Tc-sestamibi SPECT Research Articles

Four-dimensional computed tomography as first-line imaging in primary hyperparathyroidism, a retrospective comparison to conventional imaging in a predominantly single adenoma population

BackgroundTo determine the use of four-dimensional CT as first-line imaging compared to the traditional combination of ultrasound and [99mTc]Tc-Sestamibi SPECT.Materials and methodsRetrospective review of preoperative imaging in patients with primary hyperparathyroidism, who underwent parathyroidectomy between 2012 and 2021. In one group, the combination ultrasound and [99mTc]Tc-Sestamibi SPECT was used as first-line imaging (n = 54), in the other group four-dimensional CT was the first-line imaging modality (n = 51). Sensitivity and positive predictive value were calculated on patient, lateralisation and localisation level. The need for additional imaging was also assessed for both groups.ResultsFour-dimensional CT had a significantly higher sensitivity compared to the combination of ultrasound/[99mTc]Tc-Sestamibi SPECT on patient and localisation level (70.6% vs. 51.9%, p = 0.049 and 60.8% vs. 35.2%, p = 0.009 respectively). Sensitivity for lateralisation also appeared higher, but did not reach significance (62.7% vs. 44.4%, p = 0.060). Positive predictive value was not significantly higher for four-dimensional CT compared to ultrasound and [99mTc]Tc-Sestamibi SPECT (88.9% vs. 85.7% for lateralisation and 86.1% vs. 67.9% for localisation respectively). Additional imaging was required in 14 patients with four-dimensional CT as first-line imaging (27.4%) consisting of 2 ultrasound/[99mTc]Tc-Sestamibi SPECT and 13 [18F]fluorocholine PET/CT, compared to 24 patients with ultrasound/[99mTc]Tc-Sestamibi SPECT as first-line imaging (44.4%), requiring 22 four-dimensional CT and 9 [18F]fluorocholine PET/CT.ConclusionsFour-dimensional CT as the sole first-line parathyroid imaging modality had higher sensitivity than the combination of ultrasound and [99mTc]Tc-Sestamibi SPECT, therefore requiring fewer additional procedures. Although the most costly, [18F]fluorocholine PET/CT was the most effective technique to localise parathyroid adenoma in case all other imaging was negative.

The Appropriate Acquisition Time Interval Following Injection of 99mTc-Sestam ibi with Water Protocol in Single Photon Emission Computed Tomography Myocardial Perfusion Imaging: First Experience in Indonesia

<p><strong>Introduction: </strong>According to EANM/ESC guideline, image acquisitions in stress test should be begun at 30-60 minutes after tracer administration. Our center is a referral hospital for nuclear medicine imaging with many patients but limited number of gamma camera. The shorter time between injection of radiopharmaceutical and imaging acquisition will add to the number of examinations that can be performed. The aim of this study was to evaluate the appropriate acquisition time interval with water protocol in <sup>99m</sup>Tc-Sestamibi SPECT myocardial perfusion imaging.</p><p><strong>Methods: </strong>Patients who were referred to undergo stress MPI between October 2020 to December 2020 were included in this study. Cardiac stress procedure was performed using treadmill with modified Bruce Protocol. Subjects drank a total of 330 mL water following <sup>99m</sup>Tc-Sestamibi injection. Image acquisitions were performed 10 and 30 minutes afterwards. Quantitative assessment was done by calculating target background ratio (TBR). Statistical analysis was performed using student t-test with Microsoft Excel version 2019. <em>P</em>-value < 0.05 was considered to be statistically significant.</p><p><strong>Result: </strong>Thirty out of 35 subjects were included in this study. Sixteen of them are male and 14 are female with a mean age of 48.7 years old (28 – 80). Mean target background uptake ratio (TBR) in 10- and 30-minutes images were 0.67 (0.44 – 1.11) and 0.76 (0.43 – 1.18) respectively (<em>p-</em>value = 0.15).</p><p><strong>Conclusion: </strong>There was no significant difference of target to background ratio between 10- and 30-minutes acquisition time interval following injection of <sup>99m</sup>Tc- Sestamibi with water protocol in myocardial perfusion imaging.</p>

18F-Fluorocholine PET/CT Is More Sensitive Than 11C-Methionine PET/CT for the Localization of Hyperfunctioning Parathyroid Tissue in Primary Hyperparathyroidism.

Preoperative molecular imaging is paramount to direct surgery in primary hyperparathyroidism (pHPT). We investigated the diagnostic performance of 18F-fluorocholine (18F-FCH) PET/CT compared with 11C-methionine (11C-MET) PET/CT for localization of hyperfunctioning parathyroid tissue in patients with pHPT and negative or inconclusive 99mTc-sestaMIBI (99mTc-MIBI) SPECT findings. Methods: Fifty-eight patients with biochemical evidence of pHPT and negative or inconclusive 99mTc-MIBI SPECT findings were referred for presurgical detection and localization of hyperfunctioning parathyroid tissue by 11C-MET and 18F-FCH PET/CT. The PET/CT results were classified into 3 categories (positive, inconclusive, or negative) based on the nodular aspect of tracer uptake and the visualization of corresponding nodules on CT. The PET/CT results were correlated with the surgical and histopathologic findings, which were used as the gold standard. Results: Fifty-three patients were included for analysis. 18F-FCH PET/CT was positive in 39 patients (74%), inconclusive in 5 (9%), and negative in 9 (17%), compared with 25 (47%), 12 (23%), and 16 (30%), respectively, for 11C-MET PET/CT. 18F-FCH localized 11 additional foci (6 positive and 5 inconclusive), compared with 11C-MET. Twenty-six patients (sex ratio, 10/16 M/F) underwent surgery, with resection of 31 lesions (22 adenomas, 6 hyperplastic glands, and 3 carcinomas) and 1 normal gland. At follow-up, 21 patients (81%) were considered cured after surgery, whereas 3 patients (12%) had persistence of hypercalcemia. With inconclusive cases being considered negative, 18F-FCH PET/CT correctly localized 26 lesions in 24 of 26 patients (92%), compared with 16 lesions in 15 of 26 patients (58%) localized by 11C-MET PET/CT. Per-patient-based sensitivity and positive predictive value were 96% and 96%, respectively, for 18F-FCH and 60% and 94%, respectively, for 11C-MET (P < 0.0001). Per-lesion-based sensitivity and positive predictive value were 84% and 90%, respectively, for 18F-FCH and 52% and 94%, respectively, for 11C-MET (P < 0.0001). Conclusion: In the presence of biochemical evidence of pHPT with negative or inconclusive 99mTc-MIBI SPECT findings, 18F-FCH PET/CT performs better than 11C-MET PET/CT for the detection of pathologic parathyroid tissue, allowing localization of parathyroid adenoma or hyperplasia in 96% of patients.

English

BACKGROUND The differentiation of tumour progression from treatment-induced changes is critical in evaluating response to therapy among patients with gliomas. Although conventional magnetic resonance imaging (MRI) is invaluable in the overall assessment of such lesions, it is often difficult to differentiate between these two entities. We wanted to evaluate the role of contrast-enhanced MRI (CE MRI) and magnetic resonance spectroscopy (MRS) and correlation with 99 m Tc Sestamibi single-photon emission tomography (SPECT) in differentiating tumour progression from post-therapy changes in patients with glioma. METHODS This was a cross-sectional study. Being a rare disease, all adult patients (25 in number) with brain glioma reporting to the hospital for over a period of 12 months were included in the study. CE MRI, MRS and SPECT were performed at three months, six months and 12 months’ post-surgery and radiotherapy. The ratios for choline (Cho) / N-acetyl aspartate (NAA) and choline (Cho) creatine (Cr) were obtained from the areas suspicious for tumour progression on CE MRI and were correlated with the presence or absence of uptake on SPECT. These findings were correlated with the patients’ clinical course and tumour histopathology. RESULTS Both choline (Cho) / N-acetyl aspartate (NAA) and choline (Cho) / creatine (Cr) ratios had high detection rates for tumour progression when cut-off values of &gt; 1.75 were used. For the Cho / NAA ratio, the sensitivity and specificity were 93.7 % and 100 %, respectively. The sensitivity and specificity for the Cho / Cr ratio were 81.3 % and 88.9 %, respectively. The sensitivity and specificity of 99 m Tc Sestamibi SPECT were 87.5 % and 100 %, respectively. CONCLUSIONS MRS and SPECT have high sensitivity and specificity for diagnosing tumour progression and must be used in conjunction with conventional CE MRI in the posttherapy setting. KEYWORDS Glioma, Progression, Post-Therapy Changes, MRI, MRS, SPECT

Reoperations for primary hyperparathyroidism—improvement of outcome over two decades

Reoperations (R-PTX) for primary hyperparathyroidism (pHPT) are challenging, since they are associated with increased failure and morbidity rates. The aim was to evaluate the results of reoperations over two decades, the latter considering the implementation of Tc(99m)sestamibi-SPECT (Mibi/SPECT), intraoperative parathormone (IOPTH) measurement, and intraoperative neuromonitoring (IONM). Data of 1,363 patients who underwent surgery for pHPT were retrospectively analyzed regarding reoperations. Causes of persistent (p) pHPT or recurrent (r) pHPT, preoperative imaging studies, surgical findings, and outcome were analyzed. Data of patients who underwent surgery between 1987 and 1997 (group 1; G1) and between 1998 and 2008 (group 2; G2) with the use of Mibi/SPECT, IOPTH, and IONM were evaluated. One hundred twenty-five patients with benign ppHPT (n = 108) or rpHPT (n = 17) underwent reoperations (R-PTX). Group 1 included 54, group 2 71 patients. Main cause of ppHPT (G1 = 65 % vs. G2 = 53 %) and rpHPT (G1 = 80 % vs. G2 = 60 %) was the failed detection of a solitary adenoma (p = 0.2). Group 1 patients had significantly less unilateral/focused neck re-explorations (G1 = 23 % vs. G2 = 57 %, p = 0.0001), and more sternotomies (G1 = 35 vs. G2 = 14 %, p = 0.01). After a median follow-up of 4 (range 0.9-23.4) years, reversal of hypercalcemia was achieved in 91 % (G1) and in 98.6 % in group 2 (p = 0.08, OR 7.14 [0.809-63.1]). The rates of permanent recurrent laryngeal nerve palsy (G1 = G2 = 9 %, p = 1) and of postoperative permanent hypoparathyroidism (G1 = 9 % vs. G2 = 6 %, p = 0.5) were not significantly different. Other complications such as wound infection, postoperative bleeding, and pneumonia were significantly lower in group 2 (p < 0.001). Nowadays, cure rates of R-PTX are nearly the same as in primary operations for pHPT. These results can be achieved in high-volume centers by routine use of well-established preoperative Mibi/SPECT and US in combination with IOPTH. However, morbidity is still considerably high.

Efficacy of 99mTc-sestamibi SPECT/CT for minimally invasive parathyroidectomy: comparative study with 99mTc-sestamibi scintigraphy, SPECT, US and CT

We evaluated the efficacy of (99m)Tc-sestamibi SPECT/CT for planning minimally invasive parathyroidectomy (MIP), comparing with dual phase (99m)Tc-sestamibi scintigraphy, (99m)Tc-sestamibi SPECT and conventional imaging (US and CT). Thirty-one patients (M:F = 10:21, range 35-78 years old) who showed high serum parathyroid hormone (intact PTH) level were included. (99m)Tc-sestamibi scintigraphy was performed 15 and 150 min after injection of (99m)Tc-sestamibi (555 MBq), and (99m)Tc-sestamibi SPECT/CT was obtained just after the delayed scan. Comparison study between imaging modalities was done by patient-based and lesion location-based analysis. The location of the lesion was confirmed by the operative finding. An operation was performed in 24 patients. Seven patients had normal (99m)Tc-sestamibi SPECT/CT, and followed for more than 6 months after SPECT/CT. Among 24 patients, parathyroid adenoma was detected in 19 patients and the other 5 had parathyroid hyperplasia (total 35 lesions). (99m)Tc-sestamibi scintigraphy detected abnormal uptake in 15 patients with 24 lesions. Conventional imaging identified abnormal findings in 17 patients with 27 lesions. SPECT detected abnormal findings in 18 patients with 27 lesions. SPECT/CT identified abnormal findings in 24 patients with 35 lesions. SPECT/CT demonstrated 100 % sensitivity in a patient-based analysis. SPECT/CT exhibited significantly better sensitivity than (99m)Tc-sestamibi scintigraphy, SPECT and conventional imaging (p < 0.05). All lesion location was correctly identified to perform MIP. The final clinical diagnosis of 7 normal SPECT/CT patients was secondary hyperparathyroidism on 6 months follow-up. We correctly identified the precise location of parathyroid adenomas or hyperplasia by (99m)Tc-sestamibi SPECT/CT which was helpful to perform MIP.

Aspiration coronary thrombectomy for acute myocardial infarction increases myocardial salvage

The aim of the study was to assess if aspiration thrombectomy in high risk patients with STEMI and angiographic evidence of thrombus may improve myocardial salvage. It is unclear if thrombus aspiration before percutaneous intervention (PCI) improves myocardial salvage. The trial was a prospective randomized study. The inclusion criteria were: first STEMI within 12 hr from symptoms onset, culprit lesion in left anterior descending or right coronary artery, culprit artery TIMI flow ≤ 2 and angiographic evidence of thrombus. The primary endpoint was myocardial salvage index (MSI) as assessed by (99m) Tc-sestamibi SPECT imaging. We randomized 137 patients (98 male, mean age 64.1 ± 12.5 years) either to aspiration thrombectomy followed by standard PCI with stent implantation (n = 67) or to standard primary PCI (n = 70). Index perfusion defect was similar in both study groups: 34.2% ± 13.1% in thrombectomy group versus 37.1% ± 12.0% in primary PCI group (P = 0.2). MSI was larger in aspiration thrombectomy group than in control patients [25.4% (IQR 13.5-44) vs. 18.5% (IQR 7.7-30.3) respectively, P = 0.02]. The final infarct size was smaller in patients treated with aspiration thrombectomy (23.1% ± 13.3% vs. 28.9% ± 10.2% in the control group, P = 0.002). Aspiration thrombectomy improves myocardial salvage in high risk STEMI patients with angiographic evidence of thrombus.

Effect of Proton Pump Inhibitors and H2 Antagonists on the Stomach Wall in 99mTc-Sestamibi Cardiac Imaging

On the basis of previously unpublished observations, we hypothesized that prolonged use of proton pump inhibitors (PPIs) causes an increase in (99m)Tc-sestamibi uptake in the stomach wall, manifested as curvilinear activity surrounding the photopenic fundus of the stomach cavity. We prospectively evaluated the frequency of stomach wall uptake in patients undergoing myocardial perfusion SPECT who were taking PPIs or H(2) antagonists. Patients (n = 138) who were scheduled for single-day rest/stress (99m)Tc-sestamibi SPECT were randomly selected. Poststress SPECT was performed 30 min after treadmill exercise or 45 min after dipyridamole infusion. The rest scan was obtained 45 min after tracer injection. All patients drank 473 mL of water 5-10 min after both the rest and the stress radiotracer injections. Patients were questioned regarding their use of PPIs and H(2) antagonists. The significant use of either was defined as more than 2 wk of continuous therapy before cardiac SPECT. Masked observers assessed poststress planar projection images in endless-loop cinematic format for the following 3 patterns: stomach cavity uptake, attributable to duodenogastric reflux of tracer; stomach wall uptake; and no stomach uptake. A 2-tailed chi(2) test with Yates correction was used to calculate statistically significant associations among variables. Only patients with observed patterns of stomach wall uptake (n = 30) and no stomach wall uptake (n = 91) were included. Patients with stomach cavity uptake (n = 17) were excluded because the assessment of the adjacent stomach wall uptake was not possible. Of the patients included (n = 121), 30 were men and 91 were women. Sixty-seven patients were older than 60 y; 26 patients were taking PPIs. Of the 95 patients not taking PPIs, 14 were taking H(2) antagonists. No patients were taking both medications. Stomach wall uptake was strongly associated with prolonged use of PPIs (chi(2) = 51.9, P < 0.0001). No statistically significant association was noted among age, sex, or use of H(2) antagonists (P = NS). Prolonged PPI therapy, but not H(2) antagonist therapy, contributes to a significant increase in stomach wall activity, potentially resulting in Compton scatter or ramp filter artifacts affecting the inferior wall of the left ventricle. Stomach wall activity, unlike the stomach cavity activity, cannot be prevented by the ingestion of water before imaging. Therefore, it is important to elicit a history of prolonged PPI use to better anticipate the possibility of increased stomach wall activity, which can confound the image quality and interpretation.

Preoperative 123I/99mTc-Sestamibi Subtraction SPECT and SPECT/CT in Primary Hyperparathyroidism

The trend toward focused surgical parathyroidectomy requires precise preoperative localization of parathyroid lesions in patients with hyperparathyroidism. The purpose of this study was to directly compare the diagnostic accuracy of (99m)Tc-sestamibi/(123)I subtraction SPECT with SPECT/CT for the localization of abnormal parathyroid glands in patients with primary hyperparathyroidism. A total of 61 consecutive surgical patients with primary hyperparathyroidism underwent both (123)I/(99m)Tc-sestamibi subtraction SPECT and SPECT/CT scans preoperatively, using a hybrid SPECT/CT instrument that combined a dual-detector SPECT camera with a 6-slice multidetector spiral CT scanner. Four hours after being given (123)I-sodium iodide orally, each patient received (99m)Tc-sestamibi intravenously, followed immediately by a simultaneous, dual-isotope SPECT scan of the neck and upper chest. Then, without moving the patient, we performed a non-contrast-enhanced CT scan of the same body region. Normalization and subtraction of the (123)I SPECT images from the (99m)Tc SPECT images were performed. The subtraction SPECT and the coregistered fused SPECT/CT studies were interpreted separately, with images scored on a 5-point scale. Surgical and histopathologic findings were used as the standard of comparison. Surgery was successful in 57 patients (solitary parathyroid adenoma in 48 patients, double parathyroid adenomas in 6 patients, and 10 hyperplastic parathyroid glands in 3 patients). The sensitivities of SPECT (50/70 = 71%) and SPECT/CT (49/70 = 70%) were similar (P = 0.779). The specificity of SPECT/CT (26/27 = 96%) was significantly greater than that of SPECT (13/27 = 48%; P = 0.006). The receiver-operating-characteristic area under the curve of SPECT/CT (0.833) was significantly greater than that of SPECT (0.632; P < 0.001). SPECT/CT is significantly more specific than dual-isotope subtraction SPECT for the preoperative identification of parathyroid lesions in patients with primary hyperparathyroidism.

Infarct size in primary angioplasty without on-site cardiac surgical backup versus transferal to a tertiary center: a single photon emission computed tomography study

Primary percutaneous coronary intervention (PCI) performed in large community hospitals without cardiac surgery back-up facilities (off-site) reduces door-to-balloon time compared with emergency transferal to tertiary interventional centers (on-site). The present study was performed to explore whether off-site PCI for acute myocardial infarction results in reduced infarct size. One hundred twenty-eight patients with acute ST-segment elevation myocardial infarction were randomly assigned to undergo primary PCI at the off-site center (n = 68) or to transferal to an on-site center (n = 60). Three days after PCI, (99m)Tc-sestamibi SPECT was performed to estimate infarct size. Off-site PCI significantly reduced door-to-balloon time compared with on-site PCI (94 +/- 54 versus 125 +/- 59 min, respectively, p < 0.01), although symptoms-to-treatment time was only insignificantly reduced (257 +/- 211 versus 286 +/- 146 min, respectively, p = 0.39). Infarct size was comparable between treatment centers (16 +/- 15 versus 14 +/- 12%, respectively p = 0.35). Multivariate analysis revealed that TIMI 0/1 flow grade at initial coronary angiography (OR 3.125, 95% CI 1.17-8.33, p = 0.023), anterior wall localization of the myocardial infarction (OR 3.44, 95% CI 1.38-8.55, p < 0.01), and development of pathological Q-waves (OR 5.07, 95% CI 2.10-12.25, p < 0.01) were independent predictors of an infarct size > 12%. Off-site PCI reduces door-to-balloon time compared with transferal to a remote on-site interventional center but does not reduce infarct size. Instead, pre-PCI TIMI 0/1 flow, anterior wall infarct localization, and development of Q-waves are more important predictors of infarct size.

Evaluation of Probable or Possible Dementia with Lewy Bodies Using 123I-IMP Brain Perfusion SPECT, 123I-MIBG, and 99mTc-MIBI Myocardial SPECT

We evaluated the diagnostic usefulness of combination studies with a statistical mapping method in N-isopropyl-p-(123)I-iodoamphetamine ((123)I-IMP) brain perfusion SPECT, cardiac sympathetic nerve function by (123)I-metaiodobenzylguanidine ((123)I-MIBG), and myocardial function by electrocardiographically gated (99m)Tc-sestamibi ((99m)Tc-MIBI) SPECT for patients with probable or possible dementia with Lewy bodies (DLB). Twelve patients with probable DLB (7 male, 5 female; mean age +/- SD, 72.3 +/- 5.63 y; range, 65-82 y) and 9 patients with possible DLB (3 male, 6 female; mean age +/- SD, 73.1 +/- 9.23 y; range, 59-88 y) were enrolled in this study. (123)I-IMP SPECT images were analyzed with 3-dimensional stereotactic surface projections (3D-SSP) and the severity of ischemia was classified objectively using quantitatively analytic and display software; stereotactic extraction estimation (SEE) methods were compared with a normal database. In addition, we evaluated (123)I-MIBG heart-to-mediastinum (H/M) uptake ratios. Moreover, we performed (99m)Tc-MIBI SPECT to evaluate myocardial perfusion and the left ventricular ejection fraction (LVEF) compared with a normal database. 3D-SSP images of group comparison with healthy control subjects showed significantly decreased perfusion in the parietotemporal, occipital cortex, posterior cingulated, and precuneus regions in the probable DLB group but no significant reduction in the possible DLB group. Mean H/M ratios in the probable DLB group were significantly lower than those of the possible DLB group and the control group, respectively. Ten of 12 patients (83.3%) with probable DLB and 1 of 9 patients (11.1%) with possible DLB showed severe reduction in the bilateral occipital lobe and also a low (123)I-MIBG uptake. One patient (8.3%) with probable DLB and 2 patients (22.2%) with possible DLB showed no bilateral occipital hypoperfusion but showed low (123)I-MIBG uptake. One patient (8.3%) with probable DLB and 6 patients (66.7%) with possible DLB showed no occipital hypoperfusion and normal (123)I-MIBG uptake. (99m)Tc-MIBI gated SPECT did not indicate any wall motion abnormality in any subjects. These results suggest that combined examination of cerebral blood flow with 3D-SSP and SEE analysis, and cardiac sympathetic nerve function with (123)I-MIBG, would be a useful supporting diagnostic method in patients with DLB-particularly, in possible DLB and when cerebral blood flow does not indicate occipital hypoperfusion.

Subtraction SPECT for Parathyroid Scintigraphy Based on Maximization of Mutual Information

Our objective was to investigate the feasibility of subtraction for SPECT images of (99m)Tc-MIBI double-phase parathyroid scintigraphy. Fourteen patients with hyperparathyroidism were enrolled in the present study. Histopathologically, excised tissue specimens showed hyperplasia in 11 patients and adenoma in 3 patients. Both ultrasonography and (99m)Tc-sestamibi (MIBI) SPECT images were obtained from all patients. As standard lines to ensure that patient positioning remained identical between the different phases, we used the cross-marker produced by a pair of laser pointers, the orbitomeatal line, and the vertical midline through the patient's nose. Data processing was performed with software that enables image registration by maximization of mutual information. The results of subtraction SPECT imaging were compared with those of ultrasonography. The registration of double-phase SPECT images was successful in all patients when the salivary glands were excluded from the image reconstruction region. The overall sensitivities of scintigraphy and ultrasonography were 90.9% (40/44) and 70.5% (31/44), respectively, with respective specificities of 83.3% (10/12) and 75.0% (9/12). Scintigraphy and ultrasonography showed accuracies of 92.8% (52/56) and 71.4% (40/56), respectively. The new technique used in the present study allowed the subtraction for SPECT images. The sensitivity of parathyroid lesion detection using this technique was superior to that of ultrasonography.

Role of 99mTc-sestamibi SPECT in accurate selection of primary hyperparathyroid patients for minimally invasive radio-guided surgery

Dear Sir, We read with interest the recent paper by Rubello et al. entitled “Role of Tc-sestamibi SPECT in accurate selection of primary hyperparathyroid patients for minimally invasive radio-guided surgery” [1]. Minimally invasive radio-guided surgery (MIRS) is widely employed for primary hyperparathyroidism caused by a solitary parathyroid adenoma. Since an intraoperative gamma probe is used, significant sestamibi uptake by the adenoma is important [2, 3]. Obviously, as the authors underline, radiation attenuation problems may cause underestimation of the sestamibi uptake by adenomas in an anterior planar image, resulting in doubt as to the appropriateness of MIRS in some cases. In this regard the authors report an interesting finding, namely that the parathyroid to background (P/B) ratio derived from SPECT correlates well with the intrasurgery P/B ratio; this means that using SPECT it is possible to predict the intraoperative measurement obtained with the gamma probe, thus allowing better patient selection for MIRS. However, we believe that this finding is not going to have a significant impact on the selection of patients for MIRS since only patients with a high probability of having a solitary adenoma are candidates for MIRS [4]. In our experience most of these patients demonstrate a P/B ratio significantly higher than the threshold, referred to by the authors, of 1.2 in the anterior planar image and thus do not require any quantitative confirmation. In the case of deeply located adenomas, despite the relatively reduced sestamibi intensity in the anterior planar image, they will still be well recognised as parathyroid lesions and any doubt about the appropriateness for MIRS in those cases can be dispelled just by knowing that the adenoma is located deeply. In this regard we visually estimate the depth and at the same time take into account the attenuation effect on sestamibi uptake from adenomas by using oblique planar imaging in all cases, rather than the time-consuming and rather complicated SPECT technique. Oblique planar imaging is easy to perform and very valuable even when the adenoma is behind the thyroid gland [5, 6]. In the presented study the ratio derived from SPECT was useful in only 1/22 patients although 7/22 adenomas were deeply located. The quantification might possibly be useful in estimating the appropriateness of the sestamibi uptake for MIRS in a few borderline cases. However, trying to include these patients will inevitably increase the probability of multiple gland disease since it is well known that frequently only the largest gland is visible in hyperplasia, especially in the early stages, when the size of the other glands remains below the sensitivity of the techniques used [7, 8]. The result will then be that more operations will be changed to bilateral exploration assuming that rapid PTH measurement is available. In this regard, SPECT, because of its slightly better sensitivity compared with planar imaging, would be most useful not in selecting more patients but rather in excluding some on the basis of the identification of more than one parathyroid lesion in cases of multi-gland disease. Nevertheless, ultrasound can contribute this important information even better than SPECT. In conclusion, we believe that in the selection of eligible patients for MIRS, quantification is not needed and that performance of SPECT exclusively for this purpose is not justified. Eur J Nucl Med Mol Imaging (2007) 34:607–608 DOI 10.1007/s00259-006-0332-y

Efficacy of milk versus water to reduce interfering infra-cardiac activity in 99mTc-sestamibi myocardial perfusion scintigraphy

Interference from infra-cardiac radionuclide activity prevents accurate interpretation of true myocardial perfusion. The study aim was to compare the efficacy of milk versus water in reducing infra-cardiac activity in myocardial perfusion scintigraphy. We prospectively randomized 198 patients undergoing stress-rest (99m)Tc-sestamibi SPECT with exercise or pharmacological stress to drink 300 ml of water or milk prior to imaging. A semi-quantitative grading of the relative intensity of infra-cardiac activity compared to the myocardial activity and a qualitative assessment of the effect on the overall interpretation was performed. For stress images, there was no infra-cardiac activity in 37.9%, less intense infra-cardiac activity in 40.8%, equal in 11.7% and greater than infra-cardiac activity in 9.7% with milk, compared with 20.0%, 49.5%, 20.0% and 10.5%, respectively, with water (P=0.038). For rest images, there was also less intense infra-cardiac activity with milk compared to water (P=0.014). However, no change in subsequent image interpretation was seen. Administration of milk resulted in a significant decrease in the intensity of infra-cardiac activity compared to water. However, this did not translate into an improvement in image interpretation.

Feasibility of in vivo dual-energy myocardial SPECT for monitoring the distribution of transplanted cells in relation to the infarction site

Cell therapy using bone marrow mesenchymal stem cells (BMSCs) shows promise in the treatment of myocardial infarction (MI) but accurate cell delivery within MI areas remains critical. In the present study, we tested the feasibility of in vivo pinhole SPECT imaging for monitoring the sites of intramyocardial implanted BMSCs in relation to targeted MI areas in rats. BMSCs were labelled with (111)In-oxine and injected within the fibrotic areas of 3-month-old MI in ten rats. Two days later, dual (111)In/(99m)Tc-sestamibi pinhole SPECT was recorded for localisation of (111)In-BMSCs on a 15-segment left ventricular (LV) division. Additional (99m)Tc-sestamibi pinhole SPECT had been performed 1 month earlier and on the day before transplantation. In vitro counting on histological sections was used to validate the pinhole SPECT determination of (111)In-BMSC activity within LV segments. The underperfused MI area (segments with <70% uptake) was stable between the (99m)Tc-sestamibi SPECT study recorded at 1 month (4.6+/-1.9 segments) and at 1 day (4.7+/-2.3 segments) before transplantation. (111)In-BMSCs were detected by dual-energy SPECT in 56 segments: 33 (59%) were underperfused MI segments but 23 (41%) were not (14 adjacent and nine remote segments). Finally, (111)In-labelled BMSCs were not detected in 14 out of the 47 (30%) underperfused MI segments. When BMSCs are injected within MI areas in rats, sites of early cell retention do not always match the targeted MI areas. The dual-energy pinhole SPECT technique may be used for monitoring the sites of early retention of implanted BMSCs and the data obtained may have critical importance when analysing the effects of cardiac cell therapy.

Minimally invasive (99m)Tc-sestamibi radioguided surgery of parathyroid adenomas.

In the last 10 to 15 years surgery of primary hyperparathyroidism (PHPT) moved from the wide bilateral neck exploration to various types of limited neck exploration ranging from unilateral neck surgery to minimally invasive approaches as the minimally invasive radioguided parathyroidectomy. In contrast with the bilateral neck exploration, an accurate preoperative localizing imaging, which is mainly based on (99m)TC-sestamibi scintigraphy, is mandatory when planning a concise parathyroidectomy. Following imaging criteria, only a fraction of PHPT patients accounting for approximately 60% to 70% of all PHPT patients can be eligible for a minimally invasive parathyroidectomy. Only PHPT patients with a high probability to be affected by a solitary parathyroid adenoma showing a high (99m)TC-sestamibi uptake and with a normal thyroid gland should be offer a minimally invasive radioguided parathyroidectomy. The (99m)TC-sestamibi SPECT technique and the double-tracer 123-iodine or (99m)TC-pertecnetate/(99m)TC-sestamibi scintigraphic technique are the most sensitive and accurate preoperative imaging modalities and their utilization is recommended when considering a minimally invasive radioguided parathyroidectomy. Two main intraoperative procedures for the minimally invasive radioguided surgery have been described: the single-day protocol and the different-day protocol. In the single-day protocol a 740 MBq dose of (99m)TC-sestamibi is injected to the patient, scintigraphic imaging is obtained by dual-phase technique and then the patient is operated on within approximately 3 hours from radio-tracer injection. In the different-day protocol, a double-tracer parathyroid scintigraphy is obtained some days before surgery with the aim of better planning the type and extension of intervention. The day of intervention, for the purpose of radioguided surgery only, a low 37 MBq dose of (99m)TC-sestamibi is injected to the patient in the operating theatre a few minutes before the start of intervention. The main advantages of minimally invasive radioguided parathyroidectomy over the traditional wide bilateral neck exploration can be resumed as follows: a shortening in the operating and recovery time, possibility of local anesthesia, possibility of ambulatory surgery or same-day discharge, less postsurgical hypocalcemia, less postsurgical pain, favourable cosmetic results, benefits from a cost-analysis point of view.

Combined 99mTc MDP bone SPECT and 99mTc sestamibi muscle SPECT for assessment of bone regrowth and free muscle flap viability in an electrical burn of scalp

A case of deep high energy electrical burn of the skull is presented. For assessment of bone regrowth and muscle flap viability after application of latissimus dorsi free flap, combined 99 m Tc MDP bone SPECT and 99 m Tc sestamibi muscle SPECT scintigraphy were used. Whereas 99 m Tc MDP bone SPECT showed absent uptake at the beginning, there was good uptake 3 months after flap application. 99 m Tc sestamibi SPECT revealed good uptake indicating normal perfusion of flap muscle tissue.

Quantification of myocardial blood flow velocity reserve with contrast echocardiography allows detection of milder stenoses compared to 99m Tc-sestamibi SPECT

Quantification of myocardial blood flow velocity reserve with contrast echocardiography allows detection of milder stenoses compared to 99m Tc-sestamibi SPECT

Myocardial Perfusion and Angiographic Findings in Patients with Paradoxical Sinus Deceleration during Dobutamine Technetium-99m Sestamibi-Gated SPECT Imaging

Aims: Dobutamine-gated SPECT imaging allows simultaneous perfusion and function assessment and is an alternative stress method for evaluating coronary artery disease in patients unable to perform treadmill exercise. In some patients, a paradoxical decrease in heart rate has been observed during high dose dobutamine infusion. The purpose of this study was to describe the paradoxical decrease in heart rate observed during dobutamine perfusion scintigraphy and determine its relation to inducible ischemia and angiographic coronary artery disease. Methods and Results: We studied 52 patients who underwent dobutamine-gated ^99mTc sestamibi SPECT imaging and coronary angiography within 30 days. Paradoxical deceleration was defined as a decrease in heart rate ≥5 beats/min lasting at least 3 min during dobutamine infusion. Perfusion was graded on a five-point scale (0 = normal; 4 = absent uptake) and wall motion on a four-point scale (0 = akinesia/dyskinesia; 3 = normal) using the 20-segment model. Significant coronary artery disease was defined as ≥50% narrowing of lumen diameter of a major epicardial artery. Paradoxical deceleration occurred in 10 patients (19%, 95% CI 8–30%). A decrease in systolic blood pressure [8 patients (80%), 95% CI 56–92%] with angina [5 patients (50%), 95% CI 23–71%] often accompanied the decrease in heart rate. All 10 patients with sinus deceleration had an inferior wall perfusion defect and 8 of them had a corresponding wall motion abnormality on gated images. Significant coronary artery disease was present in all 10 patients with sinus deceleration, with an increased incidence of right coronary artery stenosis (p = 0.007). Conclusions: Paradoxical deceleration observed during dobutamine perfusion scintigraphy is associated with inducible ischemia and angiographic coronary artery disease and the underlying mechanism for this phenomenon may be the activation of the Bezold-Jarisch reflex.

962-61 Late Redistribution T1-201/Stress Tc-99m Sestamibi Separate Acquisition Dual Isotope Myocardial Perfusion SPECT: A Feasibility Study

Rest TI201(TI)/stress Tc-sestamibi dual isotope SPECT (DIMPS) is an efficient myocardial perfusion protocol. Patients with rest defects, however, frequently require late TI redistribution imaging the next day. Thus, we recently implemented a modified DIMPS (M-DIMPS), with 3.5 mCi TI injected at rest the night before stress testing. On the day of stress testing, 12–18 hr redistribution TI (late TI) SPECT was performed prior to stress sestamibi study. To assess image quality of late TI, we prospectively studied 107 patients who underwent M-DIMPS. For purposes of comparison between conventional DIMPS and M-DIMPS, a subset (group A, n = 41) also had rest TI(25 sec/stop, 60 stops) the night before M-DIMPS. Late TI used 30 sec/stop. Prereconstruction processing used a 20 Butterworth filter (cut-off: 0.5/order 10 for rest TI, 0.35/order 10 for late TI). Comparisons were made for cardiac counts (counts/pixel) and quantitative heart to background ratio (H/B ratio). Image quality was assessed visually using a 5 point score (0 = unacceptable, 4 = excellent), based on the evaluation of image uniformity, defect clarity, left ventricular border definition and the apparent H/B ratio, Comparisons between rest TI and late TI in 41 group A patients yielded quantitative H/B ratio of 1.63 ± 0.39 and 1.49 ± 0,31 (p = 0.002), and total myocardial counts of 41.4 ± 18.1 and 29.3 ± 11.6 (p &lt; 0.001), respectively. Image quality agreement between rest TI and late TI was 90%, with 31 concordant good to excellent and 6 concordant fair studies. Analysis of the 107 late TI studies by patient weight revealed: &lt;150 Ibs (n = 31) 150–200 Ibs (n = 60) &gt;200 Ibs (n = 16) p cardiac counts 30.4 ± 9.6 28.9 ± 13.8 28.9 ± 7.5 ns H/B ratio 1.49 ± 0.24 1.46 ± 0.32 1.42 ± 0.25 ns quality = 3 or 4 90% 90% 63% &lt;0.05 * * &gt; 200lbs vs. the other two weight categories Although quantitatively different, late TI has acceptable count statistics and comparable visual image quality to rest TI, establishing the feasibility of late TI/stress Tc-sestamibi dual isotope SPECT in non-obese (&lt;200 Ibs) patients. The protocol allows for final reporting on the same day as stress testing, potentially decreasing the length of hospitalization.