Predictors for benign solitary pulmonary nodule in tuberculosis-endemic area

Nondiagnostic, radial-probe endobronchial ultrasound-guided biopsy for peripheral lung lesions: The added value of radiomics from ultrasound imaging for predicting malignancy

OBJECTIVES

This study investigated whether radiomic features extracted from radial-probe endobronchial ultrasound (radial EBUS) images can assist in decision-making for subsequent clinical management in cases with indeterminate pathologic results.

METHODS

A total of 494 patients who underwent radial EBUS biopsy for lung nodules between January 2017 and December 2018 were allocated to our training set. For the validation set, 229 patients with radial EBUS biopsy results from January 2019 to April 2020 were used. A multivariate logistic regression analysis was used for feature selection and prediction modeling.

RESULTS

In the training set, 157 (67 benign and 90 malignant) of 212 patients pathologically diagnosed as indeterminate were analyzed. In the validation set, 213 patients were diagnosed as indeterminate, and 158 patients (63 benign and 95 malignant) were included in the analysis. The performance of the radiomics-added model, which considered satellite nodules, linear arc, shape, patency of vessels and bronchi, echogenicity, spiculation, C-reactive protein, and minimum histogram, was 0.929 for the training set and 0.877 for the validation set, whereas the performance of the model without radiomics was 0.910 and 0.891, respectively.

CONCLUSION

Although the next diagnostic step for indeterminate lung biopsy results remains controversial, integrating various factors, including radiomic features from radial EBUS, might facilitate decision-making for subsequent clinical management.

Clinical and Computed Tomography (CT) Characteristics of Pulmonary Nodules Caused by Cryptococcal Infection

Purpose

To investigate the clinical and computed tomography (CT) characteristics of pulmonary nodules caused by cryptococcal infection and gain a greater insight and understanding that will reduce misdiagnosis.

Materials and Methods

A total of 47 patients with confirmed pulmonary cryptococcosis (PC) manifested as nodules were retrospectively enrolled from January 2013 to December 2020. The clinical and CT data of patients with single and multiple nodules were analyzed and compared with emphasis on exploring the characteristics of the solitary ones.

Results

Among the 47 patients, single and multiple nodules were detected in 25 (53.2%) and 22 (46.8%) patients, respectively, with similar clinical characteristics. The diameter of solitary nodules was smaller than that of the largest ones of the multiple nodules (P = 0.000). Compared with multiple nodules, less solitary nodules were located in the subpleural zone (P = 0.031) and had a cavity or vacuole (P = 0.049). Regarding the solitary nodules, 22 (88.0%) and 3 (12.0%) were solid and subsolid, respectively. Eighteen (81.8%) solid solitary nodules exhibited either one of air bronchogram or vacuole, satellite lesions, and halo sign. Twenty-three (92.0%) of 25 patients with solitary nodules had follow-up CT data, and most of them had no changes (12, 52.1%) or increased in size and/or density (8, 34.8%), but only a few (3, 13.0%) decreased with or without anti-inflammatory therapy.

Conclusion

The clinical characteristics of patients with solitary and multiple nodules caused by PC are similar. The solitary nodules are smaller, more scattered, but less necrotic than multiple ones. For solitary nodules with air bronchogram or vacuole, satellite lesions, or halo sign, PC should be considered as one of the differential diagnosis.

Discriminating Small-Sized (2 cm or Less), Noncalcified, Solitary Pulmonary Tuberculoma and Solid Lung Adenocarcinoma in Tuberculosis-Endemic Areas

Background. Pulmonary tuberculoma can mimic lung malignancy and thereby pose a diagnostic dilemma to clinicians. The purpose of this study was to establish an accurate, convenient, and clinically practical model for distinguishing small-sized, noncalcified, solitary pulmonary tuberculoma from solid lung adenocarcinoma. Methods. Thirty-one patients with noncalcified, solitary tuberculoma and 30 patients with solid adenocarcinoma were enrolled. Clinical characteristics and CT morphological features of lesions were compared between the two groups. Multivariate logistic regression analyses were applied to identify independent predictors of pulmonary tuberculoma and lung adenocarcinoma. Receiver operating characteristic (ROC) analysis was performed to investigate the discriminating efficacy. Results. The mean age of patients with tuberculoma and adenocarcinoma was 46.8 ± 12.3 years (range, 28–64) and 61.1 ± 9.9 years (range, 41–77), respectively. No significant differences were observed concerning smoking history and smoking index, underlying disease, or tumor markers between the two groups. Univariate and multivariate analyses showed age and lobulation combined with pleural indentation demonstrated excellent discrimination. The sensitivity, specificity, accuracy, and the area under the ROC curve were 87.1%, 93.3%, 90.2%, and 0.956 (95% confidence interval (CI), 0.901–1.000), respectively. Conclusion. The combination of clinical characteristics and CT morphological features can be used to distinguish noncalcified, solitary tuberculoma from solid adenocarcinoma with high diagnostic performance and has a clinical application value.

Unexpected exposure to Mycobacterium tuberculosis during bronchoscopy using radial probe endobronchial ultrasound

BACKGROUND

Bronchoscopy using radial probe endobronchial ultrasound (EBUS) is performed when a peripheral lung lesion (PLL) is suspected to be malignant. However, pulmonary tuberculosis is diagnosed in some patients, and healthcare workers could therefore be exposed to tuberculosis if sufficient precautions are not taken. In this study, we examined the proportion of and factors associated with unexpected exposure to Mycobacterium tuberculosis during bronchoscopy using radial probe EBUS.

METHODS

This retrospective study included 970 patients who received bronchoscopy using radial probe EBUS between December 2015 and November 2018. Clinical, histological, radiological, and microbiological data were reviewed.

RESULTS

Pulmonary tuberculosis was diagnosed in 31 patients (3.2%) during bronchoscopy using radial probe EBUS. Patients with a lower age were significantly more likely to be diagnosed with tuberculosis than elderly patients (odds ratio [OR], 0.951; 95% confidence interval [CI], 0.924-0.978; P = 0.001). Among the various CT findings, a low HUs difference between pre- and post-enhanced CT (OR, 0.976; 95% CI, 0.955-0.996; P = 0.022), the presence of concentric cavitation (OR, 5.211; 95% CI, 1.447-18.759; P = 0.012), and the presence of satellite centrilobular nodules (OR, 22.925; 95% CI, 10.556-49.785; P < 0.001) were independently associated with diagnosis of tuberculosis.

CONCLUSIONS

The proportion of unexpected exposure to Mycobacterium tuberculosis during bronchoscopy using radial probe EBUS was 3.2%. A higher risk was independently associated with a younger age and CT findings of a small difference in HUs between pre- and post-enhancement images, concentric cavitation, and the presence of a satellite centrilobular nodule.

Predicting the Risk of Malignancy of Lung Nodules Diagnosed as Indeterminate on Radial Endobronchial Ultrasound-Guided Biopsy

The next diagnostic step in cases of indeterminate radial probe endobronchial ultrasound (radial EBUS)-guided biopsy results remains uncertain. This study aimed to identify risk factors for malignancy based on clinical findings, chest computed tomography (CT), and radial EBUS images, and to estimate the risk of malignancy in lung nodules that showed indeterminate radial EBUS-guided biopsy results by constructing a nomogram. This retrospective study included 157 patients with indeterminate results on an initial radial EBUS biopsy performed at the Samsung Medical Center from January 2017 to December 2018, but with a definitive final diagnosis. Medical records, chest CT, radial EBUS images, and the final diagnoses were reviewed. Patients were randomly divided into training and validation sets. Factors related to malignancy were identified through logistic regression analysis, and a nomogram was constructed using the training set and subsequently applied to the validation set. Six factors in univariable and multivariable analyses, including upper lobe location, spiculation, satellite nodules, echogenicity, presence of dots or linear arcs, and patency of vessels and bronchi predicted malignancy. A nomogram was constructed based on these predictors. The area under the curve (AUC) value of the nomogram was 0.858 using the chest CT factors, which improved to 0.952 when radial EBUS factors were added. The calibration curve showed good agreement between the actual and nomogram-predicted malignancy outcomes. The utility of radial EBUS images for revealing risk factors of malignancy was confirmed. Furthermore, our nomogram was able to predict the probability of malignancy in lung nodules with indeterminate radial EBUS-guided biopsy results.

A prediction model to evaluate the pretest risk of malignancy in solitary pulmonary nodules: evidence from a large Chinese southwestern population

PURPOSE

Lung cancer is the leading cause of cancer death and there have been clinical prediction models. This study aimed to evaluate the diagnostic performance of published models and create new models to evaluate the probability of malignant solitary pulmonary nodules (SPNs) in Chinese population.

METHODS

We consecutively enrolled 2061 patients with SPNs from West China Hospital between January 2008 and December 2016, each SPN was pathologically confirmed. First, four published prediction models, Mayo clinic model, Veterans Affairs (VA) model, Brock model and People's Hospital of Peking University (PEH) model were validated in our patients. Then, utilizing logistic regression, decision tree and random forest (RF), we developed three new models and internally validated them.

RESULTS

Area under the receiver operating characteristic curve (AUC) values of four published models were as follows: Mayo 0.705 (95% CI 0.658-0.752, n = 726), VA 0.64 6 (95% CI 0.598-0.695, n = 800), Brock 0.575 (95% CI 0.502-0.648, n = 550) and PEH 0.675 (95% CI 0.627-0.723, n = 726). Logistic regression model, decision tree model and RF model were developed, AUC values of these models were 0.842 (95% CI 0.778-0.906), 0.734 (95% CI 0.647-0.821), 0.851 (95% CI 0.789-0.914), respectively.

CONCLUSION

The four published lung cancer prediction models do not apply to our population, and we have established new models that can be used to predict the probability of malignant SPNs.

Surgical resection is sufficient for incidentally discovered solitary pulmonary nodule caused by nontuberculous mycobacteria in asymptomatic patients

Incidentally discovered solitary pulmonary nodules (SPN) caused by nontuberculous mycobacteria (NTM) is uncommon, and its optimal treatment strategy remains uncertain. This cohort study determined the clinical characteristics and outcome of asymptomatic patients with NTM-SPN after surgical resection. Resected SPNs with culture-positive for NTM in six hospitals in Taiwan during January, 2010 to January, 2017 were identified. Asymptomatic patients without a history of NTM-pulmonary disease (PD) or same NTM species isolated from the respiratory samples were selected. All were followed until May 1, 2019. A total of 43 patients with NTM-SPN were enrolled. Mycobacterium avium complex (60%) and M. kansasii (19%) were the most common species. The mean age was 61.7 ± 13.4. Of them, 60% were female and 4% had history of pulmonary tuberculosis. The NTM-SPN was removed by wedge resection in 38 (88%), lobectomy in 3 (7%) and segmentectomy in 2 (5%). Caseating granuloma was the most common histologic feature (58%), while chronic inflammation accounts for 23%. Mean duration of the follow-up was 5.2 ± 2.8 years (median: 4.2 years [2.5–7.0]), there were no mycobacteriology recurrence or NTM-PD development. In conclusion, surgical resection is likely to curative for incidentally discovered NTM-SPN in asymptomatic patients without culture evidence of the same NTM species from respiratory specimens, and routine mycobacterium culture for resected SPN might be necessary for differentiating pulmonary tuberculosis and NTM because further treatment differs.

HIV-infected patients with opportunistic pulmonary infections misdiagnosed as lung cancers: the clinicoradiologic features and initial application of CT radiomics

Background

To characterize clinicoradiologic and radiomic features for identifying opportunistic pulmonary infections (OPIs) misdiagnosed as lung cancers in patients with human immunodeficiency virus (HIV).

Methods

Twenty-four HIV-infected patients who were misdiagnosed with lung cancers on CT images and had OPIs confirmed by pathological examination or integration of clinical and laboratory findings and 49 HIV-infected patients with lung cancers confirmed pathologically were included. Semiautomated segmentation of the lesion was implemented with an in-house software. The lesion boundary was adjusted manually by radiologists. A total of 99 nonenhanced-CT-based radiomic features were then extracted with PyRadiomics. The clinicoradiologic and radiomic features were compared between the OPI and cancer groups.

Results

In the OPI group, 19 patients (79.2%) had tuberculosis (TB) infections, 2 (8.3%) had nontuberculosis mycobacterium (NTM) infections, 2 (8.3%) had cryptococcus infections and 1 (4.2%) had a mixed infection of TB and NTM. There were significant differences in age, proportion of smokers, smoking index, highly active antiretroviral therapy (HAART) duration, CD4⁺ counts and CD4⁺/CD8⁺ ratio between the two groups (P=0.000, 0.012, 0.007, 0.002, 0.000, and 0.000, respectively). In peripheral-type lesions, the presence of pleural indentation was less common, and the presence of satellite lesions was more common in the OPI group (P=0.016 and 0.020, respectively). Four radiomic parameters of central-type lesions were significantly different, including large dependence high gray level emphasis (LDHGLE), skewness, inverse difference normalized (IDN) and kurtosis (P=0.008, 0.017, 0.017, and 0.017, respectively). However, neither CT features of central-type lesions nor radiomic parameters of peripheral-type lesions were significantly different between the two groups.

Conclusions

Clinicoradiologic features together with radiomics may help identify OPIs mimicking lung cancers in HIV-infected patients.

Factors affecting bacterial culture positivity in specimens from bronchoscopy in patients with suspected lung cancer

BACKGROUND

Bronchoscopy is important to diagnose lung cancer. However, some patients who undergo bronchoscopic procedures develop respiratory tract infections. Little is known about the proportion of pathogen-positive results in bacterial cultures from diagnostic bronchoscopy samples in patients with suspected lung cancer. This study aimed to determine the rate of positive bacterial cultures after diagnostic bronchoscopy in patients with suspected lung cancer and the relationship among culture results, clinical characteristics, and respiratory tract infections.

METHODS

We retrospectively reviewed the medical records of all immunocompetent patients who underwent bronchoscopy and had culture and histological samples for the diagnosis of peripheral pulmonary lesions from September 2012 to August 2014 at the National Cancer Center in Tokyo. We analyzed data and classified radiological lesions into the following categories: calcifications, cavitations, low-density areas, margin irregularities, and satellite nodules.

RESULTS

The study population consisted of 328 patients (median age, 69 years). We found that 65.9% of patients had malignant lesions and 4.2% of patients had positive cultures for pathogenic bacteria. The number of calcifications (p = 0.002, 95% CI: 2.17-41.10) was significantly higher in patients with positive bacterial isolates, according to the multivariate analysis, and bacterial culture positivity was not associated with the development of respiratory complications after bronchoscopy. Of the three patients with respiratory complications, all presented with cavitations.

CONCLUSION

Because of the low prevalence of positive bacterial cultures in patients with suspected lung cancer, bacterial culture may be limited to specific patients, such as those with calcifications. Lesions with cavitation warrant close monitoring.

Computed Tomography Imaging Findings of Pulmonary Chondroma

PURPOSE

To characterize the computed tomography (CT) imaging findings in patients with pulmonary chondroma.

METHODS

We examined CT imaging findings of eight patients with histopathologically verified pulmonary chondroma. We assessed the location, size, shape, margins, amount of calcification, calcification pattern, and attenuation on precontrast and enhancement CT.

RESULTS

All patients exhibited solitary, mildly lobulated pulmonary masses, which were located in the right lung in four cases and the left lung in four cases. The mean lesion size was 3.7 cm (range 0.9-10.7 cm). All eight tumours had a well-defined margin. On plain CT images, seven of the cases (87.5%) showed a mass with varying degrees of calcification, which included strip-like punctate (n=5) and ring (n=2) patterns. One patient with a large lesion (10.7 cm) showed chest wall adhesion. On contrast-enhanced CT images, all lesions demonstrated slight inhomogeneous enhancement ≤14 HU.

CONCLUSION

CT is the reference standard diagnostic technique for locating pulmonary chondroma. In most cases, CT findings show some characteristics that are important in the diagnosis, surgical planning, and follow-up of the tumour.

A retrospective validation study of three models to estimate the probability of malignancy in patients with small pulmonary nodules from a tertiary oncology follow-up centre

AIM

To estimate the probability of malignancy in small pulmonary nodules (PNs) based on clinical and radiological characteristics in a non-screening population that includes patients with a prior history of malignancy using three validated models.

MATERIALS AND METHODS

Retrospective data on clinical and radiological characteristics was collected from the medical records of 702 patients (379 men, 323 women; range 19-94 years) with PNs ≤12 mm in diameter at a single centre. The final diagnosis was compared to the probability of malignancy calculated by one of three models (Mayo, VA, and McWilliams). Model accuracy was assessed by receiver operating characteristics (ROC). The models were calibrated by comparing predicted and observed rates of malignancy.

RESULTS

The area under the ROC curve (AUC) was highest for the McWilliams model (0.82; 95% confidence interval [CI]: 0.78-0.91) and lowest for the Mayo model (0.58; 95% CI: 0.55-0.59). The VA model had an AUC of (0.62; 95% CI: 0.47-0.64). Performance of the models was significantly lower than that in the published literature.

CONCLUSIONS

The accuracy of the three models is lower in a non-screening population with a high prevalence of prior malignancy compared to the papers that describe their development. To the authors' knowledge, this is the largest study to validate predictive models for PNs in a non-screening clinically referred patient population, and has potential implications for the implementation of predictive models.

Pulmonary chondroid hamartoma with nontuberculous mycobacterial infection: two case reports

Solitary pulmonary nodules (SPNs) can be manifested in a variety of disorders including neoplasms, infection, inflammation, and vascular or congenital abnormalities. In addition, they are often accompanied with other pulmonary pathologic lesions such as consolidations and several pulmonary disorders present as similar pulmonary nodular lesions simultaneously. Diagnostic workup is important for these SPNs; however, many physicians often miss the second diagnosis for multiple pulmonary lesions with SPNs due to lack of clinical suspicion that each pulmonary nodule or pathologic lesion can have each other's diagnosis. Herein, we report 2 cases of coexistence of pulmonary chondroid hamartoma with nontuberculous mycobacterial (NTM) infection presenting as pulmonary nodules and multiple consolidative lesions. A 60-year-old man was admitted for the evaluation of multifocal pulmonary lesions including SPN with chronic exertional dyspnea. Multiple lung tissues were obtained from each lesion through percutaneous transthoracic needle biopsy (PTNB). At the same time, bacteriologic examination was performed using respiratory samples obtained by bronchoscopy. Based on pathologic and microbiologic results, the patient diagnosed as pulmonary chondroid hamartoma with pulmonary NTM infectious disease. In addition, a 56-year-old woman visited for the evaluation of a small SPN. The SPN was resected surgically for the pathologic examination and turned out to be pulmonary chondroid hamartoma. Interestingly, the diagnostic workup revealed that the patient had Lady Windermere syndrome which is one of features for Mycobacterium avium complex (MAC) pulmonary disease. Both patients were treated with the standard antibiotics against MAC as recommended by the ATS/IDSA guideline. This is the first report of 2 patients, as far as we know, that chondroid hamartoma and NTM disease develop simultaneously in the lung. This report emphasizes that physicians should endeavor to confirm the individual diagnosis for the various pulmonary abnormal lesions detected at the same time, if necessary through multifocal biopsies for each lesion.

Differences in clinical presentation of non-small cell lung cancer in never-smokers versus smokers

OBJECTIVES

This study was conducted to evaluate whether or not tumor spread and the diagnostic process in non-small cell lung cancer (NSCLC) is different based on smoking history.

METHODS

Associations between smoking status and clinical presentation were evaluated controlling for the effect of histology. Lung cancer with delayed diagnosis (LCDD) and incidental detection (LCID) were determined based on medical records.

RESULTS

Of 914 patients, frequency of distant metastases was more common in never-smokers than in smokers (59% and 36%, respectively; P<0.001). Although never-smokers were more likely to have LCDD than smokers (18% and 11%, respectively; P=0.038), LCDD were not significantly associated with frequency of distant metastases [49% (LCDD) vs. 42% (non-LCDD); P=0.189] as well as tumor [29% (T3-4) vs. 24% (T1-2); P=0.134] and node [43% (N2-3) vs. 44% (N0-1); P=0.838] stage. Interestingly, never-smokers are more likely to have LCID than smokers (31% and 19%, respectively; P=0.010). In survival analysis, LCID (P=0.001; HR, 0.63) remained a prognostic factor, while LCDD did not.

CONCLUSIONS

This study suggests distinct metastatic pattern and diagnostic processes of never-smokers. The link between survival and incidental detection was also indicated.

Focal Organizing Pneumonia Mimicking Lung Cancer: A Surgeon's View

Focal organizing pneumonia is a unique form of organizing pneumonia. Little is known regarding its clinical and radiological feature, diagnosis, management, and outcome. Twenty patients with focal organizing pneumonia were investigated and compared with 40 patients with bronchogenic carcinoma. There were 38 men (63.3%) and 22 women (36.7%). The mean age was 55 ± 9.9 years. No specific feature in clinical and radiological manifestation was found to distinguish between focal organizing pneumonia and bronchogenic carcinoma. In patients with focal organizing pneumonia, wedge resection was performed in 12 cases and lobectomy in eight cases. Follow-up was complete with a median period of 26 months (range, 6 to 104 months). All patients were free from recurrence of organizing pneumonia. Clinical and radiologic findings of focal organizing pneumonia are nonspecific, and this unique form of organizing pneumonia is difficult to differentiate from lung cancer. Surgical resection allows both diagnosis and cure. However, considering the benign nature of this disease, major pulmonary resections should be avoided.

Isolated pulmonary cryptococcosis in an immunocompetent boy

Pulmonary cryptococcosis is rare in immunocompetent subjects. Here, we present the case of a 16-year-old boy who was referred to our pediatric department for the management of multiple consolidations detected on chest radiography, which was routinely performed when the patient was being evaluated for an ankle fracture. Fine needle aspiration biopsy was performed, and the definitive diagnosis was established as cryptococcal pneumonia. After 8 weeks of antifungal treatment, the pulmonary nodules on the chest radiographs disappeared.

Solitary pulmonary nodule due to Mycobacterium intracellulare: the first case in Korea

Here, we describe a case of a solitary pulmonary nodule due to Mycobacterium intracellulare infection. To the best of our knowledge, this is the first case reported in Korea. A 45-year- old female, exhibiting no respiratory symptoms, was admitted to our hospital due to the appearance of a solitary pulmonary nodule on a chest radiograph. Computed tomography revealed a 2.5 cm nodule with an irregular shape and some marginal spiculation in the right upper lobe. Positron emission tomography with fluorodeoxyglucose imaging revealed positive tumor uptake (maximum standardized uptake value=8.8). Bronchoscopy yielded no specific histological findings and no bacteriological findings. Percutaneous transthoracic lung biopsy revealed epithelioid granuloma but no acid-fast bacilli were detected. The patient received isoniazid, rifampin, ethambutol, and pyrazinamide for the treatment of "tuberculoma". Five weeks after the patient was admitted, numerous mycobacterial colonies were detected on a bronchial washing fluid culture. These colonies were subsequently identified as Mycobacterium intracellulare. A final diagnosis of M. intracellulare pulmonary disease was made, and the patient's treatment regimen was changed to a combination therapy consisting of clarithromycin, rifampin, and ethambutol.

Mycobacterium abscessus pulmonary infection presenting as a solitary pulmonary nodule

Nontuberculous mycobacterial pulmonary infection is a rare cause of a solitary pulmonary nodule. All previously reported cases were caused by Mycobacterium avium complex, and a solitary pulmonary nodule caused by other NTM species has been very rarely reported. We describe the first case of Mycobacterium abscessus infection presenting as a solitary pulmonary nodule in a 51-year-old asymptomatic adult patient.

Solitary pulmonary nodules: dynamic enhanced multi-detector row CT study and comparison with vascular endothelial growth factor and microvessel density

PURPOSE

To evaluate enhancement dynamics of solitary pulmonary nodules at multi-detector row computed tomography (CT) and to correlate results with extent of tumor angiogenesis in pathologic specimens.

MATERIALS AND METHODS

One hundred thirty-one patients with solitary pulmonary nodules underwent unenhanced thin-section CT, followed by dynamic helical CT (throughout the nodule for 30 mm along the z-axis [13 images] and at 20-second intervals for 3 minutes [130 images total]) after intravenous injection of 120 mL of contrast medium. Diagnosis of malignancy or benignancy was assigned in 109 patients, and follow-up imaging suggested benignancy in the remaining 22. CT findings were analyzed for peak attenuation, net enhancement, and enhancement dynamics. In 54 patients with surgical diagnoses, Pearson correlation coefficient was used to correlate enhancement pattern with extent of microvessel density and vascular endothelial growth factor (VEGF) staining.

RESULTS

With 30 HU or more of net enhancement as a cutoff value in differentiation of malignant and benign nodules, sensitivity for malignant nodules was 99% (69 of 70 malignant nodules), specificity was 54% (33 of 61 benign nodules), positive predictive value was 71% (69 of 97 malignant readings), negative predictive value was 97% (33 of 34 benign readings), and accuracy was 78% (102 of 131 nodules). Peak attenuation was correlated positively with extent of microvessel density (r = 0.369, P =.006) and VEGF staining (r = 0.277, P =.042). Malignant nodules showed significantly higher VEGF expression (P =.009) than that of benign nodules.

CONCLUSION

Dynamic enhancement with multi-detector row CT shows high sensitivity and negative predictive values for diagnosis of malignant nodules but low specificity because of highly enhancing benign nodules. Extent of enhancement reflects underlying nodule angiogenesis.