Comparative Analysis of the Feasibility of Myocardial Blood Flow Index Versus CT-FFR in the Diagnosis of Suspected Coronary Artery Disease.

Background: Using fluid dynamic modeling, noninvasive fractional flow reserve (FFR) derived from coronary computed tomography angiography (CCTA) data provides better anatomic and functional information than CCTA, with a high diagnostic and discriminatory value for diagnosing hemodynamically significant lesions. Myocardial blood flow index (MBFI) based on CCTA is a physiological parameter that reflects myocardial ischemia. Thus, exploring the relationship between computed tomography derived fractional flow reserve (CT-FFR) and MBFI could be clinically significant. This study aimed to investigate the relationship between CT-FFR and MBFI and to analyze the feasibility of MBFI differing from CT-FFR in diagnosing suspected coronary artery disease (CAD). Methods: Data from 61 patients (35 males, mean age: 59.2 ± 10.02 years) with suspected CAD were retrospectively analyzed, including the imaging data of CCTA, CT-FFR, and data of invasive coronary angiography performed within one week after hospitalization. CT-FFR and MBFI were calculated, and the correlation between MBFI or CT-FFR and invasive coronary angiography (ICA) was evaluated. Using ICA (value ≥ 0.70) as the gold standard and determining the optimal cutoff value via a diagnostic test, the diagnostic performance of MBFI or CT-FFR was evaluated. Results: MBFI and CT-FFR were negatively correlated with ICA (r = -0.3670 and -0.4922, p = 0.0036 and 0.0001, respectively). Using ICA (value of ≥ 0.70) the gold standard, the optimal cutoff value was 0.115 for MBFI, and the area under the curve (AUC) was 0.833 (95% confidence interval [CI]: 0.716-0.916, Z = 5.357, p < 0.0001); using ICA (value of ≥ 0.70) the gold standard, the optimal cutoff value was 0.80 for CT-FFR, and the area under the curve (AUC) was 0.759 (95% CI: 0.632-0.859, Z = 3.665, p = 0.0002). No significant difference was observed between the AUCs of CT-FFR and MBFI (Z = 0.786, p = 0.4316). Conclusions: MBFI based on CCTA can be used to evaluate myocardial ischemia similar to CT-FFR in suspected CAD; however, it should be noted that CT-FFR is a functional index based on the anatomical stenosis of the coronary artery, whereas MBFI is a physiological index reflecting myocardial mass remodeling.

Diagnostic performance of coronary computed tomography angiography stenosis score for coronary stenosis.

BACKGROUND: Coronary computed tomography angiography stenosis score (CCTA-SS) is a proposed diagnosis score that considers the plaque characteristics, myocardial function, and the diameter reduction rate of the lesions. This study aimed to evaluate the diagnostic performance of the CCTA-SS in seeking coronary artery disease (CAD). METHODS: The 228 patients with suspected CAD who underwent CCTA and invasive coronary angiography (ICA) procedures were under examination. The diagnostic performance was evaluated with the receiver operating curve (ROC) for CCTA-SS in detecting CAD (defined as a diameter reduction of ≥ 50%) and severe CAD (defined as a diameter reduction of ≥ 70%). RESULTS: The area under ROC (AUC) of CCTA-SS was 0.909 (95% CI: 0.864-0.943), which was significantly higher than that of CCTA (AUC: 0.826; 95% CI: 0.771-0.873; P = 0.0352) in diagnosing of CAD with a threshold of 50%. The optimal cutoff point of CCTA-SS was 51% with a sensitivity of 90.66%, specificity of 95.65%, positive predictive value of 98.80%, negative predictive value of 72.13%, and accuracy of 91.67%, whereas the optimal cutoff point of CCTA was 55%, and the corresponding values were 87.36%, 93.48%, 98.15%, 65.15%, and 88.60%, respectively. With a threshold of 70%, the performance of CCTA-SS with an AUC of 0.927 (95% CI: 0.885-0.957) was significantly higher than that of CCTA with an AUC of 0.521 (95% CI: 0.454-0.587) (P < 0.0001). CONCLUSIONS: CCTA-SS significantly improved the diagnostic accuracy of coronary stenosis, including CAD and severe CAD, compared with CCTA.

Evaluation of 188Re-DTPA-deoxyglucose as a potential cancer radiopharmaceutical.

OBJECTIVE: We aimed to synthesize diethylenetriamine pentaacetic acid-deoxyglucose (DTPA-DG) radiolabeled with (188)Re and to evaluate its biologic characteristics using mammary tumor-bearing mice. MATERIALS AND METHODS: The biodistribution of the radiolabeled compound was determined by tissue counting at 3, 12, and 24 hours after injection in experimental animals. Scintigraphic examinations of nude mice bearing breast cancer (MCF-7 cells) were performed after (188)Re-DTPA-DG (18.5 MBq) was injected in the tail vein. For the tumor inhibitory portion of this work, tumor volumes were measured and recorded every 3 days until the 21st day after injection. RESULTS: The radiochemical purity of (188)Re-DTPA-DG was 95.0%. Based on biodistribution measurements, (188)Re-DTPA-DG was taken up at high levels by the tumor. The mean tumoral percent injected dosages per gram (% ID/g) were 1.98 +/- 0.29 (SD), 2.89 +/- 0.43, and 0.42 +/- 0.06 % ID/g at 3, 12, and 24 hours, respectively, after injection. In the (188)Re-DTPA-DG scintigraphic examinations, the tumors were clearly delineated on the images recorded 2, 4, 8, 12, and 24 hours after injection. In the tumor inhibitory evaluations, the tumor volume of the (188)Re-DTPA-DG-treated group increased more slowly than that of the control groups, which were treated with (188)Re-perrhenate or saline (p < 0.01). Rhenium-188-DTPA-DG showed excellent tumor targeting and tumor growth suppression properties on MCF-7 tumor cells. CONCLUSION: Rhenium-188-DTPA-DG may be a potential agent for the diagnosis and radiotherapy of tumors.

Review: Deoxyglucose compounds labeled with isotopes different from 18-fuoride: is there a future in clinical practice?

There are several radionuclide-labeled derivatives of deoxyglucose (DG) that have been developed including 2-fluro-deoxyglucose, ethylenedicysteine-deoxyglucose, diethylenetriaminepentaacetate-deoxyglucose, N-(2'-hydroxybenzyl)-2-amino-2-deoxy-D-glucose, and methyl D-glucoside that were synthesized and successfully labeled in high labeling fields. The former 4 were used for tumor imaging and methyl-D-glucoside for the diagnosis and the monitoring of the functional status of renal tubules. These derivatives are suitable for imaging examinations when labeled with either fluorine-18 (18F), technetium-99m (99mTc), carbon-11 (11C), or gallium-68 (68Ga). These compounds are suitable both for imaging and for therapy if labeled with rhenium-188 (188Re). In the area of molecular imaging of nuclear medicine, derivatives of radionuclide-labeled deoxyglucose will become an important tool for the diagnosis and carcinoma treatment in the clinic.

Study of apoptosis induced by 188Re-DTPA-DG in MCF-7 breast carcinoma and A549 pulmonary carcinoma cells.

OBJECTIVE: To evaluate apoptosis induced by rehenium-188-labeled diethylenetriamine pentaacetic acid-glucosamine (188Re-DTPA-DG) in MCF-7 breast carcinoma cells and A549 pulmonary carcinoma cells. METHODS: Through the use of flow cytometry (FCM) with CBA software to detect apoptosis, cells of both the MCF-7 and A549 cell lines were divided into groups exposed to 188Re-DTPA-DG, 188Re-perrhenate (188ReO4-), and saline, respectively. The first two groups were further divided into subgroups on the basis of their exposure to radioactivity at 37, 55.5, or 74 kBq/mL, with the saline-exposed group divided into three corresponding subgroups. Each subgroup was introduced into 5 replicate wells of a culture plate, and the morphology of the cells in each well was determined by flow cytometry at 6-hour intervals for 18 hours. In order to determine the affinity of 188Re-DTPA-DG for tumor tissue, the biodistribution of the radiolabeled agent was assessed in breast tumor-bearing nude mice. RESULTS: Change in morphology of the cell nucleus was more evident in the 188Re-DTPA-DG-treated than in the 188ReO4--treated group, and no change in nuclear morphology was seen in the saline-exposed group. The study data suggested that there was a greater ratio of apoptotic to nonapoptotic cells among the 188Re-DTPA-DG-treated than among the 188ReO4--treated or saline-exposed cells (p<0.01), and a greater change in cell-nuclear morphology in the 188Re-DTPA-DG-treated than in the 188ReO4--treated cells. Furthermore, 188Re-DTPA-DG had a more significant apoptosis-inducing effect on both MCF-7 and A549 cells than did 188ReO4-. The biodistribution study in tumor-bearing nude mice showed that the concentration of 188Re-DTPA-DG in tumor tissue was much higher than in normal tissue, that 188Re-DTPA-DG was rapidly cleared from the blood, and that the main route of its clearance was via the kidneys. CONCLUSIONS: 188Re-DTPA-DG has a significant apoptotic effect on carcinoma cells. 188Re-DTPA-DG is an effective radiopharmaceutical for intratumoral radiation therapy.