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Biomedical Diagnostics Two. Lesson One- Basics. Gamma ray emission from within the body. x-ray Transmission through the body. Basic Imaging Principles. Nuclear magnetic resonance induction. Ultrasound echoes. Basic Imaging Principles. What does the human body look like on the inside?
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Biomedical Diagnostics Two Lesson One- Basics
Gamma ray emission from within the body x-ray Transmission through the body Basic Imaging Principles Nuclear magnetic resonance induction Ultrasound echoes
Basic Imaging Principles What does the human body look like on the inside? Invasive Techniques: • Operation • Endoscope Noninvasive Techniques: • Magnetic Resonance Imaging (MRI) • Ultrasound Imaging • x-ray • Computed Tomography (CT) • Nuclear Medicine • Functional Magnetic Resonance Imaging (fMRI) • Positron Emission Tomography (PET)
Basic Imaging Principles What do Images look like, and why? Image reconstruction: the process of creating an image from measurement of signals. Image quality determined by: • Portray of the true spatial distribution of the physical parameters. • Resolution • Noise • Contrast • Geometric Distortion • Artifacts
Projection Images: The creation of a two-dimensional image “shadow” of the three dimensional body. X-ray are transmitted through a patient, creating a radiograph.
The three standard orientations of slice (or tomographic) images Axial, Transaxial, Transverse Coronal Frontal Sagittal Oblique Slice: an orientation not corresponding to one of the Standard slice orientation.
Positron Emission Tomography Magnetic Resonance Imaging Computed Tomography
Computed Tomography (CT-scan) The x-rays are collimated (restricted in their geometric spread) to travel within an approximate 2-D “Fan beam” Type of CT scan: single-slice CT, helical CT, multislice CT
Nuclear Medicine Imaging of gamma rays emitted by radionuclides substance bounded to biochemically active drugs. Example iodine to study thyroid function.
Ultrasound Imaging Uses electric-to-acoustic transducers to generate repetitive bursts of high-frequency sound. Time-of-return: give information about location Intensity: give information about the strength of a reflector
Magnetic Resonance Imaging (MRI) - Hydrogen nucleus align itself with an external Magnetic field - Radio frequency pulse cause hydrogen atoms to tip a way from the direction of the external magnetic field. - When excitation pulse end, hydrogen nucleus realign itself with the magnetic field and realize a radio-frequency.
Ultrasonography Obstetrics
CRL: Crown Rump Length • Earliest detection at 4-5 weeks
11-12 week fetus shows division of hemispheres and choroid plexus
Study of intracranial features including the cerebellum and corpus callosum.
Diagnosis of fetal malformation. • Hydrocephalus • Anencephaly • Myelomeningocoele • Achondroplasia, • Spina bifida, • Cleft lips/ palate and • Congenital cardiac abnormalities
placenta previa • diabetes, • fetal hydrops, • Rh isoimmunization and • severe intrauterine growth retardation
HISTORY:71 year old woman recently noticed a left breast lump. DIAGNOSIS:Intracystic papillary carcinoma HISTORY:71 year old woman recently noticed a left breast lump. DIAGNOSIS:Intracystic papillary carcinoma
Gallbladder US • The gallbladder demonstrates tiny gallstones. There was mild tenderness over the gallbladder. However, there is no evidence of wall thickening or pericholecystic fluid. There was no ultrasound evidence of acute cholecystitis.
Gall Bladder US • Stone within the distal portion of the common bile duct.
Roundworm in the liver • A typical double-line echo pattern representing an Ascaris worm extends from the right lobe into the porta hepatis