Multi-detector row helical CT of the liver: quantitative assessment of iodine concentration of intravenous contrast material on multiphasic CT--a prospective randomized study

PURPOSE: The purpose of this study was to assess the quantitative effects of contrast material concentration on hepatic parenchymal and vascular enhancement in multiphasic computed tomography (CT), using multi-detector row helical CT. MATERIALS AND METHODS: We designed a prospective randomized study to test two different concentrations of contrast material on five phasic scans of the liver. One hundred patients were randomly assigned to two groups: an iodine concentration of 300 mg/mL in group A and 370 mg/mL in group B. All patients received a fixed volume of 100 mL at a 4 mL/sec injection rate. Enhancement values for the hepatic parenchyma and aorta at three levels (upper, middle, and lower level of the liver), and values for portal and hepatic veins were statistically compared between the two groups. RESULTS: Hepatic parenchymal enhancement values at all levels of the liver in portal phase (PP) and equilibrium phase (EP) were significantly higher in group B than in group A (p<0.01). Aortic enhancement values at two levels of the liver (middle and lower) in early hepatic arterial phase (EAP) were significantly higher in group B than in group A (p<0.05), however, there was no significant difference between groups A and B in aortic enhancement during the delayed hepatic arterial phase (DAP). Portal and hepatic venous enhancement values in PP and EP were significantly higher in group B than in group A (p<0.01). CONCLUSION: On multiphasic dynamic CT, the use of a higher iodine concentration of contrast material results in higher hepatic parenchymal enhancement and aortic enhancement, as well as higher portal and hepatic venous enhancement.     

Transthoracic CT-guided biopsy with multiplanar reconstruction image improves diagnostic accuracy of solitary pulmonary nodules

OBJECTIVE: To evaluate the utility of multiplanar reconstruction (MPR) image for CT-guided biopsy and determine factors of influencing diagnostic accuracy and the pneumothorax rate. MATERIALS AND METHODS: 390 patients with 396 pulmonary nodules underwent transthoracic CT-guided aspiration biopsy (TNAB) and transthoracic CT-guided cutting needle core biopsy (TCNB) as follows: 250 solitary pulmonary nodules (SPNs) underwent conventional CT-guided biopsy (conventional method), 81 underwent CT-fluoroscopic biopsy (CT-fluoroscopic method) and 65 underwent conventional CT-guided biopsy in combination with MPR image (MPR method). Success rate, overall diagnostic accuracy, pneumothorax rate and total procedure time were compared in each method. Factors affecting diagnostic accuracy and pneumothorax rate of CT-guided biopsy were statistically evaluated. RESULTS: Success rates (TNAB: 100.0%, TCNB: 100.0%) and overall diagnostic accuracies (TNAB: 96.9%, TCNB: 97.0%) of MPR were significantly higher than those using the conventional method (TNAB: 87.6 and 82.4%, TCNB: 86.3 and 81.3%) (P < 0.05). Diagnostic accuracy were influenced by biopsy method, lesion size, and needle path length (P < 0.05). Pneumothorax rate was influenced by pathological diagnostic method, lesion size, number of punctures and FEV1.0% (P < 0.05). CONCLUSION: The use of MPR for CT-guided lung biopsy is useful for improving diagnostic accuracy with no significant increase in pneumothorax rate or total procedure time.     

A review and development of sentinel node navigation surgery for lung cancer

Sentinel node navigation surgery (SNNS) for lung caner has not yet been established. Sentinel node (SN) identification using dye or radioisotope has been developed; however, the SN identification rate was less than 50% in the dye method and use of radioisotopes is strongly restricted in Japan. The novel method using a CT or MRI contrast medium are expected. A study of local immune reaction for lung cancer in SN is also a very interesting issue.     

Extensive proliferation of T cell lineage-restricted progenitors in the thymus: an essential process for clonal expression of diverse T cell receptor beta chains

For clonal diversification of TCR, a large number of T cell progenitors are required in which highly diverse TCRbeta chains are accommodated individually. In the present study, we examined the proliferative potential of thymic progenitors that have been defined to be T cell lineage restricted. We show that the earliest fetal thymus (FT) cells from Rag2(-/-) mice, when cultured individually in a thymic organ culture system, produced 150-1,800 CD25(+) cells. Since differentiation and proliferation of Rag2(-/-) thymocytes are arrested at the stage of TCRbeta chain gene rearrangement, the observed proliferation was considered to represent the proliferative potential of progenitors prior to the TCRbeta rearrangement. A comparable level of proliferation was revealed to occur by analyzing the Dbeta-Jbeta rearrangement profiles of T cells generated from single progenitors in the earliest population of FT from normal mice. The proliferative potential of progenitors declined along with the progression of developmental stages. Such an extensive proliferation of progenitors after the restriction to the T cell lineage may be an essential process ensuring the clonal diversification of TCRbeta chains.     

Effect of radioisotope sentinel node mapping in patients with cT1 N0 M0 lung cancer

BACKGROUND: Application of the sentinel node concept to lung cancer is still controversial. Patients with peripheral small lung cancers would gain the most benefit from this concept, if it were valid. We sought to determine whether it is possible to choose between limited lymph node sampling and systematic lymphadenectomy from the distribution of sentinel lymph nodes in patients with node-negative disease on the basis of imaging. METHODS: Sixty-five consecutive patients with cT1 N0 M0 non-small cell lung cancer were enrolled. A radioisotope tracer (4 mCi of technetium-99m tin colloid, 2.0 mL) was injected in the vicinity of the tumor before surgical intervention with computed tomographic guidance. The radioactivity of each resected lymph node was measured separately with a hand-held gamma probe after complete tumor resection. Sentinel nodes were identified, and the accuracy of sentinel node mapping was examined. Whether the location of the sentinel node depended on the site of the primary tumor was also examined. RESULTS: Of the 65 patients, 3 were excluded because of the final pathologic results. Successful radionuclide migration occurred in 39 (62.9%) of the 62 patients. There was 1 (2.6%) false-negative result among 39 patients with a sentinel node, and therefore the sensitivity was 90%, and the specificity was 100%. The most common sentinel lymph nodes were at level 12 (46.7%), followed by level 11 (18.3%), the mediastinum (16.7%), and level 10 (11.7%). CONCLUSION: The sentinel node concept is valid in patients with cT1 N0 M0 lung cancer. The lobar lymph nodes were identified as sentinel nodes more frequently than other lymph nodes. We need to make further efforts to increase the sentinel node identification rate. However, we believe that if sentinel nodes are identified, sentinel node mapping can allow the accurate intraoperative diagnosis of pathologic N0 status in patients with cT1 N0 M0 lung cancer.     

A prospective survey of delayed adverse reactions to iohexol in urography and computed tomography

We investigated 7505 inpatients who underwent intravenous urography or contrast-enhanced computed tomography to assess risk factors for delayed adverse drug reactions to iohexol, a non-ionic iodinated contrast medium. Focusing on delayed adverse reactions, all adverse events were prospectively investigated for 7 days after injection of iohexol. To explore the relevant risk factors, the relationship between occurrence of adverse reactions to iohexol and 17 different variables was evaluated by logistic regression analysis. To assess the influence of seasonal factors, adverse reactions were separately evaluated during two periods: February to April (the pollinosis period in Japan) and July to September (the non-pollinosis period). The prevalence of delayed adverse events and delayed adverse reactions was 3.5 and 2.8%, respectively, whereas the prevalence of adverse events and adverse reactions was 5.7 and 5.0%, respectively. Multivariate analysis showed that six parameters had a significant influence on delayed adverse reactions to iohexol, including (a) a history of allergy, (b) season, (c) radiographic procedure, (d) age, (e) concomitant surgery or other invasive procedures, and (f) concomitant medication. The prevalence of delayed reactions was lower than in previous large-scale studies. Significant risk factors included a history of allergy and performance of radiography during the pollinosis period, suggesting that allergy was involved in delayed adverse reactions. The type of radiographic procedure also had an influence. Electronic Publication     

Comparison of three tracers for detecting sentinel lymph nodes in patients with clinical N0 lung cancer

The goal of this pilot study was to compare three tracers for the detection of sentinel nodes in patients with lung cancer. Forty-eight patients with clinical N0 non-small cell lung cancer were enrolled. Indocyanine green (n=16) or isosulfan blue (n=18) was injected around the tumor intraoperatively, or technetium tin colloid was injected preoperatively under CT guidance (n=14). Sentinel nodes were detected in 6.3% of patients injected with indocyanine green, 50.0% of patients injected with isosulfan blue, and 64.3% of patients injected with technetium tin colloid. The detection rate achieved with indocyanine green was significantly lower than with the other two tracers. A false-negative sentinel node was seen in 1 patient using isosulfan blue. Both isosulfan blue and technetium tin colloid seem to be suitable for intraoperative sentinel node mapping in patients with lung cancer.     

Radiographic pulmonary and pleural changes after carbon ion irradiation

PURPOSE: For the treatment of Stage I non-small-cell lung cancers, a Phase I/II study of carbon ion irradiation was undertaken. In the present study, we focus on posttreatment radiographic lung damage: specifically, its timing, features, and relation to dose-volume factors. MATERIALS AND METHODS: Forty-three patients with 44 Stage I non-small-cell lung cancers were treated with carbon ion irradiation ranging from 59.4 to 95.4 photon Gy equivalent dose (GyE) in 18 fractions over 6 weeks, according to our dose escalation protocols. Primary lesions were irradiated by 2-4 portals. Follow-up evaluation with computed tomography (CT) was sequentially performed to assess changes in the lung. CT findings were classified into two categories: pulmonary reaction and pleural reaction. A dose-volume histogram for each patient was calculated, using a three-dimensional CT planning system. Statistical analysis was conducted using Spearman's rank test. RESULTS: The median appearance period of pulmonary reactions was 3 months after the start of carbon ion irradiation, whereas the maximum period was 6 months. The severity of pulmonary reactions statistically correlated with lung volumes irradiated no less than 20 GyE (vol. 20) and 40 GyE (vol. 40) (p = 0.017 and p = 0.0089). Geometrically unique findings in the irradiated fields were observed in 7 patients (16%). The median appearance period of pleural reactions was 4 months after the start of carbon ion irradiation. The occurrence of pleural reactions significantly correlated with planning target volume (p = 0.000098), vol. 20 (p = 0.00011), and vol. 40 (p = 0.00097). CONCLUSIONS: Lung damage after carbon ion irradiation was observed in the parenchyma and in the pleura. The severity of pulmonary reactions was correlated with dose-volume factors. These findings might provide useful information in the planning and management of carbon ion irradiation.