Soo Jin Choi

Multidetector computed tomography chest examinations with low-kilovoltage protocols in adults: effect on image quality and radiation dose.

Objective: The purpose of our study was to assess the effect on image quality and radiation dose of chest multidetector computed tomography (CT) examinations with low-kilovoltage protocols for adults. Methods: This study was approved by the institutional review board of our medical center. Two hundred ten patients (83 women, 127 men; mean age, 56.1 years) requiring contrast-enhanced chest CT examination were randomly assigned to 1 of 3 protocol groups: (1) protocol A, the standard protocol, with 120 kilovolt (peak) (kV[p]) and 100 effective milliampere-second (eff mA s); (2) protocol B, with 100 kV(p) and 140 eff mA s; and (3) protocol C, with 80 kV(p) and 180 eff mA s. Each group included 70 patients. Contrast material injection protocols were standardized for all groups. Three radiologists blinded to the CT parameters used assessed images in random order for 20 items from 4 anatomical regions. They ranked the subjective image quality using a 4-point scale. The volume computed tomography dose index (CTDIvol) and dose length product (DLP) were displayed by the CT unit after the automatic exposure control-driven acquisition was recorded for each group; the differences were analyzed for statistical significance. Results: When the overall agreement was pooled from the 3 observers, the qualitative score analysis revealed no significant difference between the 100-kV(p) and the standard protocols (P > 0.05). However, when the scores were compared between the 80-kV(p) and the standard protocols, a marginal significance (P = 0.054) was observed. When the patients in the group with an 80-kV(p) protocol were subcategorized according to body mass index (BMI), the image quality scores of all BMI subgroups, of the 80-kV(p) protocol, were not significantly different from those of the standard protocol. However, an increase in the BMI tended to be associated with a decrease in the subjective image quality. The mean values of CTDIvol for 120-, 100-, and 80-kV(p) protocols were 5.042, 4.507, and 2.883, respectively. The mean values of DLP for each protocol were 187.5, 158.7, and 105.8, respectively. The CTDIvol and DLP of the low-kilovoltage protocols were significantly lower than those of the standard protocol (P < 0.01). The DLP of the 100- and 80-kV(p) protocols were reduced radiation exposure doses in 15.36% and 43.57%, respectively, as compared with the standard protocol. Conclusions: The use of low-kilovoltage protocol resulted in a significant reduction in the radiation exposure at chest CT, with image qualities comparable with those of the standard protocols.

Acute necrotizing encephalopathy in Korean infants and children: imaging findings and diverse clinical outcome.

Objective The purpose of our study was to describe acute necrotizing encephalopathy in Korean infants and children, and we sought to evaluate the prognostic factors. Materials and Methods Acute necrotizing encephalopathy was diagnosed in 14 Korean infants and children. We retrospectively analyzed the neuroimaging findings including the follow-up changes. The clinical course of the disease was graded, and we evaluated prognostic factors including age, serum level of the aminotransferase, hemorrhage, and localized atrophy of the brain. Results This encephalopathy predominantly affected the bilateral thalami (n=14), pons (n=12), and midbrain (n=10) in a symmetrical pattern. Hemorrhage was observed in eight patients (57%). On the follow-up images (n=12), the brain lesions were reduced in extent for all patients, and generalized atrophy was seen in six patients. Localized tissue loss was observed in five patients and a complete resolution occurred for one patient. All the patients survived and two recovered completely; mild (n=6) to severe (n=6) neurological deficits persisted in the remaining 12 patients. The significant prognostic factors identified in this study were the presence of hemorrhage (p = 0.009) and localized atrophy (p = 0.015). Conclusion Acute necrotizing encephalopathy in Korean patients showed the characteristic patterns of the post-infectious encephalopathy as described in the literature. The high survival rate and the relatively favorable clinical course observed for the present study suggest a more diverse spectrum of disease severity than was previously described. The presence of hemorrhage and localized tissue loss on MR images may suggest a poor prognosis.

Two Cases of Interstitial Pneumonitis Caused by Rituximab Therapy

Rituximab, a chimeric monoclonal antibody directed against CD20, has become a part of the standard therapy for patients with non-Hodgkins lymphoma either in combination with other drugs or as a single agent. The CD20 antigen is expressed on 95% of B-cell lymphoma cells and normal B-cells but, is not found on precursor B-cells or stem cells. Rituximab is now approved for patients with diffuse large B-cell lymphoma when combined with standard CHOP chemotherapy (cyclophosphamide, doxorubicin, vincristine and prednisone) or patients with follicular lymphoma who have failed first line chemotherapy. The monoclonal antibody is generally well tolerated. Most of the adverse events are infusion-associated, mild to moderate non-hematological toxicities. Severe respiratory adverse events have been infrequent. Here, we report two patients with non-Hodgkins lymphoma in whom interstitial pneumonitis developed with rituximab therapy.

Randomized phase II trial of two different schedules of docetaxel plus cisplatin as first‐line therapy in advanced nonsmall cell lung cancer

There is increasing interest in the use of a weekly administration of docetaxel as a way of reducing its hematologic toxicity. The purpose of the current randomized study was to evaluate the toxicity and efficacy of docetaxel plus cisplatin combination on 2 schedules in patients with previously untreated, advanced nonsmall‐cell lung cancer (NSCLC).

Solitary fibrous tumor of the trachea: CT findings with a pathological correlation.

We present the multidetector CT findings with a pathologic correlation for the case of a solitary fibrous tumor located in the trachea. The MDCT revealed a well-circumscribed intraluminal mass arising from the trachea, with strong nodular enhancement in the periphery of the mass. The enhancement pattern of the mass corresponded histopathologically to a focal hypocellular area in the center and prominent blood vessels along the periphery of the mass. We also present volume-rendered and virtual bronchoscopic images of this rare submucosal tracheal tumor.

Reverse Redistribution in Myocardial Perfusion Imaging: Revisited with 64-slice MDCT.

The authors report myocardial perfusion imaging of a patient showing reverse redistribution (RR) and a 64-slice multidetector-row computed tomography (MDCT) with corresponding findings. The patient had subendocardial myocardial infarction (MI) with positive electrocardiogram (EKG) findings and elevated levels of cardiac isoenzymes. Experiencing this case emphasizes the importance of complementary correlation of a new diagnostic modality that helps us to understand the nature of RR.