophy (ALD). SUBJECTS AND METHODS: Twelve patients who encompassed the range of ALD phenotypes were evaluated prospectively with MR and MT imaging (including digital subtraction images). The MT images and spin-echo MR images were compared by two staff neuroradiologists and a staff neurologist for extent of disease, different zones of involvement, and the presence of enhancement. MTR measurements were obtained from affected and unaffected regions of the brain. RESULTS: Eight of the 12 patients exhibited gadolinium enhancement. In seven of these patients, the MT subtraction images showed two zones of abnormal signal within the affected white matter. Their MTR measurements were classified as zone 1 (mean MTR, 35%; SD, 6%) and zone 2 (mean MTR, 20%; SD, 6%). Three of the other patients showed a single zone of involvement corresponding to the affected white matter on the standard spin-echo MR images. Their MTR measurements were similar to that of zone 1. The remaining two patients had no demonstrable signal abnormalities on any of the images. We noted no difference in any of the 12 subjects in the extent of white matter involvement on any of the imaging techniques. The MTR measurements in the unaffected white matter (mean MTR, 46%; SD, 5%) approximated established MTRs in white matter of normal volunteers. CONCLUSION: MT imaging and MTR measurements are helpful clinical techniques that may improve the evaluation of patients with ALD, particularly in the proposed ability of these techniques to divide the affected white matter into different zones that correspond to specific pathologic areas. These techniques can help the understanding of pathogenetic mechanisms and the evaluation of therapies.

Quantitative proton spectroscopy of canine brain: in vivo and in vitro correlations.

Quantitative, single-voxel proton NMR spectroscopy of normal brain was performed in five adult beagle dogs using the cerebral water signal as an internal intensity reference. The same brain regions were then rapidly isolated and frozen using a pneumatic biopsy drill, perchloric acid extracted, and analyzed by biochemical assay and high-resolution NMR spectroscopy. The concentrations of the major resonances in the in vivo and in vitro spectra were compared, and good agreement was found between the different measurements. The in vivo spectra contained three peaks at 3.21, 3.04, and 2.02 ppm, which are usually assigned to trimethylamines (TMA), creatines, and N-acetyl derivatives (NAc), which corresponded to be the following metabolite concentration values: 1.7 +/- 0.6, 7.7 +/- 2.1, and 10.9 +/- 2.7 mumol/g wet weight respectively. In vitro, the following metabolite concentrations were measured: glycerophosphocholine (GPC) 1.3 +/- 0.2, phosphocholine (PC) 0.5 +/- 0.1, phosphocreatine (PCr) 2.6 +/- 0.4, creatine (Cr) 5.9 +/- 1.4, and N-Acetyl aspartate (NAA) 8.9 +/- 1.8 mumol/g wet weight. Therefore, the 3.21 ppm resonance observed in the in vivo spectrum is predominantly GPC and PC in a ratio of 2.6:1, the 3.04 ppm resonance is Cr and PCr in a ratio of 2.3:1, and the 2.02 ppm resonance is predominantly (approximately 80%) NAA with small contributions from N-acetylaspartylglutamate (NAAG) and glutamate. The data presented here validate the technique of water referencing as a simple and convenient means of quantitating single-voxel in vivo proton NMR spectra of the brain.

Proton MR spectroscopy in patients with seizure disorders.

PURPOSE: To evaluate the ability of proton MR spectroscopy to detect metabolic abnormalities in the seizure focus of humans with epilepsy. METHODS: Single-voxel MR spectroscopy and MR imaging was performed in a group of 13 patients with a variety of seizure disorders and in the temporal lobes of 14 healthy volunteers. Signals from choline, creatine, N-acetyl-L-aspartate, and lactate were quantitated in both the epileptogenic focus and the contralateral brain region. RESULTS: In normal temporal lobe, concentrations of choline, creatine, and N-acetyl-L-aspartate were 2.0 +/- 0.7, 7.8 +/- 1.9, and 11.0 +/- 2.1 mumol/g wet weight, respectively, with no detectable lactate. In all patients, a reduction in the N-acetyl-L-aspartate signal was observed in the electrically defined (scalp electroencephalogram) seizure focus compared with the mirror-image contralateral side. Lactate was elevated only in patients who had seizures during or immediately before the MR examination. Seven of 13 patients studied had normal MR examinations. CONCLUSIONS: Proton spectroscopy demonstrates alterations in N-acetyl-L-aspartate and lactate levels that can be used to locate the epileptogenic focus and may be a useful adjunctive diagnostic technique for the evaluation of patients with seizures who are eligible for resective surgery.