Accuracy of four-dimensional CT for the localization of abnormal parathyroid glands in patients with primary hyperparathyroidism.

PURPOSE: To investigate multiphase multidetector four-dimensional computed tomography (CT) as a technique to correctly localize abnormal parathyroid glands in patients with primary hyperparathyroidism. MATERIALS AND METHODS: Informed consent was waived by the institutional review body for this retrospective, chart review study. Radiology reports from four-dimensional CT and surgical notes were reviewed in 143 patients with primary hyperparathyroidism (35 men, 108 women; median ages, 58 and 60 years, respectively) who underwent parathyroid surgery between August 2004 and January 2007 and in whom four-dimensional CT predicted a single lesion. Accuracy of four-dimensional CT was stratified by patient and was determined separately for localization to the correct side and quadrant (upper and lower for each side), with surgical findings serving as standard of reference. RESULTS: In 143 patients, 148 abnormal parathyroid glands were found at surgery; 137 (93%) of these were weighed, with mean and median weights of 757 and 417 mg, respectively. Four-dimensional CT lateralized the abnormal glands with 93.7% accuracy (134 of 143). For localization according to quadrant, the accuracy was 86.6% (116 of 134). CONCLUSION: Four-dimensional CT has sufficiently high accuracy in presurgical localization to allow confident performance of unilateral parathyroidectomy in patients with sporadic primary hyperparathyroidism. The superior accuracy compared with that of ultrasonography and technetium 99m sestamibi scanning may be sufficient to allow four-dimensional CT to be used as the sole presurgical localization method.

Imaging characteristics of hyperfunctioning parathyroid adenomas using multiphase multidectector computed tomography: a quantitative and qualitative approach.

OBJECTIVE: The objective of the study was to characterize the enhancement pattern of hyperfunctioning parathyroid adenomas on multiphase multidetector computed tomography (CT) or 4-dimensional CT. METHODS: We retrospectively studied the enhancement patterns of 48 pathologically confirmed parathyroid adenomas with 4-dimensional CT, compliant with institutional review and the Health Insurance Portability and Accountability Act. Region-of-interest analysis was done at baseline and at arterial (25 seconds), venous (55 seconds), and delayed (85 seconds) enhancement phases over the adenoma and adjacent normal thyroid tissue. Qualitative and quantitative analysis was done. Discriminant functions were calculated using a multivariate logistic regression model, and receiver operating characteristic curves were measured. RESULTS: Adenomas are lower than thyroid in density, demonstrate avid early contrast enhancement, and show rapid wash-out of contrast. Adenomas and thyroid had baseline Hounsfield unit attenuations of 35 ± 11 and 94 ± 21 and enhancement percentage change from baseline to arterial of 493% ± 328% and 132% ± 148%, respectively (P < 0.0001 both). Quantitative analysis showed that these 2 measures of baseline density and the percentage change from baseline to arterial were the most powerful discriminatory features, with contrast wash-out from arterial peak to venous phase being a less powerful discriminator. Several discriminant functions were derived, the best of which was: X = 13.74 - (0.207 × baseline Hounsfield unit) - (0.006 × percent density change from baseline to arterial). X > 0.2 classifies tissue as parathyroid with high certainty (area under the receiver operating characteristic curve = 0.98; specificity, 0.938; sensitivity, 0.999). CONCLUSIONS: Parathyroid adenomas have a characteristic enhancement pattern that can be distinguished from thyroid tissue: the key diagnostic discriminators are baseline density, percentage change in density from baseline to arterial enhancement, and percentage decrease in density from arterial to venous phases.

Purulent chondritis of thyroid cartilage.

We report a case of a 77-year-old female with purulent chondritis of the thyroid cartilage who was initially referred for laryngeal neoplasm. Purulent chondritis of the laryngeal cartilage is a rare entity with three reports in the literature. The unique CT imaging features of expansile laryngeal cartilage with peripheral rim enhancement and central fluid-attenuation correlate to the abscess formation between the inner and outer perichondria. The correct imaging assessment prompts surgical management and avoid misdiagnosis.

Radiation Therapy as an Effective Salvage Strategy for Secondary CNS Lymphoma.

PURPOSE: We assessed the efficacy of radiation therapy (RT) in the management of secondary central nervous system (CNS) lymphoma. METHODS AND MATERIALS: The cohort comprised 44 patients with systemic diffuse large B-cell lymphoma (DLBCL) secondarily involving the brain and/or leptomeninges at initial diagnosis or relapse that was treated with RT. RESULTS: Of these patients, 29 (66%) were in systemic remission when CNS disease was diagnosed. The overall response rate to RT by magnetic resonance imaging was 88% (42% complete, 46% partial). The median overall survival (OS) after RT initiation was 7 months (95% confidence interval 4-10 months). The OS curve plateaued at 31% from 2 to 8 years. OS was superior in patients who achieved a complete or partial response to RT, underwent stem cell transplantation after RT, and had brain parenchymal (vs leptomeningeal) disease. Eight cases of CNS disease progression occurred after RT: 1 involved the brain parenchyma, and 7 involved the spine and/or cerebrospinal fluid and/or meninges. CONCLUSIONS: We conclude that RT is associated with high response rates and may contribute to long-term OS. In addition, RT may provide CNS disease control that facilitates successful salvage with stem cell transplantation in patients with chemotherapy-refractory disease.

Waiting to exhale: salvaging the nondiagnostic CT pulmonary angiogram by using expiratory imaging to improve contrast dynamics.

We attempted to investigate whether computed tomography pulmonary angiography (CTPA) in the expiratory phase can improve contrast enhancement of the pulmonary arteries and mitigate the effect of inspiratory transient attenuation artifact, potentially salvaging nondiagnostic studies. Eighteen patients with indeterminate inspiratory CTPA, despite proper contrast bolus were studied. Patients were rescanned in expiration using the same contrast bolus and scanning parameters. The attenuation of each pulmonary arterial segment, superior and inferior vena cava, and atria and ventricles during the two phases of respiration was measured independently by three radiologists. All pulmonary segments were evaluated for filling defects during the two phases. In addition, the studies were graded for diagnostic quality of enhancement and probable impact on management. A statistically significant increase in pulmonary arterial enhancement was seen during expiration from the pulmonary trunk to the segmental pulmonary arteries (P < 0.001) and for the inferior vena cava, the right atrium, and the ventricle. The incidence of nondiagnostic inspiratory studies ranged from 89 to 100%, depending on the observer. All studies were upgraded to fully acceptable diagnostic quality with follow-up expiratory imaging (P < 0.0001). Expiratory phase imaging was observed to have diagnostic impact in 78 to 88% of cases, with overall good to moderate interobserver agreement. In one case, pulmonary embolism was detected on the expiratory scan, which was not seen on the inspiratory scan. Expiratory imaging for nondiagnostic CTPA improves pulmonary arterial enhancement and improves diagnostic quality of CTPA by eliminating transient attenuation artifact, thus facilitating more accurate diagnosis and providing earlier treatment of pulmonary embolism.