Abdome Agudo

Prévia do material em texto

26/02/2016 
1 
Abdome Agudo 
ABDOME AGUDO 
Causas mais comuns para abdome 
agudo 
 
Padrão normal de gás abdominal 
• Predominantemente, ar deglutido; 
• Níveis hidroaéreos em pacientes normais 
predominantemente no estômago, intestino delgado, 
mas nunca no cólon distal à flexura direita do cólon. 
• Níveis no intestino delgado não devem exceder 2,5 cm 
de comprimento. Múltiplas coleções de gás pequenas e 
aleatórias por todo o abdome. (pacientes que 
deglutem ar e ingerem bebidas gaseificadas possuem 
aumento no gás intestinal). Ou seja, são três a quatro 
alças do intestino delgado de formas variáveis, 
medindo menos de 2,5 a 3 cm de diâmetro. O cólon 
normal contém algum gás e material fecal, diâmetro 
variando de 3 a 8 cm, enquanto o ceco apresenta o 
maior diâmetro. 
Normal Bowel Gas Pattern. Supine 
radiograph shows the normal 
distribution of 
gas in the stomach (large arrow) 
and the duodenum (small arrow). 
The normal mottled pattern of 
stool is seen in the distribution of 
the right colon (arrowhead). A few 
gas collections within small bowel 
(curved arrow) are seen in the 
pelvis. 
Intestino dilatado 
• Intestino delgado: diâmetro maior que 2,5 a 3 
cm; localização mais central, possui pregas 
circulares, que atravessam todo o diâmetro da 
luz; 
• Cólon: mais de 5 cm de diâmetro; mais 
periférico, possui haustros que só se 
estendem em parte da luz; contém material 
fecal com aspecto mosqueado; 
• Ceco: diâmetro maior que 8 cm; 
26/02/2016 
2 
Íleo adinâmico 
• Segmento com peristalse nula ou reduzida, 
fazendo que o conteúdo intestinal fique 
parado. 
• Distensão simétrica e predominantemente 
gasosa do intestino 
Adynamic ileus 
lleus. Postoperative gaseous 
distension of both small and 
large bowel. 
Note the midline surgical staples 
and the positive Rigler’s sign 
(arrows). 
Alça sentinela 
• Segmento sem peristalse (ou reduzida), 
paralisado e dilatado por estar situado próximo a 
um órgão intra-abdominal inflamado. 
• Quadrante superior direito: colecistite aguda, 
hepatite, pielonefrite. 
• Quadrante superior esquerdo: pancreatite, 
pielonefrite ou lesão esplênica. 
• Quadrantes inferiores: diverticulite, apendicite, 
salpingite, cistite ou doença de Crohn. 
Sentinel Loop. Daily serial radiographs of this patient demonstrated a persistent 
loop of dilated small bowel (arrow) in the same location. This sentinel loop was 
caused by acute pancreatitis. Normal gas pattern is present in the right colon 
(arrowhead). The abdomen is otherwise 
devoid of intestinal gas. 
Bowel obstruction 
• Small-bowel obstruction 
– The causes of SBO can be divided into 
intraluminal, luminal and extrinsic causes: 
• Intraluminal: foreign body, bezoar, parasites, gallstones, 
food bolus. 
• Luminal: atresia, inflammatory stricture (Crohn’s 
disease, TB), haematoma, tumour. 
• Extrinsic: adhesions, congenital bands, malrotation, 
herniae, intussusception. 
26/02/2016 
3 
Radiological features 
• Dilated loops of small bowel (>3 cm) disproportionate to 
more distal small bowel or colon; 
• Small bowel air–fluid levels that exceed 2.5 cm in width; 
• Air–fluid levels at differing heights (>5 mm) within the 
same loop (“dynamic air–fluid levels”) (strong evidence of 
obstruction); 
• Two or more air–fluid levels; 
• Small bubbles of gas trapped between folds in dilated, 
fluid-filled loops producing the “string of pearls” sign, a row 
of small gas bubbles oriented horizontally or obliquely 
across the abdomen. 
• The level of obstruction is determined by dilated loops 
above the obstruction and normal or empty loops below 
the obstruction. 
Strangulation obstruction 
• Strangulation obstruction is associated with 
changes in the bowel wall and mesentery caused 
by impairment of blood supply. 
• CT findings are: 
– (1) circumferential wall thickening (>3 mm); 
– (2) edema of the bowel wall (target or halo 
appearance of lucency in the bowel wall); 
– (3) lack of enhancement of the bowel wall (most 
specific sign); 
– (4) haziness or obliteration of the mesenteric vessels; 
– (5) infiltration of the mesentery with fluid or 
hemorrhage. 
Closed-loop obstruction 
• Closed-loop obstruction is indicated by the 
following CT signs: 
• (1) radial distribution of dilated small bowel with 
mesenteric vessels converging toward a focus of 
torsion; 
• (2) U-shaped or C-shaped dilated small bowel 
loop; 
• (3) “beak”• sign at the site of torsion seen as 
fusiform tapering of a dilated bowel loop; 
• (4) “whorl” sign (spiral) of tightly twisted 
mesentery seen with volvulus. 
Small Bowel Obstruction—
Conventional Radiograph. 
Erect radiograph of the 
abdomen reveals dilated air-
filled loops of small bowel 
containing air-fluid levels at 
different 
heights within the same loop 
(arrows). Note the valvulae 
conniventes (arrowhead) that 
extend across 
the entire diameter of the 
bowel lumen. The small bowel 
obstruction was due to 
adhesions 
Classic small bowel obstruction: valvulae 
conniventes clearly demonstrated. 
Note that the hernial orifices have not been 
included on the radiograph. 
Small Bowel 
Obstruction—CT. Coronal 
plane-reconstructed CT 
demonstrates 
abrupt transition (arrow) 
between dilated and 
nondilated small bowel in 
this patient with radiation 
enteritis causing small 
bowel obstruction. The 
small bowel feces sign 
(arrowhead) is also 
evident. 
26/02/2016 
4 
Small bowel obstruction 
Acute small-bowel obstruction. 
Multiple dilated loops of small 
bowel within the central abdomen. 
Acute small-bowel obstruction 
secondary to an obstructed 
right inguinal hernia (arrowhead). 
Small-bowel obstruction secondary to a right femoral hernia. The 
transition point is in the right femoral canal (arrow) with multiple dilated 
proximal loops. 
Small-bowel obstruction secondary to adhesions. Note the transition 
point (arrowhead) in the RIF, with multiple dilated and fluid-filled proximal 
small-bowel loops. Small-bowel obstruction. Dilated fluid-filled small-bowel loops 
secondary to a closed loop obstruction (arrow). 
26/02/2016 
5 
Large bowel obstruction 
• • This may be diagnostic. The distended colon lies 
around the periphery of the abdomen and is 
distinguished from small bowel by haustral markings 
that do not traverse the entire bowel lumen. 
• • Bowel distal to the obstruction is collapsed and the 
rectum does not contain gas. 
• • If there is a tumour of the caecum and ascending 
colon, with an incompetent ileocaecal valve, only the 
small bowel may be distended. 
• • The typical appearance of a caecal or sigmoid 
volvulus may be apparent (this is covered elsewhere). 
• • Intramural or free intra-abdominal gas may be seen. 
Large-bowel obstruction. 
Gaseous distension of the 
colon, with 
relative paucity of air beyond 
the mid descending colon. 
Large-bowel obstruction 
(same patient as above). 
Contrast enema 
demonstrates an obstructing 
lesion (arrow) within the 
mid descending colon. 
Large-bowel obstruction secondary 
to an obstructing sigmoid 
carcinoma. 
Note the extensive colonic 
distension up to, and including, the 
sigmoid colon. 
Large-bowel obstruction secondary to an obstructing sigmoid 
carcinoma, with extensive colonic dilatation and gross faecal loading. 
Pseudo-obstruction 
• • This does not differentiate pseudo-obstruction 
from mechanical obstruction but will 
demonstrate distended loops of large bowel. 
• • Serial films may be useful to document the 
clinical course and monitor the colonic diameter. 
 
• CT: further imaging is not usually necessary 
unless a mechanical obstruction has not yet been 
excluded. 
26/02/2016 
6 
Pseudo-obstruction. 
Significantgaseous 
distension of the ascending 
and 
transverse colon. In contrast 
with mechanical large-
bowel obstruction, no 
obstructing lesion can be 
identified to account for the 
appearances. 
BOWEL ISCHEMIA AND INFARCTION 
• Circumferential or nodular thickening (>5 mm) of the bowel wall 
with infiltration of low-density edema or high-density blood, 
resulting from mucosal injury; 
• “Thumbprinting” resulting from this nodular infiltration of the 
bowel wall; 
• Dilatation of the bowel lumen (>3 cm for small bowel; >5 cm for 
colon; >8 cm for cecum); 
• Pneumatosis intestinalis; 
• Edema or hemorrhage into the mesentery; 
• Engorged mesenteric vessels; 
• Thrombosis of mesenteric arteries or veins; 
• Poor enhancement of the bowel wall along its mesenteric border, 
which is evidence of ischemia; 
• Poor or absent mucosal enhancement with thinning of the bowel 
wall, which is evidence of bowel infarction; 
• Ascites, which is commonly present 
Pneumatosis intestinalis 
• Presence of gas within the bowel wall 
• Bowel necrosis, usually associated with other 
radiographic and clinical signs of bowel ischemia; 
• Mucosal disruption caused by ulcers, mucosal 
biopsies, trauma, enteric tubes, or inflammatory 
bowel disease; 
• Increased mucosal permeability related to 
immunosuppression in AIDS, organ 
transplantation, or chemotherapy; and 
• Pulmonary disease resulting in alveolar 
disruption and dissection of air along interstitial 
pathways to the bowel wall. 
Pneumatosis Intestinalis. A. 
Digital radiograph scout scan 
from CT reveals 
pneumatosis of the colon as 
dark linear streaks of air 
(arrowheads) in the colon 
wall. Both small and 
large bowels are markedly 
dilated. 
B. CT image of the same patient viewed with lung windows confirms the presence of air in 
the colon wall (arrowheads). The small bowel (SB) is dilated. At surgery, both small and large 
bowels were infracted. The patient expired. 
Abdominal trauma 
• Hemoperitoneum—acute blood within the peritoneal cavity measuring 30 to 45 H; 
• Sentinel clot—a focal collection of clotted blood (>60 H) that may be seen in the 
peritoneal cavity adjacent to an injured organ; 
• Active bleeding, as evidenced by extravasated contrast (85 to 370 H) seen during 
arterial phase of scanning with MDCT; 
• Free air within the peritoneal cavity, which is an insensitive sign of bowel injury 
provided that diagnostic peritoneal lavage has not been performed; 
• Free contrast within the peritoneal cavity, which may result from oral contrast 
leaking from injured bowel or IV contrast leaking from a ruptured bladder; 
• Subcapsular hematomas, which appear as crescent-shaped collections confined by 
the capsule of the injured organ; 
• Intraparenchymal hematomas, which appear as irregularly shaped low-density 
areas within a contrast-enhanced solid organ; 
• Lacerations, which appear as jagged linear defects defined by lower-density blood 
within a contrast-enhanced injured organ; 
• Absence of organ enhancement, which reflects damage to the organ’s arterial 
supply; 
• Infarctions, which are seen as zones of decreased contrast enhancement that 
extend to the capsule of a solid organ. 
26/02/2016 
7 
Hemoperitoneum and 
Sentinel Clot. CT scan 
shows high-
attenuation fluid in the 
peritoneal recesses 
indicating 
hemoperitoneum (H). 
A sentinel clot ( arrow) 
stands out as a high 
attenuation 
collection within the 
lower-attenuation 
liquid blood. The 
location of the clot 
suggests 
injury to the liver (L). A 
laceration of the left 
lobe of the liver, not 
evident on the CT, was 
found at 
surgery. 
Active Hemorrhage-–Liver Laceration. CT shows a jagged laceration 
(arrowheads) of the liver (L) filled with blood. A focus of continuing active hemorrhage ( 
arrow) is seen as an ill-defined collection of high-attenuation contrast agent. 
Hemoperitoneum (H) is evident in the peritoneal recesses. Sp, spleen; St, stomach. 
Renal Infarction. 
Postcontrast CT reveals a 
lack of enhancement 
(arrow) of the 
posterior portion of the 
left kidney (LK), which 
occurred as a result of an 
intimal tear and 
thrombosis 
of a branch renal artery 
occurring during a motor 
vehicle collision. Note that 
the defect in 
enhancement extends to 
the capsule of the kidney 
indicating acute renal 
vascular injury. 
Rupture of the spleen. Rupture of the anterior half of the spleen 
caused by blunt trauma in falling from a horse. Haemorrhage is seen 
within the splenic bed (arrow) along with free blood around the liver 
(arrowhead). 
Splenic laceration (arrow). 
Large liver laceration (arrow). 
26/02/2016 
8 
Liver haematoma. Large haematoma within the superior aspect of the 
right lobe of liver (arrowhead) with an additional subcapsular haematoma 
(asterisk). 
Closed blunt right renal trauma. 
There is asymmetry between the 
two 
renal outlines, with distortion of the 
left pelvicalyceal system and left 
renal 
outline. In addition there is a 
scoliosis of the thoracolumbar 
spine, concave 
towards the injured side, and a 
localised ileus of the splenic flexure. 
Normal 
contrast excretion seen from the 
right kidney. 
Kidney trauma. Multiple fractures of the right kidney (arrowheads) 
caused by blunt trauma from a kick by a horse. Extensive surrounding 
perinephric haemorrhage. 
Pancreatic trauma. Laceration of the pancreas within the proximal 
body (arrowheads). 
Duodenal haematoma. Diffuse thickening of the third part of 
duodenum secondary to a post-traumatic duodenal haematoma 
(arrowheads). 
Extraperitoneal bladder 
rupture following a fall. 
Cystogram 
demonstrates extravasation of 
contrast in to the right 
hemipelvis, tracking 
along the peritoneal reflection 
(arrow). Note the fracture of 
the right 
superior pubic ramus 
(arrowhead). 
26/02/2016 
9 
Large left pelvic haematoma (asterisk) secondary to a pelvic fracture 
(arrowhead). Cystogram reveals that the bladder is elevated and compressed 
to the right, producing a so-called ‘tear drop’ shape to the bladder. 
Extraperitoneal bladder perforation following a transurethral resection of 
a bladder tumour. This CT cystogram clearly demonstrates contrast 
extravasation into the perivesical soft tissues (arrows). Note the presence of 
several bladder diverticula and a Foley balloon catheter within the bladder (B). 
Lymphadenopathy 
• Lymphadenopathy can have numerous causes, 
which can be broadly divided into neoplastic, 
infective and inflammatory conditions: 
– neoplastic: lymphoma, leukaemia, metastatic 
cancer. 
– infective: TB, bacterial, viral, fungal. 
– inflammatory and miscellaneous: Castleman’s 
disease, amyloid, sarcoid, mesenteric 
lymphadenitis. 
Radiological features 
• AXR: may detect calcification within lymph nodes but overall is not helpful. 
• CT: 
– CT is particularly useful in assessing the extent of lymphadenopathy, 
identifying an underlying cause and any complications, for example 
hydronephrosis secondary to enlarged lymph nodes. 
– It is also useful as a method of following up patients known to have 
lymphadenopathy, after treatment. 
– IV contrast is routinely given to help to differentiate lymph nodes from 
adjacent vessels and oral contrast or water to outline smallbowel loops. 
– As on US, benign nodes may also demonstrate a fatty hilum and characteristic 
oval shape. 
– Enlarged lymph nodes can be characterised further by their appearance. 
– For example, tuberculous nodes typically have a low-density necrotic centre 
and rim enhancement after IV contrast. 
– Squamous cell metastases are also typically necrotic. In contrast, 
lymphomatous nodes have a homogeneous appearance with minimal 
enhancement. 
– The rare condition, Castleman’s disease demonstratesmarked lymph node 
enhancement. 
Lymphoma. Multiple large-volume mesenteric lymph nodes (arrows), 
with additional confluent retroperitoneal nodal masses (asterisk). 
Necrotic ring-enhancing node secondary to a malignant gastric ulcer 
(not shown). Extensive soft tissue stranding present in the left upper 
quadrant from local tumour infiltration (asterisk). 
26/02/2016 
10 
Nodal tuberculosis. Multiple abdominopelvic ring-enhancing necrotic 
(caseous) nodes (arrows). 
Nodal tuberculosis. Multiple abdominopelvic ring-enhancing necrotic 
(caseous) nodes (arrows). 
Omental secondary deposits 
• The preferential sites for tumor implantation 
are the pelvic cul-de-sac, right paracolic gutter, 
and the greater omentum. 
• CT demonstrates tumor nodules on peritoneal 
surfaces; “omental cake”, which displaces 
bowel away from the anterior abdominal wall; 
tumor nodules in the mesentery; thickening 
and nodularity of the bowel wall due to 
serosal implants; and ascites that is commonly 
loculated. 
Peritoneal Metastases. A CT scan demonstrates intraperitoneal spread of ovarian 
carcinoma. The tumor is implanted on the omentum (arrows), causing the appearance of 
“omental cake” as the thickened omentum floats in ascites (A) between bowel loops and the 
abdominal wall. Nodules of tumor (arrowhead) are implanted on the peritoneal surface. 
Multiple peritoneal nodules (arrowheads) in a patient with ovarian 
carcinoma. 
Extensive omental cake (arrowheads) in a patient with ovarian 
carcinoma. 
26/02/2016 
11 
Retroperitoneal fibrosis 
• Retroperitoneal fibrosis (RPF) is the 
pathological formation of dense fibrotic tissue 
in the retroperiteum, that can lead to 
complications involving the vasculature, 
lymphatics and renal tracts. 
Radiological features 
• IVU(Intravenous urogram): 
– Classical triad of features: 
• bilateral ectasia of the ureters superior to L4/5 from 
impaired peristalsis. 
• ureters pulled medially by the fibrotic tissue. 
• gradual tapering of the ureters under extrinsic pressure 
from fibrotic tissue. 
– Generally mild hydronephrosis. 
 
• CECT: can show peri-aortic soft tissue, which 
may enhance if active inflammation is present. 
Retroperitoneal Fibrosis. Coronal plane-reconstructed CT performed without IV 
contrast shows poorly marginated soft tissue (arrows) encasing the distal aorta and common 
iliac vessels. The right ureter was enveloped and obstructed by the fibrosing process. A ureteral 
stent (arrowhead) is in place. The left kidney is absent. 
Retroperitoneal fibrosis. IVU 
demonstrates the classical 
features of 
medially ‘pulled’ ureters (arrow), 
ureteric tapering (arrowheads) 
and 
ureteric ectasia. 
Retroperitoneal fibrosis. CECT demonstrates circumferential soft 
tissue surrounding the aorta (arrowhead) and encasing the mid ureter 
(not shown); this results in moderate right hydronephrosis (arrow). 
Foreign bodies 
• AXR: 
– Detects radioopaque foreign bodies, such as metallic 
materials and some types of glass. 
– Can be useful for checking the position of medical 
devices, for example the ‘lost IUCD’, as well as 
screening postoperative patients when a surgical item 
is unaccounted for. 
– If an unexpected foreign body is found, always 
consider that it may be within the patient’s clothes. 
– Remember not all foreign bodies are radioopaque, for 
example wood. 
• CT: useful for assessing secondary complications 
of foreign bodies. 
26/02/2016 
12 
Foreign body. 
Swallowed screw 
within the 
stomach (arrow). 
Foreign body. 
Swallowed 
coin within 
the stomach 
(arrow). 
Foreign body. Retained forceps following a laparotomy. 
Foreign body. 
Mercury 
thermometer 
deliberately 
inserted into 
the 
bladder. 
Foreign body. 
Retained surgical swab 
(arrow). 
Foreign body. Large rectal foreign body. 
26/02/2016 
13 
Retained Surgical 
Sponge. A. Digital 
radiograph of the 
abdomen taken at 
bedside 
reveals the characteristic 
radiopaque tape (arrow) 
that marks a surgical 
sponge inadvertently left 
within the abdominal 
cavity. Metallic 
cutaneous staples 
identify the patient as 
having had recent 
surgery. 
B. CT reveals the difficulty of identifying the surgical sponge if the radiopaque marker (arrow) 
was not present. The sponge (between arrowheads) contains fluid, blood, and air bubbles 
producing a pattern very similar to stool in the colon. The descending colon (curved arrow) is 
displaced medially. 
Types of line/device 
• In the neonate, umbilical arterial and venous lines are commonly used. 
– The umbilical artery catheter is passed via the umbilical artery into the 
internal iliac artery and the infrarenal aorta. On AXR, it is seen to loop down 
into the pelvis before travelling in a cephalic direction to the left of the 
midline. The tip of the line should lie either above or below the renal arteries, 
between T8 and T12 or L3 and L4. 
– The umbilical vein catheter should traverse the umbilical vein, the portal sinus 
(junction of left and right portal vein), ductus venosus and IVC and end in the 
right atrium. On the abdominal film the catheter passes in a cephalic direction 
from its entry point and should lie above the liver in the right atrium. The 
umbilical vein catheter is easily misplaced in a portal or hepatic branch and 
the tip is then seen projected over the liver on AXR. 
• Femoral venous lines lie in the inguinal regions and pass in the iliac veins 
to the IVC. 
• Arterial stents within the abdominal aorta and iliac arteries have a mesh-
like appearance. 
• IVC filters look like the spokes of an umbrella and lie to the right of the 
midline on the abdominal film. 
Endovascular thoraco-
abdominal aortic stent seen in 
situ (arrows). 
Ureteric stent. Right double 
‘pigtail’ stent. 
Umbilical lines. The 
asterisks indicate 
cardiac monitoring 
leads. NGT, 
nasogastric tube; UVC, 
umbilical venous 
catheter; UAC, 
umbilical arterial 
catheter. 
26/02/2016 
14 
Percutaneous endoscopic 
gastrostomy. IVC filter 
(arrowhead) and tube 
(arrow) in situ. 
Urinary tract lines 
• The most commonly seen tube relating to the urinary tract 
on AXR is the urinary catheter, placed either via the urethra 
or the suprapubic route. 
• Ureteric stents have curled ends and lie lateral to the 
transverse processes of the vertebral bodies. Transplant 
kidneys may also have ureteric stents that lie in the pelvis. 
• Nephrostomy tubes placed percutaneously to drain an 
obstructed kidney are seen in the upper abdomen, with a 
coiled end in the renal angle and an external component. 
• Patients with renal failure on peritoneal dialysis have an 
intraabdominal catheter that is tunnelled under the skin 
before entering the abdomen and usually lies in the lower 
abdomen, although its position is variable. 
Cholecystectomy clips in 
the RUQ (arrowheads). 
Gynaecological lines/devices 
• Commonly identified devices include: 
– intrauterine contraceptive devices (‘the coil’) 
– sterilisation clips 
– ring pessary: used as conservative treatment for 
uterine prolapse. 
Intrauterine contraceptive 
device and sterilisation clips. 
The clip on 
the right side has migrated 
superiorly. 
Ring pessary in situ (arrow). 
26/02/2016 
15 
Gastrointestinal tract lines 
• Tubes commonly seen within the GI tract are 
nasogastric and nasojejunal tubes placed for feeding. 
To aid identification, the tips of the tubes are 
radioopaque and the tips of both should lie in the LUQ. 
The nasojejunal tube lies more distally within the 
bowel and follows the C-shaped loop of the 
duodenum, crossing the midline into the left side of 
the abdomen, to lie just distal to the duodenojejunal 
junction. 
• Stents placed within the biliarysystem, for example 
within the common bile duct, are visible on the 
abdominal film, lying in the RUQ. 
• Stoma devices. The position of these is naturally 
dependent on the procedure performed. 
Nasojejunal tube in situ. 
Stoma device 
seen in the 
LIF (arrows). 
Surgical drains 
• Drainage tubes are often present in 
postoperative patients; the site obviously 
relating to the procedure performed, and 
hence clinical history is important when 
looking at the AXR. 
Expandable biliary 
stent (arrowhead) 
and percutaneous 
pigtail drainage 
catheter (arrow) seen 
in situ within the 
RUQ. 
Abscesses within the abdomen 
• Development of an abscess is commonly insidious, and the clinical 
presentation is often nonspecific and confusing. 
• The pelvis is the most common site for abscess formation. 
• Radiographic findings include soft tissue mass, collection of 
extraluminal gas, displacement of bowel, localized or generalized 
ileus, elevation of the diaphragm, pleural effusion, and atelectasis 
or consolidation at the lung bases. A focal collection of extraluminal 
gas is the most specific sign of abscess but is uncommon. 
• CT shows a loculated fluid collection, often with internal debris and 
fluid–fluid levels. The walls of the fluid collection are often thick 
and irregular. Gas within the fluid collection is strong evidence of 
abscess. Fascia adjacent to the abscess is thickened, and fat 
surrounding the abscess may be increased in density and contain 
soft tissue strands because of inflammation. 
26/02/2016 
16 
Right subphrenic abscess and free air. Air–fluid level below the right 
hemidiaphragm (black arrowhead and white arrow) and a Riggler’s sign 
(white arrowhead). 
Large hepatic subcapsular abscess containing air (asterisk). Note the 
effacement of the adjacent right lobe of liver, confirming the 
subcapsular position. 
Post-appendicectomy abscess. Note the complex multiloculated 
collection deep to the incision (arrow). 
Liver abscess. Heterogeneous collection within the right lobe of the liver 
(arrow). 
Pelvic abscess. Complex collection (C) deep within the pelvis. B, bladder. Pelvic abscess (same patient). large fluid collection, containing pockets 
of air, deep within the pelvis (asterisk). 
26/02/2016 
17 
Abscess. CT reveals an abscess (arrows) in the retroperitoneum. The abscess 
contains fluid and gas (arrowhead). Note the discrete enhancing wall of the abscess. 
Duodenum (D) containing intraluminal gas is displaced anteriorly and is draped over the 
collection. 
CASOS 
Caso 01 
• 21 year-old with colicky pain and eosinophilia 
What is the most likely diagnosis? 
• Sprue 
• Intussusception 
• Ascariasis 
• Crohn Disease 
• Mechanical Large Bowel Obstruction 
 
Ascariasis 
• Imaging Findings 
– Chest may show fleeting, patchy areas of airspace 
disease 
– Long, tubular filling defects, especially in distal 
small bowel 
– The worm ingests barium and the barium may be 
seen as a thin line of contrast in the center of the 
worm, especially after the remainder of the 
barium exits the small bowel. 
– Ball of worms 
– Filling defects in the biliary system 
26/02/2016 
18 
Ascariasis. There are 
serpiginous filling defects in 
the distal small bowel (red 
arrows) 
representing adult 
roundworms. 
Caso 02 
 
What's the most likely diagnosis? 
• A. Generalized ileus 
• B. Small bowel obstruction 
• C. Large bowel obstruction 
• D. Free air 
 
Small Bowel Obstruction 
• Small Bowel Obstruction. Supine view of the 
abdomen (left) shows several dilated loops of 
small bowel 
in the upper abdomen. The small bowel is 
disproportionately dilated compared the the 
large bowel 
which is collapsed. The upright view (right) 
demonstrates multiple air-fluid levels in the 
dilated loops 
in a typical configuration of a small bowel 
obstruction. The patient had previous bowel 
surgery. 
CT of Small Bowel Obstruction. Axial CT scan through the lower abdomen shows 
multiple fluid-filled and dilated loops of small bowel (white arrows) and collapsed 
right colon (red arrow) consistent with a mechanical small bowel obstruction. 
26/02/2016 
19 
Caso 03 
• 63 year-old male with fever, tachycardia and 
leukocytosis 
What is the most likely diagnosis? 
• Small bowel obstruction 
• Perforation of the feeding tube 
• Toxic megacolon 
• Intussusception 
• Ankylosing spondylitis 
Toxic Megacolon (Toxic Colitis) 
• Potentially lethal dilation of all or part of the 
colon associated with acute toxic colitis. 
• Não há peristaltismo, o intestino grosso perde 
tônus e contratilidade. 
• Conventional radiography is usually diagnostic 
although CT scans are frequently obtained to 
rule out complications such as perforation 
• Dilation of the transverse colon 
– In the supine position, the transverse colon is 
normally the most anterior and therefore the 
most distended loop of large bowel 
– Abnormal dilatation of the transverse colon starts 
with at least 6 cm of transverse diameter but, 
when pathologic, is usually is larger than that 
• Thumbprinting from submucosal infiltration 
• Free air 
• Barium enema should not be performed 
Toxic Megacolon (Toxic 
Colitis). The transverse colon 
(TC) is markedly dilated and 
there is evidence of submucsal 
infiltration in the form of 
thumbprinting (white arrows). 
The patient had C. Difficle 
colitis. 
Caso 05 
• 58 year-old male with abdominal pain and 
constipation 
26/02/2016 
20 
What's the most likely diagnosis? 
• Pneumoperitoneum 
• Emphysematous cystitis 
• Diverticulitis 
• Gastric dilatation 
• Sigmoid volvulus 
Sigmoid Volvulus 
• Twisting of loop of intestine around its 
mesenteric attachment site may occur at 
various sites in the GI tract. 
• Redundant sigmoid colon that has a narrow 
mesenteric attachment to posterior 
abdominal wall allows close approximation of 
2 limbs of sigmoid colon à twisting of sigmoid 
colon around mesenteric axis. 
 
Diagnosis 
• Abdominal plain films usually diagnostic 
– Inverted U-shaped appearance of distended 
sigmoid loop 
• Largest and most dilated loops of bowel are seen with 
volvulus 
– Loss of haustra 
– Coffee-bean sign à midline crease corresponding 
to mesenteric root in a greatly distended sigmoid 
• Sigmoid volvulus – bowel loop points to RUQ 
• Cecal volvulus – bowel loop points to LUQ 
– Dilated cecum comes to rest in left upper quadrant 
– Bird’s-beak or bird-of-prey sign à seen on barium 
enema as it encounters the volvulated loop 
• CT scan useful in assessing mural wall 
ischemia 
 
Sigmoid 
Volvulus. Dilated loop 
of sigmoid colon has a 
"coffee-bean" shape 
and 
the wall between the 
two volvulated loops of 
sigmoid (black arrow) 
"points" towards the 
right upper quadrant. 
There is a considerable 
amount of stool in the 
colon from chronic 
constipation. 
Referências 
• BRAMBS, Hans-Juergen. Gastrointestinal 
Imaging (Direct Diagnosis in Radiology). 
Thieme, 2012. 
 
• BRANT, William E.; HELMS, Clyde A. 
(Ed.). Fundamentals of diagnostic radiology. 
Lippincott Williams & Wilkins, 2012. 
• HOLMES, Erskine J.; MISRA, Rakesh R. AZ of 
emergency radiology. Cambridge University 
Press, 2004. 
• JUHL, John H.; CRUMMY, Andew B.; 
KUHLMAN, Janet E. Interpretação 
radiológica. Interpretação radiológica, 2000. 
• WEBB, Wayne Richard; BRANT, William E.; 
MAJOR, Nancy M. Fundamentals of body CT. 
Elsevier Health Sciences, 2006. 
 
 
• GAILLARD, F. Appendicolith; Radiopaedia. org. 
2014. 
• William Herring. LEARNING RADIOLOGY, 2014