Bronchogenic carcinoma: a survey of CT protocols for staging disease

Minimising the impact of errors in the interpretation of CT images for surveillance and evaluation of therapy in cancer

Radiological error is inevitable and usually multifactorial. Error can be secondary to radiologist-specific causes, including cognitive and perceptive errors or ambiguity of report, or system-related causes, including inadequate, misleading, or incorrect clinical information, poor imaging technique, excessive workload, and poor working conditions. In this paper, we discuss a systematic approach to reduce errors in oncological radiology reporting, thus reducing risk to the patient. Rather than attempt to discuss all types of error, we concentrate on the most important and commonly occurring errors that we have encountered over 20 years of practice, based on weekly discrepancy reviews of our practice and independent reviews of clinical and research imaging from other institutions. This review focuses on computed tomography (CT) reporting for staging, surveillance, and response assessment of cancer patients, but the messages apply to all imaging methods.

[Small-cell lung carcinoma: CT imaging features]

Small cell lung carcinoma (SCLC) typically is central in location. It is a very aggressive tumor characterized by its propensity for invasion of mediastinal structures, frequently, the ipsilateral pulmonary artery, multifocal nodal metastases and high frequency of distant metastases at initial presentation. CT is very sensitive and effective for local and regional staging. Combined with other diagnostic modalities, especially PET imaging, it allows whole body imaging for accurate staging, which is mandatory for therapeutic management. The different CT imaging features of SCLC and its more specific imaging characteristics will be reviewed in this article.

Non-small cell lung cancer: FDG PET for nodal staging in patients with stage I disease

PURPOSE

To determine the accuracy of 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) in the evaluation of regional lymph nodes in patients with stage I non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

Imaging and clinical findings obtained during 5 years in 84 patients (mean age, 66 years) were reviewed. Patients had thoracic computed tomographic findings of stage I NSCLC, an FDG PET study, and histopathologic proof of lung cancer. At the time of diagnosis, disease stage was assigned on the basis of FDG PET results and was compared with the histopathologic stage to determine the accuracy of PET.

RESULTS

When PET stage was compared with histopathologic stage, the disease in 72 (86%) patients was accurately staged with PET, understaged in two (2%), and overstaged in 10 (12%). The overall sensitivity, specificity, and positive and negative predictive values for PET of regional lymph nodal metastases were 82%, 86%, 47%, and 97%, respectively.

CONCLUSION

FDG PET enables accurate staging of regional lymph node disease in patients with stage I NSCLC. A negative PET scan in these patients suggests that mediastinoscopy is unnecessary and that these patients can proceed directly to thoracotomy.

Intravenous extension of lung carcinoma to the left atrium: demonstration by positron emission tomography with CT correlation

Intravenous extension of lung carcinoma is rare. A right upper lobe bronchogenic carcinoma with unusually elongated intravenous extension to the left atrium was first visualized with positron emission tomography (PET) and then confirmed with dynamic CT. The PET appearance of intravascular tumour spread is striking, and presents only a short differential diagnosis.

Positron emission tomography imaging in the thorax

Positron emission tomography imaging has proven valuable in the evaluation and management of thoracic abnormalities. It is more accurate than CT or MR imaging in characterizing indeterminate focal abnormal pulmonary opacities, staging lung cancer, and assessing the therapeutic response. PET imaging in lung cancer also appears to be cost-effective, particularly with whole-body studies. The metabolic and physiologic abnormalities used in FDG-PET imaging, rather than conventional anatomic or morphologic characteristics, provide an invaluable model for the future of tumor imaging.

Positron Emission Tomography Imaging in Lung Cancer

Over the past several years, positron emission tomography (PET) has become a clinically useful, noninvasive study which complements conventional imaging (chest radiographs, computed tomography [CT], and magnetic resonance imaging [MRI]) in the evaluation of patients with lung cancer. PET imaging of lung cancer is typically performed with the radiopharmaceutical 18F-2-deoxy-D-glucose (FDG), a d-glucose analog. Increased glucose metabolism by malignant cells results in increased uptake and accumulation of FDG, which serves as the basis for tumor detection. This review will focus on the current applications of FDG-PET in lung cancer patients including evaluation of focal pulmonary abnormalities, staging lung cancer, determining tumor recurrence, and in assessing prognosis.

Lung cancer staging and management: comparison of contrast-enhanced and nonenhanced helical CT of the thorax

PURPOSE

To determine whether contrast material-enhanced helical computed tomography (CT) of the thorax and upper abdomen changes the tumor stage and management compared with nonenhanced helical CT in patients with newly diagnosed lung cancer.

MATERIALS AND METHODS

During 15 months, any patient in whom lung cancer was strongly suspected or newly diagnosed and who was scheduled for thoracic CT was considered eligible for the study. All patients underwent nonenhanced thoracic helical CT from the lung apices through the adrenal glands and then contrast-enhanced thoracic helical CT from the lung apices through the entire liver. Each study was read independently, and the thoracic radiologic stage was determined. Tissue sampling was performed and the final pathologic stage assigned.

RESULTS

Ninety-six patients had a final pathologic diagnosis of lung cancer. There was agreement in stage between the nonenhanced and contrast-enhanced examinations in 92 of the 96 patients. In three patients, the tumor stage at nonehanced CT increased at contrast-enhanced CT, from IA to IIA (n = 1), IIB to IV (n = 1), and IIIB to IV (n = 1). In one patient, the tumor stage decreased from IIIB to IIB. There was no substantial change in management of any patient.

CONCLUSION

The results suggest that contrast-enhanced thoracic CT through the liver for staging lung cancer rarely changes the tumor stage determined with nonenhanced CT through the adrenal glands and does not substantially influence management decisions.