The solitary pulmonary nodule

Leveraging Deep Learning Decision-Support System in Specialized Oncology Center: A Multi-Reader Retrospective Study on Detection of Pulmonary Lesions in Chest X-ray Images

Chest X-ray (CXR) is considered to be the most widely used modality for detecting and monitoring various thoracic findings, including lung carcinoma and other pulmonary lesions. However, X-ray imaging shows particular limitations when detecting primary and secondary tumors and is prone to reading errors due to limited resolution and disagreement between radiologists. To address these issues, we developed a deep-learning-based automatic detection algorithm (DLAD) to automatically detect and localize suspicious lesions on CXRs. Five radiologists were invited to retrospectively evaluate 300 CXR images from a specialized oncology center, and the performance of individual radiologists was subsequently compared with that of DLAD. The proposed DLAD achieved significantly higher sensitivity (0.910 (0.854–0.966)) than that of all assessed radiologists (RAD 10.290 (0.201–0.379), p < 0.001, RAD 20.450 (0.352–0.548), p < 0.001, RAD 30.670 (0.578–0.762), p < 0.001, RAD 40.810 (0.733–0.887), p = 0.025, RAD 50.700 (0.610–0.790), p < 0.001). The DLAD specificity (0.775 (0.717–0.833)) was significantly lower than for all assessed radiologists (RAD 11.000 (0.984–1.000), p < 0.001, RAD 20.970 (0.946–1.000), p < 0.001, RAD 30.980 (0.961–1.000), p < 0.001, RAD 40.975 (0.953–0.997), p < 0.001, RAD 50.995 (0.985–1.000), p < 0.001). The study results demonstrate that the proposed DLAD could be utilized as a decision-support system to reduce radiologists’ false negative rate.

How preserved regional pulmonary function after thoracoscopic segmentectomy in clinical stage I non-small cell lung cancers in right upper lobe

OBJECTIVE

To investigate the efficacy of regional respiratory preservation after pulmonary resection for clinical stage I non-small cell lung cancer (NSCLC) in right upper lobe.

METHODS

This retrospective study analysed patients with clinical stage I NSCLC who underwent open thoracotomy lobectomy (OTL, n = 45), thoracoscopic lobectomy (TSL, n = 137), and thoracoscopic segmentectomy (TSS, n = 37) in right upper lobe. The forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were examined at 3 and 6-12 months after the operation. The pre- and post-operative lung volumes were evaluated by three-dimensional reconstructed computed tomography. The rates of post- and pre-operative FVC, FEV1, and lung volumes were compared amongst the three groups.

RESULTS

Significant differences were found in both FVC and FEV1 at 6-12 months between TSL and OTL (p < 0.01 and p = 0.02, respectively). The respiratory recovery rates of FVC and FEV1 at 6-12 months were significantly higher in TSS (98.6% ± 1.52% and 96.5% ± 1.66%) than in TSL (93.4% ± 0.79% and 90.4% ± 0.86%) (FVC: p < 0.01 and FEV1: p < 0.01). The volumetric changes were greater in TSL than in TSS for the right middle lobe (19.6% ± 2.39% and 9.59% ± 4.66%; p = 0.06) and right lower lobe (48.3% ± 2.84% and 27.9% ± 5.47%; p < 0.01) CONCLUSION: TSS might be superior to TSL or OTL depending on the moderate expansion of the remaining right lobes.

[Multiple insufficiency fractures (metatarsial, calcaneal and sacral) as the first manifestation of lung adenocarcinoma. A case report and literature review]

Insufficiency fractures, or pathological fractures, are produced after minimal trauma or no prior trauma and normally affect weakened bone. Their presence should be suspected in fractures showing abnormal patterns, when several fractures occur in a short period of time and in those with no apparent or only minimal trauma. On confirmation of an insufficiency fracture, a differential diagnosis should be made between tumoral and metastatic fractures if there is a history of underlying primary malignancy. The epidemiology of lung cancer has changed due to women's adoption of smoking. In women, the most frequent type of lung cancer is adenocarcinoma, which is less aggressive and has lower mortality, with 5-year survival of 9.5%. Consequently, in Spain, 44% of pulmonary nodules are due to adenocarcinomas. Therefore, all solitary pulmonary nodules should be followed-up for at least 5 years. A history of solitary pulmonary nodule is found in one out of every 1,000 x-rays. However, in patients younger than 35 years, only 1% is malignant. In persons with a history of malignancy and age older than 35 years, this percentage increases to 68%. Size larger than 3cm increases the percentage of malignancy to up to 93%. Therefore, in female smokers older than 50 years with a history of solitary pulmonary nodule, the nodule should be considered malignant until demonstrated otherwise. We report for the first time in Spain the case of a woman with risk factors (smoking, age older than 50 years, with a 3-cm solitary pulmonary nodule that showed no significant growth in 3 years) who had multiple insufficiency fractures in a short period of time. Rehabilitation therapy was unsuccessful and the patient underwent investigation for malignancy. Unfortunately, histopathological study confirmed that the fractures were the initial manifestation of lung adenocarcinoma.

Development and validation of a predictive model for the diagnosis of solid solitary pulmonary nodules using data mining methods

Background

The purpose of this study is to develop a predictive model to accurately predict the malignancy of solid solitary pulmonary nodule (SPN) by data mining methods.

Methods

A training cohort of 388 consecutive patients with solid SPNs was used to develop a predictive model to evaluate the malignancy of solid SPNs. By using SPSS Modeler, we utilized logistic regression (LR), artificial neural network (ANN), k-nearest neighbor (KNN), random forest (RF), and support vector machines (SVM) classifiers to build predictive models. Another cohort of 200 consecutive patients with solid SPNs was used to verify the accuracy of the predictive model. Predictive performance was evaluated using the area under the receiver operating characteristic curve (AUC).

Results

There was no significant difference in patients' characteristics between the training cohort and the validation cohort. The AUCs of LR, ANN, KNN, RF, and SVM models for the validation cohort were 0.874±0.0280 (P=0.605), 0.833±0.0351 (P=0.104), 0.792±0.0418 (P=0.014), 0.775±0.0400 (P=0.013), and 0.890±0.0323 (reference), respectively. The SVM algorithm had the highest AUC, and the best sensitivity (90.3%), specificity (80.4%), positive predictive value (93.9%), negative predictive value (71.2%) and accuracy (88.0%) for the validation cohort among the five models.

Conclusions

Data mining by SVM might be a useful auxiliary algorithm in predicting malignancy of solid SPNs.

MRI in Evaluation of Solitary Pulmonary Nodules

OBJECTIVES

The aim of this study is to assess magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), T2-weighted image (T2WI), and apparent diffusion coefficient (ADC) maps' threshold values before computed tomography (CT)-guided transthorasic biopsy in solitary pulmonary nodules (SPN) by describing tumoral cell density.

MATERIALS AND METHODS

Patients who had SPN were prospectively evaluated with MRI (T1WI, T2WI) and DWI (b=0, b=500, b=1000).The ADC maps were created for each patient. Before the biopsy, lesion muscle ratios (LMR) at T2WI, ADC value, and lesion spinal cord ratio at each b values were noted. The measurements were correlated with the histopathological results.

RESULTS

A total of 53 patients were included in the study: 30.2% (n=16) were female, and 69.8% (n=37) were male. Among them, 17 lesions (32.1%) were benign, and 36 lesions (67.9%) were malignant. The age varied between 40 and 82 years, with a mean of 61.7±9.1 years. The SPN diameters were between 10 and 30 mm, and the median was 24 mm. The LSR0 and LMR values were not statistically significant in detecting malignancy. LSR500 >0.53 value can predict malignancy with 100% sensitivity and 70.6% specificity. LSR1000 >0.53 can predict malignancy with 88.9% sensitivity and 88.2% specificity. Setting the cut-off value at 0.9×10^-3, the ADC values had a sensitivity of 72.2% and a specificity of 88.2% for predicting malignancy.

CONCLUSION

For SPN follow-up, a new following-up protocol can be safely established using DWI and ADC mapping. Using these MRI parameters might decrease unnecessary biopsy rates and complications of biopsies.

Visual assessment of calcification in solitary pulmonary nodules on chest radiography: correlation with volumetric quantification of calcification

PURPOSE

To assess the ability of digital chest radiography (CXR) to reveal calcification in solitary pulmonary nodules (SPNs), and to examine the correlation between a visual assessment and volumetric quantification of the calcification.

MATERIALS AND METHODS

This study was a retrospective review of 220 SPNs identified by both CXR and chest CT. Eleven observers did blind review of the CXR images and scored nodule calcification on a confidence scale of 1 to 5. The area under the receiver operating characteristics (ROC) curve (AUC) was obtained to analyze the diagnostic performance. The intraclass correlation coefficient (ICC) for interrater reliability was calculated. The AUC and ICC were calculated according to the following nodule diameter groups: group 1 (< 10 mm), group 2 (≥ 10 mm and < 20 mm), and group 3 (≥ 20 mm).

RESULTS

Of the 220 SPNs, 145 SPNs (65.6%) were identified as non-calcified and 75 (34.4%) as calcified. The average percentage of calcification volume in SPN > 160 HU (Vol160HU) among the 75 calcified nodules was 47.5%. The mean Vol160HU of the 68 SPNs classified as having definite calcification was 51.1%. The overall AUC was 0.71. The AUCs for groups 1, 2, and 3 was 0.835, 0.639, and 0.620, respectively. The ICCs for groups 1, 2, 3 was 0.65, 0.48, and 0.33, respectively.

CONCLUSION

The overall diagnostic performance of digital CXR to predict calcification in SPNs was moderately accurate and the diagnostic performance for predicting calcification in SPNs was significantly higher, and interobserver reproducibility was good when SPN < 10 mm compared with ≥ 10 mm in diameter.

KEY POINTS

• The misdiagnosis of a non-calcified nodule as a calcified one by CXR could lead to poor management choices for the SPN. • The diagnostic performance of CXR in predicting calcification was best for nodules < 10 mm in diameter. SPNs with calcification of approximately 50% of their volume tend to be considered calcified. • The diagnostic performance of CXR in identifying calcification was low for nodules ≥ 10 mm in diameter; therefore, we should carefully evaluate calcification carefully for nodules ≥ 10 mm.

The value of 18F-FDG-PET/CT in the diagnosis of solitary pulmonary nodules: A meta-analysis

BACKGROUND

Solitary pulmonary nodules (SPNs) are common imaging findings. Many studies have indicated that F-fluorodeoxyglucose positron emission tomography/computed tomography (F-FDG-PET/CT) is an accurate test for distinguishing benign and malignant SPNs. The aim of this study was to investigate the value of F-FDG-PET/CT in the diagnosis of malignant SPNs.

METHODS

We systematically searched the PubMed and Embase databases up to March 2017, and published data on sensitivity, specificity, and other measures of diagnostic accuracy of F-FDG-PET/CT in the diagnosis of malignant SPNs were meta-analyzed. Statistical analyses were undertaken using Meta-DiSc 1.4 software and Stata version 12.0. The measures of accuracy of F-FDG-PET/CT in the diagnosis of malignant SPNs were pooled using random-effects models.

RESULTS

A total of 20 publications reporting 21 studies were identified. Pooled results indicated that F-FDG-PET/CT showed a diagnostic sensitivity of 0.89 (95% confidence interval [CI], 0.87-0.91) and a specificity of 0.70 (95% CI, 0.66-0.73). The positive likelihood ratio was 3.33 (95% CI, 2.35-4.71) and the negative likelihood ratio was 0.18 (95% CI, 0.13-0.25). The diagnostic odds ratio was 22.43 (95% CI, 12.55-40.07).

CONCLUSIONS

F-FDG-PET/CT showed insufficient sensitivity and specificity for diagnosing malignant SPNs; it cannot replace the "gold standard" pathology by resection or percutaneous biopsy. Larger studies are required for further evaluation.

Early Lung Adenocarcinoma in Mice: Micro-Computed Tomography Manifestations and Correlation with Pathology

Lung cancer is the most common fatal malignancy for both men and women and adenocarcinoma is the most common histologic type. Early diagnosis of lung cancer can significantly improve the survival rate of patients. This study aimed to investigate the micro-computed tomography (micro-CT) manifestations of early lung adenocarcinoma (LAC) in mice and to provide a new perspective for early clinical diagnosis. Early LAC models in 10 mice were established by subcutaneously injecting 1-methyl-3-nitro-1-nitrosoguanidine (MNNG) solution. Micro-CT scan and multiple planar reconstruction (MPR) were used for mouse lungs. Micro-CT features of early LAC, especially the relationships between tumor and bronchus, were analyzed and correlated with pathology. Micro-CT findings of early LAC were divided into three types: non-solid (n = 8, 6%), partly solid (n = 85, 64%) and totally solid (n = 39, 30%). Tumor-bronchus relationships, which could be observed in 110 of 132(83%) LAC, were classified into four patterns: type I (n = 16, 15%), bronchus was truncated at the margin of the tumor; type II (n = 33, 30%), bronchus penetrated into the tumor with tapered narrowing and interruption; type III (n = 38, 35%), bronchus penetrated into the tumor with a patent and intact lumen; type IV (n = 99, 90%), bronchus ran at the border of the tumor with an intact or compressed lumen. Micro-CT manifestations of early LAC correlated well with pathological findings. Micro-CT can clearly demonstrate the features of mouse early LAC and bronchus-tumor relationships, and can also provide a new tool and perspective for the study of early LAC.

Combination diagnosis of multi-slice spiral computed tomography and secretary phospholipase A2-IIa for solitary pulmonary nodules

INTRODUCTION

This study was aimed to compare the diagnostic value of multi-slice spiral computed tomography (CT) and secretary phospholipase A2-IIa (sPLA2-IIa) in differentiating between malignant and benign solitary pulmonary nodules (SPNs).

METHODS

A total of 223 patients with SPNs (91 patients with malignant SPNs and 132 patients with benign SPNs) were included from Weihai Central Hospital during October 2014 to December 2016. SPN diagnosis was confirmed in all patients using needle biopsy, surgery and bronchoscopy. The patients were managed with dynamic multi-slice CT scans, and their sPLA2-IIa levels were also detected. By selecting the area of interest of focus, the perfusion parameters of multi-slice CT targeting the focus were obtained.

RESULTS

The levels of MTT, PS, BV, BF and sPLA2-IIa significantly increased with increasing severity of SPNs (P<.05). Notably, BV (area under the ROC curve [AUC]=0.915; 95%CI: 0.88-0.95; sensitivity=91.21%; specificity=78.79%) showed a higher potential to discriminate patients with malignant SPNs from those with benign SPNs than did BF (AUC=0.712; 95%CI: 0.65-0.78; sensitivity=72.50%; specificity=59.10%), PS (AUC=0.772; 95%CI: 0.71-0.84; sensitivity=65.93%; specificity=82.58%) and MTT (AUC=0.600; 95%CI: 0.52-0.68; sensitivity=52.75%; specificity=78.03%). Finally, the combined diagnostic value of BV and sPLA2-IIa was quite ideal (AUC=0.947; 95%CI: 0.92-0.97; sensitivity=85.70%; specificity=92.70%) for malignant and benign SPNs.

CONCLUSIONS

The combined diagnostic value of BV and sPLA2-IIa appeared as a desirable detection method for malignant and benign SPNs.

Changes in pulmonary function in lung cancer patients after video-assisted thoracic surgery

BACKGROUND

Video-assisted thoracoscopic surgery (VATS) is widely performed in patients with resectable non-small cell lung cancer. However, it is unknown whether VATS sublobar resection has advantages compared with VATS lobectomy in preserving pulmonary function.

METHODS

Three hundred patients with non-small cell lung cancer who underwent VATS were enrolled. Pulmonary function tests were performed three times: preoperatively, and at 3 and 12 months postoperatively. Pulmonary function was compared between the VATS lobectomy group (n = 227) and the VATS sublobar resection group (n = 73).

RESULTS

The VATS sublobar resection group had greater preserved pulmonary function than the VATS lobectomy group at 3 and 12 months postoperatively (p < 0.001). However, a VATS lobectomy of the right upper or right middle lobe revealed no difference in forced vital capacity (-1.21% versus -1.45%; p = 0.88) or the diffusion capacity of carbon monoxide (-3.99% versus -2.45%; p = 0.61) compared with VATS sublobar resection after 12 months. In those who underwent VATS of the right lower lobe, forced expiratory volume in 1 second (-8.60% versus -3.69%; p = 0.12) was not different between the two groups after 12 months. Video-assisted thoracoscopic surgery lobectomy of the left upper or left lower lobe resulted in lower pulmonary function than VATS sublobar resection (p < 0.05).

CONCLUSIONS

Patients with non-small cell lung cancer who underwent VATS sublobar resection demonstrated greater pulmonary function than those who underwent VATS lobectomy. However, in right-side VATS lobectomy, some differences dissipated at 1 year.

Early diagnosis of solitary pulmonary nodules

Early detection of solitary pulmonary nodules (SPNs) and early treatment are of great importance. However, patients with early SPNs always do not present with any symptoms or signs, only to demonstrate SPNs in radiology findings. So it is very critical to improve the ability to identify the SPNs, and with the development of sorts of diagnostic modalities, the accuracy in the evaluation of the SPNs has improved greatly. In this paper, the diagnostic methods and techniques of SPNs are reviewed.

An update on the evaluation and management of small pulmonary nodules

The widespread utilization of chest CT scans has increased the importance of the proper evaluation of incidentally found lung nodules. The primary goal in the evaluation of these nodules is to determine whether they are malignant or benign. Clinical factors such as older age, tobacco smoking, and current or remote history of malignancy increase the pretest likelihood of malignancy. Radiological features of these nodules are important in differentiating benign from malignant lesions. However, the etiology of the lung nodules frequently remains indeterminate and requires further evaluation. The approach to the management of indeterminate lung nodules ranges between observation with repeat chest CT scan, further diagnostic studies such as PET scan or invasive procedures to obtain tissue diagnosis. This article reviews the importance of the different radiological features of lung nodules. This is followed by an update on the approach to the management of the different types of small lung nodules.

[Diagnosis and management of solitary pulmonary nodules]

目前，肺癌已跃居成为我国发病率及死亡率最高的恶性肿瘤，总体5年生存率较低；早诊早治是提高肺癌患者生存率及改善预后的关键，而早期肺癌患者常无任何症状和体征，只在影像学上表现为肺孤立性结节病变。提高对孤立性肺结节良恶性的鉴别诊断能力是临床诊治过程中的难点与热点。随着各种诊治技术的发展，孤立性肺结节病变性质的诊断准确率已大大提高。

Positron emission tomography-computed tomography in the management of lung cancer: An update

This communication presents an update on the current role of positron emission tomography-computed tomography (PET-CT) in the various clinical decision-making steps in lung carcinoma. The modality has been reported to be useful in characterizing solitary pulmonary nodules, improving lung cancer staging, especially for the detection of nodal and metastatic site involvement, guiding therapy, monitoring treatment response, and predicting outcome in non-small cell lung carcinoma (NSCLC). Its role has been more extensively evaluated in NSCLC than small cell lung carcinoma (SCLC). Limitations in FDG PET-CT are encountered in cases of tumor histotypes characterized by low glucose uptake (mucinous forms, bronchioalveolar carcinoma, neuroendocrine tumors), in the assessment of brain metastases (high physiologic 18F-FDG uptake in the brain) and in cases presenting with associated inflammation. The future potentials of newer PET tracers beyond FDG are enumerated. An evolving area is PET-guided assessment of targeted therapy (e.g., EGFR and EGFR tyrosine kinase overexpression) in tumors which have significant potential for drug development.

Evaluation of an improved method of simulating lung nodules in chest tomosynthesis

BACKGROUND

Simulated pathology is a valuable complement to clinical images in studies aiming at evaluating an imaging technique. In order for a study using simulated pathology to be valid, it is important that the simulated pathology in a realistic way reflect the characteristics of real pathology.

PURPOSE

To perform a thorough evaluation of a nodule simulation method for chest tomosynthesis, comparing the detection rate and appearance of the artificial nodules with those of real nodules in an observer performance experiment.

MATERIAL AND METHODS

A cohort consisting of 64 patients, 38 patients with a total of 129 identified pulmonary nodules and 26 patients without identified pulmonary nodules, was used in the study. Simulated nodules, matching the real clinically found pulmonary nodules by size, attenuation, and location, were created and randomly inserted into the tomosynthesis section images of the patients. Three thoracic radiologists and one radiology resident reviewed the images in an observer performance study divided into two parts. The first part included nodule detection and the second part included rating of the visual appearance of the nodules. The results were evaluated using a modified receiver-operating characteristic (ROC) analysis.

RESULTS

The sensitivities for real and simulated nodules were comparable, as the area under the modified ROC curve (AUC) was close to 0.5 for all observers (range, 0.43-0.55). Even though the ratings of visual appearance for real and simulated nodules overlapped considerably, the statistical analysis revealed that the observers to were able to separate simulated nodules from real nodules (AUC values range 0.70-0.74).

CONCLUSION

The simulation method can be used to create artificial lung nodules that have similar detectability as real nodules in chest tomosynthesis, although experienced thoracic radiologists may be able to distinguish them from real nodules.

The utility of two somatostatin analog radiopharmaceuticals in assessment of radiologically indeterminate pulmonary lesions

PURPOSE

The aim of our study was to assess diagnostic accuracy of Tc-99m depreotide and Tc-99m-EDDA/HYNIC-TOC scintigraphy for evaluation of pulmonary lesions that appeared ambiguous on computed tomography (CT).

MATERIAL AND METHODS

Forty-nine consecutive patients (37 men and 12 women; mean age, 60 ± 11 years) with 60 pulmonary lesions on chest radiography and CT were referred for nuclear imaging. They were prospectively allocated to undergo whole-body scintigraphy (WBS) and single photon emission computed tomography (SPECT) using either Tc-99m depreotide (26 patients, group 1) or Tc-99m-EDDA/HYNIC-TOC imaging (23 patients, group 2). Histologic findings after tissue biopsy served as a gold standard for determining diagnostic accuracy of the 2 somatostatin analogs. Visual assessment was complemented by semiquantitative analysis based on target to background ratio.

RESULTS

Among the 32 pulmonary lesions scanned with Tc-99m depreotide, focal uptake was increased in 22 of 25 malignancies, whereas no uptake was found in 6 of 7 benign lesions (88% sensitivity, 85% specificity, and 88% accuracy) on both WBS and SPECT. Imaging of 28 pulmonary lesions with Tc-99m-EDDA/HYNIC-TOC had a similar diagnostic yield (sensitivity 87%, specificity 84%, and accuracy 86%). Overall, target to background ratios were higher on SPECT than WBS but not significantly different between groups 1 and 2 (SPECT 2.72 ± 0.70 vs. 2.71 ± 0.50, WBS 1.61 ± 0.32 vs. 1.62 ± 0.28, respectively).

CONCLUSION

This study demonstrates that Tc-99m depreotide and Tc-99m-EDDA/HYNIC-TOC have similar diagnostic value for characterizing pulmonary lesions that appear ambiguous on CT.

High resolution spiral CT for determining the malignant potential of solitary pulmonary nodules: refining and testing the test

BACKGROUND

A solitary pulmonary nodule (SPN) may represent early stage lung cancer. Lung cancer is a devastating disease with an overall 5-year mortality rate of approximately 84% but with early detection and surgery as low as 47%. Currently a contrast-enhanced multiple-row detector CT (MDCT) scan is the first examination when evaluating patients with suspected lung cancer.

PURPOSE

To apply an additional high resolution CT (HRCT) to SPNs to test whether certain morphological characteristics are associated with malignancy, to assess the diagnostic accuracy of HRCT in the characterization of SPNs, and to address the reproducibility of all measures.

MATERIAL AND METHOD

Two hundred and thirteen participants with SPNs were included in a follow-up study. Blinded HRCT images were assessed with regard to margin risk categories (MRCs), calcification patterns and certain other characteristics and overall malignancy potential ratings (MPRs) were given. Morphological characteristics were tested against reference standard and ROC methodology was applied to assess diagnostic accuracy. Reproducibility was measured with Kappa statistics and 95% confidence intervals were computed for all results. Histopathology (90%) and CT follow-up (10%) were used as reference standard.

RESULTS

MRCs (P < 0.001), calcification patterns (P = 0.003), and pleural retraction (P < 0.001) were all statistically significantly associated to malignancy. Reproducibility was moderate to substantial. Sensitivity, specificity, and overall diagnostic accuracy of HRCT were 98%, 23% and 87%, respectively. Reproducibility was substantial.

CONCLUSION

Statistically significant associations between SPN MRCs, calcification patterns, pleural retraction and malignancy were found. HRCT yielded a very high sensitivity and a somewhat lower specificity for malignancy. Reproducibility was high.

Accuracy of early and delayed FDG PET-CT and of contrast-enhanced CT in the evaluation of lung nodules: a preliminary study on 30 patients

PURPOSE

The aim of our prospective study was to compare the diagnostic accuracy of early, delayed and dual-time-point positron emission tomography (PET) acquisition with contrast enhanced computed tomography (CT) within a PET-CT examination in the evaluation of pulmonary solitary nodules (SPNs).

MATERIALS AND METHODS

Thirty patients were enrolled in the study. All the patients underwent a dual-time-point PET-CT examination. Whole-body PET images were acquired at 50 min after fluorine18-fluorodeoxyglucose ((18)F-FDG) administration (early), followed by a chest acquisition (delayed). Lung nodules with maximum standardised uptake value SUVmax > or =2.5 were considered malignant. SUVmax was calculated on early and delayed images; SUV increasing > or =10% (Delta SUVmax) was considered suggestive of malignancy. Absence of significant lung nodule enhancement (<15 Delta HU) at CT was considered strongly predictive of benignity. For the CT morphological assessment, the irregularity of the shape of each lesion was rated. PET-CT results were related to histological assays and clinical records. Diagnostic accuracy was assessed by area under the receiveroperarting characteristic (ROC) curves analysis.

RESULTS

Early and delayed SUVmax of malignant nodules were significantly higher than those of benign disease. Early SUVmax sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 77%, 91%, 79.5% and 66.7%; delayed SUVmax corresponding values were 77%, 66%, 74% and 66%; dual-time-point SUVmax values were 83%, 67%, 75% and 74%; DeltaHU values were 94%, 34%, 67%, 96%; CT morphologic evaluation values were 61%, 46%, 60%, 47%. Area under the curve (AUC) for early SUVmax was 0.79, for delayed SUVmax 0.80, for dual-time-point SUVmax 0.85, for DeltaHU 0.63 and for CT morphologic assessment 0.58.

CONCLUSIONS

In our small series of patients, early and delayed SUVmax showed comparable accuracies, whereas morphological and contrast enhanced CT evaluations showed the lowest accuracies. Dual-time-point SUVmax showed the largest AUC. However, dual-time-point SUVmax was most sensitive, whereas single-time-point SUVmax was most specific.

Does the availability of positron emission tomography modify diagnostic strategies for solitary pulmonary nodules? An observational study in France

Background

Previous studies showed that at the individual level, positron emission tomography (PET) has some benefits for patients and physicians in terms of cancer management and staging. We aimed to describe the benefits of (PET) in the management of solitary pulmonary nodules (SPNs) in a population level, in terms of the number of diagnostic and invasive tests performed, time to diagnosis and factors determining PET utilization.

Methods

In an observational study, we examined reports of computed tomography (CT) performed and mentioning "spherical lesion", "nodule" or synonymous terms. We found 11,515 reports in a before-PET period, 2002–2003, and 20,075 in an after-PET period, 2004–2005. Patients were followed through their physician, who was responsible for diagnostic management.

Results

We had complete data for 112 patients (73.7%) with new cases of SPN in the before-PET period and 250 (81.4%) in the after-PET period. Patients did not differ in mean age (64.9 vs. 64.8 years). The before-PET patients underwent a mean of 4 tests as compared with 3 tests for the after-PET patients (p = 0.08). Patients in the before-PET period had to wait 41.4 days, on average, before receiving a diagnosis as compared with 24.0 days, on average, for patients in the after-PET period who did not undergo PET (p < 0.001). In the after-PET period, 11% of patients underwent PET during the diagnostic process. A spiculated nodule was more likely to determine prescription for PET (p < 0.001). Multivariate analysis revealed that patients in both periods underwent fewer tests when PET was prescribed by general practitioners (p < 0.001) and if the nodule was not spiculated (p < 0.001). The proportion of unnecessary invasive approaches prescribed (47% vs. 49%) did not differ between the groups.

Conclusion

In our study, 1 year after the availability of PET, the technology was not the first choice for diagnostic management of SPN. Even though we observed a tendency for reduced number of tests and mean time to diagnosis with PET, these phenomena did not fully relate to PET availability in health communities. In addition, the availability of PET in the management of SPN diagnosis did not reduce the overall rate of unnecessary invasive approaches.

Solitary pulmonary nodule on helical dynamic CT scans: analysis of the enhancement patterns using a computer-aided diagnosis (CAD) system

Objective

We wanted to investigate the usefulness of a computer-aided diagnosis (CAD) system in assisting radiologists to diagnosis malignant solitary pulmonary nodules (SPNs), as compared with diagnosing SPNs with using direct personal drawing.

Materials and Methods

Forty patients with SPNs were analyzed. After the pre-contrast scan was performed, an additional ten series of post-contrast images were obtained at 20-second intervals. Two investigators measured the attenuation values of the SPNs: a radiologist who drew the regions of interest (ROIs), and a technician who used a CAD system. The Bland and Altman plots were used to compare the net enhancement between a CAD system and direct personal drawing. The diagnostic characteristics of the malignant SPNs were calculated by considering the CAD and direct personal drawing and with using Fisher's exact test.

Results

On the Bland and Altman plot, the net enhancement difference between the CAD system and direct personal drawing was not significant (within ± 2 standard deriation). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of diagnosing malignant SPNs using CAD was 92%, 85%, 75%, 96% and 88%, respectively. The sensitivity, specificity, PPV, NPV and accuracy of diagnosing malignant SPNs using direct drawing was 92%, 89%, 79%, 92% and 88%, respectively.

Conclusion

The CAD system was a useful tool for diagnosing malignant SPNs.

Standardized uptake value-based evaluations of solitary pulmonary nodules using F-18 fluorodeoxyglucose-PET/computed tomography

OBJECTIVE

Combined positron emission tomography and computed tomography (PET/CT) might improve the accuracy of PET tracer quantification by providing the exact tumour contour from coregistered CT images. We compared various semiquantitative approaches for the characterization of solitary pulmonary nodules (SPNs) using F-18 fluorodeoxyglucose PET/CT.

METHODS

The final diagnosis of 49 SPNs (46 patients) was based on histopathology (n=33) or patient follow-up (n=16). The regions of interest (ROIs) were drawn around lesions based on the CT tumour contour and mirrored to the coregistered PET images. Quantification of F-18 fluorodeoxyglucose uptake was accomplished by calculating the standardized uptake value (SUV) using three different methods based on: activity from the maximum-valued pixel within the tumour (SUV-max); the mean ROI activity within the transaxial slice containing the maximum-valued pixel (SUV-mean); and the mean activity over the full tumour volume (SUV-vol). SUVs were corrected for partial volume effects and normalized by body surface area, lean body weight, and blood glucose. Recovery coefficients for partial-volume correction were derived from phantom studies. The ability of various SUVs to differentiate between benign and malignant SPNs was determined by calculating the area under the receiver operating characteristic (ROC) curves.

RESULTS

Twenty-six SPNs were malignant and 23 were benign. The area under the ROC curve was 0.78 for SUV-mean, 0.83 for SUV-max, and 0.78 for SUV-vol. SUV-max and its normalizations yielded the highest area under the ROC curve (0.83-0.85); SUV-mean-partial volume corrected-lean body weight resulted in the lowest area under the ROC curve (0.76). At a specificity of 80%, SUV-max-body surface area provided the highest sensitivity (81%) and accuracy (80%) to detect malignant SPN. Using SUV-max with a cutoff of 2.4 at a specificity of 80% resulted in a sensitivity of 62% (accuracy 71%).

CONCLUSION

Various normalizations applied to SUV-max provided the highest diagnostic accuracy for characterization of SPNs. Quantification methods using the exact tumour contour derived from CT in combined PET/CT imaging (ROI mean activity within a single transaxial slice and mean tumour volume activity) did not result in improved differentiation between benign and malignant SPN. Obtaining SUV-max might be sufficient in the clinical setting.

Anatomic segmentectomy in the treatment of stage I non-small cell lung cancer

BACKGROUND

Segmentectomy for early-stage non-small cell lung cancer (NSCLC) remains controversial and has been previously associated with high local recurrence rates. We compared the outcomes of anatomic segmentectomy with lobectomy for stage I NSCLC and investigated the impact of surgical resection margins on recurrence.

METHODS

From 2002 to 2006, 182 anatomic segmentectomies (114 open, 68 video-assisted thoracic surgery [VATS]), were performed for stage 1A (n = 109) or IB (n = 73) NSCLC. These were compared with 246 lobectomies (1A, 114; 1B, 132). Variables analyzed included hospital course, mortality, and patterns of recurrence and survival.

RESULTS

All segmentectomy surgical margins were free of tumor (average margin, 18.2 mm). Operative time (147 versus 216 minutes; p < 0.0001) and estimated blood loss (185 versus 291 mL; p = 0.0003) were significantly reduced after segmentectomy compared with lobectomy. Thirty-day mortality (1.1% versus 3.3%), total complications, disease-free recurrence, and survival were similar between segmentectomy and lobectomy at a mean follow-up of 18.1 and 28.5 months, respectively. There were 32 recurrences after segmentectomy (17.6%) at a mean of 14.3 months (14 locoregional [7.7%], 18 distant [9.9%]), and 89% of recurrences were seen when tumor margins were 2 cm or less. Margin/tumor diameter ratios exceeding 1 were associated with a significant reduction in recurrence rates compared with ratios of less than 1 (25.0% versus 6.2%; p = 0.0014).

CONCLUSIONS

Anatomic segmentectomy can be performed safely by an open or VATS approach. Segmentectomy outcomes compare favorably with standard lobectomy for stage I NSCLC. Margin/tumor ratios of less than 1 are associated with a higher rate of recurrence. Lobectomy should be considered as primary therapy when such margins are not obtainable with segmentectomy in the good-risk patient.

Detección y caracterización del nódulo pulmonar por tomografía computarizada multicorte

Pulmonary nodules are a common finding in routine chest studies. Although there are no pathognomic clinical or radiological signs that enable the exact nature of a pulmonary nodule to be determined, the clinical context and the appropriate characterization of the pulmonary nodule make it possible to reach the correct diagnosis in most cases. This article discusses the most important aspects involved in the use of multislice computed tomography in the noninvasive detection and characterization of pulmonary nodules.

Comparative evaluation of 99mTc-depreotide and 201Tl chloride single photon emission tomography in the characterization of pulmonary lesions

PURPOSE

To compare (99m)Tc-depreotide and (201)Tl chloride SPET in the characterization of pulmonary lesions.

METHODS

Fifty-seven pulmonary lesions from 33 patients suspected of malignancy in computed tomography, were assessed by (99m)Tc-depreotide and (201)Tl early and delayed SPET imaging. Images were visually assessed and the tumour-to-normal (T/N) lung activity ratio for early (ER) and delayed (DR) scans and the retention index (RI), were calculated in every lesion. A final diagnosis was reached for all lesions, based either on histology or prolonged clinical and radiological follow-up.

RESULTS

Twenty-three lesions were characterized as malignant and 34 benign. In visual analysis, all malignant lesions accumulated both tracers resulting in sensitivity and negative predictive values of 100%. However, false positive interpretations resulted in a specificity of 64.7% and 67.6% for (99m)Tc-depreotide and (201)Tl, respectively. ER and DR of both agents and the RI of (99m)Tc-depreotide were significantly higher in malignant, compared to benign lesions. In defining thresholds of abnormality from ROC analysis, a significant increase in specificity was observed for both tracers in both scan phases (91.2% for all), as compared to visual analysis (P<0.01). There was no significant difference in the diagnostic performance between (99m)Tc-depreotide DR and (201)Tl DR, although the former provided the highest T/N ratio.

CONCLUSION

This study demonstrates that (99m)Tc-depreotide and (201)Tl SPET are equally effective and may be useful in the non-invasive determination of lung malignancy. The specificity of both techniques is significantly improved by quantifying radiopharmaceutical accumulation in pulmonary lesions.

Computer-assisted lung nodule volumetry from multi-detector row CT: Influence of image reconstruction parameters

PURPOSE

To investigate differences in volumetric measurement of pulmonary nodules caused by changing the reconstruction parameters for multi-detector row CT.

MATERIALS AND METHODS

Thirty-nine pulmonary nodules less than 2 cm in diameter were examined by multi-slice CT. All nodules were solid, and located in the peripheral part of the lungs. The resultant 48 parameters images were reconstructed by changing slice thickness (1.25, 2.5, 3.75, or 5 mm), field of view (FOV: 10, 20, or 30 cm), algorithm (high-spatial frequency algorithm or low-spatial frequency algorithm) and reconstruction interval (reconstruction with 50% overlapping of the reconstructed slices or non-overlapping reconstruction). Volumetric measurements were calculated using commercially available software. The differences between nodule volumes were analyzed by the Kruskal-Wallis test and the Wilcoxon Signed-Ranks test.

RESULTS

The diameter of the nodules was 8.7+/-2.7 mm on average, ranging from 4.3 to 16.4mm. Pulmonary nodule volume did not change significantly with changes in slice thickness or FOV (p>0.05), but was significantly larger with the high-spatial frequency algorithm than the low-spatial frequency algorithm (p<0.05), except for one reconstruction parameter. The volumes determined by non-overlapping reconstruction were significantly larger than those of overlapping reconstruction (p<0.05), except for a 1.25 mm thickness with 10 cm FOV with the high-spatial frequency algorithm, and 5mm thickness. The maximum difference in measured volume was 16% on average between the 1.25 mm slice thickness/10 cm FOV/high-spatial frequency algorithm parameters and overlapping reconstruction.

CONCLUSION

Volumetric measurements of pulmonary nodules differ with changes in the reconstruction parameters, with a tendency toward larger volumes in high-spatial frequency algorithm and non-overlapping reconstruction compared to the low-spatial frequency algorithm and overlapping reconstruction.

Location as an important predictor of lymph node involvement for pulmonary adenocarcinoma

BACKGROUND

Increasing data implicate histologic grade and radiographic appearance along with tumor size as key prognostic indicators for pulmonary adenocarcinoma. The impact of tumor location on prognosis has not been examined.

METHODS

The records of 530 consecutive patients with pulmonary adenocarcinoma pathologically staged between June 1979 and July 2002 were reviewed. All patients had a preoperative computed tomographic scan of the chest and underwent surgical staging by mediastinoscopy, lymph node sampling, or lymph node dissection. Patients with bronchioalveolar cell carcinoma were excluded. Peripheral tumors were compared with central tumors with regard to stage and survival. A tumor was considered to be central if visualized within the inner third of the lung field or seen bronchoscopically. Patients with T1 cancers were further analyzed on the basis of tumor size. Survival was determined by the Kaplan-Meier analysis and comparisons were made by the log-rank method.

RESULTS

Central tumors were more advanced and demonstrated a significantly (P < .0001) poorer survival than peripheral tumors (median 18 vs 39 months). Sixty percent of patients with central tumors had stage III or stage IV disease compared with 25% of those with peripheral tumors. Central T1 tumors, however, demonstrated a 50% incidence of lymph node involvement. Although the incidence of lymph node metastases increased incrementally with the size of peripheral T1 tumors, it remained 50% for central T1 tumors irrespective of size.

CONCLUSION

Tumor location for pulmonary adenocarcinoma should be considered when planning therapy. Central tumors have a high incidence of lymph node metastases (regardless of size) and a poorer prognosis.

Intrathoracoscopic localization techniques

BACKGROUND

Several techniques for localizing pulmonary nodules have been described, but the advantages and disadvantages of each method remain unclear. We reviewed ultrasound, endofinger, finger palpation and wait and watch, radioguided, vital dye, fluoroscopic, agar marking, and needle wire methods for localizing pulmonary nodules.

METHODS

Original, peer-reviewed, and full-length articles in English were searched with PubMed and ISI Web of Sciences. Case reports and case series with less than 10 patients were excluded.

RESULTS

All localization techniques showed good reliability, but some carry a high rate of major or minor complications and drawbacks.

CONCLUSION

No ideal localization technique is available; thus, the choice still depends on surgeon's preference and local availability of both specialists and instruments.

Sublobar resection for the subcentimeter pulmonary nodule

Several studies have demonstrated an increased local recurrence rate with sublobar resection (SR) when compared with lobar resection for the treatment of non-small-cell lung cancer (NSCLC). Therefore, lobectomy has remained the gold standard therapy for NSCLC with lesser resection reserved as a compromise operation for high-risk patients. The increased identification of small NSCLC tumors by CT scan is leading many surgeons to question the appropriateness of lobectomy for these tumors. There has been increasing interest by many surgeons to use SR as intentional therapy for patients with small peripheral NSCLC. This article reviews the recent literature and evidence supporting intentional SR for NSCLC. Although lobectomy should continue to be regarded as the procedure of choice for NSCLC, we believe that a subset of patients with favorable characteristics may be appropriately treated with intentional SR as long as good assessment of nodal involvement is made. Future investigation is required to better define when SR is appropriate.

Hamartochondrome pulmonaire : une cause rare de nodule pulmonaire solitaire en pédiatrie

Solitary pulmonary nodules are rare in children. We report an eleven year-old girl evaluated for recurrent respiratory symptoms diagnosed with an intraparenchymal pulmonary hamartochondroma. Spiral computed tomography showed a pulmonary nodule in the middle lobe, 17 mm in diameter, without any specific features. In asymptomatic adult patients, guidelines for the management of solitary pulmonary nodules have been described. The management of solitary pulmonary nodules in pediatric patients is discussed.