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80-kV Pulmonary CT Angiography With 40 mL of Iodinated Contrast Material in Lean Patients: Comparison of Vascular Enhancement With Iodixanol (320 mg I/mL)and Iomeprol (400 mg I/mL)

OBJECTIVE The purpose of this article is to compare the vascular enhancement obtained with a low-kilovoltage pulmonary CT angiography (CTA) protocol in lean patients, using 40 mL of a moderate-concentration isoosmolar (iodixanol, 320 mg I/mL) and a high-concentration low-osmolar (iomeprol, 400 mg I/mL) iodinated contrast medium injected at the same iodine delivery rate. SUBJECTS AND METHODS Forty-two lean patients (31 men and 11 women; body mass index, ≤ 23 kg/m(2)) with suspected pulmonary embolism and non-small cell lung carcinoma underwent pulmonary CTA with a 64-MDCT scanner using a tube voltage of 80 kV. Twenty-three patients (54.8%) received 40 mL of iodixanol (320 mg I/mL) injected at a rate of 5 mL/s, and the remaining 19 patients (45.2%) were administered an equal volume of iomeprol (400 mg I/mL) at a flow rate of 4 mL/s. Intraarterial density was measured in the common pulmonary artery trunk, the main right and left pulmonary arteries, lobar arteries, and at the segmental level, for a total of 15 regions of interest per patient. Intravascular enhancement homogeneity from central to subsegmental level was also assessed visually using a semiquantitative score (1 = poor, 2 = good, and 3 = excellent). RESULTS The overall vascular density of pulmonary arteries down to the segmental level was significantly higher with iodixanol (320 mg I/mL) than with iomeprol (400 mg I/mL) (p = 0.036). Enhancement homogeneity was good with both contrast agents, with no statistically significant difference between them (p = 0.8966). CONCLUSION In 80-kV pulmonary CTA of lean patients, higher intravascular enhancement can be achieved with 40 mL of iodixanol (320 mg I/mL) than with the same volume of iomeprol (400 mg I/mL), with good vessel conspicuity down to the subsegmental level.

Intraoperative radioguided sentinel lymph node biopsy in non-small cell lung cancer

OBJECTIVES The aim of this study was to determine the accuracy and the role of the sentinel lymph node (SLN) technique in patients with early non-small cell lung cancer (NSCLC). METHODS This study was carried out on 29 consecutive patients (M/F = 24:5, mean age 65.9 +/- 7.1 years) with resectable NSCLC (Stage IA-IB). Intraoperative injection with a (99m)Tc-nanocolloid suspension was performed in the first ten patients; the following patients were injected under computed tomography scan guidance. A total dose of 37 MBq (1 ml) was administered in two to four divided aliquots (depending on the size), injected in the periphery of the tumour. Intraoperative radioactivity counting started a mean of 1 h (range 50-70 min) after the injection. The SLN was defined as the node with the highest count rate using a handheld gamma probe counter. Resection with mediastinal node dissection was performed and findings were correlated with histologic and immunohistochemistry (IHC) examination. RESULTS Three of the 29 patients did not have NSCLC (two benign lesions, and one metastatic breast tumour) and were excluded. The SLN was identified in 25/26 (96.1%) patients (a total of 31 SLNs); 7/31 (22.5%) of the SLNs were positive for metastatic involvement after histologic and IHC examination. One inaccurately identified SLN was encountered (3.8%). CONCLUSIONS These preliminary results demonstrate the feasibility of this procedure in identifying the first site of potential nodal metastases of NSCLC. The actual clinical impact of this procedure remains to be elucidated by further investigation in larger groups of patients.

CT evaluation of chronic thromboembolic pulmonary hypertension

Eight patients with chronic thromboembolic pulmonary hypertension (CTPH) that had been demonstrated by perfusion lung scan, pulmonary arteriography, and right heart catheterization had their pulmonary circulation evaluated by CT. Eight subjects without lung pathology were also studied for comparison. High resolution CT from apex to base with 1 cm thick sections after intravenous injection of contrast medium was performed in each individual. Emboli lodged in main pulmonary arteries on arteriography were regularly shown by CT, whereas those in segmental or smaller arteries were not detected. Diameters of the main pulmonary arteries measured on CT correlated with systolic pulmonary artery pressure (p < 0.001). The ratio between diameters of segmental arteries and the corresponding bronchi (A/B ratio) on CT was > 1 in 72 of 144 examined pulmonary segments (18 segments for each patient) in patients with CTPH. The ratio was > 1 in only 10 of 144 examined segments in normal control subjects. Dilatation of bronchial arteries was present in four of eight patients with CTPH. The parenchymal density in patients with CTPH was significantly higher in the axial than in the middle or peripheral lung compartments. In conclusion, CT may help with the diagnosis of CTPH by detecting thrombi of main arteries and by showing characteristic findings; moreover, it is accurate in estimating pulmonary arterial pressure secondary to thromboembolic obstruction.

Effects of Contrast Media on Renal Hemodynamics and Tubular Function: Comparison between Diatrizoate and Iopamidol

The administration of iodinated radiologic contrast media (CM) is the third cause of acute renal failure: about 12% of the cases in hospitalized patients (1,2).

Renal Effects of Ionic and Nonionic Contrast Media: Comparison between Diatrizoate Meglumine and Iopamidol

Renal damage is a potential adverse side effect of the administration of iodinated contrast media (CM). Infact, CM represent one of the most frequent causes of renal failure (1,2). The renal damage determined by CM is sometimes irreversible (3). The mechanisms of this renal injury are not yet well understood. Hyperosmolality of the administered CM has been claimed to be an important factor of renal damage (4). No exhaustive data are available concerning the effects on renal function and nephrotoxicity of the different CM available. The aim of this study is the comparative evaluation of renal effects and nephrotoxicity of two different CM: diatrizoate meglumine (a high-osmolality ionic CM) and iopamidol (a new low-osmolality nonionic agent), after intravenous administration.