Gadolinium-Enhanced Magnetic Resonance Imaging of Atherosclerotic Plaques in Comparison with Histopathology: An In Vivo Study in Aorta of Rabbits

PURPOSE: We sought to evaluate enhancement of plaque with gadolinium-based contrast agent by magnetic resonance imaging (MRI) in comparison with histopathology, namely lipid-rich and macrophage-rich components that were two representative characteristics of plaque vulnerability using atherosclerotic rabbit aorta in order to determine which histopathologic component is relevant to the enhancement. MATERIALS AND METHODS: New Zealand white rabbit (n=4, weight 3.0 to 3.5 kg, all male) was used for animal model of atherosclerosis. Atherosclerotic aortic lesions were induced by high-cholesterol diet and double balloon injury. T1-weight axial images were acquired before and after gadolinium-based contrast agent using a 3-T MRI. MR images and the matched histopathological sections (n=35) were divided into 4 quadrants or 3 (n=130). Enhancement ratio (ER, ER=SIpost/SIpre) on MRI was calculated for each quadrant and compared with histopathology in regard to lipid-rich and macrophage-rich areas. RESULTS: Lipid-rich quadrants were 72 and fibrous quadrants were 58. The number of quadrants which had macrophage-rich areas was 105 and that of quadrants which did not have macrophage-rich areas was 25. ER was significantly higher in lipid-rich quadrants than in fibrous quadrants (mean ER 2.25+/-0.41 vs. 2.72+/-0.65, p=0.013). ER poorly correlated with macrophage-rich areas when lipid-component was controlled (correlation coefficient -0.203, p=0.236). CONCLUSION: Lipid-rich plaques showed stronger enhancement than fibrous plaques using a standard gadolinium-based extracellular contrast agent. Macrophage infiltration did not correlate with degree of enhancement. Further study is warranted that account for optimal time of imaging after contrast injection using various plaque models from early to advanced stages and all possible parameters associated with contrast enhancement.

Early Changes of Left Ventricular Geometry and Function after Surgical Ventricular Restoration and Mitral Valve Annuloplasty: Magnetic Resonance Imaging

PURPOSE: We sought to determine the early change of ventricular geometry and function after concomitant surgeries of modified Dor procedure and mitral valve annuloplasty by using magnetic resonance imaging. MATERIALS AND METHODS: We enrolled 21 patients with dilated heart failure who underwent modified Dor procedure (n=8), mitral valve annuloplasty (n=6), or both surgeries (n=7). Cine MRI was used to assess left ventricular dimensions and function before and after surgery. We measured the left ventricular end-diastolic and end-systolic volumes and the dimensions of the left ventricular long-axis and short-axis. Left ventricular stroke volume, ejection fraction, and sphericity index were calculated from these measurements. These parameters were analyzed and compared between three different surgery groups to explain the combined effect of the concomitant surgeries. RESULTS: MRI was performed within average 12 +/- 15 days (range 1-58 days) before and 38 +/- 50 days (range 7- 231 days) after the surgery. The patients who underwent concomitant surgeries had more profound enlargement of left ventricle and decreased contractility prior to surgery than those in the patients who underwent single surgical procedure. Left ventricular end-diastolic volume and endsystolic volume significantly decreased in all patients regardless of surgery type after surgery. Ejection fraction significantly increased only in the patients who got modified Dor procedure without mitral valve annuloplasty (25.4% to 40.7%). Sphericity index increased in patients with modified Dor procedure but decreased in patients with mitral valve annuloplasty (0.65 to 0.78 vs. 0.75 to 0.65). In the patients who underwent concomitant surgeries showed no significant change in sphericity index after surgery. CONCLUSION: The early change of the left ventricular geometry and function after the concomitant surgeries with modified Dor procedure and mitral valve annuloplasty in patients with dilated heart failure includes a marked reduction in left ventricular volume and in stroke volume. The shape of the left ventricle does not change because the effect of sphericity index decrease from mitral valve annuloplasty is counteracted by the effect of sphericity index increase from modified Dor procedure. Improvement of left ventricular ejection fraction is not the early change after the concomitant surgeries.

Magnetic Resonance Imaging of Transient Left Ventricular Apical Ballooning Related to Emotional Stress: a Case Report

Transient left ventricular apical ballooning is characterized by transient wall motion abnormalities involving the left ventricular apex and mid-ventricle in the absence of coronary arterial occlusion. A 66-year-old woman presented to the emergency department with chest pain that mimicked acute myocardial infarction. An aortogram showed akinesis from the mid to apical left ventricle with sparing of the basal segments. Four days later, she underwent MRI, which demonstrated characteristic apical contractile dysfunction, the same as the aortogram, without evidence of myocardial infarction on the MRI. Two weeks later, her symptoms were resolved and follow-up echocardiography showed normal ventricular function.

Noninvasive Assessment of In-Stent Restenosis of the Coronary Artery with Using 16-Slice Computed Tomography

PURPOSE: We strove to evaluate in-stent restenosis of the coronary artery by measuring the in-stent CT attenuation with using 16-multislice CT. MATERIALS AND METHODS: We analyzed the coronary CT angiography, with using 16-slice CT, in 45 stents of 30 patients. The CT attenuation was measured in the lumen of the stented segments and in the lumen of the segment proximal to the stents, and this attenuation was compared with each other. The CT attenuation difference between them was analyzed in relation to the presence of significant in-stent restenosis. Conventional coronary angiography was used as a standard of reference for in-stent restenosis. RESULTS: 12 stents in 12 patients revealed significant restenosis on the conventional coronary angiography. In 6 (50%) of them, the CT attenuation value of the in-stent lumen was lower than that of the proximal segments (373.8 HU vs. 497.1 HU, respectively, p=0.77). In the other 6 stents, a small stent diameter (n=3) and adjacent severe calcification (n=2) accounted for the higher CT attenuation value of the in-stent lumen. In all the stents without significant restenosis, the CT attenuation values of the in-stent lumens were higher than those of their proximal segments. CONCLUSION: The measurement of CT attenuation with using 16-slice CT at the in-stent lumen as compared to the attenuation of the proximal segment provides an objective, confident method for the diagnosis of in-stent restenosis.

Noninvasive Follow-Up of Coronary Artery Bypass Graft Patency Using Multi-Slice Computed Tomography

PURPOSE: We wanted to evaluate the utility of multi-slice computerized tomography (MSCT) for assessing coronary artery bypass graft patency and/or occlusion. MATERIALS AND METHODS: For 24 patients, both conventional angiography and CT angiography with 4-MSCT were performed within seven days of one another in order to evaluate the accuracy of MSCT with regard to graft patency and/or occlusion. A follow-up CT angiogram was performed in patients with and without symptoms (n=11, n=34, respectively) with 4- or 16-MSCT. We retrospectively compared the results of MSCT to those of conventional coronary graft angiography. RESULTS: Sixty-five grafts were evaluated for the accuracy of MSCT. Six of those 65 were occluded. The sensitivity, specificity, positive predictive value and negative predictive values of MSCT for the diagnosis of graft occlusion were 100% (6/6), 98% (58/59), 86% (6/7) and 100% (58/58), respectively. Patency could not be determined by angiography in two grafts; however, the grafts proved to be patent on MSCT. On follow-up, new graft occlusions in the asymptomatic patients were detected by MSCT in 8.2% of the previously patent grafts at the two years post-op, and in 15.2% at the three years post-op. CONCLUSION: MSCT is a practical and accurate noninvasive diagnostic tool for following up coronary artery bypass grafts.

Feasibility and Diagnostic Accuracy of Whole Heart Coronary MR Angiography Using Free-Breathing 3D Balanced Turbo-Field-Echo with SENSE and the Half-Fourier Acquisition Technique

OBJECTIVE: We wanted to assess the feasibility and diagnostic accuracy of whole heart coronary magnetic resonance angiography (MRA) with using 3D balanced turbo-field-echo (b-TFE) with SENSE and the half-Fourier acquisition technique for identifying stenoses of the coronary artery. MATERIALS AND METHODS: Twenty-one patients who underwent both whole heart coronary MRA examinations and conventional catheter coronary angiography examinations were enrolled in the study. The whole heart coronary MRA images were acquired using a navigator gated 3D b-TFE sequence with SENSE and the half-Fourier acquisition technique to reduce the acquisition time. The imaging slab covered the whole heart (80 contiguous slices with a reconstructed slice thickness of 1.5 mm) along the transverse axis. The quality of the images was evaluated by using a 5-point scale (0 - uninterpretable, 1 - poor, 2 - fair, 3 - good, 4 - excellent). Ten coronary segments of the heart were evaluated in each case; the left main coronary artery (LM), and the proximal, middle and distal segments of the left anterior descending (LAD), the left circumflex (LCX) and the right coronary artery (RCA). The diagnostic accuracy of whole heart coronary MRA for detecting significant coronary artery stenosis was determined on the segment-by-segment basis, and it was compared with the results obtained by conventional catheter angiography, which is the gold standard. RESULTS: The mean image quality was 3.7 in the LM, 3.2 in the LAD, 2.5 in the LCX, and 3.3 in the RCA, respectively (the overall image quality was 3.0+/-0.1). 168 (84%) of the 201 segments had an acceptable image quality (> or = grade 2). The sensitivity, specificity, accuracy, negative predictive value and positive predictive value of the whole heart coronary MRA images for detecting significant stenosis were 81.3%, 92.1%, 91.1%, 97.9%, and 52.0%, respectively. The mean coronary MRA acquisition time was 9 min 22 sec (+/-125 sec). CONCLUSION: Whole heart coronary MRA is a feasible technique, and it has good potential to evaluate the major portions of the coronary arteries with an acceptable image quality within a reasonable scan time.

The Utility of Multi-detector Row Spiral CT for Detection of Coronary Artery Stenoses

Contrast-enhanced multi-detector row spiral computed tomography (MDCT) was introduced as a promising noninvasive method for vascular imaging. This study examined the accuracy of this technique for detecting significant coronary artery stenoses. Both MDCT (Sensation 16, Siemens, Germany, 12 x 0.75 mm collimation and 0.42 sec rotation speed, 120 kV, 500 effective mA, and 2.7 mm/rotation table-feed) and invasive coronary angiography (CAG) were performed on 61 patients (mean age 59.2 +/- 10, 44 men) who were suspected of having coronary artery disease. All patients were treated with atenolol (25 - 50 mg) prior to imaging and the heart rate was maintained below 65 beats per minutes during image acquisition. The images were reconstructed in the diastole around TI - 400 ms with a 0.5 mm increment and a 1.0 mm thickness. All coronary arteries with a diameter of 2.0 mm or more were assessed for the presence of a stenosis (> 50% luminal narrowing). Two independent radiologists who were unaware of the results of the invasive CAG evaluated the MDCT data, and the results were compared with those from the invasive CAG (interval 1- 27, mean 11 days). An evaluation of the CT coronary angiogram (CTCA) was possible in 58 of the 61 patients (95%). Image acquisition of the major coronary arteries including the left main trunk was available in 229 out of 244 arteries. Invasive CAG showed that 35 out of 58 patients had significant coronary artery stenoses by. patient analysis of those who could be evaluated showed that CT coronary angiography correctly classified 30 out of 35 patients as having at least 1 coronary stenosis (sensitivity 85.7%, specificity 91.3%, positive predictive value 93.8%, negative predictive value 80.8%). By analyzing each coronary artery, CAG found 62 stenotic coronary arteries in the 229 coronary arteries that could be evaluated. MDCT correctly detected 50 out of 62 stenotic coronary arteries and an absence of stenosis was correctly identified in 156 out of 167 normal coronary arteries (sensitivity 80.6%, specificity 93.4%, positive predictive value 81.9%, negative predictive value 92.8%). The non-invasive technique of MDCT for examining the coronary artery appears to be a useful method for detecting coronary artery stenoses with a high accuracy particularly with the proximal portion and large arteries.

Multiple Cavitary Pulmonary Metastases from Cholangiocarcinoma / 결핵

Because a cavitary pulmonary metastasis is rare, it may not be readily identified. However, various types of cancers can metastasize to the lung in the form of cavities. We report a case of a multiple cavitary metastases to the lung from a cholangiocarcinoma in a 60-year-old man. He complained of generalized weakness and a poor oral intake for 2 months. The plain chest radiography and the chest computed tomography showed multiple small thick-walled cavities and nodules the both lungs. A bronchoscopic examination revealed a focal irregularly elevated surface of the mucosa at the orifice of the superior segment of the right lower lobe and the biopsy demonstrated an infiltrative metastatic adenocarcinoma. The abdomen-pelvis computed tomography showed an ill-marginated and irregularly low-dense area in the right lobe of the liver and a diffuse dilatation of the peripheral intrahepatic bile ducts. The esophagogastroscopy and colonoscopy showed no abnormal findings. It was concluded that the cholangiocarcinoma of the liver metastasized to the lung in the form of cavities. Thereafter, the patient underwent six cycles of the systemic chemotherapy with gemcitabine and cisplatin, and the follow-up imaging studies showed a partial response.

Multidetector Row Computed Tomography: 'Principles and Clinical Applications'

The computed tomography (CT) technology has recently leaped with the advent of the multidetector row technique since the introduction of spiral CT. The most important advantages of multidetector spiral CT (MDCT) are its rapid scan speed and the increased zaxis spatial resolution. MDCT permits selection of high resolution for isometric imaging in any imaging planes, long coverage of study volume, or decreased scan time for clinical purposes and needs. The most widely applied clinical indication of MDCT is CT angiography. MDCT makes a dynamic study or multiphase study easier and more reliable. Combination of isometric imaging in any anatomic planes, CT angiography, multiphase dynamic study, 2or 3dimensional image reconstruction has made radiologic diagnoses more accurate and has provided more useful information for preoperative surgical design and educational purposes. The combined increase of temporal resolution (200 msec) opens the era of cardiac imaging. With its inherent contrast resolution, coronary CT angiogram can reveal atherosclerotic changes of the arterial wall as well as the degree of luminal narrowing. MDCT has provided new opportunities for medical imaging and will expand rapidly with further clinical applications.

Evaluation of the Post-Shunt Status with Electron Beam Computed Tomography in Cyanotic Congenital Heart Disease

The assessment of the accuracy of Electron Beam Computed Tomography (EBCT) for the follow-up of pulmonary vascular system after the shunt operation in cyanotic congenital heart diseases was purpose of the study. The study group consists of 16 consecutive patients with cyanotic congenital heart disease who had Blalock-Taussig (BT) shunt (n=7), bi- directional cavo-pulmonary shunt (BCPS, n=7) and unifocalization (n=2). EBT images were obtained on systolic phase under EKG gating and after intravenous administration of contrast agent. We evaluated the shunt patency, anatomy of intrapericardial pulmonary artery, parenchymal pulmonary vessels and background lung attenuation for the pulmonary blood flow, and the presence of systemic arterial and venous collaterals. Angiography (n=12) and echocardiography (n=16) were used as the gold standards. EBCT was consistent with angiogram in detecting the shunt patency and in depicting the anatomy of the intrapericardial pulmonary artery. Occlusion of the BT shunts was not detected in 2 patients by echocardiography. Diffuse or focally decreased pulmonary flow on EBCT in 8 patients was consistent with the pulmonary hemodynamics pattern revealed by cardiac catheterization. Uneven attenuation between lobes was related with multifocal supply of pulmonary flow or occlusion of lobar pulmonary arteries. Systemic collateral arteries were observed in 5 at the corresponding site of the decreased pulmonary flow. Systemic venous collaterals seen in all patients following BCPS were eventually draining to the inferior vena cava in 5 and to the left atrium in 2. EBCT provided accurate information of the pulmonary vascular system after shunt and has unique advantage over echocardiography in assessing patency of BT shunt or unifocalization tubes within the pleural space, the estimation of regional difference in pulmonary hemodynamics, and the detection of systemic collateral vessels. Therefore EBCT may provide useful information about the timing of definitive correction and the need for a second shunt or an interventional procedure prior to total repair.

Anger and Coronary Calcification in Individuals with and without Risk Factors of Coronary Artery Disease

The authors investigated the relationship between anger and the calcification of the coronary artery in individuals with and without risk factors for coronary artery disease in Korea. Sixty-one subjects with risk factors of coronary artery disease and 31 subjects without risk factors were enrolled in this study. Electron Beam Computed Tomography was used to measure the calcium level of coronary artery. The anger expression scale was used to measure the anger levels. The anxiety, depression, hostility, and somatization subscales of the symptom checklist-90-revised (SCL-90-R) and the global assessment of recent stress (GARS) scale were used to assess the psychopathology and perceived stress. The logistic regression analysis results showed that only the anger-total score was significantly associated with the coronary calcification regardless of the risk factors. These results suggest that anger plays an important role in the calcification of the coronary artery.

Characterization of the Pulmonary Circulation According to Hemodynamic Changes by Computed Tomography

Increased or decreased pulmonary blood flow (PBF) and an increased pulmonary vascular resistance (PVR), represent common and important change in pulmonary hemodynamics. In this study, we constructed 3 hemodynamic models in 5 dogs, that is, an increased and a decreased PBF model, and an increased PVR model. A CT perfusion scan was performed in each hemodynamic model. Perfusion parameters including blood flow (BF), blood volume (BV), mean transit time (MTT), and maximal slope (MS) were calculated automatically by specialized software and analyzed for changes according to hemodynamic status. In terms of the normal state, blood flow was affected by gravity and dependent area showed higher BF and BV and lower MS and MTT than the non-dependent area. The decreased PBF model showed a significant increase in BF and MS (p=0.046, 0.005) but no significant change in BV (p > 0.05), and a slight elongation of MTT (p > 0.05) versus the normal state. The increased PBF model showed a slightly increased BV and a slightly decreased MTT (p > 0.05). The increased PVR model showed significant reduction in BF, BV, and MS (p 0.05). However, it was noticeable that the distribution of MTT with respect to gravity in the normal lung was completely reversed in the increased PVR model. In conclusion, based on our understanding of perfusion characteristic in normal state, abnormal regional hemodynamic changes in the lung can be detected and evaluated. Predicting changes in pulmonary vascular resistance should be possible by a thorough analysis of CT perfusion parameters.

High Resolution CT Findings of Pseudoalveolar Sarcoidosis

PURPOSE: To determine the specific high-resolution CT features of sarcoidosis in which the observed pattern is predominantly pseudoalveolar. MATERIALS AND METHODS: We retrospectively reviewed the HRCT findings in 15 cases in which chest radiography demonstrated pseudoalveolar consolidation. In all 15, sarcoidosis was pathologically proven. The distribution and characterization of the following CT features was meticulously scrutinized: distribution and characterization of pseudoalveolar lesions, air-bronchograms, micronodules, thickening of bronchovascular bundles and interlobular septa, lung distortion, ground-glass opacities and combined hilar and mediastinal lymphadenopathy. Follow-up CT scans were available in three cases after corticosteroid administration. RESULTS: Between one and 12 (mean, 5.6) pseudoalveolar lesions appeared as dense homogeneous or inhomogeneous opacities 1-4.5 cm in diameter and with an irregular margin located either at the lung periphery adjacent to the pleural surface or along the bronchovascular bundles, with mainly bilateral distribution (n=14, 93%). An air-bronchogram was observed in ten cases. Micronodules were observed at the periphery of the lesion or surrounding lung, which along with a thickened bronchovascular bundle was a consistent feature in all cases. Additional CT features included hilar and mediastinal lymphadenopathy (n=14, 93%), thickened interlobular septa (n=12, 80%), and ground-glass opacity (n=10, 67%). Lung distortion was noted in only one case (7%). After steroid administration pseudoalveolar lesions decreased in number and size in all three cases in which follow-up CT was available. CONCLUSION: The consistent HRCT features of pseudoalveolar sarcoidosis are bilateral multifocal dense homogenous or inhomogenous opacity and an irregular margin located either at the lung periphery adjacent to the pleural surface or along the bronchovascular bundles. Micronodules are present at the periphery of the lesion or surrounding lung. The features are reversible at steroid administration.

Histologic Changes of Pulmonary Arteries in Congenital Heart Disease with Left-to-Right Shunt (Part 1): Correlated with Preoperative Pulmonary Hemodynamics. Emphasizing the Significance of Pulmonary Arterial Concentration

The hemodynamic findings related to the histologic changes in the small pulmonary arteries in congenital heart disease were analyzed with a left-to-right shunt. A lung biopsy was performed during the repair because of pulmonary arterial (PA) hypertension (mean PA pressure > or = 15 mmHg) in 38 patients. There were 13 patients whose age ranged from 2 years to 25 years old. A preoperative cardiac catheterization was performed to locate the site of the defect and to determine the preoperative hemodynamic findings. Among them, 29 patients had pulmonary vascular resistance (PVR) > 2.5 unit/m2. The lung biopsy specimens were investigated microscopically for the Heath- Edward grade, morphometric analysis of medial wall thickness (MWT) and the rate of the decrease in the pulmonary arteriolar concentration (PAC) obtained by the alvoelo-arterial ratio divided by patients' age. All patients were in the Heath-Edward grade I to III (29 patients in grade I). This grade correlated with the MWT, but did not correlate with a decrease in the PAC. The MWT and the rate of the decrease in the PAC did not accompany each other, but either one had the tendency dominate the pattern in individual patients. The MWT had a close correlation with the mean PA pressure and PVR, and an even closer correlation in patients with a high PVR and those older than 2 years of age. The rate of the decreased in the PAC showed a weak correlation with the shunt volume in patients over 2 years of age or with a large shunt. In the high flow group (PVR 2.0, n=14) the MWT was significantly thinner and the rate of the decrease in the PAC was significantly higher than the high resistance group (PVR > 2.5 unit/m2, Qp/Qs2 < 2.0, n=13). The rate of the decrease in the PAC correlated with the patients' age, but the MWT did not. The lung biopsy results in patients who had both left-to-right shunts and pulmonary hypertension showed that the rate of the decrease in the PAC was weakly related to the shunt volume and the MWT was related to the PA pressure and PVR. Either an increased MWT or the rate of the decrease in the PAC tended to dominate. These phenomena were prominent in patients older than 2 in whom a wide range of individual variations were noted in the morphometric pattern. The medial hypertrophy and the rate of the decrease in the PAC may be induced by different stimuli or that medial hypertrophy may play a role in preventing PAC decrease.

Histologic Changes of Pulmonary Arteries in Congenital Heart Disease with Left-to-Right Shunt (Part 2): Emphasis on the Significance of Pulmonary Arterial Concentration in the Correlation with Pulmonary Hemodynamics after Repair Ed- The Above is An Altern

We performed this study to assess the correlation of residual pulmonary hypertension in the immediate postoperative period with that in the late follow-up period, to assess the histologic changes of pulmonary arteries (PA) at the time of repair for patients with congenital heart disease consisting of left-to-right shunt, and to clarify the role of lung biopsy in determining the operability and reversibility of pulmonary vascular changes. Lung biopsy was performed during repair in 38 patients, with a wide range of age, who had congenital left to right shunt and pulmonary hypertension. All were Heath-Edward grade III or less. Morphometric study included measurement of medial wall thickness (MWT) and decrease rate of pulmonary arterial concentration (PAC). Mean PA pressure in the immediate postoperative period was measured in all 38 patients. Follow-up cardiac catheterization was performed in 15 patients (average 3.8 years after repair). At operation, 5 patients of this late follow-up group were under 2 years of age and the other 10 were 2 or more. During catheterization, pulmonary hemodynamic reaction was observed both under room air inhalation and after inhalation of hypoxic gas FiO2 0.15. Mean PA pressure and pulmonary vascular resistance (PVR) in the immediate postoperative period had a significant correlation with PA pressure and PVR values before the operation, but not with morphometry, Heath-Edward grade, or with pulmonary hemodynamics in late follow-up. During the late follow-up study, 5 of the 15 patients had pulmonary hypertension (defined as mean PA pressure > or = 15 mmHg) under room air inhalation, and PA hypertension was induced in 4 additional patients after hypoxic gas inhalation. There was no incidence of PA pressure or PVR values registering above the preoperative level. The degree of PA hypertension showed a correlation with the rate of PAC decrease and also with patients' age-at-operation. Multiple regression analysis showed that both the rate of PAC decrease and the age-at-operation contributed significantly to the degree of PA hypertension. Some of the patients over age 2 had a decreased rate of PAC above the regression line, which none of the patients under age 2 experienced. In patients with Heath-Edward grade III or less, residual pulmonary hypertension in the immediate postoperative period was not correlated with histology, but in late follow-up, it was with PAC and the age-at-operation. Therefore, a decrease of PAC is assumed to be a totally or partially irreversible pulmonary vascular change depending on the patient's age-at-operation, while medial hypertrophy is thought to be a reversible pulmonary vascular change. Lung biopsy could play an important role in determining the reversibility of pulmonary vascular obstruction, particularly in patients older than 2 years. Ed- re highlights above: such hyphenation is optional, but if used then it should be applied consistently throughout the paper. As 3 of the 4 entries in the abstract use it, I have maintained it consistently below.

Measurement of Perfusion of Pulmonary Nodules by Electron Beam Tomography

PURPOSE: To investigate the perfusion of pulmonary nodules and the flow pattern revealed by electron beam tomography (EBT), and to evaluate their usefulness in the differential diagnosis of pulmonary nodules. MATERIALS AND METHODS: A prospective perfusion study involving 28 nodules in 23 men and five women (mean age, 57 years) was performed using EBT with the multislice flow mode. There were four phases. Precontrast density (Hounsfield units, HU) in phase 0; perfusion, peak HU and time to peak in phase 1; and mean HU and percentage decrease of HU to peak HU of phase 1 in phases 2 and 3 were measured and compared according to the diagnosis. RESULTS: Malignancy was diagnased in 19 cases [primary lung cancer (n=14); metastatic nodules (n=5)], while nine nodules were benign. Perfusion was significantly higher in malignant nodules than in benign (p<0.001) and a higher mean delay 1 HU (p<0.05) and a significantly short time to peak (p<0.05) were recorded in malignant nodules. In primary lung cancer cases, perfusion was significantly high compared with benign nodules (p<0.001), and a mean delay 1 HU was observed (p<0.05). There was no significant difference in perfusion between primary lung cancer and metastasis. CONCLUSION: Perfusion and flow pattern data measured by EBT can provide the useful information for differentiation between malignant and benign pulmonary nodules.

Pulmonary Inflammatory Pseudotumor: A report of 28 cases

BACKGROUND: Pulmonary inflammatory pseudotumor is an uncommon benign lesion of the lung. In Korea, most literature of the pulmonary inflammatory pseudotumor was case reports. METHODS: We collected 28 cases of pulmonary inflammatory pseudotumor in Korea. This collective series included 4 cases from our hospital and 24 cases were reviewed from the literature since 1977. The analysis involved the age, sex, chief complaint, hematologic examination, size and location of the lesion, cavity formation, presence of calcification and treatment method. RESULTS: Male was more prevalent (81.5%) than female and mean age was 37.9 years old (6~63 yrs). Chief complaints were cough (44.4%), chest pain (29.6%), fever (22.2%), hemoptysis (15%), sputum (15%) and dyspnea (11.1%). There were asymptomatic cases in 11.1%. Hematologic examination revealed normal finding (53.3%) and anemia (20%). The mean size of the lesion was 4.76 cm (1.5~14 cm) and the locations were parenchymal (85.7%), endobronchial (10.7%) and endotracheal (3.6%). Except the endotracheal case, the lesions were in the right (46.4%), the left (42.8%) and bilateral (7.1%). Calcifications (18.5%) and cavitations (11.1%) were present. Diagnostic methods were open thoracotomy (82.1%), bronchoscopy (3.6%), needle aspiration biopsy (7.1%) and core needle gun biopsy (7.1%). Treatments were surgery (85.2%), steroid therapy (7.4%), rigid bronchoscopic removal (3.7%) and observation (3.7%). Postoperative recurrence occurred in only 1 case (4.3%). CONCLUSION: Pulmonary inflammatory pseudotumor was more prevalent in the male, and patients presented with the respiratory symptoms were common. It was necessary to do surgery in most cases for diagnosis and/or treatment.

Coronary Artery Calcium Score using Electron Beam Tomography in the Patients with Acute Obstructive Coronary Arterial Disease : Comparative Study with Asymptomatic High-Risk Group of Atherosclerosis and Chronic Obstructive Coronary Arterial Disease Group

PURPOSE: To compare, through enalysis of the coronary artery calcium (CAC) score and the risk factors for atherosclerosis, the characteristics of acute coronary syndrone between an asymptomatic high-risk group of atherosclerosis patients and a chronic coronary arterial obstructive disease(CAOD) group. MATERIALS AND METHODS: The CAC scores of an asymptomatic high-risk group of atherosclerosis patients (group I, n=284), a chronic CAOD group (group II, n=39) and an acute coronary syndrome group (group III, n=21) were measured by electron beam tomography. Forty-seven patients with CAOD from groups II and III underwent coronary angiography, and we scrutinized age, sex, and risk factors including diabetes mellitus, hypertension, obesity, smoking, hypercholesterolemia and low high-density lipoproteinemia. The numbers of stenotic coronary arterial branches and degree of stenosis revealed by coronary angiography were also recorded. We determined the differences between the three groups in terms of CAC score and the risk factors, the relationship between CAC score and risk factors, and the characteristic features of each type of CAOD group. RESULTS: The mean CAC score of group III (135.1) was not statistically different from that of group I (135.7) or group II (365.8). Among patients aged below 50, the mean CAC score of group III (127.4) was significantly higher than that of group I (6.2), (p=0.006). The mean CAC score at the sixth decade was also significantly different between group I (81.5) and group II (266.9). The mean age of group III (54.2 years) was significantly lower than that of group I (58.1 years) (p=0.047) and of group II (60.1) (p=0.022). There was significant correlation between the number of stenotic coronary arterial branches and log(CAC+1) (p<.01). The square root of the CAC score and the maximal degree of stenosis was also well correlated (p<.01). There was no difference in the mean number of risk factors among the three groups, though the incidence of smoking in group III was significantly higher than in groups I and II. Multiple regression analysis showed that the CAC score was related to age, diabetes mellitus and hypertension in group I, diabetes mellitus only in group II, but no particular factor in group III. CONCLUSION: The CAC score of the acute coronary syndrome group tended to be lower than that of the chronic CAOD group. It appears to be difficult to predict acute coronary syndrome on the basis of CAC alone. Compared with the asymptomatic high-risk group of atherosclerosis patients, the acute coronary syndrome group, whose members are younger and have a higher incidence of smoking, has a relatively high CAC score.

Prevalence of Antibodies to PPD and Lipoarabinomannan of Mycobacterium tuberculosis among Patients with an Indication of Fine Needle Aspiration Biopsy

Recent increase in the incidence of lung cancer often makes it difficult to differentiate between lung cancer and tuberculosis (TB), due to their radiologic similarities. Fine needle aspiration biopsy (FNAB) has been widely employed for the diagnosis of lung cancer and TB, but the diagnostic accuracy of TB is not high enough. As a rapid screening test for tuberculosis, we evaluated serological tests using Mycobacterium tuberculosis PPD and lipoarabinomannan (LAM) antigens. A total of 95 patients with indication of FNAB cytology from initial CT findings were enrolled. 25 patients had TB, 76 thoracic malignancy, and six (7.9%) of the lung cancer patients also had TB, indicating much higher prevalence of TB in thoracic tumor patients. Antibodies to PPD were elevated in 18 (72.0%) of 25 TB patients and in 22 (31.4%) of 70 patients with thoracic malignancy. In contrast, only 3 (4.7%) of 64 healthy controls aged 40 or above were seropositive to PPD antigen. The prevalence of anti-PPD antibodies in thoracic tumor patients was therefore significantly greater than that amongst the healthy controls (p 0.001, chi-square test). However, no significant difference in the prevalence of anti-LAM antibodies was found between study subjects and controls. This study demonstrates that thoracic tumor patients have significantly elevated antibodies to PPD; therefore, high anti-PPD seroreactivity in thoracic tumor patients should be cautiously interpreted. A longitudinal investigation on seropositive thoracic tumor patients is required to determine the role of the serological test for TB in lung cancer patients.

Diagnostic Usefulness of MRI for Pulmonary Hamartoma: CT, MRI and Histopathologic Correlations

PURPOSE: To determine the diagnostic usefulness of MRI in pulmonary hamartoma, and the significant MRI features other than fat or characteristic calcification, both revealed by CT. MATERIALS AND METHODS: We prospectively studied chest MR images in five patients with pulmonary hamartoma. All underwent narrow-collimated CT scanning and conventional MRI, specimen MRI was available in three cases. Pulmonary nodular size, shape and margin and the presence of intratumoral fat density, calcification and a cleft-like structure were determined. At MRI, the presence and signal intensity (SI) of the cleft-like structure, including intratumoral cystic space and SI of the main portion of the tumor, were analyzed and compared with the findings of specimen MRI, and correlated with the histopathologic findings. In three cases, the typical enhancement pattern revealed by post-contrast MRI was also evaluated. RESULTS: Narrow-collimated CT scanning revealed fat density or popcorn-shape calcification in two cases and a cleft-like structure in one. The other two cases showed neither fat nor calcification. At MRI, however, all five cases showed a cleft-like structure, which was especially evident on T2WI. The detectability of this did not vary between conventional and specimen MRI. The cleft-like structure showed varying SI on T1, and T2WI correlated to variable mesenchymal component including with respiratory epithelial cells lining the cleft. Marginal rim enhancement was noted on all three post-contrast MR images, and correlated with the relatively rich vascularity of the tumor's marginal portion. An enhanced cleft-like structure was noted in two cases. CONCLUSION: The presence of a cleft-like structure, especially prominent on T2WI and with variable SI, is a useful MR finding for the diagnosis of pulmonary hamartoma, and marginal rim enhancement is an ancillary diagnostic MR finding. In particular, MRI is a useful diagnostic tool in cases where a simple pulmonary nodule demonstrates neither fat nor calcification.