Imaging of lung cancer with CT, MRT and PET

Can MRI differentiate surrounding vertebral invasion from reactive inflammatory changes in superior sulcus tumor?

OBJECTIVES

Vertebral invasion is a key prognostic factor and a critical aspect of surgical planning for superior sulcus tumors. This study aims to further evaluate MRI features of vertebral invasion in order to distinguish it from reactive inflammatory changes.

METHODS

Between 2000 and 2016, a retrospective study was performed at a single institution. All patients with superior sulcus tumors undergoing surgery, including at least two partial vertebrectomies, were included. An expert radiologist evaluated qualitative and quantitative MRI signal intensity characteristics (contrast-to-noise ratio [CNR]) of suspected involved and non-involved vertebrae. A comparison of CNR of invaded and sane vertebrae was performed using non-parametric tests. Imaging data were correlated with pathological findings.

RESULTS

A total of 92 surgical samples of vertebrectomy were analyzed. The most specific sequences for invasion were T1 and T2 weighted (92% and 97%, respectively). The most sensitive sequences were contrast enhanced T1 weighted fat suppressed and T2 weighted fat suppressed (100% and 80%). Loss of extrapleural paravertebral fat on the T1-weighted sequence was highly sensitive (100%) but not specific (63%). Using quantitative analysis, the optimum cut-off (p < 0.05) to distinguish invasion from reactive inflammatory changes was CNR > 11 for the T2-weighted fat-sat sequence (sensitivity 100%), CNR > 9 for contrast-enhanced T1-weighted fat-suppressed sequence (sensitivity 100%), and CNR < - 30 for the T1-weighted sequence (specificity 97%). Combining these criteria, 23 partial vertebrectomies could have been avoided in our cohort.

CONCLUSION

Qualitative and quantitative MRI analyses are useful to discriminate vertebral invasion from reactive inflammatory changes.

KEY POINTS

• Abnormal signal intensity in a vertebral body adjacent to a superior sulcus tumor may be secondary to direct invasion or reactive inflammatory changes. • Accurate differentiation between invasion and reactive inflammatory changes significantly impacts surgical planning. T1w and T2w are the best sequences to differentiate malignant versus benign bone marrow changes. The use of quantitative analysis improves MRI specificity. • Using contrast media improves the sensitivity for the detection of tumor invasion.

Neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios may aid in identifying patients with non-small cell lung cancer and predicting Tumor-Node-Metastasis stages

The present study aimed to identify a high-risk population with non-small cell lung cancer (NSCLC) and to predict TNM stages using the neutrophil-to-lymphocyte ratio (NLR) and the platelet-to-lymphocyte ratio (PLR). This retrospective study included preoperative data of 171 patients and 105 controls. Compared with healthy controls, patients with NSCLC had higher levels of NLR and PLR (NLR, 2.719±0.183 vs. 1.813±0.079, P<0.01; PLR, 135.800±4.778 vs. 112.000±5.651, P<0.01, respectively). The associations between Tumor-Node-Metastasis stages and the aforementioned parameters were detected (both P<0.01). NLR and PLR improved the rate of early diagnosis of NSCLC, particularly for stages III and IV with a higher area under curve value (0.752 and 0.759, respectively) compared with stage I and II NSCLC. In addition, PLR with a T stage-dependent increase may be a potential and independent predictive marker for T stage (P<0.05); the NLR exhibited an N stage-dependent increase (except for stage N3) and was identified as a marker for N stage (P<0.0001). It was subsequently concluded that NLR and PLR are useful biomarkers in the early diagnosis of NSCLC; that these two parameters were capable of indicating advanced stages, III and IV; and that PLR and NLR were independent predictors for T and N stages, respectively.

Neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios may aid in identifying patients with non-small cell lung cancer and predicting Tumor-Node-Metastasis stages

The present study aimed to identify a high-risk population with non-small cell lung cancer (NSCLC) and to predict TNM stages using the neutrophil-to-lymphocyte ratio (NLR) and the platelet-to-lymphocyte ratio (PLR). This retrospective study included preoperative data of 171 patients and 105 controls. Compared with healthy controls, patients with NSCLC had higher levels of NLR and PLR (NLR, 2.719±0.183 vs. 1.813±0.079, P<0.01; PLR, 135.800±4.778 vs. 112.000±5.651, P<0.01, respectively). The associations between Tumor-Node-Metastasis stages and the aforementioned parameters were detected (both P<0.01). NLR and PLR improved the rate of early diagnosis of NSCLC, particularly for stages III and IV with a higher area under curve value (0.752 and 0.759, respectively) compared with stage I and II NSCLC. In addition, PLR with a T stage-dependent increase may be a potential and independent predictive marker for T stage (P<0.05); the NLR exhibited an N stage-dependent increase (except for stage N3) and was identified as a marker for N stage (P<0.0001). It was subsequently concluded that NLR and PLR are useful biomarkers in the early diagnosis of NSCLC; that these two parameters were capable of indicating advanced stages, III and IV; and that PLR and NLR were independent predictors for T and N stages, respectively.

Diagnostic efficacy of PET and PET/CT for recurrent lung cancer: a meta-analysis

BACKGROUND

Lung cancer is one of the most common malignant tumors in the world, and is the leading cause of cancer-related mortality. Although there are no conclusive data to support the survival benefits of early detection or early treatment for recurrence, an early and accurate diagnosis of recurrence is critical to optimize therapy.

PURPOSE

To compare the diagnostic value of positron emission tomography (PET) and positron emission tomography/computed tomography (PET/CT) using fluorine-18 deoxyglucose (18FDG) with conventional imaging techniques (CITs) for the detection of lung cancer recurrence.

MATERIAL AND METHODS

A meta-analysis was performed, with systematic searches conducted using PubMed and EMBASE databases (up to 31 December 2011). Pooled sensitivity, specificity, and diagnostic odds ratio (DOR) values were calculated for 1035 patients reported in 13 articles. Summary receiver-operating characteristic curves (SROC) were also generated.

RESULTS

The pooled sensitivity (95% CI) for PET, PET/CT, and CITs were 0.94 (0.91-0.97), 0.90 (0.84-0.95), and 0.78 (0.71-0.84), respectively. The pooled specificity (95% CI) for PET, PET/CT, and CITs were 0.84 (0.77-0.89), 0.90 (0.87-0.93), and 0.80 (0.75-0.84), respectively. Regarding sensitivity, lower values were associated with CITs than PET (P = 0.000) and PET/CT (P = 0.005), and there was no significant difference between PET/CT and PET (P = 0.102). Regarding specificity, values for PET/CT and PET were significantly higher than for CITs (both P = 0.000), and there was no significant difference between PET/CT and PET (P = 0.273). In the SROC curves, a better diagnostic accuracy was associated with PET/CT than PET and CITs.

CONCLUSION

PET/CT and PET were found to be superior modalities for the detection of recurrent lung cancer, and PET/CT was superior to PET.

Positron emission tomography: clinical applications in oncology. Part 1

Positron emission tomography is a functional diagnostic imaging technique, which can accurately measure in vivo distribution of a radiopharmaceutical with high resolution. The ability of positron emission tomography to study various biologic processes opens up new possibilities for both research and day-to-day clinical use. Positron emission tomography has progressed rapidly from being a research technique in laboratories to a routine clinical imaging modality becoming part of armamentarium for the medical profession. The most widely used radiotracer in positron emission tomography is 18F-fluoro-2-deoxy-D-glucose (FDG), which is an analog of glucose. FDG uptake in cells is directly proportional to glucose metabolism of cells. Since glucose metabolism is increased many fold in malignant tumors, positron emission tomography has a high sensitivity and high negative predictive value. Positron emission tomography with FDG is now the standard of care in initial staging, monitoring the response to therapy and management of lung cancer, colorectal cancer, lymphoma, melanoma, esophageal cancer, head and neck cancer and breast cancer. The aim of this article is to review the clinical applications of positron emission tomography in oncology.

Lymph node dissection--understanding the immunological function of lymph nodes

Lymph nodes (LN) are one of the important sites in the body where immune responses to pathogenic antigens are initiated. This immunological function induced by cells within the LN is an extensive area of research. To clarify the general function of LN, to identify cell populations within the lymphatic system and to describe the regeneration of the lymph vessels, the experimental surgical technique of LN dissection has been established in various animal models. In this review different research areas in which LN dissection is used as an experimental tool will be highlighted. These include regeneration studies, immunological analysis and studies with clinical questions. LN were dissected in order to analyse the different cell subsets of the incoming lymph in detail. Furthermore, LN were identified as the place where the induction of an antigen-specific response occurs and, more significantly, where this immune response is regulated. During bacterial infection LN, as a filter of the lymph system, play a life-saving role. In addition, LN are essential for the induction of tolerance against harmless antigens, because tolerance could not be induced in LN-resected animals. Thus, the technique of LN dissection is an excellent and simple method to identify the important role of LN in immune responses, tolerance and infection.

Combined PET/MRI: a new dimension in whole-body oncology imaging?

INTRODUCTION

Hybrid imaging systems providing morphological and functional data in a single session have been available for oncological imaging for some time. So far, computed tomography (CT) has been the morphological method-of-choice for inclusion into these hybrid imaging systems. However, recently, research has focused on hardware-based fusion of function with magnetic resonance imaging (MRI) rather than CT.

OBJECTIVES

Now that the first head-only positron emission tomography (PET)/MRI systems have been installed and whole-body systems are to be expected in the near future, potential indications in clinical oncology have to be addressed.

DISCUSSION

This article discusses potential indications of PET/MRI in whole-body oncology imaging. Potential advantages and disadvantages compared with currently available hybrid imaging systems will be reviewed.

Endoscopic ultrasound as a first test for diagnosis and staging of lung cancer: a prospective study

RATIONALE

Multiple tests are required for the management of lung cancer.

OBJECTIVES

Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) was evaluated as a single test for the diagnosis and staging (thoracic and extrathoracic) of lung cancer.

METHODS

Consecutive subjects with computed tomography (CT) findings of a lung mass were enrolled for EUS and results were compared with those from CT and positron emission tomography scans.

RESULTS

Of 113 subjects with lung cancer, EUS was performed as a first test (after CT scan) for diagnosis in 93 (82%) of them. EUS-FNA established tissue diagnosis in 70% of cases. EUS-FNA, CT, and positron emission tomography detected metastases to the mediastinal lymph nodes with accuracies of 93, 81, and 83%, respectively. EUS-FNA was significantly better than CT at detecting distant metastases (accuracies of 97 and 89%, respectively; p = 0.02). Metastases to lymph nodes at the celiac axis (CLNs) were observed in 11% of cases. The diagnostic yields of EUS-FNA and CT for detection of metastases to the CLNs were 100 and 50%, respectively (p < 0.05). EUS was able to detect small metastases (less than 1 cm) often missed by CT. Metastasis to the CLNs was a predictor of poor survival of subjects with non-small cell lung cancer, irrespective of the size of the CLNs. Of 44 cases with resectable tumor on CT scan, EUS-FNA avoided thoracotomy in 14% of cases.

CONCLUSIONS

EUS-FNA as a first test (after CT) has high diagnostic yield and accuracy for detecting lung cancer metastases to the mediastinum and distant sites. Metastasis to the CLNs is associated with poor prognosis. EUS-FNA is able to detect occult metastasis to the CLNs and thus avoids thoracotomy.

Fast T1- and T2-weighted pulmonary MR-imaging in patients with bronchial carcinoma

PURPOSE

A prospective study to evaluate the diagnostic potential and limitations of three fast MRI sequences in patients with bronchial carcinoma based on the comparison with spiral CT.

MATERIAL AND METHODS

Three fast chest MRI sequences from 20 patients with central or peripheral bronchial carcinoma were evaluated by two observers for relation of tumour to adjacent structures, lymph node enlargement, additional pulmonary lesions and artefacts. The information from MR-imaging was compared with the results from spiral CT. MRI comprised a T1-3D-GRE breath-hold examination ("VIBE", TR/TE 4.5/1.9 ms, flip-angle 12 degrees , matrix 502 x 512, 2.5 mm coronal slices), a breath-hold, T2-HASTE sequence (TR/TE 2000/43 ms, matrix 192 x 256, 10 mm coronal slices) and a respiration-triggered T2-TSE sequence (TR/TE 3000-6000/120 ms, matrix 270 x 512, 6 mm transverse slices). The FOV was adapted individually (380-480 mm).

RESULTS

The presence of the primary bronchial carcinoma and infiltration of thoracic structures by tumour tissue could be demonstrated by all sequences. VIBE sequence was more suitable for detecting small pulmonary nodules than the other MRI examinations, but compared to CT still 20% of these lesions were missed. Contrary to VIBE and T2-weighted TSE scans, HASTE sequence was limited in imaging mediastinal lymph nodes due to missing relevant findings in 2/20 patients. HASTE images significantly provided the lowest rate of artefacts in imaging lung parenchyma (P < 0.001 in peripheral parenchyma), but spatial resolution was limited in this sequence. Concerning the differentiation between tumour and adjacent atelectasis (n = 8), T2-weighted TSE imaging was superior to CT and VIBE in all cases and to HASTE sequence in 4/8 patients.

CONCLUSION

The combination of VIBE and HASTE sequence allows for an adaequate imaging of thoracic processes in patients with bronchial carcinoma, limited only in visualizing small pulmonary nodules. To obtain more detail resolution and to differentiate tumour tissue from adjacent atelectasis, T2-TSE examination may be added in selected cases.

Screening of brain metastasis with limited magnetic resonance imaging (MRI): clinical implications of using limited brain MRI during initial staging for non-small cell lung cancer patients

The purpose of this prospective study was to determine whether using magnetic resonance imaging (MRI) for early screening for brain metastases (BM) can improve quality of life, survival in patients with non-small cell lung cancer (NSCLC). The study group comprised 183 patients newly diagnosed with NSCLC. All patients underwent limited brain MRI and routine workups. The control group comprised 131 patients with NSCLC who underwent limited brain MRI only if they had neurologic symptoms. The incidence of BM was 20.8% (38/183) in the study group and 4.6% (6/131) in the control group. The rate of upstaging based on the MRI data was 13.5% (15/111) overall and 15.9% (11/69) in patients that had been considered initially to be resectable surgically. There was no significant difference in survival outcome between the groups. Patients who had BM alone had a greater overall survival time (49 weeks) than those who had multiple systemic metastases (27 weeks; p=0.0307). In conclusions, limited brain MRI appears to be a useful, cost-effective method to screen for BM at the time of initial staging. And it may facilitate timely treatment of patients with NSCLC and improve their survival and quality of life.

[Whole-body tumor staging: MRI or FDG-PET/CT?]

Technical innovations such as the availability of movable patient platforms and the introduction of 32-channel systems have made whole-body MRI for tumor staging feasible. In addition, the development of dual-modality PET/CT systems offers the opportunity to perform anatometabolic tumor staging with whole-body coverage in a single session. Based on an increase in patient survival when applying a stage-adapted therapy in different malignant diseases the relevant question relates to the accuracies of whole-body MRI and whole-body PET/CT for TNM staging. This review article addresses whole-body tumor staging with MRI and FDG-PET/CT with special emphasis on diagnostic accuracies for staging different malignant diseases.

Accuracy of whole-body dual-modality fluorine-18-2-fluoro-2-deoxy-D-glucose positron emission tomography and computed tomography (FDG-PET/CT) for tumor staging in solid tumors: comparison with CT and PET

PURPOSE

To assess the accuracy of positron emission tomography/computed tomography (PET/CT) when staging different malignant diseases.

PATIENTS AND METHODS

This was a retrospective, blinded, investigator-initiated study of 260 patients with various oncological diseases who underwent fluorine-18-2-fluoro-2-deoxy-d-glucose PET/CT for tumor staging. CT images alone, PET images alone, PET + CT data viewed side by side, and fused PET/CT images were evaluated separately according to the tumor-node-metastasis system. One hundred forty patients with tumors not staged according to the tumor-node-metastasis system or a lack of reference standard were excluded from data analysis; 260 patients were included. Diagnostic accuracies were determined for each of the four image sets. Histopathology and a clinical follow-up of 311 (+/- 125) days served as standards of reference.

RESULTS

PET/CT proved significantly more accurate in assessing tumor-node-metastasis system stage compared with CT alone, PET alone, and side-by-side PET + CT (P < .0001). Of 260 patients, 218 (84%; 95% CI, 79% to 88%) were correctly staged with PET/CT, 197 (76%; 95% CI, 70% to 81%) with side-by-side PET + CT, 163 (63%; 95% CI, 57% to 69%) with CT alone, and 166 (64%; 95% CI, 58% to 70%) with PET alone. Combined PET/CT had an impact on the treatment plan in 16, 39, and 43 patients when compared with PET + CT, CT alone, and PET alone, respectively.

CONCLUSION

Tumor staging with PET/CT is significantly more accurate than CT alone, PET alone, and side-by-side PET + CT. This diagnostic advantage translates into treatment plan changes in a substantial number of patients.

Current concepts in the mediastinal lymph node staging of nonsmall cell lung cancer

OBJECTIVE

To review the current concepts in the mediastinal staging of nonsmall cell lung cancer (NSCLC), evaluating traditional and modern staging modalities.

SUMMARY BACKGROUND DATA

Staging of NSCLC includes the assessment of mediastinal lymph nodes. Traditionally, computed tomography (CT) and mediastinoscopy are used. Modern staging modalities include magnetic resonance imaging (MRI), positron emission tomography (PET), and endoscopic ultrasound with fine-needle aspiration (EUS-FNA) METHODS: Literature was searched with PubMed and SUMSearch for original, peer-reviewed, full-length articles. Studies were evaluated on inclusion criteria, sample size, and operating characteristics. Endpoints were accuracy, safety, and applicability of the staging methods.

RESULTS

CT had moderate sensitivities and specificities. With few exceptions magnetic resonance imaging (MRI) offered no advantages when compared with CT, against higher costs. PET was significantly more accurate than CT. Mediastinoscopy and its variants were widely used as gold standard, although meta-analyses were absent. Percutaneous transthoracic needle biopsy (PTNB) and transbronchial needle biopsy (TBNA) were moderately sensitive and specific. EUS-FNA had high sensitivity and specificity, is a safe and fast procedure, and is cost-effective. EUS-FNA evaluates largely a nonoverlapping mediastinal area compared with mediastinoscopy.

CONCLUSIONS

PET has the highest accuracy in the mediastinal staging of NSCLC, but is not generally used yet. EUS-FNA has the potential to perform mediastinal tissue sampling more accurate than TBNA, PTNB, and mediastinoscopy, with fewer complications and costs. Although promising, EUS-FNA is still experimental. Mediastinoscopy is still considered as gold standard for mediastinal staging of NSCLC.

Bronchoscopy and surgical staging procedures and their correlation with imaging

Bronchoscopy, computed tomography (CT) and surgical staging procedures are complimentary methods of investigating patients with lung cancer. CT has been shown to be of value prior to bronchoscopy in the investigation of haemoptysis and malignancy, with excellent correlation between the detection of disease within the large airways on CT and direct visualisation at bronchoscopy. The utility of CT has been further increased by the development of multislice scanners with the generation of volumetric data enabling multiplanar image acquisition. Additionally the advent of CT co-registered with positron emission tomography will play an important role in guiding the choice of surgical staging procedures The increasing use of multidisciplinary medical care requires radiologists to have a greater understanding of the abilities and limitations of both bronchoscopy and surgical staging procedures in evaluating disease demonstrated on imaging.