Diagnostic Testing Martha Pyron MD N Hwy 183, Ste. 150 Austin, Texas, (512)

Overview Plain film Radiographs CTMRIArthrogram Venogram / Arteriogram Bone Scan (Radionucleotide scan) USFluoroscopy

Plain Radiographs: x-ray, Roentographs Invented in 1895 in Germany by a mechanical engineer Wilhelm Roentgen Called “X” –ray: X stands for an unknown ray: later determined to be accelerated electrons These rays are partly absorbed by the target (bone) and partly transmitted (soft tissue) Pictures are developed on films and represent the density of the object which the rays are directed past

Picture of Foot from 1892

X-ray Used to visualize bones Look for fractures, post surgical alignment of bones, dislocations, and signs of disease of bones

Boxers Fracture

Dislocations

Elbow Fracture

Mallet Finger Fracture and Subluxation

CT: Computed Tomography Invented by Godfray Hounsfield in England in 1972 An X-ray tube and detector are rotated around the body to be examined producing projection data of thin slices from many different views (profiles). Using computer calculation, the density distribution of the irradiated slices are reconstructed yielding 3 dimensional views or 2 dimension slices including details of soft tissue and bone Using computer calculation, the density distribution of the irradiated slices are reconstructed yielding 3 dimensional views or 2 dimension slices including details of soft tissue and bone

CT CT’s are useful to get very detailed pictures of bone, allow visualization of fractures that may not be seen on regular X-rays, and allow visualization of the soft tissues of the body. Soft tissue images are not as detailed as MRI films

CT of Head

3D CT

Spine Fracture Details on CT

MRI – Magnetic Resonance Imaging Invented in 1946 in the US by Felix Bloch and Edward Purcell, but not utilized in medicine until 1972 by Dr Paul Lauterbur, or on the human body until the 1980’s The human body is made of mostly water and fat, each of which has an unpaired proton at the nuclear level. This positively charged proton can be directionally aligned off and on by a large magnet. By alternating alignment on and off, a resonance occurs which produces a current which can be detected by the MRI. Thus the MRI is very good at detecting soft tissue (fat and water) and not as detailed at bone visualization Benefits are that radiation is not used, and very good soft tissue visualization.

MRI

Knee MRI

X-ray vs MRI

MRI of back

MRI Arthrogram Contrast Dye is injected into the joint of interest Dye can be seen in tears of cartilage, muscle, or tendon, which otherwise would be hard to detect even with MRI

Rotator Cuff Tear

MRI Arteriogram / Angiography Dye is injected into the blood vessels to better picture them Looking for abnormal vessels, blockages in vessels, blood clots, or aneurysms

Bone Scan Radiotracer (radioactive isotope that seeks bone) is injected in the blood stream. It circulates and collects in the bones in areas of high metabolism (fractures, cancer, infection) An X-ray or CT can then be used to more closely view these areas of increased uptake

Fractures Seen on Bone Scan Increased uptake is seen in bilateral calcaneous bones of the first image, and the left 4 th metatarsal in the second image These indicate stress fractures

Uses of Bone Scan Diagnosis of bone infection, known as osteomyelitis. Diagnosis of stress injuries, such as a stress fracture and shin splints. In patients with cancer, to determine whether the cancer has spread to the bone In the evaluation of unexplained bone pain.

Bone Scan Benefits In an early infection or stress fracture, the plain x-ray and CT may be completely normal. The bone scan however will show the area of injury. MRI films will also show these early findings, but MRI’s are much more expensive than bone scans Bone scan can point to the area of abnormal bone activity, but will not show details of the bone structure

Ultrasound Evaluation Used for therapy as early as the 1920’s (deep heat) Diagnostic Tool for medical ailments in the 1940’s (kidney stones) Used for orthopedic evaluations starting in late 1980’s and 1990’s Utilized more in Europe than in US Uses sound waves (like Sonar) to visualize tissues

US Uses Used commonly in pregnancy to evaluate the baby Visualize tendons (patellar, Achilles, and rotator cuff) looking for tear or tendonitis Visualize blood flow in the heart and blood vessels looking for clots or abnormal flow Echocardiograms are a form of ultrasound used to visualize the heart muscles and valves looking for defects or congenital anomalies. No radiation risk to patient

Ultrasound

US Normal and tear of supraspinatous tendon

Fluoroscopy A way to visualize motion x-rays on a video screen Allows dynamic pictures to be seen Used to visual structures while performing injections, surgery, and other procedures because live video images can be seen during the procedure. Pictures are not as detailed as x-rays so are not ideal for diagnosis but are used when x-rays are not available (Football stadium or Operating room)

Fluoroscopy

Summary X-ray: Good for initial evaluation of bones CT: Better detail of bone and soft tissue MRI: Best views of soft tissue MRI Arthrogram: Visualize dye in the joint MRI Angiogram: Visualize dye in the vessel Bone Scan: Shows area of concern in bone but doesn’t show details Ultrasound: Becoming more common for orthopedics for the United States, but still less used. Uses sonar to visualize tissues Fluoroscopy: Live video pictures of bone, used for procedures and quick look at fractures

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