Evaluation of different classification methods using electronic nose data to diagnose sarcoidosis.

Electronic nose (eNose) technology is an emerging diagnostic application, using artificial intelligence to classify human breath patterns. These patterns can be used to diagnose medical conditions. Sarcoidosis is an often difficult to diagnose disease, as no standard procedure or conclusive test exists. An accurate diagnostic model based on eNose data could therefore be helpful in clinical decision-making. The aim of this paper is to evaluate the performance of various dimensionality reduction methods and classifiers in order to design an accurate diagnostic model for sarcoidosis. Various methods of dimensionality reduction and multiple hyperparameter optimised classifiers were tested and cross-validated on a dataset of patients with pulmonary sarcoidosis (n= 224) and other interstitial lung disease (n= 317). Best performing methods were selected to create a model to diagnose patients with sarcoidosis. Nested cross-validation was applied to calculate the overall diagnostic performance. A classification model with feature selection and random forest (RF) classifier showed the highest accuracy. The overall diagnostic performance resulted in an accuracy of 87.1% and area-under-the-curve of 91.2%. After comparing different dimensionality reduction methods and classifiers, a highly accurate model to diagnose a patient with sarcoidosis using eNose data was created. The RF classifier and feature selection showed the best performance. The presented systematic approach could also be applied to other eNose datasets to compare methods and select the optimal diagnostic model.

Multidisciplinary approach to thoracic tissue sampling.

When choosing the best method to undertake a biopsy of a lesion in the lung or mediastinum, it is important to consider the entire range of possible options, such as surgical, bronchoscopic/endoscopic, and radiologic techniques. Features to be considered include the anatomic location of the lesion, the amount of tissue needed, cost, availability of specific techniques, safety and risks, and expected diagnostic yield/accuracy.

Aortic growth rates in chronic aortic dissection.

AIM: To determine and compare rates of descending aortic enlargement and complications in chronic aortic dissection with and without a proximal aortic graft. METHODS AND MATERIALS: Fifty-two patients with dissection involving the descending aorta and who had undergone at least two computed tomography (CT) examinations at our institution between November, 1993 and February, 2004 were identified, including 24 non-operated patients (four type A, 20 type B) and 28 operated patients (type A). CT examinations per patient ranged from two to 10, and follow-up ranged from 1-123 months (mean 49 months, median 38.5 months). On each CT image, the aortic short axis (SA), false lumen (FL), and true lumen (TL) diameters were measured at the longitudinal midpoint of the dissection and at the point of maximum aortic diameter. Complications were tabulated, including aortic rupture and aortic enlargement requiring surgery. RESULTS: For non-operated patients, the midpoint and maximum point SA, TL, and FL diameters increased significantly over time. For operated patients, the midpoint and maximum point SA and FL diameters increased significantly over time. In both groups, aortic enlargement was predominantly due to FL expansion. Diameter increases in non-operated patients were significantly larger than those in operated patients. The rate of change in aortic diameter was constant, regardless of aortic size. Four non-operated and six operated patients developed aortic complications. CONCLUSIONS: In patients with a dissection involving the descending thoracic aorta, the FL increased in diameter over time, at a constant rate, and to a greater degree in non-operated patients (mostly type B) compared with operated patients (all type A).

[Rituximab and autoimmune disorders therapy]. / Anticorps monoclonal anti-CD20 et traitement des maladies auto-immunes.

INTRODUCTION: B lymphocytes play a central role in pathogenesis of autoimmune disease. This suggests that therapies directed against B lymphocytes may be effective for the treatment of human autoimmune mediated disease. EXEGESIS: Rituximab is a chimeric monoclonal antibody directed against the CD20 antigen expressed on most B cells and is used to treat B cell non Hodgkin lymphoma. Rituximab is highly effective in depleting B lymphocytes in vivo. Such treatment could presumably eliminate B cells producing autoantibodies. Main mechanisms of action of Rituximab are discussed with implication in the management of autoimmune diseases. CONCLUSION: Use of Rituximab for autoimmune disorders therapy is attractive because of its effect on B lymphocytes. However, therapeutics indications have to be adapted to the inherent differences in the pathogenesis of autoimmune diseases to assess efficiency.

Aortic dissection: CT features that distinguish true lumen from false lumen.

OBJECTIVE: The purpose of this study was to determine which CT findings are reliable indicators of the true or false lumen in an aortic dissection. CONCLUSION: The beak sign and a larger cross-sectional area were the most useful indicators of the false lumen for both acute and chronic dissections. Features generally indicative of the true lumen included outer wall calcification and eccentric flap calcification. In cases showing one lumen wrapping around the other lumen in the aortic arch, the inner lumen was invariably the true lumen.

Diaphragmatic shape change after lung volume reduction surgery.

Diaphragmatic shape in normal patients was significantly different from shape in emphysema patients. Postoperative diaphragmatic shape in patients with good clinical outcome differed from preoperative shape and was similar to shape in normal patients. In patients with poor clinical outcome, surgery appeared to have little effect on diaphragm shape.

Evaluation of competence in the interpretation of chest radiographs.

RATIONALE AND OBJECTIVES: The purpose of this study was to determine relative rates of missed diagnoses for radiologists as a measure of competence in interpreting chest radiographs. MATERIALS AND METHODS: Cases involving differing interpretations of chest radiographs were collected from January 1994 through December 1999 by faculty (chest and nonchest radiology specialists) in an academic radiology department. A quarterly peer-review process designated cases months after the fact, and anonymously, as no miss or as class I (nondiagnosable), class II (very difficult diagnosis), class III (should be diagnosed most of time), or class IV (should almost always be diagnosed) missed diagnoses. The rates and classes of missed diagnoses were compared among chest faculty and for the nonchest radiology specialists as a group. RESULTS: Chest radiologists read 184,977 studies, and nonchest radiologists read 300,684 studies. Of these, 243 missed diagnoses were classified (classes I and II, 184 cases; class III, 50; and class IV, nine). No difference was detected in the rate of class III and IV misses among chest faculty, but nonchest faculty had significantly more class III (P = .022) and class IV misses (P = .016). CONCLUSION: Random sampling of differing interpretations can yield a relative rate of missed diagnoses for radiologists. No difference was detected in clinically important misses (ie, classes III and IV) among chest radiologists, but a statistically significantly higher rate of seemingly obvious misdiagnoses was found for nonchest specialty radiologists. Potential biases may have influenced this analysis, including disease prevalence, sampling, clinical factors, observer variability, and truth-in-diagnosis.

Ulcerlike lesions of the aorta: imaging features and natural history.

PURPOSE: To document the natural history of ulcerlike aortic lesions and determine whether any computed tomographic (CT) features predict outcome. MATERIALS AND METHODS: CT scans from 1994 to 1998 that depicted an ulcerlike aortic lesion were retrospectively evaluated. Features evaluated included lesion and aortic size and intramural hematoma. Initial CT findings were correlated with clinical data and subsequent CT findings. RESULTS: There were 56 lesions in 38 patients. Follow-up (mean, 18.4 months) CT scans were available for 33 lesions. Stability of the lesion and adjacent aorta was noted in 21 lesions. Two lesions were unchanged, although associated intramural hematoma regressed over 1-2 months. Ten lesions showed mild to moderate increase in aortic diameter (mean follow-up, 19.8 months) either with (seven lesions) or without (one lesion) increase in size of the lesion or with incorporation of the lesion into the aortic wall contour (two lesions). Of all 56 lesions, 37 were clinically stable, two were associated with recurrent chest and/or back pain, eight underwent surgical resection or stent placement, and two were in patients who died. Seven lesions were in patients lost to follow-up. No initial CT feature was predictive of CT outcome, although lack of pleural effusion correlated with clinical stability. CONCLUSION: Most ulcerlike aortic lesions are asymptomatic and do not enlarge. About one-third of lesions progress, generally resulting in mild interval aortic enlargement.

Solitary pulmonary nodules in patients with extrapulmonary neoplasms.

PURPOSE: To determine the frequency of single lung metastasis, primary lung cancer, and benign lesions in patients with a solitary lung nodule and a primary extrapulmonary neoplasm. MATERIALS AND METHODS: The authors evaluated the electronic charts of 149 patients with an extrapulmonary malignant neoplasm and a solitary pulmonary nodule. The histologic characteristics of the nodule were correlated with those of the extrapulmonary neoplasm and with patient age and smoking history. RESULTS: Patients with carcinomas of the head and neck, bladder, breast, cervix, bile ducts, esophagus, ovary, prostate, or stomach were more likely to have primary bronchogenic carcinoma than lung metastasis (ratio, 25:3 for patients with head and neck cancers; 26:8 for patients with other types of cancer combined). Patients with carcinomas of the salivary glands, adrenal gland, colon, parotid gland, kidney, thyroid gland, thymus, or uterus had fairly even odds (ratio, 13:16). Patients with melanoma, sarcoma, or testicular carcinoma were more likely to have a solitary metastasis than a bronchogenic carcinoma (ratio, 23:9). Thirty patients had a benign nodule. There was substantial overlap in age distribution among the patients with benign disease, lung cancer, and metastasis, although no patient younger than 44 years had a lung cancer. Smokers had a 3.5-fold higher chance of developing lung cancer compared with nonsmokers. CONCLUSION: The likelihood of a primary lung cancer versus a metastasis depends on the histologic characteristics of the extrapulmonary neoplasm and the patient's smoking history.

Haemophagocytic syndrome associated with plasmodium vivax infection.

A 41-year-old woman was admitted with fever, splenomegaly and pancytopenia. High serum ferritin, hypertriglyceridaemia and bone marrow haemophagocytosis were consistent with a haemophagocytic syndrome. Trophozoites and gametocytes of Plasmodium vivax were identified on blood smear. Rapid recovery was observed after treatment with oral chloroquine.

[Polyclonal B lymphocytosis and hyper-IgM: immunodeficiency and/or benign lymphoid proliferation associated with tobacco?]. / Hyperlymphocytose B polyclonale et hyper-IgM: déficit immunitaire et/ou prolifération lymphoïde bénigne associé(s) au tabac?

PURPOSE: To study the association of polyclonal B-cell lymphocytosis with binucleated lymphocytes with clinical manifestations suggesting the existence of an immunodeficiency, to evaluate the effect of cigarette smoking on this 'benign lymphoid proliferation', to analyze the clonality of lymphocytes, to determine the levels of immunoglobulins (Ig) G, A, M. METHODS: Description and analysis of the results obtained in four patients and literature review. RESULTS: Polyclonal B-cell lymphocytosis is associated with both a decrease in IgA and IgG and an increase in IgM. Recurrent infectious episodes (bronchitis) were observed in two patients. Transient smoking cessation allowed a decrease in lymphocytosis and IgM levels in two patients. No hematological malignancy occurred during the follow-up, while biological abnormalities persisted. CONCLUSION: Persistent polyclonal B-cell lymphocytosis may be associated with minor clinical features of immunodeficiency. Smoking cessation may sometimes lead to a decrease in lymphocytosis and IgM.

MR imaging of levator ani muscle recovery following vaginal delivery.

Our aim was to quantify the changes that occur in the levator ani muscles (LA) after vaginal delivery using magnetic resonance imaging. Fourteen women underwent MRI 1 day postpartum. Six of them were also scanned 1, 2, 6 weeks and 6 months after delivery. LA signal intensities and thickness, in areas of the urogenital and the levator hiatus were assessed in the transverse plane. Perineal body position was measured in the sagittal plane. One day postpartum a higher T2-signal intensity of the LA compared to the obturator internus muscle was found in all women and a lower T1-signal intensity in 8 of 12 women. By 6 months these differences were present in only 1 woman in the left LA. An elevation in perineal body position of 13.4 +/- 7.3 mm (P < 0.05), as well as a decrease in the area of the urogenital hiatus by 27% (P<0.05) and of the levator hiatus by 22% (P < 0.05) by 2 weeks postpartum suggest a return of normal LA geometry. LA thickness showed interindividual variations, and a complete loss of LA tissue was found in 1 woman. Changes in LA signal intensity, topography and thickness during the puerperium can be documented using MR imaging.

Radiologic staging of lung cancer.

Preoperative tumor staging in patients with known or suspected non-small cell lung cancer is generally performed using contrast enhanced chest computed tomography (CT) (including the adrenal glands). Abdominal CT is generally unnecessary, given the low frequency of isolated liver metastases. The role of MRI is limited, and it is used mainly as a problem solving tool in certain specific situations. A CT showing no mediastinal lymph node enlargement usually oviates preoperative mediastinal lymph node sampling, with certain exceptions. If enlarged mediastinal lymph nodes are demonstrated at CT, then CT may be used to direct preoperative lymph node sampling via transbronchoscopic Wang needle biopsy, mediastinoscopy, mediastinotomy, or video assisted thoracoscopy.

Risk analysis for aortic surgery using hypothermic circulatory arrest with retrograde cerebral perfusion.

BACKGROUND: Retrospective analysis of 144 patients undergoing aortic arch reconstruction using hypothermic circulatory arrest (HCA) with retrograde cerebral perfusion (RCP) for cerebral protection was performed. METHODS: The diagnosis, procedure, and anatomic site of the arch anastomosis were analyzed to see if they were independent predictors of mortality or morbidity. In addition age, gender, HCA-RCP times, preoperative malperfusion (both treated and untreated), surgical status, and redo surgery status were also examined to determine their influence on the incidence of death and complications. Both multivariate and univariate analysis were performed using linear regression and cross-tabulation with either chi2 or Fisher's exact test where appropriate. RESULTS: Preoperative surgical status (emergent) and the presence of untreated preoperative malperfusion were the only variables that were significant independent predictors for mortality (p <0.05). No variable was significant for the prediction of stroke or other complications. The severity of surgery had no bearing on the patient outcome. CONCLUSIONS: Complex aortic surgery using HCA-RCP can be performed with acceptable risk to the patients.

Synthetic interposition grafts of the thoracic aorta: postoperative appearance on serial CT studies.

PURPOSE: To determine the normal postoperative appearance of thoracic aortic interposition grafts on serial CT studies and to document CT detectable complications. MATERIALS AND METHODS: The 235 CT studies in 114 patients with one or more thoracic aortic interposition grafts were analyzed for the presence or absence of felt rings, felt pledgets, low-attenuation material surrounding the graft, pseudoaneurysm, and dissection flap. A graft was present in the ascending aorta in 93 patients, in the descending aorta in 25, and in the arch in 11. RESULTS: Low-attenuation material was seen adjacent to the ascending graft in 55%-82% of patients and adjacent to the descending graft in 60%-79% of patients, showing diminishing frequency and thickness over time. CT scans in 30 of 53 patients showed residual low-attenuation material adjacent to the graft more than 1 year after surgery. CT scans in four of 93 patients with ascending grafts and one of 25 patients with descending grafts showed a pseudoaneurysm. CONCLUSION: CT studies obtained after aortic interposition grafting show characteristic findings. Knowledge of the type of operative procedure and typical location and CT appearance of surgical materials used is important to correctly diagnose or exclude postoperative complications following thoracic aortic interposition grafting.

Probing immunoglobulin gene hypermutation with microsatellites suggests a nonreplicative short patch DNA synthesis process.

As the rate of Ig gene hypermutation approximates the level of nucleotide discrimination of DNA polymerases (10(-3) to 10(-4)), a local inhibition of proofreading and mismatch repair during semiconservative replication could generate the mutations introduced by the process. To address this question, we have constructed transgenic mice that carry a hypermutation substrate containing a "polymerase slippage trap": an Ig gene with a mono or dinucleotide tract inserted in its V region. The low amount of slippage events as compared to the number of mutations, the absence of transient misalignment mutations at the border of the repeats, and the dissociation between the amount of frameshifts and mutations when the transgene is put on mismatch repair-deficient genetic backgrounds, suggest that Ig gene hypermutation occurs by an error-prone short patch DNA synthesis taking place outside global DNA replication.

Mismatch repair deficiency interferes with the accumulation of mutations in chronically stimulated B cells and not with the hypermutation process.

Primary responses to the hapten phenyloxazolone and chronic responses to environmental antigens occurring in Peyer's patches were analyzed in two different mismatch repair-deficient backgrounds. Paradoxically, whereas primary responses were found normal in MSH2- and only slightly diminished in PMS2-deficient mice, mutations in Peyer's patch B cells from both k.o. animals were reduced three times, the subset of Peyer's patch B cells with highly mutated sequences being specifically missing in the mismatch repair-deficient context. Strikingly, germinal center B cells from Peyer's patches of k.o. animals showed microsatellite instability at an unprecedented level. We thus propose that the amount of DNA damages generated prevents these cells from recycling in germinal centers and that mismatch repair deficiency is only the indirect cause of the lower mutation incidence observed.