Comparison of dipyridamole Tc-99m myocardial imaging with dipyridamole electrocardiogram in detecting coronary artery disease

The authors compared the results of dipyridamole myocardial-SPECT (D-ECT) with dipyridamole electrocardiogram (D-ECG) in detecting coronary artery disease (CAD). According to the result of coronary artery angiogram. We analysed the results of D-ECT and D-ECG in 62 patients. In detecting CAD, the sensitivity and specificity of D-ECT were 89%, and 92%, while those of D-ECG were 54% and 76% respectively. In detecting single double, triple vessel diseases, the sensitivity of D-ECT was 76%, 100% and 100% respectively. The sensitivity of D-ECG was 35%, 73% and 67% respectively. In identifying left anterior descending, left circumflex and right coronary artery, the sensitivity of D-ECT was 73%, 80% and 80% respectively, while that of D-ECG was 54%, 20% and 25% respectively. The results showed that D-ECT was better than D-ECG in diagnosing CAD.     

Fast acquisition of myocardial SPECT images with Tc-99m sestamibi for the diagnosis of coronary artery disease

BACKGROUND: Shortening the acquisition time for myocardial single-photon emission computed tomographic (SPECT) imaging increases patient comfort and laboratory throughput. The purpose of this study was to compare the diagnostic accuracy for coronary artery disease detection of myocardial SPECT images acquired in 5 to 10 minutes versus 25 minutes using Tc-99m methoxyisobutylisonitrile (Tc-99m sestamibi) and a single-head gamma camera. METHODS AND RESULTS: Forty-one subjects had a standard 1-day rest/stress Tc-99m sestamibi myocardial SPECT study. Two sets of rest and stress images were acquired on the same day for each subject. One set of images was acquired with a 5- to 10-minute fast acquisition protocol; the second set of images was acquired with a 25-minute standard protocol. The accuracies of the fast and standard protocols for identifying individuals with and without coronary artery disease were equivalent. Accuracy was 76% for the fast protocol and 73% for the standard protocol in individuals with at least one coronary stenosis > or = 70%. The accuracies of the two protocols for identifying individual coronary arteries with stenoses > or = 70% also were equivalent. Accuracy was 77% for the fast protocol and 74% for the standard protocol. CONCLUSIONS: SPECT myocardial images may be acquired in as little as 5 to 10 minutes using Tc-99m sestamibi and a 1-day rest/stress protocol. Accuracy is equivalent to that attained in studies with longer imaging times.     

Stress technetium-99m tetrofosmin myocardial scintigraphy: a new one-hour protocol for the detection of coronary artery disease

The primary objective of this study was to evaluate in a random double-blind design, the sedative and behavioural responses of children undergoing outpatient paediatric dental procedures receiving either chloral hydrate (CH) alone or in combination with hydroxyzine. Forty American Society of Anaesthesiologists class I children (21 to 36 months of age) were randomly allocated to receive either 70 mg/kg CH alone or with 2 mg/kg hydroxyzine. The degree of crying, movement and overall behaviour was evaluated during treatment at different times. The combination of chloral hydrate/hydroxyzine (CH/H) significantly decreased crying and movement in relation to the effect induced by CH alone (p < 0.05) only at 45-60 min following the insertion of a rubber dam, whereas the overall behavior in both groups was no different throughout the dental procedures. In conclusion, our study demonstrated that hydroxyzine increased the effect of CH. However, because of the presence of high rates of oxygen desaturations and of deep sedation, careful use of this drug combination should be stressed.     

Scintigraphic evaluation of malignant melanoma lesions with Tc-99m tetrofosmin

Two cases of malignant melanoma (primary and metastatic lesions) imaged with Tc-99m tetrofosmin are reported. One patient showed intense uptake in a primary skin lesion of the thorax, and the other patient had accumulation in skin, cerebellum, breast, and lymph node metastases. Like Tc-99m MIBI, Tc-99m tetrofosmin imaging may be of clinical relevance in the evaluation of suspicious skin lesions and in patients with known cutaneous malignant melanoma in the assessment of recurrent disease during follow-up evaluation.     

Technetium-99m tetrofosmin imaging in thyroid diseases: comparison with Tc-99m-pertechnetate, thallium-201 and Tc-99m-methoxyisobutylisonitrile scans

Technetium-99m tetrofosmin is a lipophilic phosphine used for myocardial perfusion imaging. Biodistribution studies have shown significant thyroid uptake of tetrofosmin and preliminary reports have suggested that tetrofosmin imaging may be of value in patients with thyroid cancer. In this study, tetrofosmin whole-body scintigraphy was performed in 35 patients with evidence of thyroid diseases. All patients underwent laboratory evaluation of thyroid function as well as 99mTc pertechnetate scan, thallium-201 (n=16) 99mTc-methoxyisobutylisonitrile (MIBI) (n=19) whole-body studies. Thyroid images were semi-quantitatively analysed by a 4-point score: 0=no significant uptake; 1=uptake increased as compared to background activity, but inferior to normal thyroid tissue; 2=uptake equal to normal thyroid tissue; 3=uptake superior to normal thyroid tissue. Pathology examinations were obtained. A total of 41 thyroid nodules were detected, of which 15 were goitre nodules, 13 adenomas and 13 malignant lesions. In goitre nodules, concordant results of tetrofosmin and pertechnetate uptake (score 1 or 0) were observed in the majority of lesions (87%). In function adenomas (n=10), both tetrofosmin uptake and pertechnetate uptake were score 3. In non-function adenomas (n=3), tetrofosmin uptake was score 3, while pertechnetate uptake was score 0. In six malignant lesions, tetrofosmin uptake was score 3, while pertechnetate uptake was score 0; in the other seven lesions, where a prevalence of goitre abnormalities was observed, results of tetrofosmin and pertechnetate uptake were similar (score 0 or 1). In seven (70%) of the ten patients with malignant nodules, whole-body tetrofosmin images showed increased abnormal uptake in a total of 28 extra-thyroid tumour sites, as subsequently confirmed by other techniques. When tetrofosmin images were compared to 201Tl and 99mTc-MIBI scans, concordant results were observed in all cases. In conclusion, tetrofosmin imaging may be particularly useful to characterize and stage patients with malignant thyroid nodules; it shows similar results to thallium but provides better image quality. Comparable findings were observed between tetrofosmin and MIBI studies. Thus, tetrofosmin may be an alternative to thallium and MIBI in the aforementioned patients.     

Interictal SPECT with Tc-99m HMPAO studies in migraine patients

BACKGROUND: Creating a defunctioning stoma for anorectal disease in patients in whom no resection or anastomosis is required appears eminently suited for laparoscopic techniques, with the intended advantages of early recovery, reduced pain, and avoidance of a laparotomy. OBJECTIVES: The study contained herein was undertaken to determine the feasibility of laparoscopic defunctioning stoma formation using a three-port technique (including one at the stoma site) and to compare initial results with a historical control group. METHODS: Duration of operation (anesthetic plus surgery), the time to tolerance of a liquid and then a solid diet, time to passage of flatus and feces, patient morphine requirements in the first 48 hours, and day of discharge were documented. RESULTS: Nineteen laparoscopic stomas were attempted (3 converted to open) and 23 open stomas were formed in the control group. The laparoscopic stoma group had lower morphine requirements (mean, 47.7 vs. 89.9 mg; P < 0.01), an earlier tolerance of both liquid (mean, 2.1 vs. 3.7 days; P < 0.01) and solid diets (mean, 3.6 vs. 5.5 days; P < 0.001), and an earlier time to passage of both flatus (mean, 2.2 vs. 3.6 days; P < 0.001) and feces (mean, 3.7 vs. 5.6 days; P < 0.001). Operating time was longer for the laparoscopic group (mean, 176 vs. 104 minutes; P < 0.001), whereas median time to discharge from hospital was shorter (median, 8 vs. 11 days; P = 0.014). Postoperative 30-day morbidity occurred in 1 of 19 laparoscopic group patients and 4 of 23 open group patients. CONCLUSIONS: In this select group of patients requiring defunctioning stoma only, laparoscopic surgery is feasible and safe and may have advantages over open procedures of less pain, earlier tolerance of diet, earlier return of bowel function, and a shorter median length of stay.     

Diagnosis of orbital cavernous hemangioma with Tc-99m RBC SPECT

The authors report two cases of orbital cavernous hemangioma diagnosed by Tc-99m RBC SPECT. Tc-99m RBC SPECT showed a typical scintigraphic pattern commonly seen in hepatic hemangioma in which there is intense focally increased uptake on delayed SPECT images. Tc-99m RBC SPECT in orbital cavernous hemangioma may be as useful a diagnostic modality as in hepatic hemangioma.     

Comparative myocardial uptake of technetium-99 m sestamibi and technetium-99m tetrofosmin one hour after stress injection

Technetium-99m sestamibi and 99mTc-tetrofosmin are at present the preferred tracers for simultaneous assessment of myocardial perfusion and function by gated single-photon emission tomography (SPET). The aim of this work was to compare sestamibi and tetrofosmin myocardial uptake 1 h after stress injection. Consecutive unselected patients were studied either with sestamibi or with tetrofosmin on a random basis, until at least 100 patients had been enrolled for each gender and tracer. Stress was obtained by dipyridamole or exercise or combined dipyridamole + exercise; in the latter cases, exercise was sustained for at least 1.5 min after tracer injection. Injected activity was similarly adjusted to body weight. For each patient, imaging began 60-75 min after injection. All SPET projections were summed; due to the acquisition technology ("roving zoom", i.e. a mobile zoom), the heart always appeared at the centre of the frame in all projections and in the sum image. Thus minimal lung background contamination could be assumed in an elliptic region of interest placed over the heart on the sum image. Three indexes were analysed: total myocardial counts (Sum), mean myocardial pixel (Mean) and maximum myocardial pixel (Max). Four patient groups were analysed: males with sestamibi or tetrofosmin (MS: n = 189 and MT: n = 157), females with sestamibi or tetrofosmin (FS: n = 101 and FT: n = 104). MS and MT groups were comparable for physical variables, maximum heart rate and stress type, as were the FS and FT groups. Sum, Mean and Max were significantly higher with sestamibi (P = 0.0001 by ANOVA). Comparing MS vs MT and FS vs FT, mean values +/- SD were as follows: for Sum (kcounts) 750+/-184 vs 652+/-166, and 707+/-202 vs 594+/-189; for Mean (counts) 4517+/-1171 vs 4107+/-898, and 4908+/-1119 vs 4144+/-1025; and for Max (counts) 6471+/-1654 vs 5794+/-1312, and 7318+/-1886 vs 6152+/-1684. The mean gain with sestamibi was +15%, +10% and +12% in males, and +19%, +18% and +19% in females. Similar differences were found within each stress type subgroup. No gender-specific effect was found for Mean, so the overall mean gain was calculated for Mean: +13% for sestamibi vs tetrofosmin. These findings are consistent with other published smaller sample series. Possible differences between tracers with regard to residual activity in syringes were ruled out by an additional experiment. In summary, we found significantly higher myocardial counts with sestamibi than with tetrofosmin, in males as well as in females.     

Technetium-99m teboroxime regional myocardial washout in subjects with and without coronary artery disease

The aim of this study was to test the hypothesis that regional myocardial washout of technetium-99m teboroxime is slowed in the presence of coronary stenosis. Washout was assessed in 33 catheterized patients and in 13 with a low likelihood of coronary artery disease, using a triple detector camera and dynamic single-photon emission computed tomography, with serial 1-minute acquisitions after injection of 20 to 25 mCi of teboroxime at the third minute of adenosine-induced hyperemia. Washout was measured as the percent change in counts between the first, second and third minutes after injection, as measured in 6 short-axis myocardial regions of interest. Myocardial regions were classified as ischemic (> or = 50% diameter stenosis and no prior myocardial infarct), infarcted, normal (no significant coronary stenosis) or "low likelihood" (from the 13 patients with a low likelihood of coronary artery disease). Teboroxime washout was significantly (p < 0.001) slowed in the ischemic myocardium (12.7 +/- 8.3%) compared with the normal (18.5 +/- 5.7%), low-likelihood (17.8 +/- 6.1%) and infarcted (17.8 +/- 4.4%) zones. There was regional variability in washout rates (% washout/min), with the anterior wall having the lowest (13.8 +/- 3.4%/min) and the inferior wall the highest (20.7 +/- 7.9%/min) values. In regard to individual coronary territories, 21 of 41 ischemic, noninfarcted territories (51%) had abnormal washout compared with 3 of 43 normal territories (7%) (p = 0.001). In conclusion, regional washout of teboroxime is detectably slowed in ischemic, noninfarcted myocardium. The clinical value of washout analysis in teboroxime single-photon emission computed tomography warrants further investigation.     

Tc-99m HMPAO brain SPECT compared to CT and EEG after seizures in childhood

Twenty-one children with various seizure disorders were studied using Tc-99m HMPAO brain SPECT, cranial CT, and electroencephalography (EEG). The rates of pathologic findings on SPECT, CT, and EEG were 67%, 38%, and 52%, respectively. SPECT showed congruent, or more extensive, lesions in all eight patient with CT lesions. Six of the 13 children who had normal CT results, had abnormal SPECT study results. In this postictal series, 4 of the 14 abnormalities detected in the first SPECT study that was applied within 24 hours of a seizure, were in the form of hyperperfused areas. Eight of the 14 abnormal first SPECT studies had become normal by the second SPECT. We conclude that, with respect to the depiction of some kind of abnormality, HMPAO brain SPECT is superior to CT and EEG, and considerable changes in brain perfusion are likely to occur over a period of a few weeks.     

Combined thallium-201 myocardial with technetium-99m-HMPAO brain SPECT: myocardial ischemia induced by acetazolamide in severe coronary artery disease

IgM anti-myelin-associated glycoprotein (anti-MAG)/sulfated glucuronyl paragloboside (SGPG) antibody is found in some patients with chronic polyneuropathy (CP). An antigen-driven process is considered to induce this autoantibody, but the agent has yet to be identified. It has been reported that sera from cytomegalovirus (CMV)-infected patients contained anti-SGPG antibody. To clarify the mechanism of the production of the anti-MAG/SGPG antibody, we investigated CMV DNA in sera from 26 patients with IgM anti-MAG/SGPG antibody-positive CP. Twenty-three (88%) had CMV DNA. The positive frequency was significantly higher than the frequencies in sera from patients with IgM anti-MAG/SGPG-negative CP, the other disease controls, and the normal control subjects. There were no statistical differences in the frequencies of Epstein-Barr virus DNA between anti-MAG/SGPG-positive and anti-MAG/SGPG-negative CP and between anti-MAG/SGPG-positive CP and each disease control. Moreover, no herpes simplex virus 1 DNA was detected in the sera from patients with anti-MAG/SGPG-positive CP. The strong correlation of anti-MAG/SGPG-positive CP with the presence of serum CMV DNA suggests that CMV infection induces the IgM anti-MAG/SGPG antibody.     

The usefulness of Tc-99m HMPAO labeled WBC SPECT in eosinophilic gastroenteritis

Tc-99m HMPAO labeled WBC SPECT was performed in 5 patients with eosinophilic gastroenteritis before and after successful medical therapy. The imaging findings were graded according to the following imaging scheme; grade 0, no uptake; grade 1, uptake < bone marrow; grade 2, uptake < liver; grade 3, uptake > liver. In no patient was the diagnosis made radiologically or with colonoscopy. The sites of involvement were identified with Tc-99m HMPAO WBC imaging in all patients before treatment and the radionuclide imaging studies were all negative after therapy.     

Assessing myocardial perfusion in coronary artery disease with magnetic resonance first-pass imaging

MRFP perfusion imaging can now be used clinically on most MR scanner systems (1.0 to 1.5 T). The current experimental data demonstrate that MRFP imaging allows the quantitative assessment of myocardial blood flow changes and accurate measurements of collateral flow, including changes in the collateral dependent zones. Certain protocols, however, as outlined here have to be followed to obtain all the possible diagnostic information. Based on the current data on MRFP imaging, it is realistic to anticipate that MRFP imaging in combination with cine or tagging MR imaging will provide clinicians with better methods to distinguish stunned and hibernating, from nonviable myocardium and obtain better outcome data. Dedicated MR scanners are now being designed to meet the needs for MR imaging of patients with coronary artery disease. These scanners, small in size and with better patient access, make placement near the coronary care unit or catheterization laboratory feasible. This is a major step toward enhancing the utility of this new technique by providing the necessary infrastructure for scanning large numbers of patients. The main obstacle to wider use of these new diagnostic tools to assess perfusion is the lack of a large clinical database because there have not yet been major multicenter trials. With the development of novel intravascular contrast agents, however, larger trials are planned that should provide the clinical data mandatory for full integration of MRFP imaging into clinical practice. In particular, the development of dedicated and user-friendly perfusion analysis software will create the means to evaluate MR perfusion data accurately in large patient populations. These studies need to be conducted in a collaborative fashion by cardiologists, heart surgeons, and radiologists to be fully accepted by health care providers in an increasingly cost-averse and competitive health care environment.     

Technetium 99m tetrofosmin parathyroid imaging. Results with double-phase study and SPECT in primary and secondary hyperparathyroidism

RATIONALE AND OBJECTIVES: The aim of our study was to evaluate the sensitivity, specificity, and positive predictive value (PPV) of technetium 99m (99mTc) tetrofosmin double-phase scintigraphy and single-photon emission computer tomography (SPECT) in preoperative localization of parathyroid adenoma in case of primary and secondary hyperparathyroidism (HPT). METHODS: Sixty-eight consecutive patients biochemically or sonographically suspected of parathyroid adenoma were included in our study. Apart from biochemical analysis of serum calcium, phosphate, and intact parathyroid hormone, double-phase scintigraphy was performed in each patient 5 and 45 minutes after injection of 370 MBq 99mTc tetrofosmin, followed by SPECT imaging. In consciousness of the scintigraphic results, ultrasound of the neck was performed as well to exclude false-positive results due to thyroid adenomas. RESULTS: Depending on the results of the biochemical analysis in combination with the results of the scintigraphic and ultrasound examination, the patients were classified retrospectively into three groups: group A with primary HPT (n = 35), group B with secondary HPT (n = 13), and group C without any biochemical suspicion of primary or secondary HPT (n = 20). In group A, double-phase study localized 25 of 36 (69.2%) parathyroid adenomas (one double adenoma) as against 34 of 36 (94.4%) with SPECT. Nine adenomas could be visualized only by SPECT. The reason for nonvisualization on planar scans was suspected to be an ectopic location in 2 cases (retrotracheal dislocation, retrovascular dislocation), a maximal diameter less than 15 mm (9-13 mm) in 6 cases, and oxyphilic-cell-poor cellularity in 1 case. Four false-positive retention (3 thyroid adenomas and 1 papillary thyroid carcinoma) were observed. SPECT showed a sensitivity of 94.4%, a specificity of 85%, and a PPV of 91.9% in biochemically suspected primary HPT. In group B, planar scintigraphy demonstrated 12 hyperplastic glands in 5 of 13 patients, and SPECT demonstrated 20 hyperplastic parathyroid glands in 8 out of 13 patients, which corresponds to a sensitivity of 38% and 61.5%, respectively. CONCLUSIONS: Technetium 99m tetrofosmin seems to be a promising alternative tracer with similar capabilities to 99mTc sestamibi in localization of parathyroid adenoma. SPECT showed clear advantages in terms of sensitivity over planar scintigraphy and should be used at least in cases with poor or no uptake in double-phase study. In endemic goiter areas, ultrasound of the neck should be performed to exclude false positive retention in thyroid adenomas. Technetium 99m tetrofosmin, like 99mTc sestamibi, is not ideal for localization of hyperplastic glands in secondary hyperparathyroidism because of low sensitivity.     

Use of exercise technetium-99m sestamibi SPECT imaging to detect residual ischemia and for risk stratification after acute myocardial infarction

The clinical presentation, electrocardiographic findings, and technetium-99m sestamibi single-photon emission computed tomography (SPECT) imaging results of 134 consecutive patients who underwent nuclear exercise testing within 14 days of an acute myocardial infarction (AMI) were correlated with cardiac events over a 15 +/- 10-month follow-up. Whereas only 23 patients (17%) had chest pain and 31 (23%) had ischemic ST-segment depression during exercise, 94 (70%) had ischemia on SPECT (p < 0.001). On follow-up, 13 patients experienced a cardiac event: 7 were rehospitalized for unstable angina, 3 had recurrent AMI, and 3 died of cardiac causes. Ischemia on the sestamibi images identified 11 of these patients (85%), whereas chest pain identified only 3 (23%, p = 0.006), and electrocardiographic ischemia identified only 4 (31%, p = 0.017). The presence of either ischemia as seen on SPECT or defects in multiple vascular territories identified 12 patients (92%) with an event, including all who had cardiac death. By Cox regression analysis of clinical, stress, and image parameters, the number of ischemic defects on SPECT was the only significant correlate of a future event (chi-square = 4.62, p = 0.03), and patients with > or = 3 reversible sestamibi defects had an event rate of 38%. The extent of ischemia as seen on nuclear imaging remained a strong correlate (p = 0.008) of an event in the 54 patients (40%) who had received thrombolytic therapy. Thus, exercise technetium-99m sestamibi SPECT after AMI frequently reveals residual ischemia, and is better than clinical data, symptoms, and stress electrocardiographic data in identifying patients who will have a subsequent cardiac event.