Intratumoral administration of 5-[123I]iodo-2'-deoxyuridine in a patient with a brain tumor.

UNLABELLED: We have initiated a study in which patients suspected of having primary gliomas are given a single intracerebral injection of the thymidine analog 5-[123I]iodo-2'-deoxyuridine ([123I]IUdR). The purpose of the study is to determine the biodistribution of the radiopharmaceutical and to calculate dose estimates to the tumor and normal tissues. METHODS: A patient with a cystic glioma was injected with [123I]IUdR. Whole-body scans and brain scans were obtained at various times after injection, and blood, urine and stools were collected and assayed for radioactivity to assess its biodistribution and clearance. RESULTS: Scintigraphic imaging demonstrated that the distribution of radiolabeled IUdR was mainly confined to the tumor (injection site), stomach and bladder. Disappearance from the tumor site and blood clearance were delayed probably due to collection in the cystic lesion. Eighty percent of the injected dose was recovered in the urine. CONCLUSION: The pharmacokinetics of [123I]IUdR locoregionally administered to a human glioma in situ resembled those observed in a rat glioma model where administration of the radiopharmaceutical radiolabeled with the Auger electron emitter 125I was therapeutically effective.

Scintigraphy in the evaluation of arthropathy.

Significant progress has been made in radionuclide imaging of bones and joints. This largely is owing to advances in radiopharmaceuticals, particularly the antibodies, and in technology, particularly in the introduction of new computers and multiheaded camera systems resulting in improved imaging. These techniques have applied to the evaluation of articular and para-articular diseases including rheumatoid arthritis, septic arthritis, osteoid osteoma, transient osteoporosis, reflex sympathetic dystrophy, avascular necrosis, and facet joint syndrome. This article reviews scintigraphy in these conditions.

Bile duct disruption after laparoscopic cholecystectomy.

The reported prevalence of biliary tract disruption following laparoscopic cholecystectomy has ranged from 0% to 7% in early reports. We have reviewed the first 823 laparoscopic cholecystectomies performed at our institution and found 13 symptomatic biliary complications necessitating further therapy (prevalence 1.6%). This finding represents a decrease from the 2.7% prevalence found in our earlier series. The incidence of biliary complications will likely continue to vary depending on patient selection, operator experience, and new developments in laparoscopic technique. Bile duct injury and bile leaks are often difficult to diagnose but must be strongly considered in postoperative patients with abdominal pain, fever, jaundice, or continued bilious drainage from a surgical drain. Whereas computed tomography (CT) and sonography are sensitive in detecting perihepatic or free peritoneal fluid collections, they are nonspecific and definitive diagnosis of biliary tract injury requires hepatobiliary scintigraphy, endoscopic retrograde cholangiopancreatography (ERCP), percutaneous transhepatic cholangiography (PTC), or percutaneous aspiration. Disruption of the biliary tree has commonly been treated with reoperation or percutaneous drainage. More recently, endoscopic management has shown encouraging results for bile leaks and strictures in small series.

Iodine-131-metaiodobenzylguanidine scintigraphy in preoperative and postoperative evaluation of paragangliomas: comparison with CT and MRI.

Iodine-131-metaiodobenzylguanidine (MIBG) scintigraphy, transmission computed tomography and magnetic resonance imaging were used to evaluate 36 patients with clinically suspected functioning paragangliomas. The patients were divided into two groups. In Group 1 (n = 21), studied before surgery, patients mainly had benign adrenal disease. In Group 2 (n = 15), studied after surgery, patients frequently had malignant or extra-adrenal tumors. In Group 1, transmission computed tomography and magnetic resonance imaging were more sensitive (100% for both) than MIBG scintigraphy (82%), which, however, was the most specific (100%). In Group 2, MIBG scintigraphy and magnetic resonance imaging were more sensitive (83% for both) than transmission computed tomography (75%), but MIBG was again the most specific (100%). Thus, all three were complementary modalities for localizing paragangliomas both preoperatively and postoperatively. MIBG imaging is indicated for both groups but it is especially recommended for postsurgical patients with recurrence because the disease is often malignant or extra-adrenal.

CT and MRI of mycotic aneurysms of the abdominal aorta.

In two of three patients with mycotic aneurysms of the abdominal aorta, diagnosis was delayed, with a fatal outcome in one patient. A combination of studies, such as indium white blood cell scanning, and anatomical imaging modalities, such as CT and MRI, may be necessary to arrive at the correct diagnosis.

Intraperitoneal radioimmunotherapy of refractory ovarian carcinoma utilizing iodine-131-labeled monoclonal antibody OC125.

Refractory epithelial ovarian cancer is generally confined to the peritoneal cavity and is thus amenable to intraperitoneal (ip) therapy. Radiolabeled monoclonal antibodies raised to tumor-associated antigens offer the promise of selective tumor irradiation while reducing toxicity to normal tissues. We have conducted a phase I therapeutic trial to examine the feasibility of ip radioimmunotherapy utilizing escalating doses of 131I-labeled OC125 F(ab')2. Twenty-nine patients were each treated with a single dose of radiolabeled antibody. Twenty-eight patients were evaluable for dose-related toxicity. The toxicities most frequently observed were hematologic and gastrointestinal. Hematologic toxicity was noted in 5/14 (36%) patients receiving 18-87 mCi and in 12/14 (71%) receiving 100-144 mCi (P = 0.018). The median white blood cell nadir of 2-3K/microliters (range, 1.4-3.5K/microliters occurred at a median of 4.5 weeks and the median platelet nadir of 41K/microliters (range, 20-78K/microliters) at a median of 6.5 weeks. Mild gastrointestinal toxicity was observed in 4/14 patients (28%) at doses less than 100 mCi whereas at doses greater than or equal to 100 mCi, 11/14 (79%) patients developed nausea, vomiting, or chronic ileus (P = 0.021). This toxicity occurred most frequently in patients with protracted urinary 131I excretion. We conclude that 131I-labeled OC125 can be safely administered ip. Hematologic and gastrointestinal toxicity is predictable and related to the dose and rate of clearance of isotope.

Ga-67 scintigraphy and computed tomography in the diagnosis of pneumocystis carinii pneumonia in patients with AIDS. A prospective comparison.

A prospective evaluation of Ga-67 scintigraphy and transmission computed tomography was performed in 70 consecutive patients with AIDS who were suspected of having Pneumocystis carinii pneumonia. Studies were evaluated independently by two observers. Receiver operating characteristic curves were plotted. Although scintigraphy had a higher true-positive ratio at any false-positive ratio, statistically the areas under the two receiver operating characteristic curves were not significantly different. However, at an FP rate of 15% to 20% (one in the clinically reasonable range), the sensitivity for scintigraphy was 0.84 and for CT 0.80; corresponding specificities were 0.82 and 0.64, respectively, for the two modalities. It seems from these data that gallium imaging is probably superior to CT in detecting P. carinii pneumonia in this group of patients.

Bile duct disruption and biloma after laparoscopic cholecystectomy: imaging evaluation.

Disruption of the biliary tree after laparoscopic cholecystectomy has been reported in 0-7% of cases, and likely represents the most significant postoperative complication. Documenting the presence and extent of a bile leak is often difficult. We reviewed the first 264 laparoscopic cholecystectomies performed at our institution and found seven cases of bile extravasation and/or biloma formation (prevalence, 2.7%). All patients were first seen in the early postoperative period with abdominal pain and low-grade fever. Sonography was performed in five of seven, CT in five of seven, hepatobiliary scintigraphy with diisopropyliminodiacetic acid in five of seven, and ERCP in four of seven cases. While sonography and CT were initially helpful in determining the presence of abdominal fluid collections, they were unable to differentiate between postoperative seroma, lymphocele, hematoma, and bile leak. Hepatobiliary scintigraphy was useful in demonstrating continuity of these fluid collections with the biliary tree and guiding further therapy. Four cases were managed with endoscopic biliary decompression, with the use of sphincterotomy or nasobiliary stent placement, with good clinical result. The other three cases were treated surgically with T-tube or external drainage. All patients did well clinically, without evidence of bile reaccumulation. Our experience suggests that sonography and CT are useful in detecting postoperative fluid collections, but cannot differentiate bile from other fluids. Hepatobiliary scintigraphy is valuable as a noninvasive means of investigating possible bile leaks and in guiding further therapy.

Tc-99m MIBI SPECT in the assessment of myocardial reperfusion after percutaneous transluminal coronary angioplasty.

Tc-99m MIBI SPECT was used to assess the early benefits of successful percutaneous transluminal coronary angioplasty (PTCA) in nine consecutive patients. SPECT stress studies were done by artificial cardiac pacing just prior to PTCA and 16-20 hours later, with perfusion images obtained 2-3 hours after pacing stress and Tc-99m MIBI injection. Angiographic restenosis was demonstrated in three patients at a later date, and all of these showed no significant improvement on the perfusion study after PTCA. All four patients asymptomatic at 7 months following PTCA had an average 15% improvement in segmental perfusion after the procedure. In two patients symptomatic after PTCA, one showed angiographic patency and had greater than 15% improvement in perfusion, while the second showed no scintigraphic improvement (no angiographic data obtained). This preliminary study suggests that Tc-99m MIBI is an important adjunct to angiography in estimating the amount of myocardium "at risk" before and after PTCA.

Nuclear medicine techniques in septic arthritis and osteomyelitis.

Imagers are consulted to confirm the presence of acute osteomyelitis, to evaluate disease activity and chronic osteomyelitis, and to confirm the presence of a sequestrum in active chronic osteomyelitis. Scintigraphy remains the most sensitive and specific modality for the diagnosis of acute osteomyelitis and the evaluation of activity of chronic osteomyelitis. Computed tomography is the best examination for the confirmation of the presence of sequestra. In this article, the authors review the various radionuclide techniques, their applications in the different clinical settings, and the way in which they correlate with other imaging techniques.

Embolization of platelets after endothelial injury to the aorta in rabbits. Assessment with 111indium-labeled platelets and angiography.

This study exploits the ability of a collateral arterial network to trap platelet aggregates in order to document the frequency of macroembolization in rabbits after endothelial damage. Two weeks after ligation of the right superficial femoral artery, endothelial injury was induced in the distal aorta; within 3 hours the rabbits were studied using either angiography or 111indium-labeled (111In) platelet scintigraphy. Angiography indicated visible aggregates in the thigh region in eight of 19 and arterial occlusion in three of 19 rabbits. The collateral-dependent thigh also showed more 111In-labeled platelet activity than the contralateral side (P less than .001), whether platelets were injected before or 2 hours after injury. Radioactivity in the limbs of rabbits with no injury was distributed symmetrically. Blood pool volume, assessed with technetium-99m-labeled red blood cells, was the same in both thighs, and could not account for these observations. The findings indicate that platelet activation and aggregation after endothelial injury lead to microembolization much more frequently than it leads to macroaggregate formation and visible artery occlusion.

Acute diseases of the scrotum.

Several imaging modalities are available for evaluating the patient with acute scrotal pain. Until recently, scintigraphy was the initial procedure of choice in most patients, as it was the only noninvasive technique for determining integrity of blood flow to the testicle. Ultrasound was valuable when the scintiscan was inconclusive or in the setting of scrotal trauma. With the advent of color Doppler sonography, information about both structure and blood flow can be obtained by means of a single imaging study. If initial promising results with this newer technique are borne out, color Doppler is likely to become the primary diagnostic test in patients with acute scrotal pain. The role of MRI and MRS has yet to be defined.

Detection of focal infection by 111In-human polyclonal IgG.

Eleven patients with suspected foci of inflammation and/or infection were scanned with 111In-labeled polyclonal human IgG. Seven patients were suspected of having the source of their infection in the abdomen, three in the musculoskeletal system and one in the thoracic aorta. The test was truly positive in seven patients, truly negative in three and falsely negative in one. All the true positive cases showed abnormally increased radiopharmaceutical uptake at the site of infection by six hours, suggesting the diagnosis, although the intensity of uptake increased progressively 24 hours later. There were no untoward effects noted in this series. This examination is potentially useful in the early depiction of focal sources of infection/inflammation.

Detection of periodontal disease activity with a scintillation camera.

The goal of this study was to assess the ability of a scintillation camera method to detect areas of active bone loss due to periodontitis. Technetium 99m methylene diphosphonate was used as the bone-seeking radiopharmaceutical. Bone-seeking radiopharmaceutical uptake (BSRU) was imaged and quantified in alveolar bone regions of interest with a scintillation camera and a computer. Analysis of the sequential radiographs over six months constituted the basis for determination of sites of active disease. The study was composed of two parts. First, 18 subjects, nine with adult periodontitis and nine controls, were enrolled in a cross-sectional study to determine whether the quantitative scintillation amera methodology detected differences in BSRU in periodontitis vs. periodontally healthy patients. Second, the nine patients with periodontitis were studied longitudinally in order to determine whether the BSRU examination was indicative of bone loss subsequently measured radiographically. In the cross-sectional study, the mean uptake ratio for the periodontitis group was significantly higher than that for the control group (1.63 +/- 0.06 and 1.42 +/- 0.04, respectively, p less than 0.01, t test). From the longitudinal study, the mean patient scintillation image uptake ratios were highly correlated with the mean bone loss determined from serial radiographs (p less than 0.01). The accuracy, sensitivity, and specificity of the quantitative gamma camera method for detecting site(s) of active bone loss within the region of interest were assessed relative to the longitudinal radiographic data. The accuracy, sensitivity, and specificity were 85%, 90%, and 79%, respectively. Alveolar bone scintigraphy with a gamma camera and computer may provide a simple and valid technique for the immediate indication of areas of periodontal disease activity.

Platelet activation and aggregation after endothelial injury. Assessment with indium-111-labeled platelets and angiography.

Although platelet activation and aggregation after endothelial injury are well documented, the time course of platelet deposition and the relationship between platelet aggregation and the release of vasoactive products have not been fully clarified in vivo. To study the effect of platelet vasoactive products, a collateral blood supply was induced by ligating the superficial femoral artery in male New Zealand white rabbits. Two weeks later, endothelial injury to the distal abdominal aorta was produced by cytologic brush or mimicked with a metal coil embolus. Platelet aggregation was assessed with indium-111 (111In)-labeled platelets, and scintigraphy demonstrated significant, progressive platelet deposition up to 3 hours after injury and evidence of residual activity 24 hours later. Angiography showed that the time course of peripheral vasoconstriction matched closely that of platelet deposition, indicating release of vasoactive substances from the aggregating platelets. These pathophysiologic changes secondary to endothelial injury may have significant implications for intravascular interventional procedures.

Brain perfusion SPECT using an annular single crystal camera: initial clinical experience.

The annular single-crystal brain camera (ASPECT) is a digital SPECT system with a single-crystal sodium iodide thallium Nal(Tl) ring detector and collimator system designed to view the patient's head from three angles simultaneously. The ring is rotated concentrically to the detector for three-dimensional reconstruction over a 21.4 cm (diameter) by 10.7 cm (length) field of view. We evaluated the system clinically by imaging a Hoffman brain phantom and seven subjects, of whom two were normal controls, three had previous cerebral infarction and two had dementia. The ASPECT system produced tomographic images of high spatial resolution. In normal subjects, the separation of striata from thalami by the posterior limbs of the internal capsules was much clearer on ASPECT images than on rotating gamma camera images. The high spatial resolution obtained with the ASPECT system translates into superior anatomical representation of the brain compared to the standard rotating gamma camera.