Solitary pulmonary nodules: dynamic contrast-enhanced MR imaging--perfusion differences in malignant and benign lesions

PURPOSE: To determine whether dynamic contrast material-enhanced magnetic resonance (MR) imaging with use of kinetic and morphologic parameters reveals statistically significant differences between malignant and benign solitary pulmonary nodules. MATERIALS AND METHODS: Fifty-eight patients met the inclusion criteria of a solitary 5-40-mm pulmonary nodule without calcification or fat at computed tomography. Fifty-one patients were examined successfully; 46 received a histologic diagnosis, and five received a diagnosis by means of observation over 2 years. Dynamic MR images were acquired every 10 seconds for a total of 4 minutes. Diagnostic characteristics for differentiation were examined by using threshold values for maximum peak enhancement, slope of enhancement, and washout. Receiver operating characteristic curves were calculated to test the usefulness of these parameters. The diagnostic performance of a combination of curve profiles and morphologic contrast material distribution were tested by using a decision tree. RESULTS: Frequency of malignancy was 53% (27 of 51 nodules). Malignant nodules showed stronger enhancement with a higher maximum peak and a faster slope (P <.001). Significant washout (>0.1% increase in signal intensity per second) was found only in malignant lesions (14 of 27 lesions). Sensitivity, specificity, and accuracy were 96%, 88%, and 92%, respectively, for maximum peak; 96%, 75%, and 86% for slope; and 52%, 100%, and 75% for washout. When curve profiles and morphologic enhancement patterns were combined, sensitivity increased to 100%. CONCLUSION: Dynamic MR imaging delineates significant kinetic and morphologic differences in vascularity and perfusion between malignant and benign solitary pulmonary nodules. Washout seems to be highly specific for malignancy.     

Solitary pulmonary nodules: optimal slice thickness of high-resolution CT in differentiating malignant from benign

The purpose of this study was to determine an optimal slice thickness that was efficient in differentiating malignant from benign solitary pulmonary nodules (SPNs) on high-resolution computed tomography (HRCT) images. For a total of 92 SPNs, four radiologist indicated their confidence level for the malignant or benign SPN on the CT images presented in 1-, 3-, and 5-mm slice thickness. HRCT could be used to differentiate more accurately the malignant nodules from the benign ones using 1-mm-thick sections than 3- or 5-mm-thick sections.     

HRCT常见恶性征象对孤立性肺结节的定性诊断

目的：探讨良、恶性孤立肺结节（SPN）部分常见 HRCT 征象的发生率及意义。方法：回顾性分析经手术病理证实的129例 SPN（其中88例为恶性,41例为良性）的 HRCT 图像,采用双盲法阅片,观察指标包括短毛刺征、深分叶征和血管集束征,分析、记录上述征象出现的数量。将无上述3种征象的 SPN 纳入 A 组,仅具有其中1种征象的 SPN 为 B组,具有2种上述征象的 SPN 为 C 组,具有3种上述征象的 SPN 为 D 组。计算在恶性 SPN 和良性 SPN 中,A、B、C、D 四种情况的出现率并进行统计学分析。结果：A 情况在恶性 SPN 中的出现率为2．2％（2／88）,在良性 SPN 中为53．7％（22／41）,在良、恶性组间差异有极显著性意义（P ＜0．001）;B 情况在恶性 SPN 中的出现为23．9％（21／88）,在良性 SPN 中为26．8％（11／41）,良、恶性组间差异无显著性意义（P ＞0．05）;C 情况在恶性 SPN 中的出现率为30．7％（27／88）,在良性SPN 中为12．2％（5／41）,良、恶性组间差异有显著性意义（P ＜0．05）;D 情况在恶性 SPN 中的出现率为43．2％（38／88）,在良性 SPN 中比7．3％（7／41）,良、恶性组间差异有极显著意义（P ＜0．001）。结论：HRCT 常见恶性征象组合出现对于恶性 SPN 的定性诊断意义大于单独出现或不出现。     

Solitary pulmonary nodules: Part II. Evaluation of the indeterminate nodule.

Various strategies may be used to evaluate indeterminate solitary pulmonary nodules. Growth rate assessment is an important and cost-effective step in the evaluation of these nodules. Clinical features (eg, patient age, history of prior malignancy, presenting symptoms, smoking history) can be useful in suggesting the diagnosis and aiding in management planning. Bayesian analysis allows more precise determination of the probability of malignancy (pCa). Decision analysis models suggest that the most cost-effective management strategy depends on the pCa for a given nodule. At contrast material-enhanced computed tomography, nodular enhancement of less than 15 HU is strongly predictive of a benign lesion, whereas enhancement of more than 20 HU typically indicates malignancy. At 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography, lesions with low FDG uptake are typically benign, whereas those with increased FDG uptake are typically malignant. Results of transthoracic needle aspiration biopsy influence management in approximately 50% of cases and, in indeterminate lesions with a pCa between 0.05 and 0.6, is the best initial diagnostic procedure. It is optimally used in peripheral nodules and has been reported to establish a benign diagnosis in up to 91% of cases. Although there is no one correct management approach, the ability to distinguish benign from malignant solitary pulmonary lesions has improved with the use of these strategies.     

Computer-aided differentiation of malignant from benign solitary pulmonary nodules imaged by high-resolution CT

We investigated the possibility of using computer analysis of high-resolution CT images to radiologically classify the shape of pulmonary nodules. From a total of 107 HRCT images of solid, solitary pulmonary nodules with prior differentiation as benign (n=55) or malignant (n=52), we extracted the desired pulmonary nodules and calculated two quantitative parameters for characterizing nodules: circularity and second central moment. Using discriminant analysis for two thresholds in differentiating malignant from benign states resulted in a sensitivity of 76.9%, a specificity of 80%, a positive predictive value of 78.4%, and a negative predictive value of 78.6%.     

甲状腺良恶性结节的超声鉴别诊断

目的探讨甲状腺良恶性结节声像图表现及鉴别诊断。方法对经手术病理证实的60例甲状腺良性结节和21例恶性结节的超声二维及彩色多普勒血流声像图（CDFI）表现进行对比分析。结果良恶性结甲在形态,边界,内部回声,彩色血流分布,阻力指数,颈部淋巴结肿大等指标有统计学显著性差异。结论形态不规整,边界不清,内部不均匀低回声,微钙化,内部血流丰富而周边少或无血流,RI〉0．7等可以作为恶性结节的主要指标;不清晰、不完整、宽窄不一的晕环及颈部淋巴结肿大高度提示恶性;囊性结节可作为排除恶性指标。微小乳头状癌结节及良恶性并发的多源性结节常常会被误诊。     

Diagnostic performance of PET/CT in differentiation of malignant and benign non-solid solitary pulmonary nodules

OBJECTIVE: To evaluate whether [F-18] fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) can distinguish benign from malignant solitary pulmonary nodules (SPNs) with non-solid components. METHODS: [F-18] FDG-PET/CT scans were performed on 53 consecutive patients (30 men, 23 women; mean age 65 years) who had SPNs with non-solid components identified by CT screening for lung cancer. All patients underwent surgical resection, and all lesions were pathologically proved. Visual score, maximal, and mean standardized uptake value (SUV), and maximal and mean lesion-to-normal tissue count density ratio (LNR) were calculated in all lesions. In addition, clinical characteristics, laboratory test results, and CT findings were assessed. RESULTS: Benign SPNs with non-solid components had a higher uptake on [F-18] FDG-PET/CT. Visual score, maximal and mean SUV, and maximal and mean LNR were significantly higher in the benign when compared with the malignant SPNs (P < 0.001). When the cutoff of 1.5 was assigned for maximal SUV, the diagnostic performance of [F-18] FDG-PET/CT in predicting benign SPN revealed 100.0% sensitivity, 96.4% specificity, and 100.0% accuracy. CONCLUSIONS: [F-18] FDG-PET/CT is useful for the differential diagnosis of SPNs with non-solid components.     

Solitary pulmonary nodules: CT assessment

Computed tomography (CT) was used to examine 634 solitary pulmonary nodules (SPNs). Each lesion was assessed as benign or indeterminate on the basis of CT criteria. Benign nodules made up 44% of all SPNs and 58% of the 431 that were 2 cm or less in diameter. All malignant SPNs were assessed as indeterminate, and adenocarcinoma (42%) was the most common primary malignancy. A total of 176 (63% of benign SPNs) were correctly assessed as benign by CT. Ninety SPNs assessed as diffusely calcified were not so identified by conventional tomography at outside institutions. An SPN can be reliably assessed by CT as benign if it exhibits high attenuation values, exceeding a critical level and distributed diffusely throughout a CT section through the center of the lesion and a well-defined edge. Although 38 of 283 (13.4%) primary lung cancers contained localized calcification, there was no significant overlap with the diffuse calcification of benign lesions. Central carcinoid tumors may contain focal ossification, but such lesions may be recognized by noting the proximity of larger bronchi. Assessment of SPNs by CT is most effective for lesions 2.0 cm or less in diameter. For larger lesions, the frequency of benign disease was decreased (14.3% of 203), as was the percentage of benign SPNs correctly assessed as benign by CT (37.9%).     

Usefulness of morphological characteristics for the differentiation of benign from malignant solitary pulmonary lesions using HRCT

The aim of this study was to analyze different characteristics on high-resolution computed tomography (HRCT) that help differentiate benign solitary pulmonary lesions (BSPLs) from malignant solitary pulmonary lesions (MSPLs). High-resolution computed tomography was performed on 104 consecutive patients with SPLs. The whole lesion was examined with a slice thickness of 1 mm and a 12-cm field of view. All lesions were surgically excised within 24 h of the CT examination. Satellite nodules, cavitations, and necrosis were found only in MSPLs. Useful characteristics for the differentiation of BSPLs from MSPLs were the presence of spicules (p < 0.00005), spicules extending to the visceral pleura (p < 0.0005), the vessel sign (p < 0.0005), pleural retraction (p < 0.001), circumscribed pleural thickening (p < 0.001), the bronchus sign (p < 0.005), the presence of ground-glass attenuation adjacent to the SPL (p < 0.01), the density of the lesion (p < 0.05), and the length of spicules (p < 0.05). Using the significant characteristics p < 0.01 for the identification of MSPLs, a sensitivity of 91.4 % and a specificity of 56.5 % (accuracy of 83.7 %) was found. A precise morphological assessment of the periphery of the pulmonary lesion is necessary. The HRCT technique is useful in differentiation of BSPLs from MSPLs. However, metastases strongly resembled benign lesions in terms of size and edge type, and chronic inflammatory pseudotumors as a group mimic MSPLs. Received: 21 April 1998; Revision received: 28 September 1998; Accepted: 6 November 1998     

影像组学分析和机器学习在肺结节良恶性分类中的应用

目的:探讨CT纹理特征对良恶性肺结节的鉴别价值及在独立数据集上的泛化能力.方法:回顾性分析LIDC-IDRI和LUNGx数据库中共1428个肺结节(直径3～30 mm)的CT图像,其中良性1221个、恶性207个.将LIDC-IDRI数据库的1372个结节(良性1190个,恶性182个)作为训练集,LUNGx数据库的5...     

Critical evaluation of the specificity of MRI and TVUS for differentiation of malignant from benign adnexal lesions

The aim of our work was to study the specificity of MRI in comparison with transvaginal US for differentiation of malignant from benign adnexal lesions. A total of 67 patients with clinically suspicious adnexal lesions were evaluated by MRI. Transaxial and coronal images were acquired using T1-weighted sequences before and following IV contrast and T2-weighted sequences. In all patients transvaginal ultrasound examinations (TVUS) were performed. For both imaging modalities each lesion was classified separately as either benign or malignant according to previously published criteria. Pathologic findings were available in 65 cases. Both MRI and TVUS correctly classified the 12 malignant lesions (sensitivity 100 %). Specificity (MRI: 78.2 %, TVUS: 65.5 %) and accuracy (MRI: 82 %, TVUS: 71.6 %) were higher with MRI than with TVUS, but differences were statistically not significant (p = 0.18 and p = 0.20, chi-square test). There was agreement/disagreement between findings of MRI and US in 52/15 lesions. The macroscopic criteria for malignancy are unspecific and result in a limitation of the specificity of both MRI and TVUS. The MRI technique is a valuable adjunct to TVUS by enabling further clarification of adnexal tumors with equivocal complex or solid vaginal sonographic findings. Received 6 December 1996; Revision received 17 March 1997; Accepted 9 April 1997     

超声造影鉴别甲状腺良恶性结节的价值

目的应用超声造影观察甲状腺良恶性结节血流灌注特征,探讨超声造影鉴别甲状腺良恶性结节的价值。方法对28例患者28个甲状腺结节行超声造影检查,观察甲状腺结节超声造影增强特征,应用Qontraxt定量分析软件对甲状腺良恶性结节血流灌注特征进行时间-强度曲线分析。定量参数包括峰值强度(Peak)、达峰时间(TP)、曲线尖度(Sharpness)及曲线下面积(AUC)。结果①甲状腺良性结节造影后多边界清晰,形态规则,以低强化多见。②甲状腺恶性结节造影后多边界不清,形态欠规则,以等强化及低强化为主。③甲状腺良恶性结节的强化类型差异无统计学意义(P>0.05),具有一定的重叠性。环状强化更多出现在良性结节中。④甲状腺恶性结节达峰时间短于良性结节,曲线尖度、曲线下面积高于良性结节,差异有统计学意义(P<0.05)。结论甲状腺良、恶性结节的超声造影增强特征及时间-强度曲线存在一定的重叠性,但其与结节的病理生理密切相关,可以为甲状腺结节良恶性的鉴别提供有效的、补充性信息,有一定的诊断价值。     

Computer-aided diagnosis for the differentiation of malignant from benign thyroid nodules on ultrasonography

RATIONALE AND OBJECTIVES: We sought to evaluate the diagnostic performance of an artificial neural network (ANN) and binary logistic regression (BLR) in differentiating malignant from benign thyroid nodules on ultrasonography. MATERIALS AND METHODS: Two experienced radiologists, who were unaware of the histopathological diagnosis, analyzed ultrasonographic (US) features of 109 pathologically proven thyroid lesions (49 malignant and 60 benign) in 96 patients. Each radiologist was asked to evaluate US findings and categorize nodules into one of the two groups (malignant vs. benign) in each case. The following 8 US parameters were assessed for each nodule: size, shape, margin, echogenicity, cystic change, microcalcification, macrocalcification, and halo sign. Statistically significant US findings were obtained with backward stepwise logistic regression and were used for training and testing of the ANN and the BLR. The performance of the ANN and BLR was compared to that of the radiologists using receiver-operating characteristic (ROC) analysis. RESULTS: Statistically significant US findings were size, margin, echogenicity, cystic change, and macrocalcification of the nodules. The area under the ROC curve (Az) values of ANN and BLR were 0.9492 +/- 0.0195 and 0.9046 +/- 0.0289, respectively. The Az value was 0.8300 +/- 0.0359 for reader 1 and 0.7600 +/- 0.0409 for reader 2. The Az values for ANN and BLR were significantly higher than those for both radiologists (all p < .05). CONCLUSION: The performance of the ANN and the BLR was better than that of the radiologists in the distinction of benign and malignant thyroid nodules.