Jeremy J. Erasmus

Interobserver and Intraobserver Variability in Measurement of Non–Small-Cell Carcinoma Lung Lesions: Implications for Assessment of Tumor Response

PURPOSE Response of solid malignancies to therapy is usually determined by serial measurements of tumor size. The purpose of our study was to assess the consistency of measurements performed by readers evaluating lung tumors. MATERIALS AND METHODS The study group was composed of 33 patients with lung tumors more than 1.5 cm. Bidimensional (BD) and unidimensional (UD) measurements were performed on computed tomography (CT) scans according to the World Health Organization (WHO) criteria and the Response Evaluation Criteria in Solid Tumors (RECIST), respectively. Measurements were performed independently by five thoracic radiologists using printed film and were repeated after 5 to 7 days. Inter- and intraobserver measurement variations were estimated through statistical modeling. RESULTS There were 40 tumors with an average size of 1.8 to 8.0 cm (mean, 4.1 cm). Analysis of variance showed a significant difference (P <.05) among readers and among the measured nodules for UD and BD measurements. Interobserver misclassification rates were more than intraobserver misclassification rates using either progressive disease or response criteria. The probability of misclassifying a tumor with the WHO criteria or RECIST was greatest with interobserver measurements when criteria for progression (43% BD, 30% UD) were used and lowest with intraobserver measurements when criteria for response (2.5% BD, 3.0% UD) were used. In addition, interobserver misclassification rates were more than intraobserver misclassification rates for both regular and irregular tumors. CONCLUSION Measurements of lung tumor size on CT scans are often inconsistent and can lead to an incorrect interpretation of tumor response. Consistency can be improved if the same reader performs serial measurements for any one patient.

Quantifying the Effect of IV Contrast Media on Integrated PET/CT: Clinical Evaluation

OBJECTIVES The use of IV contrast media in PET/CT can result in an overestimation of PET attenuation factors that potentially can affect interpretation. The objective of this study was to quantify the effect of IV contrast media in PET/CT and assess its impact on patients with intrathoracic malignancies. MATERIALS AND METHODS Nine patients had CTs performed with and without IV contrast media followed by (18)F-FDG PET. PET images were reconstructed using contrast-enhanced and unenhanced CT. To quantify the effect of contrast media on standardized uptake values (SUV), similar regions of interest (ROIs) were drawn on the subclavian vein, heart, liver, spleen, and site of malignancy on both CT and corresponding reconstructed PET images, and the mean and maximum values were compared. In addition, two physicians blinded to the imaging parameters that were used evaluated the reconstructed PET images to assess whether IV contrast media had an effect on clinical interpretation. RESULTS For all patient studies, the subclavian vein region on the ipsilateral side of contrast media administration had the highest increase in CT numbers with a corresponding average SUV(max) increase of 27.1%. Similarly, ROIs of the heart and at the site of malignancy showed an increase in the maximum attenuation value with a corresponding average SUV(max) increase of 16.7% and 8.4%, respectively. Other locations had relatively small attenuation value differences with a correspondingly negligible SUV variation. CONCLUSION Although there is a significant increase in SUV in regions of high-contrast concentration when contrast-enhanced CT is used for attenuation correction, this increase is clinically insignificant. Accordingly, in PET/CT, IV contrast-enhanced CT can be used in combination with the PET to evaluate patients with cancer.

Detection of interval distant metastases: clinical utility of integrated CT-PET imaging in patients with esophageal carcinoma after neoadjuvant therapy.

The objective of the study was to determine the utility of integrated computed tomography / positron emission tomography (CT‐PET) imaging for detecting interval distant metastases and assessing therapeutic response in patients with locally advanced, potentially resectable esophageal carcinoma after neoadjuvant therapy.

Lipoid Pneumonia: Spectrum of Clinical and Radiologic Manifestations

OBJECTIVE Lipoid pneumonia results from accumulation of lipids in the alveoli and can be either exogenous or endogenous in cause based on the source of the lipid. Exogenous lipoid pneumonia is caused by inhalation or aspiration of animal fat or vegetable or mineral oil. Endogenous lipoid pneumonia is usually associated with bronchial obstruction. The purpose of this article is to review the pathogenesis and clinical and radiologic manifestations of exogenous and endogenous lipoid pneumonia. CONCLUSION The ability to recognize the radiologic manifestations of lipoid pneumonia is important because, in the appropriate clinical setting, these findings can be diagnostic.

Preoperative Chemo-Radiation-Induced Ulceration in Patients with Esophageal Cancer: A Confounding Factor in Tumor Response Assessment in Integrated Computed Tomographic-Positron Emission Tomographic Imaging

Hypothesis: Positron emission tomography can be useful in predicting response of esophageal cancer after preoperative chemo-radiation therapy (CRT). We evaluated the use of integrated computed tomography (CT)-PET among patients with esophageal cancer being considered for resection after CRT. Methods: Three reviewers blinded to clinical and pathologic staging retrospectively reviewed the CT-PET scans of patients with esophageal cancer after preoperative CRT who underwent esophagectomy. [18F]-fluoro-2-deoxy-D-glucose uptake for residual malignancy was determined by visual analysis and semi-quantitatively when standardized uptake value (SUV) was ≥4. Results: Forty-two patients underwent esophageal resection. Using visual analysis, CT-PET had a sensitivity of 47% and specificity of 58% in detecting residual malignancy. Using semi-quantitative analysis, 19 patients had a SUV ≥4 in the region of the primary esophageal tumor and were interpreted as having residual malignancy (sensitivity 43%, specificity 50%). Of these 19, six had complete pathologic response to CRT. These false-positive results, due to therapy-induced ulceration detected at endoscopy, limit the use of CT-PET alone in detecting residual malignancy. Similarly, sensitivity (25%) and specificity (73%) of endoscopy/biopsy in detecting residual malignancy were poor. However, the accuracy of CT-PET in detecting residual malignancy was improved when combined with endoscopic findings. In the absence of ulceration at endoscopy, 8 of 8 patients with SUV ≥4 after chemo-radiation had residual malignancy at surgery. Conclusions: CRT-induced ulceration results in false-positive results on CT-PET and precludes accurate detection of residual esophageal tumor. However, CT-PET in combination with endoscopy is useful in identifying patients with a high risk of residual tumor post-CRT.

Imaging of non-small cell lung cancer of the superior sulcus: part 2: initial staging and assessment of resectability and therapeutic response.

Imaging plays a crucial role in the diagnosis and staging of superior sulcus tumors, assessment of their resectability, determination of the optimal approach to disease management, and evaluation of the response to therapy. Computed tomography (CT), magnetic resonance (MR) imaging, and positron emission tomography (PET)/CT contribute important and complementary information. Whereas CT is optimal for depicting bone erosion and for staging of intrathoracic disease, MR imaging is superior for evaluating tumor extension to the intervertebral neural foramina, the spinal cord, and the brachial plexus, primarily because of the higher contrast resolution and multiplanar capability available with MR imaging technology. Use of PET/CT enables the detection of unsuspected nodal and distant metastases. However, imaging has only limited usefulness for evaluating the response of a tumor to induction therapy and detecting local recurrence, and surgical biopsy often is necessary to verify the results of therapy.

Preoperative evaluation of patients with malignant pleural mesothelioma: role of integrated CT-PET imaging.

Malignant pleural mesothelioma (MPM) is an uncommon neoplasm arising from mesothelial cells of the pleura. The prognosis is poor with a median survival of 8 to 18 months after diagnosis. Multimodality regimens combining chemotherapy, radiotherapy, immunotherapy, and surgery are being used more frequently in patient management. Extrapleural pneumonectomy is the surgical treatment of choice in 10% to 15% of patients who present with resectable disease and is reported to prolong survival. Accurate staging is important to distinguish patients who are resectable from those requiring palliative therapy. Integrated computed tomography-positron emission tomography (CT-PET) increases the accuracy of overall staging in patients with MPM and significantly improves the selection of patients for curative surgical resection. Specifically, CT-PET detects more extensive disease involvement than that shown by other imaging modalities and is particularly useful in identifying occult distant metastases. This article reviews aspects of imaging performed in the initial staging of patients with MPM according to the International Mesothelioma Interest Group staging system and will emphasize the appropriate role of CT-PET imaging in determining the T, N, and M descriptors.

Opportunistic fungal pneumonia

Opportunistic fungal infection is a common cause of serious morbidity and mortality in immunocompromised patients. These infections occur primarily in patients with chemotherapy-induced neutropenia, acquired immunodeficiency syndrome. or immunosuppression after solid organ or bone marrow transplantation. The most important opportunistic fungal pathogens include Cryptococcus neoformans, Candida and Aspergillus species, and the fungi that cause mucormycosis. Opportunistic pneumonia caused by previously unrecognized pathogens, such as Fusarium, Penicillium, and the dematiaceous fungi, are increasingly reported. The clinical and radiologic features of opportunistic fungal pneumonia are highly variable and often nonspecific. Diagnosis requires knowledge of the various modes of presentation, radiologic manifestations, and epidemiology of these infections. Because many of these organisms can colonize the upper airway, sputum cultures are considered diagnostically unreliable. Instead, definitive diagnosis requires culture of the fungus from infected tissue or demonstration of the organism on microscopic examination.

Positron Emission Tomography/computed Tomography in Lung Cancer Staging, Prognosis, and Assessment of Therapeutic Response

Positron emission tomography (PET)/computed tomographic scanning, using 18F-2-deoxy-D-glucose, complements conventional imaging evaluation of patients with lung cancer. The strength of PET scanning lies in the detection of nodal and extrathoracic metastases. PET scanning is also currently being studied in the assessment of prognosis and therapeutic response and has the potential to alter management of oncologic patients. This review will discuss the role of PET/computed tomographic scanning in the diagnosis, staging, and evaluation of prognosis and treatment response in patients with lung cancer.

Esophageal cancer: the role of integrated CT-PET in initial staging and response assessment after preoperative therapy.

Esophageal cancer, an uncommon neoplasm, has been increasing in incidence over the past few decades. Optimal management of patients is determined by the stage of disease at presentation, patient performance status, and location of the primary cancer. Recently, there has been increasing use of multimodality therapy in suitable candidates that employs preoperative chemotherapy and/or radiation followed by surgical resection. This evolving treatment strategy together with the substantial morbidity and mortality associated with esophagectomy makes appropriate patient selection critical. Computed tomography (CT) and endoscopy/endoscopic ultrasonography are usually carried out to initially stage patients with esophageal cancer, to determine primary tumor response, and to detect nodal and distant metastases after preoperative therapy. Positron emission tomography (PET) with [18F]-fluoro-2-deoxy-D-glucose and integrated CT-PET are useful in the initial staging of patients with esophageal cancer and in the prediction of pathologic response, disease-free interval, and overall survival after preoperative therapy. Importantly, integrated CT-PET imaging decreases the number of futile attempts at surgical resection, mainly because of the detection of occult distant metastases. The following sections review the use of integrated CT-PET imaging in determining the T, N, and M descriptors of the American Joint Commission on Cancers 2002 guidelines for pathologic and clinical staging at initial diagnosis and after chemoradiation therapy in those patients being considered for surgical resection.