Formation of large particles in a 99Tcm-tin colloid preparation

The effect of prolonged continuous movement on particle size within a 99Tcm-tin colloid preparation was investigated, making use of photon correlation spectroscopy for size estimation. No increase in particle size was found when the preparation was left undisturbed for up to 7 h, the mean (+/- S.D.) size being found to be 239 +/- 24 nm. When the preparation was placed in a laboratory rotator for the same period of time, there was a gradual increase in mean particle size to 404 +/- 127 nm. The increase in size was much greater, however, after 7 h of continuous agitation in a laboratory shaker, a mean value of 2260 +/- 746 nm being observed. An antimony sulphide colloid was subjected to continuous agitation for the same period of time but there was no evidence of aggregation. It is supposed that continuous movement of reconstituted 99Tcm-tin colloid, leading to a marked increase in particle size, may explain occasional instances of significant lung intake.     

Hepatobiliary scintigraphy with 99Tcm-HIDA and 99Tcm-sulphur colloid

The results of a study comparing the ability of ⁹⁹Tc^m-sulphur colloid and ⁹⁹Tc^m-HIDA to demonstrate circumscribed defects and obstruction of the biliary flow to the intestines are reported. As regards focal liver diseases, colloid scintigraphy (SC) had a nosographic sensitivity and specificity of 0.87 and 0.85, respectively. The corresponding figures for the HIDA scintigraphy were 0.40 and 0.92. The sensitivities are significantly different. Concerning the diagnosis of extrahepatic obstruction, sulphur colloid scintigraphy had a nosographic sensitivity and specificity of 0.31 and 0.94. The corresponding figures for HIDA scintigraphy were 0.69 and 0.84. These sensitivities are significantly different too. The most frequent cause of false results was a pattern of hepatocellular disease in sulphur colloid scans in patients with a longstanding biliary obstruction. The second most frequent error was due to circumscribed defects in SC as well as in HIDA scans in patients with obstructive diseases and a high value of serum bilirubin. A third source of error was the pattern of an obstruction in HIDA scans in patients with focal diseases. The significance of the star pattern the sulphur colloid scan in patients with obstruction is stressed, as the significance of this pattern not has been evaluated previously. It is concluded that the two different scintigraphic methods are complementary tools in the examination of patients with liver diseases     

Tc-99m PMT hepatobiliary scintigraphy in the differential diagnosis of extrahepatic metastases and hepatocellular carcinoma

PURPOSE: The authors evaluated the utility of hepatobiliary scintigraphy for tissue characterization of extrahepatic metastases from hepatocellular carcinoma (HCC) using Tc-99m N-pyrydoxyl-5-methyltriptophane (Tc-99m PMT). METHODS: We examined 13 patients with HCC (29 extrahepatic metastases and 3 benign bone lesions) and 5 patients with other cancers (15 extrahepatic metastases). Thirty minutes to 6 hours after intravenous administration of Tc-99m PMT, planar (all 47 lesions) and SPECT (42 lesions) images were obtained. Accumulation of Tc-99m PMT in the lesion was evaluated visually by comparing bone scintigraphy, computed tomography, magnetic resonance imaging, or all of these. RESULTS: Findings were positive in 12 of 13 patients with HCC and extrahepatic metastases (16 of 29 on planar imaging and 21 of 26 on SPECT). Findings in all three benign bone lesions and 15 metastatic lesions from non-HCC primary lesions were negative (0 of 18 on planar imaging, 0 of 16 on SPECT). There were no false-positive findings in these lesions. Lesion-by-lesion sensitivity, specificity, accuracy, and positive and negative predictive values were 55%, 100%, 72%, 100%, and 58% by planar imaging and 81%, 100%, 88%, 100%, and 76% by SPECT, respectively. CONCLUSIONS: Because of the high specificity and reasonable sensitivity, Tc-99m PMT appears to be useful for the differential diagnosis of extrahepatic metastases from HCC. SPECT improves the detectability of small or faint accumulation in metastases from HCC.     

Double-tracer scintigraphy with 67Ga-citrate and 99mTc-sulfur colloid in the diagnosis of hepatic tumors.

A method of liver scanning based on a subtraction technique with simultaneous use of two tracers, 67Ga-citrate and 99mTc-sulfur colloid, is described. The subtraction technique isolates radiogallium uptake by the space-occupying hepatic lesions by subtracting interference due to tracer uptake by healthy hepatic tissue. In 82 patients, the method yielded a correct result in 94.7% of the positive scans and in 97.7% of the negatives. Two false positives and one false negative occurred. Very poor results were obtained in the same patients using conventional technetium and gallium scans: only 20.7% of these interpretations were correct. The method proved very helpful in differentiating malignant from benign lesions.     

Splenic defect on 99mTc-sulfur colloid scintigraphy but not on CT in a patient with pancreatic carcinoma

A 99mTc-sulfur colloid (99mTc-SC) scintigraphic study of a patient with pancreatic carcinoma invading the splenic hilum demonstrated a discrete focal defect of the spleen, while computed tomography (CT) showed a normal spleen. The patient underwent splenectomy and no pathology was found in the spleen. The tumor invasion into the splenic hilum may have caused the defect shown in the 99mTC-SC study, reflecting splenic reticuloendothelial (RE) cell dysfunction, while CT might well represent anatomic structures only. This discrepant finding between functional (99mTc-SC) and anatomic (CT) imaging modalities may be explained by the fact that the impairment of the phagocytic function of the spleen apparently was not severe enough to cause structural changes detected by CT or gross and microscope examination.     

骨髓增殖性疾病全身骨髓分布变化的研究

目的 探讨用^99Tc^m-硫胶体显像观察骨髓增殖性疾病（MPD）全身骨髓分布改变及特点的临床意义。方法 患者85例，包括原发性骨髓纤维化（IMF）40例，真性红细胞增多症（PV）15例，原发性血小板增多症（ET）5例，慢性粒细胞性白血病（CGL）25例。^99Tc^m-硫胶体使用剂量370－550MBq(2-5mL)。结果 全身骨髓分布异常占88．2％，可见骨髓显像呈增强型、抑制型及抑制伴扩张型异常表现。中心性骨髓（CBM）抑制率及外周性骨髓（PBM）扩张率分别为61．2％及56．5％。IMF骨髓抑制型较增强型外周血象降低程度差异有显著性（P＜0．05）。CGL患者CBM抑制及PBM扩张程度均随病情缓解而减轻。各疾病间PBM扩张形态有一定差异。结论 胶体骨髓显像的不同类型与MPD外周血象、临床病程及病情缓解状态有关；骨髓显像有助于MPD的鉴别诊断，了解MPD患者临床状态及预后。     

Technetium-99m glucoheptonate as a scanning agent in hepatocellular carcinoma

Technetium-99m glucoheptonate (Tc-99m GH) is concentrated in pulmonary and cerebral tumors. The purpose of this study was to assess the uptake of this radionuclide by hepatocellular carcinoma. Its concentration by the primary tumor was compared with that in the non-neoplastic hepatic tissue in 31 patients who showed obvious defects on a colloid scan, and its uptake by pulmonary metastases was examined in six patients with x-ray evidence of this complication. In two patients, the uptake by the tumor was greater than, in six it was equal to, and in ten it was less than that in the non-neoplastic hepatic tissue. In the remaining 13 patients, there was no concentration at all in the tumor. In none of the six patients with multiple pulmonary metastases could uptake of Tc-99m GH by the metastases be demonstrated. It is concluded that Tc-99m GH is of limited value in the diagnosis of primary or metastatic hepatocellular carcinoma.     

Rim sign in Tc-99m sulfur colloid hepatic scintigraphy

A case of pericholecystic hyperperfusion on Tc-99m sulfur colloid (SC) flow images with a pericholecystic rim of increased activity (PCHA) on delayed planar and single-photon emission computed tomography images of the liver was seen in a patient with a history of multiple renal transplants admitted with cramping right lower quadrant abdominal pain. Laparotomy performed 5 days after the scan revealed an acutely perforated gangrenous gallbladder and occluded cystic duct. The secondary findings of gallbladder hyperperfusion and PCHA or "rim sign" have been frequently reported with Tc-99m IDA hepatobiliary imaging. These secondary findings in conjunction with a nonvisualized gallbladder on an IDA scan suggest a complicated or advanced stage of acute cholecystitis and usually require urgent surgical intervention. The rim sign on Tc-99m SC scintigraphy also likely indicates the same grave diagnosis.     

Intra-arterial and intraportal infusion liver scintigraphy using 99mTc-labeled colloid]

Intra-arterial infusion liver scintigraphy was performed in 11 patients with primary or metastatic liver tumor, and intraportal infusion liver scintigraphy was performed in 6 patients for prophylaxis of liver metastasis from colorectal cancer. 99mTc-Sn colloid or 99mTc-phytate was administered through the catheter of which tip was placed in the portal vein or the hepatic artery, and then liver image was obtained. When 99mTc-phytate was infused intra-arterially, significant amount of the infused tracer passed through the liver and we could not get sufficient information to assess the distribution of drug administered through the catheter. On the other hand, intraportal infusion liver scintigraphy using 99mTc-Sn colloid or 99mTc-phytate and intra-arterial infusion liver scintigraphy using 99mTc-Sn colloid revealed heterogeneity of liver uptake, tracer uptake in spleen, low uptake area corresponding to the liver tumor and high uptake area around it. The findings will be clinically useful, and these methods are thought to be helpful to confirm the satisfactory drug distribution.     

Radionuclide angiography and scintigraphy in hepatocellular carcinoma

Among 1 257 patients subjected to liver-spleen (RES) scintigraphy and radionuclide angiography (RNA), there were 13 cases of histologically confirmed hepatocellular carcinoma (1%). All 13 patients had scintigraphic findings indicating cirrhosis. Histologically, cirrhosis was present in only 9 out of 11 cases in which liver parenchyma was available for examination. One patient had hemochromatosis without evidence of cirrhosis. In 11 cases, the tumor was clearly demonstrated as a defect in the static scintigram. However, in 2 cases with cirrhosis and poorly differentiated hepatocellular carcinoma, the tumor nodules were hardly discernible. In RNA, the tumor displayed high activity in the arterial phase and decreasing activity during the portal phase, ending up as a defect. At RNA, the lesion was clearly outlined in 12 cases, including the 2 patients in whom the scintigraphic findings were inconclusive; in one case with severe cirrhosis and a well differentiated hepatocellular carcinoma, the tumor was barely detectable. We conclude that a combination of RNA and scintigraphy is a valuable screening which usually provides a correct diagnosis in hepatocellular carcinoma.     

Utility of Tc-99m GSA whole-body scintigraphy in detecting bone metastases from hepatocellular carcinoma

Recent advances in the treatment of hepatocellular carcinoma (HCC) have prolonged patient survival. However, the number of patients with bone metastases identified during follow-up examinations has increased. Tc-99m Sn-N-pyridoxy-5-methyltryptophan (Tc-99m PMT) has been reported to accumulate at a high rate in HCC lesions and bone metastases. In the patient described here, whole-body scintigraphy showed accumulation of DTPA galactosyl human serum albumin (Tc-99m GSA) and Tc-99m PMT in bone metastases from HCC. The authors suggest that asialoglycoprotein receptors may be present in bone metastases from well-differentiated HCC. Tc-99m GSA whole-body imaging can be used to detect bone metastases from HCC and to evaluate hepatic reserve.