Tohru Takeshita

Brown tumor with fluid-fluid levels in a patient with primary hyperparathyroidism: radiological findings

We report a case of a brown tumor with fluid-fluid levels in a patient with primary hyperparathyroidism. A 19-year-old woman presented with a 3-month history of pain in the left pubic region. The laboratory data showed elevated serum calcium and intact parathyroid hormone, confirming the diagnosis of primary hyperparathyroidism. Plain radiography and computed tomography (CT) showed an expansile lytic lesion of the superior ramus of the left pubis. The cortex was thinned. On magnetic resonance (MR) images, the lesion was solid and cystic. The solid area of the lesion showed heterogeneous low to intermediate signal intensity on T1-weighted images and heterogeneous low to high signal intensity on T2-weighted images. The cystic area showed several fluid-fluid levels on T2-weighted images. Dynamic contrast-enhanced MR images after administration of Gd-DTPA showed marked, early enhancement of the solid area of the lesion. A delayed image showed prolonged enhancement of the solid area and enhancement of the septa and walls of the cystic area. Histopathology of a biospy specimen showed fibroblastic proliferation, abundant giant cells, and focal hemosiderin deposition, which supported the diagnosis of a brown tumor. After removing the parathyroid adenoma, the brown tumor regressed and became sclerotic on radiographs.

Internal Hernias in the Era of Multidetector CT: Correlation of Imaging and Surgical Findings

Clinical diagnosis of internal hernias is challenging because of their nonspecific signs and symptoms. Many types of internal hernias have been defined: paraduodenal, small bowel mesentery-related, greater omentum-related, lesser sac, transverse mesocolon-related, pericecal, sigmoid mesocolon-related, falciform ligament, pelvic internal, and Roux-en-Y anastomosis-related. An internal hernia is a surgical emergency that can develop into intestinal strangulation and ischemia. Accurate preoperative diagnosis is crucial for appropriate management. Multidetector computed tomography (CT), with its thin-section axial images, high-quality multiplanar reformations, and three-dimensional images, currently plays an essential role in preoperative diagnosis of internal hernias. The diagnostic approach to internal hernias at multidetector CT includes detecting an intestinal closed loop, identifying the hernia orifice, and analyzing abnormal displacement of surrounding structures and key vessels around the hernia orifice and hernia sac. At each step, multidetector CT can depict pathognomonic findings. A saclike appearance suggests an intestinal closed loop in several types of internal hernias. Convergence, engorgement, and twisting of mesenteric vessels in the hernia orifice can be seen clearly at multidetector CT, especially with use of multiplanar reformations. For definitive diagnosis of an internal hernia, analysis of displacement of anatomic landmarks around the hernia orifice is particularly important, and thin-section images provide the required information. Detailed knowledge of the anatomy, etiology, and imaging landmarks of the various hernia types is also necessary. Familiarity with the appearances of internal hernias at multidetector CT allows accurate and specific preoperative diagnosis. (©)RSNA, 2015.

Squamous-lined cyst of the pancreas: Radiological-pathological correlation.

Pancreatic cystic lesions are increasingly being detected incidentally because of the increased use of cross-sectional imaging. Squamous-lined cysts of the pancreas (lymphoepithelial cyst, epidermoid cyst, and dermoid cyst) are rare cystic lesions lined with squamous epithelium. Distinguishing squamous-lined cysts from other cystic lesions of the pancreas is important to avoid unnecessary surgery, because squamous-lined cysts of the pancreas have no malignant potential. The purpose of this review is to describe findings on computed tomography and magnetic resonance imaging and the histopathological characteristics of squamous-lined cysts, and to summarize the key points of differential diagnosis for pancreatic cystic lesions.

Regional cerebral blood flow in a patient with Nasu-Hakola disease.

We report a functional neuroimaging study of a 43-year-old woman with Nasu-Hakola disease (NHD). Regional cerebral blood flow (rCBF) images were measured with technetium-99m ethyl cysteinate dimer single photon emission computed tomography (SPECT). rCBF was decreased in the bilateral frontal lobes and thalamus. This finding was consistent with the known underlying neuropathology in patients with NHD. Brain SPECT is useful for demonstrating the pathophysiologic brain region in patients with NHD.

Cystic lesions of the parotid gland: radiologic-pathologic correlation according to the latest World Health Organization 2017 Classification of Head and Neck Tumours

The latest World Health Organization 2017 Classification of Head and Neck Tumours includes a new chapter on tumors and tumor-like lesions of the neck and lymph nodes. Tumor-like lesions include a variety of cystic lesions of the parotid gland. Cystic lesions of the parotid gland can be divided into three groups: non-neoplastic cysts, benign tumors with macrocystic change, and malignant tumors with macrocystic change. It is important to distinguish these lesions from one another because treatment and patient management differ among the three groups. The purpose of this review is to describe the magnetic resonance imaging and scintigraphy findings and the histopathologic characteristics of each parotid gland lesion based on the latest World Health Organization 2017 Classification of Head and Neck Tumours and to summarize the key points of differential diagnosis for cystic lesions of the parotid gland.

Hydraulic analysis of the functional properties of saline-jet aspiration thrombectomy catheters

The purpose of this paper is to clarify the functional properties of a saline-jet aspiration thrombectomy catheter based on hydraulics. This catheter, developed by the authors, aspirates intravascular thrombi by means of the effect of a high-speed jet. We have derived the relationships between Qs, Qa, and p(n), where Qs is the water supply rate, Qa is the water aspiration rate and p(n) is the negative pressure created in the distal lumen of the catheter. The relationships are represented by simple equations using c1 and c2, where c1 and c2 are coefficients proper to the catheter. We have obtained c1 and c2 experimentally for three types of catheter with different distal shapes. Two practical conclusions are derived from this study. First, making a short taper at the distal end increases the negative pressure created and is advantageous for thrombus aspiration. Second, making the diameter of the inner tube and nozzle smaller is essential for improving the aspiration ability of the catheter.