Table Increment Research Articles

Computed Tomographic Arteriography of the Liver Using Balloon Occlusion

The article describes a new method for computed tomographic arteriography (CTA) of hepatocellular carcinoma (HCC) using a balloon occlusion catheter in 8 patients. Our dynamic study indicated that: 1) a bolus injection of contrast medium with our method of CTA (CTA-B) produced an attenuation difference between liver and tumor which was about double that obtained with standard methods for CTA, and 2) marked tumor-liver attenuation differences (above 20 HU) persisted for more than 60 s in CTA-B and for not more than 20 s with conventional methods for CTA. The results show that CTA-B is superior to standard methods in enabling multiple scans of the liver during greater and prolonged differential tumor enhancement after administration of a bolus of contrast medium. In conjunction with table incrementation, CTA-B allows scanning of the entire liver at the time of maximal contrast enhancement with two to three injections of contrast medium. Two patients complained of abdominal pain during balloon inflation. No other complications were observed.

Computed Tomographic Arteriography of the Liver Using Balloon Occlusion

The article describes a new method for computed tomographic arteriography (CTA) of hepatocellular carcinoma (HCC) using a balloon occlusion catheter in 8 patients. Our dynamic study indicated that: 1) a bolus injection of contrast medium with our method of CTA (CTA-B) produced an attenuation difference between liver and tumor which was about double that obtained with standard methods for CTA, and 2) marked tumor-liver attenuation differences (above 20 HU) persisted for more than 60 s in CTA-B and for not more than 20 s with conventional methods for CTA. The results show that CTA-B is superior to standard methods in enabling multiple scans of the liver during greater and prolonged differential tumor enhancement after administration of a bolus of contrast medium. In conjunction with table incrementation, CTA-B allows scanning of the entire liver at the time of maximal contrast enhancement with two to three injections of contrast medium. Two patients complained of abdominal pain during balloon inflation. No other complications were observed.

Bolus-rapid infusion of contrast medium: Simplified technique for optimal computed tomography pancreatography without use of dynamic scanning

Optimal pancreatic computed tomography demands the use of both narrow beam collimation and high levels of intravascular contrast medium. Dynamic scanning with or without table incrementation has been advocated, but not all patients are amenable to prolonged breath holding, and tube cooling requirements may limit the study. In addition, repeat boluses usually must be administered to adequately image the entire pancreas. Enhancement may also be less than uniform. We describe a simple method of pancreatic scanning using bolus injection and pressurized rapid infusion of contrast medium that yields consistently high-quality scans demonstrating both pancreatic parenchymal and peripancreatic vascular enhancement in most patients. The method eliminates the need for dynamic scans in most cases and improves the speed of examination and quality of patient care in a busy computed tomography department.

Fast overlapping scans in cerebral computed angiotomography.

Three to four overlapping cerebral CT scans were obtained after the injection of a single bolus of contrast medium. The rapid sequential dynamic scanning was carried out with table increments, while there was peak iodine density in the carotid artery. The demonstration of cerebral vessel lesions (aneurysms, moyamoya disease, arteriovenous malformations, arterial narrowing, etc.) is easier and safer with this method as compared with the conventional multiple injection technique.

Paragangliomas of the temporal bone: high-resolution CT studies.

Seventeen patients with 15 surgically proved paragangliomas involving the temporal bone and parapharyngeal spaces were examined with high-resolution computed tomography (CT). Scans were obtained in multiple axial (0 degree, 30 degrees) and coronal (70 degrees, 105 degrees) section planes using 1.5-mm collimation and table incrementation. The purpose of this study was to demonstrate the utility of HRCT in assessing tumor extent and size, with particular emphasis on intrinsic temporal bone invasion. The most characteristic HRCT signs of paraganglioma include: jugular fossa expansion, soft-tissue mass in the hypotympanum and sinus tympani, permeation of the infracochlear surface, dural ballooning adjacent to the jugular fossa (indicative of epidural tumor), anterior displacement of parapharyngeal fat planes, and extension into the proximal aspect of the eustachian canal. It is concluded that HRCT is the single most efficacious examination to determine tumor extent, especially when intratemporal invasion has occurred, and to define other additional clinically unsuspected lesions.

Work in progress: dynamic sequential computed tomography during arterial portography in the detection of hepatic neoplasms.

Dynamic sequential computed tomography with table incrementation during arterial portography (DSCTI-AP) of the entire liver was performed in an attempt to improve the detection of hepatic neoplasms. In 13 of 17 patients, DSCTI-AP detected more hepatic lesions than were detected by other imaging methods, including radionuclide liver scans, ultrasound, computed tomography, and hepatic angiography. In only one case, an extremely hypervascular hepatocellular carcinoma, hepatic angiography was superior to DSCTI-AP. DSCTI-AP is a simple technique that may be carried out as a part of hepatic angiography. We believe that DSCTI-AP is a sensitive and useful method for the accurate detection of hepatic neoplasms.

Dynamic incremental computed tomography in evaluation of the pulmonary hila.

Contrast-enhanced dynamic computed tomography (CT) with table incrementation between scans was used to evaluate the hila in 100 patients without hilar abnormality and 15 patients with hilar pathology. This method of hilar evaluation was found to be superior to conventional CT because hilar vascular structures could be clearly opacified. Opacification of normal hilar vessels permitted accurate detection of hypovascular hilar masses, some of which were very small, nonlobular, and invisible using conventional CT. The technique was also found to be useful in evaluating the hila in patients with pulmonary artery dilatation or pulmonary opacification contiguous with hilar borders. We recommend that contrast-enhanced dynamic incremental CT be used for hilar investigation in patients referred for hilar CT examination unless there is a specific contraindication to contrast medium administration.

Liver-spleen computed tomography a method tailored for infants and children

A detailed approach to liver-spleen computed tomography in the pediatric patient is presented, including sections on indications, patient preparation, sedation, technique of scanning, radiation dosimetry, and potential pitfalls encountered in scanning. The advantages of dynamic scanning with table incrementation are stressed.

Work in progress: high-resolution, thin-section computed tomography of the larynx.

Rapid sequential scanning with automatic table incrementation was used to obtain 1.5-mm contiguous sections through the entire larynx in 10 patients with laryngeal neoplasms. The procedure required less than nine minutes. Transaxial images and multiplanar reconstructions were of high quality and helped define the extent of disease. In two patients, the thin-section axial scans indicated areas of abnormality not seen on conventional 5-mm images.

Cranial computed angiotomography.

Table incrementation can be combined with rapid-sequence cranial computed tomography (CT). Multiple sections are examined while there is a high concentration of intravascular contrast material, resulting in improved visualization of normal and abnormal vascular structures compared with conventional postinfusion. A relatively small amount of contrast medium is needed (28 grams iodine). In selected cases these vascular phase images add important information for interpretation of the CT study.

High-resolution multiplanar CT images of the larynx.

The standard technique for computed tomographic evaluation of the larynx utilizes 5-mm contiguous transaxial sections. Multiplanar images reformatted with these sections have not been of clinical use. We have evaluated the practicality of utilizing coronal and sagittal reformatted images produced from contiguous 1.5-mm transaxial sections. The technique of rapid sequential scanning with automatic table incrementation allows 36 contiguous thin section scans to be acquired in less than 9 minutes. Phantom studies showed a marked improvement in spatial resolution with thin section reconstructions. Preliminary clinical evaluation shows visualization of smaller structures with improved edge definition of both low- and high-contrast structures.

Regional pulmonary ventilation measurements by xenon enhanced dynamic computed tomography: an update.

New developments in computed tomographic technology permit rapid, serial images that may yield information concerning tracer kinetics through a large tissue volume. One possible application of these developments is the derivation of local lung ventilation by observing the temporal changes of stable xenon concentrations. Preliminary results from six multilevel ventilation studies in dogs demonstrate that the lung may be repeatedly imaged during reproducible phases of respiration even when interscan table incrementation is employed to survey a number of tissue segments and breathing is permitted between scans. In addition, subanesthetic xenon concentrations provide adequate enhancement for possible quantification.

Dynamic sequential scanning with table incrementation.

Dynamic sequential scanning with table incrementation is a method of rapid computed tomographic head scanning in which a complete 10-section scan can be made in 2 minutes 40 seconds or less. Although some measurable and visible loss of low-contrast resolution occurs, there is no loss of high-contrast resolution. Monthly throughput of patients has been increased by about 30% since this technique was instituted.

Xenon enhanced dynamic computed tomography: multilevel cerebral blood flow studies.

Xenon enhanced computed tomography with a fast scanning mode and interscan table incrementation was used to derive local cerebral blood flow in a nonhuman primate 19 days following infarction. The in vivo autoradiographic methodology was used to derive blood flow in normal and diseased tissue at four different brain levels (slices) during a single inhalation study.

3 - Control of LH and FSH Release by LHRH: Influence of Putative Neurotransmitters

Dynamic sequential computed tomographic scanning with automatic table incrementation uses low milliampere-second technique to eliminate tube cooling delays between scanning slices and, thus, markedly shortens examination times. A total of 25 patients with spinal column trauma involving 28 levels were studied with dynamic scans and retrospectively reviewed. Dynamic studies were considerably faster than conventional spine examinations and yielded reliable diagnoses. Bone disruption and subluxation was accurately evaluated, and the use of intrathecal metrizamide in low doses allowed direct visualization of spinal cord or radicular compromise. Multiplanar image reformation was aided by the dynamic incrementation technique, since motion between slices (and the resulting misregistration artifact on image reformation) was minimized. A phantom was devised to test spatial resolution of computed tomography for objects 1–3 mm in size and disclosed minimal differences for dynamic and conventional computed tomographic techniques in resolving medium-to-high–contrast objects.