Venous Malformation in the Anterior Mediastinum.

Venous malformations (VMs) located in the anterior mediastinum are rare. Thus, diagnosis using imaging is often challenging, and they are typically diagnosed only after total tumor resection. Herein, we report a case of VM located in the anterior mediastinum diagnosed using computed tomography (CT) and magnetic resonance imaging (MRI). A 56-year-old woman presented for further evaluation of an anterior mediastinal mass observed during a chest CT. On CT, the mass was observed to have scattered calcifications and early and persistent enhancement with contrast material pooling dorsally in the delayed phase. On MRI, the mass was isointense on T1-weighted imaging and hyperintense on T2-weighted imaging without flow voids. From these images, we suspected the mass to be a VM, but the possibility of an arterial malformation/fistula could not be ruled out. Initially, a contrast material was injected via the arm, but to improve differentiation, it was also injected via the leg. The 4D-CT of the leg indicated no early enhancement of the mass; however, gradual enhancement was observed. This led to a definite diagnosis of VM. As she had no symptoms, we opted for a CT follow-up, and the mass remained stable for one year post-diagnosis. This case report underscores the usefulness of injecting contrast material through the leg in distinguishing VM from AVM/Fs in the anterior mediastinum.

Preliminary Experience of Endovascular Embolization Using N-Butyl Cyanoacrylate for Hemoptysis due to Infectious Pulmonary Artery Pseudoaneurysms via Systemic Arterial Approach.

We report 5 patients with hemoptysis due to infectious pulmonary artery pseudoaneurysm (PAP) treated with endovascular embolization using N-butyl cyanoacrylate (NBCA) injected via bronchial and nonbronchial systemic arterial approaches. Infectious diseases included inactive tuberculosis (n = 3), nontuberculous mycobacteriosis (n = 1), and chronic infection of unknown origin (n = 1). Seven PAPs were detected on selective systemic angiography, and injection of NBCA was performed. Disappearance of all PAPs was confirmed on systemic arteriography after the intervention. In all patients, hemoptysis was stopped without major complications, and it did not recur during the follow-up period (mean, 351 d; range, 285-427 d).

Interventional therapeutic strategy for hemoptysis originating from infectious pulmonary artery pseudoaneurysms.

This study reports 6 cases of hemoptysis originating from infectious pulmonary artery pseudoaneurysms (PAPs). Selective pulmonary angiography revealed PAPs in 5 cases, and segmental pulmonary artery embolization was performed using coils and gelatin sponge particles. Systemic arterial embolization also was performed in 5 cases because of inadequate initial control or for shunts from systemic to pulmonary arteries. At a median follow-up time of 9 months (range, 25 d to 25 mo), no recurrence occurred, although 2 patients died of respiratory failure. Segmental artery embolization combined with systemic artery embolization may be useful in patients with hemoptysis secondary to PAPs.

Mediastinal schwannoma diagnosed preoperatively as a cyst.

Mediastinal schwannomas are sometimes diagnosed as pericardial or bronchogenic cysts, if cystic degeneration is extensive. When mediastinal schwannomas are not diagnosed as primary cardiac tumors, the use of cardiopulmonary bypass in their resection appears to be infrequent. We report the case of a 48-year-old woman who presented with symptoms from a suspected intrapericardial cyst. Multiple diagnostic images revealed a large mass, potentially a proteinaceous or hemorrhagic cyst, in the transverse sinus behind the ascending aorta and against the left main trunk. After complete resection with the use of cardiopulmonary bypass, the mass was identified as a benign extracardiac schwannoma. More than 3 years postoperatively, the patient had no relevant symptoms. We discuss the preoperative diagnosis, the method of resection, and our broad strategy for dealing with such a case.

Intravenous Lobular Capillary Hemangioma Occurring after Needle Insertion during Routine Health Checkup.

Surgery was performed on a 53-year-old male patient with a painful mass in front of the elbow. The mass originally occurred after needle insertion during a routine health checkup and grew in size during a 1-year period. Intravenous tumor with arterio-venous fistula was diagnosed, and it was resected. Histopathological diagnosis of intravenous lobular capillary hemangioma was made. Occurrence of this tumor after a routine health checkup is rare. The etiology of this tumor occurring simultaneously with arteriovenous fistula is discussed.

Resection of an intrapericardial lipoma with nonsustained ventricular tachycardia.

A 35-year-old female presented with nonsustained ventricular tachycardia (NSVT) and a large intrapericardial mass. The mass was attached to the left ventricular wall with a broad stalk. On histopathology, the tumor was diagnosed as a lipoma. Postoperatively, the NSVT disappeared.

Malignant solitary fibrous tumor of the left ventricular epicardium.

Reports describing solitary fibrous tumors of the pericardium are rare. Surgical treatment was performed on a 49-year-old woman with a large pericardial mass. The mass was attached to the left ventricular wall with a broad stalk and was free of the parietal pericardium. It was apparent macroscopically that the tumor had invaded the left ventricular muscle. On histopathology, the tumor was diagnosed as a solitary fibrous tumor with low-grade malignancy.

Two cases of postmyomectomy pseudoaneurysm treated by transarterial embolization.

Pseudoaneurysm resulting from hysteroscopic myomectomy is a rare clinical situation, and interventional radiologists are not traditionally involved in the management. To our knowledge, endovascular treatment of a pseudoaneurysm resulting from hysteroscopic myomectomy has not yet been reported in the English-language literature. Here, two such cases are reported, including one of a woman who later became pregnant. The case is unique because little is known about the influence of unilateral coil embolization of the uterine artery on fertility.

Ectopic cervical thymoma located in the carotid triangle.

Ectopic cervical thymoma is an extremely rare tumor thought to arise from ectopic thymic tissue caused by the aberrant migration of the embryonic thymus. We present the case of a 44-year-old woman with an ectopic cervical thymoma located in the carotid triangle. A computed tomography (CT) scan detected a mass in her right carotid triangle. On an unenhanced scan, the tumor showed homogeneous isodensity compared with muscles, and neither fat nor calcification was detected. A contrast-enhanced CT image obtained during the arterial phase showed intratumoral septa, while an image obtained during the parenchymal phase showed cystic changes within the mass. The patient underwent a surgical resection. A histological study enabled a diagnosis of type AB thymoma in which foci with the features of type A thymoma are admixed with foci rich in lymphocytes. This subtype is a benign tumor with a good prognosis. Ectopic cervical thymoma should be included in the differential diagnosis of solid masses located in the carotid triangle when the CT findings are typical of a thymoma.

Fast scanning tomosynthesis for the detection of pulmonary nodules: diagnostic performance compared with chest radiography, using multidetector-row computed tomography as the reference.

OBJECTIVES: : To evaluate the diagnostic performance of fast scanning tomosynthesis in comparison with that of chest radiography for the detection of pulmonary nodules, using multidetector-row computed tomography (MDCT) as the reference, and to assess the association of the true-positive fraction (TPF) with the size, CT attenuation value, and location of the nodules. MATERIALS AND METHODS: : The institutional review board approved this study, and written informed consent was obtained from all patients. Fifty-seven patients with and 59 without pulmonary nodules underwent chest MDCT, fast scanning tomosynthesis, and radiography. The images of tomosynthesis and radiography were randomly read by 3 blinded radiologists; MDCT served as the reference standard. Free-response receiver-operating characteristic (FROC) and receiver-operating characteristic (ROC) analyses, Cochran-Armitage trend or Fisher exact test, a conditional logistic regression model, and McNemar test were used. RESULTS: : Both FROC and ROC analyses revealed significantly better performance (P < 0.01) of fast scanning tomosynthesis than radiography for the detection of pulmonary nodules. For fast scanning tomosynthesis, the average TPF and false-positive rate as determined by FROC analysis were 0.80 and 0.10, respectively. For both fast scanning tomosynthesis and radiography, the average TPF increased with increasing nodule size and CT attenuation values, and was lower for subpleural nodules (all P < 0.01). CONCLUSIONS: : The diagnostic performance of fast scanning tomosynthesis for the detection of pulmonary nodules was significantly superior to that of radiography. The TPF was affected by the size, CT attenuation value, and location of the nodule, in both fast scanning tomosynthesis and radiography.

Incidence of tracheobronchomalacia associated with pulmonary emphysema: detection with paired inspiratory-expiratory multidetector computed tomography using a low-dose technique.

PURPOSE: The purpose of this study was to evaluate the frequency of tracheobronchomalacia (TBM) associated with pulmonary emphysema with paired inspiratory-expiratory multidetector computed tomography (MDCT) using a low-dose technique. MATERIALS AND METHODS: This study included 56 consecutive patients (55 men, 1 woman; mean age 68.9 years) with pulmonary emphysema who had undergone paired inspiratory-expiratory CT scanning with a low-dose technique (40 mA). All images were retrospectively examined by two thoracic radiologists in a blinded fashion. The diagnosis of TBM was based on the standard criterion of >50% reduction in the cross-sectional area of the tracheobronchial lumen at the end-expiratory phase. A mild TBM criterion of >30% reduction was also reviewed. All patients underwent pulmonary function tests. The relation between the forced expiratory volume in 1 s (FEV(1.0%)) and TBM was statistically analyzed. RESULTS: Four (7.1%) and eight (14.3%) patients were diagnosed as TBM based on the standard and mild criteria, respectively. In four patients, the percentages of luminal narrowing were 63.4% and 51.2%, respectively for tracheomalacia and 59.2% and 62.0%, respectively, for bronchomalacia. The FEV(1.0%) values between patients with and without TBM showed no statistical difference. CONCLUSION: The incidence of TBM associated with pulmonary emphysema was 7.1% with the standard criterion. It is possible that TBM has been underdiagnosed in a number of patients with pulmonary emphysema.

Mediastinal lymph nodes in patients with non-small cell lung cancer: preliminary experience with diffusion-weighted MR imaging.

OBJECTIVES: The purpose of our study was to describe our preliminary experience of evaluating mediastinal lymph node metastases with diffusion-weighted magnetic resonance (MR) imaging in patients with non-small cell lung cancer. MATERIALS AND METHODS: Forty-two consecutive patients with non-small cell lung cancer underwent preoperative diffusion-weighted MR imaging using a non-breath-hold short inversion time inversion recovery-echo planar imaging sequence with a high b value of 1000 s/mm2. An experienced thoracic radiologist prospectively evaluated each study for mediastinal lymph node metastases on a per-patient basis. On diffusion-weighted MR imaging, mediastinal lymph node metastasis was defined as a focus of low signal intensity at the site of a visible lymph node on corresponding T2-weighted image. The MR results were correlated with histopathologic findings. RESULTS: Diffusion-weighted MR imaging demonstrated mediastinal lymph node metastasis in 4 (80%) of 5 patients with pathologically proven metastasis and accurately identified 36 (97%) of 37 patients without mediastinal lymph node metastasis. Thus, 40 (95%) of 42 patients were accurately diagnosed. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of diffusion-weighted MR imaging for mediastinal lymph node metastasis were 80%, 97%, 80%, 97%, and 95%, respectively. CONCLUSIONS: Our preliminary results show that diffusion-weighted MR imaging has a high negative predictive value for excluding mediastinal lymph node metastases from non-small cell lung cancer and has the potential to be a reliable alternative non-invasive imaging method for the preoperative staging of mediastinal lymph node in patients with non-small cell lung cancer.

Architecture of authorization mechanism for medical data sharing on the grid.

Data security is becoming increasingly important as the Grid matures. The advances of the Grid have allowed scientists and researchers to build a data grid where they can share and exchange research-related data and information. In reality, however, these specialists do not benefit enough from this data grid. The reason is that the current Grid does not have sufficiently robust and flexible data security. We investigate a medical data-sharing environment where medical doctors and scientists can securely share clinical and medical research data. We show medical data sharing that takes advantage of PERMIS, or an RBAC-based authorization system that achieves XML element level access control. We also describe the lessons learnt in designing the environment as well as a comparison with other existing authorization mechanisms.

Mixture distribution analysis of a computer assisted diagnostic method for the evaluation of pulmonary nodules on computed tomography scan.

RATIONALE AND OBJECTIVES: To compare the effectiveness of a new computational scheme for pulmonary nodule detection in computed tomography images against human observers. MATERIALS AND METHODS: The study involved evaluation of 81 potential nodules by four radiologists. Each radiologist separately evaluated the potential nodules and provided a confidence level for the presence of pulmonary nodules. Their performance was compared with that of the new computational scheme by mixture distribution analysis. RESULTS: Mixture distribution analysis of the results of the four radiologists demonstrated a relative proportion agreement of 0.84. The kappa statistic was used to compare the agreement of the computational scheme with the results of the four radiologists. A kappa value of .65 (se = .11) was shown to be significantly different from chance (P = .99). CONCLUSION: The new computational scheme correlates well with the radiologists' subjective rankings of pulmonary nodules on computed tomography scans and may prove a useful tool in the evaluation of algorithms for the screening and diagnosis of lung cancer.

Bronchial artery dilatation on MDCT scans of patients with acute pulmonary embolism: comparison with chronic or recurrent pulmonary embolism.

OBJECTIVE: The purpose of our study was to compare the bronchial arteries of patients with acute pulmonary embolism with those of patients with chronic or recurrent pulmonary embolism. MATERIALS AND METHODS: Twenty-seven patients with acute pulmonary embolism and 14 patients with chronic or recurrent pulmonary embolism were retrospectively identified from 700 consecutive patients with suspected pulmonary embolism. The case data for the patients were assessed by two thoracic radiologists whose final judgments were reached by consensus. On the MDCT pulmonary angiograms obtained in these patients, the bronchial arteries were assessed by finding enhancing, small, round or curvilinear structures within the mediastinum and tracing their paths along the bilateral main bronchi. Bronchial arteries with a diameter greater than 1.5 mm were considered to be dilated. RESULTS: The diameters of the bronchial arteries in the group with chronic or recurrent pulmonary embolism were significantly larger than diameters of the bronchial arteries in the group with acute pulmonary embolism (p = 0.0002). Dilatation of bronchial arteries was observed in two of the 27 patients with acute pulmonary embolism and in seven of 14 patients with chronic or recurrent pulmonary embolism. This difference was statistically significant (p = 0.004). No dilated bronchial arteries were seen in patients who had acute pulmonary embolism but had no a history of deep venous thrombosis. CONCLUSION: Acute pulmonary embolism did not appear to cause dilatation of bronchial arteries, whereas chronic or recurrent pulmonary embolism was frequently associated with dilated bronchial arteries. In patients in whom the distinction between acute and chronic or recurrent pulmonary embolism on MDCT pulmonary angiography is clinically unclear and in whom the bronchial arteries are dilated, a diagnosis of chronic or recurrent pulmonary embolism should be favored.

Voxelwise mapping of magnetic resonance ventilation-perfusion ratio in a porcine model by multimodality registration: technical note.

RATIONALE AND OBJECTIVES: The purpose of this study was to demonstrate the construction of voxelwise ventilation-perfusion (V/Q) ratio maps in a porcine model by nonrigidly aligning the respective ventilation and perfusion images using a multimodality registration algorithm. MATERIALS AND METHODS: The first-pass contrast agent technique for a blood flow map and 3He used for ventilation imaging were performed using a normal porcine model. The registered 3He-ventilation image was then aligned to the blood flow map using a multimodality registration algorithm. The voxelwise V/Q ratios were calculated by dividing the registered 3He-ventilation image by the blood flow map. The V/Q ratios were also semi-logarithmically scatter-plotted against the number of voxels. RESULTS: From perfusion magnetic resonance images, a voxel-by-voxel blood flow map was produced. Registered 3He ventilation image was successfully obtained as well as V/Q ratio map. Plots of the V/Q ratios obtained by this registration approach were similar to the logarithmic normal distribution. CONCLUSION: Registration of MR perfusion and ventilation images can potentially enable quantitative evaluation of regional pulmonary function and thus yield deeper insight into the physiology and pathophysiology of the lung.

Characterization of regional pulmonary mechanics from serial magnetic resonance imaging data.

RATIONALE AND OBJECTIVES: The aim of this study was to investigate a method for quantifying lung motion from the registration of successive images in serial magnetic resonance imaging acquisitions during normal respiration. MATERIALS AND METHODS: Estimates of pulmonary motion were obtained by summing the normalized cross-correlation over serially acquired lung images to identify corresponding locations between the images. The estimated motions were modeled as deformations of an elastic body and thus reflect to a first order approximation the true physical behavior of lung parenchyma. The Lagrangian strain, derived from the calculated motion fields, were used to quantify the tissue deformation induced in the lung over the serial acquisition. RESULTS: The method was validated on a magnetic resonance imaging study, for which breath-hold images were acquired of a healthy volunteer at different phases of the respiratory cycle. Regional parenchymal strain was observed to be oriented toward the pulmonary hilum, with strain magnitude maximal at the midcycle of the expiratory phase. CONCLUSION: In vivo magnetic resonance imaging quantification of lung motion holds the potential of providing a new diagnostic dimension in the assessment of pulmonary function, augmenting the information provided by studies of ventilation and perfusion.

Tracheomalacia incidentally detected on CT pulmonary angiography of patients with suspected pulmonary embolism.

OBJECTIVE: The aim of this study was to determine the frequency of tracheomalacia incidentally detected on CT pulmonary angiography in patients with suspected pulmonary embolism. MATERIALS AND METHODS: CT records of 163 consecutive patients imaged with CT pulmonary angiography for suspected pulmonary embolism were retrospectively reviewed at our institution. The patients underwent CT pulmonary angiography with three different types of CT scanners. All images were visually assessed by two thoracic radiologists for excessive collapse of the trachea and the main bronchi. The cross-sectional area of the lumen at the site of maximal collapse of the airway was measured, and the percentage of luminal narrowing was calculated by comparing it with the cross-sectional area of the airway lumen at an adjacent area without collapse. We defined tracheomalacia as a 50% or greater decrease in tracheal lumen. RESULTS: Sixteen (10%) of 163 patients showed evidence of tracheomalacia (seven men, nine women; age range, 41-95 years; mean age, 72 years). The most common presenting symptom was shortness of breath, which was observed in 13 (81%) of 16 patients. Known causes of tracheomalacia were found in 15 (94%) of 16 patients, prior intubation was confirmed in 12 patients, and history of asthma or chronic obstructive pulmonary disease was observed in five patients. CONCLUSION: Tracheomalacia is a relatively common incidental finding on CT pulmonary angiography studies. The central airways, as well as pulmonary vasculature, should be reviewed carefully for clinical interpretation in patients with suspected pulmonary embolism. Paired expiratory-inspiratory CT is recommended if patients present with known causes of tracheomalacia such as prior intubation, chronic obstructive pulmonary disease, or asthma.

2003 AUR Memorial Award. Dynamic expiratory volumetric CT imaging of the central airways: comparison of standard-dose and low-dose techniques.

RATIONALE AND OBJECTIVES: Investigators in this study compared standard-dose and low-dose inspiratory and expiratory computed tomographic (CT) images with regard to their usefulness for measuring the tracheal lumen in patients with or without tracheobronchomalacia (TBM). MATERIALS AND METHODS; Hospital records were reviewed to identify 10 consecutive patients with bronchoscopically proved TBM and 10 control subjects without TBM who underwent paired volumetric inspiratory and dynamic expiratory examinations with multisection CT. A low-dose (40-80 mA) technique was used for dynamic expiratory CT in 14 (70%) of the 20 subjects, and a standard dose (240-280 mA) was used in the remaining six (30%). All images were reviewed in a randomized, blinded fashion by two observers, who measured the tracheal lumen to determine the presence of TBM by consensus. The degree of confidence in measuring the tracheal lumen was graded on a four-point scale from 0(no confidence) to 3 (highest level of confidence), also by consensus of the two observers. Statistical analysis for differences in confidence level was performed with the Mann-Whitney U test. The image noise level was assessed by measuring the standard deviation of the presternal soft tissue, and statistical analysis for differences in noise level was performed with the t test. RESULTS: The level of confidence in tracheal lumen measurement was high, regardless of respiratory phase and dose (inspiratory mean, 2.9; median, 3; range, 2-3; expiratory low-dose mean, 2.6; median, 3; range, 2-3; expiratory standard-dose mean, 2.8; median, 3; range, 2-3). There was no significant difference in confidence level between standard- and low-dose techniques (P = .53). Excessive central airway collapse (expiratory reduction in cross-sectional diameter, > 50%) was seen in all 10 patients with TBM and in none of the control subjects. CONCLUSION: The acquisition of paired inspiratory and dynamic expiratory images with multisection helical CT is a promising method for diagnosing TBM. The low-dose technique performs as well as the standard-dose technique for the dynamic expiratory phase, with a similar degree of confidence for measuring the tracheal lumen.

Pulmonary hilar lymph nodes in lung cancer: assessment with 3D-dynamic contrast-enhanced MR imaging.

PURPOSE: We performed 3D-dynamic MRI on patients with primary lung cancer to identify its usefulness for detecting hilar adenopathy shown at surgery. METHODS AND MATERIALS: 30 consecutive patients with peripheral lung cancer underwent preoperative 3D-dynamic Gd-DTPA-enhanced MRI. Two thoracic radiologists blinded to histopathologic findings reviewed those studies independently for hilar adenopathy visualization. The results were correlated with surgical and histopathologic findings. Interreader agreement for the detection of hilar adenopathy was assessed by means of the kappa statistic. RESULTS: Dynamic MRI demonstrated hilar adenopathy, with or without metastasis revealed at surgery, in all of 15 patients. Adenopathy without metastasis was shown in four patients. Dynamic MRI also revealed metastatic adenopathy in 11 of 12 patients with pathologically proven metastasis. There was only one case with lymph node metastasis that did not have adenopathy either on MRI or even at surgery. The diagnostic accuracy of dynamic MRI for adenopathy with or without metastases revealed at surgery were as follows; sensitivity, 100%; specificity, 100%; positive predictive value, 100%; and negative predictive value, 100%, respectively. The diagnostic accuracy of dynamic MRI for hilar lymph nodes metastasis were as follows; sensitivity, 92%; specificity, 78%; positive predictive value, 73%; and negative predictive value, 93%. Interreader agreement was substantial (kappa=0.73) for detection of hilar adenopathy. CONCLUSION: Hilar adenopathy on 3D-dynamic MRI correlated well with that of surgical finding on patients with primary lung cancer. It may have the potential to make an accurate preoperative evaluation of hilar lymph node metastasis from lung cancer.