Intervertebral disk-space infection: CT changes. Work in progress

Seven patients who had spinal interspace infections underwent clinical, laboratory, and radiographic examinations, and findings are reported. Lytic fragmentation of adjacent vertebral bodies is a characteristic appearance on CT scans. Sagittal-coronal reformations confirm the end-plate irregularity and establish the diagnosis. Since the changes of diskitis are delayed and often obscured by accompanying degenerative disease on plain radiographs, CT appears to offer a diagnostic modality that shortens the usual delay from onset of symptoms to diagnosis.

Paramagnetic agents for contrast-enhanced NMR imaging: a review

The use of paramagnetic agents for contrast enhancement may extend the diagnostic potential of nuclear magnetic resonance (NMR) imaging. Proton relaxation is enhanced in targeted organ systems after either oral or intravenous administration of suitable paramagnetic agents. A decrease in T1 and T2, the spin-lattice and spin-spin relaxation times, can then be observed as an increase in signal intensity on NMR imaging. Initial investigations have focused on development of agents incorporating either paramagnetic ions or stable free radicals. Principles in development and application are illustrated with examples from experiments using the Vanderbilt Technicare 0.5 T NMR imager.

Sonographic depiction of changes in ventricular size associated with repeated ventricular aspirations

Serial real-time cranial sonography was performed on 11 preterm neonates who had demonstrated progressive posthemorrhagic ventricular dilatation and were subjected to repeated ventricular aspirations. Changes in ventricular size were correlated with gestational age, birth weight, and extent and location of the intracranial hemorrhage, as well as the timing, frequency, and location of the ventricular aspirations and the average amount of cerebrospinal fluid removed. The sizes of both lateral ventricles of each neonate were measured and the occurrence of sequelae related to repeated ventricular aspiration was examined. Eleven ventricles diminished in size, eight increased, and there was no change in three. Two neonates had bleeding near the aspiration sites. It is concluded that repeated aspiration can be associated with a diminution in ventricular size in some neonates. It is recommended that alternative methods of treatment, such as serial lumbar puncture or external ventriculostomy, be attempted prior to initiating repeated ventricular aspirations.

Nuclear magnetic resonance of iron and copper disease states

The tissue levels of paramagnetic ions are an important factor in the determination of T1 values as observed by nuclear magnetic resonance (NMR) imaging. The increased levels of iron present in human disease states such as hemochromatosis lead to decreased T1 values. The mean liver T1 of three patients with iron storage disease was determined to be 130 msec, significantly different from the value of 154 msec, the mean for 14 normal controls. Whether NMR will be able to detect the increased copper levels in liver and brain in Wilson disease remains for further clinical trials to evaluate. NMR imaging, however, does serve as a noninvasive method for the diagnosis of states of iron overload and as a technique to follow progression of disease or response to medical therapy.

Palpable breast masses: evaluation by high frequency, hand-held real-time sonography and xeromammography. Work in progress

The purpose of this study was to evaluate the diagnostic virtues and limitations of the combined use of high frequency, real-time ultrasound scanning (US) using hand-held transducers and xeromammography (XM) in the evaluation of palpable breast masses. Seventy-one patients, who ranged in age from 14 to 88 years and who had histologically proved masses, were examined by both imaging modalities. US demonstrated the highest degree of accuracy in establishing the presence of cysts (96%) and fibroadenomas (89%). XM afforded better overall depiction of the breast and correctly identified seven carcinomas, five of which were prospectively diagnosed by sonography. When all types of breast masses were considered, the combined use of XM and US was more accurate (89%) than when either XM (70%) or US (85%) was used alone. For this reason, a combined approach using both modalities in the examination of most patients with palpable breast masses is advocated. The advantages and limitations of both XM and US in the evaluation of palpable masses are discussed and illustrated.

Serial sonography of posthemorrhagic ventricular dilatation and porencephaly after intracranial hemorrhage in the preterm neonate

Changes in ventricular size and brain parenchyma were documented in 40 preterm neonates with intracranial hemorrhage (ICH), who were serially examined for 3 weeks or more. Sonography disclosed a close relation between the severity of the intracranial hemorrhage and the development of progressive ventricular dilatation. Eighty percent of preterm neonates with minor degrees of intracranial hemorrhage (localized subependymal hemorrhage or subependymal hemorrhage with small intraventricular hemorrhage [subependymal/intraventricular hemorrhage]) did not develop significant ventricular dilatation, whereas all of the neonates with intraventricular and/or intraparenchymal hemorrhage developed moderate or severe ventricular dilatation. Spontaneous resolution of moderate and/or severe ventricular dilatation occurred by the end of the third week in about one-third of neonates with intracranial hemorrhage. Progressive ventricular dilatation was documented in 10 of 15 neonates with major intraventricular and/or intraparenchymal hemorrhage. The therapeutic implications of the findings are discussed.

Studies of blood flow employing duplex, pulsed Doppler real-time sonography

The physics of pulsed Doppler techniques have been recently applied to clinical evaluation of superficial blood vessels and the flow within them. Essential physical principles of pulsed Doppler ultrasound are presented, including spectrum analysis and flow measurements. Duplex instrumentation combining high-resolution real-time imaging and a pulsed-Doppler system is described. Indications for duplex carotid sonography are outlined. Clinical applications are discussed and examples of normal and pathologic states are shown. Finally, the role of duplex sonography in the evaluation of carotid vascular disease is compared to traditional arteriographic and contemporary digital subtraction angiographic methods.

Work in progress: potential oral and intravenous paramagnetic NMR contrast agents

The potential use of paramagnetic compounds as nuclear magnetic resonance (NMR) contrast agents was examined in vitro. The T1 relaxation times for serial dilutions of Cu2+, Cr3+, Fe3+, and Mn2+ ions in saline, gadolinium oxalate (a potential oral contrast agent) in suspension, and chromium EDTA (a potential intravenous contrast agent) in solution were determined. The effect on T1 of increasing the concentration of oxygen in solution was also examined. The relative magnitude of the decrease in T1 was, as expected, proportional to both the concentration of the paramagnetic substance and its effective magnetic moment. Thus NMR has the potential to detect differences in tissue oxygenation. By incorporating paramagnetic metal ions into insoluble compounds or stable complexes, toxicity can be dramatically reduced while maintaining a significant paramagnetic effect. Highly insoluble paramagnetic compounds or stable paramagnetic ion complexes can thus be utilized as effective NMR contrast agents with significantly diminished toxicity.

Work in progress: radionuclide imaging of indium-111-labeled eosinophils in mice

Eosinophils isolated from peritoneal exudates were labeled with indium-111-oxine and injected intravenously into sensitized mice. They became localized at sites of inflammation produced by intradermal injections of schistosomal antigen or Toxocara canis larvae, whereas labeled neutrophils did not. Intense uptake of eosinophils by normal spleen, liver, and bone marrow was noted, with tracer distribution effectively complete by 5 hours after injection. Indium-111-eosinophil studies appear to be quite sensitive to parasitic inflammatory reactions; in contrast, nonspecific inflammation such as that induced by turpentine causes localization of eosinophils, but to a lesser extent. This technique may be useful in the study of parasitic and allergic disease.

Radiographic techniques to evaluate paintings

Radiographic techniques may be helpful in evaluation of the condition of paintings for their restoration, preservation, and occasionally to determine their authenticity. On the basis of experience with several of these procedures, the utility of each method is described in reference to specific "diagnoses" regarding paintings. Radiographic techniques have several advantages over other methods; they are nondestructive, they may be used to survey the entire painting, and they are subject to quantitative and serial analysis.

Sonographic findings of pancreatitis in children

The size and echogenicity of the pancreas was evaluated with real-time and static sonography and correlated in an independent and retrospective manner with amylase values in 17 asymptomatic children, 19 children with acute pancreatitis, and 2 with chronic pancreatitis. A ratio of the greatest anteroposterior dimension of the body of the pancreas relative to the transverse lumbar vertebral body measurement (P/V ratio) greater than 0.3, when associated with a hypoechoic pancreatic parenchyma, was indicative of acute pancreatitis. The predictive value of a positive sonogram was found to be 0.93, whereas the predictive value of a negative sonogram was 0.78. These data indicate that sonography is a useful adjunct to amylase determinations in the detection of pancreatitis in children.

Neuroradiologic applications of intraarterial digital subtraction angiography

In the neuroradiologic evaluation of 118 patients using intraarterial digital subtraction angiography definite advantages and disadvantages were defined. Advantages include reduction of contrast medium volume, catheter time, and patient risk and discomfort. It also aids in angiographic planning. The paramount disadvantage is less spatial resolution compared with conventional film angiography.

Certificate-of-need in an antitrust context

Recent cases such as National Gerimedical Hospital and Gerontology Center v. Blue Cross of Kansas City have found that certificate-of-need (CON) legislation did not intend to remove antitrust considerations. This note discusses the exemptions from antitrust provided by the state action doctrine of Parker v. Brown as well as the Noerr-Pennington doctrine, both of which appear to protect provider input into the CON process. Providing information that assists decision-making must be carefully distinguished from providing data that serve the interests of physicians and hospitals.

Work in progress: ultrasonic texture of normal rat liver tissue using a standardized in vivo measurement

A prototype computer-augmented diagnostic ultrasound system was used in an investigation of the range of echo amplitudes obtained from measurements of normal exteriorized rat livers. A secondary goal was to develop a method for minimizing variations in measurement techniques and instrument stability. The average echo amplitude was obtained from a user-selected homogeneous region of the liver on a B-mode scan image. A similar B-mode scan of a commercially available liver tissue equivalent phantom was also obtained immediately after each rat liver measurement and was used as a calibration scan. A normalization factor developed from the calibration scan was used to correct all in vivo measurements for system variation. The average echo amplitude from the livers of a group of normal rats, when corrected by the calibration scan, exhibited a narrow range of values with a coefficient of variation of only 5%. The development of a technique that yields a narrow range of values for normal tissues should encourage further investigation of tissue characterization methods.

Simultaneous bi-plane digital video-fluoroscopy

A prototype system for digital subtraction angiography that is capable of acquiring digitized video-fluoroscopic images simultaneously from both anterior and lateral imaging chains of a conventional bi-plane system was developed. A hardware module that takes images from both the anterior and lateral video cameras and displays them both on a single video image prior to digitization was designed and constructed. The three-dimensional information provided by a digital bi-plane images should improve the accuracy of cardiac-ventricular function studies. In addition, bi-plane imaging should reduce the need for additional views and the associated repeated injections of contrast media. With this technique, digital bi-plane imaging can be carried out with commercially available systems without duplication of the digital-processing chain.

The potential impact of digital radiography (DR) on the speciality of nuclear medicine

Digital radiography is a reasonably economical system that helps diagnostic imaging physicians to develop increasingly less-invasive procedures, obtain maximal information at a given dose and increase the flexibility and convenience involved with diagnostic workups. The range of applications of DR has not been fully established at this time. Comparison of its properties with those of conventional nuclear medicine may suggest areas of potential application. Compared to nuclear medicine techniques, DR in general provides improved anatomical resolution, improved contrast resolution, sometimes equivalent functional information, and decreased imaging time. On the other hand, some functional nuclear medicine studies provide information not available by DR; including the gallium scan, bone scan, hepatic-biliary scan, and lung scan. Therefore, nuclear medicine procedures will be complimentary in some instances to digital radiography procedures and competitive in others. The proper roles of each modality in various clinical settings await future detailed and comprehensive efficacy studies.