Clinical value of whole-blood interferon-gamma assay in patients with suspected pulmonary tuberculosis and AFB smear- and polymerase chain reaction-negative bronchial aspirates

Combining a polymerase chain reaction (PCR) test with bronchoscopy is frequently performed to allow a rapid diagnosis of smear-negative pulmonary tuberculosis (PTB). However, limited data are available concerning clinical judgment in patients with suspected PTB and AFB smear- and PCR-negative bronchial aspirates (BA). The present study evaluated the usefulness of whole-blood QuantiFERON-TB Gold In-Tube (QFT) testing in these patients. Of 166 patients with suspected PTB who had undergone bronchoscopy because of smear-negative sputum or inadequate sputum production, 93 (56%) were diagnosed with culture-positive PTB. Seventy-four patients were either AFB smear- or PCR-positive. In the 75 patients whose BA AFB smear and PCR results were both negative, 19 were finally diagnosed with PTB by culture. The QFT test had a negative predictive value of 91% for PTB. The QFT test may be useful for excluding PTB in patients with suspected PTB whose BA AFB smear and PCR results are both negative.     

Assessing the utility of the Xpert Mycobacterium tuberculosis/rifampin assay for analysis of bronchoalveolar lavage fluid in patients with suspected pulmonary tuberculosis

BackgroundThere is limited research assessing the utility of the Xpert Mycobacterium tuberculosis/rifampin (MTB/RIF) assay for the analysis of bronchoalveolar lavage fluid (BALF) in Chinese patients with suspected pulmonary tuberculosis (PTB). Thus, our objective was to determine the diagnostic accuracy of the Xpert MTB/RIF assay and evaluate its utility for the determination of rifampicin resistance.MethodsWe retrospectively analyzed BALF from 214 patients with suspected PTB between January 2018 and March 2019. Using mycobacterial culture or final clinical diagnosis as the reference standard, the diagnostic accuracy of the smear microscopy (SM), tuberculosis bacillus DNA (TB‐DNA), Xpert MTB/RIF assay, and the determination of rifampicin resistance based on the Xpert MTB/RIF assay were compared.ResultsAs compared to mycobacterial culture, the sensitivity of the Xpert MTB/RIF assay, SM, and TB‐DNA were 85.5% (74.2%–93.1%), 38.7% (26.6%–51.9%), and 67.7% (54.7%–79.1%), respectively. As compared to the final diagnosis, the specificity of the Xpert MTB/RIF assay, SM, and TB‐DNA were 100.0% (95.9%–100.0%), 94.3% (87.1%–98.1%), and 98.9% (93.8%–100.0%), respectively. The sensitivity and specificity of the rifampicin resistance detection using the Xpert MTB/RIF assay were 100% and 98.0%, respectively, with liquid culture as the reference.ConclusionsThis study demonstrates that the analysis of BALF with the Xpert MTB/RIF assay provides a rapid and accurate tool for the early diagnosis of PTB. The accuracy of diagnosis was superior compared with the SM and TB‐DNA. Moreover, Xpert is a quick and accurate method for the diagnosis of rifampicin‐resistant tuberculosis and can also provide more effective guidance for the treatment of PTB or multidrug‐resistant tuberculosis (MDR‐TB).     

Comparison of quantitative polymerase chain reaction,acid fast bacilli smear,and culture results in patients receiving therapy for pulmonary tuberculosis

Quantitative-competitive polymerase chain reaction (QPCR) was performed on serial sputum samples from 22 consecutive cases of acid fast bacilli (AFB) smear-positive pulmonary tuberculosis. Of 94 specimens, 55, 72, and 83% were positive by culture, AFB smear, and QPCR, respectively. Of 52 culture-positive specimens, 6% were negative by PCR, and 13% were negative by AFB smear. Of 42 culture-negative specimens, AFB smear and QPCR were positive in 55 and 61%, respectively. AFB smear and QPCR results were strongly correlated (r = 0.75, p < 0.001), but each correlated less strongly with culture (r = 0.54, p < 0.005 for smear and r = 0.52, p < 0.005 for QPCR). When patients were classified by microbiologic response, responders tended to have less DNA in their sputum and shorter time to a negative PCR result compared to nonresponders. These data do not suggest a great advantage of QPCR over AFB smear for predicting culture results in patients with pulmonary tuberculosis.     

Usefulness of induced sputum and fibreoptic bronchoscopy specimens in the diagnosis of pulmonary tuberculosis

We investigated the diagnostic value of induced sputum (IS) and bronchial lavage (BL) specimens in patients with suspected pulmonary tuberculosis who had negative spontaneous sputum specimens or who were unable to produce sputum spontaneously. IS specimens and BL specimens obtained using flexible fibreoptic bronchoscopy from 55 patients were evaluated for the presence of acid-fast bacilli (AFB) and cultured for Mycobacterium tuberculosis. Positive results were found with IS smear in 23 patients, BL smear in 26 patients, and IS or BL culture in 42 patients. Culture of BL specimens had a higher sensitivity than IS or BL smears or culture of IS specimens. The highest sensitivity rate was obtained with a positive BL or IS culture (86%). For early diagnosis (a positive IS or BL smear), the sensitivity was 57%. IS has a higher sensitivity rate than spontaneous sputum for the detection of tuberculosis, and fibreoptic bronchoscopy is useful for the early diagnosis of tuberculosis when AFB are not detected in spontaneous or induced sputum specimens.     

Utility of B-cell epitopes based peptides of RD1 and RD2 antigens for immunodiagnosis of pulmonary tuberculosis

Tuberculosis (TB) continues to be a major health problem due to lack of accurate, rapid, and cost-effective diagnostic tests. Serodiagnostic tests incorporating highly specific region of difference (RD) antigens (early secretory antigenic target 6 [ESAT-6], culture filtrate protein 10 [CFP-10], culture filtrate protein 21 [CFP-21], and mycobacterial protein from species tuberculosis 64 [MPT-64]) have recently been shown to be promising for specific diagnosis of TB in our lab. However, only few studies have reported the use of synthetic peptides of RD antigens, and none has used them to differentiate TB from sarcoidosis, a close mimic of smear-negative pulmonary TB (PTB) with entirely different management. The present study was conducted with an aim to study the utility of B-cell epitopes based peptides of RD1 (ESAT-6, CFP-10) and RD2 (CFP-21, MPT-64) antigens for immunodiagnosis of PTB for which sputum smear-positive PTB patients, sputum smear-negative PTB patients, sarcoidosis patients, and healthy controls (n = 24/group) were recruited. Bioinformatic software Bcepred was used to predict linear B-cell epitopes, using physico-chemical properties on a non-redundant dataset. Seven peptides as representative B-cell epitopes of ESAT-6, CFP-10, CFP-21, and MPT-64 were evaluated as targets of the antibody responses in TB patients and controls by enzyme-linked immunosorbent assay (ELISA). The current study showed sensitivity with individual peptides ranging from 37.5% to 83.3% for smear positive, 25% to 58.3% for smear negative as compared to 4.16% to 20.8% for sarcoidosis. Four out of 7 peptides that showed higher reactivity with TB patients and better discrimination from sarcoidosis patients representing ESAT-6, CFP-10, CFP-21, and MPT-64 were selected for multiepitope ELISA. The combination of peptides yielded 83.3% sensitivity for smear positive, 62.5% for smear negative, and only 4.16% for sarcoidosis. The specificity, however, for all the peptides/combination was 100%. Combination of peptides has proven to be better than individual peptides as per the latest criteria of the World Health Organization according to which a test that can replace smear microscopy with sensitivity of >90% for smear-positive patients and >65% for smear-negative TB patients with a specificity >95%, and thus, the present study suggests that a test based on combination of peptides selected from mycobacterial RD1 and RD2 antigens could be important for promoting an early diagnosis and management of otherwise difficult to diagnose smear-negative PTB patients. Moreover, it can also be used to discriminate sarcoidosis from PTB, thus preventing the misdiagnosis and mismanagement.     

Usefulness of gastric aspirate for the diagnosis of smear-negative pulmonary tuberculosis

IntroductionGastric aspirate can be useful for the diagnosis of pulmonary tuberculosis (TB) in patients with smear-negative pulmonary TB or without sputum production. The gastric aspirate smear technique has low sensitivity, and a previous report demonstrated that no patient was diagnosed by only gastric aspirate analysis. However, some patients with TB have been negative on sputum examination but positive on gastric aspirate examination, and the incidence of such cases is uncertain. Therefore, this study investigated the usefulness of gastric aspirate in the diagnosis of pulmonary TB.MethodsTo analyze the diagnostic accuracy of gastric aspirate examination, the data of 513 patients with negative sputum smears or a lack of sputum production, including 203 patients with pulmonary TB (39.6%) and 93 patients with nontuberculous mycobacteriosis who underwent gastric aspiration at Fukujuji Hospital from January 2016 to March 2021, were collected retrospectively.ResultsThe accuracy rates of gastric aspirate examination for the diagnosis of pulmonary TB were as follows: 21.2% sensitivity and 91.9% specificity for smear positivity, 55.8% sensitivity and 99.6% specificity for nucleic acid amplification test positivity, and 71.4% sensitivity and 100% specificity for culture positivity. Twenty-three patients (11.2%) were diagnosed by gastric aspirate examination alone. Among the 356 patients who underwent three repeated sputum examinations in addition to gastric aspirate examination, the cumulative diagnostic rate for the 3 mycobacterial examinations plus gastric aspirate examination was higher than that for only three sputum examinations.ConclusionsGastric aspirate is useful for the diagnosis of TB in patients with smear-negative pulmonary TB or without sputum production.     

Magnetic bead flocculation test: Improving the diagnosis of tuberculous meningitis (TBM) in low-resource settings

BackgroundDespite several recent advances in detection techniques, there is still an unmet need for simple tests for the diagnosis of tuberculous meningitis (TBM). Therefore, in an effort towards developing a simple and rapid diagnostic test for resource-poor settings, we designed an assay in which magnetic bead flocculation test (MBF) was used to detect the amplified DNA. Multi-targeted (using two multicopy gene targets IS6110 and IS1081) loop-mediated isothermal amplification (MLAMP) was used for amplification.MethodsMLAMP-MBF assay was performed on CSF samples of 600 patients, out of which 120 were definite TBM (culture confirmed), 280 were probable TBM and 200 were non-TB controls, based on Marais's criteria. The performance of assay was evaluated by comparing the result of definite TBM with culture and that of probable TBM with composite reference standard consisting of clinical, microbiological(smear/culture) and radiological parameters.ResultsThe overall sensitivity of MLAMP-MBF (using any of the two gene targets) was 89.5% and specificity was 100%. The sensitivity was 96.6% (116/120) in diagnosing definite TBM and 86.4% (242/280) in diagnosing probable TBM. The sensitivity of IS1081 was 88% and that of IS6110 was 83% in diagnosing TBM. Specificity of both the gene targets was 100%. There were 20 cases positive only by IS1081 LAMP and 6 cases positive only by IS6110; thus 26 of 400 (6.5%) TBM cases could be additionally detected following multi-targeted approach.ConclusionMLAMP-MBF is a sensitive, robust, cost-effective and promising technique for diagnosis of TBM in low-resource high-endemic settings.     

Factors associated with acid-fast bacillus isolation in patients with noncystic fibrosis bronchiectasis: A cross-sectional study

IntroductionAcid-fast bacillus (AFB) is a major pathogen that causes noncystic fibrosis bronchiectasis requiring multidrug chemotherapy. Bronchoscopic bronchial wash is performed to determine the causative pathogens of bronchiectasis; but, predictive factors for AFB isolation have not been fully elucidated. This study aimed to determine the factors associated with AFB isolation from bronchial wash samples.MethodsThis was a single-center, cross-sectional study. Patients undergoing bronchoscopic bronchial wash for bronchiectasis were included, whereas those who did not undergo high-resolution computed tomography (HRCT); had acute pneumonia, interstitial lung disease, and a positive polymerase chain reaction result but a negative culture result for AFB; or in whom a guide sheath was used for suspected lung cancer were excluded. Binomial logistic regression was used to analyze the factors associated with a positive culture for AFB.ResultsOf the 96 included cases, AFB isolation was observed in the bronchial wash fluid of 26 patients (27%). No smoking history, a positive result for antiglycopeptidolipid (GPL)-core IgA antibody, and the presence of tree-in-bud appearance, multiple granular and nodular images on HRCT were more commonly observed in patients with AFB isolation than in those without. In the multivariate analysis, the tree-in-bud appearance (odds ratio, 4.223; 95% CI, 1.046–17.052) and anti-GPL core IgA antibody (odds ratio, 9.443; 95% CI, 2.206–40.421) were significantly associated with AFB isolation.ConclusionsThe tree-in-bud appearance on HRCT is likely to predict AFB isolation independent of anti-GPL core IgA antibody results. Bronchoscopic bronchial wash should be recommended for bronchiectasis with multiple granulomas on HRCT.     

Differentiation of mycobacteria in sputa by duplex polymerase chain reaction for mycobacterial hsp65 gene

Early differentiation of mycobacteria in sputa is crucial. This study was set to evaluate the usefulness of a newly developed duplex polymerase chain reaction (PCR) for hsp65 gene-based method in differentiating mycobacteria in sputum with a positive acid-fast bacilli (AFB) smear before culturing. One hundred forty-seven sputa with positive AFB smear were included for the analysis. Mycobacterial species were identified using a newly developed duplex PCR for hsp65 gene followed by a nested PCR-direct sequencing and the conventional colony-based method. Final decision of mycobacterial species were made based on 1) results of species identification based on mycobacterial colonies or 2) results of species identification of other sputa from the same patients and clinical findings. The duplex PCR-based method correctly identified 83.2% sputa from tuberculosis patients and 82.2% sputa from nontuberculous mycobacteria patients, whereas the colony-based method correctly identified 86.1% and 77.8%, respectively. Sensitivity and specificity of the colony-based method for Mycobacterium tuberculosis were 86.1% and 100%, respectively, whereas those of the duplex PCR-based method were 83.2% and 95.6%, respectively. The duplex PCR-based method, to differentiate mycobacterial species in sputa, produced comparable results as those of the colony-based identification method.     

Rapid detection of Mycobacterium tuberculosis in sputum by Patho-TB kit in comparison with direct microscopy and culture

The usefulness of a new rapid diagnostic test (Patho-TB) using antibodies specific to mycobacterial antigens was evaluated for the rapid discrimination between pulmonary tuberculosis (TB) and non-TB pulmonary diseases on sputa. One hundred sputa collected from 79 active TB patients and from 21 patients with non-TB pulmonary diseases (asthma and chronic obstructive pulmonary disease) were enrolled into the study and tested for the presence of Mycobacterium tuberculosis by Ziehl–Neelsen smear, Patho-TB kit, and Löwenstein–Jensen culture. The sensitivity, specificity, positive predictive value, and negative predictive value of the Patho-TB test were 95%, 100%, 100%, and 84%, respectively. Patho-TB test is simple, quick, and easy to perform. Its sensitivity, specificity, and positive predictive value are satisfactory. Therefore, it could be used as a screening test in poorly equipped laboratories of TB endemic areas.     

Bronchoalveolar lavage in pulmonary tuberculosis: a decision analysis approach

We assessed the utility of bronchoalveolar lavage (BAL) in thediagnosis of pulmonary tuberculosis (PTB) in 50 consecutiveHIV-negative patients with clinical and radiographic findingssuggestive of PTB, but with negative microscopy for acid-fastbacilli (AFB) on sputum smear. Patients were grouped, usinga scoring system, into relative likelihoods of having PTB (I—IV,in descending probability). Patients were started on anti-tuberculosistreatment according to the BAL results. Bacteriological diagnosisof PTB was confirmed in 22/50 BAL; 11 (91.6%), seven (37%) andfour (40%) of groups I–III, respectively. In 13 cases,an early diagnosis of PTB was made by positive microscopy forAFB on BAL; an alternative diagnosis was made in six cases (bacterialpneumonia 4, carcinoma 2). A decision analysis model was createdto assess the overall utility of BAL. This suggested that ina region of high PTB prevalence, and when the clinical diagnosisof PTB is likely, empirical treatment is the best course ofaction, with BAL being reserved for further investigation ofnon-responders. Early BAL should be considered when the diagnosisof PTB is uncertain.     

Rapid, sensitive, and specific detection of Mycobacterium tuberculosis complex by real-time PCR on paraffin-embedded human tissues

The detection of Mycobacterium tuberculosis complex (MTB) in clinical specimens is important for diagnosing and caring for patients in whom tuberculosis is clinically suspected. We collected 129 FFPE specimens, including 56 nontuberculosis cases, 63 MTB cases, and 10 nontuberculous mycobacteria (NTM) cases determined by acid-fast bacilli (AFB) culture. We performed AFB staining; nested MTB PCR, targeting the IS6110 gene; and real-time MTB PCR, targeting the senX3-regX3 intergenic region in the 129 FFPE specimens. The sensitivity and specificity of AFB staining were 37.0% and 98.2%, respectively, using AFB culture results as the reference standard. The sensitivity and specificity of detecting MTB were 68.3% and 98.5%, respectively, by nested PCR; and 74.6% and 98.5% by real-time PCR, respectively. Among the 129 specimens, four were positive by AFB staining but negative by nested or real-time PCR. NTM grew in all four of these cases by AFB culture. AFB density in FFPE tissue sections significantly correlated with MTB DNA load. Thus, real-time PCR is a useful diagnostic tool for rapid and sensitive MTB detection in FFPE specimens, whereas NTM should be included in differential diagnoses of cases positive by AFB staining but negative by PCR.     

Evaluation of the T-SPOT.TB test,oxidation-related factors,and antimicrobial peptide LL-37 in the diagnosis of pulmonary tuberculosis with type 2 diabetes

ObjectiveTo investigate the diagnostic value of the T cell spot (T-SPOT.TB) test, oxidation-related factors (ORF), and antimicrobial peptide LL-37 in patients with pulmonary tuberculosis (PTB) with type 2 diabetes.MethodsA total of 560 patients with PTB admitted to our hospital from January 2019 to April 2021 were retrospectively included in this study. Of these, 232 patients with PTB and type 2 diabetes were assigned to the combined group, and 328 patients without complications were assigned to the PTB group.ResultsAreas under the curve (AUCs) for the number of spot-forming cells in CFP10 and ESAT-6 test panels detecting PTB with type 2 diabetes were 0.892 (95% confidence interval [CI] 0.831–0.921) and 0.893 (95% CI 0.841–0.935), respectively. CFP10 combined with ESAT-6 had the highest diagnostic value, with sensitivity and specificity levels and an AUC of 87.73%, 88.93%, and 0.942 (95% CI 0.907–0.967), respectively. The levels of total antioxidant capacity, superoxide dismutase, and catalase in the combined group were lower than in PTB and control groups.ConclusionThe combination of T-SPOT.TB, ORF, and LL-37 in the diagnosis of pulmonary tuberculosis with type 2 diabetes mellitus has a high diagnostic value and clinical application value.     

Performance Comparison of GeneXpert MTB/RIF and ProbeTec ET Tests for Rapid Molecular Diagnosis of Extrapulmonary Tuberculosis in a Low TB/MDR-TB Incidence Country

ObjectiveThis study evaluated the performance of GeneXpert MTB/RIF (Xpert) and ProbeTec ET (PTec-ET) assays in diagnosing extrapulmonary tuberculosis (EPTB) in Kuwait.Materials and MethodsWe tested nonrespiratory clinical specimens (n = 3,995) collected from 3,995 patients suspected to have EPTB. These included cavitary fluids (n = 2,054), fine-needle aspirate (FNA)/pus/tissue biopsy (n = 1,461), urine (n = 302), cerebrospinal fluid (CSF, n = 118), and others (n = 60). All specimens were processed for acid-fast bacilli (AFB), culture in mycobacteria growth indicator tube 960 system, and nucleic acid detection by Xpert and PTec-ET according to manufacturer''s instructions.ResultsOf 3,995 specimens, 95 were AFB-positive, 403 were culture-positive, and an additional 86 samples had histopathology suggestive of TB. Using culture as reference, the sensitivity and specificity values were 88.33 and 97.3% for Xpert and 72.95 and 97.80% for PTec-ET, respectively. Although performance of both tests was comparable in AFB-positive samples, Xpert detected significantly more cases in culture-positive samples. Among culture-negative samples, Xpert detected 18 more cases including 16 with histopathological evidence of TB. Lowest positivity was detected for both tests in cavitary fluids. Xpert performed better than PTec-ET in culture-positive FNA/pus/tissue biopsy and CSF samples.ConclusionsAlthough performance of both tests was suboptimal for AFB-negative/culture-positive samples, Xpert performed better than PTec-ET and also detected more cases of AFB-negative/culture-negative/histopathology-positive samples. PTec-ET was positive in 3, while Xpert was positive in all 6 culture-positive CSF specimens for rapid diagnosis of TB meningitis. Xpert was thus superior to PTec-ET or smear microscopy in rapid diagnosis of EPTB.     

Utility of a combination of RD1 and RD2 antigens as a diagnostic marker for tuberculosis

We evaluated the diagnostic potential of a cocktail of 4 antigens encoded by regions of difference (RD) 1 and 2 of Mycobacterium tuberculosis, that is, early secretory antigenic target-6, culture filtrate protein-10 (CFP-10), CFP-21, and mycobacterial protein from species tuberculosis-64 (MPT-64) on the basis of antigen and antibody detection by enzyme-linked immunosorbent assay. Parallel detection of antigens and antibodies in the serum samples of pulmonary tuberculosis (PTB) patients resulted in higher sensitivity as compared to either of the single tests in both smear-positive (90%) and smear-negative (60%) PTB patients. In addition, combined detection of antigens and antibodies in the fluids of extrapulmonary tuberculosis (EPTB) patients could detect >90% of the patients with high specificity. These results demonstrate the ability of the combination of antigen and antibody detection assays based on the cocktail of RD antigens to diagnose a substantial number of PTB and EPTB cases with high specificity.     

径向超声支气管镜联合快速现场评估在细菌学阴性肺结核诊断中的应用

目的 评估径向超声支气管镜活检(EBUS-GS-TBLB)联合快速现场评估(ROSE)对细菌学阴性肺结核诊断的价值.方法 根据临床症状、影像学图像、痰细菌学结果(痰涂片和结核分枝杆菌培养)及首次分子生物学检查结果,收集2020年1月-12月疑似肺结核患者70例,随机分入A组(EBUS-GS-TBLB)34例和B组(EB...     

Reduction in turnaround time for laboratory diagnosis of pulmonary tuberculosis by routine use of a nucleic acid amplification test

Every first diagnostic specimen from suspected patients with pulmonary TB was tested by a nucleic acid amplification test (NAAT) to determine the reduction in turnaround time (TAT) for detecting Mycobacterium tuberculosis (MTB) that was possible under normal laboratory operating conditions. NAAT (Gen-Probe Mycobacterium tuberculosis Direct Testtrade mark) was performed on the first specimen and liquid culture (BACTEC 460), solid culture (Lowenstein-Jensen [LJ] agar and selective 7H11 [7H11S] agar), and fluorescent acid-fast bacilli (AFB) smear were performed on all 3 specimens from each patient. Eighty-one (10.2%) of 797 patients tested were diagnosed with pulmonary TB. The sensitivity of NAAT, BACTEC, LJ, 7H11S, and smear for the first specimen was 90%, 85%, 67%, 53%, and 58%, respectively, whereas the sensitivity for the series of 3 specimens was 90%, 95%, 74%, 74%, and 70%, respectively. Positive predictive value was 100% for all tests except AFB smear, which was 79%. The time to detect 75% of all TB cases was 4 days for NAAT and 21 days for liquid culture; other tests had a sensitivity of less than 75%. Identification and testing every first diagnostic specimen by NAAT has the potential to reduce the overall TAT for laboratory TB diagnosis by approximately 2 weeks.     

Performance of the Gen-Probe amplified Mycobacterium tuberculosis direct test in a laboratory that infrequently isolates Mycobacterium tuberculosis

The performance of the Gen-Probe Mycobacterium tuberculosis direct (MTD) test was assessed in a laboratory whose specimens were derived from a population with a low prevalence (1.3%) of tuberculosis. A total of 339 specimens from 113 patients were included in the study. Nine of 10 MTD positive samples were culture positive (smear positive n = 7; smear negative, n = 1; smear not ordered, n = 2). The 10th MTD-positive sample, which was smear and culture negative, was from a patient whose two other study specimens were smear and culture positive and who had a clinical history consistent with tuberculosis. Prior to and following resolution of discrepant results, the sensitivities and specificities of the MTD test relative to culture were 100 and 99.7% and 100 and 100%, respectively.     

Probe-to-bone test for diagnosing diabetic foot osteomyelitis: reliable or relic?

OBJECTIVE: We sought to assess the accuracy of the probe-to-bone (PTB) test in diagnosing foot osteomyelitis in a cohort of diabetic patients with bone culture proven disease. RESEARCH DESIGN AND METHODS: In this 2-year longitudinal cohort study, we enrolled 1,666 consecutive diabetic individuals who underwent an initial standardized detailed foot assessment, followed by examinations at regular intervals. Patients were instructed to immediately come to the foot clinic if they developed a lower-extremity complication. For all patients with a lower-extremity wound, we compared the results of the PTB test with those of a culture of the affected bone. We called PTB positive if the bone or joint was palpable and defined osteomyelitis as a positive bone culture. RESULTS: Over a mean of 27.2 months of follow-up, 247 patients developed a foot wound and 151 developed 199 foot infections. Osteomyelitis was found in 30 patients: 12% of those with a foot wound and 20% in those with a foot infection. When all wounds were considered, the PTB test was highly sensitive (0.87) and specific (0.91); the positive predictive value was only 0.57, but the negative predictive value was 0.98. CONCLUSIONS: The PTB test, when used in a population of diabetic patients with a foot wound among whom the prevalence of osteomyelitis was 12%, had a relatively low positive predictive value, but a negative test may exclude the diagnosis.     

血管压迫性三叉神经痛的3D-TOF-MRA序列磁共振成像与手术结果对照

目的探讨3D-TOF-MRA序列对血管压迫性三叉神经痛的诊断价值,并分析其MRI表现。方法回顾性分析26例三叉神经痛患者MRI表现及手术结果。结果3D-TOF-MRA序列显示三叉神经脑池段清晰14例,发现责任小动脉18条,与三叉神经接触16条,压迫2条;三叉神经显示欠清晰12例,发现责任小动脉18条。术中证实责任血管共48条,小动脉38条,静脉10条。3D-TOF-MRA序列显示责任血管的阳性率为75%,其中小动脉为95%,静脉为0。结论3D-TOF-MRA序列能清晰显示小动脉压迫性三叉神经痛的责任血管,并具有较高的阳性率,对提供患者术前评估和指导治疗具有极其重要的意义。