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Background: After the diagnosis Non-Small-Cell Lung Carcinoma (NSCLC) has been established, consideration must turn toward the stage of disease, because this will impact directly on management and prognosis. Staging is used to predict survival and to guide the patient toward the most appropriate treatment regimen or clinical trial. Distinguishing malignant involvement of the mediastinal lymph nodes (N2 or N3) from the hilar lymph nodes, or no lymph nodes (N0 or N1) is critical, because malignant involvement of N2 or N3 lymph nodes usually indicates non-surgically resectable disease. The purpose of this study was to examine and compare CT versus integrated F18-FDG PET/low dose CT (FDG PET/CT) for mediastinal staging in NSCLC, and the desire was to safely distinguish between malignant and benign lesions without the need for invasive procedures. All results were controlled for reproducibility., Methods: 114 participants with NSCLC were included in a prospective cohort study. Blinded CT and FDG PET/CT images were reviewed. The participants' mediastinums were staged based on lymph node sizes (CT), or on FDG uptake (FDG PET/CT). Reference standard was tissue sampling., Results: We found that there was no measureable difference between CT and FDG PET/CT mediastinal staging results; overall two-thirds of the participants in the study were correctly staged, and almost one-third of the participants were falsely staged., Conclusion: Neither CT nor FDG PET/CT could obviate the need for further invasive staging prior to thoracotomy in patients with NSCLC; for that purpose, the results of both modalities were too meagre. Therefore, these patients still depend on invasive staging methods. In our study, invasive staging was accomplished by mediastinoscopy. However, today this is increasingly replaced by EBUS or EUS.

Pulmonary nodules are of high clinical importance, given they may prove to be an early manifestation of lung cancer. Pulmonary nodules are small, focal, radiographic opacities that may be solitary or multiple. A solitary pulmonary nodule is a single, small (<-30 mm in diameter) opacity. Larger opacities are called masses and are often malignant. As imaging techniques improve and more nodules are detected, the optimal management of pulmonary nodules remains unclear. However, the question of malignancy of any given nodule remains the same. A standard contrast-enhanced computed tomography (CT) scan is often the first examination, followed by a number of other examinations. The purpose of this study was to examine the clinical feasibility of CT versus integrated [18F]fluorodeoxyglucose-positron emission tomography (PET)/low-dose CT scan in patients with suspected lung cancer and pulmonary lesions on CT. All results were controlled for reproducibility. We found that when used early in the work-up of the lesions, CT raised the prevalence of lung cancer in the population to the point where further diagnostic imaging examination could be considered futile. We also found that the overall diagnostic accuracy, as well as the classification probabilities and predictive values of the two modalities were not significantly different; the reproducibility of these results was substantial.

Background: Primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction results in TIMI 3 flow in most patients. However, despite TIMI 3 flow, some patients do not achieve adequate tissue perfusion and have large infarctions. Techniques that, in the acute setting, could identify these patients at increased risk would potentially enable specific interventions to enhance perfusion. The object of the present study was to test whether corrected TIMI frame count (CTFC), myocardial blush grade (MBG), ST-segment resolution, and myocardial perfusion imaging (MPI) can identify those patients who, despite successful treatment with primary PCI for ST-elevation myocardial infarction, are at risk for large infarcts., Methods: In 61 patients with TIMI 3 flow after primary PCI, CTFC, MBG, ST-segment resolution, and quantitative MPI by technetium Tc 99m sestamibi single photon emission computed tomography were estimated immediately after primary PCI. Infarct size was assessed by peak lactate dehydrogenase (LDH) and by MPI after 3 months., Results: Infarct size by MPI was 12% (4, 23), and peak LDH was 1410 U/L (870, 2220); these measures correlated (rho = 0.80, P < .001). The acute perfusion defect predicted infarct size using either method (MPI rho = 0.88, P < .001; LDH rho = 0.77, P < .001); ST-segment residual correlated weakly to infarct size, whereas CTFC and MBG did not. In multivariate analysis, the acute perfusion defect was the only significant predictor of infarct size., Conclusion: Myocardial perfusion imaging performed immediately after successful PCI can identify patients at increased risk for large infarcts due to impaired tissue perfusion. Acute MPI might serve as a tool for early identification of patients, who, despite epicardial TIMI 3 flow, have inadequate tissue level perfusion.

Objective: To compare renal clearance of technetium Tc 99m pentetate with plasma clearance by use of a glomerular filtration rate technique in pigs from 3 to 24 weeks of age., Animals: 24 female pigs., Procedure: At the time of investigation, 5 pigs were 3 weeks old, 6 pigs were 6 weeks old, 8 pigs were 12 weeks old, and 5 pigs were 24 weeks old. Plasma clearance of technetium Tc 99m pentetate was measured by the use of a single injection technique followed by collection of multiple blood samples until 5 hours after the injection. Simultaneously, urine was collected through a urinary catheter, and the renal clearance of technetiumTc 99m pentetate was calculated. Plasma clearance of technetium Tc 99m pentetate was correlated with the renal clearance (r = 0.95). Plasma clearance was higher than renal clearance at all ages (mean, 5.8%), indicating extrarenal clearance of technetium Tc 99m pentetate or methodologic errors. Volume of distribution increased with increasing age but decreased as a fraction of body weight., Conclusions: Plasma clearance of technetium Tc 99m pentetate estimates renal clearance with acceptable precision when using single injection technique and multiple biood samples in pigs from 3 to 24 weeks of age.

99Tcm-Diethylenetriaminepentaacetic acid (99Tcm-DTPA) has been postulated to be more bound to plasma proteins than are other radiopharmaceuticals used for measurement of glomerular filtration rate (GFR). The results of protein binding experiments are, however, highly related to methodology. The aim of the present study was to compare the protein binding of the 99Tcm-DTPA preparation we use in our daily routine with that of the other five 99Tcm-DTPA preparations available and with other GFR tracers by using the same ultrafiltration method. Protein binding was studied in vitro after incubation in donor plasma and in vivo after single injection in patients. A correction for the uneven distribution of ultrafiltrable ions ('Donnan effect') was included. Quality control of six 99Tcm-DTPA preparations performed with thin layer chromatography showed a high labelling efficiency (96.2-99.9%). The in vitro protein binding ranged from 9.25% to 11.12%. The in vitro protein binding of 99Tcm-DTPA was not significantly different from that of 51Cr-ethylenediaminetetraacetic acid (51Cr-EDTA) and 125I-iothalamate (10.99% vs 12.15%, and 9.55%). There was no difference in the in vivo protein binding of 99Tcm-DTPA 5 and 40 min after injection (13.28% vs 12.58%), and there was no difference in the protein binding of 99Tcm-DTPA and 51Cr-EDTA (12.93% vs 12.54%). In conclusion, in vitro and in vivo protein binding of 99Tcm-DTPA was 10-13%. The protein binding was not different from the binding of 51Cr-EDTA and 125I-iothalamate.

Objectives: The present study evaluated the impact of recruitable collaterals on regional myocardial perfusion measured by 99mtechnetium (Tc)-sestamibi single-photon emission computerized tomography (SPECT) during temporary coronary occlusion and related these estimates to the coronary wedge pressure and electrocardiographic (ECG) ST-segment changes., Background: Clinical variables (angina and ECG changes) and intracoronary flow and pressure recordings have indicated a protective role of recruitable collaterals on myocardial perfusion during percutaneous transluminal coronary angioplasty (PTCA)., Methods: Thirty patients (mean age 55 years, SD 9; 20 men) with stable angina pectoris and proximal nonocluding single-vessel left anterior descending coronary artery (LAD)-stenosis scheduled for PTCA were included. Visualization of recruitable collaterals by ipsilateral and contralateral contrast injection, registration of coronary wedge pressure and injection of 99mTc-sestamibi during 90-s LAD occlusions were undertaken. A rest perfusion study was performed within four days before PTCA. As an estimate of the severity of regional hypoperfusion during occlusion, an occlusion/rest count ratio was calculated (mean defect pixel count during occlusion divided by mean pixel count in identical regions at rest)., Results: The scintigraphic occlusion/rest count ratio was higher in patients with recruitable collaterals (n = 16), 67 +/- 11%, compared to patients without collaterals (n = 14), 60 +/- 6% (p < 0.05). The occlusion/rest count ratio correlated with the coronary wedge pressure (R2 = 0.34; p < 0.001). The occlusion/rest count ratio was lower, 61 +/- 6%, in patients with ST-segment elevation (n = 23) versus 74 +/- 9% in patients without ST-segment elevation (n = 7) (p < 0.0001)., Conclusions: Using 99mTc-sestamibi SPECT imaging during brief episodes of coronary occlusion, the severity of regional myocardial hypoperfusion was reduced by the presence of recruitable collaterals in a selected patient population with proximal LAD stenoses. Our results demonstrate a protective effect of recruitable collaterals on myocardial perfusion during temporary coronary occlusion.

99mTc-L,L-ethylenedicysteine (99mTc-EC) has been proposed as a 99mTc-labelled alternative to radio-iodinated ortho-iodohippurate (OIH) for renal imaging and evaluation of renal function. The kinetics of this new renal function agent were studied by a single-injection plasma clearance technique in pigs. 99mTc-EC, 131I-OIH and 125I-iothalamate were injected and the plasma concentration of the three tracers was followed for 240 min. Renal, hepatic and total plasma clearance were calculated. There was no difference between the renal plasma clearance of 99mTc-EC and 131I-OIH (175 +/- 9 versus 178 +/- 8 ml min-1, P = 0.43), whereas the difference between the total plasma clearance of 99mTc-EC and 131I-OIH was highly significant (268 +/- 16 versus 185 +/- 9 ml min-1, P = 0.0001). 99mTc-EC had a significant hepatic clearance of 83 +/- 10 ml min-1 whereas the hepatic clearance of 131I-OIH was negligible. Renal plasma extraction of both 99mTc-EC and 131I-OIH decreased significantly between 2 and 240 min post-injection from 0.85 to 0.45% for 99mTc-EC and from 0.93 to 0.57% for 131I-OIH. Red blood cell binding of 99mTc-EC and 131I-OIH was 6.1% and 20%, respectively. The protein binding of 99mTc-EC and 131I-OIH was 32% for both tracers. We conclude that 99mTc-EC is not a suitable tracer for measuring renal function by the single-injection plasma clearance technique in pigs. This is due to a decreasing renal extraction and a significant hepatic clearance.