Small pulmonary nodules: detection at chest CT and outcome

Complications due to ultrasound transthoracic cutting biopsy of peripheral pulmonary lesions and lesions in the chest wall and mediastinum

INTRODUCTION

Evaluation of patients with peripheral lung lesions and lesions of the chest wall and mediastinum is challenging. The nature of the lesion identified by imaging studies can be determined by histological evaluation of biopsies. An important place in this direction is the ever-increasing popularity among thoracic surgeons of the transthoracic biopsy with a cutting needle under ultrasound control (US-TTCNB).

CT-Based Screening for Pulmonary Metastases in Head and Neck Squamous Cell Cancers: Diagnostic Accuracy and Cost Comparison with PET-CECT

This study's objective was to compare detection rates of radiograph, computed tomography (CT), and positron emission tomography-contrast-enhanced computed tomography (PET-CECT) for pulmonary metastasis/synchronous primary lung tumors in head and neck squamous cell cancer (HNSCC) and its association with clinico-radio-pathological factors. Our retrospective study included 837 HNSCC patients from January 2012 to December 2017. Lung nodules were characterized on CT as benign, indeterminate, and metastatic. The true detection rate and statistical significance of associated risk factors were calculated. Risk factors for metastasis were determined using univariate and multivariate logistic regression models. Seventy-five (8.9%) patients had pulmonary metastasis and 3 (0.3%) had second lung primary. Detection rate of pulmonary metastasis by CT was higher (sensitivity-97.3%, specificity-97.2%) as compared to radiograph (sensitivity 49% and specificity 89%). Correlation was found between pulmonary and extra-pulmonary metastasis and N classification (P = 0.01, P = 0.02) and positive low jugular node (P = 0.001, P = 0.001). Using PET-CECT in place of CT costed an extra outlay of 7,033,805 INR (95,551.85 USD) while detecting distant metastasis in only 4 (0.47%) extra cases. Chest CT is a useful pulmonary metastases screening tool in advanced HNSCC patients with reasonable imaging cost as compared to PET-CT.

Efficacy and Safety of Cone-Beam CT Augmented Electromagnetic Navigation Guided Bronchoscopic Biopsies of Indeterminate Pulmonary Nodules

Bronchoscopic biopsy results for indeterminate pulmonary nodules remain suboptimal. Electromagnetic navigation bronchoscopy (ENB) coupled with cone beam computed tomography (CBCT) for confirmation has the potential to improve diagnostic yield. We present our experience using this multimodal approach to biopsy 17 indeterminate nodules in 14 consecutive patients from April to August 2021. Demographic information, nodule characteristics, and biopsy results were recorded. Procedures were performed in a hybrid operating room equipped with a Siemens Artis Q bi-plane CBCT (Siemens, Munich, Germany). After ENB using the superDimension version 7.1 (Medtronic, Plymouth, MN, USA) to target the lesion, radial endobronchial ultrasound was used as secondary confirmation. Next, transbronchial needle aspiration was performed prior to CBCT to evaluate placement of the biopsy tool in the lesion. The average nodule size was 21.7+/−15 mm with 59% (10/17) < 2 cm in all dimensions and 35% (6/17) showing a radiographic bronchus sign. The diagnostic yield of CBCT-guided ENB was 76% (13/17). No immediate periprocedural or postprocedural complications were identified. Our experience with CBCT-guided ENB further supports the comparable efficacy and safety of this procedure compared to other mature biopsy modalities. Studies designed to optimize the lung nodule biopsy process and to determine the contributions from different procedural aspects are warranted.

Lung Nodules Missed in Initial Staging of Breast Cancer Patients in PET/MRI-Clinically Relevant?

Simple Summary

Image-based primary staging in women with newly-diagnosed breast cancer is important to exclude distant metastases, which affect up to 10% of women. The increasing implementation of [¹⁸F]FDG-PET/MRI as a radiation-saving primary staging tool bears the risk of missing lung nodules. Thus, chest CT serves as the diagnostic of choice for the detection and classification of pulmonary nodules. The aim of this study was the evaluation of the clinical relevance of missed lung nodules at initial staging of breast cancer patients in [¹⁸F]FDG-PET/MRI compared with CT. We demonstrated in an homogeneous population of 152 patients that all patients with newly-diagnosed breast cancer and clinically-relevant lung nodules were detected at initial [¹⁸F]FDG-PET/MRI staging. However, due to the lower sensitivity of MRI in detecting lung nodules, a small proportion of clinically-relevant lung nodules were missed. Thus, a supplemental low-dose chest CT after neoadjuvant therapy should be considered for backup.

Abstract

Purpose: The evaluation of the clinical relevance of missed lung nodules at initial staging of breast cancer patients in [¹⁸F]FDG-PET/MRI compared with CT. Methods: A total of 152 patients underwent an initial whole-body [¹⁸F]FDG-PET/MRI and a thoracoabdominal CT for staging. Presence, size, shape and location for each lung nodule in [¹⁸F]FDG-PET/MRI was noted. The reference standard was established by taking initial CT and follow-up imaging into account (a two-step approach) to identify clinically-relevant lung nodules. Patient-based and lesion-based data analysis was performed. Results: No patient with clinically-relevant lung nodules was missed on a patient-based analysis with MRI VIBE, while 1/84 females was missed with MRI HASTE (1%). Lesion-based analysis revealed 4/96 (4%, VIBE) and 8/138 (6%, HASTE) missed clinically-relevant lung nodules. The average size of missed lung nodules was 3.2 mm ± 1.2 mm (VIBE) and 3.6 mm ± 1.4 mm (HASTE) and the predominant location was in the left lower quadrant and close to the hilum. Conclusion: All patients with newly-diagnosed breast cancer and clinically-relevant lung nodules were detected at initial [¹⁸F]FDG-PET/MRI staging. However, due to the lower sensitivity in detecting lung nodules, a small proportion of clinically-relevant lung nodules were missed. Thus, supplemental low-dose chest CT after neoadjuvant therapy should be considered for backup.

Incidental Pulmonary Nodules Found on Shoulder Arthroplasty Preoperative CT Scans

With current emphasis on preoperative templating of anatomical and reverse shoulder arthroplasty (aTSA and rTSA, respectively), patients often receive thin slice (<1.0 mm) computerized tomography (CT) scans of the operative shoulder, which includes about two-thirds of the ipsilateral lung. The purpose of this study is to evaluate the prevalence and management of incidentally detected pulmonary nodules on preoperative CT scans for shoulder arthroplasty. In this single-center retrospective study, we queried records of aTSA and rTSA patients from 2015 to 2020 who received preoperative CT imaging of the shoulder. Compared to patients with negative CT findings, there were significantly more females (63.8% vs. 46.4%; P = .011), COPD (13.0% vs. 4.7%; P = .015), and asthma (18.8% vs. 6.9%; P = .003) among the patients with incidental nodules on CT. Binary logistic regression confirmed that female sex (odds ratio = 2.00; 95% CI = 1.04 to 3.88; P = .037), COPD history (OR = 3.02; 95% CI = 1.05 to 8.65; P = .040), and asthma history (OR = 3.17; 95% CI = 1.30 to 7.77; P = .011) were significantly associated with an incidental nodule finding. Incidental pulmonary nodules found on shoulder arthroplasty preoperative CT scans are often low risk in size with low risk of malignancy, and do not require further workup. This study may provide guidance to orthopedic surgeons on how to manage patients with incidental pulmonary nodules to increase chances of early cancer detection, avoid unnecessary referrals, reduce potentially harmful radiation exposure of serial CT scans, and improve cost efficiency.

Contribution of positron emission tomography/magnetic resonance imaging in musculoskeletal malignancies

Positron emission tomography/computed tomography (PET/CT) is a promising hybrid imaging technique for evaluating musculoskeletal malignancies. Both technologies, independently are useful for evaluating this type of tumors. PET/MR has great potential combining metabolic and functional imaging PET with soft tissue contrast and multiparametric sequences of MR. In this paper we review the existing literature and discuss the different protocols, new available radiotracers to conclude with the scarce evidence available the most useful/probable indications of the PET MR for the for musculoskeletal malignancies.

Free-breathing 3D Stack of Stars GRE (StarVIBE) sequence for detecting pulmonary nodules in 18F-FDG PET/MRI

BACKGROUND

The free-breathing T1-weighted 3D Stack of Stars GRE (StarVIBE) MR sequence potentially reduces artifacts in chest MRI. The purpose of this study was to evaluate StarVIBE for the detection of pulmonary nodules in ¹⁸F-FDG PET/MRI.

MATERIAL AND METHODS

In this retrospective analysis, conducted on a prospective clinical trial cohort, 88 consecutive women with newly diagnosed breast cancer underwent both contrast-enhanced whole-body ¹⁸F-FDG PET/MRI and computed tomography (CT). Patients' chests were examined on CT as well as on StarVIBE and conventional T1-weighted VIBE and T2-weighted HASTE MR sequences, with CT serving as the reference standard. Presence, size, and location of all detectable lung nodules were assessed. Wilcoxon test was applied to compare nodule features and Pearson's, and Spearman's correlation coefficients were calculated.

RESULTS

Out of 65 lung nodules detected in 36 patients with CT (3.7 ± 1.4 mm), StarVIBE was able to detect 31 (47.7%), VIBE 26 (40%) and HASTE 11 (16.8%), respectively. Overall, CT showed a significantly higher detectability than all MRI sequences combined (65 vs. 36, difference 44.6%, p < 0.001). The VIBE showed a significantly better detection rate than the HASTE (23.1%, p = 0.001). Detection rates between StarVIBE and VIBE did not significantly differ (7.7%, p = 0.27), but the StarVIBE showed a significant advantage detecting centrally located pulmonary nodules (66.7% vs. 16.7%, p = 0.031). There was a strong correlation in nodule size between CT and MRI sequences (HASTE: ρ = 0.80, p = 0.003; VIBE: ρ = 0.77, p < 0.001; StarVIBE: ρ = 0.78, p < 0.001). Mean image quality was rated as good to excellent for CT and MRI sequences.

CONCLUSION

The overall lung nodule detection rate of StarVIBE was slightly, but not significantly, higher than conventional T1w VIBE and significantly higher than T2w HASTE. Detectability of centrally located nodules is better with StarVIBE than with VIBE. Nevertheless, all MRI analyses demonstrated considerably lower detection rates for small lung nodules, when compared to CT.

Diagnostic efficiency of whole-body 18F-FDG PET/MRI, MRI alone, and SUV and ADC values in staging of primary uterine cervical cancer

Background

The use of PET/MRI for gynecological cancers is emerging. The purpose of this study was to assess the additional diagnostic value of PET over MRI alone in local and whole-body staging of cervical cancer, and to evaluate the benefit of standardized uptake value (SUV) and apparent diffusion coefficient (ADC) in staging.

Methods

Patients with histopathologically-proven cervical cancer and whole-body ¹⁸F-FDG PET/MRI obtained before definitive treatment were retrospectively registered. Local tumor spread, nodal involvement, and distant metastases were evaluated using PET/MRI or MRI dataset alone. Histopathology or clinical consensus with follow-up imaging were used as reference standard. Tumor SUVmax and ADC were measured and SUVmax/ADC ratio calculated. Area under the curve (AUC) was determined to predict diagnostic performance and Mann-Whitney U test was applied for group comparisons.

Results

In total, 33 patients who underwent surgery (n = 23) or first-line chemoradiation (n = 10) were included. PET/MRI resulted in higher AUC compared with MRI alone in detecting parametrial (0.89 versus 0.73), vaginal (0.85 versus 0.74), and deep cervical stromal invasion (0.96 versus 0.74), respectively. PET/MRI had higher diagnostic confidence than MRI in identifying patients with radical cone biopsy and no residual at hysterectomy (sensitivity 89% versus 44%). PET/MRI and MRI showed equal AUC for pelvic nodal staging (both 0.73), whereas AUC for distant metastases was higher using PET/MRI (0.80 versus 0.67). Tumor SUVmax/ADC ratio, but not SUVmax or ADC alone, was significantly higher in the presence of metastatic pelvic lymph nodes (P < 0.05).

Conclusions

PET/MRI shows higher accuracy than MRI alone for determining local tumor spread and distant metastasis emphasizing the added value of PET over MRI alone in staging of cervical cancer. Tumor SUVmax/ADC ratio may predict pelvic nodal involvement.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40644-020-00372-5.

Typical CT Features of Intrapulmonary Lymph Nodes: A Review

Several studies investigated the appearance of intrapulmonary lymph nodes (IPLNs) at CT with pathologic correlation. IPLNs are benign lesions and do not require follow-up after initial detection. There are indications that IPLNs represent a considerable portion of incidentally found pulmonary nodules seen at high-resolution CT. The reliable and accurate identification of IPLNs as benign nodules may substantially reduce the number of unnecessary follow-up CT examinations. Typical CT features of IPLNs are a noncalcified solid nodule with sharp margins; a round, oval, or polygonal shape; distanced 15 mm or less from the pleura; and most being located below the level of the carina. The term perifissural nodule (PFN) was coined based on some of these characteristics. Standardization of those CT criteria are a prerequisite for accurate nodule classification. However, four different definitions of PFNs can currently be found in the literature. Furthermore, there is considerable variation in the reported interobserver agreement, malignancy rate, and prevalence of PFNs. The purpose of this review was to provide an overview of what is known about PFNs. In addition, knowledge gaps in defining PFNs will be discussed. A decision tree to guide clinicians in classifying nodules as PFNs is provided. Supplemental material is available for this article. © RSNA, 2020 See also the commentary by White and Rubin in this issue.

Hybrid PET/MRI in non-small cell lung cancer (NSCLC) and lung nodules-a literature review

BACKGROUND

The use of hybrid PET/MRI for clinical staging is growing in several cancer forms and, consequently, PET/MRI has also gained interest in the assessment of non-small cell lung cancer (NSCLC) and lung lesions. However, lung evaluation with PET/MRI is associated with challenges related to technical issues and diagnostic image quality. We, therefore, investigated the published literature on PET/MRI for clinical staging in NSCLC or lung nodule detection specifically addressing diagnostic accuracy and technical issues.

METHODS

The data originates from a systematic search performed in PubMed/MEDLINE, Embase, and Cochrane Library on hybrid PET/MRI in patients with cancer for a scoping review published earlier ( https://doi.org/10.1007/s00259-019-04402-8 ). Studies in English and German evaluating the diagnostic performance of hybrid PET/MRI for NSCLC or lung nodule detection in cancer patients were selected. Data reported in peer-reviewed journals without restrictions to year of publication were included.

RESULTS

A total of 3138 publications were identified from which 116 published 2012-2018 were included. Of these, nine studies addressed PET/MRI in NSCLC (4) or lung nodule detection (5). Overall, PET/MRI did not provide advantages in preoperative T- and N-staging in NSCLC compared to PET/CT. The data on M-staging were too few for conclusions to be drawn. The lung nodule detection rate of PET/MRI was comparable to that of PET/CT for FDG-avid nodules larger than 10 mm, but the sensitivity of PET/MRI for detection of non-FDG-avid nodules smaller than 5 mm was low.

CONCLUSION

PET/MRI did not provide advantages in T- and N-staging of NSCLC compared to PET/CT. PET/MRI had a comparable sensitivity for detection of FDG-avid lung nodules and nodules over 10 mm, but PET/CT yielded a higher detection rate in non FDG-avid lung nodules under 5 mm. With PET/MRI, the overall detection rate for lung nodules in various cancer types remains inferior to that of PET/CT due to the lower diagnostic performance of MRI than CT in the lungs.

Statistical modeling can determine what factors are predictive of appropriate follow-up in patients presenting with incidental pulmonary nodules on CT

PURPOSE

To assess the performance of statistical modeling in predicting follow-up adherence of incidentally detected pulmonary nodules (IPN) on CT, based on patient variables (PV), radiology report related variables (RRRV) and physician-patient communication variables (PPCV).

METHODS

200 patients with IPN on CT were retrospectively identified and randomly selected. PV (age, gender, smoking status, ethnicity), RRRV (nodule size, patient context, whether follow-up recommendations were provided) and PPCV (whether referring physician documented IPN and ordered follow-up on the electronic medical record) were recorded. Primary outcome was whether patients received appropriate follow-up within +/- 1 month of the recommended time frame. Statistical methods included logistic regression and machine learning (K-nearest neighbors and support vector machine).

RESULTS

Adherence was low, with or without recommendations provided in the radiology report (23.4 %-27.4 %). Whether the referring physician ordered follow-up was the dominant predictor of adherence in all models. The following variables were statistically significant predictors of whether referring physician ordered follow-up: recommendations provided in the radiology report, smoking status, patient context and nodule size (FDR logworth of respectively 21.18, 11.66, 2.35, 1.63, p < 0.05). Prediction accuracy varied from 72 % (PV) to 93 % (PPCV, all variables).

CONCLUSION

PPCV are the most important predictors of adherence. Amongst all variables, patient context, smoking status, nodule size, and whether the radiologist provided follow-up recommendations in the report were all statistically significant predictors of patient follow-up adherence, supporting the utility of statistical modeling for analytics, quality assurance and optimization of outcomes related to IPN.

Identification of Nonaggressive Pulmonary Nodules Using an Optimized Scoring System

Supplemental Digital Content is available in the text.

Purpose:

The purpose of this study was to define the optimal scoring method for identifying benign intrapulmonary lymph nodes.

Materials and Methods:

Subjects for this study were selected from the COPDGene study, a large multicenter longitudinal observational cohort study. A retrospective case-control analysis was performed using identified nodules on a subset of 377 patients who demonstrated 765 pulmonary nodules on their baseline computed tomography (CT) study. Nodule characteristics of 636 benign nodules (which resolved or showed <20% growth rate at 5 y follow-up) were compared with 51 nodules that occurred in the same lobe as a reported malignancy. Two radiologists scored each pulmonary nodule on the basis of intrapulmonary lymph node characteristics. A simple scoring strategy weighing all characteristics equally was compared with an optimized scoring strategy that weighed characteristics on the basis of their relative importance in identifying benign pulmonary nodules.

Results:

A total of 479 of 636 benign pulmonary nodules had the majority of lymph node characteristics, whereas only 1 subpleural nodule with the majority of lymph node characteristics appeared to be malignant. Only 279 of 479 (58%) of benign pulmonary nodules with the majority of lymph node characteristics were intrafissural or subpleural. The optimized scoring strategy showed improved performance compared with the simple scoring strategy with average area under the curve of 0.80 versus 0.55. Optimized cutoff scores showed negative likelihood values for both readers of <0.2. A simulation showed a potential reduction in CT utilization of up to 36% for Fleischner criteria and up to 5% for LUNG-RADS.

Conclusions:

Nodules with the majority of lymph node characteristics, regardless of location, are likely benign, and weighing certain lymph node characteristics greater than others can improve overall performance. Given the potential to reduce CT utilization, lymph node characteristics should be considered when recommending appropriate follow-up.

Transthoracic ultrasound-guided biopsy in the hands of chest physicians - a stepwise approach

Background: The evaluation of patients with lung lesions is challenging. The nature of the lesion can be determined by pathological evaluation of biopsies. The pulmonologists will be met by increasing demands with regard to biopsy techniques including ultrasound-guided transthoracic needle biopsy (US-TTNB).Objective: The aim of this paper is to present the pulmonologist to a systematic step-by-step guide for performing US-TTNB and to assess the evidence for this approach. Method/results: Indications, contraindications and a step-by-step guide for the techniques used when performing US-TTNB are presented, and major complications and handling of these are described. Conclusion: US-TTNB performed by pulmonologists is a safe and feasible procedure.

Prognostic indicators of pulmonary metastasis in patients with renal cell carcinoma who have undergone radical nephrectomy

The aim of the present study was to validate prognostic indicators of pulmonary metastasis in patients with renal cell carcinoma (RCC) that have undergone nephrectomy treatment. The data from 356 patients who underwent nephrectomy were investigated and subsequently divided into 2 groups, according to the pulmonary metastasis status. The risk factors for pulmonary metastasis were examined in all patients. In the subgroup analysis, the risk factors were additionally verified in patients with pulmonary nodules using univariate and multivariate logistic regression analyses. The status of pulmonary nodules and pulmonary metastasis were confirmed through preoperative chest radiography by two radiologists. Pulmonary metastasis was observed in 33 (9.3%) patients with a median follow-up time of 54.4 months (interquartile range, 38.8-71.8). Patients with pulmonary nodules indicated significantly increased rates of pulmonary metastasis, compared with patients without pulmonary nodules (24.2 vs. 6.1%; P<0.001). In multivariate analysis, the presence of pulmonary nodules [hazard ratio (HR)=3.15; P=0.0262], albumin (HR=0.42; P=0.0490) and pTstage (HR=3.63; P=0.0475) were indicated to be independent prognostic markers for pulmonary metastasis. In subgroup analysis, pTstage was the only independent prognostic indicator for pulmonary metastasis in these patients (HR=9.81; P=0.0033). In patients with RCC, the presence of pulmonary nodules was associated with pulmonary metastasis. Furthermore, pTstage is a negative prognostic indicator in patients with pulmonary nodules. Therefore, a chest radiologic short-term follow-up is required for these patients.

Improved Detection of Small Pulmonary Nodules Through Simultaneous MR/PET Imaging

Magnetic resonance (MR)/PET scanners provide an imaging platform that enables simultaneous acquisition of MR and PET data in perfect spatial and temporal registration. This feature allows improving image quality for the MR and PET images obtained during the course of an examination. In this work the authors demonstrate the use of prospective MR-based motion tracking information for removing motion blur in MR/PET images of small pulmonary nodules. The theoretical basis for the algorithms is presented alongside clinical examples of its use.

Multiple pulmonary nodules in malignancy

PURPOSE OF REVIEW

Multiple pulmonary nodules are a common finding especially with the implementation of lung cancer screening. Available guidelines address the management of solitary pulmonary nodules. The management of the multiple pulmonary nodules would differ based on the characteristic of the nodules, their distribution, and the history of the patients as well.

RECENT FINDINGS

Most of the recent publications on multiple pulmonary nodules consist of individual case reports or case series. Robust population studies are lacking.

SUMMARY

In this article, we propose an approach for management of multiple pulmonary nodules which needs to be validated.

Role of 18F-FDG PET/CT vs CT-scan in patients with pulmonary metastases previously operated on for colorectal liver metastases

OBJECTIVE

There is currently no conclusive scientific evidence available regarding the role of the ¹⁸F-FDG PET/CT for detecting pulmonary metastases from colorectal cancer (PMCRC) in patients operated on for colorectal liver metastases (CRLM). In the follow up of patients who underwent surgery for CRLM, we compare CT-scan and ¹⁸F-FDG PET/CT in patients with PMCRC.

METHODS

We designed the study prospectively performing an ¹⁸F-FDG PET/CT on all patients operated on for CRLM where the CT-scan detected PMCRC during the follow up. We included patients who were operated on for PMCRC because the histological findings were taken as a control rather than biopsies.

RESULTS

Of the 101 pulmonary nodules removed from 57 patients, the CT-scan identified a greater number (89 nodules) than the ¹⁸F-FDG PET/CT (75 nodules) (p < 0.001). Sensitivity was greater with the CT-scan (90 vs 76%, respectively) with a lower specificity (50 vs 75%, respectively) than with the ¹⁸F-FDG PET/CT. There were no differences between positive-predictive value and negative-predictive value. The ¹⁸F-FDG PET/CT detected more pulmonary nodules in four patients (one PMCRC in each of these patients) and more extrapulmonary disease in six patients (four mediastinal lymph nodes, one retroperitoneal lymph node and one liver metastases) that the CT-scan had not detected.

CONCLUSION

Although CT-scans have a greater capacity to detect PMCRC, the ¹⁸F-FDG PET/CT could be useful in the detection of more pulmonary and extrapulmonary disease not identified by the CT-scan. Advances in knowledge: We tried to clarify the utility of ¹⁸F-FDG PET/CT in the management of this subpopulation of patients.

Radiologic Features of Small Pulmonary Nodules and Lung Cancer Risk in the National Lung Screening Trial: A Nested Case-Control Study

Purpose To extract radiologic features from small pulmonary nodules (SPNs) that did not meet the original criteria for a positive screening test and identify features associated with lung cancer risk by using data and images from the National Lung Screening Trial (NLST). Materials and Methods Radiologic features in SPNs in baseline low-dose computed tomography (CT) screening studies that did not meet NLST criteria to be considered a positive screening examination were extracted. SPNs were identified for 73 incident case patients who were given a diagnosis of lung cancer at either the first or second follow-up screening study and for 157 control subjects who had undergone three consecutive negative screening studies. Multivariable logistic regression was used to assess the association between radiologic features and lung cancer risk. All statistical tests were two sided. Results Nine features were significantly different between case patients and control subjects. Backward elimination followed by bootstrap resampling identified a reduced model of highly informative radiologic features with an area under the receiver operating characteristic curve of 0.932 (95% confidence interval [CI]: 0.88, 0.96), a specificity of 92.38% (95% CI: 52.22%, 84.91%), and a sensitivity of 76.55% (95% CI: 87.50%, 95.35%) that included total emphysema score (odds ratio [OR] = 1.71; 95% CI: 1.39, 2.01), attachment to vessel (OR = 2.41; 95% CI: 0.99, 5.81), nodule location (OR = 3.25; 95% CI: 1.09, 8.55), border definition (OR = 7.56; 95% CI: 1.89, 30.8), and concavity (OR = 2.58; 95% CI: 0.89, 5.64). Conclusion A set of clinically relevant radiologic features were identified that that can be easily scored in the clinical setting and may be of use to determine lung cancer risk among participants with SPNs. ^© RSNA, 2017 Online supplemental material is available for this article.

Computer tomography guided lung biopsy using interactive breath-hold control: a randomized study

BACKGROUND

Interactive breath-hold control (IBC) may improve the accuracy and decrease the complication rate of computed tomography (CT)-guided lung biopsy, but this presumption has not been proven in a randomized study.

METHODS

Patients admitted for CT-guided lung biopsy were randomized to biopsy either with (N=201) or without (N=206) IBC. Biopsy accuracy, procedure time, radiation, and complications were compared in the two groups. Predictors for pneumothorax were analyzed.

RESULTS

Procedures performed with the use of IBC (N=130) did not show higher biopsy accuracy (P=0.979) but were associated with a higher risk of pneumothorax (P=0.022) compared to procedures without the use of IBC (N=171). Overall, 50% of the biopsies were malignant, 13% were benign, and 33% were inconclusive (4% missing). Long needle time (P=0.037) and small nodule size (P=0.001) were predictors of pneumothorax.

CONCLUSIONS

The use of IBC for CT-guided lung biopsy was not an advantage for unselected patients in our care, since it did not improve the biopsy accuracy and the risk of pneumothorax was increased.

Paraneoplastic endocrine syndromes

The majority of neoplasms are responsible for symptoms caused by mass effects to surrounding tissues and/or through the development of metastases. However, occasionally neoplasms, with or without endocrine differentiation, acquire the ability to secrete a variety of bioactive substances or induce immune cross-reactivity with the normal tissues that can lead to the development of characteristic clinical syndromes. These syndromes are named endocrine paraneoplastic syndromes when the specific secretory components (hormones, peptides or cytokines) are unrelated to the anticipated tissue or organ of origin. Endocrine paraneoplastic syndromes can complicate the patient's clinical course, response to treatment, impact prognosis and even be confused as metastatic spread. These syndromes can precede, occur concomitantly or present at a later stage of tumour development, and along with the secreted substances constitute the biological 'fingerprint' of the tumour. Their detection can facilitate early diagnosis of the underlying neoplasia, monitor response to treatment and/or detect early recurrences following successful initial management. Although when associated with tumours of low malignant potential they usually do not affect long-term outcome, in cases of highly malignant tumours, endocrine paraneoplastic syndromes are usually associated with poorer survival outcomes. Recent medical advances have not only improved our understanding of paraneoplastic syndrome pathogenesis in general but also enhanced their diagnosis and treatment. Yet, given the rarity of endocrine paraneoplastic syndromes, there is a paucity of prospective clinical trials to guide management. The development of well-designed prospective multicentre trials remains a priority in the field in order to fully characterise these syndromes and provide evidence-based diagnostic and therapeutic protocols.

Improved Detection of Small Pulmonary Nodules Through Simultaneous MR/PET Imaging

Magnetic resonance (MR)/PET scanners provide an imaging platform that enables simultaneous acquisition of MR and PET data in perfect spatial and temporal registration. This feature allows improving image quality for the MR and PET images obtained during the course of an examination. In this work the authors demonstrate the use of prospective MR-based motion tracking information for removing motion blur in MR/PET images of small pulmonary nodules. The theoretical basis for the algorithms is presented alongside clinical examples of its use.

[Diagnostic work-up of pulmonary nodules : Management of pulmonary nodules detected with low‑dose CT screening]

Pulmonary nodules are the most frequent pathological finding in low-dose computed tomography (CT) scanning for early detection of lung cancer. Early stages of lung cancer are often manifested as pulmonary nodules; however, the very commonly occurring small nodules are predominantly benign. These benign nodules are responsible for the high percentage of false positive test results in screening studies. Appropriate diagnostic algorithms are necessary to reduce false positive screening results and to improve the specificity of lung cancer screening. Such algorithms are based on some of the basic principles comprehensively described in this article. Firstly, the diameter of nodules allows a differentiation between large (>8 mm) probably malignant and small (<8 mm) probably benign nodules. Secondly, some morphological features of pulmonary nodules in CT can prove their benign nature. Thirdly, growth of small nodules is the best non-invasive predictor of malignancy and is utilized as a trigger for further diagnostic work-up. Non-invasive testing using positron emission tomography (PET) and contrast enhancement as well as invasive diagnostic tests (e.g. various procedures for cytological and histological diagnostics) are briefly described in this article. Different nodule morphology using CT (e.g. solid and semisolid nodules) is associated with different biological behavior and different algorithms for follow-up are required. Currently, no obligatory algorithm is available in German-speaking countries for the management of pulmonary nodules, which reflects the current state of knowledge. The main features of some international and American recommendations are briefly presented in this article from which conclusions for the daily clinical use are derived.

Comparative Performance of ¹⁸F-FDG PET/MRI and ¹⁸F-FDG PET/CT in Detection and Characterization of Pulmonary Lesions in 121 Oncologic Patients

Our objective was to compare (18)F-FDG PET/MRI (performed using a contrast-enhanced T1-weighted fat-suppressed volume-interpolated breath-hold examination [VIBE]) with (18)F-FDG PET/CT for detecting and characterizing lung lesions in oncologic patients.

METHODS

In 121 oncologic patients with 241 lung lesions, PET/MRI was performed after PET/CT in a single-injection protocol (260 ± 58 MBq of (18)F-FDG). The detection rates were computed for MRI, the PET component of PET/CT, and the PET component of PET/MRI in relation to the CT component of PET/CT. Wilcoxon testing was used to assess differences in lesion contrast (4-point scale) and size between morphologic datasets and differences in image quality (4-point scale), SUVmean, SUVmax, and characterization (benign/malignant) between PET/MRI and PET/CT. Correlation was determined using the Pearson coefficient (r) for SUV and size and the Spearman rank coefficient (ρ) for contrast.

RESULTS

The detection rates for MRI, the PET component of PET/CT, and the PET component of PET/MRI were 66.8%, 42.7%, and 42.3%, respectively. There was a strong correlation in size (r= 0.98) and SUV (r= 0.91) and a moderate correlation in contrast (ρ = 0.48). Image quality was better for PET/CT than for PET/MRI (P< 0.001). Lesion measurements were smaller for MRI than for CT (P< 0.001). SUVmax and SUVmean were significantly higher for PET/MRI than for PET/CT (P< 0.001 each). There was no significant difference in lesion contrast (P= 0.11) or characterization (P= 0.076).

CONCLUSION

In the detection and characterization of lung lesions 10 mm or larger, (18)F-FDG PET/MRI and (18)F-FDG PET/CT perform comparably. Lesion size, SUV and characterization correlate strongly between the two modalities. However, the overall detection rate of PET/MRI remains inferior to that of PET/CT because of the limited ability of MRI to detect lesions smaller than 10 mm. Thus, thoracic staging with PET/MRI bears a risk of missing small lung metastases.

Lung nodule and cancer detection in computed tomography screening

Fundamental to the diagnosis of lung cancer in computed tomography (CT) scans is the detection and interpretation of lung nodules. As the capabilities of CT scanners have advanced, higher levels of spatial resolution reveal tinier lung abnormalities. Not all detected lung nodules should be reported; however, radiologists strive to detect all nodules that might have relevance to cancer diagnosis. Although medium to large lung nodules are detected consistently, interreader agreement and reader sensitivity for lung nodule detection diminish substantially as the nodule size falls below 8 to 10 mm. The difficulty in establishing an absolute reference standard presents a challenge to the reliability of studies performed to evaluate lung nodule detection. In the interest of improving detection performance, investigators are using eye tracking to analyze the effectiveness with which radiologists search CT scans relative to their ability to recognize nodules within their search path in order to determine whether strategies might exist to improve performance across readers. Beyond the viewing of transverse CT reconstructions, image processing techniques such as thin-slab maximum-intensity projections are used to substantially improve reader performance. Finally, the development of computer-aided detection has continued to evolve with the expectation that one day it will serve routinely as a tireless partner to the radiologist to enhance detection performance without significant prolongation of the interpretive process. This review provides an introduction to the current understanding of these varied issues as we enter the era of widespread lung cancer screening.

Correlation of the Strength of Recommendations for Additional Imaging to Adherence Rate and Diagnostic Yield

PURPOSE

The aim of this study was to evaluate the association between the wording of radiologist recommendations for chest CT with the likelihood of recommendation adherence and the diagnostic yield of the recommended follow-up CT imaging.

METHODS

This HIPAA-compliant retrospective study had institutional review board approval, including waiver of the requirement for patient consent. All outpatient chest radiographic (CXR) studies performed at a tertiary care academic medical center in 2008 (n = 29,138) were searched to identify examinations with recommendations for chest CT. The wording of chest CT recommendations was classified as conditional or absolute, on the basis of whether the recommendation stood independent of the clinical judgment of the ordering clinician. Using the radiology information system, patients who underwent chest CT within 90 days of the index CXR study containing the recommendation were determined, and the CT studies were evaluated to determine if there were abnormalities corresponding to the CXR abnormalities that prompted the recommendations. Corresponding abnormalities were categorized as clinically relevant or not, on the basis of whether further workup or treatment was warranted. Groups were compared using t tests and Fisher exact tests.

RESULTS

Recommendations for chest CT appeared in 4.5% of outpatient CXR studies (1,316 of 29,138; 95% confidence interval [CI], 4.3%-4.8%); 39.4% (519 of 1,316; 95% CI, 36.8%-42.0%) were conditional and 60.6% (797 of 1,316; 95% CI, 58.0%-63.2%) were absolute. Patients with absolute recommendations were significantly more likely to undergo follow-up chest CT within 90 days than patients with conditional recommendations (67.8% vs 45.8%, respectively, P < .001). Despite this difference in provider adherence, there was no significant difference between the conditional and absolute recommendation groups with regard to the incidence of clinically relevant corresponding findings (P = .16) or malignancy (P = .08) on follow-up CT.

CONCLUSIONS

Conditional radiologist recommendations are associated with decreased provider adherence, though the likelihood of a clinically relevant finding on follow-up CT is no different than with absolute recommendations.

Diagnostic yield of recommendations for chest CT examination prompted by outpatient chest radiographic findings

PURPOSE

To evaluate the diagnostic yield of recommended chest computed tomography (CT) prompted by abnormalities detected on outpatient chest radiographic images.

MATERIALS AND METHODS

This HIPAA-compliant study had institutional review board approval; informed consent was waived. Reports of all outpatient chest radiographic examinations performed at a large academic center during 2008 (n = 29 138) were queried to identify studies that included a recommendation for a chest CT imaging. The radiology information system was queried for these patients to determine if a chest CT examination was obtained within 1 year of the index radiographic examination that contained the recommendation. For chest CT examinations obtained within 1 year of the index chest radiographic examination and that met inclusion criteria, chest CT images were reviewed to determine if there was an abnormality that corresponded to the chest radiographic finding that prompted the recommendation. All corresponding abnormalities were categorized as clinically relevant or not clinically relevant, based on whether further work-up or treatment was warranted. Groups were compared by using t test and Fisher exact test with a Bonferroni correction applied for multiple comparisons.

RESULTS

There were 4.5% (1316 of 29138 [95% confidence interval {CI}: 4.3%, 4.8%]) of outpatient chest radiographic examinations that contained a recommendation for chest CT examination, and increasing patient age (P < .001) and positive smoking history (P = .001) were associated with increased likelihood of a recommendation for chest CT examination. Of patients within this subset who met inclusion criteria, 65.4% (691 of 1057 [95% CI: 62.4%, 68.2%) underwent a chest CT examination within the year after the index chest radiographic examination. Clinically relevant corresponding abnormalities were present on chest CT images in 41.4% (286 of 691 [95% CI: 37.7%, 45.2%]) of cases, nonclinically relevant corresponding abnormalities in 20.6% (142 of 691 [95% CI: 17.6%, 23.8%]) of cases, and no corresponding abnormalities in 38.1% (263 of 691 [95% CI: 34.4%, 41.8%]) of cases. Newly diagnosed, biopsy-proven malignancies were detected in 8.1% (56 of 691 [95% CI: 6.2%, 10.4%]) of cases.

CONCLUSION

A radiologist recommendation for chest CT to evaluate an abnormal finding on an outpatient chest radiographic examination has a high yield of clinically relevant findings.

Diagnosis and management of pulmonary nodules

There are an increased number of pulmonary nodules discovered on CT scan images in part due to those performed for lung cancer screening. Risk stratification and patient involvement is critical in determining management ranging from interval imaging to invasive biopsy or surgery. A definitive diagnosis requires tissue biopsy. The choice of a particular biopsy technique depends on the risks/benefits of the procedure, the diagnostic yield and local expertise. This review will focus on the evaluation and management of pulmonary nodules based on the Fleischner Society and American College of Chest Physician guidelines. There have been recent changes to both societies' recommendations for incidental detection of solid and subsolid nodules, risk stratification, imaging, minimally invasive diagnostic techniques and definitive surgical options.

The assessment of the role of baseline low-dose CT scan in patients at high risk of lung cancer

BACKGROUND

Despite the progress in contemporary medicine comprising diagnostic and therapeutic methods, lung cancer is still one of the biggest health concerns in many countries of the world. The main purpose of the study was to evaluate the detection rate of pulmonary nodules and lung cancer in the initial, helical low-dose CT of the chest as well as the analysis of the relationship between the size and the histopathological character of the detected nodules.

MATERIAL/METHODS

We retrospectively evaluated 1999 initial, consecutive results of the CT examinations performed within the framework of early lung cancer detection program initiated in Szczecin. The project enrolled persons of both sexes, aged 55-65 years, with at least 20 pack-years of cigarette smoking or current smokers. The analysis included assessment of the number of positive results and the evaluation of the detected nodules in relationship to their size. All of the nodules were classified into I of VI groups and subsequently compared with histopathological type of the neoplastic and nonneoplastic pulmonary lesions.

RESULTS

Pulmonary nodules were detected in 921 (46%) subjects. What is more, malignant lesions as well as lung cancer were significantly, more frequently discovered in the group of asymptomatic nodules of the largest dimension exceeding 15 mm.

CONCLUSIONS

The initial, low-dose helical CT of the lungs performed in high risk individuals enables detection of appreciable number of indeterminate pulmonary nodules. In most of the asymptomatic patients with histopathologically proven pulmonary nodules greater than 15 mm, the mentioned lesions are malignant, what warrants further, intensified diagnostics.

Evaluation and management of pulmonary nodules: state-of-the-art and future perspectives

INTRODUCTION

The imaging evaluation of pulmonary nodules, often incidentally detected on imaging examinations performed for other clinical reasons, is a frequently encountered clinical circumstance. With advances in imaging modalities, both the detection and characterization of pulmonary nodules continue to evolve and improve.

AREAS COVERED

This article will review the imaging modalities used to detect and diagnose benign and malignant pulmonary nodules, with a focus on computed tomography (CT), which continues to be the mainstay for evaluation. The authors discuss recent advances in the lung nodule management, and an algorithm for the management of indeterminate pulmonary nodules.

EXPERT OPINION

There are set of criteria that define a benign nodule, the most important of which are the lack of temporal change for 2 years or more, and certain benign imaging criteria, including specific patterns of calcification or the presence of fat. Although some indeterminate pulmonary nodules are immediately actionable, generally those approaching 1 cm or larger in diameter, at which size the diagnostic accuracy of tools such as positron emission tomography (PET)/CT, single photon emission CT (SPECT) and biopsy techniques are sufficient to warrant their use. The majority of indeterminate pulmonary nodules are under 1 cm, for which serial CT examinations through at least 2 years for solid nodules and 3 years for ground-glass nodules, are used to demonstrate either benign biologic behavior or otherwise. The management of incidental pulmonary nodules involves a multidisciplinary approach in which radiology plays a pivotal role. Newer imaging and postprocessing techniques have made this a more accurate technique eliminating ambiguity and unnecessary follow-up.

Incidentally detected lung nodules: clinical predictors of adherence to Fleischner Society surveillance guidelines

OBJECTIVE

The objective of this study was to determine adherence to incidentally detected lung nodule computed tomographic (CT) surveillance recommendations and identify demographic and clinical factors that increase the likelihood of CT surveillance.

MATERIALS AND METHODS

A total of 419 patients with incidentally detected lung nodules were included. Recorded data included patient demographic, radiologic, and clinical characteristics and outcomes at a 4-year follow-up. Multivariate logistic regression models determined the factors associated with likelihood of recommended CT surveillance.

RESULTS

At least 1 recommended surveillance chest CT was performed on 48% of the patients (148/310). Computed tomographic result communication to the patient (odds ratio [OR], 2.2; P = 0.006; confidence interval [CI], 1.3-4.0) or to the referring physician (OR, 2.8; P = 0.001; CI, 1.7-4.5) and recommendation of a specific surveillance time interval (OR, 1.7; P = 0.023; CI, 1.08-2.72) increased the likelihood of surveillance. Other demographic, radiologic, and clinical factors did not influence surveillance.

CONCLUSIONS

Documented physician and patient result communication as well as the recommendation of a specific surveillance time interval increased the likelihood of CT surveillance of incidentally detected lung nodules.

Proposal to utilize simplified Swensen protocol in diagnosis of isolated pulmonary nodule

BACKGROUND

The problem of diagnosing whether a solitary pulmonary nodule is benign or malignant is even greater in developing countries due to a higher prevalence of infectious diseases. These infections generate a large number of patients who are generally asymptomatic and with a pulmonary nodule that cannot be accurately defined as having benign or malignant etiology.

PURPOSE

To verify the percentages of benign versus malignant non-calcified nodules, the length of time after contrast agent injection is spiral computed tomography (CT) most sensitive and specific, and whether three postcontrast phases are necessary.

MATERIAL AND METHODS

We studied 23 patients with solitary pulmonary nodules identified on chest radiographs or CT. Spiral scans were obtained with Swensen protocol, but at 3, 4, and 5 min after contrast injection onset. Nodules were classified as benign or malignant by histopathological examination or by an absence or presence of growth after 2 years of follow-up CT.

RESULTS

Of the 23 patients studied, 18 (78.2%) showed a final diagnosis of benign and five (21.7%) malignant nodules. Despite the small sample size, we obtained results similar to those of Swensen et al., with 80.0% sensitivity, 55.5% specificity, and 60.8% accuracy. Four minutes gave the greatest mean enhancement in both malignant and benign lesions.

CONCLUSION

Small non-calcified benign nodules were much more frequent than malignant nodules. The best time for dynamic contrast-enhanced CT density analysis was 4 min postcontrast. As well as saving time and money, this simplified Swensen protocol with only precontrast and 4 min postcontrast phases also reduces patient exposure to ionizing radiation.

Evaluation of individuals with pulmonary nodules: when is it lung cancer? Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines

OBJECTIVES

The objective of this article is to update previous evidence-based recommendations for evaluation and management of individuals with solid pulmonary nodules and to generate new recommendations for those with nonsolid nodules.

METHODS

We updated prior literature reviews, synthesized evidence, and formulated recommendations by using the methods described in the "Methodology for Development of Guidelines for Lung Cancer" in the American College of Chest Physicians Lung Cancer Guidelines, 3rd ed.

RESULTS

We formulated recommendations for evaluating solid pulmonary nodules that measure > 8 mm in diameter, solid nodules that measure ≤ 8 mm in diameter, and subsolid nodules. The recommendations stress the value of assessing the probability of malignancy, the utility of imaging tests, the need to weigh the benefits and harms of different management strategies (nonsurgical biopsy, surgical resection, and surveillance with chest CT imaging), and the importance of eliciting patient preferences.

CONCLUSIONS

Individuals with pulmonary nodules should be evaluated and managed by estimating the probability of malignancy, performing imaging tests to better characterize the lesions, evaluating the risks associated with various management alternatives, and eliciting their preferences for management.

The long-term course of ground-glass opacities detected on thin-section computed tomography

BACKGROUND

Focal ground-glass opacity (GGO) is becoming a major concern because of its possible association with lung cancer. In this study, we analyzed the long-term progression of GGOs that persisted for more than 2 years.

METHODS

We reviewed focal GGOs identified by thin-section computed tomography that persisted for more than 2 years.

RESULTS

We enrolled a total of 114 patients with 175 GGO lesions. The median patient age was 61 years (range, 37-92 years) and 42 (36.8%) patients were male. Mean initial GGO size was 7.8 ± 4.4 mm. Median follow-up duration was 45 months. Forty-six (26.3%) GGOs had significant size increases (≥2 mm in the longest diameter) with a mean volume doubling time of 1041 days. In a multivariate analysis, large size (≥10 mm), the presence of a solid portion (mixed GGO) and old age (≥65 years) were risk factors for significant size increase, with odds ratios (95% CI) of 6.46 (2.69-15.6), 2.69 (1.11-6.95) and 2.55 (1.13-5.77), respectively. GGOs with character changes from pure to mixed or mixed to solid showed more rapid volume expansion.

CONCLUSIONS

GGOs which persisted for several years showed an indolent course. Large lesions with a solid portion and GGOs in male or elderly individuals may be cause for more concern, as these factors were associated with size increase. Resection should be considered if GGOs show character changes, as these may be associated with rapid size progression.

Roles of computed tomography and [(18)F]fluorodeoxyglucose-positron emission tomography/computed tomography in the characterization of multiple solitary solid lung nodules

The purpose of this study is to compare the performance of multidetector computed tomography (CT) and positron emission tomography/CT (PET/CT) with [(18)F]fluorodeoxyglucose in the diagnosis of multiple solitary lung nodules in 14 consecutive patients with suspicious lung cancer. CT and PET/CT findings were reviewed by a radiologist and nuclear medicine physician, respectively, blinded to the pathological diagnoses of lung cancer, considering nodule size, shape, and location (CT) and maximum standardized uptake value normalized to body weight (SUVbw max). Nodules were judged malignant or benign. The sensitivity, specificity, and accuracy of the two techniques were compared. CT had a sensitivity, specificity, and accuracy of 93.7, 86.7, and 90.3%, respectively, whereas PET/CT had a sensitivity, specificity, and accuracy of 75, 100, and 87.1%, respectively. Clinical management would have been erroneous in two patients by CT alone and in four patients by PET/CT alone. In one patient, the two techniques misdiagnosed the nodules (2 CT and 1 PET/CT). CT and PET/CT have complimentary roles in characterization of multiple solitary pulmonary nodules. Small nodules are poorly characterized by CT, and small-sized low-SUV malignant nodules are difficult to detect with PET/CT.

Surgical outcomes of lung cancer measuring less than 1 cm in diameter

OBJECTIVES

The increased use of computed tomography has led to an increasing proportion of lung cancers that are identified when still less than 1 cm in diameter. However, there is no defined treatment strategy for such cases. The aim of this study was to investigate the surgical outcomes of small lung cancers.

METHODS

A total of 143 patients were retrospectively evaluated, who had undergone a complete surgical resection for lung cancer less than 1 cm in diameter between January 1995 and December 2011.

RESULTS

The 143 study subjects included 62 male and 81 female patients. The mean age was 64.0 years (43-82 years). The mean tumour size was 0.8 cm (0.3-1.0 cm). Seventy-seven patients (53.8%) underwent lobectomy. Thirty-two patients (22.4%) underwent segmentectomy and 34 patients (23.8%) underwent wedge resection. The 3-, 5- and 10-year survival rates were 95.7, 92.2 and 85.7%, respectively, after resection for sub-centimetre lung cancer. There were no significant differences between sub-lobar resection and lobectomy. However, two patients (1.4%) had recurrent cancer and seven (4.9%) had lymph node metastasis.

CONCLUSIONS

The selection of the surgical procedure is important and a long-term follow-up is mandatory, because lung cancer of only 1 cm or less can be associated with lymph node metastasis and distant metastatic recurrence.

The clinical significance of radiologically detected indeterminate pulmonary nodules in colorectal cancer

AIM

Colorectal cancer patients identified with indeterminate pulmonary nodules (IPN) in the absence of other metastasis represent a clinical dilemma. This study aimed to identify characteristics that could predict which nodules truly represented a metastasis in an attempt to optimize therapy and to reduce the number of follow-up chest CT scans performed.

METHOD

All patients with colon or rectal cancer who presented between 2004 and 2008 were analysed. Patients with IPN on staging CT were identified from a dedicated prospective database and the medical records analysed and follow up recorded. Patients with obvious metastatic disease were excluded from analysis. Association of location, number and size of the nodules and metastatic disease were the primary end-points for analysis.

RESULTS

Nine hundred and eight patients presenting with cancer of the colon or rectum were identified. Thirty-seven (4%) patients were diagnosed with IPN with no obvious metastatic disease on staging CT. At a median follow up of 23 months there were eight (21%) cases where nodules had progressed. No significant association was detected between nodule size and pulmonary metastasis. Half of the patients with four or more nodules showed progression on serial CT imaging suggestive of pulmonary metastasis (χ(2), P ≤ 0.01).

CONCLUSION

Colorectal cancer patients with four or more indeterminate pulmonary nodules on preoperative staging CT imaging, even in the absence of metastasis elsewhere, are likely to represent pulmonary metastatic disease. These patients should be followed up with short-term interval CT imaging to enable early detection of progression so that treatment can be tailored appropriately.

Significance of pulmonary nodules in patients with colorectal cancer

OBJECTIVES

Radiographically small pulmonary nodules (PNs) in patients with colorectal cancer are troublesome because their discovery raises concern about metastases. This study sought to establish the appropriate timing of radiological follow-up for PNs detected at initial staging evaluation of colorectal carcinoma patients.

METHODS

The medical records of 376 consecutive colorectal cancer patients who underwent curative surgery and had baseline and follow-up chest X-rays (CXR) and computed tomography (CT) were reviewed.

RESULTS

The study included 92 patients who had all CXR and chest CT available for review, at least one PN found on baseline imaging, and no synchronous neoplasms. On baseline chest CT, these 92 patients had 170 PNs altogether and 77 (45.2 %) of them were greater than 5 mm in size. Baseline CXR detected 13 PNs in 12 patients and all but 2 were larger than 5 mm. Nodule size greater than 5 mm and irregular margins were predictors of nodule growth. The mean doubling time of 24/170 (14.1 %) growing PNs was about 4 months.

CONCLUSIONS

Our findings suggest that baseline and follow-up CXR are pointless, and short-interval CT follow-up is warranted when PNs larger than 5 mm with irregular margins are detected on preoperative chest CT.

KEY POINTS

• Pulmonary nodules in colorectal cancer patients raise concern about metastasis. • Baseline and follow-up chest X-ray in colorectal cancer can be abandoned. • CT is the best technique for assessing PNs in colorectal cancer. • Short-interval CT follow-up advisable for PNs larger than 5 mm with irregular margins.