Lesion Detectability and Clinical Effectiveness of Dual-head Coincidence Gamma Camera Imaging in Comparison with Dedicated PET Systems in Tumour Patients

The lesion detection capability and clinical effectiveness of dual-head coincidence gamma camera imaging (c-PET) were compared with those of dedicated positron emission tomography (d-PET) in 37 cancer patients who underwent whole-body c-PET and d-PET imaging after administration of 370 − 540 MBq 18F-fluorodeoxyglucose. Eighty-nine lesions were detected on c-PET whereas 133 lesions were seen with d-PET imaging. The relative sensitivity of c-PET compared with d-PET was 62% and 73% for lesions < 15 and ≤ 15 mm, respectively, and the relative concordance rate was 84% when the patients were restaged. Since the lesion detection rate of c-PET imaging was lower than that of d-PET, the detection of small lesions, therefore, requires care. The clinical effectiveness of c-PET, however, was similar to that of d-PET and, therefore, it is concluded that c-PET can be used as an alternative to d-PET, particularly considering the high cost and limited availability of d-PET cameras.

The capacity of some newly bacteria and fungi for biodegradation of herbicide trifluralin under agiated culture media

Bioremediation is the use of microorganisms to degrade environmental contaminants (pesticides, polyaromatic hydrocarbons etc.) into less toxic forms or compounds. In this study microbial biodegradation of trifluralin was performed in liquid media with 11 different types of identified fungi and bacteria cultures and their mixtures in agiated culture media. The isolated fungi and bacteria mixtures showed the highest degradation, reaching 93% in the chemical oxygen demand (COD) parameter in four days and 82% as trifluralin active ingredient in five days. Bacteria and fungi mixtures achieved 69% and 66% degradations of trifluralin active ingredient respectively. In the fungi studies, the best removal was achieved by M.Chlamydosporia at 80%, in the bacteria studies, the best removal was achieved by Bacillus simplex about 95% in five days. These different removal rates were due to the microbial differencies.

Nitrogen removal during secondary treatment by aquatic systems

Within the context of this study, two lab-scale aquatic plant reactors consisting of duckweed (Lemna minor) ponds, were investigated for the removal of nitrogen forms during the secondary treatment of domestic wastewater. TKN, NH3-N and NO3-N parameters have been measured in both reactors for hydraulic retention times ranging from 3.3 days to 23 days and at various distances from the inlet of reactors. The results were evaluated for hydraulic retention times, hydraulic loading rates and mass loading rates. I was concluded that hydraulic and mass loading parameters were more meaningful than hydraulic retention time. Optimum nitrogen removal values of hydraulic loading rate and mass loading rate were found to be 1.2 cm/day and 90-160 mg TKN/m2-day, respectively. At the higher and lower loading rates, nitrogen removal efficiency was lower than those at optimum conditions. Effluent TKN concentration was around 2.5 to 3.0 mg/l while NH3-N concentration was almost zero at these loading conditions. On the other hand, effluent NO3-N concentrations changed between 7 mg/l to 11 mg/l. When investigating the longitudinal profile, values were reduced rapidly along the reactors. It was concluded that most of the nitrogen conversion occurred at the beginning of the reactor.

Post-surgical ablation of thyroid remnants with high-dose (131)I in patients with differentiated thyroid carcinoma

The aims of this study were to evaluate the efficacy of an empirically determined "fixed" high ablative dose of radioiodine ((131)I) therapy and to determine the utility of ultrasonography (US) in dose determination. A retrospective analysis was performed of 242 thyroid cancer cases treated with "fixed" high-dose (131)I for ablation of thyroid remnants without a pre-ablative (131)I diagnostic scintigraphy or radioiodine uptake study. Treatment doses ranged from 1850 MBq (50 mCi) to 7.4 GBq (200 mCi). The selection of the treatment dose was based on the surgical and pathological findings as well as the remnant thyroid volume calculated by US. A successful ablation was defined as the absence of activity in the thyroid bed on subsequent imaging studies. Successful ablation was obtained in 218 of the 242 patients (90%). In 162 of the 218 patients (74.3%), successful ablation was achieved after a single (131)I treatment. The remnant thyroid volume calculated by US was significantly different (P=0.04) between those who were successfully ablated and those who were not. The total (131)I dose needed for successful ablation was significantly higher in males (P=0.003). Patients with higher post-operative thyroglobulin (Tgb) levels and patients with a higher stage of disease required higher doses (P=0.036 and P=0.021 respectively). Serum Tgb levels were under 10 ng.ml(-1) in 220 of the 242 patients (90%) following radioiodine ablation while not receiving L-thyroxine suppression. Nineteen patients (7.8%) showed metastases on post-therapy scan and successful treatment was achieved in 11 of 19 (57.8%). Four of the 19 patients with distant metastases (revealed on post-treatment scan) were found to have been given a treatment dose of less than 200 mCi based on the proposed empirical approach. These results indicate that "fixed" high-dose (131)I treatment is clinically feasible with an acceptable dose underestimation rate, and the utilization of US in the determination of the thyroid remnant volume provides more accurate and reproducible results.

Utility of ventilation and perfusion scan in the diagnosis of young military recruits with an incidental finding of hyperlucent lung

Swyer-James-MacLeod syndrome (SJMS) is considered to be a relatively uncommon disease presenting with unilateral hyperlucent lung due to hypoplasia of a pulmonary artery and bronchiectasis of the affected lung. In this report, we describe the ventilation-perfusion (V/Q) scan findings of nine male recruits (aged 20-29 years, mean 24.4+/-2.96 years) with SJMS in whom the diagnosis was first established in adulthood. V/Q scan findings of all patients were compared with those on planar radiographs, pulmonary function studies, high resolution computed tomography (HRCT) and digital subtraction angiography (DSA). The ventilation (133Xe) and perfusion (99Tcm-macro-aggregated albumin) scans showed the characteristic pattern of a matched V/Q defect and marked air trapping on the washout phase on 133Xe scintigraphy. HRCT displayed hypodense lung with integrity of main airways, and markedly diminished vasculature on the affected side in all patients. A smaller pulmonary artery on the affected side with poor peripheral vasculature was observed with DSA in all patients. All patients had features of obstructive airway disease in varying degrees on pulmonary function studies. In contrast to other imaging methods, bronchiectasis as an etiological factor was displayed on HRCT. Some pulmonary areas, which were normal on HRCT and planar radiographs, showed air trapping on V/Q scan. Although a V/Q scan was more helpful in determining the extent of the disease and correlates well with conventional imaging methods, HRCT was the most valuable imaging method for the evaluation of aetiology in unilateral hyperlucent lung.

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.

The comparison of dual phase Tc-99m MIBI and tc-99m MDP scintimammography in the evaluation of breast masses: preliminary report

The aim of this prospective study was to determine the diagnostic value of Tc-99m MDP scintimammography (SMG) for the detection of breast cancer in patients with breast masses and to compare the results with Tc-99m MIBI scintimammography. Twenty patients, categorized as suspicious, positive or benign for breast cancer according to the mammographic findings were included in the study. Dual phase Tc-99m MIBI and Tc-99m MDP SMG were performed in the prone lateral position within 5 days of each other. Although early and late Tc-99m MIBI SMG showed equal (90.4%) sensitivity, the specificity of late Tc-99m MIBI (87.5%) was found superior to early (62.5%) imaging. The overall sensitivity and specificity of early Tc-99m MDP SMG were 71.4% and 62.5%, respectively. Although late Tc-99m MDP imaging showed 100% specificity, its sensitivity was only 23.8%. In the patients with palpable masses, both early Tc-99m MDP and Tc-99m MIBI showed equal sensitivity (100%), but the sensitivity of early Tc-99m MIBI (37.5%) was found slightly higher than Tc-99m MDP (25.0%) for nonpalpable breast lesions. The sensitivity of Tc-99m MIBI and Tc-99m MDP SMG in detecting metastatic axillary involvement was 66.6% and 50%, respectively. High sensitivity and specificity together with its low cost, easy availability and the possibility of detecting bone metastases seems to make Tc-99m MDP a contributive agent in the evaluation of breast lesions as an alternative to Tc-99m MIBI.

The effect of trimebutine maleate on gastric emptying in patients with non-ulcer dyspepsia

The study was designed to investigate the effect of trimebutine maleate, a drug used in both hyperkinetic and hypokinetic motility disorders, on gastric emptying in patients with non-ulcer dyspepsia having prolonged gastric emptying rates and to compare the parameters used for the determination of the lag period observed during the emptying of solid foods from the stomach. Gastric emptying was measured by the radionuclide technique. Twenty normal volunteers and 43 patients with non-ulcer dyspepsia participated in the study. Radionuclide imaging was performed by using a solid meal labeled with 99mTc-tin colloid. Of the patients with non-ulcer dyspepsia, 20 had prolonged gastric emptying. They were given three weeks of oral treatment with trimebutine maleate and had their radionuclide gastric emptying study repeated. Treatment with trimebutine maleate resulted in reduction in duration of the lag period and less retention of food at 100 minutes (p < 0.0005). After treatment with trimebutine maleate, no significant difference has been observed in the mean symptom score of patients with prolonged gastric emptying. Among the parameters used for the determination of the lag period, lag period determined by a mathematical equation (TLAG) has been found to be longer than the lag period determined by visual inspection of the images (VLAG) and there was correlation between the two parameters when the lag time was short.

Comparison of Tc-99m EC and Tc-99m DTPA captopril scintigraphy to diagnose renal artery stenosis

PURPOSE

Although, captopril scintigraphy is a well established method to detect renovascular hypertension, the optimal radiopharmaceutical for this test remains to be determined. Recently, Tc-99m ethylenedicysteine (Tc-99m EC) appeared as an alternative agent for captopril scintigraphy. The aim of this study was to compare the diagnostic accuracy of Tc-99m EC with Tc-99m DTPA, which is a well-established renal radiopharmaceutical for the captopril test.

METHODS

Nineteen hypertensive patients who had various degrees of renal artery stenosis on angiography were included in the study. All patients had baseline and captopril Tc-99m EC and Tc-99m DTPA scintigraphy within a 1-week period. The results were compared with angiography and in eight patients with changes in blood pressure after revascularization. The images were interpreted without knowledge of the angiography and revascularization data as low, intermediate, or high probability for hemodynamically significant renal artery stenosis, which was defined as an area of stenosis exceeding 50%.

RESULTS

Tc-99m EC and Tc-99m DTPA study results were in agreement in 16 of the 19 patients. In two patients with branch artery stenosis, Tc-99m EC was definitely superior to Tc-99m DTPA and correctly identified the probability of stenosis on scintigraphy. On kidney analysis, Tc-99m EC had a slightly greater diagnostic sensitivity compared with Tc-99m DTPA (79% vs. 68%; P > 0.05 by the chi-squared test) but equal specificity (93% for both agents). Both Tc-99m EC and Tc-99m DTPA showed the same accuracy in predicting the outcome after revascularization in all but one patient with branch artery stenosis, in whom Tc-99m EC accurately predicted a successful outcome of the intervention but Tc-99m DTPA did not. Tc-99m EC had better renal uptake in patients with decreased renal function and provided more dramatic evidence of renogram changes after captopril intervention, which resulted in more confident interpretation.

CONCLUSIONS

There is no significant difference between Tc-99m EC and Tc-99m DTPA captopril scintigraphy for detecting renal artery stenosis. However, because of the better imaging characteristics and more confident interpretation provided by the dramatic changes in the degree of renogram abnormality after captopril intervention, Tc-99m EC captopril scintigraphy should be used, particularly in patients with decreased renal function or branch artery stenosis.

99Tcm-MIBI scintimammography in the evaluation of breast lesions and axillary involvement: a comparison with mammography and histopathological diagnosis

The aim of this prospective study was to determine the diagnostic value of prone lateral 99Tcm-MIBI scintimammography in the detection of primary breast cancer and axillary lymph node involvement in patients with breast lesions. We evaluated 83 palpable and 22 non-palpable lesions in 77 consecutive patients with a clinically palpable mass and/or suspicious mammographic finding. Early and late scintimammograms were performed after the intravenous injection of 740 MBq 99Tcm-MIBI. The overall sensitivity of both scintimammography and mammography in the detection of primary breast cancer was 94%. The overall specificity was 84% and 56% for scintimammography and mammography respectively. In the patients with palpable masses, the sensitivity of scintimammography was 97% and the specificity was 84%; in those with non-palpable masses, the sensitivity was 35% and the specificity 100%. For the detection of axillary lymph node involvement, the sensitivity and specificity of scintimammography were 68% and 93% respectively. However, conventional mammography showed 37% sensitivity and 86% specificity. In conclusion, scintimammography is an accurate and clinically valuable tool for evaluating palpable and non-palpable breast abnormalities. In addition to its high sensitivity, it improves the specificity of mammography both in the evaluation of breast masses and in the detection of axillary involvement.

99mTc-ethylenedicysteine-folate: a new tumor imaging agent. Synthesis, labeling and evaluation in animals

It is known that membrane folic acid receptors are responsible for cellular accumulation of folate and folate analogs such as methotrexate and overexpressed on various tumor cells. However, these receptors are highly restricted in normal differentiated tissues. Results of limited in vitro and in vivo animal studies suggest that folate receptors could be a potential target for tumor imaging. This study aimed to develop a 99mTc-labeled folic acid using ethylenedicysteine (EC) as a chelator and evaluate its labeling efficiency and potential use as a tumor seeking agent. Tissue distribution of 99mTc-EC-folate was determined in breast tumor-bearing rats at 20 min, 1, 2, and 4 h (n = 3/time interval, 370 KBq/rat, i.v.). Blocking study was employed to determine receptor-mediated process; 99mTc-EC-folate was co-administrated with 50 and 150 mumol/kg of cold folic acid to tumor-bearing rats. Planar imaging and whole-body autoradiograms were performed. The data was compared to that using 99mTc-EC (control). In animal studies, tumor/blood count density ratios at 20 min-4 h increased from 0.81 +/- 0.09 to 1.23 +/- 0.13 with 99mTc-EC-folate. Conversely, these values showed time-dependent decrease from 0.77 +/- 0.32 to 0.65 +/- 0.01 with 99mTc-EC in the same time period. Tumor/muscle and tumor/blood count density ratios significantly decreased with folic acid co-administrations. Planar images and autoradiograms confirmed that the tumors could be visualized clearly with 99mTc-EC-folate.

Discordance of sialography and scintigraphy in unilateral chronic sialadenitis

A Tc-99m pertechnetate salivary gland scintigraphy, digital subtraction sialography (DSS) and cytological findings of a 48-year-old female who received I-131 therapy for the treatment of follicular carcinoma of thyroid are presented. Post radioiodine therapy sialoscintigraphy showed increased blood flow and uptake with decreased secretion in the left parotid gland suggesting acute inflammation. In contrast, DSS and fine needle aspiration biopsy (FNAB) findings were consistent with chronic sialoadenitis. Follow-up scintigraphy one month later showed normal blood flow and decreased uptake and confirmed the diagnosis of chronic sialoadenitis. In right of this case, we conclude that since management of sialoadenitis depends on the stage of inflammation scintigraphic findings should be interpreted together with radiology and FNAB findings if necessary. When chronic sialoadenitis is followed by acute exacerbations, diagnosis based exclusively on sialoscintigraphic findings may result in inadequate patient management.

Evaluation of hepatocyte function after extracorporeal shock wave lithotripsy with hepatobiliary scintigraphy

OBJECTIVE

Extra corporeal shock wave lithotripsy is a promising and effective therapy mode in the nonsurgical therapy of gallstones. This prospective study was conducted to investigate the effects of ESWL on hepatocellular function, using quantitative hepatobiliary scintigraphy, serum aminotransferase, alkaline phosphatase (ALP), amylase (AML), and direct and indirect bilirubin levels.

METHODS

The study consisted of 22 patients with ultrasonographically documented gallstones. Hepatobiliary scintigraphy was applied to all patients before ESWL and biochemical tests were performed. Scintigraphy and biochemical tests were repeated in 16 patients 24 h, in seven patients 72 h, and in six patients 1 wk after ESWL. The hepatic extraction fraction (HEF) was calculated using deconvolution analysis of scintigraphic data.

RESULTS

All patients' pre-ESWL biochemical tests and HEF values were within the normal range. The 24- and 72-h post-ESWL aminotransferase, ALP, and AML levels and HEF values were significantly different from pre-ESWL values (p < 0.05). After 1 wk this difference disappeared. Decreased HEF values were observed in 50% of patients 24 h, in 71.7% of patients 72 h, and in 16.6% of patients 1 wk after ESWL. A direct relationship was also observed between the number of shocks applied and the degree of impairment in HEF values.

CONCLUSION

Transient hepatocellular dysfunction, which usually occurs after ESWL, can be demonstrated and monitored using quantitative hepatobiliary scintigraphy.

Discordance of Sialography and Scintigraphy in Unilateral Chronic Sialadenitis

A Tc-99m pertechnetate salivary gland scintigraphy, digital subtraction sialography (DSS) and cytological findings of a 48-year-old female who received 1-131 therapy for the treatment of follicular carcinoma of thyroid are presented. Post radioiodine therapy sialoscintigraphy showed increased blood flow and uptake with decreased secretion in the left parotid gland suggesting acute inflammation. In contrast, DSS and fine needle aspiration biopsy (FNAB) findings were consistent with chronic sialoadenitis. Follow-up scintigraphy one month later showed normal blood flow and decreased uptake and confirmed the diagnosis of chronic sialoadenitis. In light of this case, we conclude that since management of sialoadenitis depends on the stage of inflammation scintigraphic findings should be interpreted together with radiology and FNAB findings if necessary. When chronic sialoadenitis is followed by acute exacerbations, diagnosis based exclusively on sialoscintigraphic findings may result in inadequate patient management.

A case of thyrotropin-secreting pituitary microadenoma with normal thyrotropin alpha-subunit level

We present a 32-year-old male with a thyrotropin (TSH)-secreting pituitary microadenoma with normal alpha-subunit (SU) and/or alpha-SU/TSH molar ratio. An interesting feature of this patient is that the size of the pituitary tumor remained unchanged during a 6-year follow-up without treatment. The tumor was clearly visualized with somatostatin receptor imaging, indicating that it was somatostatin receptor-positive. Subcutaneous injection of 100 microg octreotide acetate three times daily resulted in significant reduction of TSH and free thyroid hormones 6 weeks after initiation of treatment. However, tumor size was not changed 3 months after initiation of octreotide therapy and thyroid hormones, but not TSH level, eventually increased in spite of increasing the octreotide dosage up to 600 microg/day. This led to discontinuation of treatment. The patient responded only temporarily to octreotide in spite of somatostatin receptors. This case further demonstrates that a normal alpha-SU and/or alpha-SU/TSH molar ratio cannot exclude the possibility of a TSH-secreting pituitary adenoma.

Comparison of 99mTc(V)-DMSA, 201Tl and 99mTc-MIBI imaging in the follow-up of patients with medullary carcinoma of the thyroid

Radionuclide scanning with tumour-seeking agents such as pentavalent technetium-99m dimercaptosuccinic acid [99mTc(V)-DMSA], thallium-201 and technetium-99m sestamibi (MIBI) has been reported to be useful in the detection of medullary thyroid carcinoma (MTC). We undertook a study in 14 MTC patients to determine the comparative imaging potential of 201Tl, MIBI and 99mTc(V)-DMSA in the detection of recurrent or metastatic MTC. All patients underwent total thyroidectomy and had persistently elevated serum calcitonin levels after the surgery. Scintigraphic studies were carried out 20 min after the injection of 111 MBq of 201Tl or 555 MBq of MIBI and 2 h following the injection of 370 MBq of 99mTc(V)-DMSA. All scintigraphic findings were correlated with contemporaneous CT or MRI studies. CT, MRI and bone scans showed 42 (26 bone, 16 soft tissue) metastatic sites in 11 of the 14 patients. In the remaining three patients no lesions were detected during diagnostic evaluation. 99mTc(V)-DMSA showed all of the soft tissue metastases but could not show two bone lesions. On the other hand, MIBI imaging was false-negative in 22 (52%) sites and 201Tl was false-negative in 34 (80%) sites. Overall, lesion detection sensitivities for 99mTc(V)-DMSA, MIBI and 201Tl were 95%, 47% and 19% respectively. We conclude that 99mTc(V)-DMSA is clearly superior to MIBI and 201Tl in the follow-up of MTC patients.

Sequential changes in serum thyroid peroxidase following radioiodine therapy of patients with differentiated thyroid carcinoma

To determine the detectability and the time course of serum thyroid peroxidase (TPO) levels before and 1, 2, 4, and 6 months after 131I administration, we evaluated TPO in 13 selected patients with differentiated thyroid carcinoma (DTC) whose sera did not contain antimicrosomal or antithyroglobulin (Tg) antibodies. All patients received 131I therapy 6 or 8 weeks after thyroid surgery for ablation of the postsurgical thyroid remnant. Serum samples were also collected from 10 normal subjects. Measurement of TPO was carried out by using a new commercially available immunoluminometric assay with a sensitivity of 30 pg/mL. Serum Tg was measured by RIA with a sensitivity of 2.6 micrograms/L before and 6 months after 131I administration. In all patients, a standard total body scan was obtained before and 6 months after 131I administration. TPO was undetectable in all sera from normal subjects. However, serum TPO became detectable in all patients with DTC during the study, whereas rescans were either negative or positive and appeared not to be related to the radioiodine dose given, histology of the thyroid tumor, residual thyroid volume, TSH levels, or age of patients. However, a significant negative correlation was present between TPO levels before 131I administration and the time from surgery (r = -0.82, P < 0.001). Six of 13 patients had increased TPO levels 1 month after 131I administration. Serum TPO levels tended to decrease during follow-up in most patients (7 of 10) with a negative rescan. In 3 patients with positive rescans, TPO levels tended to increase during follow-up. Patients with negative rescans had values of serum TPO overlapping the range of values seen in patients with positive rescans, thus demonstrating the inability of TPO assay as a useful marker for following patients with DTC. We found no correlation between Tg and TPO levels measured before and 6 months after 131I administration, thereby excluding TPO levels as a marker for thyroid cancer. Our results suggest that TPO, unlike Tg, does not appear to be a useful marker for following patients with DTC.

The visualization of pulmonary tuberculosis with Tc-99m (V) DMSA and Tc-99m citrate in comparison to Ga-67 citrate

Two patients with active tuberculosis confirmed by chest radiography and positive sputum smears were included in this study to determine whether a Tc-99m labeled agent, such as DMSA or citrate could localize such lesions in comparison to Ga-67 citrate. Both patients had Tc-99m (V) DMSA, Tc-99m citrate, and Ga-67 citrate scanning at 1-day to 5-day intervals. Both patients had positive scan findings with all three radiopharmaceuticals. However, the quality of Tc-99m (V) DMSA scans was superior to Tc-99m citrate, which showed faint uptake. Tc-99m (V) DMSA may be a better alternative to Ga-67 citrate in the assessment of the activity and extent of tuberculosis.

Better visualization of retinoblastoma metastases with Tc-99m sestamibi versus Tl-201

Tc-99m sestamibi has been shown to accumulate in several primary malignant tumors, but data regarding its use in the detection of distant metastases are limited. Despite its physical limitations, Tl-201 now has a definite place in the routine evaluation of certain primary and metastatic tumors. This report describes the value of Tc-99m sestamibi and its superiority to Tl-201 in the visualization of distant metastases in a 2-year-old girl with bilateral retinoblastoma. Three sites of soft tissue and bone metastasis were demonstrated by Tc-99m sestamibi imaging. Of these metastases, the one in the parieto-occipital region showed evident Tl-201 uptake, while the other two in the right arm and chest wall showed only slightly increased uptake, which could hardly be spotted without the confirmation of a later Tc-99m sestamibi scan. The scintigraphic findings were confirmed with histopathologic examination. Tc-99m sestamibi scan is effective and superior to Tl-201 in the detection of distant soft tissue and bone metastases from retinoblastoma.

Radiologic evaluation of urinary tract infection

This prospective study was designed to investigate the most relevant radiological approach for the evaluation of urinary tract infections (UTI) in childhood. In the first 48 hours following the diagnosis of UTI, all patients underwent 99mTc dimercaptosuccinic acid (DMSA) scanning, ultrasonography (US) and intravenous urography (IVU). For the imaging of renal parenchymal infection the sensitivity of IVU and US as compared to DMSA scanning were found to be 9.09% and 25%, respectively. It was concluded that 99mTc DMSA, where available, should be the first step for the accurate diagnosis and follow-up of patients with UTI.

Evaluation of cerebral vasospasm in patients with subarachnoid hemorrhage using single photon emission computed tomography

Cerebral vasospasm (CVS) occurs as a result of the breakdown in cerebral autoregulation mechanisms. Because cerebral vasospasm can occur after subarachnoid hemorrhage (SAH), it is important to evaluate borderline perfusion. Evaluation of borderline vascular insufficiency is important to reduce ischemic complications. In this study 25 patients with SAH were investigated by somatosensory evoked potentials (SEP), computed tomography (CT), digital subtraction angiography (DSA) and single photon emission computed tomography (SPECT) in order to predict borderline ischemic areas. Clinical grades were also correlated with these investigations. Thirteen patients had symptomatic vasospasm and 15 patients had angiographic vasospasm. SPECT showed hypoperfusion in 22 out of 25 patients. CT predicted CVS in 8 of these 22 patients. Our study shows that brain perfusion SPECT is a non-traumatic, non-invasive, non-allergic, inexpensive method for the prediction of cerebral vasospasm. We conclude that brain SPECT with Tc-99m HM-PAO is an accessible technique that can demonstrate varying degrees of regional tissue hypoperfusion in patients with delayed ischemic deficits due to CVS following SAH.

Tc-99m MIBI uptake in pulmonary sarcoidosis. Preliminary clinical results and comparison with Ga-67

During tumor imaging research, the authors incidentally discovered that Tc-99m MIBI is taken up by pulmonary sarcoidosis. In order to evaluate this uptake, they performed Tc-99m MIBI planar and SPECT imaging in 7 patients and compared it with Ga-67. Six out of 7 patients showed evident uptake of Tc-99m MIBI in enlarged hilar lymph nodes. One of the patients, who had been on corticosteroid treatment, showed only faint uptake (negative result), in whom Ga-67 uptake was seen in hilar lymph nodes although it was less evident than the uptake in the other patients. The lymph nodes were better demonstrated with Tc-99m MIBI. The fact that enlarged hilar lymph nodes in a patient on corticosteroid treatment showed faint uptake suggests that Tc-99m MIBI could be helpful for assessing the response to treatment. The preliminary experience in a limited number of patients showed that Tc-99m MIBI is taken up by pulmonary sarcoidosis and it appears to be a potential alternative to Ga-67. Further study is necessary to evaluate its ultimate role in pulmonary sarcoidosis imaging.

Assessment of tumour necrosis and detection of mediastinal lymph node metastasis in bronchial carcinoma with technetium-99m sestamibi imaging: comparison with CT scan

Thirty-eight patients with four major types of bronchial carcinoma were studied to evaluate technetium-99m sestamibi imaging in the assessment of tumour necrosis and the detection of hilar and mediastinal lymph node metastasis. Quantitative analysis was also performed to ascertain whether tumour uptake values correlate with histological types of bronchial carcinoma. Of the patients, 34 showed tumour uptake on planar imaging (n = 38) and 27 on single-photon emission tomography (SPET) (n = 29), the overall sensitivity in the localisation of primary tumour being 89% with planar imaging and 93% with SPET. Four types of tumour uptake pattern were identified: (1) focal uptake, (2) focal uptake with a central hypoactive focus. (3) ring-like uptake and (4) no uptake (negative uptake). Tumour necrosis was diagnosed in 12 patients based upon histopathology (n = 2) and density measurements and type of contrast enhancement on computed tomography (CT) scan (n = 12). Defective tumour uptake was seen in 11 of these patients on planar images (focal uptake with a central hypoactive focus, n = 7; ring-like uptake, n = 2; and no tumour uptake, n = 2) and in 12 patients on SPET (focal uptake with a central hypoactive focus, n = 7, ring-like uptake, n = 3, and no uptake, n = 2). Hilar and mediastinal lymph node involvement was detected in ten patients on CT scan, nine on planar images and 11 on SPET. A total of 26 metastatic lymph nodes were detected on CT scan: 24 of these were seen on planar, and all 26 on SPET images.(ABSTRACT TRUNCATED AT 250 WORDS)

The visualization of granulomatous disease with somatostatin receptor scintigraphy

In-111 labeled pentetreotide scintigraphy was applied to three patients with proven granulomatous disease (two with sarcoidosis, one with tuberculosis). All revealed accumulation of In-111 labeled pentetreotide in the granulomatous lesions, which was considered to be due to the presence of activated lymphocytes in these regions. This method may be of value in assessing the activity and extent of sarcoidosis and tuberculosis.

Plasma endothelin-1 concentrations in patients with Behçet's disease

Plasma Endothelin-1 (ET-1) concentrations were determined by radio immunoassay in 30 patients with Behçet's disease at various stages and 20 healthy subjects. Mean ET-1 plasma concentrations were significantly (p < 0.001) increased in patients with active Behçet's disease (35.99 +/- 5.06 fmol/ml, mean +/- standard error) compared to concentrations found in healthy volunteers (10.98 +/- 0.84 fmol/ml). No difference in plasma ET-1 level was observed between patients with inactive Behçet's disease (12.98 +/- 1.14 fmol/ml) and volunteers. Increased plasma levels of ET-1 in patients with Behçet's disease may be attributable to increased secretion or leakage of this mitogen from injured vascular endothelial cells. These results indicate that ET-1 may play an important pathogenetic role in the development or progression of vasculitis common to Behçet's disease. Plasma concentrations of ET-1 correlates with the activity of illness.

Value of dobutamine technetium-99m-sestamibi SPECT and echocardiography in the detection of coronary artery disease compared with coronary angiography

The value of dobutamine echocardiography and 99mTc-sestamibi SPECT imaging was evaluated as a noninvasive diagnostic method for assessing coronary artery disease (CAD). Twenty-seven patients who underwent coronary angiography were submitted to two separate injections of 99mTc-sestamibi, one under control conditions and the other after reaching a peak dobutamine infusion rate. Simultaneous ECG and echocardiographic monitoring was also performed during stepwise dobutamine infusion. Whereas the overall sensitivity and specificity of dobutamine sestamibi SPECT imaging were 94% and 88%, these values for dobutamine ECG and echocardiography were 61%, 55% and 84%, 88%, respectively. When dobutamine echocardiography and 99mTc-sestamibi SPECT imaging were evaluated together, the diagnostic accuracy reaches almost 100%. Dobutamine echocardiography is of value in determining ischemic threshold earlier than clinical symptoms and allows simultaneous evaluation of ventricular performance and contractile function associated with perfusion abnormalities on 99,Tc-sestamibi SPECT imaging. Our experience shows that 99mTc-sestamibi SPECT imaging, when combined with dobutamine echocardiography, is a safe, practical, well tolerated method with high diagnostic accuracy for the evaluation of CAD.

Dobutamine stress radionuclide ventriculography for the detection of coronary artery disease

Thirty patients were prospectively studied to assess the value of radionuclide ventriculography (RNV) during step-wise dobutamine infusion for the detection of coronary artery disease (CAD). Radionuclide ventriculography was performed under basal conditions and during dobutamine infusion at each 10 micrograms kg-1 min-1 dose increment from 10 to a maximum of 40 micrograms kg-1 min-1. The test response was considered positive if the ejection fraction (EF) decreased by more than 5% or if segmental contraction abnormalities developed. Dobutamine stress testing was well tolerated, no complications and no significant arrhythmia were observed. In nine of 11 patients without CAD, EF increased more than 5% of the rest value and the left ventricular wall motion was normal in 10 of them during dobutamine infusion (specificity 91%). In 18 of 19 patients with CAD, new wall motion abnormalities (WMA) were identified in segments corresponding to the arterial lesions diagnosed by angiography (sensitivity 94%). Ejection fraction response was significantly different in normal subjects and in patients with CAD: 11 +/- 5.9% versus 1.9 +/- 9.5% (P < 0.01). However, abnormal EF response was found in seven of 19 CAD patients and development of new WMA was found to be a more sensitive and specific parameter than EF response for dobutamine RNV. It is concluded that dobutamine RNV is an accurate, widely available and cost-effective test for detecting CAD, especially in patients unable to exercise.

The importance of 99mTc DMSA scanning in the localization of childhood urinary tract infections

The use of 99mTechnetium dimercaptosuccinic acid (99mTc DMSA) scanning for the early diagnosis of upper urinary tract infections has been preferred for a few years. In this research we investigated the use of 99mTc DMSA scanning in the localization of renal parenchymal involvement in urinary tract infection. Twenty-four children presenting with first acute urinary tract infection were studied. Investigations included physical examination, white blood cell count (WBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), antibody-coated bacteria (ACB) and early 99mTc DMSA scanning. 99mTc DMSA scanning was taken as the gold standard method in determining renal parenchymal inflammation. According to the 99mTc DMSA scanning the sensitivity of clinical findings was 57.14%, WBC 23.80%, ESR 33.33%, CRP 14.28% and ACB 71.42% in the localization of urinary tract infection. We propose early 99mTc DMSA scanning performed around the time of infection as a good technique for localization of the level of infection in the urinary tract.

Role of bone scanning in the management of non-united fractures: a clinical study

Technetium-99m methylene diphosphonate (99mTc-MDP) bone scintigraphy was performed in 45 patients (42 male and 3 female) with established non-united fractures to predict the healing response to pulsing electromagnetic field stimulation therapy. The bone scans revealed 3 different scintigraphic patterns. The most frequent pattern was an increased uniform uptake of the tracer at the non-union site (group 1). The second pattern was increased activity at the bone ends with a photon-deficient area between the fracture sites (group 2a) or a generalized decrease in the radionuclide concentration in the region of bone fragments (group 2b). When the scintigraphic pattern did not fit either of the two patterns or when the presence of the cold area between the bone fragments could not be judged with certainty, it was called indeterminate (group 3). All patients underwent pulsing electromagnetic field stimulation. The healing rate was 87.5% and 42.8% in group 1 and group 3 patients, respectively. None of the group 2 patients had any evidence of healing, and they all underwent surgical exploration, revealing complicated non-unions. We conclude that 99mTc bone scintigraphy is a useful tool in determining complicated non-unions and selecting the proper therapy mode.

Visualization of bladder diverticulum during Tc-99m DTPA renal scintigraphy

An eight-year-old boy with recurrent urinary infection underwent Tc-99m DTPA renal scintigraphy for the evaluation of renal function. Stasis of the tracer was observed in the pelvocalyceal systems of both kidneys. Intravenous diuretic was administered to evaluate a possible mechanical obstruction. During the course of the study, a well-defined, round area of activity extended from the bladder which was subsequently confirmed to be a diverticulum on voiding cystourethrogram and at surgery.

Clinical experience with Tc-99m MIBI imaging in patients with malignant tumors. Preliminary results and comparison with Tl-201

Tc-99m MIBI imaging was performed in 34 patients with histopathologically proven malignant tumors. The study was performed in two steps. In the first step, only Tc-99m MIBI imaging was performed (Group 1). In the second step, both Tc-99m MIBI and Tl-201 imaging were performed for comparison (Group 2). Seventeen patients were studied in each step. The size of the smallest primary tumor (breast cancer) was 15 x 10 mm, and that of the largest (lung cancer) was 145 x 130 mm. Of the 34 patients, 26 showed Tc-99m MIBI uptake at the tumor site. In Group 1, 12 patients showed Tc-99m MIBI tumor uptake, but no uptake was detected in five patients (squamous cell carcinoma of the esophagus, teratoma of the testis, nonHodgkin's lymphoma, and squamous cell carcinoma of the lung). In Group 2, 13 patients showed both Tc-99m MIBI and Tl-201 uptake at the tumor site, but one patient with breast cancer showed only Tc-99m MIBI uptake, and three patients showed no Tc-99m MIBI and Tl-201 uptake (embryonal cell carcinoma of the testis, hepatocellular carcinoma). The overall sensitivity of Tc-99m MIBI imaging was 76.4%. In Group 2, the sensitivity was 82.3% for Tc-99m MIBI and 76.4% for Tl-201. Our preliminary clinical experience suggests that Tc-99m MIBI can be helpful in localizing malignant tumors and that its sensitivity is slightly higher than Tl-201.

Unexpected uptake of technetium 99m hexakis-2-methoxy-isobutylisonitrile in giant lymph node hyperplasia of the mediastinum (Castleman's disease)

The case of a patient with giant lymph node hyperplasia of the mediastinum who unexpectedly showed focal uptake of technetium 99m hexakis-2-methoxyisobutylisonitrile (99mTc-MIBI) is presented in this article. The patient was included in our research programme of tumor imaging with 99mTc-MIBI because the appearance of the mass on the chest radiogram and CT scan resembled a mediastinal tumour. Final diagnosis of giant lymph node hyperplasia was achieved through histopathological examination of the surgically removed lymph node.

Technetium-99m-MIBI and thallium-201 uptake in pulmonary actinomycosis

A patient with pulmonary actinomycosis who unexpectedly showed focal uptake of technetium-99m-hexakis-2-methoxy isobutyl isonitrile and thallium-201 is presented. The appearance of the lesion on the chest radiograph and x-ray CT scan resembled a mediastinal tumor. The diagnosis of pulmonary actinomycosis was achieved by histopathologic examination of the surgically removed mass.