Kyung Won Lee

Multimodality Assessment of Esophageal Cancer: Preoperative Staging and Monitoring of Response to Therapy

Esophageal cancer is a leading cause of cancer mortality worldwide. Complete resection of esophageal cancer and adjacent malignant lymph nodes is the only potentially curative treatment. Accurate preoperative staging and assessment of therapeutic response after neoadjuvant therapy are crucial in determining the most suitable therapy and avoiding inappropriate attempts at curative surgery. Computed tomography (CT) is recommended for initial imaging following confirmation of malignancy at pathologic analysis, primarily to rule out unresectable or distant metastatic disease. With the advent of multidetector CT, use of thin sections and multiplanar reformation allows more accurate staging of esophageal cancer. Endoscopic ultrasonography (US) is the best modality for determining the depth of tumor invasion and presence of regional lymph node involvement. Combined use of fine-needle aspiration and endoscopic US can improve assessment of lymph node involvement. Positron emission tomography (PET) is useful for assessment of distant metastases but is not appropriate for detecting and staging primary tumors. PET may also be helpful in restaging after neoadjuvant therapy, since it allows identification of early response to treatment and detection of interval distant metastases. Each imaging modality has its advantages and disadvantages; therefore, CT, endoscopic US, and PET should be considered complementary modalities for preoperative staging and therapeutic monitoring of patients with esophageal cancer.

Diagnostic accuracy of CT-guided core biopsy of ground-glass opacity pulmonary lesions

OBJECTIVEnThe purpose of our study was to evaluate the accuracy of CT-guided percutaneous core biopsy of ground-glass opacity (GGO) pulmonary lesions.nnnMATERIALS AND METHODSnThe study included 50 patients (24 men, 26 women; age range, 43-78 years) who had a GGO pulmonary lesion and underwent CT-guided core biopsy. Diagnostic accuracy was compared between two groups according to lesion size (< 2 cm vs > or = 2 cm) and GGO component (> 90% vs 50-90%). Each case was reviewed for complications, including pneumothorax, thoracostomy tube insertion, and hemoptysis.nnnRESULTSnMalignancy was finally diagnosed in 33 patients, including three who underwent repeated biopsies, with 33 true-positive and three false-negative findings for an overall sensitivity of 92% (33/36). A benign lesion was finally diagnosed in 10 patients with one false-positive result, for a specificity of 90%. Two benign lesions without confirmative diagnosis because of loss of follow-up and five nondiagnostic samples were excluded from the calculations of sensitivity, specificity, and diagnostic accuracy. The overall diagnostic accuracy was 91%, with a positive predictive value of 97% and a negative predictive value of 75%. Sensitivity and accuracy were not significantly different between the two groups of lesion size and GGO components (p = 0.0491). Ten (18%) patients had pneumothorax, with one (2%) requiring placement of a thoracostomy tube. Mild hemoptysis occurred in seven (13%) patients.nnnCONCLUSIONnCT-guided core biopsy of GGO lesions can yield high diagnostic accuracy and acceptable complication rates approaching those of solid lesions.

Epidermal Growth Factor Receptor Mutation and Pathologic-Radiologic Correlation Between Multiple Lung Nodules with Ground-Glass Opacity Differentiates Multicentric Origin from Intrapulmonary Spread

Introduction: No standard guidelines detailing recommendations for the selection and treatment for multiple lung nodules with ground-glass opacity (GGO) have been established. For treatment decision, we analyzed epidermal growth factor receptor (EGFR)/K-ras somatic aberrations and pathologic-radiologic correlation in multiple lung nodules presented as GGO to differentiate multifocal lesions from intrapulmonary spread. Methods: Twenty-four patients with multiple lung nodules presented as GGO were identified to investigate somatic mutations of EGFR (exon 18–21) and K-ras (codons 2, 13, and 61). This series included 18 atypical adenomatous hyperplasias (AAH), 15 bronchioloalveolar carcinomas (BAC), and 23 adenocarcinomas (ADC) obtained from 24 patients. Results: High frequency of discordant EGFR mutations (17 of 24, 70.8%) could discriminate tumor clonality (18 of 24, 75%) of multiple lung neoplastic nodules presented as GGO. EGFR mutations were common in AAH (38.9%), BAC (46.7%), and ADC (39.1%). In case 4, AAH and BAC had different mutational changes, and in case 10, the BAC lesion contains EGFR mutation that is not in the invasive ADC. In case 17, the BAC had more mutational changes than the carcinoma. The pure GGO appearance in the radiologic examination corresponded preinvasive pathologic change. Conclusions: This study showed that synchronous BAC and/or ADC can have different EGFR or K-ras mutational profiles suggesting these lesions arise as independent events rather than intrapulmonary spread or systemic metastasis. This has significant implication in staging and treatment. These findings might be a clue to establish guidelines of the multiple neoplastic lung nodules with GGO.

Pulmonary Nodular Ground-Glass Opacities in Patients With Extrapulmonary Cancers: What is Their Clinical Significance and How Can We Determine Whether They Are Malignant or Benign Lesions?

BACKGROUNDnThe clinical significance of pulmonary nodular ground-glass opacities (NGGOs) in patients with extrapulmonary cancers is not known, although there is an urgent need for study on this topic. The purpose of this study, therefore, was to investigate the clinical significance of pulmonary NGGOs in these patients, and to develop a computerized scheme to distinguish malignant from benign NGGOs.nnnMETHODSnFifty-nine pathologically proven pulmonary NGGOs in 34 patients with a history of extrapulmonary cancer were studied. We reviewed the CT scan characteristics of NGGOs and the clinical features of these patients. Artificial neural networks (ANNs) were constructed and tested as a classifier distinguishing malignant from benign NGGOs. The performance of ANNs was evaluated with receiver operating characteristic analysis.nnnRESULTSnTwenty-eight patients (82.4%) were determined to have malignancies. Forty NGGOs (67.8%) were diagnosed as malignancies (adenocarcinomas, 24; bronchioloalveolar carcinomas, 16). Among the rest of the NGGOs, 14 were atypical adenomatous hyperplasias, 4 were focal fibrosis, and 1 was an inflammatory nodule. There were no cases of metastasis appearing as NGGOs. Between malignant and benign NGGOs, there were significant differences in lesion size; the presence of internal solid portion; the size and proportion of the internal solid portion; the lesion margin; and the presence of bubble lucency, air bronchogram, or pleural retraction (p < 0.05). Using these characteristics, ANNs showed excellent accuracy (z value, 0.973) in discriminating malignant from benign NGGOs.nnnCONCLUSIONSnPulmonary NGGOs in patients with extrapulmonary cancers tend to have high malignancy rates and are very often primary lung cancers. ANNs might be a useful tool in distinguishing malignant from benign NGGOs.

Managing the CT Data Explosion: Initial Experiences of Archiving Volumetric Datasets in a Mini-PACS

Two image datasets (one thick section dataset and another volumetric dataset) were typically reconstructed from each single CT projection data. The volumetric dataset was stored in a mini-PACS with 271-Gb online and 680-Gb nearline storage and routed to radiologists’ workstations, whereas the thick section dataset was stored in the main PACS. Over a 5-month sample period, 278 Gb of CT data (8976 examinations) was stored in the main PACS, and 738 Gb of volumetric datasets (6193 examinations) was stored in the mini-PACS. The volumetric datasets formed 32.8% of total data for all modalities (2.20 Tb) in the main PACS and mini-PACS combined. At the end of this period, the volumetric datasets of 1892 and 5162 examinations were kept online and nearline, respectively. Mini-PACS offers an effective method of archiving every volumetric dataset and delivering it to radiologists.

Regional variance of visually lossless threshold in compressed chest CT images: Lung versus mediastinum and chest wall

OBJECTIVEnTo estimate the visually lossless threshold (VLT) for the Joint Photographic Experts Group (JPEG) 2000 compression of chest CT images and to demonstrate the variance of the VLT between the lung and mediastinum/chest wall.nnnSUBJECTS AND METHODSnEighty images were compressed reversibly (as negative control) and irreversibly to 5:1, 10:1, 15:1 and 20:1. Five radiologists determined if the compressed images were distinguishable from their originals in the lung and mediastinum/chest wall. Exact tests for paired proportions were used to compare the readers responses between the reversible and irreversible compressions and between the lung and mediastinum/chest wall.nnnRESULTSnAt reversible, 5:1, 10:1, 15:1, and 20:1 compressions, 0%, 0%, 3-49% (p<.004, for three readers), 69-99% (p<.001, for all readers), and 100% of the 80 image pairs were distinguishable in the lung, respectively; and 0%, 0%, 74-100% (p<.001, for all readers), 100%, and 100% were distinguishable in the mediastinum/chest wall, respectively. The image pairs were less frequently distinguishable in the lung than in the mediastinum/chest wall at 10:1 (p<.001, for all readers) and 15:1 (p<.001, for two readers). In 321 image comparisons, the image pairs were indistinguishable in the lung but distinguishable in the mediastinum/chest wall, whereas there was no instance of the opposite.nnnCONCLUSIONnFor JPEG2000 compression of chest CT images, the VLT is between 5:1 and 10:1. The lung is more tolerant to the compression than the mediastinum/chest wall.

Tuberculous Stenosis of the Left Main Bronchus: Results of Treatment with Balloons and Metallic Stents☆

PURPOSEnTo assess the results of treatment with balloon dilation and metallic Z stents in patients with tuberculous stenosis of the left main bronchus.nnnMATERIALS AND METHODSnNineteen patients with tuberculous stenosis of the left main bronchus were treated with balloon (n = 15) and self-expanding metallic Z stents (n = 4). Respiratory status and pulmonary function tests were followed up for 2-90 months.nnnRESULTSnIn the balloon group, improvements in dyspnea occurred in 73% (11 of 15 patients) immediately, 73% after 1 month, 73% after 6 months, 64% after 1 year, 64% after 3 years, and 42% after 6 years (Kaplan-Meier method). Improvement of pulmonary function (FEV1 or FVC) was achieved in 62% (eight of 13) after 1 year. In the stent group, immediate improvements of dyspnea or pulmonary function occurred in all patients. However, fracture of the stents occurred in two patients, at 4 and 18 months, respectively. Occlusion of the lumen of the stent by granulation tissue occurred in another at 18 months.nnnCONCLUSIONnBalloon dilation can be an effective method for the treatment of tuberculous stenosis of the main bronchus. Metallic Z stents should be used cautiously because of their problems of mechanical durability and overgrowth of granulation tissue.

Computed tomography diagnosis of acute appendicitis: advantages of reviewing thin-section datasets using sliding slab average intensity projection technique.

Objectives:We sought to compare sliding slab mode and standard stack mode in the computed tomography (CT) diagnosis of acute appendicitis. Materials and Methods:Contrast-enhanced CT was performed in 85 patients, 35 of whom had appendicitis. Four readers retrospectively reviewed 5-mm thick transverse sections (4-mm increment) using the stack mode and 2-mm thick sections (1-mm increment) with the sliding slab, average intensity projection. The sliding slab mode started with a 5-mm thick transverse slab, but the readers were encouraged to change the viewing angle and the slab thickness. Results:In sliding slab mode, the readers changed the viewing angle in 89 of 340 observations (24%) and decreased the slab thickness in 26 observations (8%). Although the receiver operating characteristic analysis did not show a significant difference (P = 0.18), the sliding slab mode enhanced the pooled sensitivity (93.6% vs. 98.6%, P = 0.02), specificity (92.0% vs. 97.5%, P = 0.01), and mean confidence for the diagnosis (P < 0.001) or exclusion (P = 0.002) of acute appendicitis; reduced inconclusive interpretations (5.6% vs. 1.8%, P = 0.01); and visualized the appendix more clearly (P < 0.001). Conclusions:Compared with the stack mode, the sliding slab mode enhances diagnostic confidence and more clearly visualizes the appendix.

Is There a Role for FDG PET in the Management of Lung Cancer Manifesting Predominantly as Ground-Glass Opacity?

OBJECTIVEnThe purposes of our study were to evaluate 18F-FDG PET findings of ground-glass opacity (GGO) nodules and to determine the value of FDG PET for the preoperative staging of lung cancer manifesting predominantly as GGO.nnnMATERIALS AND METHODSnEighty-nine patients (46 men and 43 women; mean [±SD] age, 62.4±7.2 years [range, 33-81 years] and 61.7±6.7 years [range, 34-75 years], respectively) with 134 GGO nodules (56 single and 78 multiple) who underwent CT and FDG PET before surgery were included. CT and PET findings were assessed in terms of lesion size, GGO percentage, multiplicity, and maximum standardized uptake value (SUVmax). SUVmax was correlated with lesion size and GGO percentage using linear regression. The SUVmax and hypermetabolism rates of solitary and multiple GGO nodules were compared using the Student t test or Fisher exact test. Lymph node and distant organ metastasis staging by FDG PET were correlated with histopathologic findings.nnnRESULTSnSUVmax was positively correlated with lesion size (mean, 14.5 mm; range, 5-37 mm) (r=0.6705; p<0.0001) and was negatively correlated with GGO percentage (mean, 77%; range, 50-100%) (r=-0.7465; p<0.0001). Solitary nodules showed higher hypermetabolism rates (73% [41/56]) than did multiple nodules (27% [21/78]) (p=0.0001), but SUVmax was not significantly different between solitary and multiple nodules. There was no true-positive interpretation of nodal or distant metastasis from GGO nodules by FDG PET.nnnCONCLUSIONnFDG PET showed no clear advantage for the staging of lung cancer with predominant GGO because of the low incidences of nodal and distant metastasis.

Association of blood glucose at admission with outcomes in patients treated with therapeutic hypothermia after cardiac arrest

BACKGROUNDnIt is well known that hyperglycemia is associated with poor outcomes in critically ill patients. We investigated the association between blood glucose level at admission and the outcomes of patients treated with therapeutic hypothermia (TH) after cardiac arrest.nnnMETHODSnA total of 883 cardiac arrest patients who were treated with TH were analyzed from the Korean Hypothermia Network retrospective registry. We examined the association of blood glucose at admission with survival and neurologic outcomes at hospital discharge. Favorable neurologic outcomes were defined as Cerebral Performance Category scores of 1 and 2.nnnRESULTSnThe mean age of the sample was 56.7 ± 16.2 years, 69.5% of subjects were male, and the mean blood glucose at admission was 14.1 ± 7.0 mmol/L. After adjustment for sex, age, history of diabetes mellitus, hypertension, renal disease and stroke, time from arrest to return of spontaneous circulation, initial rhythm, witness status, bystander cardiopulmonary resuscitation, cause of arrest, and cumulative dose of adrenaline, the associations between glucose and outcomes were as follows: for favorable neurologic outcomes, an odds ratio of 0.955 (95% confidence interval, 0.918-0.994); and for survival, an odds ratio of 0.974 (95% confidence interval, 0.952-0.996).nnnCONCLUSIONnThese results show that blood glucose level at admission is associated with survival and favorable neurologic outcomes at hospital discharge in patients treated with TH after cardiac arrest. Blood glucose level at admission could be a surrogate marker of ischemic insult severity during cardiac arrest. However, randomized, controlled evidence is needed to address the significance of tight glucose control during TH after cardiac arrest.