The "SAPHO" syndrome: a case report of a patient with unusual bone scan findings

PURPOSE

The authors describe the clinical and bone scintigraphic findings of the SAPHO syndrome, which is characterized by synovitis, acne, palmoplantar pustulosis, hyperostosis, and osteitis. The case report illustrates the significance of bone scintigraphy in the diagnosis. It shows that Tc-99m MDP scanning can detect signs of arthritis not seen with other imaging methods, because the arthritis is inflammatory in nature and does not always cause bone erosion. Thus it is not visualized on plain radiographs. Knowledge of this disorder may help in the differential diagnosis of arthritis.

MATERIALS AND METHODS

Tc-99m MDP bone scintigraphy was used to diagnose arthritic changes. Whole-body and multiple delayed spot images were obtained in a 39-year-old diabetic, hypertensive woman who had tenderness in the plantar aspect of her heels. Swelling of the small and large joints of the feet, ankles, knees, hips, right sacroiliac joints, and shoulders was noted. She also had hydradenitis suppurativa and a history of a previous episode in which the arthritis improved after surgical treatment for the hydradenitis.

RESULTS

All active joint lesions were visualized on the bone scan, including the arthritis, which was not detected with other imaging methods. They were all well demonstrated in the bone scintiscan. The scan findings, along with the presence of hydradenitis, led to the correct diagnosis of SAPHO syndrome.

CONCLUSION

Tc-99m MDP bone scanning may be helpful in diagnosing arthritis as associated with the SAPHO syndrome.

Potential pitfall in parathyroid sestamibi imaging resulting from a cardiac pacemaker

A 47-year-old woman with a history of end-stage renal disease and hyperparathyroidism after total parathyroidectomy had Tc-99m sestamibi imaging to identify possible ectopic parathyroid tissue. This study was prompted by increasing calcium and parathyroid hormone levels after several years of taking calcium supplements necessitated by a surgically induced hypoparathyroid state and end-stage renal disease. The scan showed persistent linear activity in the upper right mediastinum in delayed images, after washout of the thyroid had occurred. Because of the unusual configuration of this finding, investigation of the patient's clinical history and other imaging studies was undertaken. The authors concluded that the unusual mediastinal uptake was not hyperactive parathyroid tissue, but rather was attributed to the presence of central venous pacemaker wires. Thus, this case illustrates a potential pitfall in parathyroid sestamibi imaging, the uptake of which may increase in the presence of a cardiac pacemaker, and it emphasizes the importance of correlative imaging.

Carcinoembryonic antigen immunoscintigraphy complements mammography in the diagnosis of breast carcinoma

BACKGROUND

An adjunctive noninvasive test that is predictable and highly specific for breast carcinoma would complement the high false-positive rate of mammography in certain patients.

METHODS

This prospective, multicenter study evaluated the accuracy, safety, and immunogenicity of carcinoembryonic antigen (CEA) antibody imaging in women with known or suspected breast carcinoma. Scintigraphic breast images were obtained approximately 3-8 hours after the administration of technetium 99m ((99)Tc) labeled anti-CEA Fab' and correlated with histopathology.

RESULTS

The (99)Tc labeled anti-CEA Fab' detected tumor CEA expression in 46 of 49 women (94%) initially entered with known primary breast carcinoma regardless of histology or serum CEA levels. In women scheduled for biopsy confirmation of mammographic and physical examination findings, 104 (99)Tc labeled anti-CEA Fab' studies had a sensitivity of 61% (17 of 28 cases) and a specificity of 91% (69 of 76 cases). In total, (99)Tc labeled anti-CEA Fab' detected 52 of 62 invasive ductal carcinomas, 5 of 5 invasive lobular carcinomas, and 3 of 6 noninvasive tumors (2 ductal carcinomas in situ and 1 intracystic papillary carcinoma). Tumor size significantly affected sensitivity (P = 0.041), with 11 of 14 missed lesions </= T1, and proliferative histology significantly affected specificity (P = 0.012), with 5 of 7 false-positive tumors being premalignant. In 50 breast carcinoma patients, (99)Tc labeled anti-CEA Fab' also demonstrated axillary lymph node involvement regardless of serum CEA levels, with a sensitivity of 80% when more than three lymph nodes were positive. No immune response or other meaningful side effects occurred.

CONCLUSIONS

(99)Tc labeled anti-CEA Fab' had high specificity and positive predictive values for breast carcinoma and the majority of false-positive studies were associated with an increased risk of malignancy. Improved imaging techniques, including dedicated gamma cameras for breast and axillary lymph node imaging, will likely improve the test's sensitivity for smaller lesions.

Rapid diagnostic imaging of acute, nonclassic appendicitis by leukoscintigraphy with sulesomab, a technetium 99m-labeled antigranulocyte antibody Fab' fragment. LeukoScan Appendicitis Clinical Trial Group

BACKGROUND

The purpose of this study was to evaluate the safety and efficacy of a technetium 99m-labeled antigranulocyte antibody Fab' fragment (sulesomab) as a diagnostic imaging agent in patients with suspected acute, nonclassic appendicitis.

METHODS

This prospective multicenter trial involved 141 children and adults with suspected acute, nonclassic appendicitis. The investigators interpreted planar images acquired 15 to 30 minutes and 1, 2, and 4 hours after injection and also by single-photon emission computed tomography (SPECT). The imaging results were confirmed surgically, whereas nonsurgical patients were considered as not having appendicitis (intent to treat).

RESULTS

Sulesomab had a sensitivity of 91% (29/32 patients) and a negative predictive rate of 97% for acute appendicitis. It detected additional abnormalities in 7 of 9 patients with other inflammatory abdominal disease and had a specificity of 92% (91/99 patients) and a positive predictive value of 80% for surgically confirmed right-lower-quadrant disease. In positive studies, 26% were identified by planar imaging at 15 to 30 minutes, 46% by 1 hour, 63% by 2 hours, and 71% by 4 hours; 29% required SPECT to detect the abnormality. Scanning time was 5 to 10 minutes per planar image and about 45 minutes for a SPECT study. Investigators found that sulesomab would have changed clinical management or reduced additional diagnostic studies in 64% of the patients. Adverse events were infrequent, minor, and self-limiting (9/141 patients, 6%). No human antimurine antibody response occurred in 48 evaluable patients.

CONCLUSIONS

Sulesomab is safe, well-tolerated, and with no apparent immunogenicity. Focal inflammation or infection in the setting of suspected atypical appendicitis is rapidly and accurately detected. Management decisions incorporating sulesomab imaging potentially provide clear patient benefits, especially by correctly predicting surgery to be unnecessary in 97% of patients without acute appendicitis.

The radiology of the thoracic manifestations of AIDS

The thoracic manifestations of AIDS have undergone a gradual metamorphosis, partly due to more awareness about the disease leading to earlier diagnoses and partly due to the fact that research has produced more effective prophylaxis as well as treatment for these patients. Many patients now demonstrate partial or complete clinical response which prolongs the length and quality of life of individuals positive for the Human Immunodeficiency Virus (HIV+). Also, with the large number of infected individuals coming to medical attention, and the years of experience in diagnosing and treating these AIDS patients, we now recognize not only the usual but also less usual manifestations of thoracic illnesses in AIDS, including infections, non-infectious diseases such as HIV associated Lymphocytic Interstitial Pneumonia and the neoplasms associated with AIDS. A section will be devoted to HIV infection in children. We will finish the article with a discussion of the current role of Nuclear Medicine in the diagnosis of HIV associated thoracic diseases. These topics are the subject of this article.

Demonstration of dose-dependent global and regional cocaine-induced reductions in brain blood flow using a novel approach to quantitative single photon emission computerized tomography

Ischemic stroke is a common cause of morbidity and mortality in cocaine addicts. Because the previous semiquantitative single photon emission computerized tomography (SPECT) method for measuring brain blood flow does not quantify blood flow, the magnitude and specificity of cocaine's effects during drug taking has not been well established. Here, using a novel quantitative approach to SPECT, we established that intravenous cocaine administration to nine recently abstinent cocaine-dependent subjects was associated with significant decreases in global and regional brain blood flow to dopamine-rich areas such as the prefrontal, frontal temporal, and subcortical gray matter. Establishing the utility of this relatively new quantitative SPECT technique provides an important tool for the management of vascular disorders of the brain. Additionally, identifying the site-specific effects of cocaine provides targets for the development of putative therapeutic medications to attenuate or minimize ischemic stroke in cocaine addicts.

Isradipine prevents global and regional cocaine-induced changes in brain blood flow: a preliminary study

The L-type calcium channel antagonist, isradipine, reduces brain ischemia in animal models of ischemic stroke. These effects of isradipine appear more pronounced in dopamine (DA) rich brain regions. These same DA-rich brain regions have also been shown to be the areas most affected by cocaine-induced ischemic changes. Using a novel quantified approach to single photon emission computerized tomography, we demonstrated that isradipine pre-treatment prevented cocaine-induced ischemic changes, especially in these DA-rich brain regions. This is the first demonstration that any medication, including isradipine, can prevent the ischemic effects of cocaine on brain blood flow. Isradipine may, therefore, be a useful therapeutic agent for the prevention of brain ischemia in cocaine addicts.

Augmented enterocystoplasty for neurogenic bladder associated with renal transplantation: appearance on Tc-99m MAG3 renal transplant scan

Enterocystoplasty (bladder augmentation) is a method of increasing bladder capacity in patients with small or neurogenic bladders in order to prevent vesicoureteral reflux. In patients with poorly compliant bladders, enterocystoplasty, which consists of a segment of detubularized small bowel or a portion of the stomach attached to the bladder, often helps to reduce the intravesicular pressures, thus reducing the likelihood of infection. It is also useful in treating bladder dysfunction in children with end-stage renal disease who require renal transplantation. Radiographic evaluation of patients with a renal transplant and augmented bladder often can be confusing, and may suggest a urine leak or hematoma. We report a patient with a renal transplant, bladder augmentation, and rising serum creatinine who underwent renal scintigraphy and ultrasonography.

Major histocompatibility complex class II antigen expression in rejecting cardiac allografts: detection using in vivo imaging with radiolabeled monoclonal antibody

BACKGROUND

Increased expression of major histocompatibility complex class II (MHC-II) antigen occurs during cardiac allograft rejection. We tested the hypotheses that (1) radiolabeled antibody to MHC-II antigen allows detection of cardiac allograft rejection using nuclear imaging techniques and (2) uptake of radiolabeled antibody to MHC-II antigen correlates with severity of rejection.

METHODS AND RESULTS

Thirteen beagles with cervical cardiac allografts were studied for 64+/-23 days by use of myocardial biopsy and in vivo imaging. Uptake of radiolabeled (131I [n=2], 123I [n=1], or 111In [n=10]) antibody to MHC-II increased over baseline in 7 animals that developed histological evidence of progressively worsening allograft rejection (group A), from 72.2+/-46.1 to 176.8+/-102.0 counts/pixel/mCi (P<.009). In 4 beagles without progressively worsening allograft rejection (group B), uptake was unchanged during follow-up (74.4+/-43.8 and 60.2+/-37.4 counts/pixel/mCi; P=NS). In animals studied with 111In-labeled antibody, uptake increased from 102.9+/-23.1 at baseline to 233.2+/-82.7 counts/pixel/mCi at follow-up in group A animals (P=.036), with no significant change in group B (91.1+/-34.9 and 75.9+/-24.9 counts/pixel/mCi; P=NS). Uptake of 111In-labeled antibody was 107.5+/-35.7, 135.9+/-70.8, and 307.8+/-90.1 counts/pixel/mCi in biopsy samples showing evidence of mild, moderate, and severe rejection, respectively (P=.001). Biopsy samples showing mild, moderate, and intense MHC-II expression antibody uptake had uptakes of 92.6+/-36.3, 158.5+/-54.7, and 307.8+/-90.1 counts/pixel/mCi, respectively (P=.00004).

CONCLUSIONS

Radiolabeled monoclonal antibodies to MHC-II antigen can detect cardiac allograft rejection in this large mammal model of cardiac allograft transplantation, and this technique may have a potential role in the detection of rejection in patients after cardiac transplantation.

Demonstration of hypoperfusion surrounding intracerebral hematoma in humans

We undertook this study to determine whether ischemic regions are present that may contribute to poor outcome after intracerebral hemorrhage (ICH) in humans. Hypoperfusion around an ICH has not been reported in humans. Brain computed tomography (CT) and (99m)Tc-HMPAO brain single photon emission computed tomography (SPECT) perfusion studies were carried out 51 +/- 12 hours after supratentorial ICH in seven patients selected from a referral hospital over an 8-month period. The widest diameters of the hematoma on CT and of reduced perfusion on SPECT were measured and compared. The diameters of reduced perfusion were measured at the 40% and 20% reduced count levels compared with the contralateral side. Reduced perfusion in and around the hematoma was seen in all seven cases. The diameters of ICH on CT (mean, 53 +/- 12 mm) were comparable to the diameters of 40% reduction of counts (mean, 61 +/- 14 mm) measured by SPECT. The mean diameter of brain demonstrating 20% reduction in counts was 76+/-19 mm, which was 43% greater than the hematoma diameter on CT (p = .004). In conclusion, substantial regions of reduced perfusion surround ICH in humans, which might contribute to poor outcome and be amenable to anti-ischemic therapy.

Prominent small bowel Ga-67 uptake associated with Yersinial and tuberculous enterocolitis

The nuclear medicine evaluation of the immunocompromised patient with fever of unknown origin may include the use of either labeled leukocytes or Ga-67 citrate, or both, in the search for an infectious focus. In recent years, labeled leukocytes (In-111 or Tc-99m) seem to have been employed preferentially by some. This is especially the case when the abdomen is a suspected site of involvement because of the normal colonic excretion of gallium that may complicate the interpretation of this study. The authors present the case of an immunocompromised patient with the interesting scintigraphic pattern of diffuse large and small bowel uptake of gallium secondary to biopsy proven Yersinia and tuberculous enterocolitis. A review of the recent literature reveals only one other similar case in which Yersinial disease was detected by Ga-67 scintigraphy. The present case illustrates that gallium's avidity for the atypical, less pyogenic, opportunistic infections common in immunocompromised patients justifies its continued use in such settings and, specifically, whenever tuberculosis is suspected.

Scintigraphic manifestations of "sternal cupping"

Sternal abnormalities in sickle-cell disease have been documented by bone scintigraphy and radiography in patients with homozygous sickle-cell anemia, but not in patients with sickle-thalassemia. We present here two unusual cases of sternal abnormalities in complicated sickle-cell disease. One is an infant with radiographic findings of "sternal cupping" and transient hypo-ossification of the sternum and sickle-thalassemia. The other patient is also a male infant with unusual, persistent under-ossification of bone, in association with radiographic findings of "sternal cupping." The second patient also had a 4P-chromosomal defect (Wolf-Hirschhorn syndrome) in which sternal hypo-ossification was described.

Clinical pharmacology, metabolism, and tissue distribution of 90Y-labeled monoclonal antibody B72.3 after intraperitoneal administration

B72.3 is a murine monoclonal antibody that recognizes a high-molecular-weight tumor-associated glycoprotein (TAG-72). Nine patients with TAG-72-positive ovarian carcinoma or papillary serous carcinoma of the peritoneum received an intraperitoneal infusion of 2, 4, or 10 mg B72.3 labeled with 0.5-1.2 (mean, 0.8) mCi 90Y. All patients had laparotomy, with multiple tissue and tumor samples removed 3-7 days later. The concentration of the total 90Y label in peritoneal fluid cleared with an extrapolated half-life of 68.6 +/- 4.5 hours. A low-molecular-weight 90Y-labeled species of metabolite was identified by high-performance liquid chromatography. The concentration of this low-molecular-weight species initially increased in the peritoneal fluid, with a half-life of 0.9 hour, and was rapidly cleared from the peritoneal cavity, with a half-life of 23.1 hours. Both the 90Y-labeled metabolite and the 90Y-labeled B72.3 were absorbed into the plasma, with half-lives of 16 +/- 2.2 hours and 25 +/- 5 hours, respectively. The clearance half-lives for these agents in plasma were 25 +/- 3 hours for the metabolite and 42 +/- 17 hours for B72.3. Approximately 8%-11% of the total injected 90Y label appeared in urine over 72 hours. Most of the label (about 70%) was present as the 90Y-labeled metabolite, but about 30% of the 90Y label in urine appeared identical to the authentic 90Y-labeled B72.3 standard when assayed by chromatography. Tissue distribution studies showed that normal tumor tissue and omentum contained the highest content of 90Y (about 0.017% of the injected dose per gram), followed in descending order by liver, normal lymph nodes, peritoneum, bone, and fascia. The lowest concentrations of 90Y were found in rectus abdominis muscle, bone marrow, and fat. There was substantial heterogeneity in the uptake of the 90Y label into tumor sites among patients and among different sites within the same patient. No correlation could be demonstrated between the TAG-72 content and the amount of 90Y label found in tumor sites. Preliminary radiation dosimetry estimates suggest that the tumor sites received about 82.8 cGy for each millicurie of 90Y administered. Thus, if an adequate total radiation dose can be achieved, 90Y-labeled B72.3 should be therapeutically useful for treating diffuse intraperitoneal disease.

Regression of hepatic metastases from gastrointestinal leiomyosarcoma after hepatic arterial chemoembolization

Two patients with gastrointestinal leiomyosarcoma metastatic to the liver were treated by hepatic chemoembolization with cisplatin and polyvinyl sponge followed by hepatic arterial infusion of vinblastine. Effective palliation in terms of durable tumor regression was achieved in both patients after two chemoembolization-infusion procedures. These results suggest that regional therapy may offer new hope for the subset of sarcoma patients who have liver metastases resistant to combination systemic chemotherapy.

Sequential use of indium-111 labeled monoclonal antibodies 96.5 and ZME-018 does not increase detection sensitivity for metastatic melanoma

Two indium-111 labeled anti-melanoma murine monoclonal antibodies (MAb), 96.5 and ZME-018, each recognizing separate antigens on melanoma cells, were administered intravenously to 17 patients with melanoma in a sequential fashion to determine whether: 1) additional tumor sites could be imaged with the combination compared to a single Mab; 2) the first MAb influenced the biodistribution and tumor localization of the second; and 3) significantly toxicity occurred with the combination. Patients were randomized to receive either 96.5, followed by ZME-018, ZME-018 followed by 96.5, or each MAb followed by itself (controls). Infusions of the second MAb occurred 10 days after the first infusion. Gamma camera images were obtained 72 hours after each antibody infusion. There were 139 known metastatic sites of which 72 lesions were localized by either MAb for an overall sensitivity of 52%. The detection rate was higher when lesions only greater than 1.5 cm were considered. Imaging results were independent of MAb administration sequence. When ZME-018 was given as the first infusion, when ZME-018 was given as a second infusion (p = NS). However, mean sensitivities using 96.5 as the first or second infusion were 48% and 66% respectively (p = NS). There was not a significant number of sites detected by MAb 2 that were missed by MAb 1. Human anti-murine antibody (HAMA) response occurred in seven of eight patients studied; two patients who experienced toxicity had levels of HAMA greater than 2000 ng/ml. We conclude that the use of these two murine anti-melanoma monoclonal antibodies given in sequential fashion did not significantly change the imaging sensitivity from that seen with each individual antibody. Moreover, with the exception of one patient, mean plasma half-life of the MAb did not change significantly, suggesting that overall clearance mechanisms were not saturated by the consecutive doses of monoclonal antibody or significantly altered by the presence of HAMA.

Comparative clinical pharmacology of [111In]-labeled murine monoclonal antibodies

Patients with metastatic melanoma received either the murine antimelanoma antibody ZME-018 (20 patients) or antibody 96.5 (26 patients) at doses ranging from 1 to 20 mg and coupled to 2.5 or 5 mCi of [111In]. The pharmacokinetics and tissue disposition of these antibodies were measured at various times after infusion of the radiolabel. The clearance of the [111In]label from plasma closely fit (r2 greater than 0.90) an open, one-compartment mathematical model after administration of antibody 96.5. Clearance of [111In] from plasma after administration of ZME-018 fit a one-compartment model in some patients and a two-compartment model in others. The terminal phase half-lives of 96.5 and ZME-018 antibodies at the 20-mg dose were almost identical (27 +/- 2 h and 29 +/- 5 h, respectively). The half-lives calculated for 96.5 were not dependent upon the total antibody dose; however, with increasing doses of ZME-018 there was a dose-dependent increase in t 1/2 (from 17.8 +/- 2 h at the 2.5-mg dose to 29 +/- 5 h at the 20-mg dose). For 96.5 antibody, the apparent volume of distribution (Vd) approximated the total blood volume (7.8 +/- 0.71) at the 1-mg dose and decreased significantly at the 20-mg dose, suggesting saturation of extravascular antigen sites. In contrast, the Vd calculated for ZME-018 did not appear to be dependent upon the administered dose. Improved imaging occurred with increasing doses of unlabeled 96.5 above 2 mg, a finding not observed with ZME-018. The cumulative urine excretion of [111In] after administration of 96.5 or ZME-018 was 10%-14% of the total dose. These studies show that murine monoclonal antibodies of the same subtype but recognizing different surface antigens can exhibit markedly different in vivo pharmacokinetic behavior, which may partially explain differences in imaging noted with increasing doses of monoclonal antibody.

Clinical parameters related to optimal tumor localization of indium-111-labeled mouse antimelanoma monoclonal antibody ZME-018

Radioimmunolocalization of an 111In-labeled mouse antimelanoma monoclonal antibody (MoAb), ZME-018, was examined in 21 patients with metastatic malignant melanoma. Each patient received a single. i.v. infusion of MoAb at concentrations ranging from 1 mg to 20 mg, coupled to 5 mCi 111In by the chelating agent DPTA. No toxicity was observed in any patient. Total-body and regions of interest scans performed at 4, 24, and 72 hr following MoAb administration revealed uptake in 63 out of 105 previously diagnosed metastases for an overall sensitivity of 60%. Uptake was consistently observed in liver/spleen, and less frequently in bowel, testes, axillae and bone. Sensitivity of detection increased significantly at doses of MoAb above 2.5 mg, with 74% of lesions imaging at 20 mg/5 mCi compared with 29% at 2.5 mg/5 mCi (p less than 0.005). A significant correlation was observed between tumor uptake of 111In-MoAb conjugate and increasing tumor size. Soft-tissue lesions such as skin and lymph node metastases were imaged to a greater extent (76%) than visceral metastases (19%). In five of six patients, biopsies obtained from 3 days to 14 days after MoAb administration showed antibody present on tumor cells as demonstrated by flow cytometry and/or radioimmunoassay. Human anti-murine immunoglobulin responses were observed in seven of 17 patients studied. Mean plasma clearance of ZME-018 was prolonged with a T1/2 of 24.7 hr and increased slightly with increasing MoAb dose. Urinary excretion of 111In averaged 12.4% of the injected dose over 48 hours. Radioimmunolocalization of melanoma with 111In-labeled ZME-018 appears feasible. The sensitivity of the technique was related to dose, tumor size, and disease site.

Effect of non-steroidal anti-inflammatory drugs on control of hypertension by beta-blockers and diuretics

The effect of sulindac on renal function and blood pressure was compared with those of placebo, piroxicam, and naproxen in 20 patients with primary hypertension being treated with a diuretic and a beta-blocker. Although the three non-steroidal anti-inflammatory drugs (NSAIDs) did not differ in their effect on renal function (weight, glomerular filtration rate, creatinine clearance) or on serum thromboxane and plasma 6-keto prostaglandin F1 alpha (6-keto PGF1 alpha), blood pressure was significantly lower with sulindac than with placebo, piroxicam, or naproxen. These differences were associated with less renal cyclooxygenase inhibition by sulindac (reflected by urinary thromboxane B2 and 6-keto PGF1 alpha) than by other NSAIDs. The findings suggest that the blood pressure differences reflect vasodilation due to differences in the balance between systemic and renal effects of the NSAIDs.

Reduction by morphine of human postprandial insulin release is secondary to inhibition of gastrointestinal motility

The effect of morphine (0.1 mg/kg) on insulin secretion stimulated by oral, intraduodenal, or intravenous administration of glucose was studied in seven healthy volunteers. When glucose was given intravenously, morphine had no effect on plasma glucose, insulin, glucose-dependent insulinotropic polypeptide (GIP), or pancreatic glucagon. Following oral glucose, morphine slowed gastric emptying and reduced plasma concentrations of glucose, insulin, and GIP. During intraduodenal infusion of glucose, insulin concentrations in plasma were also decreased by morphine, an effect best explained by decreased small intestinal transit with delayed absorption of glucose and delayed release of GIP. We conclude that clinically relevant doses of morphine have no direct effect on insulin secretion and that the changes observed were secondary to slowed gastric emptying and small intestinal transit.

Differential glomerular filtration rate in diagnosis of renovascular hypertension and follow-up of balloon angioplasty

Two hundred nine hypertensive patients with high stimulated plasma renin levels were screened for renovascular hypertension using Tc-99m DTPA renal scintigraphy. Differential glomerular filtration rate (Diff-GFR) was obtained by integrating the area under the background-subtracted renogram of each kidney between 1 and 3 minutes. 50 patients who also had undergone selective renal angiography were divided into four groups according to Diff-GFR contribution by one of the kidneys. If one kidney contributed 45-50% of total GFR, this was regarded as normal. A Diff-GFR of less than 45% was very considered to be very suggestive of renovascular hypertension in the appropriate clinical setting, while a Diff-GFR of less than 20% indicated that the renal artery might not be amenable to successful balloon angioplasty. Diff-GFR following balloon angioplasty closely reflected the early clinical response of the patients--and in some cases progressive Diff-GFR improvement was observed several months later. Diff-GFR as a scintigraphic criterion for renovascular hypertension has a sensitivity of 93%, specificity of 74%, and accuracy of 85%.

Radioimmunoimaging in malignant melanoma with 111In-labeled monoclonal antibody 96.5

A radiolabeled monoclonal antibody (96.5) reactive with an Mr 97,000 antigen found on over 80% of melanoma cell lines and tissue extracts was examined for its ability to detect malignant melanoma metastases in vivo. For imaging purposes, it was conjugated with diethyltriaminepentaacetic acid and subsequently labeled with 111In by chelation. Thirty-one patients with metastatic melanoma received single injections of monoclonal antibody 96.5 at concentrations ranging from 0.5 to 20 mg and at specific activities of 111In ranging from 0.125 to 4 mCi/mg. Total-body scans were performed at various time intervals following administration. No serious side effects were observed. Of a total of 100 previously documented metastatic sites, 50 imaged for a specificity of 50%. The number of sites imaged increased significantly as the amount of antibody administered increased relative to the average radiation dose. Considerable background uptake of isotope was observed in blood pool and other organs with gradual acquisition of label in tumor sites by 48 to 72 h. Hence, tumor imaging of melanoma using 111In-labeled monoclonal antibody 96.5 appeared feasible, especially at antibody doses above 2 mg.

Baker's cyst. Radionuclide arthrographic findings

Radionuclide arthrography of the knee is described using Tc-99m sulfur colloid, which is injected into the synovial cavity following partial distension of the joint space with saline. The preliminary findings in Baker's cyst are described. There appear to be four patterns: 1) a herniation or cyst that can be posterior, inferior, medial or lateral to the knee synovial space; 2) a limited leak inferiorly toward the calf or superiorly toward the thigh; 3) extensive leak: giant cyst found in patients with rheumatoid arthritis; 4) multiple "cysts" or communications with the knee synovial space. The series is small, and more work is needed before these preliminary findings can be used as firm categories. Radionuclide arthrography should be considered in patients with unexplained calf pain or pain behind the knee, especially with a history of previous internal knee derangement, or rheumatoid arthritis in whom ruptured cysts can closely mimic acute thrombophlebitis. Radionuclide arthrography has certain advantages over contrast arthrography and also arthroscopy in the diagnosis of Baker's cyst.

A study of gastrointestinal opiate receptors: the role of the Mu receptor on gastric emptying: concise communication

Animal and in vitro experiments suggest that opiates exert their actions by interaction with possibly five different subtypes of opiate receptors, identified as mu, kappa, sigma, delta, and epsilon. As yet there is no conclusive evidence for their existence in man. Our experiments on morphine and the enkephalin analog DAMME have suggested at least two types of opiate receptors involved in gastric secretion. In this study we have used the very powerful and nonselective opiate agonist etorphine to stimulate as many of the different opiate receptors as possible. We have then attempted to block selectively the mu receptor by administering a small dose of naloxone. Etorphine delayed gastric emptying whereas naloxone alone had no effect. In combination, the inhibitory effect of etorphine on gastric emptying was incompletely prevented while the subjective effects of etorphine were completely abolished. These results may indicate that mu receptors are important in the regulation of gastric emptying, but that other (non-mu) receptors are also involved. The radionuclide study of gastric emptying, as used here, is a potentially powerful tool in physiological research on the gastrointestinal tract.

The effect of a synthetic enkephalin analogue on postprandial gastrointestinal and pancreatic hormone secretion

The effect of the synthetic enkephalin analogue Sandoz FK33-824 (DAMME) on gastric emptying and the postprandial secretion of upper gastrointestinal and pancreatic hormones was investigated in six healthy subjects. Gastric emptying was delayed as was the postprandial rise in glucose. There was significant blunting of insulin and gastric inhibitory polypeptide secretion, with complete abolition of the normal postprandial increases in pancreatic polypeptide and motilin. The secretion of gastrin was prolonged. These results demonstrate that pharmacological doses of opiate peptides inhibit gastric emptying and may have direct and indirect effects on gastrointestinal and pancreatic hormone secretion.

Malignant pleural effusion and Tc-99m MDP accumulation

Two case reports of malignant pleural effusion from breast carcinoma, with scans showing a striking accumulation of Tc-99m MDP, are presented. The Tc-99m MDP was in the pleural fluid and not in the pleura as demonstrated by shift with gravity. Possible mechanisms of malignant effusion accumulation of Tc-99m MDP are suggested. The scant literature on the subject is reviewed.