Ct head protocols

CECT HEAD, NCCT HEAD, CT ORBIT, CT PITUITARY GLAND, CT CEREBRAL ANGIOGRAPHY

1. MAAJID MOHI UD DIN MALIK LECTURER COPMS,ADESH UNIVERSITY BATHINDA PUNJAB CT HEAD PROTOCOLS

2. COMPUTED TOMOGRAPHY (CT) - HEAD Computed tomography (CT) of the head uses special x-ray equipment to help assess head injuries, severe headaches, dizziness, and other symptoms of aneurysm, bleeding, stroke, and brain tumors. It also helps to evaluate your face, sinuses, and skull or to plan radiation therapy for brain cancer. In emergency cases, it can reveal internal injuries and bleeding quickly enough to help save lives .

3. WHAT IS CT SCANNING OF THE HEAD? Computed tomography, more commonly known as a CT or CAT scan, is a diagnostic medical imaging test. Like traditional x-rays, it produces multiple images or pictures of the inside of the body. The cross-sectional images generated during a CT scan can be reformatted in multiple planes. They can even generate three-dimensional images. These images can be viewed on a computer monitor, printed on film or by a 3D printer, or transferred to a CD or DVD .

4. CONTINUE... CT images of internal organs, bones, soft tissue and blood vessels provide greater detail than traditional x-rays, particularly of soft tissues and blood vessels. CT scanning provides more detailed information on head injuries,  stroke brain tumors and other brain diseases than regular radiographs (x-rays).

5. PREPARATION You should wear comfortable, loose-fitting clothing to your exam. You may need to wear a gown during the procedure. Metal objects, including jewelry, eyeglasses, dentures and hairpins, may affect the CT images. Leave them at home or remove them prior to your exam. You may also be asked to remove hearing aids and removable dental work. Women will be asked to remove bras containing metal underwire. You may be asked to remove any piercings, if possible.

6. CONTINUE... You will be asked not to eat or drink anything for a few hours beforehand, if contrast material will be used in your exam. You should inform your physician of all medications you are taking and if you have any allergies. If you have a known allergy to contrast material, your doctor may prescribe medications (usually a steroid) to reduce the risk of an allergic reaction. To avoid unnecessary delays, contact your doctor before the exact time of your exam. Also inform your doctor of any recent illnesses or other medical conditions and whether you have a history of heart disease, asthma, diabetes, kidney disease or thyroid problems. Any of these conditions may increase the risk of an adverse effect.

7. WHAT ARE SOME COMMON USES OF THE PROCEDURE? CT scanning of the head is typically used to detect: Bleeding, brain injury and skull fractures in patients with head injuries. Bleeding caused by a ruptured or leaking aneurysm in a patient with a sudden severe headache. A blood clot or bleeding within the brain shortly after a patient exhibits symptoms of a stroke .

8. CONTINUE... A stroke, especially with a technique called  CT Perfusion of the Head . Brain tumors . Enlarged brain cavities (ventricles) in patients with hydrocephalus. Diseases or malformations of the skull . CT scanning is also performed to: Evaluate the extent of bone and soft tissue damage in patients with facial trauma, and planning surgical reconstruction. Diagnose diseases of the temporal bone on the side of the skull, which may be causing hearing problems .

9. CONTINUE... Determine whether inflammation or other changes are present in the paranasal sinuses. Plan radiation therapy for cancer of the brain or other tissues. Guide the passage of a needle used to obtain a tissue sample (biopsy) from the brain. Assess aneurysms, arteriovenous malformations, and blood vessels through a technique called CT angiography. 

10. WHAT ARE THE BENEFITS VS. RISKS? Benefits CT scanning is painless, noninvasive and accurate. A major advantage of CT is its ability to image bone, soft tissue and blood vessels all at the same time. Unlike conventional x-rays, CT scanning provides very detailed images of many types of tissue as well as the lungs, bones, and blood vessels. CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives .

11. CONTINUE... CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems. CT is less sensitive to patient movement than MRI. CT can be performed if you have an implanted medical device of any kind, unlike MRI. A diagnosis determined by CT scanning may eliminate the need for exploratory surgery and surgical biopsy. No radiation remains in a patient's body after a CT examination. X-rays used in CT scans should have no immediate side effects .

12. RISKS There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk. The effective radiation dose for this procedure varies. See the Radiation Dose in X-Ray and CT Exams page for more information about radiation dose. Women should always tell their doctor and x-ray or CT technologist if there is any chance they are pregnant. See the Safety in X-ray, Interventional Radiology and Nuclear Medicine Procedures page for more information about pregnancy and x-rays .

13. CONTINUE... CT scanning is, in general, not recommended for pregnant women unless medically necessary because of potential risk to the baby. This risk is, however, minimal with head CT scanning. IV contrast manufacturers indicate mothers should not breastfeed their babies for 24-48 hours after contrast material is given. However, the most recent American College of Radiology (ACR) Manual on Contrast Media reports that studies show the amount of contrast absorbed by the infant during breastfeeding is extremely low. For further information please consult the  ACR Manual on Contrast Media  and its references .

14. CONTINUE... The risk of serious allergic reaction to contrast materials that contain iodine is extremely rare, and radiology departments are well-equipped to deal with them. Because children are more sensitive to radiation, they should have a CT exam only if it is essential for making a diagnosis and should not have repeated CT exams unless absolutely necessary. CT scans in children should always be done with low-dose technique .

15. CT ROUTINE ADULT HEAD (NCCT BRAIN) PROTOCOL Indications: Acute head trauma Stroke Intracranial bleed Headache Epilepsy Neoplasms- Pre or postoperative evaluation Hydrocephalus Abscess

16. CONTRAINDICATIONS Pregnancy Hypersensitivity to iodinated contrast media. Renal impairment (Creatinine >1.5mg/dl )

17. POSITION Patient Position: Spine with head first arms bilaterally downwards, with the head in the head holder. Center the table height such that external auditory meatus (EAM) is at center of the gantry. To decrease the ocular lens exposure, the scan angle should be parallel to a line created by the supraorbital ridge and the inner table of the posterior margin of the foramen magnum. Topogram Direction: Craniocaudal Scan Type: Axial Position/Landmark: 2-3cm (20-30mm) above the vertex. Start Location: Skull base. End Location: Skull vertex. Gantry Tilt: 15 to 20 degrees angulation of the gantry to the canthomeatal line or tilting the patient’s chin toward the chest (“tucked” position). DFOV: 22cm

18. CONTINUE…. Contrast: Nil Slice Thickness: 2- 5 mm Algorithm: standard, bone Respiratory Phase: None Tube Voltage (Kv): 120 Tube Current (mAs): 300-450 Rotation Time (s): 1 Pitch: 10.65 mm Contrast: Nil Image Form at: DICOM

19. Topogram of head with scan lines showing the plane and scan range Axial NCCT head showing EDH

20. CONTRAST ENHANCED CT HEAD PROTOCOL Indications: Suspicion of mass Known primary tumour Metastases Aneurysm Abscesses Meningitis Patient Position: Spine with head first arms bilaterally downwards, with the head in the head holder. Center the table height such that external auditory meatus (EAM) is at center of the gantry. To decrease the ocular lens exposure, the scan angle should be parallel to a line created by the supraorbital ridge and the inner table of the posterior margin of the foramen magnum Topogram Direction: Craniocaudal

21. CONTINUE…. Scan Type: Helical Position/Landmark: 2-3 cm (20-30 mm) above the vertex. Start Location: 1 cm inferior to Skull base. End Location: 1 cm superior to Skull vertex. Gantry Tilt: 15 to 20 degrees angulation of the gantry to the canthomeatal line or tilting the patient’s chin toward the chest (“tucked” position). DFOV: 25cm Contrast : Nonionic low osmolar Iodinated Contrast media Contrast Administration: IV Volume: 60-100 ml Rate of Injection: 2-3 ml /s Slice Thickness: 2 - 5 mm

22. CONTINUE…. Scan Delay: 30-50sec Algorithm: Standard, Soft tissue Recons and Reformations : MPR, MIP Respiratory Phase: Any Tube Voltage (Kv): 135-240 Tube Current (mAs): 150-220 Rotation Time (s): 0.5-0.7 Image Format : DICOM

23. Topogram of head with scan lines showing the plane and scan range CECT axial image showing normal brain

24. CT TEMPORAL BONES PROTOCOL Indications: Inflammatory middle ear diseases Cholesteatoma Hearing Loss Trauma

25. CONTINUE…. Mastoiditis Neoplastic lesions Congenital anomalies

26. AXIAL PROJECTION Patient Position: Spine with head first, head in head rest. Topogram Direction: Craniocaudal in axial plane or in spine position. Scan type: Helical Position /landmark: Midforehead in axial plane. Start Location: Skull base End Location: Superior margin of petrous temporal bone

27. CONTINUE…. Gantry Tilt: No tilt in axial plane. DFOV: 20 cm Scan field of view: 25 cm Contrast Administration: IV Volume: 80-100 ml Rate of Injection: 2-3 ml /s Scan Delay: 30-40 sec Algorithm: Bone Slice Thickness: 1-2mm Tube Voltage (Kv): 140 Tube Current (mAs): 350 Rotation Time (s): 0.5 Image Form at: DICOM

28. CORONAL PROJECTION Patient Position: Prone with head first, with extended neck and chin on chin rest. Topogram Direction: Posterior to anterior in coronal plane or in prone position Scan Type: Helical Position/Landmark: 2-3 cm (20-30 mm) anterior to the forehead in coronal plane . Start Location: Anterior margin of petrous temporal bone End Location: Posterior margin of petrous temporal bone Gantry Tilt: 17-23 degrees to make the scanning plane perpendicular to bony palate in coronal plane. DFOV: 18 cm Scan field of view: 25 cm

29. CONTINUE…. Contrast : Nonionic low osmolar Iodinated Contrast media Contrast Administration: IV Volume: 80-100 ml Rate of Injection: 2-3 ml /s Algorithm: Standard, Bone Recons and Reformations : MPR, MIP Scan Delay: 30-40 sec Slice Thickness : 1-3mm Tube Voltage (Kv): 140 Tube Current (mAs): 150-350 Rotation Time (s): 0.5 Image Form at: DICOM

30. Topogram of temporal bone showing scan range Coronal section of temporal bone

31. CT PITUITARY GLAND PROTOCOL Indications: Pituitary adenoma Suspected/ known pituitary mass Inflammation Pituitary tumor Contraindications to MRI

32. PROTOCOL Patient/Position: Spine with IOML perpendicular to table and head in a symmetrical position. Topogram Direction: Caudocranial Scan Type: Helical Position/Landmark: Start Location: Bottom of sella End Location: Hypothalamus Breath hold : None DFOV: 22 cm Scan field of view: 25 cm Contrast : Nonionic low osmolar Iodinated Contrast media Contrast Administration: IV

33. CONTINUE…. Volume: 80-100 ml Rate of Injection: 3-3.5 ml /s Algorithm: Standard, soft tissue, bone, Recons and Reformations : MPR, MIP Scan Delay: 30 sec Slice Thickness : 1-3 mm Tube Voltage (Kv): 130-150 Tube Current (mAs): 220-250 Rotation Time (s): 0.5 Image Form at: DICOM

34. Topogram of sella showing scan range CT axial image of pituitary gland shows pituitary adenomas

35. CT CEREBRAL PERFUSION PROTOCOL Indications: Acute stroke Evaluate vasospasm Suspected cerebral infarction Vasculitis Brain tumor Transient ischemic attack Follow up after ischemic stroke Assessment of reperfusion after treatment of acute stroke

36. PROTOCOL Patient/Position: Spine with head first arms bilaterally downwards, with the head in the head holder. Center the table height such that external auditory meatus (EAM) is at center of the gantry. Topogram Direction: Caudocranial Scan Type: Helical Position/Landmark: At the level of the canthomeatal line Start Location: 1cm inferior to skull base End Location: Skull vertex Gantry Tilt: 15 to 20 degrees angulation of the gantry to the canthomeatal line is advisable if possible or tilting the patient’s chin toward the chest (“tucked” position). Breath hold : None DFOV: 20 cm Scan field of view: 25 cm Contrast : Nonionic low osmolar Iodinated Contrast media

37. CONTINUE…. Contrast Administration: IV Volume: 80-100 ml Rate of Injection: 2-3 ml /s Algorithm: Standard, soft tissue Recons and Reformations : MPR, MIP, SSD Scan Delay: 30-40 sec Slice Thickness : 3-5 mm Tube Voltage (Kv): 80-100 Tube Current (mAs): 120-150 Rotation Time (s): 0.8 Image Form at: DICOM

38. ACUTE ICA ISCHEMIC PENUMBRA

39. CT CEREBRAL VENOGRAM PROTOCOL Indications: Cerebral venous thrombosis Patient/Position: Spine with head first arms bilaterally downwards, with the head in the head holder. Center the table height such that external auditory meatus (EAM) is at center of the gantry. Topogram Direction: Caudocranial Scan Type: Helical Position/Landmark: 2-3 cm (20-30 mm) above the vertex.

40. CONTINUE…. Start Location: 1cm inferior to skull base End Location: skull vertex Breath hold : Any DFOV: 18 cm Scan field of view: 25 cm Contrast : Nonionic low osmolar Iodinated Contrast media Contrast Administration: IV Volume: 80-100 ml Rate of Injection: 5.00 ml /s Algorithm: Standard, soft tissue Recons and Reformations : MPR, MIP, VRT, SSD

41. CONTINUE…. Scan Delay: 45 sec Slice Thickness : 1-1.5 mm Tube Voltage (Kv): 130-150 Tube Current (mAs): 220-450 Rotation Time (s): 0.5 Image Form at: DICOM

42. CEREBRAL VENOUS THROMBOSIS

43. CEREBRAL VENOUS THROMBOSIS IN ADULTS

44. Multi-section CT Venography of the Dural Sinuses and Cerebral Veins by Using Matched Mask Bone Elimination