Biomedical subjects
Publications and source records attributed to D R Enzmann.
Comparison of different contrast dosages in adult patients with malignant gliomas studied by computed tomography indicates that 28-42 g of iodine is required for clinically diagnostic results. This can be translated into a 10 min iodine blood level of 100 mg/100 ml. Contrast doses in the range of 14 g of iodine are not satisfactory.
Review of 22 cases of meningioma indicates that this lesion occurs slightly more frequently on the left but without predilection for sex or age of the patient. The presenting symptoms were nonspecific. Plain radiographs of the skull sometimes demonstrated calcification in the tumor, but more often did not. Cerebral angiography frequently showed enlargement and displacement of the anterior choroidal artery on the side of the tumor; the lateral posterior choroidal artery on the side of the tumor was also enlarged and displaced in seven of nine patients who underwent vertebral arteriography. Pneumoencephalography accurately demonstrated the site and size of the lesion, as did radionuclide scanning if the lesion was vascular. Computerized tomographic (TC) scanning also determined the location and size of the tumors, as well as their mass effect and vascularity; CT scanning also demonstrated calcification that was not visible on the plain skull radiographs in two of six patients who underwent CT scanning and had calcification.
Four patients with anorexia nervosa were studied by cranial computed tomography (CT). Three of the four demonstrated abnormal enlargement of cortical sulci and subarachnoid spaces as compared with an age-matched control group. The relationship of this finding to established neuropathological changes in anorexia nervosa is discussed.
The value of orbital CCT scans was studied by grouping the CCT scans of 196 patients into clinical diagnostic categories. In 83% of patients with suspected Graves' ophthalmopathy, CCT confirmed the diagnosis. The CCT scan differentiated patients with Graves' disease from those with orbital pseudotumour or malignancies. The CCT scan was positive in 92% or patients with proven orbital malignancies. In 73% of patients with proptosis of unknown aetiology, and in 56% of patients with ocular motility problems, the CCT scan led to the diagnosis. The CCT scan ruled out orbital mass lesions in cases of optic neuritis, optic atrophy or vascular malformations. The greatest value of the CCT scan was in the localization and determination of the size and shape of various orbital lesions and in the accurate follow-up of those lesions utilizing serial scans.
The CT findings in both the typical and atypical presentations of the Sturge-Weber syndrome are characteristic if not pathognomonic in most cases. The typical gyriform cortical calcification and cortical atrophy are well demonstrated whether associated with a small or enlarged hemicranium. Contrast enhancement was demonstrated in both cases where contrast medium infusion was performed.
The preliminary results with computer tomography in cisternography with metrizamide (Amipaque) indicates that both normal and abnormal cerebrospinal fluid dynamics can be accurately displayed with the advantage of spatial and quantitative detail. The pharmacokinetics of metrizamide clearance from cerebrospinal fluid to blood are similar to those of nuclides. Hence, similar problems in predicting response to ventricular shunting may arise. However, the quantitative features of this method have yet to be fully exploited.
This investigation determined the site(s) of elicitation and origin of secondary peristalsis in the human esophagus and characterized the upper esophageal sphincter (UES) and proximal esophageal body responses accompanying intraluminal distention. In 7 normal persons, an intraluminal transducer probe manometrically recorded the UES and 5- and 10-cm levels of the esophageal body. A second probe with a balloon attached 2 cm above the proximal strain gauge was located so that the balloon was 3 and 4 cm below the UES and 4 distentions were done. The balloon probe was moved in 2-cm increments (four distensions at each site) until lower esophageal sphincter pressures were recorded. No secondary peristalsis occurred after distention in the proximal 6 cm. The incidence of secondary peristalsis increased as the distention site moved distally. Sixty-nine per cent of secondary peristaltic waves orignated in the esophageal body proximal to the distention site. The UES pressure significantly increased over resting pressure (augmentation) during 63% of distentions. The esophagus proximal to the balloon and below the UES usually responded to distention with augmentation. Augmentation of the UES and proximal esophageal body in response to esophageal intraluminal distention and the resultant initiation of secondary peristalsis above the distention site comprise a highly integrated pressure barrier to esophagopharyngeal reflex.
Clinical findings are often insufficient to diagnose basal arachnoiditis and conventional neuroradiological techniques often fail to demonstrate the inflammatory process. Computed tomographic (CT) scans, however, usually can demonstrate the circle of Willis, and the basilar, sylvian quadrigeminal, and vermian cisterns. Cisternal anatomy can also be delineated on the CT scans by metrizamide cisternography. CT scanning may prove to be the most accurate and sensitive radiographic test for basal arachnoiditis. Findings in three patients are reported.
Sixty-three patients with malignant glioma undergoing chemotherapy and radiotherapy were evaluated with electroencephalography, 99mTc-DTPA imaging, and computed tomography (CT). Tumor size, central lucency, contrast enhancement, surrounding edema, and ventricular size were assessed. CT findings were found to be reliable and often predicted the clinical course. Tumor size, central lucency, and contrast enhancement increased in patients with clinical deterioration and decreased in those with improvement. The CT scan also provided additional information of value in adjunctive therapy, such as the presence of cysts or ventricular obstruction. In general, CT gave a more complete profile of tumor characteristics than other diagnostic modalities.
Spectroscopic images of the brain have great potential in disease diagnosis and treatment monitoring. Unfortunately, interfering lipid signals from subcutaneous fat and poor water suppression due to magnetic field inhomogeneities can make such images difficult to obtain. A pulse sequence that uses inversion recovery for lipid suppression and a spectral-spatial refocusing pulse for water suppression is introduced. In contrast to methods that eliminate fat signal by restricting the excited volume to lie completely within the brain, inversion-recovery techniques allow imaging of an entire section without such restrictions. In addition, the spectral-spatial pulse was designed to provide water suppression insensitive to a reasonable range of B0 and B1 inhomogeneities. Several data processing algorithms have also been developed and used in conjunction with the new pulse sequence to produce metabolite maps covering large volumes of the human brain. Images from single- and multisection studies demonstrate the performance of these techniques.
Cross relaxation between macromolecular protons and water protons is known to be important in biologic tissue. In magnetic resonance (MR) imaging sequences, selective saturation of the characteristically short T2 macromolecular proton pool can produce contrast called magnetization transfer contrast, based on the cross-relaxation process. Selective saturation can be achieved with continuous wave irradiation several kilohertz off resonance or short, intense 0 degree pulses on resonance. The authors analyze 0 degree binomial pulses for T2 selective saturation, present design guidelines, and demonstrate the use of these pulses in spin-echo imaging sequences in healthy volunteers and patients. Using the phenomenologic Bloch equations modified for two-site exchange, the authors derive the analytic expressions for water proton relaxation under periodic pulsed saturation of the macromolecular protons. This relaxation is shown to be monoexponential, with a rate constant dependent on the saturation pulse repetition rate and the individual and cross-relaxation rates.
Cine phase-contrast (PC) magnetic resonance (MR) pulse sequences have been used to measure blood flow in a variety of vessels. Because the cine PC sequence is time-consuming, this prospective study was undertaken to compare it with an ungated PC technique for measuring average blood flow in individual cerebral arteries to potentially achieve substantial time savings. The following cerebral arteries were studied in 10 healthy volunteers: carotid, basilar, middle cerebral, anterior cerebral, and posterior cerebral. Imaging planes were placed perpendicular to the vessel of interest, and velocity encoding, ranging from 40 to 250 cm/sec, was matched to individual arteries. Good correlation between cine and ungated PC blood flow measurements was obtained for both high- and low-flow vessels, with an overall correlation coefficient of .978. The ungated PC sequence, because of its short imaging time, allows measurement of the blood volume flow rate in the circle of Willis in approximately 20 minutes, a clinically acceptable time.
Normal blood flow and velocity in the superior sagittal sinus were measured in 30 patients. A fast two-dimensional ungated phase-contrast (PC) pulse sequence was compared with a peripherally gated cine PC technique for velocity and flow quantitation. The same imaging parameters were used for both methods. Measured values for mean velocity and flow obtained with the two methods were compared by using regression analysis and t testing. For blood flow, the correlation coefficient was .976. For velocity measurements, r was .950. Mean flow was 285 mL/min +/- 19 with the ungated PC method and 281 mL/min +/- 19 with the cine PC method. The mean velocities measured with the two methods were 12.94 cm/sec +/- 1.1 and 13.59 cm/sec +/- 1.1, respectively. There was no significant difference (paired t test) between the methods for mean flow or velocity data. This was true even though flow in the superior sagittal sinus is moderately pulsatile, as shown with the cine PC technique. The ungated PC method provided these data in 13 seconds versus 3.5 minutes for the cine PC method.
In newborn rabbits, the early cerebral metabolic changes caused by hypoxic-ischemic (H-I) insult was examined by using volume localized 1H-MRS (STEAM). Partial ischemia was caused by unilateral carotid artery ligation, and hypoxia was induced by 10% oxygen inspiration for 150 minutes. Lactate immediately increased after hypoxia induction and almost disappeared 120 to 150 minutes after removal of hypoxia in both H-I and hypoxia-only experiments. Lactate production correlated well with decrease of the blood oxygen saturation. More lactate was produced on ischemic side 50 minutes post-hypoxia induction in H-I study. Ischemia alone did not cause any significant lactate production. Lactate caused by hypoxia can be dynamically monitored by localized 1H-MRS. Existence of regional ischemia can induce greater anaerobic glycolysis and may affect the pattern of brain injury under hypoxia. 1H-MRS is a sensitive tool to detect the acute metabolic change caused by H-I insult.
Intravenous and intraarterial DSA studies were performed in patients being evaluated for possible neoplastic disease. DSA studies were obtained of the head, neck, chest, abdomen and extremities to evaluate the potential use of this technique in the cancer patient's workup. The results of this study suggest that many cancer patients can have the extent of tumor involvement defined using intravenous digital subtraction angiography. However, due to the number of false negative examinations, this study should not be relied upon as the only screening procedure. The current best application of DSA appears to be its use in conjunction with intraarterial injections as a faster and more economical alternative to angiography and in following up these neoplasms with intravenous DSA after appropriate therapy to evaluate possible recurrence or metastatic spread. Hybrid subtraction techniques and/or the development of new contrast media may greatly facilitate the use of intravenous DSA in conjunction with cancer diagnosis.
The neat liquid and an emulsion of two perfluorocarbon compounds were injected into the knee joints of dogs and a human cadaver to investigate their applicability for arthrography. Excellent delineation of joint structures was observed for as long as 24 hours, but after 24 hours each contrast agent leaked out of the joint capsule into surrounding tissue. Light microscopy of joint tissue revealed a synovial proliferative reaction and a foreign-body granuloma reaction in surrounding tissues. No clinically apparent adverse side effects were evident in the test animals.
Iosulamide meglumine, a new intravenous biliary contrast agent, was evaluated as a potential hepatic contrast agent utilizing computed tomographic scanning. Time-density data in dogs were generated following 56.7 and 75.6 mg iodine/kg body weight. The iodine was administered both as an iosulamide meglumine bolus injection and a 0.77 ml/min infusion. The greatest increase in x-ray attenuation (24 HU) was observed within 45 minutes after the 75.6 mg iodine/kg body weight infusion technique, which resulted in excellent hepatic opacification. The long duration of increased x-ray attenuation of hepatocytes produced by iosulamide meglumine would be useful in the CT detection of hepatic mass lesions which do not contain normally functioning hepatic cells.
Using computer calculations and assumed contrast bolus curves, several aspects of the application of temporal integration methods and matched filtering to intravenous digital subtraction angiography (IV-DSA) were studied. The topics included the improvement in signal-to-noise ratio (SNR) of the final image provided by simple integration, a comparison of the SNR performance of matched filtering and extensive integration, the degradation of SNR caused by the motion of noniodinated objects and the sensitivity of SNR to variations in DSA bolus dynamics from patient to patient. Additionally the dependence of matched filter SNR on exposure position and duration was both estimated and demonstrated with clinical DSA images. The results indicate that a substantial improvement in SNR can be obtained with only moderate integration increasing to a two X improvement for longer durations. Integration methods are able to withstand moderate durations (2 seconds) of motion and still provide image quality superior to more conventional DSA results.