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Introduction to Abdominal Radiology. Dr. LeeAnn Pack Dipl. ACVR. Abdominal Radiography. Abdominal Preparation Withhold food for 12-24 hours as needed Give enema 2-3 hours before study Exceptions Critically ill Suspect obstruction (acute abdomen). Indications. Vomiting Abdominal pain
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Introduction to Abdominal Radiology Dr. LeeAnn Pack Dipl. ACVR
Abdominal Radiography • Abdominal Preparation • Withhold food for 12-24 hours as needed • Give enema 2-3 hours before study • Exceptions • Critically ill • Suspect obstruction (acute abdomen)
Indications • Vomiting • Abdominal pain • Hematuria • Pain on defecation • Abdominal mass • Pendulous fluid filled abdomen • Many many more
Abdominal Imaging Technique • VD and lateral views • Positioning • Include from the diaphragm to the pelvic inlet • Femurs are placed perpendicular to the spine • Hind legs pulled forward for “butt shot” • Exposure is made on expiration • Collimate to decrease scatter!
Technical Factors - Abdomen • The image should be made dark enough to penetrate the liver • The abdomen has a low inherent contrast • Use lower kVp technique and higher mAs • A grid should be used to decrease scatter
Liver Spleen Kidneys Stomach Duodenum Small Intestine Cecum Colon Bladder Prostate Retroperitoneal fat Structures Normally Seen
Gall bladder Pancreas Adrenals Ovaries Uterus Ureters Lymph nodes Mesentery Vasculature Structures Not Normally Seen
Radiography of the Liver • Liver size • Normal • Increased • Decreased • Liver opacity • Increased • decreased
Normal Liver Lateral View • Caudoventral margin extends to or slightly caudal to the costal arch • Long axis of the stomach should be parallel to the ribs or perpendicular to the spine
Normal Liver VD View • Long axis of the stomach is perpendicular to the spine • Caudal margins of the liver are difficult to visualize on this view
Hepatomegaly • Caudoventral margin projects caudal to costal arch • Liver margins may be rounded • Pylorus is displaced caudodorsally and to the left • Change in long axis of stomach
Hepatomegaly • Generalized with smooth margins • Cushing’s • Fatty infiltration • Diabetes Mellitus • Hepatic lipidosis • Passive congestion • RHF • Neoplasia • LSA • Inflammation, cholestasis
Hepatomegaly • General enlargement lumpy margins • Malignant neoplasia • Nodular hyperplasia • Focal enlargement • Neoplasia • Nodular hyperplasia • Cysts, abscesses
Microhepatia • Stomach shifted cranially – especially pylorus • May be functionally normal • Portosystemic shunt • Hepatic fibrosis
Changes in Liver Opacity • Increased • Mineralization • Biliary – choleliths • Parenchymal • Parasitic cysts • Granulomatous ds • neoplasia • Decreased • Gas
Spleen • On the VD view the head of the spleen is seen • caudolateral to the stomach fundus • craniolateral to the left kidney • The position of the tail varies • More often seen on right lateral • In cats • seen “laying along left side” sometimes on VD • Not seen routinely on lateral
Splenomegaly • Normal shape, smooth margins • Drug induced • Sedatives, anx • Diffuse infiltrative process • LSA, HSA • Vascular stasis • Splenic torsion
Splenomegaly • Focal enlargement • Hematoma • Nodular hyperplasia • Neoplasia • Hemangiosarcoma • Hemangioma
Splenic Masses • May occur in the head, body or tail • Located mid abdomen, left or right • May be very large • Can cause abdominal organ displacement • Can displace stomach cranially and small intestines in various direction depending on location
Kidneys • Right located more cranial than left • Dogs = 2½-3½ * L2 on VD • Cats = 2.4-3 * L2 on VD • Size should only be evaluated on the VD view due to magnification on the lateral • IV contrast can be used if necessary
Kidneys • Increase in size • Acute inflammation • Infiltrative process • LSA • Decrease in size • Hypoplasia • Fibrosis • Renal failure • Mineralization – look a kids on both views • Focal change in shape • ACA
Stomach • Caudal to liver • Axis parallel to ribs • Change in size, shape, mineralized, rugal fold abnormal • Right vs. Left lateral (air/fluid) • Foreign bodies, outflow obstruction
Stomach • Dog – crosses from left to right • Cat – from left to midline
Small Intestine • Duodenum – fixed along right side • Jejunum and ileum – position varies • Normal width = < 3* last rib width • Contains both air and fluid • Can not determine wall thickness • Peyer’s patches, string of pearls
Cecum and Colon • Cecum • mid right abdomen • Comma shaped –may contain air • Not often seen in cats • Colon • Ascending, Transverse, Descending • Normal width = < 5 * last rib width
Urinary Bladder • Dog – caudal abdomen or pelvic • Cat – always intra-abdominal • Vary in size (empty to very distended) • Bladder wall changes can not be determined on radiographs
Urinary Bladder • Change in Opacity • Mineral • Cystic calculi • Air • Emphysematous cystitis • Iatrogenic
Prostate • Usually well visualized in intact males • Should be symmetrical with smooth margins • Enlarged if • > 50% of pelvis inlet width (VD) • >70% of sacro-pubic distance (lateral)
Prostate • Enlargement • Hypertrophy • Neoplasia • Prostatitis • Abscess • Paraprostatic cysts • Mineralization
Pancreatitis • The pancreas is not normally seen • Increased density and decreased serosal detail in the right cranial quadrant • Duodenum may be persistently distended with gas (sentinel sign) • Duodenum can be pushed to the right and pyloroduodenal angle is increased
Adrenal Glands • Seen only when enlarged or mineralized • Enlargement • Pheochromocytoma • Cortical carcinoma • Adenoma • Adrenal mineralization • Dystrophic mineralization of tumors • Mineralization of non neoplastic adrenals (cats)
Reproductive System • Uterine enlargement • Metra’s • Gravid uterus • Ovarian enlargement • Neoplasia • Enlarged retained testicle • neoplasia
Enlarged Lymph Nodes • Medial iliac (sublumbar) • Increased opacity (soft tissue) seen in caudal abdomen ventral to caudal lumbar spine • May displace colon ventrally • Mesenteric LNN rarely large enough for radiographic detection • US is best to evaluate for LAN
Enlarged Medial Iliac LN • Lymphosarcoma • Most common • Metastasis from neoplasia in the pelvis canal or further caudally • Prostate • Perineal tumors
Loss of Intra-abdominal Detail • AKA – loss of serosal surface detail • Causes: • Lack of Fat • Young • Emaciated • Peritoneal fluid • Pancreatitis, Peritonitis • Carcinomatosis
Free Intra-Peritoneal Gas • Penetration of the abdominal wall • Surgery (common) • Penetrating wounds • bullets • Bowel perforation • Obstruction • GI ulcer rupture • Large mounts may persist for days or weeks
Free Intra-Peritoneal Air • Horizontal beam radiography – to detect small volumes of air • Lateral view with dog in dorsal recumbency, cranial aspect elevated • Air collects under the diaphragm • VD view with dog in left lateral recumbency • Air up against the liver instead of fundus