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At least 667 records · Page 37Linked to original sources
PubMed1976

Computed tomography in the diagnosis of extra-axial posterior fossa masses.

Extra-axial posterior fossa masses can be diagnosed reliably by computed tomography (CT) in most cases. Acoustic and trigeminal neurinomas, meningiomas, cholesteatomas, and other extra-axial masses can usually be distinguished from intra-axial masses by asymmetric widening of the basal subarachnoid spaces, bone destruction, continuity of the tumor mass with the tentorium or bone, and more sharply defined margins. Multiple-cut study of the posterior fossa improved visualization of the fourth ventricle and basal cisterns. Interpretation of cisternal changes in association with changes in the fourth ventricle and abnormal attenuation coefficients permits accurate diagnosis of posterior fossa masses.

Aneurysm↗
PubMed1977

Autotomography: a means of improving visualization of the upper cervical spine.

Autotomography permits improved visualization of the atlas-axis and occipito-cervical articulations with virtually any x-ray equipment in less time than is required for anteroposterior and lateral tomograms. This technique is best applied in nontraumatic cases in which the dens is not seen clearly on the "open mouth view".

Axis, Cervical Vertebra↗
PubMed1978

Reiter disease with atlanto-axial subluxation.

The authors report the first known case of atlanto-axial subluxation in Reiter arthritis. The type of analysis, including radiographic and laboratory examinations, required for a diagnosis of atypical Reiter disease is an important feature of the case.

Adult↗
PubMed1994

Craniovertebral junction: normal anatomy, craniometry, and congenital anomalies.

The craniovertebral junction (CVJ) comprises the occiput, atlas, and axis and is visible in most magnetic resonance (MR) imaging studies of the brain. Craniometric measurements used in radiologic assessment of CVJ anomalies include the Chamberlain line, Wackenheim clivus baseline, Welcher basal angle, and atlantooccipital joint axis angle. Most anomalies of the occiput are associated with decreased skull base height and basilar invagination, the latter being a primary developmental anomaly in which the vertebral column is abnormally high and prolapsed into the skull base. Occiput anomalies include condylus tertius, condylar hypoplasia, basiocciput hypoplasia, and atlanto-occipital assimilation. Most atlas anomalies produce no abnormal CVJ relationships and are not associated with basilar invagination. These anomalies include aplasias, hypoplasias, and clefts of the atlas arches and "split atlas" (ie, posterior arch rachischisis associated with anterior arch rachischisis). Except for fusion anomalies, abnormalities of the axis are primarily confined to the odontoid process and are not associated with basilar invagination. These anomalies include persistent ossiculum terminale, odontoid aplasia, and os odontoideum. With the widespread availability of MR imaging, which is well suited for evaluating the CVJ because of its direct sagittal imaging capabilities, renewed understanding of CVJ anatomy and anomalies is important for all radiologists.

Adolescent↗
PubMed1982

Prognostic features of atlantoaxial subluxation in rheumatoid arthritis patients.

The clinical and radiographic findings of 194 patients with rheumatoid arthritis and atlantoaxial (C1-C2) subluxation and/or atlantoaxial impaction (AAI) were reviewed. The condition of most patients with C1-C2 alignment abnormalities remained unchanged or became worse with time (i.e., the misalignment became fixed, subluxation increased, or AAI developed). The chance of developing upper cervical cord compression was not related to worsening per se, but to the degree of deformity. Upper spinal cord compression developed more often in men; when C1-C2 subluxation was greater than 9 mm; and in the presence of atlantoaxial impaction. The presence of lateral C1-C2 subluxation probably also contributes to the development of upper spinal cord compression. Settling of the skull and C1 onto C2 (AAI) were considered to be present when the anterior arch of C1 was abnormally low in relation to C2.

Adult↗
PubMed1984

Low (type III) odontoid fracture: a new radiographic sign.

Dens fractures are frequently difficult to identify radiographically, particularly when it is only possible to obtain a lateral radiograph of the upper cervical spine. Further, when a dens fracture is identified in lateral projection, it is often difficult to distinguish the "high" (Type II) from the "low" (Type III) fracture. The authors describe an elongated "ring" density superimposed upon the body of the axis in the lateral cervical radiograph which, when horizontally disrupted, indicates a dens fracture and is a specific radiographic sign of the "low" variety.

Axis, Cervical Vertebra↗
PubMed1987

Hangman's fracture: radiologic assessment in 27 cases.

Traumatic spondylolisthesis of C-2, frequently referred to as the hangman's fracture, is typically regarded as a hyperextension injury with rare neurologic sequelae by virtue of decompression of the neural canal. The authors retrospectively evaluated their radiographic experience with this injury in 27 patients over a 24-month period. Lateral cervical spine studies and computed tomography (CT) scans (21 patients) were analyzed. CT studies provided better delineation of the fracture in all 21 patients and significant additional information in five patients (24%). Seven patients (26%) suffered initial neurologic sequelae in association with the C-2 injury. Nine patients had additional sites of fracture, including seven with associated C-1 ring disruption (26%). Extension of the fracture line into the transverse vertebral artery foramen led to vertebral artery injury and cerebellar embolization in one patient. Angiography may be necessary to detect intimal injury to the vertebral arteries when the fracture extends through the transverse foramina and to indicate the need for anticoagulation when clinically feasible.

Adolescent↗
PubMed1989

Hypertrophy of C-1 anterior arch: useful sign to distinguish os odontoideum from acute dens fracture.

Dens fractures are often difficult to detect radiographically because of overlapping structures. The lateral radiographs were examined of all patients at the authors' institution who demonstrated an abnormal odontoid process or an abnormal anterior arch of C-1. Six patients were found: Four had os odontoideum, one had rheumatoid arthritis, and one had a congenital defect in the posterior arch of C-1. All had hypertrophy of the C-1 anterior arch on the lateral view. The width of the anterior arch of C-1 and the cortical thickness of the anterior arch in these six patients were measured and compared with the findings in a control group of 20 patients; the measurements from the six patients were found to be significantly greater. Hypertrophy of the anterior arch of C-1 is a useful sign of a chronic pathologic condition at the atlantoaxial articulation, and in the setting of acute trauma it may be an important clue that prevents unnecessary invasive treatment for a mistaken diagnosis of fractured dens.

Acute Disease↗