TAISHAN MEDICAL UNIVERSITY Schodl of Radiology SETA 6"Semester Final Exams,September Session 2009 Time -2.30 houn Full Marks70 Date-12 January,2010 Pass marks -42 Attempt all questions 1.What are the types of ultrasound transducer?How do you choose a propertransducer when linear array transducer,sector transducer.curved array transducer and special transducers The type of transducer selected for a particular examination depends upon several factors The type of examination: The echocardiographic examination is performed with a sector transducer(3.5MHz).Obstetric and gynecologic scans are usually performed with a curved or linear array transducer(3.5MHz). The size of the patient ●For children:1oMHz Special transducers have been produced to help view specific areas 2 Describe CT features of Cerebral Infarction Three phases may be identified:acute,subacute and chronic In the acute phase:about 60%of scans may be considered normal within the first fewhours some subtle early signs may be detected loss of grey-white matter interface >obscuration of the lentiform nucleus hyperdensity of the middle cerebral artery A rapid development of the picture may be seen after 6-8 hours with the development of cytotoxic oedema.the infarcted area becomes markedly hypodense with involvement of both grey and white matter,usually in a wedge-shaped area comresponding to the region of distribution of the occluded vessel about 15-20%of cases haemorrhagic foci may be detected after 24-48 hours 3.Describe the imaging features of Meningioma. .CT:shows a well marginated oval or lobulated mass.attached to the dura at an obtuse angle.Most lesions are homogeneously hyperdense,some isodense and a few hypodense ReuTiZie Pou. Ren Ti Zie Pou. Page 4 Taishan medical university School of Radiology SET A 6 th Semester Final Exams, September Session 2009 Time – 2. 30 hours Full Marks- 70 Date– 12th January, 2010 Pass marks – 42 Attempt all questions 1. What are the types of ultrasound transducer? How do you choose a proper transducer when different parts of a patient are examined ? The types of ultrasound transducer include linear array transducer, sector transducer ,curved array transducer and special transducers. The type of transducer selected for a particular examination depends upon several factors: ⚫ The type of examination: The echocardiographic examination is performed with a sector transducer(3.5MHz). Obstetric and gynecologic scans are usually performed with a curved or linear array transducer(3.5MHz). ⚫ The size of the patient ⚫ For adults : 3.5MHz, ⚫ For children :10MHz Special transducers have been produced to help view specific areas. 2. Describe CT features of Cerebral Infarction. • Three phases may be identified: acute, subacute and chronic • In the acute phase :about 60% of scans may be considered normal within the first few hours • some subtle early signs may be detected : ➢ loss of grey-white matter interface ➢ obscuration of the lentiform nucleus ➢ hyperdensity of the middle cerebral artery ➢ A rapid development of the picture may be seen after 6-8 hours with the development of cytotoxic oedema , the infarcted area becomes markedly hypodense with involvement of both grey and white matter , usually in a wedge-shaped area corresponding to the region of distribution of the occluded vessel ➢ about 15-20% of cases haemorrhagic foci may be detected after 24-48 hours 3. Describe the imaging features of Meningioma. • CT： shows a well marginated oval or lobulated mass, attached to the dura at an obtuse angle. Most lesions are homogeneously hyperdense, some isodense and a few hypodense