Mediastinum In Patients Research Articles

Computer-assisted laparoscopic repair of „upside-down“ stomach with the Da Vinci system

Recently introduced telerobotic surgical systems attempt to elude the inherent limitations of traditional laparoscopic surgery. The first 15 cases were prospectively evaluated. Mixed hiatal and paraesophageal hernias with fixed intrathoracic partial or complete displacement of the stomach were treated using the Da VinciÒ robotic system. Tissue dissection, hiatoplasty and anterior hemifundoplication (Dor) were performed by the telerobotic system. There were no surgical complications. The system broke down in the fourth patient due to software defect. Advantages were seen in terms of the intrathoracic dissection of displaced stomach through a narrow hiatus, intracorporeal suturing due to six degrees of freedom plus grasping. Current lack of the appropriate robotic instruments for abdominal surgery as well as the enormous functional cost of the robotic system are considered to be its main disadvantage at the moment. The continuous evolution and upgrade of the system is quite promising so far. Telerobotic assisted hiatal hernia operation is feasible with many advantages compared to the traditional laparoscopic approach especially during the dissection in the mediastinum in patients with intrathoracic stomach. A prospective randomised trial is performed. Technological evolution will hopefully diminish the current problems and the costs associated with robotic surgery.

MRT der Pulmonalarterien bei Kindern nach arterieller Switch-Operation (ASO) bei Transposition der großen Gefäße (d-TGA)

To determine the value of MRI in postoperative evaluation of patients with arterial-switch-operation (ASO) for d-TGA. 14 consecutive patients with d-TGA and ASO were examined with MRI in addition to ultrasound because the acoustic window in echocardiography was insufficient. Nine patients had a pulmonary-artery-bifurcation anterior to the aortic root (group 1), and five (group 2) laterally (two of them left, three of them right). MRI was performed in six patients as contrast-enhanced MR-angiography, in 8 patients as native examination. Diameters of pulmonary arteries were measured in two perpendicular views at the origin and in two further locations each with a distance of one cm. One patient showed a supravalvular pulmonary artery stenosis with subsequent pulmonary artery aneurysm, which had not been detected in echocardiography. This patient showed only indirect signs of pulmonary artery stenosis in echocardiography. Compared to group 1, pulmonary arteries in group 2 generally had greater diameters. Those pulmonary arteries in Group 2 which cross the mediastinum underneath the aortic arch had lower diameters compared to the pulmonary artery positioned on the other side. In group 1, the left-sided pulmonary artery had lower diameters than the right-sided pulmonary arteries. It seems remarkable that the narrowing of pulmonary arteries is associated with a flattening of the transversal vessel diameter. Narrowing of pulmonary arteries after ASO is associated with oval vessel diameters. Therefore, multiplanar diagnostic methods are necessary. MRI meets this prerequisite and is therefore advantageous to echocardiography in follow-up examinations at patients with ASO for d-TGA. Special attention should be focused on the main pulmonary artery, on the left pulmonary artery in patients with preaortic pulmonary artery bifurcation as well as on the pulmonary artery which crosses the mediastinum in patients with laterally placed pulmonary artery bifurcation. Angiography should only be performed when intervention is planned.

A comparative analysis of positron emission tomography and mediastinoscopy in staging non–small cell lung cancer

Objectives Positron emission tomography has been demonstrated to improve the detection of distant metastases in patients with lung cancer. This study compares the efficacy of PET to mediastinoscopy in mediastinal staging of patients with non–small cell lung cancer. Methods Between May 1995 and May 2000, positron emission tomography was performed on 1988 patients with known or suspected non–small cell lung cancer at Duke University Medical Center. Cervical mediastinoscopy was subsequently performed in patients without demonstrable evidence of distant metastases. The efficacy of mediastinal staging was analyzed by comparing the prospective results of positron emission tomography with the histopathologic results of mediastinoscopy by nodal station. Results In this study 202 patients with non–small cell lung cancer (116 of whom were male) underwent mediastinoscopy after positron emission tomography. Of the 65 patients with positive results of positron emission tomography, only 29 patients had positive results of mediastinoscopy in the corresponding nodal station. Of the 137 patients with negative results of positron emission tomography, 16 patients were demonstrated to have N2 or N3 disease. The sensitivity, specificity, positive and negative predictive values, and accuracy for positron emission tomography were 64.4%, 77.1%, 44.6%, 88.3%, and 74.3%, respectively. Histologic findings in patients with non–small cell lung cancer and false-positive results of mediastinal positron emission tomography included granulomatous inflammation, sinus histiocytosis, and silicosis. Conclusions Positron emission tomography neither confirms nor excludes involvement of the mediastinum in patients with non–small cell lung cancer. Cervical mediastinoscopy with lymph node biopsy remains the criterion standard for mediastinal staging.

Thymic lesions and myasthenia gravis. Diagnosis based on mediastinal imaging and pathological findings

To achieve a better understanding of the role of CT and MR imaging in the study of the mediastinum in patients with myasthenia gravis (MG). Mediastinal CT and MR findings were correlated with the histopathological results in 104 thymectomized MG patients. CT was performed in 104 patients; in 11 of them, MR was also carried out. 44 patients had hyperplasia at histology. On CT, thymic hyperplasia was confirmed in 16 cases, thymoma was diagnosed in 10 and a normal thymus in 18 (sensitivity 36%, specificity 95%). Of 52 patients with thymoma at histology, CT showed thymoma in 46, hyperplasia in 1, and normal thymus in 5. CT showed 88.5% sensitivity and 77% specificity for thymoma. In 10 patients with invasive thymoma, CT was indiscriminate, while invasiveness was detected in 7 cases at MR (70% sensitivity) and at CT in 1 case. Both CT and MR detected tumor recurrence in 5 cases, but the exact localization and degree of invasion were best defined by MR. In MG patients CT is a sensitive, specific and efficient modality for detecting thymoma, but is less so for detecting thymic hyperplasia. MR was shown to be accurate in detecting invasive thymoma both preoperatively and in postoperative follow-up.

Endoscopic ultrasound guided biopsy of mediastinal lesions has a major impact on patient management

Background: A study was undertaken to evaluate the clinical impact of endoscopic ultrasound guided fine needle aspiration biopsy (EUS-FNA) in patients with mediastinal masses suspected of malignancy. Methods: From April...

Outcomes and cost-effectiveness of alternative staging strategies for non-small-cell lung cancer.

To identify the optimal strategy for staging the mediastinum of patients with known non-small-cell lung cancer (NSCLC), stratified by tumor (T) classification. We used a decision-analytic model to compare the health outcomes and cost-effectiveness of three staging strategies: (1) chest computed tomography alone, (2) selective mediastinoscopy, and (3) routine mediastinoscopy. The overall effectiveness and cost of each strategy was a function of the proportion of patients accurately staged and the risks, benefits, and costs of the diagnostic tests and treatments used. Probability estimates and costs were derived from primary data and the literature. We adopted a societal perspective and calculated incremental cost-effectiveness ratios (ICERs) as cost per quality-adjusted life year (QALY) gained. Both mediastinoscopy strategies correctly identified more patients with mediastinal involvement (N2/N3 disease) and assigned them to multimodal regimens. Routine mediastinoscopy maximized quality-adjusted life expectancy in all patients, irrespective of T classification, and this result was robust to varying the model estimates over their reported ranges. In T1 patients, selective mediastinoscopy cost $24,500 per QALY gained, compared with $78,800 per QALY gained for routine mediastinoscopy. In T2 and T3 patients, the ICER of routine mediastinoscopy was more favorable ($42,800 and $53,400 per QALY gained, respectively). Routine mediastinoscopy maximizes quality-adjusted life expectancy in patients with known NSCLC, and its ICER compares favorably with other currently accepted medical technologies. The survival benefit and cost-effectiveness of this strategy are greater in patients with T2 and T3 tumors and are likely to improve with advances in multimodal therapy.

Frequency of mediastinal lymph node metastases in patients undergoing EUS evaluation of pancreaticobiliary masses

Background: Mediastinal lymph node metastases have rarely been reported in patients with pancreatic cancer. Our aim was to determine the frequency of mediastinal lymph node metastases in patients with pancreaticobiliary masses by using EUS-guided fine needle aspiration. Methods: Sixty-six consecutive patients with pancreatobiliary masses were evaluated on EUS for the presence of mediastinal lymph node metastases. All masses were staged by commonly used EUS criteria by using sector scanning echoendoscopes. Mediastinal lymph nodes with EUS features that suggested malignancy were aspirated. Results: Of the 66 patients (mean age 65.6 years; 38 men), 4 had biliary masses, 5 had lesions of the major duodenal papilla, and 57 had pancreatic masses. Eleven patients (10 pancreatic masses, 1 biliary mass) had enlarged mediastinal lymph node (12-30 mm) on EUS; in 2 patients these had a benign appearance and were not aspirated. Nine patients underwent EUS-guided fine needle aspiration: in 1 the cytology was inconclusive (patient subsequently had a negative Whipple resection); in 4 the mediastinal lymph node cytology was benign; the remaining 4 patients had adenocarcinoma cells in the aspirate from mediastinal lymph node. These 4 pancreatic tumors were staged by EUS as T2N1M1 (1), as T4N0M1 (2, one later found to also have a lung mass), and T4N1M1 (1). Conclusion: Enlarged mediastinal lymph nodes were found on EUS in 16.6% (95% CI [7.7%, 25.6%]) of patients with pancreatobiliary masses and in 17.5% (95% CI [7.6%, 27.4%]) of patients with pancreatic masses. The frequency of mediastinal lymph node metastases in pancreatobiliary masses was 6.1% (95% CI [0.34%, 11.9%]) and in pancreatic masses 7.0% (95% CI [0.4%, 13.6%]). Routine EUS evaluation of the mediastinum in patients with pancreatic masses is warranted. (Gastrointest Endosc 2001;54:331-5.)

Malignant Peripheral Nerve Sheath Tumors of Intrathoracic Vagus Nerve

The authors report two cases of malignant peripheral nerve sheath tumors arising from the vagus nerve in the mediastinum in patients who had no stigmata of neurofibromatosis (von Recklinghausen's disease). Computed tomography showed homogeneous soft tissue masses, with minimal calcification seen in one patient. T2-weighted magnetic resonance images showed regions of low signal intensity caused by a dense cellular population.

The Role of Positron Emission Tomography in Evaluating Mediastinal Lymph Node Metastases in Non–Small-Cell Lung Cancer

Positron emission tomography (PET) is a modality that differentiates malignant from benign processes based upon metabolism rather than anatomy. A number of studies have confirmed improved accuracy of PET over computed tomography (CT), but until a few recent studies, most had failed to include satisfactory histologic confirmation. The objective of this study was to compare PET and CT to histologic staging of the mediastinum in patients with non–small-cell lung cancer (NSCLC). Histologic examination of mediastinal lymph nodes (MLNs) was performed on 40 patients with NSCLC at mediastinoscopy and/or at surgical resection. PET scans were interpreted by one of two nuclear medicine physicians, blinded to histology, using CT scans for anatomic localization. CT scans were independently evaluated for mediastinal lymphadenopathy. The overall accuracy, sensitivity, and specificity of PET were 78% (31 of 40), 67% (four of six), and 79% (27 of 34), respectively. The overall accuracy, sensitivity, and specificity of CT were 68% (27 of 40), 50% (three of six), and 71% (24 of 34), respectively. PET was superior to CT at correctly identifying mediastinal nodal metastases; however, both modalities were inferior to the gold standard of surgical staging. PET is more accurate than CT in staging the mediastinum of patients with NSCLC. PET failed to identify lymph node metastasis in 33% of patients with histologically proven MLN involvement, and false positives were present in 15%. At present, mediastinoscopy should remain the standard of care for preoperative mediastinal staging for NSCLC.

Mediastinal lymphadenopathy: an extrahepatic manifestation of chronic hepatitis C?

Normal and enlarged perihepatic and mediastinal lymph nodes are detectable by ultrasonography. Aim of the present study is to determine the detection rate, size, and correlation of mediastinal and perihepatic lymphadenopathy in patients with chronic hepatitis C, healthy controls, and patients with inflammatory or neoplastic mediastinal lymphadenopathy. The mediastinum and liver hilus of 89 patients with chronic hepatitis C as well as of 34 healthy volunteers and 20 patients with mediastinal lymphadenopathy of different origin with adequate sonographic visualization were screened for the number and size of lymph nodes by high resolution ultrasonography. Lymph nodes were detectable in the mediastinum of 75/89 (84%) patients with chronic hepatitis C and 22/34 (65%) healthy volunteers (total lymph node volume [LNV]: 1.0 +/- 0.8 mL versus 0.3 +/- 0.4 mL, p < 0.001). In all patients with mediastinal lymphadenopathy, the mediastinal lymph node volume was above 15 mL. In patients with chronic hepatitis C a trend could be observed, that patients with larger perihepatic lymph nodes reveal also larger mediastinal lymph nodes. High resolution ultrasonography is able to detect enlarged mediastinal lymph nodes in patients with chronic hepatitis C. Mediastinal lymphadenopathy is considered as an extrahepatic manifestation of chronic hepatitis C. In general, the mediastinal lymph node volume differs in size to patients with lymphadenopathy related to neoplasia or sarcoidosis. The mechanism of lymphadenopathy in the liver hilus and mediastinum in patients with chronic hepatitis C is yet unknown.

Use of fluorine-18 fluorodeoxyglucose positron emission tomography in the detection of thymoma: a preliminary report.

Thymomas are lacking in malignant cytological features. Their staging is defined by the invasiveness of the tumour. This study aimed to analyse the uptake patterns of fluorine-18 fluorodeoxyglucose (FDG) in thymomas of different stages. FDG positron emission tomography (PET) scan was performed in 12 patients suspected of having thymoma and in nine controls. Qualitative visual interpretation was used to detect the foci with FDG uptake higher than that of normal mediastinum. Tumour/lung ratio (TLR) was calculated from the counts of ROIs over the mass and over comparable normal lung tissue in thymoma patients. Mediastinum/lung ratio (MLR) was calculated from the counts of ROIs over the anterior mediastinum and lung in controls. The PET scan patterns of distribution of foci with FDG uptake and TLRs were correlated with the computed tomography (CT) or magnetic resonance imaging (MRI) findings, and staging of the thymomas. Thymectomy was performed in ten patients and thoracoscopy was done in two patients. The results revealed ten thymomas (two stage I tumours, two stage II, four stage III and two stage IV, according to the Masaoka classification), and two cases of thymic hyperplasia associated with myasthenia gravis. Myasthenia gravis was also noted in four thymoma patients. FDG studies showed (a) diffuse uptake in the widened anterior mediastinum in patients with thymic hyperplasia, (b) confined focal FDG uptake in the non-invasive or less invasive, stage I and II thymomas, and (c) multiple discrete foci of FDG uptake in the mediastinum and thoracic structures in stage III and IV advanced invasive thymomas. The thymomas had the highest TLRs, followed by the TLRs of thymic hyperplasia and the MLRs of control subjects (P <0.005). No significant difference was found between thymomas in different stages or between thymomas with and thymomas without myasthenia gravis. In comparison with CT and/or MRI, FDG-PET detected more lesions in patients with invasive thymomas and downgraded the staging of thymoma in four patients. Our preliminary results suggest that FDG-PET is useful in the assessment of the invasiveness of thymomas, and may have the potential to differentiate thymomas from thymic hyperplasia.

Radiologic Evaluation in Chest Malignancies: A Review of Imaging Modalities

Radiologic evaluation of the patient with non-small cell lung cancer (NSCLC) includes chest radiographs for detecting nodules, computed tomography (CT) for further characterizing them, CT and magnetic resonance imaging (MRI) to evaluate the mediastinum, and extrathoracic imaging of bones, the adrenal gland, the central nervous system, and liver. The current practice standards for each are reviewed. Asymptomatic solitary pulmonary nodules, which are usually detected on chest radiographs obtained for other indications, inevitably require a precise diagnosis. The radiologic characteristics that differentiate benign from malignant pulmonary lesions are given. Mediastinal CT is the preferred modality for examining the mediastinum in patients with NSCLC. Magnetic resonance imaging is used selectively, eg, in patients with superior sulcus tumors who are candidates for surgery. When evaluation for N2/N3 disease is requested, mediastinoscopy should replace CT using the latter as a "roadmap." The role of extrathoracic imaging in evaluating asymptomatic patients with NSCLC at initial presentation is equivocal. Computed tomographic scanning of the head is reasonable in most patients with lung cancer, given the significant incidence of occult brain metastases in this population and that solitary brain lesions may be resected in some protocol settings. Routine liver and adrenal gland scanning is similarly controversial. Bone scans do not appear to be useful in patients with NSCLC unless they have clinical signs, symptoms, or laboratory findings to indicate possible metastases. Although heavily affected by local practice, radiologic evaluation of the patient with NSCLC should attempt to provide accurate determination of local disease and a search for distant metastases.

Endoscopic Ultrasound Versus Computed Tomography in the Evaluation of the Mediastinum in Patients with Non-Small-Cell Lung Cancer

Endoscopic Ultrasound Versus Computed Tomography in the Evaluation of the Mediastinum in Patients with Non-Small-Cell Lung Cancer

Staging of the Mediastinum: Role of Mediastinoscopy and Computed Tomography

During the 1940s and 1950s, as many as 50% of thoracotomies identified nonresectable tumors. At present, better than 90% of patients undergoing thoracotomy for presumably resectable lung cancer are found to have operable tumors. This improvement is the result of major advances in the preoperative staging of this disease. Mediastinoscopy and computed tomography (CT) are the most valuable techniques for evaluating the mediastinum in patients with primary cancer of the lung. For each modality, the primary objective is to define the presence or absence of spread to mediastinal lymph nodes. In patients with non-small-cell lung cancer, surgical resection remains the treatment of choice so long as all recognizable tumor can be removed at operation. Both mediastinoscopy and CT provide critical information concerning the potential for a complete resection. Computed tomography remains the most effective noninvasive technique for the evaluation of mediastinal nodes.

Bronchoscopic and Roentgenographic Correlates of a Positive Transbronchial Needle Aspiration in the Staging of Lung Cancer

A study was conducted to determine the bronchoscopic and chest roentgenographic findings associated with a positive TBNA. One hundred fifty-seven of 465 patients who were diagnosed for the first time as having carcinoma of the lung had a positive aspirate. Bronchoscopic findings associated with a positive TBNA of N2 nodes were carinal widening and endobronchial disease, especially of the right upper lobe. Mediastinal adenopathy noted on chest roentgenograms and subcarinal nodes on CAT scans were associated with a positive aspirate as well. In 34 of 465 patients, TBNA was the only means of establishing the diagnosis of pulmonary malignancy. A useful, simple and safe procedure, TBNA can be used to stage the mediastinum in patients with lung cancer and is most likely to be positive with endobronchial and nodal disease. It can also facilitate therapeutic decision-making in patients whose surgical candidacy is marginal.

Does the mediastinum of patients with non-small cell lung cancer require histologic staging? Future standards for computed tomography.

We asked whether noninvasive staging of the mediastinum is a reasonable alternative to invasive staging in patients with non-small cell lung cancer. Decision analysis was used to compare strategies relying upon mediastinoscopy, bronchoscopy with transbronchial needle aspiration, and/or thoracotomy for histologic or cytologic confirmation of mediastinal stage to two strategies primarily relying upon computed tomography for assessing the mediastinum. Life expectancy was the outcome of interest. Extensive sensitivity analysis showed that, if the specificity of computed tomography for mediastinal disease was above 0.90, a strategy primarily relying upon computed tomography to stage the mediastinum would provide a life expectancy within 1 month of that provided by invasive testing. The difference in life expectancy between the invasive and noninvasive staging strategies decreased further as the prior probability of unresectable disease increased. Surprisingly, the sensitivity of computed tomography for mediastinal disease was of little importance in determining overall life expectancy. These results suggest that noninvasive imaging techniques might reliably replace invasive mediastinal staging if their specificity exceeds 0.90.

Current Use of Imaging in the Evaluation of Primary Mediastinal Masses

A wide variety of lesions occur in the mediastinum in patients of every age. Twenty five to 50 percent of these primary mediastinal masses may be malignant, making early diagnosis and therapy crucial. Since most arise from normal structures in the region, localization of lesions to compartments of the mediastinum may assist in diagnosis. This article reviews imaging techniques for lesions originating in the mediastinum.

Current Uses of CT and MR Imaging in the Staging of Lung Cancer

In 1986, Pearson reported on the lung cancer experience in Toronto over the past 25 years. The number of unresectable operations had decreased from 25 to 5%. Operative mortality was down from 10 to 3% and 5-year survival increased from 23 to 40%. The reason for these statistics, he stated, was not better surgery but better selection of surgical candidates, due to invasive and noninvasive techniques. CT and MR imaging are part of those noninvasive techniques and also play an important role in guiding the invasive techniques. Although controversy exists regarding the proper size criteria and axis length in nodal assessment, and the use of imaging in staging T1N0M0 lung cancer, most clinicians rely on CT scans to evaluate the patient with lung cancer. No other imaging test is as comprehensive in evaluating the patient with lung cancer. The main role of MR imaging at this time is as a problem-solving tool. Focused MR imaging examinations should be used to evaluate or to resolve specific questions related to invasion of the chest wall, vascular structures, or brachial plexus, and adrenal mass characterization. MR imaging is also useful in evaluating the hilum and mediastinum in patients who cannot receive intravenous contrast for CT evaluation. The overall accuracy of CT and MR imaging is disappointing, particularly in crucial areas of determining operability such as distinguishing between patients with Stage IIIA or IIIB disease. It is unlikely that CT diagnosis can significantly improve; however, there is substantial potential for improved diagnostic accuracy with MR imaging as continued research moves this technology forward. The future may bring improved tissue characterization and vascular evaluation. At present, CT remains the procedure of choice in the initial assessment of the patient with lung cancer. The radiologist must be prepared to interpret these imaging studies in light of the specific findings that determine the stage and thus potential resectability of lung cancer.

Mediastinoscopy in the investigation of primary mediastinal lymphadenopathy.

Mediastinoscopy was introduced by Carlens (1) in 1959 to obtain lymph node biopsies from the superior mediastinum in patients with bronchogenic carcinoma. The technique has been widely accepted for clinical staging as a guide to operability and prognosis. We report on a consecutive retrospective series of 110 patients undergoing mediastinoscopy between 1982-1986 for primary mediastinal lymphadenopathy in order to assess the diagnostic value and safety of the procedure. Mediastinoscopy gave a positive histological diagnosis in 74.5% of cases with no false negative results. There were no deaths and one complication only (pneumothorax). This study shows mediastinoscopy to be a safe, accurate and cost effective procedure minimising hospital stay and allowing appropriate treatment to be immediately commenced upon diagnosis. Mediastinoscopy obviates the need for expensive computed tomography or nuclear magnetic resonance scans and we conclude that it is the investigation of choice for primary mediastinal lymphadenopathy after confirmation by plain chest radiography.

Role of computerized tomography in assessment of the mediastinum in patients with lung carcinoma

Role of computerized tomography in assessment of the mediastinum in patients with lung carcinoma