The diagnosis of infections of the spine by modern imaging techniques.

MR image scanning is the most sensitive and specific imaging modality to diagnose infection of the spine. The infected disc and adjacent vertebral end plates will show increased water signal owing to the infection. The diagnosis of infection of the spine and the differentiation between infection and lesions simulating infection is described.

High-resolution computerized tomography and nuclear bone scanning in the diagnosis of postoperative stress fractures of the mandible: a clinical report.

Root-form titanium dental implants are the treatment of choice for many partially and totally edentulous patients. The overall success rate is greater than 95%. Postoperative pain is usually the result of infection. This report presents two cases involving a sudden onset of jaw pain. Computerized tomographic scanning revealed that the pain was caused by stress fracture of the mandible.

Spinal disease in the aged.

Treatment of the diseased spine in the elderly is a difficult challenge for the practitioner. Spinal surgery for this population requires specialized surgical skills. Patient evaluation, nonoperative treatment, surgical indications, surgical techniques, and postoperative management involve unique considerations. The patient's functional expectations, general medical condition, and proposed benefits from surgery must be addressed before any surgical intervention. Spinal surgery for the aged requires the orthopaedic surgeon to consider this patient as more than just an older individual and demands that the entire perioperative milieu be examined and its issues resolved. The projected data on aging of the United States population make this issue increasingly important.

Computed tomography in dental implantation surgery.

High-resolution thin section CT with cross-sectional oblique and panoramic CT reconstructions has been shown to be an excellent tool for the preoperative evaluation of the mandible and maxilla for dental implant surgery. Oblique cross-sections throughout the entire surgical field allow visualization of osseous topography as well as related internal anatomic structures such as the inferior alveolar canal, the mental foramina, the incisive canal, and the maxillary sinuses. Armed with this knowledge, the surgeon-restorative dentist team can plan fixture positioning more effectively, thereby minimizing surprises in the operating room. Cases with inadequate buccolingual bone dimension are not attempted, whereas many other cases that do not appear to have adequate bone, as seen on conventional x-ray films, can be successfully implanted. The ultimate prosthesis is optimized because the surgeon can take full advantage of the available bone to achieve proper fixture alignment. It is quite likely that as future experience is obtained with maxillofacial CT, it may also be useful in diagnosis and treatment for a wide variety of other disorders of the jaw.

Anatomic analysis of pedicle cortical and cancellous diameter as related to screw size.

The effective thoracic and lumbar pedicle diameter as related to screw size for that pedicle was studied in six fresh-frozen human cadaver spines. Measurements of the pedicle were obtained before screw insertion using axial and coronal reformatted computed tomographic (CT) images, as well as graduated sounding of the pedicle. After sequentially loading each pedicle with increasingly larger screws, measurements were taken of the outer cortical diameters. Plastic deformation of the pedicle preceded pedicle fracture or cutout when the screw thread diameter became larger than the endosteal diameter or within 80% of the outer cortical diameter as measured from the CT scan. Pedicle screws did not obtain cortical purchase within the pedicle.

CT in the preoperative assessment of the mandible and maxilla for endosseous implant surgery. Work in progress.

A new computer software program that generates panoramic and oblique computed tomography scans was used to examine 205 patients who were being considered for endosseous dental implants in the mandibular or maxillary arches. This technique allowed recognition of the course of the inferior alveolar nerve canal and measurement of the alveolar ridge, which facilitated the design and placement of an optimal dental prosthesis.

Analysis of the morphometric characteristics of the thoracic and lumbar pedicles.

A total of 2,905 pedicle measurements were made from T1-L5. Measurements were made from spinal computerized tomography (CT) scan examinations and individual vertebral specimen roentgenograms. Parameters considered were the pedicle isthmus width in the transverse and sagittal planes, pedicle angles in the transverse and sagittal planes, and the depth to the anterior cortex in a line parallel to the midline of the vertebral body and along the pedicle axis. There was no significant difference between data obtained from CT scans and specimen roentgenograms. Pedicles were widest at L5 and narrowest at T5 in the transverse plane. The widest pedicles in the sagittal plane were seen at T11, the narrowest at T1. Due to the oval shape of the pedicle, the sagittal plane width was generally larger than the transverse plane width. The largest pedicle angle in the transverse plane was at L5. The posterolateral to anterolateral pedicle axis orientation in the transverse plane, seen at other levels throughout the thoracolumbar spine, reversed at T12. In the sagittal plane, the pedicles angled caudally at L5 and cephaladly from L3-T1. The depth to the anterior cortex was significantly longer along the pedicle axis than along a line parallel to the midline of the vertebral body at all levels with the exception of T12 and T11.

Computed tomography of the spine in older children and teenagers.

In this short discussion, I have attempted to demonstrate the usefulness of reformatted thin-section spine CT in the evaluation of back syndromes in older children. It is most important to realize that subtle diagnosis requires strict attention to technical detail in performing CT scans, as well as sophistication in computer software to make easily understandable pictures. Axial images alone are totally inadequate for diagnosing some of the abnormalities presented herein. Several of the entities included in this article have never been described by any other radiographic examination, to my knowledge. I believe that reformatted thin-section CT is the single most important radiographic examination of the spine.

Postoperative fractures of lumbar articular facets: occult cause of radiculopathy.

Fracture of the inferior lumbar articular facets after laminectomy with facetectomy is a relatively common but unrecognized cause of radiculopathy. Although not all patients may be symptomatic from the fractures, some may have radiculopathy or back pain caused by displacement of the fracture fragment. In a series of 400 postoperative spinal computed tomographic (CT) scans, 25 patients were found who had fractures through the base of the inferior facets. Axial scans revealed no abnormality other than slight widening of the joint on the affected side. Sagittal views demonstrated a lucent defect similar to a pars interarticularis fracture, whereas coronal views showed the fracture at a different location in the base of the facet. Typically patients become symptomatic after a period of postsurgical well-being. A new pain pattern, local tenderness, pain on unusual movements, and relief with recumbency help suggest facet fracture versus recurrent disk herniation.

Multiplanar CT in the evaluation of degenerative spondylolisthesis. A review of 150 cases.

Degenerative spondylolisthesis (pseudospondylolisthesis) is a degenerative disorder of the intervertebral motion segment. It can be divided into two types: forward subluxation and backward subluxation. Forward subluxation is primarily a disease of the posterior joints and is found most commonly at L4/5. Retrolisthesis is a primary disorder of the disc space and is noted more commonly at L3/4. This paper reviews the CT findings in 150 patients with degenerative forward and backward subluxation. Proper evaluation of these disorders is extremely important because of the frequency of severe symptomatic spinal stenosis or foraminal encroachment.

Computed tomographic brain scanning in four neuropsychiatric disorders of childhood.

CAT scans were performed in 66 patients with neuropsychiatric disorders of childhood (infantile autism, attention deficit disorder, Tourette's disorder, and language disorder) and a control group of 20 medical patients. Ventricular volume and brain density were determined by quantitative, computer-based methods by researchers blind to the patients' diagnoses. There were no significant differences among diagnostic groups or between neuropsychiatric patients and medical control patients in total ventricular volume, right-left ventricular volume ratio, ventricular asymmetries, ventricle-brain ratios, or brain density.

CT evaluation of interbody fusion.

Reformatted computed tomography (CT) of the spine is very useful in the evaluation of patients who have previously been treated by lumbar or cervical interbody fusions. It allows incontrovertible evidence of failure of osseous fusion as well as defines the major causes of residual or recurrent symptoms. As CT methodology becomes a routine procedure, it will be the primary diagnostic aid in evaluating postoperative posterior lumbar interbody fusion (PLIF) patients.

Behavioral correlates of computed tomographic (CT) scan changes in older psychiatric patients.

Fifty psychiatric inpatients aged 50 and over, with no hard neurologic findings, and with a variety of DSM-III diagnoses (adjustment disorder, affective illness, and dementia), were rated for behavioral and psychiatric symptoms using the Geriatric Rating Scale and the Nurse's Assessment of Global Symptomatology-Elderly. These clinical ratings were correlated with computed tomographic (CT) scan assessments of various superficial cerebral regions as well as with linear measures of ventricular size. Behavioral deficits in activities of daily living (ADL) plus an interactional variable, inability to respond to requests, were correlated with superior temporal and inferior parietal CT abnormalities, particularly on the left side. Suspiciousness and peculiar thinking, mood lability and irritability, as well as impaired memory with confusion, perplexity, and disorientation were also associated with atrophy in these same regions. Prefrontal area defects correlated with mood lability and deficits in visual-interactional responsiveness. Statistically controlling for effects of age and alcohol abuse did not alter the basic nature of these results. Regional cerebral specialization in relation to these results are discussed using concepts developed by Luria.

Computed tomography of the spine: curved coronal reformations from serial images.

A new imaging format described here uses nonplanar reformations that follow the contour of curved structures intersected by a series of regularly spaced CT scans. The CT scanning procedure is described, and algorithmic details of this new format are presented. A standard set of reformatted images is suggested, and clinical examples are given to illustrate the diagnostic value of this new format.