Localizing infection with a technetium-99m-labeled peptide: initial results.

In vitro-labeled leukocyte imaging is useful for the detection of infection, but an in vivo labeling method is preferable. This study sought to evaluate the safety and efficacy of a leukocyte-avid peptide for the detection of infection, to determine the effects of peptide dose on performance and to compare the peptide with in vitro-labeled leukocytes. A 23-amino acid peptide, P483, containing the platelet factor-4 heparin-binding sequence, was labeled with 99mTc and complexed with heparin (P483H). Thirty patients were injected with 29 microg (n = 11), 145 microg (n = 10) or 290 microg (n = 9) of labeled peptide, and imaged 15 min and 90-120 min later. Early and late images were interpreted individually and jointly. Twenty patients underwent (111)In-labeled leukocyte scintigraphy. Fourteen patients had infection: osteomyelitis (n = 7), vascular graft (n = 2), abscess (n = 2), joint replacement (n = 1), surgical wound (n = 1) and pneumonia (n = 1). There were 10 adverse events in six patients; all were mild and resolved spontaneously, and without any intervention. The sensitivity, specificity and accuracy were the same for both early and late imaging: 0.86, 0.81 and 0.83, respectively. Interpreting early and late images together did not improve the results. No relationship between peptide dose and study accuracy was found. In patients undergoing both examinations, the accuracies of the peptide and in vitro-labeled leukocyte imaging were identical: 0.80. In summary, 99mTc-P483H safely, rapidly and accurately detected focal infection, was comparable with in vitro-labeled leukocyte imaging and therefore merits further investigation.

Optimizing images of acute deep-vein thrombosis using technetium-99m-apcitide.

OBJECTIVE: The purpose of this paper is to introduce the nuclear medicine technologist to a new radiopharmaceutical, 99mTc-apcitide, for imaging acute venous thrombosis. After reading this paper, the technologist should be able to: (a) describe patient preparation for imaging with 99mTc-apcitide; (b) state the amount of 99mTc-apcitide that is administered to patients for imaging acute venous thrombosis; (c) explain patient positioning for optimal image acquisition; and (d) discuss gamma camera acquisition parameters and their importance in obtaining high-quality images. Clinical cases illustrate both the whole-body distribution and diagnostic value of 99mTc-apcitide in detecting acute deep-vein thrombosis.

Upper extremity radionuclide bone imaging: the wrist and hand.

Bone scintigraphy of the hands and wrists represents an important adjunct imaging technique that complements plain film radiographic examination. The use of the three-phase bone scan provides clinical information not only regarding osseous uptake but the blood flow and extravascular distribution of the radiotracer as well. Scintigraphic evaluation of the hands and wrists is employed in acute and chronic conditions. In the event of an equivocal or negative plain film, the bone scan can identify occult fractures. Of particular concern is the identification of scaphoid fractures due to the higher incidence of osteonecrosis. Work related injuries represent a significant health issue. The bone scan can be a part of the algorithm for evaluating chronic pain syndromes including reflex sympathetic dystrophy. The complimentary roles of bone scanning and imaging with gallium-67 citrate or radiolabeled leukocytes has proven useful in the evaluation of acute or chronic osteomyelitis. In addition, the diphosphonates are useful in identifying solitary and multiple primary bone tumors. In the case of primary bone tumor, thallium-201 can be used to evaluate response to therapy. Although uncommon in the hand and wrist, the bone scan can identify metastatic tumors or tumor-related conditions such as hypertrophic osteoarthropathy. Finally, bone scintigraphy may be useful in identifying location and extent in a variety of conditions such as fibrous dysplasia, histiocytosis X, and Paget's disease.

Bone pain and radionuclide therapy.

The Council on Scientific Affairs of the California Medical Association presents the following epitomes of progress in nuclear medicine. Each item, in the judgment of a panel of knowledgeable physicians, has recently become reasonably firmly established, both as to scientific fact and clinical importance. The items are presented in simple epitome, and an authoritative reference, both to the item itself and to the subject as a whole, is generally given for those who may be unfamiliar with a particular item. The purpose is to assist busy practitioners, students, researchers, and scholars to stay abreast of progress in medicine, whether in their own field of special interest or another. The epitomes included here were selected by the Advisory Panel to the Section on Nuclear Medicine of the California Medical Association, and the summaries were prepared under the direction of Dr Lyons and the panel.

Nuclear medicine approaches to musculoskeletal disease. Current status.

With the advent of bone scintigraphy, physicians achieved earlier detection of metastatic disease. In the prior two decades, bone imaging has expanded into the realm of tomography (SPECT, PET), and diverse clinical applications, including trauma, grafts, benign disease, and tumor imaging.

Assessment of left ventricular ejection fraction from technetium-99m-methoxy isobutyl isonitrile multiple-gated radionuclide angiocardiography.

Abnormal left ventricular function is a diagnostic indication of cardiac disease. Left ventricular function is commonly quantified by ejection fraction measurements. A novel approach for the determination of left ventricular ejection fraction from technetium-99m-methoxy isobutyl isonitrile multiple-gated radionuclide angiocardiography is presented. Data from 23 patients, symptomatic of cardiac disease, indicate that ejection fractions determined using the radionuclide technique correlate well with contrast X-ray single-plane cineangiography (r=0.83, p<10(-6)). Data from 14 of the patients indicate favorable correlation with technetium-99m-pertechnetate gated blood pool radionuclide angiocardiography (r=0.87, p<10(-4)).

Thallium-201 scintigraphy after intravenous infusion of adenosine compared with exercise thallium testing in the diagnosis of coronary artery disease.

Adenosine is an endogenously produced compound that has significant effects as a coronary and systemic vasodilator. Previous studies suggest that intravenous infusion of adenosine, coupled with thallium-201 scintigraphy, may have specific value as a noninvasive means of evaluating coronary artery disease. The purpose of this study was to compare the diagnostic value of adenosine thallium testing with that of standard exercise thallium testing. One hundred subjects were studied with exercise thallium imaging and thallium imaging after adenosine infusion, including 47 with angiographically proved coronary artery disease and 53 control subjects. The overall sensitivity of the thallium procedures was 81% for the exercise study and 83% for the adenosine study (p = NS); the specificity was 74% for the exercise study and 75% for the adenosine study (p = NS). The diagnostic accuracy of the exercise study was 77% and that of the adenosine study was 79%. Ninety-four percent of subjects had an adverse effect due to the adenosine infusion; however, most of these effects were mild and well tolerated. All adverse effects abated within 30 to 45 s of the termination of the study, consistent with the very brief half-life of the agent. Thus, thallium-201 scintigraphy after intravenous infusion of adenosine has a diagnostic value similar to that of exercise thallium testing for evaluation of coronary artery disease. Adenosine thallium testing may be particularly useful in evaluating patients unable to perform treadmill exercise testing.

The value of urine creatinine analysis in the evaluation on Schilling tests.

We performed a prospective study to assess the clinical value of evaluating the adequacy of 24-hour urine specimens submitted for Schilling tests. A total of 121 specimens were evaluated of which 51 had abnormal vitamin B12 excretion values. Of those 51, there were 23 with apparently inadequate total creatinine content (implying a collection of less than 24 hours). Six of 12 specimens with less than 600 ml had adequate total creatinine content as well as normal vitamin B12 excretion. Compared with evaluation of specimen volume alone, these data support the inexpensive urine creatinine assay as a valuable source of information regarding the adequacy of 24-hour urine collections thereby improving the specificity of the Schilling test.

Usefulness of ambulatory radionuclide monitoring of left ventricular function early after acute myocardial infarction for predicting residual myocardial ischemia.

Ambulatory radionuclide monitoring of left ventricular function was performed with the nuclear Vest device in 35 patients early after acute myocardial infarction. Patients were evaluated during post-infarction treadmill, other activities that included mental stress and cold pressor challenge, and with stress thallium imaging and cardiac catheterization. Of the 35 patients evaluated, 14 had ischemic responses on treadmill testing and 21 had negative responses. By contrast, 20 had redistribution by thallium imaging suggesting ischemia. Vest studies demonstrated 56 responses suggestive of ischemia in 23 patients. Twenty-two occurred during exercise and 13 with mental stress. Seventy-five percent were silent and only 39% had associated electrocardiographic changes. Vest responses were compared in patients whose thallium scan was indicative of ischemia (thallium-positive) and those without ischemia (thallium-negative). Ejection fraction was higher in the thallium-positive group (0.52 +/- 0.11), as compared with thallium-negative patients (0.44 +/- 0.1). With exercise, ejection fraction decreased for the thallium-positive patients from 0.52 +/- 0.11 to 0.40 +/- 0.09 at peak exercise. For thallium-negative patients, ejection fraction changes were not significant. During mental stress, ejection fraction decreased from 0.51 +/- 0.11 to 0.45 +/- 0.12 for thallium-positive patients while thallium-negative patients were unchanged. Vest-measured decreases in ejection fraction of greater than or equal to 5 units during exercise were highly sensitive (90%), specific (73%) and predictive (82%) of a positive thallium scan. The same response for mental stress was specific (87%) and predictive (85%) of a positive scan result.(ABSTRACT TRUNCATED AT 250 WORDS)

Stress thallium-201 imaging after coronary angioplasty predicts restenosis and recurrent symptoms.

The predictive accuracy of thallium imaging for the diagnosis of restenosis after angioplasty was evaluated in 121 patients who had undergone a successful procedure. Patients were evaluated three times over a 1 year follow-up period for symptoms, electrocardiographic (ECG) changes during exercise and the presence of reversible ischemia on exercise thallium imaging. At initial evaluation (4 to 6 weeks after angioplasty), 104 patients (86%) were asymptomatic. Of the 17 patients with chest pain symptoms, 9 had reversible ischemia on thallium imaging and all had restenosis. Of the 104 asymptomatic patients, 26 (25%) had a positive thallium scan (reversible ischemia) and this sign identified a high risk group. Evidence of restenosis was present by 6 months in 22 (85%) and by 1 year in 25 (96%) of these 26 patients. The largest group of patients manifested symptoms by the second evaluation (between 3 and 6 months after angioplasty). Of 28 patients with symptoms and a positive thallium scan at this evaluation, 26 had restenosis; on initial evaluation, 22 of these 26 patients had no symptoms but had had a positive thallium study. Ten of the 65 patients in the asymptomatic group had a positive thallium scan, but the scans of this group were not as predictive for recurrent symptoms as were those of the same group at initial evaluation. The 74 patients who had a negative thallium scan at 3 to 6 months with or without associated symptoms had a low likelihood of developing restenosis or symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Early osteonecrosis of the femoral head: detection in high-risk patients with MR imaging.

To determine whether magnetic resonance (MR) imaging can demonstrate the early stages of osteonecrosis that are not detectable radiographically, the authors compared radiologic findings with histologic results in seven patients at high risk for osteonecrosis of the femoral head. Radiography and MR imaging were performed, and proximal femoral intramedullary pressures were measured in all patients, even if results from imaging studies were normal. If the pressures were elevated, core decompression with biopsy was performed. Seven patients had elevated pressures in 11 hips. Of 11 hips from which biopsy specimens were taken, all had histologic evidence of osteonecrosis. However, in only five were the MR imaging findings consistent with osteonecrosis. In the remaining six hips with osteonecrosis, MR imaging findings were normal. Sensitivity of MR imaging in detection of osteonecrosis was 46%. The authors conclude that normal MR imaging results in high-risk patients do not rule out the presence of osteonecrosis.

Prevention of motion artifacts on dual isotope subtraction parathyroid scintigraphy.

A simple, effective technique is described to identify and eliminate motion artifacts which might potentially invalidate dual isotope subtraction parathyroid scintigraphy. Cobalt-57 markers, appropriately placed on the patient, allow detection of movement and permit realignment if movement occurs between imaging sequences. This technique should assure the accuracy of dual isotope parathyroid subtraction scintigraphy.

Gastroesophageal reflux demonstrated by hepatobiliary imaging in scleroderma.

Radionuclide hepatobiliary imaging was performed on a patient with a longstanding history of scleroderma who presented with abdominal pain suggestive of biliary disease. Cystic duct patency was documented after 10 min with tracer accumulation in the second portion of the duodenum which failed to progress consistent with the duodenal hypomotility of scleroderma. The patient was given intravenous Kinevac resulting in gastroesophageal reflux of radionuclide.

Parotid gland biopsy and 67Ga imaging correlation in systemic sarcoidosis.

We correlated the results of parotid gland biopsy, chest roentgenograms, and gallium citrate scintigraphy in 24 patients evaluated for possible systemic sarcoidosis. Of 19 patients ultimately proven to have sarcoidosis, 11 (57.9 percent) had positive parotid gland biopsy. The yield of parotid gland biopsy in patients with abnormal gallium parotid activity was only marginally higher (64.7 percent). Abnormal parotid gland uptake of gallium citrate was seen in 17 of these 19 patients (89.5 percent) and was always associated with abnormal lung or perihilar activity. The parotid gland biopsy is a useful technique for obtaining the tissue diagnosis of sarcoidosis; however, gallium scintigraphy should not be performed to select patients as this will only marginally increase the biopsy yield.

Technetium-99m red blood cell blood-pool imaging in functional asplenia due to leukemic infiltration.

Tc-99m labeled RBC blood-pool and Tc-99m sulfur colloid imaging were performed in a patient with chronic myelogenous leukemia (CML) in blast crisis. Functional asplenia was demonstrated on the sulfur colloid study despite intact organ perfusion as demonstrated by blood-pool imaging. Tc-99m RBC blood-pool imaging appears to be an ideal noninvasive technique to document intact spleen perfusion in functional asplenia.

Reversibility of long-standing left ventricular aneurysm predicted by thallium-201 imaging.

Stress thallium-201 perfusion scintigraphy was used to assess the reversibility of a long-standing left ventricular aneurysm. By identifying reversible ischemia, it was predicted that this patient's ventricular function would benefit significantly from surgical revascularization or percutaneous transluminal coronary angioplasty.

Segmental coronary artery disease: detection by rotating slant-hole collimator tomography and planar thallium 201 myocardial scintigraphy.

Normal quantitative circumferential profile limits were established for a 30 degrees bilateral rotating slant-hole (RSH) collimator tomographic system. This system's value in detecting segmental coronary artery disease was assessed in a study evaluating 196 patients by thallium 201 myocardial scintigraphy and coronary arteriography. Profile curves were calculated from images of 20 healthy patients and used to identify significant coronary artery disease (greater than or equal to 70% diameter narrowing) in the left anterior descending (LAD), the right, and the left circumflex (LCx) coronary arteries. In a group of 86 patients, an abnormality on the apical or middle plane optimally identified segmental coronary artery disease. When such abnormalities were prospectively evaluated in a test group of 110 patients, the sensitivity and specificity were 79% and 93% for LAD, 90% and 90% for right, and 83% and 83% for LCx coronary artery disease. Compared with qualitative interpretation of the planar and tomographic images, quantitative tomography significantly improved the sensitivity of T1-201 imaging in detecting LAD, right, and LCx coronary artery disease (P less than .001) in patients with or without previous myocardial infarction.

Thyroid uptake and imaging with iodine-123 at 4-5 hours: replacement of the 24-hour iodine-131 standard.

A study was carried out to determine the suitability of utilizing a 4 to 5 hr interval from administration of iodine-123 to imaging and uptake measurement as a replacement for the 24-hr standard originally established with iodine-131. In 55 patients who underwent scintigraphy at 4 and 24 hr, there was no discrepancy between paired images. In 55 patients who had uptake measured at 4 and 24 hr and in 191 patients who had uptake measured at 5 and 24 hr, the early measurements proved equal or better discriminants of euthyroid from hyperthyroid patients. In our institutions, these findings and the logistical advantages of completing the exam in 4-5 hr led us to abandon the 24-hr study in the majority of patients.