ct abdomen and pelvis abdomen . patient preparation oral contrast material to opacity the...

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  • Abdomen and pelvis

    CT ANATOMY

    MAMDOUH MAHFOUZ MD

    mamdouh.m5@gmail.com

    www.ssregypt.com

  •  Indications

     Patient preparation

     Patient position

     Scanogram

    • To assess equivocal imaging findings • Staging of hepatic neoplasms • Metastatic workup of primary malignancies • Diagnosis of abdominal masses • Assessment of biliary problems • Diagnosis of vascular lesions • Assessment of suspected post-traumatic complications

    CT

    ABDOMEN

  • Patient preparation

     Oral contrast material to opacity the gastrointestinal tract [gastrographin 38% diluted by water to 4%]

    - Timing?

     Not indicated in  Acute abdominal trauma

     Acute renal colic

     Dehydrated patients

  •  Indications

     Patient preparation

     Patient position

     Scanogram

    CT

    ABDOMEN

    No required preparation unless the patient is going to be sedated

    or injected with contrast material

    FASTING FOR 4 - 6 HOURS

  •  Scanogram Frontal

     10mmscan intervals [ 5mm sections are necessary for pancreas, suprarenal glands, urinary bladder]

     Window setting  Soft tissue window

     Lung window [scans at the lung bases]

     Bone window [lesions in the spine or pelvic bones]

  • Patient preparation

    IV contrast material [urographin,…] 60ml

    • Fasting 4-6 hours ?! • Pre contrast scans [ liver, kidney, urinary bladder] • Triphasic scan for liver [ arterial, portal, delayed]

    Detailed examination of the Superior Mesenteric Artery and Celiac Artery. Scan time = 9.4 seconds. 1mm slice thickness

  • Value of precontrast study

  • Hyper vascular deposits

    Arterial phase

  • Value of arterial phase

    images in hepatic

    lesion detection

  • Male

    pelvis

  • Female

    pelvis

  • LS

    MS

    AS

    PS

  • Hepatic segmental anatomy

  • LS MS

    AS

    PS

  • LS MS

    AS

    PS

  • No focal lesions

    ?!!

    Contrast enhanced CT

    or MRI

  • ?!

  • Diffuse hepatic diseases?!!

    Fatty liver

    Cirrhosis

    Storage diseases

  • No dilated biliary radicals ?!!

  • In tra

    he pa

    tic bi

    le du

    ct di

    lat ati

    on

  • Vessels in the

    liver ?!!  Hepatic artery

     Hepatic veins

     Portal veins

  • CT Portography

  • CT Portal venography in a

    56Y Male with portal vein

    thrombosis

    CT Portal venography

    showing portal

    hypertension with GE

    varicosities

  • Normal variants

  • Agenesis of the anterior segment of the right hepatic lobe

  • Porta-hepatis

    Hepatic artery

    Portal vein

    cbd

  • Pancreas

    Anatomy  Anterior pararenal space,

    retroperitonium  Head (3cm) neck, body (2.5cm)

    and tail (2cm)  Pancreatic density is similar to

    unopacified bowel and vessels  5mm sections  Pancreas does not have a firm

    capsule

  • Pancreatic atrophy with fatty infiltration, age related

  • Pancreatitis, acute Pancreas, normal

  • Pancreatic

    anatomy

  • Pancreatic head, superior mesenteric artery and vein

  • Suprarenal glands

  • F 35Y

  • QUIZ

    CASES

    1 2

    3

  • MRI Coil selection

    Body coil

    Phased – array multicoils

    • Increases signal/ noise ratio

    • Allows smaller field of view

    • High cost

    • Very high signal of subcutaneous fat

  • Examination protocol

    • Coronal localizer

    • Axial T1 and T2 WIs

    • Coronal T1 and T2 WIs

    • Axial T2 fat suppression

    • Dynamic post contrast axial T1 WIs

    [Arterial , portal and delayed phases with or without fat suppression ]

  •  Normal liver is of similar or higher signal to muscles [T1]  Normal liver shows intermediate signal [T2]  Spleen shows increased signal compared to the liver [T2]

  • MRI normal spleen

  • Multiple Angiomyolipomas T1, T1 Fat sat, T1 fat sat +c

  • MR advantages

     MR is more sensitive in detection

    and characterization of hepatic hemangioma

    [high signal on heavily T2 weighted sequences]

     MR can differentiate focal fatty changes from deposits

     In diffuse fatty infiltration hypo dense deposits may

    be masked by the hypo dense background of fatty

    liver on CT .On MR the background is relatively high

    signal in T1 WIs while deposits are of low signal,

    so increases the difference

     MR is sensitive for detection of hemorrhage

    Hemangio

    mas

    demonstrat

    ed by

    heavily

    weighted

    T2 MRI

  • Normal renal

    MRI.

  • T

    1

    T1+

    C T

    2

    Normal renal MRI.

    [Fat suppression]

  • T1 weighted images

     Normal liver is of similar or higher signal to muscles

    • T1 spin echo sequences

    • T1 breath hold gradient echo images SPGR/ FLASH

    Short TE 5 msec TR> 100mesc

    Flip angle 80-90 degrees

    Magnetization prepared T1 weighted GRE images [STIR]

    very short TR < 10mesc

    flip angle 40 degrees

    Inversion time 500

  • T2 weighted images

     Normal liver shows intermediate signal

     Spleen shows increased signal compared to the liver

    • Conventional T2 spin echo sequences

    • T2 with rapid acquisition and relaxtion enhancement FSE Difference from T2 SE

    • Higher signal intensity of fat on FSE

    •  magnetic susceptibility artifacts of metals on FSE

    • ↑ magnetization transfer effect in FSE→ signal of solid lesions

  • MRI Fat suppression

    Advantages • Decrease motion artifacts

    • Improve signal/ noise and

    contrast/ noise ratios of focal hepatic lesions

  • نستغفرك و نتوب اليك @نشهد ان ال اله اال انت @سبحانك الهم و بحمدك

    Thank you

  • Diaphragmatic attachment of the liver

  • Malignant Colonic polyp

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