Coronal computed tomography

The authors describe a method of direct coronal computed tomography (CT) of the body for infants and children who are introduced onto the gantry in a lateral decubitus position transversely across the examination table. Scans are planned from a lateral scout view, with the number of coronal scans ranging from four to six. Images are more informative and detail is sharper than routine axial cuts with coronal reformations. This method is valuable in resolving complex problems related to disease adjacent to the diaphragm and can accurately demonstrate the extension and relation of lesions to neighboring structures.     

Appearance of Graves' disease on orbital computed tomography

Extraocular muscle enlargement was symmetrical in 70% and asymmetrical in 30% of patients with Graves' ophthalmopathy. True unilateral muscle involvement occurred in 6%. Computed tomography (CT) showed bilateral orbital involvement in 50% of patients presenting clinically with unilateral eye signs. In patients without a clinically apparent ophthalmopathy, CT demonstrated muscle enlargement in 40%. The medial and inferior rectus muscles were the most frequently and most severely involved. Orbital radiation therapy can result in a decrease in size of involved muscles.     

High resolution orbital computed tomography

The latest generation CT scanners allow for spatial and contrast resolution within the orbit that has not previously been available. Utilization of these technological advances in association with appropriate techniques enables visualization of vascular and neural structures within the orbits that have not previously been emphasized in the literature. The CT scans were generated in both axial and coronal planes, using either 1 or 2 mm thick sections. All images were generated using ultrahigh resolution scanning techniques, available on the Picker 1200-SX scanner. The primary advantage of this system is the availability of secondary collimation of the X-ray beam at the detector, limiting detector aperture to only 1.3 mm. This, in association with utilization of the small focal spot and high sampling rate, aids in the visualization of divisions of the third and fifth nerves, as well as in the visualization of the sixth nerve within the orbit. Several branches of the ophthalmic artery within the orbit are also identified, including the infratrochlear and supratrochlear artery as well as the central retinal artery.     

Coronal computed tomography: indications and accuracy.

The application of wide aperture scanners to neuroradiology permits improved anatomic definition and localization of intracranial and intraorbital lesions. Coronal scans are most useful in demonstrating lesions of the skull base and apex, distinguishing between infra- and supratentorial lesions, and in determining if a lesion is intra- or extraaxial. Limitations of coronal scans include discomfort in positioning, high spatial frequency artifacts, and additional radiation exposure.     

Coronal head scans by computed tomography with patient in sitting position

Coronal scans of any region of the head as well as of the craniocervical region may be obtained with the patient in sitting position. The Hitachi tomograph is used for this purpose.     

Atypical computed tomography findings in a case of orbital pseudotumor

The computer tomographic manifestations of orbital pseudotumors are varied. Among these findings, tram-tracking of the optic nerve sheath complex is rare. A patient with this unusual scan appearance is presented. Despite rapid clinical response to steroid therapy, this patient showed little initial improvement on computed tomography. The use of computed tomography scanning in the management of orbital pseudotumor is discussed.     

Abdominal computed tomography in Whipple's disease

The computed tomographic findings in a patient with Whipple's disease are described. Particular emphasis is placed on the extraintestinal manifestations of lymphadenopathy, which are not as familiar to radiologists and have been difficult to demonstrate with conventional radiographic techniques.     

Histographic studies in computed tomography of contrast-enhanced cerebral and orbital tumors

The density distribution inside a pathologic zone before and after contrast enhancement has been studied in the computed tomograms of 88 cases of cerebral and orbital tumors, using histographic analysis. The histograms provided additional diagnostic information, especially for vascular tumors. This method is also useful for experimentation with contrast media.     

螺旋CT容积测量在眼眶发育中的应用

目的:探讨正常眼眶容积的发育规律。方法:应用螺旋CT(SCT)扫描及重建技术测量12 3例正常眼眶容积,分析其与年龄、性别、内眶距的关系,并观察2 1例筛窦炎患者与正常人的眼眶容积的差异。结果:14岁前眼眶容积增长迅速,正常成人眼眶容积男性大于女性,平均眼眶容积男女分别为2 5 .0 4±2 .37ml,2 2 .89±2 .6 7ml。眼眶容积与内眶距无相关,筛窦炎患者与正常人的眼眶容积差异无显著性意义。结论:SCT可用于眼眶容积的测量,眼眶容积呈随年龄增长而增大的趋势     

Measurement of orbital volumes following trauma using low-dose computed tomography

We describe a simple CT technique for the assessment of enophthalmos and measurement of orbital volumes following trauma. The technique uses original diagnostic CT images, standard CT software and involves no additional radiation dose or scan time. The results of this technique in 66 patients with orbital trauma are presented. The incidence of post-traumatic enophthalmos was significantly raised in association with combined blow-out fractures of the floor and medial wall of the orbit and where orbital blow-out fractures occurred in conjunction with zygomatic injury. Patients without bony imjury had a traumatised orbit volume less than 1 cm³ greater than the non-traumatised side in all cases. Intra-observer reproducibility of the measurement of difference in volume between traumatised and non-traumatised orbit was ± 0.3 cm³ (1 SD). In patients with fracture, increase in orbital volume by more than 2 cm³ compared with the contralateral orbit was strongly associated with enophthalmos (sensitivity 100%, positive predictive value 69%). We conclude that routine volumetric assessment following orbital trauma provides a clinically useful, objective assessment of the risk of post-traumatic enophthalmos and that an increase in orbital volume greater than 2 cm³ is an indication for surgical repair.Correspondence to: R. W. Whitehouse     

Serial computed tomography findings in Creutzfeldt-Jakob disease

Summary Serial CT investigations of 3 patients with histologically confirmed Creutzfeldt-Jakob disease revealed persisting slight brain atrophy to progressive extreme atrophy corresponding to the absolute, not the individual duration of illness. No correlation was observed between CT findings and the patients' condition or electroencephalographic results. In one case with a duration of about 16 months and a terminal brain weight of 750 g a massive bilateral, later unilateral subdural hygroma appeared which probabely was caused by retraction of the brain showing an enormous atrophy.     

High-resolution computed tomography of temporal bone: Part IV: Coronal postoperative anatomy

The purpose of this 4-part series is to illustrate the nuances of temporal bone anatomy using a high-resolution (200 micro isotropic) prototype volume computed tomography (CT) scanner. The normal anatomy in axial and coronal sections is depicted in the first and second parts. In this, the fourth part, and the third part, the structures that are removed and/or altered in 9 different surgical procedures are color coded and inscribed in the same coronal (article IV) and axial (article III) sections. The text stresses clinically important imaging features, including the normal postoperative appearance, and common complications after these operations. The superior resolution of the volume CT images is vital to the comprehensive and accurate representation of these operations. Minuscule intricate structures that are currently only localized in the mind's eye because of the resolution limit of conventional CT are clearly seen on these scans. This enhanced visualization, together with the information presented in the text, should assist in interpreting temporal bone scans, communicating with surgeons, and teaching this complex anatomy.     

Minamata disease demonstrated by computed tomography

Summary Computed tomography was studied in the patients with Minamata disease, a methylmercury poisoning caused by the ingestion of contaminated sea foods. The characteristic changes in the acquired cases were atrophy of the visual calcarine cortex and of the cerebellar vermis and/or hemisphere. Marked atrophy of the calcarine cortex produced the sac-shaped low density areas between the occipital lobes and diffuse and marked cerebellar atrophy with enlargement of the fourth ventricle and cisterns of the posterior fossa produced a shrunken image on CT. Morphometric analysis confirmed these findings. In the fetal cases, the changes on CT were slight and no definite atrophy was demonstrated in either the calcarine cortex or the cerebellum. Morphometric analysis disclosed an increase of size of the middle portions of the lateral ventricle and the third and fourth ventricles.This work was supported by research grants from the Environment Agency and the Government of Kumamoto Prefecture, Japan     

Detection of orbital foreign bodies with computed tomography: current limits

Detection and localization of known orbital foreign bodies with computed tomography was evaluated using a model that simulates as closely as possible in vivo conditions. The GE 8800 scanner proved to be an excellent instrument for detection and localization of most orbital or intraocular foreign bodies above certain minimum levels of detectability. The minimum detectable size varied according to the material, for example, 0.06 mm3 for steel, 1.82 mm3 for auto window glass in intraocular position, and slightly larger size for extraocular location. Small wood fragments were not detected.     

Single photon emission computed tomography and transmission computed tomography in the evaluation of liver disease

To assess the relative strengths of hepatic SPECT and transmission computed tomography (TCT), a comparison of these methods was made in 88 patients during a 20-month period. The scans were classified into four categories: normal, solitary focal, multifocal, or diffuse hepatocellular patterns. The final disease category was determined by histologic evaluation-biopsy/autopsy, surgery, or a combination of ultrasound, laboratory, and clinical follow-up for a minimum of 6 months. Both SPECT and TCT were normal in the 47 patients classified as normal. Of the 16 patients with diffuse hepatocellular disease, SPECT correctly identified 16 and TCT identified two patients. Eleven patients had solitary focal disease; 11 were detected by SPECT and 10 by TCT. Fourteen patients were in the multifocal disease group; 13 were detected by SPECT and 10 by TCT. Overall, SPECT and TCT findings were in agreement in 68 (77%) of the cases. This study demonstrates that SPECT is equal to TCT in the assessment of the liver parenchyma in normal and focal disease states and that SPECT is superior in the assessment of diffuse disease.