Nam Joon Lee

Extraadrenal Paragangliomas of the Body: Imaging Features

OBJECTIVE This article illustrates the anatomic distribution of the healthy paraganglion system and the imaging and pathologic features of various extraadrenal paragangliomas occurring in the head and neck, chest, and abdomen. CONCLUSION Although paragangliomas can occur in a variety of anatomic locations, the majority are seen in relatively predictable regions of the body. Extraadrenal paragangliomas have nearly identical imaging features, including a homogeneous or heterogeneous hyperenhancing soft-tissue mass at CT, multiple areas of signal void interspersed with hyperintense foci (salt-and-pepper appearance) within tumor mass at MRI, and an intense tumor blush with enlarged feeding arteries at angiography.

Intra-articular ganglion cysts of the knee: clinical and MR imaging features

Abstract The purpose of this study was to present clinical and MR imaging features of intra-articular ganglion cysts of the knee. Retrospective review of 1685 consecutive medical records and MR examinations of the knee performed at three imaging centers allowed identification of 20 patients (13 men and 7 women; mean age 35 years), in whom evidence of intra-articular ganglion cyst was seen. Of the 20 ganglion cysts, 5 were found in the infrapatellar fat pad, 10 arose from the posterior cruciate ligament, and 5 from the anterior cruciate ligament. Three of five patients with ganglion cyst in the infrapatellar fat pad had a palpable mass. In 7 of 15 patients with ganglion cyst in the intercondylar notch, exacerbation of pain occurred in a squatting position. On four MR arthrographies, ganglion cysts were an intra-articular round, lobulated, low signal intensity lesion. Five cases of fat-suppressed contrast-enhanced T1-weighted SE images demonstrated peripheral thin rim enhancement. The clinical presentation of intra-articular ganglion cyst is varied according to its intra-articular location. The MR appearance of intra-articular ganglion cyst is characteristic and usually associated with the cruciate ligament or the infrapatellar fat pad. Magnetic resonance arthrography has no definite advantage over conventional MR in the evaluation of the lesion. For intra-articular ganglion cyst in the infrapatellar fat pad, fat-suppressed contrast-enhanced MR imaging could be useful, because a thin, rim-enhancing feature of intra-articular ganglion cyst allows it to be distinguished from synovial hemangioma and synovial sarcoma.

Experience-Dependent Plasticity of Cerebellar Vermis in Basketball Players

The cerebellum is involved in the learning and retention of motor skills. Using animal and human models, a number of studies have shown that long-term motor skill training induces structural and functional plasticity in the cerebellum. The aim of this study was to investigate whether macroscopic alteration in the volume of cerebellum occurs in basketball players who had learned complex motor skills and practiced them intensively for a long time. Three-dimensional magnetic resonance imaging volumetry was performed in basketball players (n = 19) and healthy controls (n = 20), and the volumes of cerebellum and vermian lobules were compared between two groups. Although there was no macroscopic plasticity detected in the cerebellum as a whole, detailed parcellation of cerebellum revealed morphological enlargement in the vermian lobules VI–VII (declive, folium, and tuber) of basketball players (P < 0.0166), which might then be interpreted as evidence for plasticity. This finding suggests that the extensive practice and performance of sports-related motor skills activate structural plasticity of vermian lobules in human cerebellum and suggests that vermian VI–VII plays an important role in motor learning.

Inflammatory myofibroblastic tumor of the larynx

Inflammatory myofibroblastic tumor, composed of myofibroblastic spindle cells with acute and chronic inflammatory cells, is an unusual, benign solid mass that mimics a neoplastic process.

High-resolution ct appearance of miliary tuberculosis

Objective The purpose of this study was to define the range of abnormalities and to assess the contribution of high-resolution CT (HRCT) in the evaluation of miliary tuberculosis involving the lung parenchyma. Materials and Methods The authors retrospectively reviewed HRCT scans of 11 patients with microbiologically or clinically proved miliary tuberculosis. Results In 10 patients, the most characteristic HRCT finding of miliary tuberculosis was the presence of small nodules uniformly distributed throughout both lungs. The profusion of nodules was numerous in all 10 patients. High-resolution CT scans showed both sharply and poorly defined, small nodules varying in sizes from 1 to 2 mm (n = 6), 1 to 3 mm (n = 2), and 1 to 4 mm (n = 2) in diameter. These nodules had a diffuse random distribution in the secondary lobule in all 10 patients. In 1 of the 10 patients with small nodules on HRCT, chest radiography had shown no evidence of miliary nodules in the lung. In addition to nodules, HRCT showed diffuse or localized reticular opacities superimposed on nodules in five patients, especially in the lower lung zones. In 1 of all 11 patients, ground-glass attenuation was the predominant abnormality seen on HRCT. Conclusion We believe that in the appropriate clinical situation, miliary tuberculosis may be suggested on HRCT. Moreover, in cases with no evidence of miliary nodules on the chest radiograph, HRCT scan may depict miliary nodules in the lung parenchyma.

Magnetic resonance image-based cerebellar volumetry in healthy Korean adults.

The effects of age and gender on cerebellar size have not been established yet. To understand these effects, the area of cerebellar vermis and the volume of cerebellum were measured using serial magnetic resonance images of 124 Korean adults free of neurologic symptoms and signs. Cerebellar volume of male was significantly larger than that of female, although the size of vermis did not show significant gender difference. Correlation analysis revealed that cerebellar volume was not affected by aging. Regressional analysis demonstrated that female vermis had a tendency to shrink after age of 50, whereas male vermis and total cerebellar volume in both sexes were not altered with aging. The different response of vermis with aging and maintenance of cerebellum volume need to be more explored.

Diffusion-weighted magnetic resonance imaging in the syndrome of acute bilateral basal ganglia lesions in diabetic uremia

In this report, we have presented a diabetic patient with uremia, in which acute Parkinsonism occurred, coupled with acute mental confusion, after a sudden increase in blood urea nitrogen and serum creatinin levels. Diffusion‐weighted magnetic resonance imaging revealed a unique cytotoxic‐type edema in the bilateral basal ganglia during the acute phase. Signal alterations were shown to regress in accordance with the normalized apparent diffusion coefficient (ADC) values, but irreversible cystic degeneration developed in the globus pallidus, with the very low preceding ADC values.

Sonographic evaluation of breast nodules: comparison of conventional, real-time compound, and pulse-inversion harmonic images.

Objective To compare the use of conventional, real-time compound, and pulse-inversion harmonic imaging in the evaluation of breast nodules. Materials and Methods Fifty-two breast nodules were included in this study, conducted between May and December 2000, in which conventional, real-time compound, and pulse-inversion harmonic images were obtained in the same plane. Three radiologists, each blinded to the interpretations of the other two, evaluated the findings, characterizing the lesions and ranking the three techniques from grade 1, the worst, to grade 3, the best. Lesion conspicuity was assessed, and lesions were also characterized in terms of their margin, clarity of internal echotexture, and clarity of posterior echo pattern. The three techniques were compared using Friedmans test, and interobserver agreement in image interpretation was assessed by means of the intraclass correlation coefficient. Results With regard to lesion conspicuity, margin, and internal echotexture of the nodules, real-time compound imaging was the best technique (p < 0.05); in terms of posterior echo pattern, the best was pulse-inversion harmonic imaging (p < 0.05). Real-time compound and pulse inversion harmonic imaging were better than conventional sonography in all evaluative aspects. Interobserver agreement was greater than moderate. Conclusion Real-time compound and pulse-inversion harmonic imaging procedures are superior to conventional sonography in terms of both lesion conspicuity and the further characterization of breast nodules. Real-time compound imaging is the best technique for evaluation of the margin and internal echotexture of nodules, while pulse-inversion harmonic imaging is very effective for the evaluation of the posterior echo patterns.

Acinic cell carcinoma of the head and neck: radiologic-pathologic correlation.

Objective: To describe and correlate the imaging and pathologic findings of acinic cell carcinoma (ACC) in the head and neck. Methods: We reviewed the radiologic findings of 12 patients with pathologically proven ACC in the head and neck. They were 6 males and 6 females (ages: 5-75 years, mean 36 years) who undergoing computed tomography (CT, n = 9) and CT with magnetic resonance (MR) imaging (n = 3). Results: The lesions in the superficial lobe of the parotid gland were solid (n = 7), cystic (n = 1), and cystic mass with mural nodule (n = 1) on CT. A parapharyngeal lesion was cystic mass with mural nodule, and a submandibular and a palate tumor were cystic lesions on CT. All solid masses in the parotid gland (n = 7) included focal low-attenuating portions on CT, which were microcyst, hemorrhage, or necrosis on pathologic examination. We could not find intratumoral calcifications or metastatic lymphadenopathy on imaging and histologic studies in all 12 cases. Internal hemorrhage on the MR images was seen in a parapharyngeal and a parotid lesion. Conclusion: Although ACC appears to have nonspecific imaging findings, familiarity with some imaging features can be helpful for differential diagnosis of head and neck tumors.

Cut-off value for needle washout thyroglobulin in athyrotropic patients†

The purpose of this study was to determine the appropriate cut‐off value for fine needle aspiration‐thyroglobulin (FNA‐Tg) associated with postoperative recurrences and validate the diagnostic efficacy of FNA‐Tg in patients after total thyroidectomy compared with concomitant cytology (C).