Tae Sung Kim

Volume-Based Parameter of 18F-FDG PET/CT in Malignant Pleural Mesothelioma: Prediction of Therapeutic Response and Prognostic Implications

BackgroundTo evaluate the importance of assessing volume-based parameter of 18F-FDG PET/CT in patients with malignant pleural mesothelioma (MPM) for the prediction of response and patient outcome early in the course of treatment.Materials and MethodsPatients (nxa0=xa013; M:Fxa0=xa09:4, mean age, 54xa0years) with histopathologically proven MPM, all of whom were scheduled to undergo curative extrapleural pneumonectomy (EPP) or palliative chemotherapy, were included in this study. They were evaluated using integrated 18F-FDG PET/CT at baseline. Maximum standardized uptake value (SUVmax), average SUV (SUVavg), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured using PET/CT data. Relationships between tumor progression and PET parameters were statistically analyzed.ResultsOf the 13 patients, 8 (62%) developed disease recurrence after surgery or tumor progression after chemotherapy (median follow-up, 329xa0days; range, 28–536xa0days). Between subgroups with and without tumor progression, significant differences were noted in MTV (Pxa0=xa00.045). On ROC curve analysis, MTV (AUCxa0=xa00.850, 95% confidence interval [95% CI] 0.550–0.977) and TLG (AUCxa0=xa00.800, 95% CI 0.494–0.960) showed good predictive performance for tumor progression. Multivariate analysis adjusted for treatment modality showed that MTV (HR 1.003, Pxa0=xa00.025) and TLG (HR 1.001, Pxa0=xa00.031) were independent factors associated with tumor progression. Time to tumor progression was shorter in patients with a high volume-based parameter of PET than in those with a low value.ConclusionsVolume-based parameters of 18F-FDG PET/CT have the potential to provide prognostic information in MPM patients who are receiving surgery or palliative chemotherapy.

Thin-Section CT Findings of Nontuberculous Mycobacterial Pulmonary Diseases: Comparison Between Mycobacterium avium-intracellulare Complex and Mycobacterium abscessus Infection

We aimed to compare the CT findings of nontuberculous mycobacterial pulmonary diseases caused by Mycobacterium avium-intracellulare complex (MAC) and Mycobacterium abscessus. Two chest radiologists analyzed retrospectively the thin-section CT findings of 51 patients with MAC and 36 with M. abscessus infection in terms of patterns and forms of lung lesions. No significant difference was found between MAC and M. abscessus infection in the presence of small nodules, tree-in-bud pattern, and bronchiectasis. However, lobar volume decrease (p=0.001), nodule (p=0.018), airspace consolidation (p=0.047) and thin-walled cavity (p=0.009) were more frequently observed in MAC infection. The upper lobe cavitary form was more frequent in the MAC (19 of 51 patients, 37%) group than M. abscessus (5 of 36, 14%) (p=0.029), whereas the nodular bronchiectatic form was more frequent in the M. abscessus group ([29 of 36, 81%] vs. [27 of 51, 53%] in MAC) (p=0.012). In conclusion, there is considerable overlap in common CT findings of MAC and M. abscessus pulmonary infection; however, lobar volume loss, nodule, airspace consolidation, and thin-walled cavity are more frequently seen in MAC than M. abscessus infection.

Optimal Duration of IV and Oral Antibiotics in the Treatment of Thoracic Actinomycosis

STUDY OBJECTIVEnIV antibiotic therapy for 2 to 6 weeks followed by 6 to 12 months of oral antibiotic therapy is usually recommended for the treatment of thoracic actinomycosis. The objective of this study was to evaluate the duration of IV and oral antibiotic therapy for thoracic actinomycosis.nnnMETHODSnWe present a retrospective case series of 28 patients with thoracic actinomycosis as confirmed by histopathology from October 1994 through December 2003.nnnRESULTSnAfter diagnosis of actinomycosis, 54% (15 of 28 patients) received antibiotic therapy alone. The duration of IV antibiotic therapy ranged from 0 to 18 days (median, 2 days; interquartile range [IQR], 0 to 3 days), and the duration of oral antibiotic treatment ranged from 76 to 412 days (median, 167 days; IQR, 142 to 214 days) in patients who received antibiotics alone. Combination surgical and antibiotic therapy occurred in 46% (13 of 28 patients). The duration of IV antibiotic therapy ranged from 3 to 17 days (median, 8 days; IQR, 5 to 13 days), and the duration of oral antibiotic therapy ranged from 0 to 534 days (median, 150 days; IQR, 3.5 to 289 days) in these patients. Clinical cures were achieved in 96% (27 of 28 patients). There was no clinical evidence of recurrence during follow-up period at our hospital (median, 23 months; IQR, 9 to 44 months) in 21 patients, excluding 7 patients who were transferred to referring hospitals after completion of antibiotic therapy (n = 6) or during antibiotic therapy (n = 1).nnnCONCLUSIONSnThoracic actinomycosis is best treated with individualized therapeutic modalities, depending on factors such as the initial burden of disease, the performance of resectional surgery, and the clinical and radiologic responses to therapy. The traditional recommendation of IV antibiotic therapy for 2 to 6 weeks followed by oral antibiotic therapy for 6 to 12 months is not always necessary for all thoracic actinomycosis patients.

Six-month Therapy with Aerosolized Interferon-γ for Refractory Multidrug-Resistant Pulmonary Tuberculosis

The aim of this study was to investigate the adjuvant effects of interferon-gamma (IFN-γ) inhalation therapy for six months in the treatment of refractory multidrug-resistant pulmonary tuberculosis (MDR-TB). Aerosolized IFN-γ was given to six MDR-TB patients with persistent positive smears and cultures despite long-term medical treatment. The patients received aerosolized two million international units of IFN-γ three times a week for 6 months while they continued on identical antituberculous chemotherapy. Before IFN-γ inhalation therapy, the patients received a median of 6.5 (range, 4 to 7) antituberculous drugs for median duration of 29 months (range,7 to 76). After IFN-γ inhalation therapy, sputum smears remained persistently positive in all patients throughout the study period. Sputum cultures were transiently negative at the 4th month in two patients, but became positive again at the end of 6 months of IFN-γ therapy. Five patients had radiological improvement including three patients who showed a decrease in the size of the cavitary lesions. Resectional surgery could be performed in one patient in whom substantial clinical and radiological improvement was noted after IFN-γ inhalation therapy. These results suggest that IFN-γ inhalation therapy may be effective for some cases of refractory MDR-TB who are otherwise not responding to conventional therapy.

Lung cancer screening with low-dose helical CT in Korea: experiences at the Samsung Medical Center.

To determine overall detection rates of lung cancer by low-dose CT (LDCT) screening and to compare histopathologic and imaging differences of detected cancers between high- and low-risk groups, this study included 6,406 asymptomatic Korean adults with ≥45 yr of age who underwent LDCT for lung cancer screening. All were classified into high- (≥20 pack-year smoking; 3,353) and low-risk (3,053; <20 pack-yr smoking and non-smokers) groups. We compared CT findings of detected cancers and detection rates between high- and low-risk. At initial CT, 35% (2,255 of 6,406) had at least one or more non-calcified nodule. Lung cancer detection rates were 0.36% (23 of 6,406). Twenty-one non-small cell lung cancers appeared as solid (n=14) or ground-glass opacity (GGO) (n=7) nodules. Cancer likelihood was higher in GGO nodules than in solid nodules (p<0.01). Fifteen of 23 cancers occurred in high-risk group and 8 in low-risk group (p=0.215). Therefore, LDCT screening help detect early stage of lung cancer in asymptomatic Korean population with detection rate of 0.36% on a population basis and may be useful for discovering early lung cancer in low-risk group as well as in high-risk group.

The spectrum of benign esophageal lesions: imaging findings.

Benign esophageal lesions occur in various diseases. Barium studies are useful for the evaluation of mucosal surface lesions but provide little information about the extramucosal extent of disease. Computed tomography and magnetic resonance imaging, on the other hand, permit the assessment of wall thickness, mediastinal involvement, adjacent lymphadenopathy, and distant spread. In diseases such as fibrovascular polyps, duplication cysts, scleroderma, trauma, caustic esophagitis, hiatal hernia, esophageal diverticulum, achalasia, and paraesophageal varices, the findings of imaging studies are specific, obviating the need for further invasive diagnostic work-up. The advent of helical computed tomography and its volume data set allows the acquisition of multiplanar images, and magnetic resonance imaging is useful both for this and for tissue characterization. Thus, multiplanar cross-sectional imaging further extends the role of imaging modalities to the evaluation of benign esophageal lesions. Through an awareness of the multiplanar cross-sectional appearances of various benign esophageal lesions, the radiologist can play an important role in the detection, diagnosis, further diagnostic planning, and treatment of the diseases in which they occur.

Efficacy of PET/CT in the characterization of solid or partly solid solitary pulmonary nodules

We aimed to evaluate the efficacy of (18)fluorine fluorodeoxyglucose ((18)F FDG) PET/CT for the characterization of solitary pulmonary nodules (SPNs) compared with the use of PET alone or CT alone. Our institutional review board approved this retrospective study with a waiver of informed consent. We selected 100 patients (M:F=56:44, mean age; 58 years) with a pathologically proven solid or partly solid SPN. Three chest radiologists assessed the nodule characteristics independently and retrospectively. Diagnostic efficacies were compared for three different approaches: consideration of CT findings only, PET findings only, and both PET and CT findings. The McNemar test, kappa statistics, and receiver operating characteristics (ROC) curve analysis were performed. Sixty patients had benign and 40 had malignant nodules. Overall sensitivity values for malignant SPNs for CT, PET and PET/CT were 82%, 88%, and 88%, respectively, whereas the specificity values were 66%, 71%, and 77%, respectively. PET/CT was significantly better in terms of specificity than the use of PET alone or CT alone (P<.05). The areas under curve (Az) values for the ROC analyses of PET/CT and PET alone, respectively, were larger than that of CT alone (P<.05). Interobserver agreement was moderate (kappa=0.46-0.56) for CT, good to excellent (kappa=0.78-0.90) for PET, and good for PET/CT (kappa=0.64-0.78). For the characterization of SPNs, integrated PET/CT provides significantly better specificity than CT alone or PET alone and both integrated PET/CT and PET alone allow more confidence than CT alone.

Cytomegalovirus Pneumonia: High-Resolution CT Findings in Ten Non-AIDS Immunocompromised Patients

Objective To describe the HRCT findings of cytomegalovirus (CMV) pneumonia in non-AIDS immunocompromised patients. Materials and Methods This retrospective study involved the ten all non-AIDS immunocompromised patients with biopsy-proven CMV pneumonia and without other pulmonary infection encountered at our Medical Center between January 1997 and May 1999. HRCT scans were retrospectively analysed by two chest radiologists and decisions regarding the findings were reached by consensus. Results The most frequent CT pattern was ground-glass opacity, seen in all patients, with bilateral patchy (n = 8) and diffuse (n = 2) distribution. Other findings included poorly-defined small nodules (n = 9) and consolidation (n = 7). There was no zonal predominance. The small nodules, bilateral in eight cases and unilateral in one, were all located in the centrilobular region. Consolidation (n = 7), with patchy distribution, was bilateral in five of seven patients (71%). Pleural effusion and bilateral areas of thickened interlobular septa were seen in six patients (60%). Conclusion CMV pneumonia in non-AIDS immunocompromised patients appears on HRCT scans as bilateral mixed areas of ground-glass opacity, poorly-defined centrilobular small nodules, and consolidation. Interlobular septal thickening and pleural effusion are frequently associated.

Unsuspected pulmonary emboli in lung cancer patients: the impact on survival and the significance of anticoagulation therapy.

BACKGROUNDnMany pulmonary emboli (PE) are detected unsuspectedly in lung cancer patients. The purpose of our study was to retrospectively evaluate the role of anticoagulation therapy for unsuspected PE in lung cancer patients. We also aimed to evaluate risk factors associated with the development of PE as well as the prognostic power of PE in lung cancer patients.nnnPATIENTS AND METHODSnThe Samsung Medical Information System was used to evaluate predictors and prognosis of PE in lung cancer patients. We found patients with PE using the Radiation Interpretation Registry and reviewed their medical records.nnnRESULTSnAmong 8014 lung cancer patients, PE developed in 180 patients (cumulative incidence rates=2.2%). Metastasis and prior history of chemotherapy were significant predictors of the development of PE. Pulmonary embolism detected within 3 months after diagnosis of lung cancer was a significant poor prognostic factor (hazard ratio [HR], 1.5; 95% CI, 1.1-2.0) in the complete lung cancer cohort. One hundred thirteen (63%) out of total 180 PE patients were incidentally found to have PE. Among the 113 patients with unsuspected PE, 62 patients (55%) did not receive anticoagulation therapy, and died sooner than those who received anticoagulation therapy for unsuspected PE (HR, 4.1; 95% CI, 2.3-7.6).nnnCONCLUSIONnAnticoagulation therapy for unsuspected PE is associated with increased overall survival in lung cancer patients.

Diagnostic Efficacy of PET/CT Plus Brain MR Imaging for Detection of Extrathoracic Metastases in Patients with Lung Adenocarcinoma

We aimed to evaluate prospectively the efficacy of positron emission tomography (PET)/computed tomography (CT) plus brain magnetic resonance imaging (MRI) for detecting extrathoracic metastases in lung adenocarcinoma. Metastatic evaluations were feasible for 442 consecutive patients (M:F=238:204; mean age, 54 yr) with a lung adenocarcinoma who underwent PET/CT (CT, without IV contrast medium injection) plus contrast-enhanced brain MRI. The presence of metastases in the brain was evaluated by assessing brain MRI or PET/CT, and in other organs by PET/CT. Diagnostic efficacies for metastasis detection with PET/CT plus brain MRI and with PET/CT only were calculated on a per-patient basis and compared from each other. Of 442 patients, 88 (20%, including 50 [11.3%] with brain metastasis) had metastasis. Regarding sensitivity of overall extrathoracic metastasis detection, a significant difference was found between PET/CT and PET/CT plus brain MRI (68% vs. 84%; P=0.03). As for brain metastasis detection sensitivity, brain MRI was significantly higher than PET/CT (88% vs. 24%; P<0.001). By adding MRI to PET/CT, brain metastases were detected in additional 32 (7% of 442 patients) patients. In lung adenocarcinoma patients, significant increase in sensitivity can be achieved for detecting extrathoracic metastases by adding dedicated brain MRI to PET/CT and thus enhancing brain metastasis detection.