The sonographic features of follicular adenoma and follicular carcinoma are very similar, but larger lesion size, lack of a sonographic halo, hypoechoic appearance, and absence of cystic change favored a follicular carcinoma diagnosis. Increased patient age and male sex are associated with malignancy. Within the follicular carcinoma subgroup, Hürthle-cell variant of follicular carcinoma is more often seen in older patients with nodules having a heterogeneous appearance and lacking internal calcifications.

OBJECT Precise localization and understanding of the origin of spontaneous high-flow spinal CSF leaks is required prior to targeted treatment. This study demonstrates the utility of ultrafast dynamic CT myelography for the precise localization of high-flow CSF leaks caused by spiculated spinal osteophytes. METHODS This study reports a series of 14 patients with high-flow CSF leaks caused by spiculated spinal osteophytes who underwent ultrafast dynamic CT myelography between March 2009 and December 2010. There were 10 male and 4 female patients, with an average age of 49 years (range 37–74 years). The value of ultrafast dynamic CT myelography in depicting the CSF leak site was qualitatively assessed. RESULTS In all 14 patients, ultrafast dynamic CT myelography was technically successful at precisely demonstrating the site of the CSF leak, the causative spiculated osteophyte piercing the dura, and the relationship of the implicated osteophyte to adjacent structures. Leak sites included 3 cervical, 11 thoracic, and 0 lumbar levels, with 86% of the leaks occurring from C-5 to T-7. Information obtained from the ultrafast dynamic CT myelogram was considered useful in all treated CSF leaks. CONCLUSIONS Spinal osteophytes piercing the dura are a more frequent cause of high-flow CSF leaks than previously recognized. Ultrafast dynamic CT myelography adds value beyond standard dynamic myelography or digital subtraction myelography in the diagnosis and anatomical characterization of high-flow spinal CSF leaks caused by these osteophytes. This information allows for appropriate planning for percutaneous or surgical treatment.

SUMMARY:We have encountered 2 cases of parathyroid adenomas that are atypical because of their large size, cystic character, and faint enhancement compared with the typical solid parathyroid adenomas. Specifically, the enhancement pattern of a typical parathyroid adenoma in a multiphasic scan demonstrates rapid arterial enhancement and rapid washout on delayed imaging, whereas, comparatively, the 2 cystic parathyroid adenomas we encountered demonstrated less arterial phase enhancement and little washout on venous and delayed-phase imaging.ABBREVIATIONS: ANT ϭ anterior; I ϭ iodine; LAO ϭ left anterior oblique; PTH ϭ parathyroid hormone; RAO ϭ right anterior oblique; SPECT ϭ single-photon emission tomography; Tc ϭ technetium T ypically, the 4 parathyroid glands lie in close proximity to the thyroid gland but can lie anywhere along the path of descent of the pharyngeal pouches, from the mandible to the mediastinum. Each gland is composed mainly of chief cells, which respond to a decrease below a "set point" of circulating ionized calcium by releasing PTH in a homeostatic feedback loop mediated by calcium-sensing receptors on the cell surface.PTH increases the level of circulating calcium by receptormediated tubular resorption of calcium in the kidney, increasing osteoclast activity to stimulate release of calcium from the bone, and increasing activity of renal 1-hydroxylase, resulting in production of 1,25-dihydroxyvitamin D and increasing bowel calcium absorption.1 Hyperparathyroidism in all its forms is characterized by an increase in the set point for serum calcium, 2 which in turn leads to a serum calcium level above the reference range.With the advent of advanced parathyroid imaging, standard 4-gland exploration in cases of primary hyperparathyroidism has been superseded by minimally invasive parathyroidectomy targeted at the parathyroid adenoma. At our institution, the primary imaging technique used for the detection of parathyroid adenoma is the dual isotope 123 I/Tc99m sestamibi subtraction scan. Sonography has been the primary troubleshooting technique at our institution for the identification of parathyroid glands but has limited the visualization of ectopic parathyroid glands. With the increasing spatial resolution and speed of modern CT scanners, the utility of the multiphasic contrast-enhanced CT scan has been recognized and is more frequently requested by our surgeons in difficult cases.The technique of multiphasic CT for parathyroid imaging and the enhancement patterns of parathyroid adenomas have been previously described [3][4][5] and have proved useful in many cases for identification of parathyroid glands and preoperative planning. We have encountered 2 cases of parathyroid adenomas that are atypical because of their large size, cystic character, and faint enhancement. Case Reports Case 1A 54-year-old female patient was initially found on medical evaluation to have an elevated calcium concentration of 11.8 mg/dL and inappropriate elevation of the PTH level at 169 pg/mL (normal, 15-50 pg/mL).Preop...