INTRO-CT, XR, MRI Flashcards
What has replaced hard copy images, allow for instanct access?
PACs- picture archiving and communication system
When analyzing xray what is first step?
- Verify name, date
- Study- body part, correct side. Pt R is my L.
OLD films first on L to New- read L to R
Good for- bones, lungs, FB, Air filled organs
AVOID- detail, solid organs, Brain, vasculature
What components are needed to be able to identify structures on Xray?
- Radiolucent- dark or Radiopaque
a. air- dark, less dense, radiolucent
b. fat- dark grey
c. soft tissue, blood, liver- light grey
d. bone- cream
e. metal- white, more dense, radiopaque - Density- inc opaqueness
- Thickness- inc opaqueness
Before an Xray is taken what factors must be considered by the tech?
HCP should know position
1. NO movement
- Magnification-
a. objects bigger if beam close and IF Pt far from cassette surface - Distortion-
a. lordotic- object distorted if not perpendicular. Pt in bed, angled. heart base BIG
b. High clavicle means Lordotic** - NEVER judge cardiomegally from CXR unless it a PA
Describe the planes that can be taken in XR.
- Frontal/Coronal- PA, ventral to dorsal
- PA- beam posterior to Pt, Pt close to cassette ***
- Obligue
- Cephal-caudal- bird eye, AXIAL
- Sagital- L and R
- Transverse
What is the ideal systematic approach to read XR?
1. Name, date, study 2a- OBvious ABNormality 2b. Adequate- RIPMA 3. Top to bottom, then Pt R-L 4. Bone, soft tissue, empty spaces 5. Free stuff, FB 6. DONT STOP at big abnormality or when you find what looking for.
How do you locate a foreign body with in the chest?
ALWAYS have a orthogonal view
PA and Lateral
What is computed tomography?
Contrast or w/o
Series of Xray in spiral form
Slice in 3planes- Frontal/coronal, Sagital, Axial
PT R is my L
What are contraindications for contrast?
Barium MC- white iNC density, INC attenuation
NO contrast for KIDNEY stone**, which is white. will miss if contrast used.
AVOID- CR >1.5
3 Cs- CT, contrast, Cr
Allergy
Metformin - d/c 24h b4 test
What subtract stuff not need in CT?
3-D orientation
Pt is c/c of CP with rest, PMH of a pacemaker and Stainless steel THR?
AVOID MRI for the following no metal. Stainless steel and titanium ok Claustrophobic Long Loud
What are HCP allowed to interpret w/o a radiologist?
CXR
cheap, fast, portable, FB
What are MC use for XRay and CXR?
CXR-Resp sx, CP, PNA Upper GI- obstruction Trauma Face and spine Air fluid level Extremities FX
CONS- radiation, very low, poor detail, less precise, poor solid organs, brain, vessels
What is ideal use for CT?
Brain, head- seizure, CVA, injury
Chest- tumors, effusion, infx, PE
ABD- inf obstruction, cancer
Extremities
What provides great detail, 3D, reformat. BUT radiation and concern w/ renal fx, cost not portable?
CT
NOT good for subtle CVA
Cerebellum or Vertebrobasilar
What do terms mean for CTs?
HIGH/HYPERAttenuation
LOW/HYPOAttenuation
HIGH/HYPERAttenuation WHITE-dense
LOW/HYPOAttenuation BLACK
Calculated hounsield unit
This imaging is good for Lig, tendons, spinal cord, brainstem, Intracranial, MS, encephalitis, FX, osteomylitis, Tumor, necrorsis, Stones?
MRI
Which film should be ordered first for CVA?
CT w/o contrast
Which film should be ordered for meningitis?
MRI
What do low and high signal in T1 and T2 mean in MRI?
T1- fluid BLACK LOW signal, fat WHITE HIGH signal
T2- fluid WHITE HIGH signal, fat black LOW signal
Contrast still white
What uses high frequency sound waves?
US FAST trauma Cardia, Lung, ABd-OB Aorta Biliary DVT** Kidney bladder-stones IV, Cath, Line, intub. Absess, FB
What are major disadvantage of US?
Operator dependent
PRos- avail, portable, safe, color doppler, Cheap
What are terms for US?
Echo echogenic- bright, structure Acoustic shadow- from structure like Ca stones Anechoic-dark Hyperecho- white Hypoehco- grey
What is used to diagnosis stage cancers?
Nuclear scans- picks up tracer PET Bone Scan Thyroid scintography V/Q PE- rare HIDA gallblader Cardiac perfusion
High Low uptake-
What is contreversial about mammography?
Radiation
Low dose xray, US, MRI
Screen and diagnositc.
What is used to monitor path of needles, fluid thru tubes: GI swallowing, Angiograms, cystourethrogram, biopsis, FB?
Fluroscopy
Angiography**
Depends on modality and contrast