IMAGING PATIENTS WITHIMAGING PATIENTS WITH

ACUTE ABDOMINAL PAIN ACUTE ABDOMINAL PAIN

OverviewOverviewImaging modalitiesIndications Systematic approach to

abdominal x-rayClinical scenario

Imaging ModalitiesImaging Modalities

1. Plain Abdominal Radiograph2. Ultrasound FAST Formal US3.CT

AXR - IndicationsAXR - IndicationsSuspected bowel obstruction Suspected perforationSuspected foreign bodyModerate to severe

undifferentiated abdominal painRenal tract calculi follow-up(Exclude pregnancy)0.1-1 mSv

Abdominal Ultrasound - Abdominal Ultrasound - IndicationsIndicationsTrauma survey and follow up

(FAST)Suspected acute cholocystitisSuspected acute pyelonephritis –

single kidney, transplant, immunocompromised, abnormal renal function, DM, cong anomalies, recurrent/failed to respond to AB, equivocal

RIF pain – young femalesAscites localization

Abdominal CT - IndicationsAbdominal CT - IndicationsAppendicitisColitis (Inflammatory, infective,

ischaemic), DiverticulitisPerforation – Normal erect CXR

strong clinical suspicionStrong suspicion of bowel

obstruction on AXR – further investigation (If not for urgent surgery), uncertainty about the site of obstruction

Urolithiasis AAA/rupture

CT vs USCT vs USRadiation dose (10mSv for

abdominal CT)Patient’s age <25yrs Estimated risk of induced cancer 1

in 900 Estimated risk of induced fatal

cancer 1 in 1800

Body habitus

CTCTHigh sensitivityHigh specificityAvailabilityNot real time, but dynamic study

(artery,vein, delayed phases)Lack of operator dependence

USUSInexpensivePortableSafeDynamic and real time survey

Operator dependence

AXRAXROften anatomical structures are not

demonstratedAbnormalities can be obscured by

anatomical structuresStomach – seen when it contains

air, LUQSmall bowel – generally central,

valvulae conniventesLarge bowel – peripheral, haustra,

retroperitoneal colon is relatively constant in position

AXR AXR Soft tissue – assessment is

limited liver, spleen, psoas, kidney,

bladder, lung basesBones – landmarks ureters, VUJAdded densities – artifacts or

calcified soft tissue

AXRAXR

Abdominal painAbdominal painPlain AXR 1.Strong suspicion of small bowel

obstruction2.Strong suspicion of large bowel

obstruction3.Uncertainty about the site of

obstruction69% sensitivity and 57% specificity

for bowel obstruction

Strong suspicion of paralytic ileus or psedo-obstruction – no imaging

Strong suspicion of small Strong suspicion of small bowel obstruction - AXRbowel obstruction - AXRNo further imaging - needs urgent surgery - known adhesive obstruction and

to be managed conservativelyFurther Imaging - acute high grade symptoms

CT- 94% sensitivity 96% specificitySensitivity low (64%) for low grade

SBO

Suspected large bowel Suspected large bowel obstructionobstructionSigns of volvulus – contrast enema CTSuspected complicated diverticulitis –

CT Likely obstructing lesion – CT (mural

changes and transcolonic abnormalities) Contrast

enema

Colon 5.5 cm, cecum 10cmCT 96% sensitivity, 93% specificity

Sentinel loop in pancSentinel loop in panc

Paralytic ileusParalytic ileus

Coffee bean in sigmoid volvCoffee bean in sigmoid volv

Caecal volvCaecal volv

PerforationPerforationPeptic ulcerDiverticulitisMalignancy

CXR – insensitive for air pockets <1mm

less sensitive for 1-13mmCT – 86% can detect the site of

perforation

Bowel ischemiaBowel ischemiaAccuracy of CT is comparable to

angiographySensitivity 93% and 96%

respectivelySpecificity 79% and 99%

respectively

Arterial and PV phases – ischemia could be arterial or venous

Bowel ischaemiaBowel ischaemia

Cases

Suspected acute Suspected acute cholecystitischolecystitisUS (88% sensitivity 80%

specificity)Acute abdominal pain - CT has

demonstrated accuracy comparable to that of US in diagnosing acute cholecystitis

Cholestatic jaundiceCholestatic jaundiceUS – to assess duct dilatation Yes – cause identified – treat cause not identified suspect stone -

MRCP/CTIVC/EUS suspect malignancy

– CT No – consider hepatocellular

Acute LIF painAcute LIF painFemale of reproductive age – US

to exclude gynaecological pathology

Suspected acute diverticulitis – CT

Suspected renal colic 1st/recurrent presentation, age

(>/<50y), pregnantOther - CT

Acute RIF painAcute RIF painHigh likelihood of appendicitis –

young patient (US to exclude gynae pathology)

Atypical for appendicitis young or thin patients – US others – CT

Graded compression – to identify non compressible bowel

DiverticulitisDiverticulitis

Ovarian torsionOvarian torsion

Acute PancreatitisAcute PancreatitisClinical and biochemicalUS – gall stonesCT- diagnosis uncertain assessment of severe cases failure to improve or sudden

clinical deterioration clinically suggestive of

developing complications follow up

Scrotal painScrotal pain

USTraumaEpididymo-orchitis?? Torsion

EpidydimitisEpidydimitis

TorsionTorsion

TraumaTrauma

1. FAST – Focussed Assessment with Sonography for Trauma

2. CT

Small bowel obstructionSmall bowel obstruction

Small bowel obstructionSmall bowel obstruction

PneumoperitoneumPneumoperitoneum

PneumoperitoneumPneumoperitoneum

ColitisColitis

AppendicitisAppendicitis

THANK YOUTHANK YOU