Proper terminology for the left periaortic area.
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Biomedical subjects
Publications and source records attributed to M Vermess.
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The brain anatomy of ten men (aged 18 to 28 years) with persistent, severe developmental dyslexia was examined with magnetic resonance imaging to explore the possibility of visualizing pathology not seen in previous computed tomographic scan studies. Nine of the ten examinations were clinically normal. One showed a focal finding thought to be incidental to dyslexia. The volume of the temporal lobes was judged to be symmetrical in nine of ten examinations, a finding supportive of previous computed tomographic scan and neuropathologic reports of unusual symmetries of posterior brain regions. Thus, despite its sensitivity, magnetic resonance imaging failed to identify a common focal pathology. The choice of imaging planes (particularly coronal) and lack of bone artifact may, however, prove useful for studying macroscopic asymmetries in dyslexia.
Thirty-three patients with either primary spinal cord tumors (n = 18), intradural tumors excavating into the cord (n = 9), or spinal arteriovenous malformations (AVM) (n = 6) were studied with magnetic resonance (MR) imaging. In 25 of 38 examinations (66%) (five patients were studied twice), MR provided more information than that provided by other neuroradiologic procedures. In several cases, MR affected patient management decisions. Advantages of MR, in addition to the absence of ionizing radiation and its noninvasive nature, include good spinal cord-CSF-theca contrast, lack of bone-derived artifacts, ease of multiplanar imaging, improved discrimination between intra- and extramedullary lesions, better definition of tumoral cavities and possible distinction from true syringes, ability to help one recognize thrombus formation within an AVM, and ease of follow-up of cord lesions for possible size changes. Apart from factors precluding the study in several patients (life support systems, pacemakers, claustrophobia, neurovascular clips), disadvantages of MR imaging include motion artifacts (prevalent in thoracolumbar area), poor capability of typing and grading of tumors, potential of false-positive results, poor detection of calcification, and poor delineation of feeders and drainers of AVM.
A prospective study of computerized tomography (CT) of the liver using a liver contrast agent compared to conventional CT was undertaken. CT scanning without contrast agents (NC-CT), CT with water-soluble contrast (WSC-CT), and CT with ethiodized oil emulsion (EOE-CT) were performed on patients with possible or probable hepatic metastases. The findings on these three examinations were compared to the objective findings at surgery in 53 patients. Accuracy of these examinations was 80.7% for NC-CT, 77.1% for WSC-CT, and 84.9% for EOE-CT. The true-positive percentage for 129 hepatic lesions was 40.6% for the NC-CT, 33.6% for WSC-CT, and 76.7% for the EOE-CT. Eighty-three percent (44/53) of 1- to 2-cm liver lesions were detected by EOE-CT, whereas only 26.4% (14/53) lesions of this size were detected by the NC-CT and 20.4% (10/49) shown by WSC-CT. The likelihood that a lesion seen by CT scan was malignant was 84.6% for NC-CT, 89.4% for WSC-CT, and 81.8% for EOE-CT. The EOE contrast agent improves the sensitivity of liver CT for detecting hepatic metastases. The improvement occurs with lesions 1 cm and greater in diameter, but is particularly striking for lesions of 1 to 2 cm in diameter.
Monitoring the progression or regression of intraabdominal metastatic disease is required for knowledgeable management of chemotherapeutic regimens designed to treat metastases. Computerized tomography (CT) and CT with EOE-13, a liver contrast agent, allowed precise measurement of metastatic disease. The tumor doubling time of colorectal metastases in four patients was determined from serial CT scans of individual patients. Tumor doubling times of untreated patients varied from 50 to 95 days, and were in the same range for hepatic, lymph node, or intraperitoneal metastatic disease. These data may indicate that metastatic disease of colorectal cancer progresses at a faster rate in the peritoneal cavity than is reported for colorectal cancer metastatic to the lungs. The response to chemotherapy or progression of disease was also determined in treated patients. High resolution CT scanning with EOE-13 allowed calculation of tumor doubling times, and therefore more precise management of cancer patients with metastases.
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When lucent defects in the liver have a segmental configuration, they may be on an ischemic basis and related to decreased vascular perfusion. Portal venous inflow, by virtue of its low pressure, is particularly susceptible to diversion by focal intrahepatic masses, intravenous thrombi, or external compression. Innovative operative techniques for tumor enucleation may also result in lucent defects that can be confused with, or conceal, pathology. A hypothesis relating such defects to diminished portal inflow and reduced glycogen content is proposed.
Four patients with large right upper quadrant tumour masses of non-hepatic origin are presented. On initial clinical and radiological assessment, all cases were misinterpreted as either having a primary liver tumour or extensive invasion of the liver by an extrinsic tumour. Although angiography and CT scanning are most likely to yield an accurate diagnosis, they can be misleading. Vena cavography also gives important information in determining operability and at operation guides the retroperitoneal dissection. After thorough investigation an aggressive surgical approach to these tumours, with hepatic resection when necessary, provides the best chance of good palliation and possible cure.
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EOE-13 is an experimental liver-spleen-specific computed tomographic (CT) contrast agent developed at the National Institutes of Health. Experience with this agent in 225 clinical examinations is described. On average, use of EOE-13 increases the attenuation of normal liver by 32.5 H and that of normal spleen by 52.3 H. Tumors in these organs increase only 2.6 H, making them more easily detectable. Most of the iodine in EOE-13 appears to clear from the liver and spleen by 24 hr after injection. No deaths or permanent morbidity have been observed. The complication rate is 3.6%. EOE-13 is valuable for the detection of hepatic and splenic tumors.
Hepatic perfusion patterns were evaluated in five patients receiving hepatic artery infusion chemotherapy. All patients underwent 99mTc macroaggregated albumin (99mTc-MAA) scintigraphy and CT with EOE-13. In each case, the diagnostic agent was administered through the infusion catheter at 0.66 ml/min. Hepatic perfusion patterns were identified with both imaging methods, but CT with EOE-13 yielded more precise anatomic detail and was unique in demonstrating the perfusion status of each hepatic metastasis. Further evaluation of EOE-13 for this purpose is warranted.
EOE-13 was infused directly into the hepatic artery through a surgically implanted hepatic artery infusion pump in a patient with liver metastases. A computed tomographic scan obtained after EOE-13 infusion accurately showed the perfusion pattern of the implanted catheter. It also demonstrated the hepatic metastases more clearly than scintigraphy with 99mTc-macroaggregated albumin. EOE-13 may prove useful for the evaluation of hepatic perfusion patterns in patients receiving hepatic artery infusion chemotherapy.
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Nuclear magnetic resonance (NMR) and X-ray computed tomographic (CT) imaging of the brain were performed on nine patients with clinical evidence of cerebral involvement by systemic lupus erythematosus (SLE). Focal lesions were demonstrated in eight patients by NMR and in six by CT. The examinations with both techniques were negative in one patient and showed essentially identical pathological conditions in three patients. In three patients NMR demonstrated more numerous lesions than CT. All lesions seen on CT were also seen on NMR, mostly with greater clarity and extent. In view of the limited number of patients, this study is preliminary, but it appears that NMR demonstrates more accurately the degree of brain involvement in SLE than CT.
We tested five experimental liver-spleen specific computed tomography (CT) contrast agents, all of which are aqueous emulsions of iodinated vegetable oils. These compounds were compared with ethiodized oil emulsion 13 (EOE-13) and with a 5% dextrose in water control. We evaluated three animal/dose level models with both histology and CT to determine the best screening method for compounds of this type. We compared a rat/high dose model, a rat/medium dose model, and a rabbit/low dose model; the best discrimination was seen with the rabbit/low dose model. Histology of liver, spleen, and lung did not correlate with the attenuation values obtained from CT. We conclude that use of CT and a rabbit/low dose model is superior for screening compounds of this type. Of the compounds tested, only one, an emulsion of ethyl monoiodostearate (compound 208E), approached the effectiveness of EOE-13.
Accurate detection of hepatic metastases is necessary to properly stage and follow many malignancies. Nineteen patients underwent computed tomographic (CT) examination with ethiodized oil emulsion 13 (EOE-CT) and liver scintigraphy within 1 month of an exploratory laparotomy. The sensitivity, specificity, and accuracy of these two imaging procedures were evaluated statistically. No differences were seen when the patients were scored as positive or negative for metastases. However, in a lesion-by-lesion analysis of 58 hepatic lesions, the sensitivity of EOE-CT was 69.0% and the sensitivity of scintigraphy was 32.8% (p less than 0.001). All lesions detected scintigraphy were also detected by EOE-CT. EOE-CT had a size threshold of 1.0-1.5 cm, while liver scintigraphy had a threshold of 2.5-3.0 cm. EOE-CT is a more sensitive examination for detection of small hepatic metastases than liver scintigraphy.
A prospective study of the ability of laboratory tests and liver imaging tests to detect hepatic metastases was performed. Eighty patients at risk for hepatic metastases but without clinical evidence of disease were tested with 13 laboratory tests and three liver imaging tests. No single laboratory test had greater than 65% accuracy in the detection of hepatic lesions. No combination of the laboratory tests increased this accuracy. If the laboratory tests were used with one of the liver imaging tests, the accuracy was improved in some combinations to 76%. The CEA assay when analyzed in patients with colorectal primaries had an accuracy of 79%. The results show that the laboratory tests alone are not sufficiently accurate to detect liver metastases. Additional accuracy can be obtained by the combined use of a single liver imaging test and selected laboratory tests. Use of all the liver imaging tests and laboratory tests lowers the accuracy and increases the expense and thus is unnecessary.
This prospective study of 80 patients compared the results of liver scintiscan, ultrasound, and CT scan to the objective findings recorded at laparotomy. Analysis of these data revealed no significant differences in sensitivity, specificity, or accuracy among these three imaging procedures, although a trend toward increased accuracy of the CT scan was noted. In a composite analysis, the accuracy was not improved by combining two or all three of these examinations. A lesion by lesion analysis revealed the inability of any of the three currently used techniques to accurately detect lesions less than 3 cm in diameter.