Accuracy of sentinel node biopsy in esophageal carcinoma: a systematic review and meta-analysis of the pertinent literature.

The use of sentinel node surgery for esophageal carcinoma is still under investigation. We evaluated the data available in the literature on this topic, and herein present the results in a systematic review format. PUBMED, SCOPUS, the ISI web of knowledge and the information from the annual meetings of the Japan Esophageal Society were searched using the search terms: "(esophagus OR esophageal) AND sentinel". The outcomes of interest were the detection rate and sensitivity. Overall, 18 studies were included. The pooled detection rate was 89.2% [82.6-93.5]. Patients with T1 and two tumors had a 17% higher detection rate compared to those with T3 and four tumors. The pooled sensitivity was 84% [78-88%]. The sensitivity was higher for adenocarcinoma compared to squamous cell carcinoma (SCC) (91 vs. 81%). In the SCC patients, there was a trend toward decreased sensitivity associated with an increasing tumor depth (T1:88%, T2:76%, T3:50%). Our analysis indicated that sentinel node biopsy is useful in adenocarcinoma patients. For SCC patients, including only cN0 patients (preferably T1 and 2) would increase the detection rate and sensitivity. Due to the limited number of high-quality studies, drawing any more definite conclusions is impossible. Large cohort studies with a standardized and consistent design will be needed in the future.

Diagnostic performance of fluorine 18 fluorodeoxyglucose positron emission tomography imaging for detection of primary lesion and staging of endometrial cancer patients: systematic review and meta-analysis of the literature.

OBJECTIVES: Fluorine 18 fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) imaging has been used for staging of endometrial cancer. In the current study, we systematically searched the available literature on the accuracy of (18)F-FDG PET imaging for staging of endometrial cancer. METHODS: PubMed, SCOPUS, ISI Web of Knowledge, Science Direct, and Springer were searched using "endometr* AND PET" as the search terms. All studies evaluating the accuracy of (18)F-FDG PET in the staging of endometrial carcinoma were included. Statistical pooling of diagnostic accuracy indices was done using random-effects model. Cochrane Q test and I(2) index were used for heterogeneity evaluation. RESULTS: Sixteen studies (807 patients in total) were included in the meta-analysis. Sensitivity and specificity for detection of the primary lesions were 81.8% (77.9%-85.3%) and 89.8% (79.2%-96.2%); for lymph node staging were 72.3% (63.8%-79.8%) and 92.9% (90.6%-94.8%); and for distant metastasis detection were 95.7% (85.5%-99.5%) and 95.4% (92.7%-97.3%). CONCLUSIONS: Because of low sensitivity, diagnostic utility of (18)F-FDG PET imaging is limited in primary tumor detection and lymph node staging of endometrial cancer patients. However, high specificities ensure high positive predictive values in these 2 indications. Diagnostic performance of (18)F-FDG PET imaging is much better in detection of distant metastases. Larger studies with better design are needed to draw any more definite conclusion.

Accuracy of hepatobiliary scintigraphy for differentiation of neonatal hepatitis from biliary atresia: systematic review and meta-analysis of the literature.

Hepatobiliary scintigraphy is an important diagnostic modality for work-up of neonatal cholestasis. Therefore, our objective was to evaluate the literature regarding the accuracy of hepatobiliary scintigraphy in differentiating biliary atresia from non-biliary atresia causes of cholestasis (collectively called neonatal hepatitis). Our search included Medline, SCOPUS and Google Scholar. Only studies using Tc-99 m-labeled immunodiacetic acid (IDA) derivatives were included. Overall, 81 studies were included in the meta-analysis. Pooled sensitivity and specificity were 98.7% (range 98.1-99.2%) and 70.4% (range 68.5-72.2%), respectively. Factors that increased specificity included the use of radiotracers with high hepatic extraction, administration of hepatic-inducing drugs (such as phenobarbital), use of a calculated dose/kg and administration of a booster dose in cases of non-excretion of the tracer in the bowel. SPECT imaging and duodenal fluid sampling also had high specificity; however, they need further validation because of the low number of studies. Semiquantitative imaging methods do not seem to have any incremental value. We conclude that hepatobiliary scintigraphy using IDA derivatives can be very useful for diagnostic work-up of neonatal cholestasis. To improve the specificity, several measures can be followed regarding type and dose of the radiotracer and imaging protocols. Non-imaging methods seem to be promising and warrant further validation.

Accuracy of sentinel lymph node biopsy for inguinal lymph node staging of penile squamous cell carcinoma: systematic review and meta-analysis of the literature.

PURPOSE: Sentinel lymph node biopsy is emerging as a promising method for inguinal lymph node staging of penile squamous cell carcinoma. In the current systematic review we evaluated the accuracy of sentinel lymph node biopsy for inguinal lymph node staging of penile squamous cell carcinoma and studied possible influential factors. MATERIALS AND METHODS: MEDLINE®, Scopus®, ISI®, Ovid SP®, Springer, ScienceDirect® and Google™ Scholar were searched by the key words "(penile OR penis) AND sentinel". No date or language limitation was imposed on the search and meeting abstracts were not excluded from analysis. A random effects model was used for statistical pooling. RESULTS: A total of 17 studies suitable for meta-analysis were detected. Three articles had 2 different subgroups of patients and each subgroup was considered as a separate study. Overall 18 studies (including the subgroups) were used for detection rate meta-analysis and 19 for sensitivity meta-analysis. The pooled detection rate was 88.3% (95% CI 81.9-92.6). Pooled detection rate of 90.1% (95% CI 83.6-94.1) was calculated for the studies using blue dye and radiotracer. The pooled sensitivity was 88% (95% CI 83-92). The highest pooled sensitivity (92% [95% CI 86-96]) was in the studies using radiotracer and blue dye, and recruiting only cN0 cases. CONCLUSIONS: Sentinel lymph node mapping in penile squamous cell carcinoma is a method with a high detection rate and sensitivity. Using radiotracer and blue dye for sentinel lymph node mapping and including only cN0 disease ensures the highest detection rate and sensitivity.

Unusual presentation of lumbar chordoma on bone scintigraphy in a young patient.

Chordoma is a rare bone cancer which arises from undifferentiated notochordal remnants in the axial skeleton. It generally has slow-growing and locally aggressive behavior. This tumor is usually diagnosed by CT and MRI modalities and the role of SPECT/CT is still debated. It shows reduced or normal uptake of radioisotope on bone scanning and increased tracer uptake is infrequently reported. Here we present a 33-year-old man with complaint of low back pain and numbness of his right leg. The whole body bone scan showed relatively uniform radiotracer activity throughout the skeleton. A focal increased uptake in the second lumbar vertebra was noted on SPECT/CT images. SPECT/CT also demonstrated multiple lytic lesions in lumbar vertebrae. The lesions were proven to be chordoma on biopsy. Lumbar chordoma could be one of the differential diagnoses for lytic lesions of the vertebrae which show absent or minimal tracer uptake on bone scintigraphy and SPECT/CT imaging. Our case was unusual as the patient was very young for chordoma diagnosis and bone scan showed increased uptake adjacent to the involved vertebral lesion detected by SPECT/CT.

Repeat injection following sentinel node nonvisualization on lymphoscintigraphy images can decrease axillary dissection rate in breast cancer patients.

AIM: Sentinel node biopsy is considered the standard of care in early-stage breast cancer patients. In the current study, we evaluated the effect of radiotracer reinjection in the case of sentinel node nonvisualization on preoperative lymphoscintigraphy. MATERIALS AND METHODS: Between March 2017 and March 2020, 1850 early-stage breast cancer patients were referred for sentinel node mapping. All patients received a single injected activity of Tc-99m Phytate intradermally in the periareolar area of the index lesion using an insulin syringe. Lymphoscintigraphy images of the patients were done 1-2 h postinjection. Between March 2017 and September 2017, sentinel node nonvisualization was reported to the surgeon, and for the rest of the study period, the patients received another injected activity of the radiotracer, and immediately, other lymphoscintigraphy images were taken (with the same parameters). RESULTS: A total of 255 patients entered our study. Fifty-five patients were in group I without any reinjection. The remainder of the patients were in group II. In 155 out of 200 patients of group II, a sentinel node could be visualized following reinjection of the radiotracer. The detection rate was 15 out of 45 and 15 out of 55 in group I and patients without sentinel node visualization even after reinjection, respectively. Axilla was involved in 5 out of 40 (12.5%) patients in group I with intraoperative sentinel node mapping failure. On the other hand, axilla was involved in 27 out of 30 (90%) group II patients with sentinel node nonvisualization. CONCLUSION: Reinjection of the tracer in cases of no sentinel node visualization in lymphoscintigraphy for breast cancer increases the detection rate of sentinel nodes, and therefore a high number of unnecessary axillary lymph node dissections can be avoided.

The effect of excisional biopsy on the accuracy of sentinel lymph node mapping in early stage breast cancer: comparison with core needle biopsy.

Despite the successful application of sentinel node mapping in breast cancer patients, its use in patients with a history of previous excisional biopsy of the breast tumors is a matter of controversy. In the present study we evaluated the accuracy of sentinel node biopsy in this group of patients and compared the results with those in whom the diagnosis of breast cancer was established by core needle biopsy. Eighty patients with early stage breast carcinoma were included into our study. Forty patients had a history of previous excisional biopsy and the remainder 40 had undergone core needle biopsy. Intradermal injections of 99mTc-antimony sulfide colloid as well as patent blue were both used for sentinel node mapping. Sentinel nodes were harvested during surgery with the aid of surgical gamma probe. All patients underwent standard axillary lymph node dissection subsequently. Detection rate was 97.5 per cent for both groups of the study. Number of detected sentinel node during surgery was not significantly different between groups. False negative rate was 0 per cent for both groups of the study. In conclusion sentinel node biopsy is reliable in patients with previous history of excisional biopsy of the breast tumors and has a low false negative rate.

Systemic absorption of Tc-99m-pertechnetate during dacryoscintigraphy: a note of caution.

We report a 37-year-old patient with the history of bilateral epiphora, who was referred to our department for dacryoscintigraphy imaging. The patient had bilateral obstruction of the lacrimal apparatus at the sac-duct level on the scintigraphy images. Delayed imaging showed Tc-99m pertechnetate uptake in the thyroid due to systemic absorption of the tracer from the conjunctiva. We recommend using tracers with large particle size and lower possibility of mucosal absorption for dacryoscintigraphy in order to decrease unnecessary thyroid radiation.

The efficacy of Tc-99m sestamibi for sentinel node mapping in breast carcinomas: comparison with Tc-99m antimony sulphide colloid.

BACKGROUND: To study the value of periareolar intra-dermal injection of Tc-99m sestamibi (MIBI) for sentinel node mapping in breast carcinoma. MATERIAL AND METHODS: Fifty patients with early-stage breast cancer were included in our study. 17.5 MBq Tc-99m-MIBI was injected intradermally to 25 patients and the remainders were injected with the same dose of Tc-99m-antimony sulphide colloid. Anterior and lateral static images were taken at 2 minutes. If sentinel lymph node was not detected, delayed imaging by up to 180 minutes was carried out. The patients were operated on 2-4 hours post-injection. Sentinel lymph node biopsy was performed by the aid of gamma probe and blue dye during surgery. RESULTS: In the Tc-99m-MIBI group, 23 patients had lymph nodes on scintigraphy images, and sentinel nodes were detected during surgery in all 23 patients. In the Tc-99m-antimony sulphide colloid group, 24 patients had lymph nodes on scintigraphy images, and sentinel nodes were identified during surgery in 24 patients. CONCLUSIONS: We concluded that 99mTc-MIBI is a suitable radiopharmaceutical for sentinel node detection.

The additive value of transient left ventricular dilation using two-day dipyridamole 99mTc-MIBI SPET for screening coronary artery disease in patients with otherwise normal myocardial perfusion: a comparison between diabetic and non-diabetic cases.

The prognostic value of transient ischemic dilation (TID) has been previously confirmed; however, its clinical significance for screening coronary artery disease (CAD) with balanced ischemia, as a cause of false negative myocardial perfusion imaging (MPI), is unclear. The goal of this study was to determine the additive diagnostic value of TID ratio for screening CAD in separate subgroups of diabetic and non-diabetics with normal perfusion. Eighty six patients with intermediate probability of CAD who had TID more than one in the presence of otherwise normal MPI using two-day technetium-99m methoxy isobutyl isonitrile ((99m)Tc-MIBI) single photon emission tomography (SPET) and dipyridamole stress (summed stress score<3 and left ventricular cavity<90 mL) were included in a prospective cohort study comprising two subgroups of diabetic and non- diabetic patients. An inclusive work-up with multiple noninvasive tests was performed for all patients from whom 38 cases subsequently underwent coronary angiography and 48 cases were categorized in the group with a very low likelihood (<5%) of CAD on the basis of clinical and paraclinical data over a minimum of 18 months follow up. The TID ratio was calculated using automated software. Gensini score (GS) as an indicator of severity/extent of stenosis and coronary artery index (CAI) as the number of arteries with more than 50% narrowing were calculated based on angiographic findings. Our results showed that only in diabetic patients with three-vessel disease, TID ratio (1.47 ± 0.23) differs significantly from the other groups of CAD. In diabetic patients subgroup, TID ratio correlated strongly with GS (r=0.957, P<0.0001) and CAI (r=0.659, P=0.001), while such correlations were not seen in the non-diabetic patients. On the basis of receiver operating characteristic curve analysis for screening CAD in diabetic patients with normal myocardial perfusion, 100% sensitivity and 77.8% normalcy rate were achieved when TID more than 1.16 was regarded as abnormal. No distinct cut-off value for abnormal TID was obtained in the non-diabetic patients. In conclusion, TID in diabetic patients without regional myocardial perfusion abnormality is an important sign of CAD especially when TID ratio exceeds 1.16. The higher TID ratio in these cases may predict increasing possibility of severe and extensive CAD. The value of TID in non-diabetic patients with otherwise normal MPI is not clearly determined.

99mTc sestamibi imaging - can it be a useful substitute for hepatobiliary scintigraphy in infantile jaundice?

AIM: Hepatobiliary scintigraphy is an integral part in the diagnostic work-up of the neonatal cholestasis syndrome. However, less than optimal specificity is its major disadvantage. Differentiation between biliary atresia and neonatal hepatitis is nearly impossible in some cases with poor hepatocellular function. 99mTc sestamibi (MIBI) is a cationic lipophilic agent which is a substrate of P-glycoprotein. This glycoprotein is normally expressed in biliary canalicular surfaces of hepatocytes. This property provides a hepatic excretory mechanism which is different from bilirubin excretion. In this study we evaluated the value of 99mTc MIBI in differential diagnosis of neonatal cholestasis. PATIENTS, METHODS: 20 infants with a mean age of 2.41 months (range, 0.1-5 months) were included in the study. Ten infants turned out to have extrahepatic biliary atresia and the other ten had neonatal hepatitis. Hepatobiliary (with 99mTc BrIDA) and 99mTc MIBI scintigraphy were performed for all the patients. RESULTS: 99mTc MIBI scintigraphy has shown bowel activity in all patients, including the patients with biliary atresia. Hepatobiliary scintigraphy revealed bowel activity only in five patients with neonatal hepatitis. CONCLUSION: Bowel visualization with 99mTc MIBI may be seen in patients with biliary atresia and 99mTc MIBI has limited value in differential diagnosis of neonatal cholestasis.

Review of the linogram and sinogram: an easy way to detect off-peak artifacts in myocardial perfusion SPECT.

The correct energy window setting and a stable photopeak position are crucial for good data acquisition. We report a patient whose myocardial perfusion SPECT images showed mildly irregular radiotracer uptake when the patient was prone but not when the patient was supine. Review of the sinogram showed clear interruptions in the sinusoidal shape of the raw data when the patient was prone. Detailed technical evaluation revealed that the artifact was caused by an unstable photopeak position due to malfunction of a power supply board of the gamma-camera. This case emphasizes the importance of reviewing the sinogram display and raw data to assess the integrity of data acquisition and to reveal any potential technical problems such as a spontaneous shift of the photopeak.

How to apply the evidence-based medicine concept to nuclear medicine diagnostic studies -- a review.

Evidence-based medicine (EBM) is defined as using the best available evidence for managing patients in daily healthcare practice. Although this approach has been applied successfully in many medical fields, it has not been addressed fully in the radiological discipline in general and nuclear medicine in particular. In this review, the concept of EBM has been introduced briefly and four steps of EBM practice have been explained. Asking answerable questions and finding the best evidence that constitutes the first two parts of EBM practice are explained in brief. The next two steps (appraising the available evidence and applying the best evidence) are explained in more detail. Since the bulk of nuclear medicine studies are of a diagnostic nature and most of the daily practice of a nuclear medicine specialist is involved in diagnosis, we have focused on the diagnosis studies. Systematic reviews are also explained to some extent. Appraisals of other kinds of study, such as interventional or prognosis studies, are not included in this review.

Comparison of pre-operative lymphoscintigraphy with inter-operative gamma probe and dye technique regarding the number of detected sentinel lymph nodes.

Sentinel lymph node (SLN) identification by lymphoscintigraphy (LS) and biopsy are the standard method for axillary lymph node staging in low stage breast cancer patients. Many previous studies did not compare the number of SLN on LS with SLN detected during surgery. We aimed to study the accuracy of pre-operative LS for the prediction of the number of SLN detected by surgical gamma probe and the dye technique during surgery. Sixty patients were included in our study. SLN biopsy was performed using the combined radioactive and blue dye methods. Patients without previous excisional biopsy of the tumor (45 patients) received periareolar intra-dermal injections of 17.5MBq/0.2mL technetium-99m-antimony sulfide colloid ((99m)Tc ASC). The remainder of the patients, with the history of excisional biopsy of the tumor (15 patients); received two intra-dermal injections of 17.5MBq/0.2mL (99m)Tc-ASC in both ends of the surgical incision. All injections were done 2-4 h before surgery and gentle massage was applied to the injection site. Results showed that the number of SLN was correctly detected by LS in 58 patients. Eighty SLN were totally detected during surgery. All these SLN were radioactive and could be identified by surgical gamma probe. No SLN was detected only by the blue dye. Of the 80 detected SLN, 60 (75%) were both radioactive and colored. Pre-operative LS correctly predicted the number of harvested SLN during surgery in 77.5% of the patients. Only 78.7% (63/80) of the total harvested SLN were detected by pre-operative LS. We conclude that pre- operative LS identifies 78.7% and the blue dye technique can identify 75% of the SLN found by the gamma probe during surgery. The pre-operative LS technique can correctly identify the number of SLN in 77.5% of the patients.

18FDG PET/CT in pulmonary arcinosarcoma and rain etastasis.

Carcinosarcoma is a rare type of cancer that is composed of a mixture of sarcomatous and carcinomatous elements. Pulmonary carcinosarcoma has a 25% five-year survival rate with a prognosis poorer than other non-small cell lung carcinomas. Herein, we report a case of pulmonary carcinosarcoma and its 18F-FDG PET/CT findings. A 61-year-old male patient presented with brain symptoms, including headache, nausea, right hemiplegia, and few attacks of seizures. He underwent brain computed tomography (CT) scan showing a brain lesion in the left parietal lobe. The patient underwent excisional biopsy, and brain lesion was removed. The results of tissue sampling were indicative of carcinosarcoma. Based on anatomical imaging and evidence of pulmonary lesion, the patient underwent 18FDG PET/CT that revealed a heterogeneous mass on the upper lobe of the left lung. An intense FDG uptake was observed along the rim of the mass; however, no FDG uptake was observed in the center of the mass. There were multiple mediastinal lymph nodes with a high FDG uptake. Pulmonary carcinosarcoma was confirmed by tissue sampling.

Sentinel ode apping in on-small ell ung ancer sing an ntraoperative adiotracer echnique.

OBJECTIVES: Lymph node metastases are the most significant prognostic factor in localized non-small cell lung cancer (NSCLC). Identification of the first nodal drainage site (sentinel node) may improve detection of metastatic nodes. Extended surgeries, such as lobectomy or pneumonectomy with lymph node dissection, are among the therapeutic options of higher acceptability. Sentinel node biopsy can be an alternative approach to less invasive surgeries. The current study was conducted to evaluate the accuracy of sentinel node mapping in patients with NSCLC using an intraoperative radiotracer techniques. METHODS: This prospective study was conducted on 21 patients with biopsy-proven NSCLC who were candidates for sentinel node mapping during 2012-2014. All patients underwent thoracoabdominal computed tomography, based on which they had no lymph node involvement. Immediately after thoracotomy and before mobilizing the tumor, peritumoral injection of 2mCi/0.4 mL Tc-99m- phytate was performed in 4 corners of tumor. After mobilization of the tumoral tissues, the sentinel nodes were searched for in the hillar and mediastinal areas using hand-held gamma probe . Any lymph node with in vivo count twice the background was considered as sentinel node and removed and sent for frozen section evaluation. All dissected nodes were evaluated by step sectioning and hematoxylin and eosin staining (H&E).The recorded data included age, gender, kind of pathology, site of lesion, number of dissected sentinel nodes, number of sentinel nodes, and site of sentinel nodes. Data analysis was performed in SPSS software (version 22). RESULTS: The mean age of the patients was 58.52±11.46 years with a male to female ratio of 15/6. The left lower lobe was the most commonly affected site (30.09%). Squamous cell carcinoma and adenocarcinoma were detected in 11 and 10 subjects, respectively. A total of 120 lymph nodes were harvested with the mean number of 5.71±2.9 lymph nodes per patient. At least one sentinel node was identified in each patient, resulting in a detection rate of 95.2%. The mean number of sentinel nodes per patient was 3.61±2. Frozen section results showed 100% concordance with the results of hematoxylin and eosin staining. CONCLUSION: Based on the findings, sentinel node mapping can be considered feasible and accurate for lymph node staging and NSCLC treatment.

Application of technetium-99m-sestamibi in differentiation of active from inactive pulmonary tuberculosis using a single photon emission computed tomography method.

OBJECTIVE: We studied the usefulness of 99mTc-methoxyisobutylisonitrile (MIBI) scintigraphy for differentiation between active and inactive pulmonary tuberculosis. METHODS: Thirty-six patients (aged 27-82 years, 16 males and 20 females) were included in our study. Each patient was injected with 740 MBq (20 mCi) 99mTc-MIBI and both planar and single photon emission computed tomography (SPECT) imaging were performed 15 and 60 min after injection. Twenty-four patients had active pulmonary tuberculosis (proven by sputum culture), and the remainder 12 had negative sputum culture. Semiquantitative as well as visual assessments were done on all sets of images. RESULTS: All of the 12 patients in the control group had negative scintigraphy on both planar and SPECT images. Twenty patients with active pulmonary tuberculosis had positive 99mTc-MIBI scintigraphy on planar images (sensitivity of 87.5%). SPECT images were positive in 23 patients with active pulmonary tuberculosis (sensitivity of 95.8%). Both semiquantitative and visual assessment of planar and SPECT images showed statistically significant differences between active and inactive pulmonary tuberculosis patients (P<0.001). Comparison of 15 and 60 min image sets did not show any statistically significant difference (P=0.956 and 0.457 for planar and SPECT images, respectively). CONCLUSION: 99mTc-MIBI has significant uptake in the active tuberculosis lesions and can be used to differentiate between active and inactive tuberculosis. The SPECT method is especially useful because of its higher sensitivity.

Age-related changes in skull uptake on bone scintigraphy: a quantitative study.

BACKGROUND: "Hot skull", or diffuse increased activity of bone seeking radiotracers, is frequently seen in the bone scans of some patients, especially elderly women. This finding has been attributed to enhanced bone metabolism in old age. MATERIAL AND METHODS: We semi-quantitatively studied 342 normal bone scans (161 male and 181 female within the age range 12 to 82 years). We divided the patients into 7 age groups: 10-19, 20-29, 30-39, 40-49, 50-59, 60-69, and 70 and above. The geometric means of the anterior and posterior background corrected skull and mid-femoral ROI values were used for calculation of the skull to femoral ratio (SFR). RESULTS: The skull to femoral ratio was significantly higher in female patients in the age groups 30-39 and above. In females, the five upper age groups (30-39, 40-49, 50-59, 60-69, and 70 and above) had significantly higher SFR than the lower age groups. In males, the two upper age groups (60-69, 70 and above) had significantly higher SFR than the lower age groups. The findings in males were not concordant with the previous studies addressing this issue, which could be explained by different bone mineral density in the Iranian population. CONCLUSION: Our data showed that "hot skull" is not necessarily an abnormal finding, especially in elderly women. We suggest that every nuclear medicine department uses its own normal values and reference samples for quantitative evaluation, due to ethnic or socio-economical variations.

Assessment of transient left ventricular dilation ratio via 2-day dipyridamole Tc-99m sestamibi nongated myocardial perfusion imaging.

BACKGROUND: The definition of an abnormal transient ischemic dilation (TID) ratio may be different according to stress type, type of isotope, and imaging protocols. The aim of this study was to derive the normal threshold and assessment of the TID ratio via 2-day dipyridamole stress/rest technetium 99m sestamibi myocardial perfusion single photon emission computed tomography (MPS). METHODS AND RESULTS: We performed 2-day dipyridamole stress/rest Tc-99m sestamibi MPS in 665 patients. The TID ratio was calculated automatically with the Emory Cardiac Toolbox. The upper limit of normal (1.19) for the TID ratio was derived from 131 patients with a low (<5%) likelihood of coronary artery disease as mean + 2 SDs. Patients with complete or partial reversible defects or multivessel-type or left anterior descending artery (LAD) territory perfusion abnormalities had higher TID ratios than the other patients. These patients had a higher frequency of an abnormal TID ratio (>1.19) as well. Binary logistic regression analysis showed that ischemia and LAD territory perfusion abnormality were independent predictors of an abnormal TID ratio. CONCLUSION: The threshold for an abnormal TID ratio via 2-day post-dipyridamole stress/rest Tc-99m sestamibi MPS was greater than 1.19. By use of this protocol, TID is not uncommon and it is related to a greater amount of ischemic burden as well as multivessel-type or LAD territory perfusion abnormality.

Comparison of two software in gated myocardial perfusion single photon emission tomography, for the measurement of left ventricular volumes and ejection fraction, in patients with and without perfusion defects.

Emory cardiac toolbox (ECTb) and quantitative gated single photon emission tomography - SPET (QGS) software are the two most often used techniques for automatic calculation of left ventricular volumes (LVV) and ejection fraction (LVEF). Few studies have shown that these software are not interchangeable, however the effect of perfusion defects on performance of these software has not been widely studied. The aim of this study was to compare the performance of QGS and ECTb for the calculation of LVEF, end-systolic volume (ESV) and end-diastolic volume (EDV) in patients with normal and abnormal myocardial perfusion. One hundred and forty-four consecutive patients with suspected coronary artery disease underwent a two-day protocol with dipyridamole stress/rest gated technetium-99m-methoxy isobutyl isonitrile ((99m)Tc-sestamibi) myocardial perfusion (GSPET) (8 gates/cardiac cycles). Rest GSPET scintiscan findings were analyzed using QGS and ECTb. Correlation between the results of QGS and ECTb was greater than 90%. In patients with no perfusion defects, EDV and LVEF using ECTb, were significantly higher than using QGS (P<0.001), whereas no significant difference was noticed in ESV (P=0.741). In patients with perfusion defects, also ECTb yielded significantly higher values for EDV, ESV and LVEF than QGS (P<0.001). In tomograms of patients with perfusion defects, mean differences of EDV and ESV between the two software, were significantly higher than in tomograms of patients without defects (P<0.001), while for LVEF this difference was not significant (P= 0.093). Patients were classified into three subgroups based on the summed rest score (SRS); G1: patients with SRS < or = 3 (n=109), G2: patients with 4 < or = SRS < or = 8 (n=13) and G3: patients with SRS > or = 9 (n=22). One-way ANOVA showed that the mean differences of EDV and ESV values between ECTb and QGS between the subgroups were significant (P<0.001 for both parameters), while no significant difference was noticed between the subgroups, as for the mean difference of LVEF, calculated by the two software (P=0.07). By increasing SRS, the EDV and ESV values were overestimated to a higher level by the ECTb as compared to the QGS software. Linear regression analysis showed that the difference in LVV values, between the two software increased, when SRS also increased (P<0.001). In conclusion, correlation between QGS and ECTb, software was very good both in patients with and without perfusion defects. In patients with perfusion defects, calculated LVEF, ESV and EDV values are higher using ECTb compared to the QGS software. However, the more extensive the perfusion defect was, the greater the difference of LVV between these two software. For the follow up of patients, we suggest the use of a single software either QGS or ECTb, for serial measurements of LV function.