Adrenal mass evaluation in patients with lung carcinoma: a cost-effectiveness analysis

Two nomograms based on radiomics models using triphasic CT for differentiation of adrenal lipid-poor benign lesions and metastases in a cancer population: an exploratory study

OBJECTIVES

To investigate the effectiveness of CT-based radiomics nomograms in differentiating adrenal lipid-poor benign lesions and metastases in a cancer population.

METHODS

This retrospective study enrolled 178 patients with cancer history from three medical centres categorised as those with adrenal lipid-poor benign lesions or metastases. Patients were divided into training, validation, and external testing cohorts. Radiomics features were extracted from triphasic CT images (unenhanced, arterial, and venous) to establish three single-phase models and one triphasic radiomics model using logistic regression. Unenhanced and triphasic nomograms were established by incorporating significant clinico-radiological factors and radscores. The models were evaluated by the receiver operating characteristic curve, Delong's test, calibration curve, and decision curve.

RESULTS

Lesion side, diameter, and enhancement ratio resulted as independent factors and were selected into nomograms. The areas under the curves (AUCs) of unenhanced and triphasic radiomics models in validation (0.878, 0.914, p = 0.381) and external testing cohorts (0.900, 0.893, p = 0.882) were similar and higher than arterial and venous models (validation: 0.842, 0.765; testing: 0.814, 0.806). Unenhanced and triphasic nomograms yielded similar AUCs in validation (0.903, 0.906, p = 0.955) and testing cohorts (0.928, 0.946, p = 0.528). The calibration curves showed good agreement and decision curves indicated satisfactory clinical benefits.

CONCLUSION

Unenhanced and triphasic CT-based radiomics nomograms resulted as a useful tool to differentiate adrenal lipid-poor benign lesions from metastases in a cancer population. They exhibited similar predictive efficacies, indicating that enhanced examinations could be avoided in special populations.

KEY POINTS

• All four radiomics models and two nomograms using triphasic CT images exhibited favourable performances in three cohorts to characterise the cancer population's adrenal benign lesions and metastases. • Unenhanced and triphasic radiomics models had similar predictive performances, outperforming arterial and venous models. • Unenhanced and triphasic nomograms also exhibited similar efficacies and good clinical benefits, indicating that contrast-enhanced examinations could be avoided when identifying adrenal benign lesions and metastases.

Hyperattenuating adrenal lesions in lung cancer: biphasic CT with unenhanced and 1-min enhanced images reliably predicts benign lesions

OBJECTIVES

To investigate usefulness of biphasic computed tomography (CT) in characterizing hyperattenuating adrenal lesions in lung cancer.

METHODS

This retrospective study included 239 patients with lung cancer who underwent adrenal CT for hyperattenuating (> 10 Hounsfield unit) adrenal lesions. Adrenal CT comprised unenhanced and 1-min and 15-min enhanced images. We dichotomized adrenal lesions depending on benign or metastatic lesions. Reference standard for benignity was histologic confirmation or ≥ 6-month stability on follow-up CT. Two independent readers analyzed absolute (APW) or relative percentage wash-out (RPW) using triphasic CT, and enhancement ratio (ER) or percentage wash-in (PWI) using biphasic CT (i.e., unenhanced and 1-min enhanced CT). Criteria for benignity were as follows: criteria 1, (a) APW ≥ 60% or (b) RPW ≥ 40%, and criteria 2, (a) ER > 3 and (b) PWI > 200%. We analyzed area under the curve (AUC) and accuracy for benignity, and inter-reader agreement.

RESULTS

Proportion of benign adrenal lesion was 71.1% (170/239). For criteria 1 and 2, AUCs were 0.872 (95% confidence interval [CI], 0.822-0.911) and 0.886 (95% CI, 0.838-0.923), respectively, for reader 1 (p = 0.566) and 0.816 (95% CI, 0.761-0.863) and 0.814 (95% CI, 0.759-0.862), respectively, for reader 2 (p = 0.955), and accuracies were 87.9% (210/239) and 86.2% (206/239), respectively, for reader 1 (p = 0.479) and 81.2% (194/239) and 80.3% (192/239), respectively, for reader 2 (p = 0.763). Weighted kappa was 0.725 (95% CI, 0.634-0.816) for criteria 1 and 0.736 (95% CI, 0.649-0.824) for criteria 2.

CONCLUSION

Biphasic CT can reliably characterize hyperattenuating adrenal lesions in patients with lung cancer.

KEY POINTS

• Criteria from biphasic computed tomography (CT) for diagnosing benign adrenal lesions were enhancement ratio of > 3 and percentage wash-in of > 200%. • In the analysis by two independent readers, area under the curve between criteria 1 and 2 was not significantly different (0.872 and 0.886 for reader 1; 0.816 and 0.814, for reader 2; p > 0.05 for each comparison). • Wash-in characteristics from biphasic CT are helpful to predict benign adrenal lesions in lung cancer.

PET, CT, and MR Imaging for Assessment of Thoracic Malignancy: Structure Meets Function

Imaging of patients with thoracic malignancy usually requires a multimodality approach. Each of these modalities has its own strengths and weaknesses. CT remains central to the staging and restaging of thoracic malignancies, but has recently been complemented with [18F]-2-fluoro-2-deoxy-D-glucose(FDG)-positron emission tomography (PET) imaging to maximize its potential. Furthermore, because FDG-PET/CT is useful at all stages of the workup and treatment of these patients, this modality has taken hold in the clinical realm for evaluation of patients with thoracic malignancy and is rapidly replacing PET-only imaging. MR imaging is also occasionally used in some patients with thoracic malignancies to improve disease staging or lesion characterization. PET/MR imaging may come to be used to evaluate patients with thoracic malignancies as well.

Non-small cell lung cancer: whole-body MR examination for M-stage assessment--utility for whole-body diffusion-weighted imaging compared with integrated FDG PET/CT

PURPOSE

To prospectively and directly compare the capability of whole-body diffusion-weighted (DW) imaging, whole-body magnetic resonance (MR) imaging with and that without DW imaging, and integrated fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) for M-stage assessment in non-small cell lung cancer (NSCLC) patients.

MATERIALS AND METHODS

The institutional review board approved this study; informed consent was obtained from patients. A total of 203 NSCLC patients (109 men, 94 women; mean age, 72 years) prospectively underwent whole-body DW imaging, whole-body MR imaging, and FDG PET/CT. Final diagnosis of the M-stage in each patient was determined on the basis of results of all radiologic and follow-up examinations. Two chest radiologists and two nuclear medicine physicians independently assessed all examination results and used a five-point visual scoring system to evaluate the probability of metastases. Final diagnosis based on each of the methods was made by consensus of two readers. Receiver operating characteristic (ROC) analysis was used to compare the capability for M-stage assessment among whole-body DW imaging, whole-body MR imaging with and that without DW imaging, and PET/CT on a per-patient basis. Sensitivity, specificity, and accuracy were compared with the McNemar test.

RESULTS

Area under ROC curve (A(z)) values of whole-body MR imaging with DW imaging (A(z) = 0.87, P = .04) and integrated FDG PET/CT (A(z) = 0.89, P = .02) were significantly larger than that of whole-body DW imaging (A(z) = 0.79). Specificity and accuracy of whole-body MR imaging with (specificity, P = .02; accuracy, P < .01) and that without DW imaging (specificity, P = .02; accuracy, P = .01) and integrated FDG PET/CT (specificity, P < .01; accuracy, P < .01) were significantly higher than those of whole-body DW imaging.

CONCLUSION

Whole-body MR imaging with DW imaging can be used for M-stage assessment in NSCLC patients with accuracy as good as that of PET/CT.

CT, positron emission tomography, and MRI in staging lung cancer

Lung cancer is a common malignancy and remains the leading cause of cancer-related deaths in both men and women in the United States. Imaging plays an important role in the detection, diagnosis, and staging of the disease as well as in assessing response to therapy and monitoring for tumor recurrence after treatment. This article reviews the staging of the two major histologic categories of lung cancer-non-small-cell lung carcinoma (NSCLC) and small-cell lung carcinoma-and emphasizes the appropriate use of CT, MRI, and positron emission tomography imaging in patient management. Also discussed are proposed revisions of the International Association for the Study of Lung Cancer's terms used to describe the extent of NSCLC in terms of the primary tumor, lymph nodes, and metastases descriptors.

Imaging to optimally stage lung cancer: conventional modalities and PET/CT

Accurately staging patients with lung cancer is important in determining treatment options and prognoses. Staging allows the distinction of patients who are candidates for surgical resection from those with inoperable disease who may be treated with chemotherapy and/or radiation therapy. Conventional imaging plays an essential role in the noninvasive and invasive methods of the evaluation and staging of patients with non-small-cell lung cancer (NSCLC). Imaging modalities used for staging include chest radiography, chest computed tomography (CT), abdominal CT, brain CT or magnetic resonance imaging, bone scans, and (18)F-2-deoxy-d-glucose positron emission tomography (PET). Recently, PET/CT, the integration of the functional data of PET with the anatomic data of CT, has emerged as a modality to potentially change the way patients are evaluated. This article reviews current recommendations regarding the staging of patients with NSCLC and addresses the role of PET/CT.

Positron emission tomography imaging in nonsmall-cell lung cancer

Positron emission tomography (PET) using 18F-2-deoxy-D-glucose, a D-glucose analog labeled with fluorine-18, complements conventional radiologic assessment in the evaluation of patients with nonsmall-cell lung cancer (NSCLC). PET is being routinely used to improve the detection of nodal and extrathoracic metastases. PET is also currently being evaluated in the assessment of prognosis and therapeutic response and by potentially allowing an earlier assessment of response may prove invaluable in the oncologic management of patients. The article discusses the diagnosis, staging, and assessment of treatment response and prognosis with an emphasis on the appropriate clinical use of PET in management.

Whole-body MR imaging vs. FDG-PET: Comparison of accuracy of M-stage diagnosis for lung cancer patients

PURPOSE

To conduct a prospective comparison of the accuracy of whole-body MR imaging and positron emission tomography (PET) with fluorine-18 deoxyglucose (FDG) (FDG-PET) to assess the M-stage in lung cancer patients.

MATERIALS AND METHODS

A total of 90 consecutive lung cancer patients (mean age = 68 years) underwent whole-body MR imaging and FDG-PET as well as other standard radiological imaging procedures before and after treatment. Probabilities of metastases on whole-body MR imaging and FDG-PET were assessed by using 5-point scoring systems on a per-site basis and on a per-patient basis. Receiver operating characteristic (ROC) curve analysis was used to compare diagnostic capabilities. Sensitivity, specificity, and accuracy were also compared by using the McNemar's test on a per-site and per-patient basis.

RESULTS

For assessment of head and neck metastases and bone metastases, accuracies of whole-body MR imaging (95.0% and 94.8%, respectively) were significantly higher than those of FDG-PET (89.1% and 88.2%, respectively; P < 0.05). For assessment of the M-stage on a per-patient basis, accuracy of whole-body MR imaging (80.0%) was also significantly higher than that of FDG-PET (73.3%; P < 0.05).

CONCLUSION

Whole-body MR imaging is an accurate diagnostic technique and may be considered at least as effective as FDG-PET for assessment of the M-stage of lung cancer patients.

Integrated PET-CT for the characterization of adrenal gland lesions in cancer patients: diagnostic efficacy and interpretation pitfalls

Integrated fluorine-18 fluorodeoxyglucose positron emission tomography (PET)-computed tomography (CT) for adrenal gland imaging in cancer patients allows early detection and accurate localization of adrenal lesions and differentiation of metastatic nodules from benign lesions, thereby facilitating treatment planning. However, false-positive findings are encountered at integrated PET-CT in approximately 5% of adrenal lesions identified as positive at PET, including adrenal adenomas, adrenal endothelial cysts, and inflammatory and infectious lesions. Moreover, false-negative findings may be seen in adrenal metastatic lesions with hemorrhage or necrosis, small-sized (<10-mm) metastatic nodules, and metastases from pulmonary bronchioloalveolar carcinoma or carcinoid tumors. An awareness of the potential pitfalls of integrated PET-CT enhances the diagnostic efficacy of this modality by allowing differentiation of metastatic adrenal lesions from other abnormalities.

Chemical shift MR imaging of hyperattenuating (>10 HU) adrenal masses: does it still have a role?

PURPOSE

To evaluate chemical shift magnetic resonance (MR) imaging for the characterization of hyperattenuating adrenal masses.

MATERIALS AND METHODS

Adrenal MR images obtained from January 1998 to February 2003 were reviewed. Patients were excluded if they did not undergo unenhanced computed tomography or did not have an adrenal mass with attenuation higher than 10 HU, adequate follow-up, or pathologic diagnosis for use as a reference standard. A diagnosis of adenoma required at least 24 weeks of stability on images. Thirty-eight masses in 36 patients were identified (27 adenomas, nine metastases, one adrenocortical oncocytoma, and one pheochromocytoma). Signal intensity (SI) decrease between in-phase and opposed-phase MR images was measured for the entire mass and normalized to the renal parenchymal SI. In 21 of 36 (58%) patients, dual-echo single-breath-hold MR imaging was used to eliminate misregistration.

RESULTS

The attenuation of 61% (23 of 38) of all masses and 70% (19 of 27) of adenomas was 10-30 HU. With a threshold of 20% SI decrease, the sensitivity of chemical shift MR imaging for hyperattenuating adenoma was 67% (18 of 27 masses). When considering masses with attenuation of 10-30 HU, the sensitivity for adenoma was 89% (17 of 19 masses) and remained reasonable at 75% (six of eight masses) for adenomas with attenuation of 20-30 HU. Only one adenoma with attenuation higher than 30 HU had SI decrease of more than 20%. Specificity for diagnosis of adenoma was 100% (11 of 11).

CONCLUSION

In certain circumstances, chemical shift MR imaging is a reasonable second imaging test for further characterization of a hyperattenuating adrenal mass.

Lung cancer--where are we today? Current advances in staging and nonsurgical treatment

Lung cancer remains the commonest cause of cancer death in both men and women in the developed world, although mortality rates for men are dropping. Spiral computed tomography (CT) of the chest in middle-aged, smoking subjects may identify two to four times more lung cancers than a chest X-ray, with more than 70% of tumors being Stage I. The incidence of benign nodules is high, making interpretation difficult. Randomized controlled trials are required to determine whether spiral CT detects lung cancer early enough to improve mortality. Preoperative staging has relied on CT scans, but positron emission tomography scanning has greater sensitivity, specificity, and accuracy than CT and is recommended as the final confirmatory investigation when the CT shows resectable disease. In locally advanced non-small cell lung cancer, there is a small advantage for the addition of chemotherapy to radiotherapy, but no advantage for postoperative radiotherapy. Chemotherapy gives no benefit when given as neoadjuvant or adjuvant treatment around surgery. In advanced disease, newer cytotoxic agents confer a small survival advantage over older combinations, but the advantage in median survival over best supportive care remains a few months with modest improvements in quality of life. Survival with small cell lung cancer has shown little increase over the last 15 years despite multiple attempts to manipulate the timing, dose intensity of chemotherapy, and the potential of radiotherapy. Novel therapies are urgently needed for all cell types of lung cancer.

Positron emission tomography in lung cancer

Carcinoma of the lung is one of the most frequent malignancies and a major cause of mortality. The use of positron emission tomography (PET) has been extensively investigated in patients with carcinoma of the lung and has established clinical utility and cost-effectiveness in characterization of solitary pulmonary nodules and preoperative staging of carcinoma of the lung. Evolving applications in carcinoma of the lung include detection of recurrence, assessment of treatment response, radiotherapy planning, and prognosis. In addition, there is developing interest in combined anatomic/metabolic imaging and new tracer techniques, in particular gene expression imaging. This review aims to present existing data supporting the use of PET in carcinoma of the lung and to explore the evolving indications and future prospects of PET and lung cancer.

Cost analysis model: US versus endometrial biopsy in evaluation of peri- and postmenopausal abnormal vaginal bleeding

PURPOSE

To develop a cost minimization analysis model from the societal perspective of Medicare reimbursement to determine whether endometrial biopsy or transvaginal ultrasonography (US) is less expensive in evaluating peri- and postmenopausal women with abnormal vaginal bleeding and to assess whether this strategy is equally effective in populations at low and high risk for endometrial carcinoma.

MATERIALS AND METHODS

Clinical algorithms were constructed that detailed diagnostic evaluation of the target population by using office-based endometrial biopsy versus transvaginal US as starting points. An economic model based on Medicare reimbursement and average wholesale drug price data and using disease prevalences and modality sensitivities from the scientific literature was then created to examine common bleeding causes in this population. All models included the cost of obtaining a tissue diagnosis for focal or diffuse endometrial thickening found at US. Modality sensitivities and prevalences of disease states were varied within the model to discover limits at which each modality became cheaper versus the other for assessing a population of women.

RESULTS

Population prevalence of neoplastic disease is the principal factor governing total cost between competing diagnostic algorithms. In populations with 31% or less combined prevalence of endometrial carcinoma/atypical adenomatous hyperplasia, algorithms utilizing transvaginal US as the initial test are most cost minimizing. At combined endometrial carcinoma/atypical adenomatous hyperplasia prevalence of 10%, savings of up to 11% and 16% over pathways initiated with endometrial biopsy are predicted. In populations with a high incidence of neoplastic disease (>31%), biopsy-based algorithms should become least costly.

CONCLUSION

Transvaginal US-initiated triage predicts substantial cost savings versus biopsy-based algorithms in evaluating typical populations of peri- and postmenopausal women with abnormal vaginal bleeding seen in clinical practice.