Imaging findings in mandibular primitive neuroectodermal tumour: a report of a rare case and review of the literature

Primitive neuroectodermal tumours (PNETs) are aggressive undifferentiated tumours that occur mainly in the central nervous system (CNS). Reviewing the literature, only six cases of primary PNET of the mandible have been reported. These rare tumours are usually overlooked in clinical practice. An 18-year-old woman who presented with dental caries and left cheek swelling was initially diagnosed with facial cellulitis, but the swelling persisted despite adequate intravenous antibiotic therapy. Subsequent ultrasound and MR examinations revealed a tumour originating from the left mandibular ramus. The ultrasonography-guided percutaneous core needle biopsy confirmed the diagnosis of peripheral PNET. The radiographic features of mandibular PNETs are similar to those of PNETs in other regions, except for haemorrhage, necrosis and calcification. In addition, this is the first reported case with sonographic and MR images of this rare tumour, and the first case that was diagnosed based on the ultrasonography-guided percutaneous core needle biopsy. Using these image characteristics, mandibular PNETs can be diagnosed more accurately.

Ruptured mediastinal cystic teratoma with intrapulmonary bronchial invasion: CT demonstration

Ruptured cystic mediastinal teratoma is rare. The diagnosis of this condition and a clear demonstration of its associated complications are important for defining the surgical approach. We report the CT findings of a case of mediastinal cystic teratoma before and after rupture. CT features of bursting of the spherical fatty compound and intrapulmonary bronchial invasion have not been previously described.

Hepatic calcification by sequelae of chronic schistosomiasis japonica: report of four cases

Due to the elimination of intermediate hosts and the improvement of clinical care, most parasitic infections have been effectively controlled in developing countries. Recently, the increase of the worldwide tourism, especially to Mainland China, and the migration of overseas workers from endemic countries have led to more parasitic infections that should not be overlooked by physicians. Assessment of diffuse liver disease with physical examination and laboratory findings is notoriously inaccurate. Thus, physicians use liver biopsy for accurate diagnoses. We present 4 patients with hepatic schistosomiasis japonica which were diagnosed using imaging before liver biopsy. Hepatic schistosomiais japonica has a tendency to cause dystrophic calcification and fibrosis in the liver. According to the results, a combination of ultrasonography and computed tomography (CT), used to recognize characteristic calcification patterns, seem useful to physicians for accurate diagnoses. Thus, unnecessary biopsy procedures can be avoided.

An SRRC elliptically polarizing undulator prototype to examine mechanical design feasibility and magnetic field performance

In this work, a 1 m long Sasaki-type elliptically polarizing undulator (EPU) prototype with 5.6 cm period length is used to examine the mechanical design feasibility as well as magnetic field performance. The magnetic field characteristics of the EPU5.6 prototype at various phase shifts and gap motion are described. The field errors from mechanical tolerances, magnet block errors, end field effects and phase/gap motion effects are analysed. The procedures related to correcting the field with the block position tuning, iron shimming and the trim blocks at both ends are outlined.

A dynamic local bump system for producing synchrotron radiation with an alternating elliptical polarization

To facilitate high-sensitivity soft X-ray magnetic circular dichroism experiments, a dynamic local bump system has been developed at the SRRC storage ring. This system was devised to vary dynamically the vertical slope of the electron beam in a bending magnet, producing, in the electron orbit plane, soft X-rays with an alternating elliptical polarization. The local bump was created by using two pairs of vertical correctors located on each side of the bending magnet. The bump strength coefficient was obtained both from calculated estimation and from measured beam-response matrices. Control electronics for proper bump strength settings were designed to incorporate the existing orbit-corrector function. A corresponding graphic user interface was implemented so that the bump amplitude could be easily adjusted. The performance of this system is presented. Disturbance on the stored electron beam orbit was observed while flipping the corrector polarity during EPBM (elliptical polarization from bending magnets) operation. A local feedback loop, developed to eliminate such disturbance on other beamlines, is also described.