Akitoshi Saito

High-Resolution CT Features: Prognostic Significance in Peripheral Lung Adenocarcinoma with Bronchioloalveolar Carcinoma Components

Background: Based on Noguchi’s classification, adenocarcinomas with bronchioloalveolar carcinoma (BAC) components have a heterogeneous prognosis. However, until now, the prognostic factors in this tumor category have not been clarified. Objectives: We studied the prognostic significance of high-resolution CT (HRCT) findings in this tumor subtype. Materials and Methods: HRCT findings [lesion size, percentage of ground-glass opacity (GGO) areas in the lesion, presence or absence of lobulation, coarse spiculation, pleural tag, satellite lesion, air bronchogram, and site of the lesion], clinical data (age, gender and surgical method), and pathologic findings (degree of tumor differentiation and presence or absence of nodal metastasis) were analyzed in 52 consecutive patients with adenocarcinoma with BAC components <3 cm (mean, 1.7 cm). The patients included 32 women and 20 men with a mean age of 66 years. The results correlated with survival using univariate and multivariate analysis. The mean follow-up period was 41 months. Results: Nine (17%) of the 52 patients died of lung cancer. In univariate analysis, a significant difference was found for lobulation (p = 0.018), %GGO (p = 0.043), air bronchogram (p = 0.003), site of lesion (p = 0.034), degree of tumor differentiation (p = 0.001), and nodal metastasis (p = 0.040). Multivariate analysis using the 6 factors that were significant in univariate analysis as independent variables revealed that an air bronchogram (p = 0.010) and the degree of tumor differentiation (p = 0.008) were significant independent factors for survival. Conclusion: The presence of an air bronchogram on HRCT may have an independent prognostic significance in lung adenocarcinoma with BAC components.

Spontaneous extensive necrosis in non-Hodgkin lymphoma : Prevalence and clinical significance

Purpose We studied the prevalence of spontaneous extensive necrosis in the nodes of patients with non-Hodgkin lymphomas and assessed the clinical significance of this finding. Method CT and MRI performed before initiation of radiation or chemotherapy were reviewed in 60 consecutive patients with non-Hodgkin lymphomas to evaluate the presence or absence of spontaneous extensive necrosis in the lymphomatous nodes. The results were correlated with histopathologic grading, stages of lymphomas, maximal axial diameters of the lesions, International Prognostic Index (IPI), age, and serum lactate dehydrogenase (LDH) levels. We then performed Kaplan-Meier analysis of disease-free survival using each factor. Results Extensive necrotic nodes that appeared as rim-enhanced masses on enhanced CT or MR images were found in 15 patients (25%), of whom 10 patients had pathologic verification. The patients with necrosis had significantly higher stages (Stage II or higher), greater IPI (IPI of ≥2), and higher serum LDH levels than those without necrosis (p = 0.001, p = 0.005, and p = 0.005, respectively). With the Kaplan-Meier method, a statistically significant difference was noted for serum LDH levels (p = 0.015) and IPI (p = 0.021) but not for extensive necrosis (p = 0.600). Conclusion Spontaneous extensive necrosis in lymphomatous nodes is not a rare event. This finding may have a prognostic significance for patients with non-Hodgkin lymphomas.

Radiologic assessment of metastases to the thyroid gland.

Purpose We reviewed the radiologic and clinical data in patients with metastatic disease to the thyroid gland and assessed the role of radiologic techniques in this disorder. Method The findings on US (n = 11), CT (n = 7), MRI (n = 6), palpation or US-guided fine needle aspiration (FNA) biopsy, and clinical records were reviewed in 11 cases of pathologically verified metastatic tumors of the thyroid gland. Results Five patients had palpable thyroid nodules and six had nonpalpable nodules discovered incidentally with imaging procedures. Three patients had no known malignancies at the time of diagnosis of thyroid tumors. Correct diagnosis was obtained in 10 of the 11 cases with FNA biopsy. Thyroid metastases were detected in all of the cases with US and MRI and six of the seven cases with CT. Thyroid metastases were solitary (n = 5) or multiple (n = 6), and about half of them measured <2 cm in diameter. These tumors typically had well defined margins and no calcification and sometimes had cystic portions. Multiple nodules within the same patient were radiologically quite similar to each other. On US, metastases appeared as hypoechoic or markedly hypoechoic areas without halo, on CT as low density areas, and on MRI as areas of varying signal intensities. Half of the metastases showed hypointensity on either T2-weighted images or gadolinium-enhanced T1-weighted images. The tumors involved lymph nodes in 10 cases and other remote organs in 5. Level I or II or parotid nodes were involved in six cases. Conclusion These radiologic features may alert clinicians to a possibility of metastatic thyroid cancer. US combined with US-guided FNA biopsy is suitable for early diagnosis of metastases to the thyroid gland.

Differentiated thyroid carcinomas. Prediction of tumor invasion with MR imaging.

Purpose: To assess diagnostic accuracy for tumor invasion of surrounding organs by measurement of tumor circumferences on MR images in patients with differentiated thyroid carcinomas. Material and Methods: Surgical and MR imaging findings in 50 patients with differentiated thyroid carcinoma (43 primary, 7 recurrent lesions) were retrospectively reviewed. The degrees of circumference of tumor encroachment to the organs were measured, and the measurements and morphologic diagnosis of tumor invasion made by a head and neck radiologist were compared with surgical and pathologic findings using receiver operating characteristic curves. Results: Diagnosis of tumor invasion by the radiologist was superior to the measurements of the carotid artery and cartilage, while the reverse was true for the trachea and esophagus. However, no statistical differences were noted between them for each structure. Optimal thresholds for tumor invasion were 90° or more for the cartilage (94% accuracy) and esophagus (86% accuracy), 135° or more for the trachea (86% accuracy), and 225° or more for the carotid artery (90% accuracy). Conclusion: Tumor invasion was more accurately diagnosed by measurement of tumor circumferences of each organ on MR images.

Head and neck lesions: determination of an optimal MT technique for prediction of malignancies.

RATIONALE AND OBJECTIVES To determine an optimal magnetization transfer (MT) technique for diagnosis of malignancies in the head and neck. METHODS Lesion magnetization transfer ratios (MTRs) and lesion-to-muscle MTRs were prospectively measured in 52 head and neck lesions of 52 patients at frequency offsets of 0.3, 0.5, and 1 kHz from water resonance. The diagnostic capability for each MT pulse was calculated by using receiver operating characteristic (ROC) curves, and an optimal MT technique was determined for diagnosis of malignancies. RESULTS The lesion MTRs and the lesion-to-muscle MTRs in malignant tumors were statistically significantly greater than those in benign lesions at both 0.5- and 1-kHz MT pulses, but no significant differences were noted between them at the 0.3-kHz MT pulse. Diagnosis with the lesion-to-muscle MTRs was better than that with the lesion MTRs at each MT pulse. Among all MTRs, lesion-to-muscle MTRs at the 1-kHz MT pulse showed the highest diagnostic capability for malignancies (area under the ROC curve = 0.82+/-0.06). With a lesion-to-muscle MTR at a 1-kHz MT pulse of 0.61 or greater, the highest accuracy of 85% was attained with 90% sensitivity and 77% specificity. CONCLUSIONS Lesion-to-muscle MTRs at a 1-kHz MT pulse were optimal for diagnosis of malignancies in the head and neck.