The role of Tc-99m (V) DMSA scintigraphy in the evaluation of superscan on bone scintigraphy

PURPOSE: This study evaluated the biodistribution of Tc-99m (V) DMSA in patients with superscans on bone imaging and defined its role in differentiating the underlying cause. METHODS: Nine patients (five with metastatic and four with metabolic bone disease) with classical superscans were entered into the study. All patients had the necessary radiologic and biochemical studies and a final diagnosis was reached accordingly. Tc-99m (V) DMSA scintigraphy was performed 1 week after Tc-99m MDP whole-body bone imaging. RESULTS: In four of five patients with widespread skeletal metastases, Tc-99m (V) DMSA scan showed diffusely increased bone uptake. In the remaining patient, the Tc-99m (V) DMSA scan showed a normal distribution pattern. All patients with metabolic bone disease had increased bone uptake on Tc-99m (V) DMSA scans. CONCLUSION: Tc-99m (V) DMSA shows increased bone uptake in patients having a superscan appearance in metastatic or metabolic bone disease. Tc-99m (V) DMSA imaging may play a role in the evaluation of patients with equivocal bone scan findings for a superscan.     

Tc-99m(V) DMSA imaging. A new approach to studying metastases from breast carcinoma.

Combined Tc-99m MDP skeletal imaging and Tc-99m(V) DMSA whole body scans to detect metastases were performed during the follow-up of 30 patients who underwent surgery for breast carcinoma. Eight patients had normal Tc-99m MDP and Tc-99m(V) DMSA scans and were declared free of metastatic disease, further confirmed by no change in symptomatology over a 1-year follow-up period. Twenty-two patients had positive Tc-99m MDP scans with varied skeletal involvement. Tc-99m(V) DMSA scans showed matched areas of increased radiotracer concentration in bony metastases in 20 of these patients. Tc-99m(V) DMSA concentration was not seen in traumatic vertebral collapse or in coexistent osteoarthritic disease in vertebral metastatic involvement. Interestingly, Tc-99m(V) DMSA showed increased concentration in brain and liver metastases. Pentavalent Tc-99m(V) DMSA appears useful for detecting skeletal and soft-tissue metastases in breast carcinoma, and can improve the specificity of Tc-99m MDP bone scans in screening for bone metastases.     

Pentavalent technetium-99m DMSA uptake in pseudofractures of osteomalacia

Tc-99m MDP and Tc-99m (V) DMSA images are described from a 49-year-old woman with chronic renal insufficiency complicated by osteomalacia. Clinical, biochemical, and radiologic bone profiles were compatible with osteomalacia. Osteomalacia is a condition associated with disorders in which mineralization of the organic matrix is defective. All bone lesions visualized with Tc-99m MDP also showed increased uptake of Tc-99m (V) DMSA. Tc-99m (V) DMSA accumulation has been reported in many malignant and some benign conditions. Pseudofractures in osteomalacia could be included in the spectrum of benign lesions that accumulate Tc-99m (V) DMSA.     

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.     

Visualization of uveal amelanotic melanoma with technetium-99m(V) dimercaptosuccinic acid

The possibility of using technetium-99m(V) dimercaptosuccinic acid, Tc-99m DMSA, in the evaluation of uveal amelanotic melanoma was assessed in this study. Both planar and SPECT images clearly demonstrated the tumor. Following confirmation of our results by contemporaneous ultrasonography and MRI the patient was treated with Iodine-125 brachytherapy. In combination with other diagnostic tests, Tc-99m(V) DMSA scintigraphy may play a role in the detection of uveal melanoma and its possible systemic metastases.     

Analogy between tumor uptake of technetium(V)-99m dimercaptosuccinic acid (DMSA) and technetium-99m-MDP

Sixty patients with a variety of malignant tumors were examined with Tc-99m(V) dimercaptosuccinic acid (DMSA) prepared by modification of a commercially available DMSA kit. Significant uptake of Tc-99m(V)-DMSA was observed in a number of tumors, offering additional clinically useful information. In the majority of cases in this study, however, the benefit of the Tc-99m(V)-DMSA image was limited because of low sensitivity. The most striking observation was the similarity between the tumor concentration of Tc-99m(V)-DMSA and the Tc-99m-MDP uptake in the tumor on the regular bone image. Therefore, patients with Tc-99m-MDP uptake in nonosseous tumor sites on the bone scan may be suitable candidates for tumor imaging with Tc-99m(V)-DMSA.     

Breast cancer imaging with PET and SPECT agents: an in vivo comparison

Several radiopharmaceuticals and imaging techniques are proposed for breast cancer imaging. Since limited data are available of the uptake of SPECT and PET radiopharmaceuticals in malignant breast tumors and their metastases the aim of this study was to compare the uptake values and to correlate these data with imaging findings. Methods: We have studied the uptake of F-18 FDG, Tc-99m MIBI and Tc-99m (V)DMSA in 31 tumors using immunosuppressed rats implanted with HH-16 clone 4 mammary tumor cells. Tumor gamma camera and PET imaging was performed to gain biokinetic data and uptake values by ROI-analysis. Results: Tumor uptake was highest for F-18 FDG > Tc-99m (V)DMSA > Tc-99m MIBI. The uptake ratios (tumor to muscle) correlated well with the ratios calculated by ROI-analysis determined by imaging. Conclusions: In this in-vivo model, F-18 FDG revealed the best uptake and imaging properties and may be the radiopharmaceutical of choice for routine breast cancer imaging.     

Visualization of orbital retinoblastoma with technetium-99m (V) dimercaptosuccinic acid

The potential contributions of technetium-99m (V) dimercaptosuccinic acid scintigraphy in the evaluation of orbital retinoblastoma, its local extensions and metastases were assessed in this study. Both planar and SPECT images clearly demonstrated the primary tumor and metastatic sites. Following confirmation of our results by contemporaneous ultrasonography, MRI and a subsequent incisional biopsy, the patient was treated with external beam radiotherapy and chemotherapy. This preliminary study showed that in combination with other diagnostic tests, Tc-99m (V) DMSA scintigraphy may play a role in the detection and follow-up of the local tumor extensions and metastases in patients with retinoblastoma.     

Pentavalent Tc-99m DMSA scintigraphy. Prospective evaluation of its role in the management of patients with medullary carcinoma of the thyroid.

Ten patients with suspected primary, recurrent or metastatic medullary carcinoma of the thyroid (MCT) were studied prospectively with Tc-99m(V) DMSA. Of these, two patients had primary disease, seven patients were asymptomatic but had persistent and serial elevations in serum calcitonin following previous thyroid resections for MCT, and one asymptomatic patient with normal serum calcitonin was studied because of suspected hilar nodes metastases. The serial calcitonin peak in the patients was 0.04-43ng/ml (normal less than 0.08ng/ml). Scintigraphy was considered positive in seven of the asymptomatic patients and equivocal in one. The two patients with primary disease had increased uptake before but not after thyroidectomy. Primary disease, localized recurrence and distant metastases in soft tissue (nine patients) and bone (one patient) were detected in these patients, and this resulted in early surgical resection (five patients) and radiotherapy (one patient). We conclude that Tc-99m(V) DMSA is a useful imaging agent in the evaluation of asymptomatic MCT patients with hypercalcitonemia.     

Using technetium-99m (V) dimercaptosuccinic acid to detect malignancies from single solid masses in the lungs

Fifty patients (43 male,7 female, age 31–77 years) with single solid masses in their lungs based on the findings of a chest X-radiograph [40 malignancies: 5 small cell carcinoma (Ca), 17 epidermoid Ca, 12 adeno Ca, 6 undifferentiated large cell Ca] and 10 benign lesions underwent technetium-99m (V) dimercaptosuccinic acid [^99m-(V)DMSA] scans to evaluate the usefulness of ^99mTc-(V)DMSA in the detection of lung Ca with different cell types and benign lesions. Only 43% (17/40) of the malignancies in the lungs were detected by ^99mTc-(V)DMSA, including 29% (5/17) epidermoid Ca, 50% (6/12) adeno Ca and 17% (1/6) undifferentiated large cell Ca of the lungs. However, all 5 cases of small cell Ca and 11 cases combined with bone metastasis were revealed by ^99mTc-(V)DMSA. In addition, 3 of the 10 benign lesions (2 organizing pneumonias, 1 benign tumor) presented with an uptake of ^99mTc-(V)DMSA. The diagnostic sensitivity, specificity and accuracy were 43%, 70% and 48%, respectively, in differentiating malignant from benign lesions for the single solid mass in the lungs. In conclusion, ^99mTc-(V)DMSA is of little or no use in the differentiation of lung Ca from single solid masses in the lungs. Correspondence to: C.H. Kao     

99Tc(m)(V)DMSA scintigraphy in skeletal metastases and superscans arising from various malignancies: diagnosis, treatment monitoring and therapeutic implications

Skeletal metastases arising from a wide variety of malignancies including a few cases with superscan appearance were evaluated using (99)Tc(m) MDP bone scanning and (99)Tc(m)(V)DMSA scintigraphy. Whole body planar scans were obtained at 3 h and 24 h after injection of 740 MBq (99)Tc(m) MDP and 5 days later at similar times after injection of 555 MBq of (99)Tc(m)(V)DMSA. A qualitative as well as quantitative comparison was made between the (99)Tc(m) MDP bone scan and the (99)Tc(m)(V)DMSA scan in detection of osseous metastases. The reference methods used for discordant or equivocal lesions were correlative morphological imaging modalities, for example additional conventional radiography, CT or MRI. The present pictorial review deals with the results of qualitative analysis of the study. A total of 75 cases have been evaluated. The vignettes illustrated in the present article demonstrate avid (99)Tc(m)(V)DMSA concentration in skeletal metastases from a wide variety of malignancies and thus expand the potential therapeutic indications for 188/186 Re(V)DMSA. The study also demonstrates the valuable supporting role a (99)Tc(m)(V)DMSA scan can play in the confirmation as well as evaluation of the extent of malignant infiltration in a suspected superscan in routine skeletal scintigraphy. In addition, a (99)Tc(m)(V)DMSA scan detected a number of metastatic lesions in and around joints and regions with previous surgical intervention that were inconclusive in the bone scan. The results in a few patients who were available for repeat scintigraphy following treatment, support the convincing evidence that (99)Tc(m)(V)DMSA accumulation may be a sensitive indicator of patient response to therapy. This might have an important bearing in the context of increasing "cold" bisphosphonate usage in the treatment of skeletal metastases, where skeletal scintigraphy with a radiolabelled bisphosphonate derivative can often be fallacious because of competitive inhibition by the non-labelled form.     

A comparison of the tumor-seeking agent Tc-99m(V) dimercaptosuccinic acid and the renal imaging agent Tc-99m dimercaptosuccinic acid in humans

Being aware of the ideal nuclear properties of Tc-99m, our interest has been focused on the design of the (+5) oxidation state Tc-99m(V) dimercaptosuccinic acid (Tc(V)-DMSA) as a tumor-seeking agent. Tc-99m(V) DMSA holds a TcO4(3-) core and, like PO4(3-), has excellent characteristics for tumor uptake, but has a different distribution than the well-known renal scanning agent, Tc-99m DMSA. The differences in chemical behavior of Tc-99m(V) DMSA and Tc-99m DMSA are discussed. Three cases in which neoplasms were studies with Tc-99m(V) DMSA and Tc-99m DMSA are presented. Tc-99m DMSA and Tc-99m(V) DMSA, having a common ligand and tracer but, with the metal ion core in a different oxidation state, the uptake characteristics are altered markedly.     

Scintimammographic findings of in situ ductal breast carcinoma in a double-phase study with Tc-99m(V) DMSA and Tc-99m MIBI value of Tc-99m(V) DMSA

The authors present a case of in situ ductal carcinoma of the breast (DCIS) with no associated mass in a 46-year-old woman examined with Tc-99m MIBI and Tc-99m(V) DMSA scans, which were acquired in separate sessions 10 minutes and 60 minutes after injection. Histologic analysis revealed a small (<1 cm) infiltrating ductal carcinoma located within the DCIS. Mammography showed a cluster of microcalcifications on a very dense parenchymal background. Tc-99m(V) DMSA was characterized as positive for DCIS, especially in the delayed image. Tc-99m MIBI failed to identify the lesions previously noted. In conclusion, Tc-99m(V) DMSA scintimammography seems to have an advantage and could improve the detection of nonpalpable in situ breast carcinomas.     

Biodistribution on Tc-99m labeled somatostatin receptor-binding peptide (Depreotide,NeoTec) planar and SPECT studies

PURPOSE: To determine the biodistribution of Tc-99m labeled somatostatin receptor-binding peptide (Depreotide) on planar and SPECT studies of the thorax and upper abdomen in order to improve diagnostic accuracy. METHODS AND MATERIALS: Retrospectively 29 planar and SPECT studies from 28 patients (all males, average age of 65.79) were reviewed. All the patients had been referred for evaluation of solitary pulmonary nodules. Two to four hours after IV injection of 555- to 740-MBq (15-20 mCi) Tc-99m Depreotide, anterior and posterior total body images, and anterior, posterior, right lateral and left lateral planar images were obtained, and thoracic SPECT was acquired with a three-head gamma camera. The degree of uptake in the lungs, thoracic cage, and organs of the upper abdomen was rated from "0" to "++++". RESULTS: The range of normal activity in the thorax includes cardiac, "0"; pulmonary, "+"; rib, "+/++"; sternum, "++"; vertebrae, "++". The degree of normal activity seen in the upper abdominal organs includes liver and spleen, "+++", and kidneys, "+++/++++". Eight patients with emphysema had diffuse pulmonary uptake graded as "+/++". One patient with left pneumonectomy and radiation therapy to the left hemithorax had photon-deficiency in the left hemithorax and decreased to absent uptake including the vertebrae and ribs. Although some cases had background pulmonary uptake of Tc-99m Depreotide, the bone/ bone marrow activity of the thoracic cage including the ribs, sternum, and thoracic spine is sufficiently great enough to produce a clear distinction between bone and lung in the thoracic cavity that gives high-contrast resolution on SPECT. CONCLUSIONS: The intensity of radioactivity in the sub-diaphragmatic organs such as the liver, spleen, and kidneys provides useful guidance for the categorization of pulmonary lesions. The uptake of land marks such as the sternum, which is anteriorly located, and the thoracic vertebrae, which are posteriorly located in the thoracic cage, can be used in the localization of a Depreotide avid tumor.     

The value of radionuclide studies in children with autosomal recessive polycystic kidney disease

PURPOSE: To describe and analyze the appearances of autosomal recessive polycystic kidney disease (ARPKD) on Tc-99m DMSA and Tc-99m HIDA scintigraphy. MATERIALS AND METHODS: The authors evaluated scintigraphic findings for 13 boys and 9 girls (age range, 2 months to 22.75 years; mean, 7.5 years) with ARPKD. Fourteen children underwent Tc-99m DMSA and 20 underwent Tc-99m HIDA scintigraphy according to European guidelines. Kidney outline, internal structure, tracer uptake, and differential function were analyzed on Tc-99m DMSA images, whereas relative liver lobe sizes, hepatocyte tracer uptake, time to peak, and excretion into the biliary tree and gut were evaluated on Tc-99m HIDA scans. RESULTS: On Tc-99m DMSA images, loss of kidney outline and internal structure was seen in 75% of the scans, and patchy tracer uptake with focal defects throughout the kidneys, particularly at the poles, was evident in 93%. In 85% of the cases, the Tc-99m DMSA changes did not correlate with the ultrasonographic findings where the kidneys are uniformly affected. Characteristic findings on Tc-99m HIDA scans were enlarged left liver lobe in 80%, a delay in maximal hepatocyte uptake in 68%, delayed tracer excretion into the biliary tree in 32% (with stasis in the prominent intrahepatic biliary ducts in 50% or pooling into the segmentally dilated biliary ducts in 25%), and delayed excretion into the gut in 40% of patients. CONCLUSIONS: In a child with clinically enlarged kidneys that appear diffusely hyperechoic on ultrasound, the appearances on Tc-99m DMSA imaging strongly support the diagnosis of ARPKD. The Tc-99m HIDA findings, especially of an enlarged left lobe of the liver with bile stasis or dilatation, further support the diagnosis.     

Diffuse thoracoabdominal radioactivity seen in bone imaging

Diffusely increased radioactivity in the thoracoabdominal region (lower thorax and/or upper abdomen) occasionally has been observed when performing Tc-99m phosphonate bone studies. To assess the significance of activity in this finding, 1100 bone scintigrams were reviewed and the clinical data and other diagnostic imaging procedures were evaluated in these cases. With the exclusion of Tc-99m sulfur colloid liver-spleen scans 18 patients were found to have mild but diffuse increased radioactivity in the thoracoabdominal region either on the right or left. Clinical findings in these cases with abnormal uptakes were pleural effusions (six cases), hepatic colonic metastases (six cases), splenic metastases from bronchogenic carcinoma (one case), abdominal and peritoneal colonic metastases (one case), a massive metastatic squamous cell carcinoma (from lung) in the right lower chest (one case), and defective radiopharmaceuticals (three cases). Since the defective radiopharmaceuticals contained 5% of hydrolyzed reduced Tc-99m colloid by thin-layer chromatography, each of three patients received approximately 740 mu Ci of Tc-99m sulfur colloid. Factors to be considered in the interpretation of diffuse thoraco-abdominal activity from a bone agent should include splenic or hepatic metastases, a Tc-99m sulfur colloid splenic or hepatic metastases, a Tc-99m sulfur colloid study within the previous 24 hours, pleural effusion, faulty radiopharmaceuticals, and abdominal and peritoneal colonic metastases.     

99mTc(V)DMSA quantitatively predicts 188Re(V)DMSA distribution in patients with prostate cancer metastatic to bone

Rhenium-188 dimercaptosuccinic acid complex [188Re(V)DMSA], a potential therapeutic analogue of the tumour imaging agent 99mTc(V)DMSA, is selectively taken up in bone metastases in patients with prostate cancer. It would be helpful in planning palliative radionuclide therapy if 99mTc(V)DMSA could be used to predict tumour and kidney retention of 188Re(V)DMSA. The aim of this study was to determine the correlation between tumour-to-normal tissue ratios and kidney-to-soft tissue ratios of 99mTc(V)DMSA and 188Re(V)DMSA. This would determine whether a scan with 99mTc(V) DMSA could be used to identify patients for whom 188Re(V)DMSA treatment would be contra-indicated, and enable prediction of relative kidney and tumour radiation absorbed dose in 188Re(V)DMSA treatment. Ten patients with prostate carcinoma were recruited following observation of disseminated bone metastases on a recent 99mTc-hydroxydiphosphonate bone scan. Whole-body planar scans were obtained at ca. 4 h and 24 h after hydration and injection of 600 MBq 99mTc(V)DMSA, and a week later, at similar times after hydration and injection of 370 MBq 188Re(V)DMSA. A triple-energy window (TEW) scatter correction was applied to the 188Re scans. Counts per pixel were determined in regions of interest drawn over metastatic sites, kidneys and normal soft tissue. Tumour-to-soft tissue ratios were significantly lower (by a factor of approximately 0.8 after the TEW was applied) on 188Re scans than on 99mTc scans, but the two were highly linearly correlated both in all individual patients and in tumours pooled from all patients together both at 4 h and at 24 h. Kidney-to-soft tissue ratios were similarly correlated and were lower for 188Re than for 99mTc by a similar factor. Both tumour- and kidney-to-soft tissue ratios increased between 4 and 24 h but the latter increased more. In conclusion, only minor differences were seen between 99mTc and 188Re scans, and kidney-to-background ratios on 188Re scans were not higher than on 99mTc scans. These differences are insufficient to infer that they are due to a real difference in biodistribution, and they may be due only to different physical imaging characteristics. Thus 99mTc(V)DMSA scans are predictive of 188Re(V)DMSA biodistribution and could be used to estimate tumour and renal dosimetry and assess suitability of patients for 188Re(V)DMSA treatment.     

Skull base involvement by a nasopharyngeal carcinoma shown by Tc-99m MDP SPECT but not by computed tomography

PURPOSE: Plain radiographs, computed tomography (CT), and more recently magnetic resonance imaging (MRI) are used routinely to stage carcinoma of the nasopharynx. Tc-99m methylene diphosphonate (MDP) SPECT is seldom used for local staging of the disease. MATERIALS AND METHODS: Plain radiographs and CT were used to stage squamous carcinoma of the nasopharynx in a 50-year-old man with a left XII nerve palsy. RESULTS: Findings of the plain radiographs were normal, whereas the CT scan revealed a nonhomogenous hyperdense mass in the nasopharynx but intact underlying bone. Given the symptoms, a Tc-99m MDP planar scan was ordered and showed no enhanced uptake, but SPECT images obtained at the same time revealed markedly increased focal radiotracer uptake in the region of the tumor, indicating osseous involvement. CONCLUSION: Possible bony invasion with a nasopharyngeal carcinoma may be better shown with MDP SPECT than with planar isotope bone scans, plain radiographs, or CT.     

Imaging of head and neck tumors with technetium(V)-99m DMSA. A new tumor-seeking agent

Tumor scintigraphy, using Tc(V)-99m DMSA was performed on 76 patients with head and neck tumors. In 32 cases, SPECT also was performed. Tc(V)-99m DMSA was found to have a sensitivity of 75% (56 cases), a specificity of 85% (20 cases) and an accuracy of 78% on planar imaging. ECT studies showed accumulation of Tc(V)-99m DMSA in all 25 malignant cases studied. However, in benign tumors, four of seven cases (57%) showed radionuclide uptake. Tc(V)-99m DMSA has superior physical properties to Ga-67 and could be of use in the diagnosis of head and neck tumors.     

Increased bone marrow uptake on Tc-99m DMSA scintigraphy in a patient with renal osteodystrophy

A 16-year-old male patient was evaluated with Tc-99m Diethylenetriamine-pentaacetic acid (DTPA) and Tc-99m 2–3 Dimercaptosuccinic acid (DMSA) scintigraphy for renal failure secondary to renal calculi. The uptake in the renal cortex was significantly decreased both on DMSA and DTPA studies. Uptake calculation on DMSA scintigraphy in the kidneys disclosed values of less than 5 %. The activity in the liver and bone was significantly increased. A bone scan performed with Tc-99m methylene diphosphonate (MDP) revealed increased bone uptake with decreased soft tissue activity. Findings on bone scan were compatible with super scan, most likely due to renal osteodystrophy. This case illustrates the altered biodistribution of Tc-99m DMSA and a shift of the radiopharmaceutical to the bone marrow which is mot likely related to colloid formation due to changes in mineral balance in patients with renal failure.