CT of blunt trauma bowel and mesenteric injury: typical findings and pitfalls in diagnosis.

Detection of bowel and mesenteric injury can be challenging in patients after blunt abdominal trauma. Early diagnosis and treatment are critical to decrease patient morbidity and mortality. Computed tomography (CT) has become the primary modality for the imaging of these patients. Signs of bowel perforation such as free air and contrast material are virtually pathognomonic. Bowel-wall thickening, free fluid, and mesenteric infiltration may be seen with this type of injury and partial thickness injuries. The authors present and discuss the range of CT findings seen with bowel and mesenteric injuries. Examples of observation and interpretation errors are also provided to highlight pitfalls encountered in the evaluation of abdominopelvic CT scans in patients after blunt trauma.

Evaluation of pulmonary emboli: current concepts.

While radionuclide lung V/Q scanning remains the standard initial pulmonary imaging test in suspected pulmonary emboli, other modalities may be useful, particularly in those patients with intermediate probability V/Q scans. Compression US of the lower extremities, spiral CT angiography, and conventional pulmonary anteriography may help to establish the diagnosis of pulmonary embolism.

Thoracic carcinoids: radiologic-pathologic correlation.

Carcinoids are neuroendocrine neoplasms. Bronchial carcinoids are unusual, malignant primary neoplasms that characteristically involve the central airways and typically exhibit well-defined margins and bronchial-related growth. Bronchial carcinoids include low-grade typical carcinoids and the more aggressive atypical carcinoids. These tumors usually affect patients in the 3rd through 7th decades of life who are often symptomatic with cough, hemoptysis, or obstructive pneumonia. Bronchial carcinoids radiologically manifest as hilar or perihilar masses, with or without associated atelectasis, pneumonia, bronchiectasis, or mucoid impaction. At computed tomography, an anatomic relationship of these tumors to a bronchus is usually seen, and they may show contrast material enhancement or calcification. In rare cases, carcinoids occur in the thymus; when they do, they are aggressive tumors that affect adults who usually present with chest pain, cough, and dyspnea. Thymic carcinoids manifest radiologically as anterior mediastinal masses and may mimic thymomas. Thoracic carcinoids are treated by surgical excision. The prognosis for patients with typical bronchial carcinoids is excellent; patients with atypical bronchial or thymic carcinoids have a worse prognosis.

Combined clinical and computed tomographic diagnosis of primary lacrimal fossa lesions.

We studied 39 patients who had solid mass-lesions primary in the lacrimal gland by computed tomography and reviewed their clinical histories. Twenty-three patients had either inflammatory conditions (16 cases) or lymphoid tumors (seven cases), with average symptomatic periods of less than a year. In this group, soft-tissue contour analysis in the axial and corneal projections demonstrated diffuse, compressed, and molded enlargements of the lacrimal gland in an oblong fashion, and there were no associated bone defects. Sixteen parenchymal benign or malignant tumors (six benign mixed tumors, one schwannoma, and nine malignant epithelial tumors) exhibited rounded or globular soft-tissue outlines and were frequently associated with contiguous bone changes. The benign tumors had smooth encapsulated outlines at their margins, whereas the malignant tumors displayed microserrations indicative of infiltration. The patients with the benign mixed tumors had had symptoms, on the average, for more than a year, whereas those with epithelial malignancies became symptomatic or had a preexisting benign mixed tumor that became exacerbated in periods of less than six months. Contour analysis of the soft-tissue mass depicted in coronal and axial tomograms is a valuable adjunct that leads to more accurate preoperative diagnosis when combined with a radiographic search for bone changes and the clinical history. Once a diagnosis regarding the presumptive lesional family has been made preoperatively, corticosteroid therapy may be instituted for acute inflammation and biopsies through the eyelid should be performed for suspected chronic inflammations, lymphoid lesions, or epithelial malignancies. A lateral orbitotomy without prior biopsy should be performed for rounded, well-encapsulated masses of long duration that are likely to be benign mixed tumors.

Combined clinical and computed tomographic diagnosis of orbital lymphoid tumors.

Computed tomography has made it possible to make a strongly presumptive preoperative diagnosis of orbital lymphoid tumors, particularly when the radiographic findings are analyzed in conjunction with the clinical features. Twenty-six patients (with 27 orbital lymphoid tumors) had an average age of 57 years and had painless swelling or low-grade proptosis averaging 7.5 months in duration. The computed tomographic findings were highly characteristic. Almost all of the tumors had a retrobulbar or superior orbital component. In both the coronal and axial planes, distinctive growth patterns and contourings were discovered. The lesions molded themselves to preexisting orbital structures without eroding bone or enlarging the orbit. Against the bone, globe, and muscle edges, the lesions featured smooth, sharply demarcated contours with abruptly acute or perpendicular angulations, whereas a streaky profile became apparent as they irregularly infiltrated the retrobulbar fat, reflecting involvement of microfascial structural elements. No distinguishing differences were discovered in the growth patterns of the benign and the malignant tumors.

CT of the lumbosacral spine: importance of tomographic planes parallel to vertebral end plate.

An experimental computer program capable of reformatting stored display data from a CT scanner into true cross-sectional images of the spine has been clinically tested over a 1 year period. With this program, tomographic planes exactly parallel to the vertebral end plate can be imaged at the lumbosacral level even in patients who are markedly rotated or have scoliotic deformities. The reformatted image planes are tilted in the dorsoventral and mediolateral directions to compensate for lordosis or scoliosis. The reformatting can also produce images in coronal and sagittal planes on axes other than true horizontal or vertical. The program has been used in the examination of 269 spines and has been found to be valuable in demonstrating the spinal canal and the intervertebral foramina.

National Cancer Institute study: evaluation of computed tomography in the diagnosis of intracranial neoplasms. III. Metastatic tumors.

Intracranial metastases were detected in 343 patients in the National Cancer Institute study of computed tomography (CT) in the diagnosis of intracranial tumors. The metastatic lesions were divided into five groups according to the organ of origin. Studies of the attenuation values of the brain lesions showed no distinctive features that would enable the identification of the site of the primary lesion. The sensitivity of CT and angiography was superior to that of radionuclide scanning. Brain metastases showed CT densities less than, equal to, or greater than the normal brain, with attenuation values ranging up to 40. They were found most frequently in the frontal region, and approximately 90% of the lesions showed necrosis. Surrounding edema was usually moderate or marked.

Informational molecules in amoebae studies of template utilization by the DNA polymerase activities of Amoeba discoides.

Studies have shown that certain strain-specific characters of large, free-living amoebae may be influenced by the microinjection of non-homologous low molecular weight RNAs. To investigate the mechanisms involved in 'information' transfer, the template preferences of partially purified DNA polymerase activities isolated from Amoeba discoides have been studied. After passage through Sephadex G-200, DNA polymerase activities from whole homogenates could utilize both 'activated' calf thymus DNA and the synthetic ribohomopolymer poly rA oligo d(pT)10 as templates. Fractionation using different saturations of (NH4)2SO4 showed that there was no detectable poly A d(pT)10-directed DNA polymerase activity in the extra-mitochondrial cytoplasm, and the ability to utilize this template appeared to be located in the nuclei. Nuclear protein passed through short (30 cm) columns of Sephadex G-200 showed DNA polymerase activities which could use both synthetic and natural RNA as templates, but little activity was detected when using longer (70 cm) columns, although DNA-directed DNA polymerase activities were more clearly defined. Use of DEAE-cellulose only revealed a low (1--3%) activity with poly A d(pT)10 compared to the activity observed using 'activated' calf thymus DNS. DNA polymerase activities of amoebae showed a response to added RNA templates which depended on the purity of the enzyme preparation, and the possibility that these enzymes are involved in 'information' transfer cannot be ruled out.

Absence of low molecular weight DNA polymerase activity from the nuclei of Amoeba discoides.

Amoeba discoides nuclear protein partially purified by passage through Sephadex G-200 showed 3 high-mol.-wt. DNA polymerase activities which eluted in and just following the void volume. No low-mol.-wt (45,000 daltons) DNA polymerase beta activity was detected. Nuclear protein layered on 5--20% sucrose gradients also showed an absence of low-mol.-wt DNA polymerase beta. The void volume enzyme showed deoxyribonuclease activity, but no low-mol.-wt nuclease activity was detected.

Duodenal intussusception secondary to Brunner's gland hamartoma. A case report.

Intussusception of the duodenum is a relatively rare event, and usually results from the presence of benign tumors. A case of duodenal intussusception secondary to Brunner's gland hamartoma is described and its differential diagnosis discussed.

Possible causes of complications of myelography with water-soluble contrast medium.

The mechanisms of CSF formation and absorption have been reviewed. The conditions that alter the rate of CSF formation and absorption may change the concentration of contrast in the cranial cisterns and the rate of passage through the cisterns. The significance of these alterations in relation to the complications of myelography with water-soluble contrast media is discussed.

Fungal aneurysms of intracranial vessels.

Intracranial fungal aneurysms arise from major cerebral arteries. Fungi directly invade vessel walls from the luminal surface (fungal emboli) or from the adventitia (fungal meningitis). The vasa vasorum are free of fungi. Aneurysmal rupture is common with extensive hemorrhagic necrosis of the surrounding brain. Aspergillus is the usual causative agent; its sources are nasal sinusitis or endocarditis.