[OS 206] E03-T01-Pelvis and GU Imaging_compressed

Here are study notes based on the provided text:

Imaging Methods

• X-rays use radiopaque (white) and radiolucent (dark) areas to generate images
• Tissue densities dictate whether an area is radiopaque or radiolucent
• Density order: air → fat → soft tissue → bone → metal
• Air appears lucent (black) as most X-ray beams pass through it
• Fat, muscle, solid organs, and soft tissues appear as shades of gray reflecting density and thickness
• Dense structures appear white (radiopaque) due to X-ray beam absorption bone, calcification, metal, and contrast material

Plain Kidney, Ureter, & Bladder (KUB) Film

• KUB film is a 2D image of a 3D structure
• KUB films should display the pelvis bones and extend 2 cm below, unlike abdominal films
• KUB assessments are on densities, outlines, and shadows, especially of soft tissues
• Note the location in relation to bowel and gas patterns to diagnose
• Kidneys and psoas lines appear gray, indicating solid organs and soft tissues
• Usually, the right kidney sits lower than the left
• Perirenal fat helps visualize kidney outlines
• Kidney stones can be seen in the kidney, and along the ureter and bladder

Intravenous Pyelogram (IVP)

• IVP is also known as intravenous urogram (IVU)
• IVP is a diagnostic imaging test to evaluate the urinary tract
• Standard IVP protocol:
  • Use a preliminary KUB film to assess abnormal calcifications
  • Verify contrast media has not expired and is safe
• In sequential series, contrast is injected at 1, 3, and 7-minute intervals to capture contrast phases through the urinary tract
• Views include oblique films, full bladder, and post-void films
• Fluoroscopy aids real-time imaging to check obstruction or flow
• Radiologist decides if extra views are required
• In Figure 2, abdominal compression enhances visualization (less common now)
• Entire ureters may be visible with compression
• Persistent issues indicate ureter problems
• Kidneys easily visualized due to contrast
• IVP visualizes the calyces, renal pelvis, and ureter
• Can evaluate the radio-opaque stones and collecting system

Uterus Imaging via Hysterosalpingogram (HSG)

• A catheter is inserted in the cervix with a balloon, and contrast material is injected
• Triangular uterine cavity
• Narrow fallopian tubes without mucosal irregularities
• Free contrast spill into the peritoneal cavity
• Fluoroscopic guidance is used
• Important for uterine cavity evaluation for anomalies
• May find the patency of fallopian tubes
• Used as a last resort due to invasiveness

Ultrasound Imaging

• Hyperechoic (bright) vs. hypoechoic (dark)
• Has 3D imaging and good resolution
• Uses high-frequency sound waves
• Transducer (probe) converts electrical energy into high-frequency sound waves(ultrasound)
• Probe transmits waves into body
• Tissues reflect back as echoes
• Transducer detects sound energy echoes from tissues
• Tissue contrast relies on sound reflection
• Commonly used screening tool for kidneys and renal tract
• Color Doppler ultrasound assesses tumor vascularity and extension of renal tumors into the venous system
• Pros: No ionizing radiation
• Primary choice for pediatric and obstetric patients
• Cons: Operator-dependent; lesions might be missed, high skill is needed

Ultrasound Transducers

• Pulses range from 1 to 17 MHz
• High frequency (10-17 MHz) gives greatest resolution, but has limited penetration, and can image only superficial structures
• High frequency may be higher due to tech advances
• Low frequency (1-3.5 MHz) gives better penetration but has poorer resolution

Types of Probes for Ultrasound Imaging

• Endocavitary: high-frequency, transrectal and transvaginal studies
• Linear: high-frequency, shallow like Dolly Parton view for tight spaces; can be for pediatric and teen patients due to bodies because they are thin.
• Convex: low-frequency, obstetric and pelvic studies, and assessments involving the abdomen and pregnancy.

Ultrasound Image Production

• Image production is based on capabilities to absorb, scatter, and reflect sound waves from the tissues
• Sound energy is heavily absorbed at soft tissue and bone interfaces, thus, an acoustic shadow forms disrupting visualization of the bone surface
• Sound energy nearly reflects at soft tissue and gas interfaces; visualization is not good
• Pelvic organs are examined through the urine-filled bladder (a sonographic window)
  • Appears black in the image as little sound energy is absorbed
  • Displaces gas-filled bowel out of pelvis
  • Results in posterior acoustic enhancement for easily visualized structures
• Intraluminal masses, calculi, bladder wall thickness, and bladder emptying can be assessed

Computed Tomography (CT) Scan

• Hyperdense (brighter) vs. hypodense (darker)
• Densities are same system as X-rays but has detectors and 3D visualization
• Provides superior 3D images with spatial relationship
• Shows bone fragments in pelvic fractures
• Sensitive to locate kidney stones in the ureter
  • CT Stonogram is the best study
• Has better visualization for bones than soft tissues
• Can be performed with/without contrast
• Cross-sectional slices are produced
• Contains more detailed information than conventional X-rays
• The higher the slice number on the faster the CT machine for image acquisition
• Viewed in sequential order, examining each slice with reference to slices above and below to interpret anatomy and pathology
• Images exist in axial plane then are reconstructed in coronal and sagitall planes

Magnetic Resonance Imaging (MRI)

• Hyperintense (brighter) vs. hypointense (darker)
• Uses strong magnetic and radio waves to create detailed 3D images
• Protons in the body emit radio wave energy due to the body being placed within a strong magnetic field
  • Tissues absorb/ release the radio wave energies with varying rate
• Advantage is no ionizing radiation
  • Using radiation is problematic for Pediatrics
• Useful for structures, even w/o contrast:
  • Soft tissue, ligaments, cartilage
  • Organs: Kidney, Uterus, Prostate
• Detailed history is done to check for contraindications like metal inside the body, bullets, shrapnel and medical devices
• This is completed because the powerful magnetic field in the MR system will pull out any magnetic objects from the patient
• Longer to acquire images than with a CT as an MRI can have many contrasts
• Visualize it through the axial, coronal, and sagittal planes
  • axial plane then software is used to reconstruct it into other planes
• Run with or without contrast
• More costly in comparison to the other modalities

Advantages and Disadvantages of MRI

• Advantages include: outstanding soft tissue contrast resolution, provides images in any anatomic plane with the absence of ionizing radiation
• Disadvantages include: demonstration of dense bone detail, long imaging times for many pulse sequences, and higher costs due to availability

Kidney Imaging: Plain Abdomen vs. Plain KUB film

• Hemidiaphragm - In abdomen film HAS TO BE SEEN, but KUB film hemidiaphragm MAY be partially cut off or not completely seen depending on location.
• Pelvis - Abdomen film MAY BE PARTIALLY CUT OFF, as long as the structure is viewable if needed, but in KUB film it HAS TO BE SEEN & must include the inferior pubic rami & 2 cm inferior to it
• Bowel Preparation - not needed in Abdomen film because its primarily looking at the other organs (liver, spleen etc)

Kidney Imaging: X-Ray

• Used as an initial study
• Problem - there can be a case in what if the organ isn't present
  • How would it look?
    • Based on landmarks, there may be a problem
• Modality of this method: X-ray → Ultrasound → CT scan/MRI

Kidney Imaging: Ultrasound- General

• Uses solid organs to locate organs
• Air in the abdomen would mask the structures behind it

Kidney Imaging: Multi-Detector Contrast CT (MDCT) Stages

• Precontrast Scans
  • Plain contrast studies: Like IVP,
  • Used to assess urinary stones and calcifications
• Arterial Phase
  • Contrast scans through kidneys -uses those with contrast
  • Shows the enhancement of renal tumors when starting out (early)
• Nephrogram phase
  • Contrast after being shown approximately 2 minutes
  • Equally homogenous lighting up of the kidneys (cortex)
• Pyelogram phase
  • Contrast after being shown approximately 3-5 minutes
  • Filling of the collecting system & ureters

Ureter Imaging: IVP

• Usual placement of Ureter DOESN'T go beyond the transverse processes laterally (think where the spinous/transverse processes are)
• Calyces: Red arrow - shape: cup shape; will look shallower or bulged when dilated
• Renal Pelvus Labeled as P
• Point crossing the UPJ, Point crossing the pelvic rim, and Point crossing the ureteropelvic junction

Urinary Bladder Imaging

• Posterior to the symphysis pubis
• Hollow muscular vesicle that stores Urine, even if only for short time
• Located posteroanterior to the uterus (Females)/ superoanterior to the prostate (Males)
• Shape of the bladder matters bc in adults & infants, etc they'll have variations
  • When you're an ADULT
    • Bladder is full = looks like an ovoid/egg & rises extraperitoneal, which means it goes into the abdomen and into the retroperitoneal cavity
    • Bladder is empty = Pyramidal in shape (more like an open cone); It'll still be within the pelvis
• Structures in the posterior:
  • Is it a male patient then we expect/ will see their prostate
  • if they're a female, then we expect / will see their vagina

Urinary Bladder Imaging: Ultrasound

• When bladder is full - echogenic walls shouldn't exceed 4-5 mm in thickness
• Normal Fluids = Anechoic
• Walls are thin and Uniformly thick in general
• Sandy texture - there are blood or sediments (not normal & more likely to be pathology in the image)
• NOTE: in ultrasound images you DON'T see any air or bone bc they won't/ don't show

Bony Pelvis Imaging

• Bones of the Pelvis: ilium, Pubis, and Ischium
• Know about the Pelvic Inlet which are the Sacral promontory and superior part of the pubic bone - it separates the True pelvis below and False pelvis above

Pelvic CT- Female vs Male

• Female: Lighter weight and Thinner
• Male: Heavier weight and Thicker
• Shape of the Pelvis to differentiate
  • Female: Round, Oval, (for child'bearing) -Male: Looks like what the medical textbook version of a heart is shaped like- it has a sharp v like shape at the top

Uterus Imaging

• Prepubertal: cigar-shaped
• Postpubertal: pear-shaped
• Maximum normal uterine dimensions: 9x6x4cm (L x W x AP)
• Description: anteverted, anteflexed, retroverted, retroflexed

Ultrasound of Ovary

• Premenopausal: Bigger, lots of follicles
• Postmenopausal: Smaller, no follicles

Testis and Epididymis Imaging

• Testis: ~3.5 cm covered by tunica albuginea dense fibrous capsule
• Epididymis: Head, body, tail
  • Head is rests along the anterior and superior, is 7.8mm
  • Body and tail thickness decreases to 1-2mm

Ultrasound of testis, gen.

• Color doppler is initial modality for testes
• Epidimycal is at sagittal part:
• Absence of radiation

Prostate

• Peripheral gland slightly more hyperechoic than central/inner gland.

Seminal Vesicle

• Appears convoluted.
• Composed of lobulated sacs.
• Lie transverse behind the bladder
• Normal seminal vesicle looks like on a stache on images..

Study notes covering imaging methods like X-rays, focusing on radiopaque and radiolucent areas. Includes details on visualizing densities and structures in a Plain Kidney, Ureter, & Bladder (KUB) Film.