OBJECTIVE:Renographies obtained within 1 h of renal transplantation were studied prospectively to evaluate their technical feasibility and potential clinical impact on successful treatment of immediate posttransplantation complications such as arterial or venous thrombosis, which require prompt diagnosis and management.SUBJECTS AND METHODS:During December 1996 to December 1998, 127 renal transplants were performed. Ninety-four patients had complete renographic studies within 1 h of surgery. It was not possible to perform renography on 26 patients who were not sent to the Department of Nuclear Medicine within 1 h of transplant and 7 other patients who could not undergo a complete renogram because of their postoperative condition.RESULTS:There was no complication attributed to transporting patients to the Department of Nuclear Medicine for these studies so soon after surgery. Of the 94 renographies obtained immediately following transplant surgery 46 were abnormal. However, when compared with the usual policy of obtaining baseline renograms between 12 and 72 h after surgery, treatment was changed for only 2 patients. Radionuclide renography within 1 h of transplant surgery was technically feasible.CONCLUSION:Based on the results of this study the clinical utility of obtaining renography within 1 h posttransplant was minimal and hence we recommended that it should not be performed routinely but could be used on an individual basis when imminent intervention is highly likely.

OBJECTIVE:To determine the impact of three-phase bone scintigraphy (TPBS) on the diagnosis and management of complex regional pain syndrome type I (CRPSI) or reflex sympathetic dystrophy (RSD).SUBJECTS AND METHODS:Twenty consecutive patients with a recent clinical evidence of CRPSI were referred for TPBS as part of their routine management plan. All patients underwent neurological examinations with special attention to the evaluation of clinical features of vasomotor, sudomotor, motor and sensory dysfunction. Patients were followed prospectively. When both the clinical and TPBS results supported the diagnosis of CRPSI, patients were started on treatment.RESULTS:Of the 20 patients, TPBS supported the diagnosis of RSD in 9 who were treated with steroids and physiotherapy. Complete follow-up was available for 7 of them and all had a satisfactory response to treatment. For the remaining 11 patients RSD was diagnosed clinically but not confirmed by TPBS. On follow-up there was no evidence that TPBS failed to identify RSD in these 11 patients.CONCLUSION:The results indicate that TPBS confirmed the clinical diagnosis of RSD, and, more importantly, had a significant impact on its management.

Optimal technique for planar bone scanning improves image quality, which in turn improves diagnostic efficacy. Because planar bone scanning is one of the most frequently performed nuclear medicine examinations, maintaining high standards for this examination is a daily concern for most nuclear medicine departments. Although some problems such as patient motion are frequently encountered, the degraded images produced by many other deviations from optimal technique are rarely seen in clinical practice and therefore may be difficult to recognize. The objectives of this article are to list optimal techniques for 3-phase and whole-body bone scanning, to describe and illustrate a selection of deviations from these optimal techniques for planar bone scanning, and to explain how to minimize or avoid such technical errors.

OBJECTIVE:If additional chemicals are inadvertently introduced in the preparation of radiopharmaceutical kits, radiochemical impurities may be formed. We report our experience with erroneously diluting (99m)Tc-pertechnetate eluate with 5% dextrose solution rather than normal saline during the preparation of (99m)Tc-tetrofosmin, (99m)Tc-methylene diphosphonate (MDP), (99m)Tc-stannous colloid, and (99m)Tc-mebrofenin.METHODS:Scintigrams for 3 of the 4 radiochemicals unintentionally prepared with 5% dextrose were found to have an altered biodistribution. Therefore, radiopharmacy procedures for the day were reviewed, and instant thin-layer chromatography (ITLC) was performed.RESULTS:Scintigrams showed an altered biodistribution consistent with an impurity. Review of procedures that day uncovered the error of using 5% dextrose to dilute the (99m)Tc eluate. The altered biodistribution on (99m)Tc-stannous colloid, (99m)Tc-MDP, and (99m)Tc-mebrofenin scintigrams consisted of cardiac blood-pool activity (possibly as a result of slow clearance of (99m)Tc-dextrose), soft-tissue background activity (possibly as a result of interstitial distribution of (99m)Tc-dextrose), renal and bladder activity (possibly as a result of renal elimination of (99m)Tc-dextrose), and gallbladder activity (possibly as a result of hepatobiliary excretion of (99m)Tc-dextrose). Both scintigrams and ITLC showed no evidence of impurities for the (99m)Tc-tetrofosmin prepared using 5% dextrose.CONCLUSION:Unintended preparation of radiochemicals with 5% dextrose rather than normal saline often results in the production of impurities, possibly (99m)Tc-dextrose. Because some but not all commercial radiochemical kits prepared with 5% dextrose will suffer this fate, nuclear medicine physicians reviewing the day's images will be confronted with a confusing combination of expected and grossly abnormal findings.

Although bone scanning is a test primarily concerned with skeletal abnormalities, important nonosseous findings are occasionally present on the images. To gauge the significance of such nonosseous uptake and, in particular, to determine whether these findings contain useful diagnostic information, the technical and medical staff in nuclear medicine must recognize the various patterns of nonbony uptake and understand their causes. The objectives of this article are to demonstrate the appearances of nonosseous uptake on bone scans, to categorize the forms of soft-tissue uptake, to emphasize technical artifacts leading to soft-tissue uptake, and to highlight the clinical significance of pathologic soft-tissue uptake.

Although bone scanning is a test primarily concerned with skeletal abnormalities, important nonosseous findings are occasionally present on the images. To gauge the significance of such nonosseous uptake and, in particular, to determine whether these findings contain useful diagnostic information, the technical and medical staff in nuclear medicine must recognize the various patterns of nonbony uptake and understand their causes. The objectives of this article are to demonstrate the appearances of nonosseous uptake on bone scans, to categorize the forms of soft-tissue uptake, to emphasize technical artifacts leading to soft-tissue uptake, and to highlight the clinical significance of pathologic soft-tissue uptake.

A. Bone scintigraphy is a diagnostic study used to evaluate the distribution of active bone formation in the body. B. Whole-body bone scintigraphy produces planar images of the skeleton, including anterior and posterior views of the axial skeleton. Anterior and/or posterior views of the appendicular skeleton also are obtained. Additional views are obtained as needed. C. Limited bone scintigraphy records images of only a portion of the skeleton. D. Bone single-photon emission computed tomography (SPECT) produces a tomographic image of a portion of the skeleton. E. Multiphase bone scintigraphy usually includes blood flow images, immediate images, and delayed images. The blood flow images are a dynamic sequence of planar images of the area of greatest interest obtained as the tracer is injected. The immediate (blood pool or soft tissue phase) images include 1 or more static planar images of the areas of interest, obtained immediately after the flow portion of the study and completed within 10 min after injection of the tracer. Delayed images may be limited to the areas of interest or may include the whole body, may be planar or tomographic, and are usually acquired 2–5 h after injection. If necessary, additional delayed images may be obtained up to 24 h after tracer injection. III. Common Indications

Heterotopic ossification (HO) is the presence of bone in soft tissue where bone normally does not exist. The acquired form of HO most frequently is seen with either musculoskeletal trauma, spinal cord injury, or central nervous system injury. For example, patients who have recently undergone total hip arthroplasty or have paraplegia after spinal cord injury are at risk for HO. The fever, swelling, erythema, and occasional joint tenderness seen in early HO can be difficult to distinguish from cellulitis, osteomyelitis, or thrombophlebitis. Bone scanning and other imaging tests frequently are used to distinguish between these diagnostic possibilities. As treatment or prophylaxis for HO, either a nonsteroidal antiinflammatory drug (such as indomethacin), a diphosphonate (such as ethane-1-hydroxy-1,1-diphosphate), or local radiation therapy is recommended. Before therapy begins, bone scanning may be requested to confirm the diagnosis of HO. In addition, surgical resection of HO is used to preserve joint mobility; however, HO is likely to recur and possibly progress if resection is undertaken before the lesion has become mature. With a view toward avoiding recurrent HO and other operative complications, serial quantitative bone scans are used as an aid to time surgical intervention.

The diagnostic efficacy of (1) combined three-phase bone scintigraphy and In-111 labeled WBC scintigraphy (Bone/WBC), (2) MRI, and (3) conventional radiography in detecting osteomyelitis of the neuropathic foot was compared. Conventional radiography was comparable to MRI for detection of osteomyelitis. MRI best depicted the presence of osteomyelitis in the forefoot. Particularly in the setting of Charcot joints, Bone/WBC was more specific than conventional radiography or MRI.

Dynamic scintigraphy of a milk/technetium-99m sulphur colloid mixture or other radionuclidelabeled meal is a simple technique for demonstrating gastroesophageal reflux and/or aspiration. Since gastroesophageal reflux occurs intermittently and often is not associated with aspiration, the ability to monitor patients for long periods of time is a distinct advantage of the radionuclide technique. The technique is noninvasive, and no maneuvers are employed in an attempt to reduce reflux and/or aspiration. Therefore, the radionuclide method should be viewed as being physiologic. In pediatric populations, radionuclide studies performed in patients undergoing evaluation for pulmonary aspiration occurring both during swallowing (antegrade) or at the time of gastroesophageal reflux (retrograde) are well documented. Results, however, vary greatly from one institution to another, and the clinical utility of the examination in some pediatric populations has been questioned. Although favorable, only more preliminary results on both antegrade and retrograde aspiration in adult populations have been reported.

99Tc(m)-ECD is a new agent for perfusion brain imaging. Its brain retention is attributed to the enzymatic conversion of lipophilic 99Tc(m)-ECD to polar monoacid and diacid derivatives. Based on its proposed mechanism of retention in the brain, labelling of white blood cells (WBC) with 99Tc(m)-ECD has been studied at our laboratory. A labelling efficiency of 42% was achieved by incubating WBC with 99Tc(m)-ECD in phosphate buffered saline medium for 30 min. There was a washout of 50% of the radioactivity from the cells in 1 h, which might contribute to increased background in potential human studies. However, rapid urinary elimination of the radioactivity is expected to deal with this problem due to the rapid in vivo conversion of the parent compound to polar metabolites. 99Tc(m)-ECD appears to be a promising agent for labelling WBC. Furthermore, already prepared multidose 99Tc(m)-ECD may be used for either brain perfusion imaging or WBC labelling.

Twenty-two adult diabetic patients with clinical suspicion of foot and/or ankle infection were prospectively evaluated using radiography, technetium-99m methylene diphosphonate bone scanning (99Tc), indium-111-labeled leukocyte scanning (111In), and gallium-67 scanning (67Ga) to determine the presence of clinically suspected osteomyelitis. Biopsy for culture and histology was performed in 16 patients. The diagnosis of osteomyelitis was confirmed by biopsy in 12 patients. The remaining 10 patients had no evidence of osteomyelitis with long-term follow-up. 99mTc was snown to be of limited valued when used alone in these patients with peripheral neuropathy. 67Ga, either alone or in combination with 99mTc bone scanning, was of little diagnostic value and gave no additional information that was not available from 111In. The combination of three-phase 99mTc and 111In had the highest diagnostic efficacy (100% sensitivity, 80% specificity, and 91% accuracy), followed closely by 111In alone (100% sensitivity, 70% specificity, and 86% accuracy). We conclude that for adult diabetic patients with clinical suspicion of osteomyelitis but no radiographic findings of that disease, 111In alone is an appropriate nuclear medicine evaluation for ruling out infection if it is negative. However, if an area of 111In white blood cell uptake is present, a “simultaneous” 99mTc is often helpful in providing the anatomic correlation to differentiate osteomyelitis from infection that is limited to soft tissue.

Arthrodesis of the hindfoot and/or ankle is a commonly performed procedure for ankle or subtalar joint arthritis. Extensive arthrodesis for involvement of both the ankle and subtalar joints is performed more rarely, but is not uncommon. In all cases of hindfoot and ankle arthrodesis, positioning of the foot relative to the mechanical axis of the limb is extremely important. With proper alignment of the foot and appropriate shoe wear modifications, near normal gait can be

The use of PHOTOFRIN™ for photodynamic therapy of human gliomas has been studied by i.v. administration and laser photosensitization. Defining the uptake of PHOTOFRIN™ in the patient's tumor in comparison with the surrounding normal brain tissue is highly desirable for patient selection and study ofin vivo kinetics. We utilized a non-invasive approach to the detection of PHOTOFRIN™ uptake in brain tumors with111In-oxine radiolabeled PHOTOFRIN™ and external imaging and quantitation using a gamma camera. Biodistribution of111In-labeled PHOTOFRIN™ in 13 organs was determined in four dogs and 15 mice with gliomas.99mTc-DTPA was used as a control for nonspecific uptake. The greatest concentration of111In-PHOTOFRIN™ in the brain tumor occurred at 24 hours post i.v. administration. The brain tumor PHOTOFRIN™ uptake was seven times greater than that of normal brain. The decreased blood background at 72 hours made this the optimum time for imaging. Specific tumor tissue uptake of111In-PHOTOFRIN™ occurred, well beyond that resulting from blood-brain-barrier (BBB) breakdown.

The use of PHOTOFRIN(TM) for photodynamic therapy of human gliomas has been studied by i.v. administration and laser photosensitization. Defining the uptake of PHOTOFRIN(TM) in the patient's tumor in comparison with the surrounding normal brain tissue is highly desirable for patient selection and study of in vivo kinetics. We utilized a non-invasive approach to the detection of PHOTOFRIN(TM) uptake in brain tumors with In-111-oxine radiolabeled PHOTOFRIN(TM) and external imaging and quantitation using a gamma camera. Biodistribution of In-111-labeled PHOTOFRIN(TM) in 13 organs was determined in four dogs and 15 mice with gliomas. Tc-99m-DTPA was used as a control for nonspecific uptake. The greatest concentration of In-111-PHOTOFRIN(TM) in the brain tumor occurred at 24 hours post i.v. administration. The brain tumor PHOTOFRIN(TM) uptake was seven times greater than that of normal brain. The decreased blood background at 72 hours made this the optimum time for imaging. Specific tumor tissue uptake of In-111-PHOTOFRIN(TM) occurred, well beyond that resulting from blood-brain-barrier (BBB) breakdown.

The authors discuss a rare case in which bone metastases from a malignant glucagonoma mimicked avascular necrosis of the right femoral head initially on both bone scintigraphy and MRI. Repeated imaging 6 months later showed an additional L1 vertebral abnormality, indicating that the lesions were actually bone metastases. Retrospective analysis of the bone scan abnormality in the proximal femur revealed that the abnormal tracer uptake extended into the femoral neck, helping the radiologist to distinguish avascular necrosis from metastasis

Working together as co-investigators on the professional staff at the Medical College of Wisconsin, the authors of this article have had over five years of experience in the diagnostic use of monoclonal antibodies (MoAbs) for colorectal and ovarian cancer. We would like to share with you our approach to those MoAb imaging studies. While such agents have great potential for diagnosis and therapy, at the same time there can be problems and pitfalls. We present a practical and organized approach, which is the secret to success when undertaking MoAb imaging procedures. A complete review of MoAb technology and its application to nuclear medicine is beyond the scope of this article. However, a number of authoritative articles dealing with this topic have been published recently (1–12).

OBJECTIVE:The potential of MR imaging for evaluating myocardial perfusion and viability may make it the imaging procedure of choice for examining patients with ischemic heart disease. Accordingly, the purpose of this study is to determine the value of pharmacologically stressed, dynamically enhanced turbo-fast low-angle shot (FLASH) MR imaging in detecting chronic coronary artery disease.SUBJECTS AND METHODS:Five patients who had coronary angiography within the past 6-12 months were included in the study. After injection of 0.56 mg/kg of dipyridamole over 4 min, a bolus of 0.05 mg/kg of gadopentetate dimeglumine and subsequently 10 mCi (370 MBq) of 99mTc-sestamibi were injected. Short-axis turbo-FLASH images were obtained before injection and immediately, 1 min, 3 min, and 5 min after the injection of contrast material. Stress single-photon emission computed tomography (SPECT) images of the heart were obtained 60 min after the 99mTc-sestamibi injection. One and a half hours after an additional 30 mCi (1110 MBq) of 99mTc-sestamibi was injected, SPECT images were obtained with patients at rest. Prospective MR imaging evaluation of these five patients was performed by radiologists who did not know any of the imaging data. The MR imaging studies were compared with the near simultaneous 99mTc-sestamibi SPECT studies and with recent coronary angiograms.RESULTS:Thirteen myocardial segments were diagnosed as abnormal when 99mTc-sestamibi SPECT was used as the gold standard (12 reversible defects and one fixed defect). Twelve segments were normal on the 99mTc-sestamibi SPECT study. With SPECT as the gold standard, prospective MR imaging had a sensitivity of 77% and a specificity of 75%, whereas retrospectively it had a sensitivity of 92% and a specificity of 75%. With recent coronary angiography as the gold standard, prospective MR imaging had a sensitivity of 81% and a specificity of 100%. The quantitative data did not improve the accuracy of the qualitative analysis.CONCLUSION:Our results suggest that accurate prospective identification of chronic coronary artery disease may be possible with dynamically enhanced, pharmacologically stressed, turbo-FLASH MR imaging. Studies of additional patients to confirm this initial impression are warranted.