CT FEMUR.ppt showing how to operate a ct

CT femur

1. CT FEMUR RAD MUSILIU MOBOLAJI RAD NLEMCHUKWU REJOICE AKACHUKWU DATE: 25-09-2024

2. TABLE OF CONTENT Introduction Gross & Radiographic anatomy Common indications Contraindications Patient preparation Techniques Scan parameters Basic parameters for quality images and acceptable dose for investigation. Appropriate windowing, slice thickness, scan mode, rotation time and FOV. Reformating , image critic, film printing. References

3. INTRODUCTION A thigh CT scan is the imaging of the human thigh using a CT scanner. The femur is the only bone in the thigh and the longest bone in the body. It acts as the site of origin and attachment of many muscles and ligaments, and can be divided into three parts;proximal, shaft and distal.

4. GROSS AND RADIOGRAPHIC ANATOMY

5. PROXIMAL The proximal aspect of the Femur articulates with the acetabulum of the pelvis to form the hip joint. it consists of a head and neck, and two bony processes- the greater and lesser trochanters. There are also two bony ridges connecting the two trochanters; the intertrochanteric line anteriorly and the trochanteric crest posteriorly. HEAD- articulates with the acetabulum of the pelvis to form the hip joint.it has a smooth surface, covered with articular cartilage( except for a small depression - the Fovea- where ligamentum teres attaches).

6. NECK Connects the head ofthe femur with the shaft. it is cylindrical, projecting in a superior and medial direction. Greater trochanter: the most lateral projection of bone that originates from the anterior aspect, just lateral to the neck. it is the site of attachment for many of the muscles in the gluteal region such as gluteus medius,gluteus minimus and piriformis. Lesser trochanter: ( smaller) it projects from the posteromedial side of the femur,just inferior to the neck-shaft junction

7. INTERTROCHANTERIC LINE A ridge of bone that runs in an infero medial direction on the anterior surface of the femur , spanning between the two trochanters. it is the site of attachment for the ilio femoral ligament ( the strongest ligament of the hip joint). it also serves as the anterior attachment of the hip joint capsule. Intertrochanteric crest : it is located on the posterior surface of the femur

8. ANTERIOR POSTERIOR

9. THE SHAFT The shaft of the femur descends in a slight medial direction. this brings the knee closer to the body’s Centre of gravity , increasing stability. on the posterior surface of the femoral shaft, there are roughened ridges of bone , called the linea aspera . this splits distally to form the medial and lateral supracondylar lines. the flat popliteal surface lies between them. proximally , the medial border of the linea aspera becomes the pectineal line. the lateral border becomes the gluteal tuberosity, where the gluteus Maximus attaches. Distally, the linea aspera widens and forms the floor of the popliteal fossa , the medial and the lateral borders form the medial and lateral supracondylar lines. the medial supracondylar line ends at the adductor tubercle, where the adductor Magnus attaches.

10. SHAFT

11. DISTAL The distal end of the femur is characterised by the presence of the medial and lateral condyles,which articulate with the tibia and patella to form the knee joint. Medial and lateral condyles- rounded areas at the end of the femur. the posterior and inferior surfaces articulate with the tibia and menisci of the kneee, while the anterior surface articulates with the patella. Medial and lateral epicondyles- bony elevations on the non -articular areas of the condyles. the medial epicondyle is the larger. intercondylar fossa - a deep notch on the posterior surface of the femur, between the two condyles.

12. ANTERIOR POSTERIOR

13. Muscles of anterior and medial compartment

14. Muscles of the Femur

15. GROSS AND RADIOGRAPHIC ANATOMY

16. Vascular supply and venous drainage The main artery of the lower limb is the femoral artery . it is a continuation of the external iliac artery (terminal branch of the abdominal aorta). The external iliac becomes the femoral artery when it crosses under the inguinal ligament and enters the femoral triangle, the profunda femoris artery arises from the postero lateral aspect of the femoral artery. It gives off three main branches: Perforating branches : consists of three or four arteries that perforate the adductor magnus , contributing to the supply of the muscles in the medial and posterior thigh. Lateral femoral circumflex artery: wraps round the anterior, lateral side of the femur, supplying some of the muscles on the lateral aspect of the thigh

17. Vascular supply and venous drainage

18. Vascular supply and venous drainage Once the popliteal vein has entered the thigh, it is known as the femoral vein. It is situated anteriorly, accompanying the femoral artery. The deep vein of the thigh (profunda femoris vein) is the other main venous structure in the thigh. Via perforating veins, it drains blood from the thigh muscles. It then empties into the distal section of the femoral vein. The femoral vein leaves the thigh by running underneath the inguinal ligament, at which point it is known as the external iliac vein.

19. Vascular supply and venous drainage

20. INNERVATION The femur itself doesn’t have direct innervation, but the muscles and skin around it are innervated by several nerves, primarily the femoral nerve. Here’s a brief overview: Femoral Nerve: Originates from the lumbar plexus (L2-L4) and is the largest branch of this plexus. It innervates the anterior thigh muscles, including the hip flexors (pectineus, iliacus, sartorius) and knee extensors (quadriceps femoris)

21. INNERVATION

22. Vascular supply and veneous drainage Medial femoral circumflex artery : wraps round the posterior side of the femur,supplying its neck and head.

23. GROSS AND RADIOGRAPHIC ANATOMY

24. COMMON INDICATIONS FOR CT FEMUR Soft tissue mass of the femur Osteomyelitis/Soft tissue infection of the thigh Puncture wound, possible foreign body Necrotizing fascitis highly suspected Soft tissue gas on x-ray, no puncture wound Fracture Trauma Post-operative evaluation

25. PATIENT PREPARATION A satisfactory written consent form must be taken from the patient before entering the scanner room. Ask the patient to remove opacities around the waist down and can change to the hospital gown. Properly explain the procedure to the patient. Instruct the patient to keep still.

26. CONTRAINDICATIONS Pregnancy Renal Impairment for contrast studies Previous contrast reaction for contrast studies

27. PATIENT POSITIONING AND TECHNIQUES Patient lies leg first supine. You can rest the patients head on a pillow and ensure the hands are not around the region of interest. You can rotate the limb to centralize the patella over the femur. Ensure the horizonal light aligns midway between the anterior and posterior bother of the thigh. Ensure the vertical beam aligns with the midline of the body. Center midway between the ASIS.

28. PATIENT POSITIONING AND TECHNIQUES

29. SCAN PARAMETERS Scan mode: Helical Slice thickness: 3 mm Rotation time: 0.5-1 second Tube voltage: 80 - 140 kVp Tube current: 200-300 mA FOV: largest field of view (FOV) reasonable for the study Dose reduction techniques: ALARA, AEC Appropriate Windowing Soft tiisue window WW/WL : 400/7 HU Bone window WW/WL : 1500/150 HU WW- WINDOW WIDTH WL- WINDOW LEVEL

30. BASIC PARAMETERS FOR QUALITY IMAGES AND ACCEPTABLE DOSE FOR INVESTIGATION. The images should be scanned and reconstructed with the largest field of view (FOV) reasonable for the study. Sometimes the field of view is too small and it is difficult to review the images. Image reconstruction should be done with both soft tissue windows (400/7) as well as high resolution bone algorithm windows which are reviewed at a different window width/levels (1500/150). The high resolution bone images are optimal for detecting subtle fractures. The soft tissue windows are best for looking at muscle, soft tissues and the vessels. 3D mapping is ideal especially in cases of complex fractures. MIP imaging is good for vessel mapping and detecting small bleeds while VRT/CR is ideal for looking at bone and soft tissue. VRT - Volume Rendering Technique. CR - Cinematic Rendering. When looking at bone with metal in place dual energy CT protocols will be helpful to decrease the streak artifact present. Streak artifact: the streaking artifact appears as multiple dark streaking bands.

31. REFORMATTING, IMAGE CRITIQUE, FILM PRINTING . Reformatting - Multi-planar reformation (MPR) (into Coronal and Sagittal views) - Maximum intensity projection (MIP) - Volume rendering (VR) or Cinematic Rendering (CR) Image Critique - Image quality: Sharpness, noise, artifacts - Anatomy: Organs, structures, lesions - Pathology: Detection, characterization Film Printing - Image resolution - Image size - Film type - Printer

32. IMAGE CRITIQUE Fracture on the shaft of the left femur

33. IMAGE CRITIQUE Mass in the thigh.

34. IMAGE CRITIQUE Aneurysmal Cyst bonein the distal femur

35. IMAGE CRITIQUE Bone Infarct in distal Femur

36. REFERENCES CTISUS RADIOPEDIA LIVESCIENCE GOOGLE

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