Mediastinal nodes in bronchogenic carcinoma: comparison between CT and mediastinoscopy

Computed tomography (CT) and mediastinoscopy were compared in 151 patients with bronchogenic carcinoma. In all patients in whom findings at mediastinoscopy were negative, all accessible nodes were either removed or sampled at thoracotomy. Several size criteria for identifying nodes as enlarged on CT scans were compared. The long axis greater than or equal to 15 mm and short axis greater than 10 mm had very low sensitivity (61%), and the long axis greater than 5 mm had a low specificity (23%). CT (long axis greater than 10 mm) allowed sensitivity equal to that of mediastinoscopy (79%) in the detection of mediastinal metastases, but the specificity with CT was lower (65% vs. 100%). In seven of 44 patients with nodes greater than 10 mm on CT scans and with positive findings at mediastinoscopy, tumor was present not in the enlarged nodes but rather in normal-sized nodes in a different nodal station. The sensitivity of CT for actual nodal stations involved with tumor was only 66%. Eighty-three percent of patients with false-negative findings at mediastinoscopy but only 33% of patients with false-negative findings at CT had surgically resectable stage IIIa disease.     

The mediastinum in non-small cell lung cancer: CT-surgical correlation

Computed tomography was used to evaluate the mediastinum preoperatively in 60 patients with non-small cell lung cancer; 49 of these patients had thorough surgical-pathologic determination of mediastinal node status. Mediastinal lymph nodes were located by CT using the node-mapping scheme suggested by the American Thoracic Society and were considered abnormal when larger than 100 mm2 in cross-sectional area. The sensitivity of CT was 95% in detecting malignant mediastinal adenopathy; however, specificity was only 64%. Receiver operating characteristic (ROC) curve analysis showed that the optimal size criterion for diagnosing malignant mediastinal adenopathy is 1.0-1.5 cm when the short axis of a node is measured. CT staging of the mediastinum in patients with non-small cell lung cancer is clinically useful; negative mediastinal CT makes mediastinoscopy unnecessary, whereas positive CT should lead to biopsy of the enlarged node.     

Oblique hilar tomography, computed tomography, and mediastinoscopy for prethoracotomy staging of bronchogenic carcinoma

Preoperative oblique hilar tomography was used to evaluate hilar lymph nodes in 150 patients with clinically resectable bronchogenic carcinoma. CT was also used in the evaluation of mediastinal lymph nodes in 50 of these patients. Subsequently, all patients underwent mediastinoscopy and/or thoracotomy. Hilar and mediastinal nodes were evaluated for the presence of metastasis, and these findings were then correlated with the radiographic findings of oblique hilar tomography and CT. CT was found to be a reliable method for prethoracotomy staging of bronchogenic carcinoma and for selecting patients for mediastinoscopy. The sensitivity of CT for evaluation of mediastinal nodal metastasis was 83% and the specificity was 90%. Thus patients with negative mediastinal CT need not undergo mediastinoscopy prior to thoracotomy, while mediastinoscopy and biopsy should be done in patients with enlarged mediastinal nodes on CT. Oblique hilar tomography is an accurate method for evaluation of hilar adenopathy and for predicting mediastinal involvement by extrapolation.     

Metastases to pelvic lymph nodes from carcinoma in the pelvic cavity: diagnosis using thin-section CT

OBJECTIVE: To assess the accuracy of thin-section computed tomography (CT) in the diagnosis of pelvic lymph nodes affected by metastatic cancer. METHODS: Incremental CT was performed by obtaining 3 mm sections with 3 mm intervals in 34 patients who had carcinoma in the pelvis, pre-operatively and prospectively. CT diagnoses were made before surgery using the cine mode with a manual trackball. Lymph nodes with a maximum short axis diameter of greater than 5 mm were considered enlarged. RESULTS: The accuracy, sensitivity, specificity, positive and negative predictive values of CT diagnoses were 79.7%, 54.5%, 84.9%, 42.9% and 90.0% on a hemipelvis basis; and 79.4%, 85.7%, 77.8%, 50.0% and 95.5% on a patient basis, respectively. There was only one false-negative case on a patient basis analysis. CONCLUSION: Because of a fairly high negative predictive value, negative thin-section CT can be considered an alternative to surgical lymphadenectomy. This is clinically important as unnecessary staging operations and extended surgery are avoided.     

Assessment of cervical lymph node metastases using FDG-PET in patients with head and neck cancer

OBJECTIVE: To evaluate the diagnostic accuracy of fluorodeoxyglucose positron emission tomography (FDG-PET) relative to computed tomography (CT) for detecting metastatic cervical lymph nodes in patients with squamous cell carcinoma of the head and neck (HNSCC), and to ascertain the factors that affect this accuracy. METHODS: A total of 1076 lymph nodes obtained from 35 neck dissections in 26 HNSCC patients who preoperatively underwent both FDG-PET and CT were retrospectively analyzed. For pathological metastatic lymph nodes, the lymph node size (short-axis diameter), the ratio of intranodal tumor deposits, and the size of intranodal tumor deposits (maximum diameter of metastatic foci in each lymph node) were histologically recorded. RESULTS: Forty-six lymph nodes from 23 neck sides were pathologically diagnosed metastases. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of FDG-PET evaluated individually per neck side were 74%, 92%, 80%, 94%, and 65%, respectively, whereas those of CT were 78%, 58%, 71%, 78%, and 58%, respectively. FDG-PET detected 100% of metastatic lymph nodes > or =10 mm, intranodal tumor deposits > or =9 mm, and intranodal tumor deposits with a ratio >75%, whereas no nodes or tumor deposits smaller than 5 mm were detected. The spatial resolution limitations of FDG-PET were responsible for 16 of 20 (80%) false-negative PET results in lymph nodes. CONCLUSIONS: FDG-PET is a useful tool for preoperative evaluation of the neck because it accurately detects metastatic lymph nodes > or =10 mm and has fewer false-positive cases than CT. The high specificity of FDG-PET for lymph node metastases may play an important role in avoiding unnecessary neck dissection.     

Necrosis in metastatic neck nodes: diagnostic accuracy of CT, MR imaging, and US

PURPOSE: To compare the diagnostic accuracy of computed tomography (CT), magnetic resonance (MR) imaging, and ultrasonography (US) in the detection of necrosis in metastatic cervical nodes from patients with head and neck squamous cell carcinoma. MATERIALS AND METHODS: Twenty-seven patients (age range, 39-85 years; mean age, 62 years) with squamous cell carcinoma in the head and neck underwent CT, MR imaging, and US. Three radiologists evaluated the images for nodal necrosis. The results of each modality were analyzed for sensitivity, specificity, and accuracy. Pathologic analysis of the surgical resection served as the reference standard. The three modalities were compared for specificity and sensitivity with the McNemar test. RESULTS: Pathologic examination revealed 903 nodes, of which 89 were malignant. Of the malignant nodes, 43 were necrotic. Analysis of the detection of necrosis in the 89 malignant nodes showed an accuracy, sensitivity, and specificity of 92%, 91%, and 93% for CT; 91%, 93%, and 89% for MR imaging; and 85%, 77%, and 93% for US, respectively. All imaging modalities failed to depict necrotic areas of 3 mm or smaller in three nodes, and necrosis was missed in an additional seven nodes with US and in one node with CT. Necrosis could not be distinguished from other components of malignancy, such as viable tumor and scar tissue, in seven nodes (CT, 3; MR imaging, 5; US, 3). The sensitivity of both MR imaging and CT was significantly better than that of US (P =.0082 and P =.0339, respectively). There was no significant difference in sensitivity (P =.3173) between MR imaging and CT, or in the specificity of the three modalities. CONCLUSION: MR imaging is comparable to CT for the detection of necrosis. The sensitivity of MR imaging and CT is better than that of US.     

Computerized tomography in the staging of bronchogenic carcinoma. Critical evaluation of 91 cases

In reviewing 91 cases of bronchogenic carcinoma, traditional radiology (TR) and CT patterns were compared versus surgical/pathologic findings. CT always gave clearer assessment of the mediastinum and thoracic wall invasion. In the evaluation of metastatic spread to hilar and mediastinal lymph nodes the false negative rate was higher with TR than with CT; on the other hand, there was a higher false positive rate with CT. The advantage of CT in the staging of bronchogenic carcinoma is verified and a rationalized flow-chart which includes TR, endoscopy, CT and mediastinoscopy is suggested.     

FDG-PET in the Locoregional Lymph Node Staging of Non-small Cell Lung Cancer. A Comprehensive Review of the Leuven Lung Cancer Group Experience

Exact staging of locoregional lymph node (LN) disease in non-small cell lung cancer (NSCLC) is of considerable clinical interest. Computed tomography (CT) is not very accurate for this purpose. In the past years, we performed several prospective studies examining the role of [18F]fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) in this setting. We compared the accuracy of CT, PET, and PET read with the anatomical aid of CT images in the distinction of early-stage operable cases (i.e., without metastatic LN or with only hilar metastatic LN) versus locally advanced cases (with metastatic mediastinal LN). LNs on PET were recorded as metastatic if the FDG-uptake was more intense than the mediastinal blood pool activity. In 105 patients (or an analysis of 980 LN stations), the accuracy of PET (85%) was significantly better than that of CT (64%; P = 0.0003). Visual correlation with CT images further improved the results to an accuracy of 90%. We also examined the value of different acquisition protocols and interpretation algorithms. The use of Standardized Uptake Values (SUVs) of LNs, or of anatometabolic PET-CT-fusion images, did not prove to be of additional value compared to visual PET-reading and correlation with the CT images. On the condition that positive-LN findings on PET are always confirmed by mediastinoscopy, a simple whole-body acquisition protocol is adequate. We conclude that FDG-PET plays an important role in LN-staging in NSCLC. The very high negative predictive value of mediastinal FDG-PET is able to reduce the need for invasive surgical staging substantially.     

Prognostic importance of superior diaphragmatic adenopathy at computed tomography in patients with resectable hepatic metastases from colorectal carcinoma

PURPOSE: To determine the prognostic importance of superior diaphragmatic adenopathy at CT in patients with resectable hepatic metastases from colorectal carcinoma. MATERIALS AND METHODS: We retrospectively identified 85 patients who underwent contrast-enhanced abdominal computed tomography (CT) at our institution before surgical resection of hepatic metastases from colorectal carcinoma. The study group consisted of 45 men and 40 women with a mean age of 60 years (range, 27-89 years). The presence, size, and number of superior diaphragmatic nodes were recorded on preoperative CT images. Kaplan-Meier analysis was used to investigate the association between the presence, number, and size of superior diaphragmatic nodes and postoperative outcome. RESULTS: One or more superior diaphragmatic nodes were seen on preoperative CT in 43 (51%) of 85 patients, and 29 (34%) patients had nodes of 5 mm or more in short-axis diameter. After a median follow-up of 599 days (range, 3-1960 days), 49 patients were alive, and 36 were dead. Kaplan-Meier analysis showed no association between the presence (P = 0.67), size (P = 0.74), or number (P = 0.95) of superior diaphragmatic nodes and patient outcome. CONCLUSIONS: The presence, size, or number of superior diaphragmatic nodes at preoperative CT are unrelated to postoperative outcome in patients with resectable hepatic metastases from colorectal carcinoma, suggesting that superior diaphragmatic adenopathy in this setting may be reactive rather than metastatic.     

Radiologic evaluation of the subcarinal lymph nodes: a comparative study

Subcarinal lymph nodes are commonly involved by metastases from cancers of both the right and left lungs. No data exist on the relative accuracy of radiologic methods for evaluating subcarinal nodes. We prospectively studied lung cancer patients who were surgical candidates with CT, MR imaging (0.35 T), esophagography, and anteroposterior tomography. Forty-six patients who subsequently underwent thoracotomy had excision or sampling of subcarinal nodes at mediastinoscopy. All 46 had CT scans, 27 had MR imaging, 23 had esophagography, and 21 had anteroposterior tomography. Receiver-operating characteristic curves were constructed for each technique, and the area under each curve was calculated. MR and CT were nearly identical in subcarinal evaluation, with areas under the receiver-operating characteristic curves of 0.90 and 0.86, respectively; both were superior to esophagography (0.55) and anteroposterior tomography (0.61). The size threshold at which subcarinal nodes were considered abnormally enlarged in this lung cancer population was 11 mm in short axis for CT, agreeing with the size threshold previously reported for a normal population. The size threshold for abnormal nodal enlargement with MR imaging was 18 mm in short axis. We conclude that CT and MR imaging are comparable in the detection of subcarinal lymphadenopathy and are superior to both tomography and esophagography. Different size thresholds for metastatic subcarinal nodes are needed for CT and MR imaging to be comparable in overall performance.     

Lymph node metastasis in patients with clinical early-stage cervical cancer: detection with integrated FDG PET/CT

PURPOSE: To prospectively determine the accuracy of combination positron emission tomography-computed tomography (PET/CT) in lymph node staging in patients with early-stage cervical cancer, with histopathologic results as the reference standard. MATERIALS AND METHODS: The study was institutional review board approved, and all patients gave informed consent. Forty-seven consecutive women aged 29-71 years with clinical stage IA or IB cervical carcinoma were included in the study. All 47 patients were scheduled for radical hysterectomy with pelvic lymph node dissection. Before surgery, all patients underwent fluorine 18 fluorodeoxyglucose (FDG) PET/CT. PET/CT findings were interpreted by two readers in consensus and then compared with histopathologic results. At histopathologic examination, the dissected lymph nodes were classified as nonmetastatic or metastatic. RESULTS: Fifteen (32%) patients had metastatic lymph nodes at histopathologic examination, and 32 (68%) had no histopathologically confirmed nodal metastasis. Of the total 1081 lymph nodes histopathologically sampled, 18 were found to be positive for malignant cells. The overall node-based sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of PET/CT were 72% (13 of 18), 99.7% (1060 of 1063), 81% (13 of 16), 99.5% (1060 of 1065), and 99.3% (1073 of 1081), respectively. Corresponding values for PET/CT-based diagnosis of lymph nodes larger than 0.5 cm in diameter were 100% (13 of 13), 99.6% (675 of 678), 81% (13 of 16), 100% (675 of 675), and 99.6% (688 of 691), respectively. The overall patient-based sensitivity, specificity, PPV, NPV, and accuracy of PET/CT were 73% (11 of 15), 97% (31 of 32), 92% (11 of 12), 89% (31 of 35), and 89% (42 of 47), respectively. CONCLUSION: PET/CT proved to be valuable for lymph node staging in patients with early-stage cervical cancer, with short-axis diameter greater than 0.5 cm being the size threshold for accurate depiction of metastatic nodes.     

Bronchogenic carcinoma: analysis of staging in the mediastinum with CT by correlative lymph node mapping and sampling.

One hundred forty-three patients with bronchogenic carcinoma were studied prospectively with computed tomography (CT) to determine the accuracy of CT in the evaluation of mediastinal nodal metastases. Mediastinal lymph nodes were localized according to the lymph node mapping scheme of the American Thoracic Society and were considered abnormal if they exceeded 1 cm in short-axis diameter. All patients underwent surgical staging, which consisted of either mediastinoscopy alone or mediastinoscopy and thoracotomy. At the time of surgical staging, all accessible nodes were either removed or sampled. The sensitivity of CT for mediastinal nodes on a per-patient basis was 64%, with a specificity of 62%. The sensitivity of CT for individual nodal stations involved with tumor was only 44%. The presence of obstructive pneumonitis did not appreciably alter the sensitivity of CT, but the specificity was lower (43%). The likelihood of metastases increased with lymph node size; however, seven of 19 (37%) lymph nodes that measured 2-4 cm in short-axis diameter were hyperplastic and did not contain metastases. The relative insensitivity of CT makes formal nodal sampling at the time of mediastinoscopy or thoracotomy essential to detect lymph node metastases.     

Evaluation of the "N" factor in nonsmall cell lung cancer. Correlation between computerized tomography and pathologic anatomy

PURPOSE: To evaluate the role of CT in identifying other morphological signs of metastatic lymph node involvement from non small cell bronchogenic carcinoma. This is done to improve N staging, a critical step in this disease. In fact, since diameter is the only criterion used to distinguish normal form abnormal lymph nodes, medistinal CT only has 80% diagnostic accuracy. MATERIAL AND METHODS: 137 patients with known or suspected lung cancer were examined with Helical CT during early and late arterial phases (2 min delay, 3 mm thickness, 5 mm interslice gap) to depict node characteristics. Mediastinal lymph nodes, located according to the American Thoracic Society mapping, were considered normal when they were not visible or, if visible, less than 1 cm in diameter and of homogeneous density; lymph nodes over 1 cm in diameter and homogeneous density were considered reactive. A lymph node was considered metastatic when, independent of size, the following signs were found: central hypodensity; hyperdense thin/thick rim, with nodules within; hyperdense strands or diffuse hyperdensity in perinodal adipose tissue. The tumor site was also considered. RESULTS: Seventy patients were excluded because they were inoperable. Sixty-five of the remaining 67 patients were operated on, 1 underwent mediastinoscopy and another one mediastinoscopy followed by surgery. Based on the above CT signs, 46 patients were staged as N0, 61 as N1 and 15 as N2. In 44/46 N0 patients there was agreement between anatomical and pathologic findings; 3 of the 44 patients had lymph nodes over 1 cm in diameter and with homogeneous density. Micrometastases to mediastinal lymph nodes (N2) were found at histology in 2/46 patients (CT false negatives). In the 6 N1 and the 15 N2 patients there was complete agreement between anatomical and pathologic findings; in particular, 9 N2 patients had lymph nodes less than 1 cm in diameter with signs of metastasis and 4 had lymph nodes over 1 cm in diameter with signs of metastasis and 2 had lymph nodes either over or less than 1 cm. In all N2 patients the tumor histotype and the mediastinal location were also considered relative to the lesion site. DISCUSSION: A closer correlation was found with node morphology and density than with size. Indeed, CT sensitivity, specificity and diagnostic accuracy were 97, 100 and 97%, respectively, for the former versus 52, 93 and 77% for the latter. Adenocarcinoma was the predominant histotype (70.5%) in N2 patients. Metastases to node region 4 were predominant in right upper lobe carcinomas while node region 5 was predominant in left upper lobe lesions. CONCLUSIONS: Other criteria can be associated with size to improve CT diagnostic accuracy in N staging. Technique optimization plays a major role particularly in the late, thin slice, examination phase.     

An evaluation of computed tomography as an aid to diagnosis in patients undergoing bronchoscopy for suspected bronchial carcinoma

AIM: To determine whether computed tomography (CT) can predict the likelihood of obtaining a positive tissue diagnosis at fibreoptic bronchoscopy (FOB), or demonstrate an alternative means of achieving a tissue diagnosis, in patients presenting with a high clinical suspicion of primary bronchogenic carcinoma and an abnormal chest radiograph (CXR). MATERIALS AND METHODS: Sixty-two patients presenting with a high clinical suspicion of carcinoma and an abnormal CXR had chest and liver CT and FOB performed. All patients subsequently had histocytological confirmation of malignancy. Features recorded from the CTs included: the site and characteristics of a mass if present, and its relationship to adjacent airways; the presence of presumed metastatic disease; and a CT prediction of the likelihood of positive FOB was made. RESULTS: Of the patients, 41/62 (66%) had inoperable stage IIIb/IV disease. Fibreoptic biopsy yielded positive tissue diagnoses in 38/62 (61%). Computed tomography features predicting a positive FOB in this group included: ill-definition of the mass (12/15, 80%); a mass <4 cm from the origin of the nearest lobar bronchus (36/53, 68%); an endobronchial component of mass (22/24, 92%); a segmental or larger airway leading to the mass (30/35, 86%). Overall, CT had positive and negative predictive values for positive FOB of 85% and 78% respectively. The accuracy of the overall CT prediction of positive FOB was better than the accuracy of any of the individual factors. Seventeen of 62 (27%) patients had presumed metastatic disease suitable for percutaneous biopsy. CONCLUSION: Computed tomography is useful in predicting the likelihood of achieving positive histocytology at FOB. The overall CT prediction is superior to any of the individual CT features taken alone.Bungay, H. K. (2000). Clinical Radiology 55, 554-560.     

CT and pathologic assessment of prospective nodal staging in patients with ductal adenocarcinoma of the head of the pancreas

OBJECTIVE: The aim of our study was to compare the assessment of peripancreatic lymph nodes using CT with the gold standard of detailed histopathologic assessment of resected specimens in patients with pancreatic ductal adenocarcinoma. SUBJECTS AND METHODS: Sixty-two patients with presumed pancreatic carcinoma were prospectively studied with dual-phase contrast-enhanced helical CT, and images were interpreted in consensus by three radiologists. Complete surgical resection was performed in 28 patients. A detailed nodal classification system was used for radiologic, surgical, and pathologic staging in the nine patients whose final diagnosis at histology was pancreatic ductal adenocarcinoma. RESULTS: Forty lymph nodes were prospectively identified on CT in these nine patients. Two of 23 nodes (9%) measuring less than 5 mm in the short-axis diameter were malignant, four of 11 nodes (36%) measuring 5-10 mm were malignant, and one of six nodes (17%) larger than 10 mm was malignant. Using a short-axis diameter of greater than 10 mm as the criterion for nodal involvement, we found a sensitivity of 14% (1/7) and a specificity of 85% (28/33), with a positive predictive value of 17% (1/6), a negative predictive value of 82% (28/34), and an overall accuracy of 73% (29/40). Ovoid nodal shape, clustering of nodes, and the absence of a fatty hilum were not useful predictors of malignancy on CT. CONCLUSION: In resectable pancreatic ductal adenocarcinoma, CT is not accurate overall for the prediction of nodal involvement. In a patient with presumed pancreatic carcinoma that is considered to be resectable, the depiction on CT of peripancreatic nodes should not prevent attempted curative resection.     

Comparison of dynamic helical CT and dynamic MR imaging in the evaluation of pelvic lymph nodes in cervical carcinoma

OBJECTIVE: This study compares dynamic helical CT with dynamic MR imaging in the evaluation of pelvic lymph nodes in cervical carcinoma. SUBJECTS AND METHODS: Women with biopsy-proven cervical carcinoma prospectively underwent dynamic helical CT and MR imaging before surgery. A metastatic node on CT and MR imaging was defined as a rounded soft-tissue structure greater than 10 mm in maximal axial diameter or a node with central necrosis. Imaging results were compared with pathology, and receiver operating characteristic curves for size and shape were plotted on a hemipelvis basis. Nodal density and signal intensity on CT and MR images, respectively, were reviewed for differences between benign and malignant disease. RESULTS: A total of 949 lymph nodes were found at pathology in 76 hemipelves in 43 women, of which 69 lymph nodes (7%) in 17 hemipelves (22%) were metastatic. Sensitivity, specificity, positive and negative predictive values, and accuracy of helical CT and MR imaging in the diagnosis of lymph node metastasis on a hemipelvis basis was 64.7%, 96.6%, 84.6%, 90.5%, and 89.5% and 70.6%, 89.8%, 66. 7%, 91.4%, and 85.5%, respectively. Receiver operating characteristic curves for helical CT and MR imaging gave cutoff values of 9 and 12 mm in maximal axial diameter, respectively, in the prediction of metastasis. Central necrosis had a positive predictive value of 100% in the diagnosis of metastasis. Signal intensity on MR imaging and density-enhancement pattern on CT in patients with metastatic nodes did not differ from those in patients with negative nodes. CONCLUSION: Helical CT and MR imaging show similar accuracy in the evaluation of pelvic lymph nodes in patients with cervical carcinoma. Central necrosis is useful in the diagnosis of metastasis in pelvic lymph nodes in cervical cancer.     

Computed tomography of mediastinal lymph nodes in nonsmall cell lung cancer. A new approach based on the lymphatic pathway of tumor spread

Computed tomography was used to evaluate mediastinal lymph nodes in 97 patients with nonsmall cell lung cancer. All patients had thorough surgical-pathological determination of mediastinal node status. Twenty-three patients were found to have metastatic lymph nodes. The usual lymphatic pathways of tumor spread into the mediastinum were defined using the node mapping scheme suggested by the American Thoracic Society. We considered mediastinal nodes abnormal when the short axis of the largest mediastinal node in the lymphatic drainage territory of the cancer was greater than or equal to 10 mm and the difference between this node and the largest node in the other territories is greater than 5 mm. The sensitivity was 78%, the specificity 99%, the positive predictive value 95%, the negative predictive value 94%, and the accuracy 94%. Comparing our method to those that used the size criterion alone, the number of false positives was reduced.     

Mediastinal staging of non-small cell bronchial carcinoma. The place of computed tomography and mediastinoscopy

Sixty patients with a potentially resectable non-oat-cell lung carcinoma were examined by computed tomography and cervical mediastinoscopy. The sensitivity of computed tomography as opposed to mediastinoscopy was 74% versus 58% and the specificity in 85% versus 100%. Considering the limitations of both methods and the varying prevalence of mediastinal lymph-node metastases associated with peripheral and central lesions, three different situations can be distinguished: 1. with peripheral lesions and a normal mediastinal CT, preoperative mediastinoscopy is unnecessary. 2. With an abnormal mediastinal CT, mediastinoscopy is always indicated irrespective of the location of the tumor. 3. With large central lesions, mediastinoscopy is necessary even when the CT is normal. Using these rules, 37 of 60 mediastinoscopies in our patient group could have been avoided without influencing the resection rate (98%).     

Improved radiologic staging of lung cancer with 2-[18F]-fluoro-2-deoxy-D-glucose-positron emission tomography and computed tomography registration

PURPOSE: To determine if volumetric nonlinear registration or registration of thoracic computed tomography (CT) and 2-[18F]-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) datasets changes the detection of mediastinal and hilar nodal disease in patients undergoing staging for lung cancer and if it has any impact on radiologic lung cancer staging. METHOD: Computer-based image registration was performed on 45 clinical thoracic helical CT and FDG-PET scans of patients with lung cancer who were staged by mediastinoscopy and/or thoracotomy. Thoracic CT, FDG-PET, and registration datasets were each interpreted by 2 readers for the presence of metastatic nodal disease and were staged independently of each other. Results were compared with surgical pathologic findings. RESULTS: One hundred and thirty lymph node stations in the mediastinum and hila were evaluated each on CT, PET, and registration datasets. Sensitivity, specificity, positive predictive value, and negative predictive value, respectively, for detecting metastatic nodal disease for CT were 74%, 78%, 55%, 88%; for PET with CT side by side, 59% to 76%, 77% to 89%, 48% to 68%, and 84% to 91%; and for CT-PET registration, 71% to 76%, 89% to 96%, 70% to 86%, and 90% to 91%. Registration images were significantly more sensitive in detecting nodal disease over PET for 1 reader (P = 0.0156) and were more specific than PET (P = 0.0107 and 0.0017) in identifying the absence of mediastinal disease for both readers. Registration was significantly more accurate for staging when compared with PET for both readers (P = 0.002 and 0.035). CONCLUSION: Registration of CT and FDG-PET datasets significantly improved the specificity of detecting metastatic disease. In addition, registration improved the radiologic staging of lung cancer patients when compared with CT or FDG-PET alone.     

Targeted lymph node biopsy in mediastinoscopy using 3D FDG-PET/CT movies: a feasibility study

In non-small-cell lung cancer, positive lymph nodes with increased fluorodeoxyglucose (FDG) uptake may be missed by mediastinoscopy. Lack of pathological confirmation may lead to radical, but unnecessary lung surgery. To minimize these false-negative results, the feasibility and potential value of three-dimensional (3D) FDG-PET/computed tomography (CT) movies were investigated to improve targeted lymph node biopsy during mediastinoscopies. PET/CT images were rendered in 3D volumes with multiplanar reconstructions and maximum intensity projections and reviewed in 3D 'fly-through' and 'fly-around' movies. These movies were developed and optimized by the Departments of Surgery and Nuclear Medicine. Twenty-two consecutive patients with non-small-cell lung cancer were included, of whom eight were FDG-PET positive for mediastinal lymph nodes. 3D FDG-PET/CT movies were presented to surgeons before mediastinoscopy. Surgical consequences were investigated, including sensitivity and the negative predictive value of mediastinoscopy. Results were compared with those of a retrospective study in which 3D techniques were not used. During mediastinoscopies, the 3D-PET/CT movies were found to be helpful in the surgical localization of FDG-positive lymph nodes. It led to more confidence in the surgical approach. The sensitivity and negative predictive value were 86 and 94%, respectively. Although not statistically significant, these results were higher compared with those of the retrospective study (75 and 92%, respectively). 3D FDG-PET/CT guidance during mediastinoscopy is feasible. The movies seem to lead to targeted biopsy of lymph nodes. They may reduce false-negative mediastinoscopies and improve staging of lung cancer. 3D FDG-PET/CT can be seen as a promising tool for further implementation of image-guided surgery.