Fibrosis, portal hypertension, and hepatic volume changes induced by intra-arterial radiotherapy with 90yttrium microspheres.

PURPOSE: To identify changes in hepatic parenchymal volume, fibrosis, and induction of portal hypertension following radioembolization with glass microspheres for patients with metastatic disease to the liver. RESULTS: In our series of sequential bilobar (n = 17) treatments, a mean decrease in liver volume of 11.8% was noted. In this group, a mean splenic volume increase of 27.9% and portal vein diameter increase of 4.8% were noted. For patients receiving unilobar treatments (n = 15), mean ipsilateral lobar volume decrease of 8.9%, contralateral lobar hypertrophy of 21.2%, and a 5.4% increase in portal vein diameter were also noted. These findings were not associated with clinical toxicities. CONCLUSION: (90)Yttrium radioembolization utilizing glass microspheres in patients with liver metastases results in changes of hepatic parenchymal volume and also induced findings suggestive of fibrosis and portal hypertension. Further studies assessing the long-term effects are warranted.

Staging of colorectal cancer.

CT, MR, and TRUS play complementary roles in staging CRC. Further improvements in these techniques will improve the accuracy of preoperative staging and thereby help optimize patient treatment and outcome.

Acquired immunodeficiency syndrome (AIDS) of the abdominal organs: imaging features.

The liver, spleen, biliary tract, pancreas, and kidneys are commonly affected by opportunistic infection, malignancy, and inflammatory disorders during the course of human immunodeficiency virus (HIV) infection. Clinical manifestations of solid abdominal visceral involvement are protean and usually nonspecific, but it is important to establish a specific diagnosis promptly in these often critically ill patients. This presentation reviews the cross-sectional imaging spectrum of HIV-associated lesions of these organs.

Antioxidant effects of vitamin C in mice following X-irradiation.

The influence of supplemental vitamin C on the survival of nucleated bone marrow cells was examined in Swiss Webster mice following whole-body sublethal X irradiation (3.5 Gy). The vitamin protected these cells by a factor of 1.7 when cell count per tibia was taken as the biological end point. However, in studies with lethal whole-body irradiation (9 Gy) and 30 day survival as the end point, supplemental ascorbic acid (AA) had no significant effect on the biological outcome. Based on these studies, it appears that vitamin C is effective in protecting the nucleated cells at lower doses, but not at lethal doses. Studies on the mechanism of radioprotection by vitamin C at sublethal doses were carried out by following the response of endogenous AA and glutathione levels to X irradiation (3.5 Gy) on mice fed with regular as well as vitamin C rich diet. The results suggest that i) a glutathione controlled feedback mechanism regulates the plasma AA levels in mice; ii) the role of vitamin C against radiation damage is not only in the initial stages of radical scavenging but also in cellular redox processes mediated by glutathione.

Detection of occult esophageal narrowing with a barium tablet during chest radiography.

Dysphagia is a delayed symptom of esophageal constriction and often appears after the luminal diameter is reduced to less than 10 mm. Earlier diagnosis of benign or malignant strictures while clinically silent would be desirable; hence we investigated the detectability of occult esophageal lesions with the aid of an ingested barium tablet during routine chest radiography. We prospectively examined 300 patients older than 40 years, who were referred for chest films because of indications unrelated to the upper gastrointestinal tract. Each patient was instructed to swallow a 12.5-mm barium tablet with 100 mL of water immediately prior to the exposure of posteroanterior and lateral chest films. Radiographs of 17 patients (5.6%) revealed intraesophageal retention of the tablet, and their prompt evaluation with double-contrast esophagrams confirmed various structural or functional abnormalities in 15 patients. Therefore, the oral administration of a barium tablet during routine chest radiography is a simple efficacious method to assess esophageal patency and detect occult narrowings from structural or functional causes.

Cardiophrenic varices in portal hypertension: evaluation with CT.

PURPOSE: To determine the prevalence and appearance of cardiophrenic angle (CPA) varices at computed tomography (CT) in patients with portal hypertension (PHT). MATERIALS AND METHODS: A retrospective review was performed of 148 consecutive contrast material--enhanced abdominal CT scans of patients with PHT. The paracardiac region was assessed for tubular structures suggestive of varices. Variceal diameter and CT attenuation relative to adjacent liver were noted. RESULTS: Tubular structures consistent with CPA varices were noted in 29 cases and were more common on the right side than on the left. Mean CPA variceal diameter was 2.6 mm. In three cases, right CPA varices measured 10-13 mm in diameter, but no variceal enhancement was noted on initial dynamic CT images. Delayed CT demonstrated contrast enhancement that reflected delayed enhancement of the portal venous system. CONCLUSION: CPA varices, particularly on the right side, are not uncommon in patients with PHT. Varices should be considered and excluded as a cause of CPA masses, particularly before percutaneous biopsy. Delayed CT may be necessary to correctly delineate CPA varices.

Vitamins as radioprotectors in vivo. II. Protection by vitamin A and soybean oil against radiation damage caused by internal radionuclides.

Tissue-incorporated radionuclides impart radiation energy over extended periods of time depending on their effective half-lives. The capacity of vitamin A dissolved in soybean oil to protect against the biological effects caused by internal radionuclides is investigated. The radiochemicals examined are DNA-binding 125IdU, cytoplasmically localized H125IPDM and the alpha-particle emitter 210Po citrate. As in our previous studies, spermatogenesis in mice is used as the experimental model and spermatogonial cell survival is the biological end point. Surprisingly, soybean oil itself provides substantial and equal protection against the Auger effect of 125IdU, which is comparable to a high-LET radiation effect, as well as the low-LET effects of H125IPDM, the dose modification factors (DMFs) being 3.6 +/- 0.9 (SEM) and 3.4 +/- 0.9, respectively. The protection afforded by the oil against the effects of 5.3 MeV alpha particles emitted by 210Po is also significant (DMF = 2.2 +/- 0.4). The presence of vitamin A in the oil further enhanced the radioprotection against the effect of 125IdU (DMF = 4.8 +/- 1.3) and H125IPDM (DMF = 5.1 +/- 0.6); however, no enhancement is provided against the effects of alpha particles. These interesting results with soybean oil and vitamin A, together with data on the subcellular distribution of the protectors, provide clues regarding the mechanistic aspects of the protection. In addition, the data for vitamin A reaffirm our earlier conclusion that the mechanism by which DNA-bound Auger emitters impart biological damage is primarily indirect in nature.

Effects of diatrizoate and iopamidol on spermatogenesis.

RATIONALE AND OBJECTIVES: The biological effects of iodinated contrast media were examined by using spermatogenesis in mouse testis as the experimental model. METHODS: Spermhead survival and abnormality assays were used as the biological end points. Diatrizoate meglumine/diatrizoate sodium and iopamidol were administered intravenously at equal rates and concentrations. Testicular uptake and clearance of these contrast agents were examined by high-performance liquid chromatography techniques. Appropriate mannitol solutions were employed as osmolality controls. RESULTS: Intravenous administration of the contrast agent or its respective mannitol control resulted in approximately a 30% decrease in spermhead count. A dose-related experiment with mannitol demonstrated that the spermhead count decreased rapidly until 600 mOsm/kg was reached, beyond which this decrease was minimal. Clearance of both contrast media was complete in approximately 4 hours. No significant increase in the induction of spermhead abnormalities was observed. CONCLUSION: Osmotic substances, such as iodinated contrast agents, affect the process of spermatogenesis.

Assay of radiographic contrast agents in mice plasma and testes by high-performance liquid chromatography.

A new buffer system is reported for the analysis of radiographic contrast agents (RCAs) sodium meglumine diatrizoate, iohexol, and iopamidol in mice plasma and testes, on a reversed-phase HPLC with UV detection. The buffer consisting of 0.1 M NaH2PO4, 0.2 mM Na2EDTA adjusted to pH 3.1 with orthophosphoric acid and 2.5-5.0% acetonitrile (v/v) resolved RCA peaks for clear quantitation. The main advantages of this system are the ambient temperature of operation and direct sample injection without prior sample purification as required in the earlier procedures. Using this procedure, uptake and clearance kinetics of these RCAs were studied in mice plasma and testes, following iv injections via tail veins. The plasma levels of all the RCAs reached maxima between 5 and 15 min and dropped down sharply. At the end of 12 h they were virtually undetected (detection limits 0.64-0.71 micrograms/mL). The testicular levels also showed a similar trend and reached undetectable levels after 4 h. There were no signs of metabolism of these RCAs in plasma or testes. The present clearance kinetics in plasma compares very well with earlier reports of non-HPLC methods of assay.