Table Of ContentIMAGING OF THE ACUTE ABDOMEN
CONTENTS
Preface xi
Emil J. Balthazar
Impact of Multislice CT on Imaging of Acute Abdominal Disease 1083
Vikas Kundra and Paul M. Silverman
With the advent of multislice CT, higher resolution and more diagnostic images are
now available. By transitioning from axial to single-slice helical to now multislice CT
scanners, imaging time has been reduced from minutes to seconds. In addition, colli-
mation width and computing time have decreased. Increased coverage is now
obtained with thinner slices and higher image quality. Although multislice CT has
had significant impact in evaluating the entire body, it has been particularly useful for
abdominal imaging.
Radiologic Diagnosis of Gastrointestinal Perforation 1095
Stephen E. Rubesin and Marc S. Levine
Perforations of the gastrointestinal tract have many causes. Holes in the wall of gas-
trointestinal organs can be created by blunt or penetrating trauma, iatrogenic injury,
inflammatory conditions that penetrate the serosa or adventitia, extrinsic neoplasms
that invade the gastrointestinal tract, or primary neoplasms that penetrate outside the
wall of gastrointestinal organs. This article provides a radiologic approach for inves-
tigating the wide variety of gastrointestinal perforations. General principles about
contrast agents and studies are reviewed, and then perforations in specific gastroin-
testinal organs are discussed.
The Acute Right Lower Quadrant: CT Evaluation 1117
Michael Macari and Emil J. Balthazar
This article describes the CT imaging findings of patients presenting with acute right
lower quadrant pain. The focus is on appendicitis and current imaging techniques and
controversies. The remainder of the article evaluates the most common conditions caus-
ing right lower quadrant pain other than appendicitis that can be diagnosed with CT.
Adult Intussusception: Diagnosis and Clinical Relevance 1137
Benjamin Y. Huang and David M. Warshauer
Adult intussusception is a rare entity. Unlike intussusceptions in childhood, most adult
intussusceptions are caused by a definable pathologic lesion, with a significant proportion
VOLUME 41 •NUMBER 6 •NOVEMBER 2003 v
caused by malignancy, particularly among those involving the colon. Before the advent
of noninvasive imaging, most adult intussusceptions were diagnosed surgically or at
autopsy, but modern imaging techniques have proved useful in diagnosis and in direct-
ing appropriate therapy. Until recently, adult intussusception had been considered pri-
marily a surgical condition, but recent data in the radiologic literature suggest that there
may be a substantial number of transient, nonneoplastic enteroenteric intussusceptions
diagnosed by CT, which do not require operative treatment.
CT of Acute Abdominal Aortic Disorders 1153
Sanjeev Bhalla, Christine O. Menias, and Jay P. Heiken
Aortic aneurysm rupture, aortic dissection, penetrating atherosclerotic ulcer, acute
aortic occlusion, traumatic aortic injury, and aortic fistula represent acute abdominal
aortic conditions. Because of its speed and proximity to the emergency department,
helical CT is the imaging test of choice for these conditions. MR imaging also plays an
important role in the imaging of aortic dissection and penetrating atherosclerotic
ulcer. Ultrasound is helpful when CT is not readily available and the patient is unable
or too unstable to undergo MR imaging. Because CT is the dominant imaging method
for diagnosing acute abdominal aortic conditions, this article focuses on CT tech-
niques and manifestations of this group of acute abdominal disorders.
Blunt Injury to Mesentery and Small Bowel: CT Evaluation 1171
Patrick W. Hanks and Jeffrey M. Brody
CT is widely used in the evaluation of trauma patients. Although the sensitivity for CT
detection of solid organ injury is 90% or better, hollow viscous injury has historically
been more difficult to identify. Diagnosis of small bowel and mesenteric injury often
requires special attention to subtle findings. This article discusses the role of CT in the
diagnostic approach to blunt trauma victims, the points of controversy regarding the CT
examination technique, the CT findings related to small bowel and mesenteric injury,
and the accuracy of imaging diagnosis.
Spontaneous Intraperitoneal Hemorrhage: Imaging Features 1183
Koenraad J. Mortele, Vito Cantisani, Douglas L. Brown, and Pablo R. Ros
Spontaneous, nontraumatic, intraperitoneal bleeding is a rare but worrisome clinical
condition, potentially fatal, which may be related to a vast array of underlying causes.
Accurate diagnosis of the cause, organ of origin, extent, and prognosis of this condition
can be established with different imaging modalities, such as ultrasound, CT, and MR
imaging. This article summarizes the clinical aspects and pathogenesis of the entities
causing spontaneous intraperitoneal hemorrhage. The corresponding radiologic features
of these conditions are highlighted. Finally, recommendations to perform the imaging
modality of choice for each of the abnormalities and key features are provided.
Ultrasound and CT Evaluation of Emergent Gallbladder Pathology 1203
Genevieve L. Bennett and Emil J. Balthazar
This article provides a review of ultrasound and CT findings in acute conditions of the
gallbladder. Although ultrasound or hepatobiliary scintigraphy are usually the initial
imaging examinations of choice to evaluate most suspected cases of acute gallbladder
pathology, the role of CT in the evaluation of abdominal pain continues to expand.
CT allows for more comprehensive evaluation of the abdomen and pelvis and can iden-
tify other inflammatory processes that clinically may simulate gallbladder pathology.
vi CONTENTS
In many instances, CT may be the initial diagnostic procedure performed; it is important
to become familiar with the spectrum of CT findings in emergent gallbladder disorders.
Furthermore, CT plays an important role in the evaluation of associated complications of
these disorders, facilitating prompt diagnosis and appropriate management.
Interventional Approach to Pancreatic Fluid Collections 1217
Joseph T. Ferrucci III and Peter R. Mueller
Interventional radiologic catheter drainage may be an effective therapeutic approach to
fluid collections complicating acute pancreatitis. Pancreatic pseudocysts and abscess are
the most common conditions requiring radiologic intervention. Imaging guidance is best
performed under CT control allowing precise definition of access route, catheter place-
ment, and response. Access routes are chosen to avoid traversing vital intervening struc-
tures, especially the pleural space, colon, and small bowel. Optimal results are achieved
with the use of large-bore multihole catheters, prolonged duration of drainage, and care-
ful collaboration with the surgical team.
Ultrasonography of the Acute Abdomen: Gastrointestinal Conditions 1227
Julien B.C.M. Puylaert
Although multislice, helical CT is increasingly replacing ultrasonography for the evalua-
tion of patients with acute abdominal pain, ultrasound does have certain specific
advantages over CT. This article discusses the advantages of ultrasound in imaging of
the acute abdomen, exploring such areas as appendicitis, ileocecal Crohn’s disease, infec-
tious ileocolitis and infectious ileocecitis, mesenteric lymphadenitis, cecal carcinoma, sig-
moid diverticulitis, right-sided colonic diverticulitis, and perforated peptic ulcer.
MR Imaging in Abdominal Emergencies 1243
Ivan Pedrosa and Neil M. Rofsky
The use of MR imaging in the emergency setting is evolving. Clear indications include situa-
tions in need of contrast media when iodinated contrast cannot be administered or to facili-
tate assessments in pregnant patients and children when exposure to ionizing radiation is
considered unacceptable. The availability of rapid, motion immune sequences now makes
MR imaging a feasible study in less cooperative patients extending the range of patients for
whom a diagnostic study can be achieved. Further investigations are needed to identify the
diagnostic algorithms for which this favorable use holds true.
Selective Role of Nuclear Medicine in Evaluating the Acute Abdomen 1275
Lionel S. Zuckier and Leonard M. Freeman
Evaluation of the acute abdomen has evolved with the introduction of the high-resolution
imaging techniques of CT, ultrasound, and MR imaging, leaving scintigraphic examina-
tions a limited although important role based on their noninvasive, physiologic, and
functional nature. Bleeding studies can be used to localize noninvasively sites of bleed-
ing to regions of the large or small bowel. Pertechnetate studies accurately localize sites
of ectopic gastric mucosa. Biliary scintigraphy is helpful in diagnosing patients with
acute presentation of biliary disease and is invaluable in analyzing complicated post-
cholecystectomy patients. Vascular and traumatic injury of the solid organs can be studied
by various functional techniques including biliary and renal scintigraphy. Aniche for
infectious imaging has been found in the evaluation of acute appendicitis.
CONTENTS vii
Complications of Liver Transplantation: Imaging and Intervention 1289
Michael P. Federle and Vibhu Kapoor
Orthotopic liver transplantation is the accepted treatment for end-stage liver disease.
Improvements in surgical techniques and medical therapy have resulted in reduced mor-
tality and some types of complications. Patients are, however, still at risk for a variety of
vascular, biliary, neoplastic, and other complications, the signs and symptoms of which
are often nonspecific. Radiologists can play a key role in diagnosis and management of
these complications, as reviewed in this article.
Cumulative Index 2003 1307
viii CONTENTS
FORTHCOMING ISSUES
January 2004
Arthritis Imaging
Barbara N. Weissman, MD, Guest Editor
March 2004
Emergency Ultrasound
Vikram Dogra, MD, Guest Editor
May 2004
Cardiac Imaging
Martin Lipton, MD, and
Lawrence Boxt, MD, Guest Editors
RECENT ISSUES
September 2003
Advances in Renal Imaging
Philip J. Kenney, MD, Guest Editor
July 2003
Women’s Imaging: Obstetrics and Gynecology
Deborah Levine, MD, Guest Editor
May 2003
Multislice Helical CT of the Thorax
Phillip M. Boiselle, MD, Guest Editor
THE CLINICS ARE NOW AVAILABLE ONLINE!
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RadiolClinNAm41(2003)xi–xii
Preface
Imaging of the acute abdomen
EmilJ.Balthazar,MD
GuestEditor
The only constantin life ischange. imagingmodalityoraprotocolshouldbebasedmainly
ontheirreportedaccuracy,sensitivity,andspecificity,
—Buddha asmightbeexpected.Inreality,however,theselection
processisstronglyinfluencedbypastexperienceand
Ithasbeenover10yearssincethepublicationof skills, the quality and availability of equipment, and
the last issue of the Radiologic Clinics of North thecostofexamination,andisthereforeofteninstitu-
Americadevotedentirelytoimagingacuteabdominal tionallydependent.Intheseventeenthcentury,Francis
disorders. Significant advances in technology, new Bacon and the French philosopher Rene´ De´scartes
applications,changedprotocols,andconsiderableac- identified observation and analysis, respectively,
cumulatedexperiencehavepromptedanupdateofthis astheprimarytoolsthatareessentialintheeffortto
importantclinicalsubject. acquirereliablescientificknowledge.Theprocessof
The purpose of this new issue is twofold. First, gathering data andanalysis, however, canbebiased,
acuteabdominalconditionsthatcanbediagnosedand tinted by our own prejudices, and is not always
evaluated rapidly by relatively noninvasive imaging trustworthy.InthewordsofhistorianJacqueBarzun:
examinationsarereviewed.Ihavetriedtoavoidover- ‘‘Observationisrarelyneutral;itrestsonpreconcep-
lapsandduplicationswhilemaintainingtherelevance tionsandpreperceptions.’’
ofthetopicbyfocusingonpertinent,potentiallylife- I hope that this issue describes what is presently
threatening abdominal conditions. Second, this issue availableandwhatisconsideredcurrentstate-of-the-
providesanabbreviatedbutcomprehensivepresenta- art in the imaging of acute abdominal conditions. A
tionofnewapplicationsofimagingmodalities—such compendium of imaging choices and protocols are
asmultidetector(multislice)CT,sonography,andMR described, mainly reflecting the experience and con-
imaging—thatwerepreviouslynotavailableorwere victionsofdifferentauthors.Ifoundtheserecommen-
notcommonlyusedintheevaluationofpatientswith dations very useful; however, they arenot axioms—
acuteabdominalcomplaints. and are certainly not perennial—but are susceptible
After perusing through this issue, readers will no to incessant changes and refinements. It is your re-
doubt notice that radiologists, based on their experi- sponsibilityasthereader,basedonyourskills,expe-
ence and established beliefs, tend to address similar rience, and local factors, to select the appropriate
clinical challenges by different means using various imaging modality and the required protocol that, in
imagingmodalitiesordistinctlyidiosyncratictechni- your best judgment, will better serve the interest of
cal protocols. Theoretically, the selection of a given yourpatients.
0033-8389/03/$ – seefrontmatterD2003ElsevierInc.Allrightsreserved.
doi:10.1016/S0033-8389(03)00142-8
xii E.J.Balthazar/RadiolClinNAm41(2003)xi–xii
In pursuing my goals, I have been joined and EmilJ. Balthazar,MD
helpedbyadistinguishedgroupofleadingacademic Department of Radiology
radiologists,allexpertsintheirfield,towhomIextend New York University Schoolof Medicine
my affection and gratitude. I am also indebted to 560First Avenue,NB3 W39
BartonDudlick,ourefficientsenioreditor,forhelping New York,NY 10016,USA
usmakethisprojectareality. E-mailaddress: [email protected]
RadiolClinNAm41(2003)1083–1093
Impact of multislice CT on imaging of
acute abdominal disease
Vikas Kundra, MD, PhD*, Paul M. Silverman, MD
DivisionofDiagnosticImaging,DepartmentofRadiology,TheUniversityofTexas,M.D.AndersonCancerCenter,
Box57,Houston,TX77030,USA
WiththeadventofmultisliceCT(MSCT),higher the need for cooling; thus, x-rays can be delivered
resolution and more diagnostic images are now continuously. With MSCT, the point source is pro-
available. By transitioning from axial to single-slice jectedontomultipledetectors,currentlyupto16,inthe
helical to now MSCT scanners, imaging time has Zaxisinsteadofthesingledetectorofpriorsystems.
been reduced from minutes to seconds. In addition, Therefore,moredataareacquiredwithasinglegan-
collimation width and computing time have de- tryrotation.
creased. Increased coverage is now obtained with Forimageacquisition,generallythreemajordetec-
thinner slices and higher image quality. Although tors designsareused: (1) matrix, whereall detectors
MSCT has had significant impact in evaluating the are of the same size; (2) adaptive array, where they
entire body, it has been particularly useful for ab- vary from thinner inside to thicker outside; and
dominalimaging. (3)hybrid,whereusuallytwosizesareusedwiththe
Forexample,differentphasesofenhancementcan thinner detectors located centrally [2]. The first two
now be separated more succinctly. Reduced breath- support submillimeter to 5-mm acquisitions modes,
holdtimeshaveresultedinmorediagnosticscansby whereas the latter supports submillimeter to 8-mm
curtailing motion artifact. Thinner slices have de- acquisitionmodes
creasedZ-axisblurringtoallowevaluationofminute Multislicescannersaltertheacquisitionthickness
structures, such as blood vessels. Increased comput- byvaryingthenumberofdetectorsused(Fig.2).For
ing speed has also shortened reconstruction and example,afour-slicescannerusingthematrixdesign
reformation times, enabling selection of the optimal hasaZ-axiswidthof20mmsubdividedinto16equal
planeforthestructureinquestion.Clinically,imaging parts of 1.25 mm each. The beam is collimated to
findingsonCTincreasethecertaintyofdiagnosisor exciteacertainnumberofrows.Slicesareacquiredin
offer an alternative diagnosis to guide patient man- groupsoffour.Ifthecentralfourrowsareused,four
agement [1]. slices of 1.25-mm thickness are obtained for total
coverageof5mm.Ifthecentraleightareused,every
twodetectorsaresummedresultinginaslicethickness
Technology of 2.5 mm. If the central 12 are used, every three
detectorsaresummedresultinginaslicethicknessof
Insimpleterms,MSCTallowsacquisitionofmul- 3.75 mm. If all detectors are used, every four are
tiplesliceswithasinglegantryrotation(Fig.1).New summedresultingin5-mmslicescovering20mmin
high heat capacity tubes have significantly reduced theZaxis.Forsubmillimeterresolution,thebeamis
collimatedacrossdetectors.
Withthenew16-slicescanners,16slicesmaybe
* Correspondingauthor. obtainedwithasinglegantryrotation,includingatsub-
E-mailaddress:[email protected] millimeterresolution.Thisdoesnotincreasethespeed
(V.Kundra). ofacquisitionfor5-mmslicescomparedwithafour-
0033-8389/03/$ – seefrontmatterD2003ElsevierInc.Allrightsreserved.
doi:10.1016/S0033-8389(03)00117-9
1084 V.Kundra,P.M.Silverman/RadiolClinNAm41(2003)1083–1093
Fig.1.Single-sliceversusMSCT.InsteadofasingledetectorintheZaxisusedinsingle-sliceCT,MSCThasmultipledetectors
intheZaxis,providingagreaternumberofimagespergantryrotation.
slicescanner(4(cid:1)5mm=20mm)becausethemaxi- In addition to varying collimation at the time of
mum width for detection in the Z axis is 20 mm. It acquisition, slice thickness may also be varied by
does,however,increasecoveragewhenthinnerslices manipulating how the data are reconstructed. Al-
areused.Forexample,at1.25-mmcollimation,afour- though slices can be reconstructed at thicker widths
slice scanner covers 5 mm per gantry rotation (4 (cid:1) than those acquired, they cannot be reconstructed
1.25mm=5mm),whereasa16-slicescannercovers thinner. Thus, it is important to select the thinnest
20mmpergantryrotation(16(cid:1)1.25mm=20mm). acquisition widthneeded atthe time ofscanning.
Fig.2.Matrixdetector.(A)Inthematrixconfiguration,theZaxisisdividedintoequalparts.Forafour-slicescanner,20mmin
theZaxisiscoveredby16detectorseachmeasuring1.25mm.TheX-raybeamiscollimatedtoexposethecentral4,8,12,or
16 detectors. At the time of acquisition, data from the detectors may be added, resulting in slices of varying thickness. For
example,byexposingthecentraleightdetectorsandcombiningdatafromeverytwo,four2.5-mmslicesareobtained.(B)Witha
16-slicescanner,16differentacquisitionsmaybeobtainedatsubmillimeterresolutionwithasinglegantryrotation.Intermsof
areaintheZaxis,1.25-mmslicescover20mminsteadof5mmbyfour-slicescanners.Becausethetotaldetectorwidthisthe
same,thereisnodifferenceinZ-axiscoverageif5-mmslicesareacquired.
