Pearls and Pitfalls in EMERGENCY RADIOLOGY Variants and Other ffi Di cult Diagnoses Downloaded from Cambridge Books Online by IP 128.122.149.154 on Mon Mar 18 17:35:20 WET 2013. http://ebooks.cambridge.org/ebook.jsf?bid=CBO9781139135047 Cambridge Books Online © Cambridge University Press, 2013 Downloaded from Cambridge Books Online by IP 128.122.149.154 on Mon Mar 18 17:35:20 WET 2013. http://ebooks.cambridge.org/ebook.jsf?bid=CBO9781139135047 Cambridge Books Online © Cambridge University Press, 2013 Pearls and Pitfalls in EMERGENCY RADIOLOGY Variants and ffi Other Di cult Diagnoses Edited by Martin L. Gunn AssociateProfessor DepartmentofRadiology UniversityofWashington Seattle,WA,USA Downloaded from Cambridge Books Online by IP 128.122.149.154 on Mon Mar 18 17:35:20 WET 2013. http://ebooks.cambridge.org/ebook.jsf?bid=CBO9781139135047 Cambridge Books Online © Cambridge University Press, 2013 cambridge university press Cambridge,NewYork,Melbourne,Madrid,CapeTown, Singapore,SãoPaulo,Delhi,MexicoCity CambridgeUniversityPress TheEdinburghBuilding,CambridgeCB28RU,UK PublishedintheUnitedStatesofAmericabyCambridgeUniversityPress,NewYork www.cambridge.org Informationonthistitle:www.cambridge.org/9781107021914 #MartinL.Gunn2013 Thispublicationisincopyright.Subjecttostatutoryexception andtotheprovisionsofrelevantcollectivelicensingagreements, noreproductionofanypartmaytakeplacewithout thewrittenpermissionofCambridgeUniversityPress. Firstpublished2013 PrintedandboundintheUnitedKingdombytheMPGBooksGroup AcatalogrecordforthispublicationisavailablefromtheBritishLibrary LibraryofCongressCataloginginPublicationdata Gunn,MartinL. Pearlsandpitfallsinemergencyradiology:variantsandotherdifficultdiagnoses/ MartinL.Gunn. p.;cm. Includesbibliographicalreferencesandindex. ISBN978-1-107-02191-4(Hardback) I. Title. [DNLM:1. Radiography–methods–CaseReports. 2. Diagnosis,Differential–Case Reports. 3. Emergencies–CaseReports.WN445] 616.070572–dc23 2012025997 ISBN978-1-107-02191-4Hardback CambridgeUniversityPresshasnoresponsibilityforthepersistenceor accuracyofURLsforexternalorthird-partyinternetwebsitesreferredto inthispublication,anddoesnotguaranteethatanycontentonsuch websitesis,orwillremain,accurateorappropriate. Everyefforthasbeenmadeinpreparingthisbooktoprovideaccurateand up-to-dateinformationwhichisinaccordwithacceptedstandardsand practiceatthetimeofpublication.Althoughcasehistoriesaredrawnfrom actualcases,everyefforthasbeenmadetodisguisetheidentitiesofthe individualsinvolved.Nevertheless,theauthors,editors,andpublisherscan makenowarrantiesthattheinformationcontainedhereinistotallyfree fromerror,notleastbecauseclinicalstandardsareconstantlychanging throughresearchandregulation.Theauthors,editors,andpublishers thereforedisclaimallliabilityfordirectorconsequentialdamagesresulting fromtheuseofmaterialcontainedinthisbook.Readersarestrongly advisedtopaycarefulattentiontoinformationprovidedbythemanufacturer ofanydrugsorequipmentthattheyplantouse. Downloaded from Cambridge Books Online by IP 128.122.149.154 on Mon Mar 18 17:35:20 WET 2013. http://ebooks.cambridge.org/ebook.jsf?bid=CBO9781139135047 Cambridge Books Online © Cambridge University Press, 2013 Contents List of contributors viii Preface ix Acknowledgments x Section 1 Brain, head, and neck Case 24 Motion artifact simulatingspinal fracture Ken F. Linnau 84 Case 25 Pars interarticularis defects Michael J. Modica 87 Neuroradiology: extra-axial and vascular Case 26 Limbus vertebra Joel A.Gross 90 Case1 IsodensesubduralhemorrhageMichaelJ.Modica 1 Case 27 Transitional vertebrae Joel A. Gross 92 Case 2 Non-aneurysmal perimesencephalic subarachnoid Case 28 Subtle injuriesin ankylotic spine disorders hemorrhage Robert B. Carr 5 Matthew H.Nett 95 Case 3 Missedintracranial hemorrhage RobertB. Carr 8 Case 29 Spinal dural arteriovenousfistula Case 4 Pseudo-subarachnoid hemorrhage Michael J. Modica 98 Robert B.Carr 11 Case 5 Arachnoid granulations Robert B. Carr 14 Section 3 Thorax Case 6 Ventricular enlargement Robert B. Carr 17 Case 7 Bluntcerebrovascularinjury Robert B. Carr 21 Case 30 Pseudopneumomediastinum Randy K. Lau 101 Case 8 Internal carotidartery dissection presenting as Case 31 Traumaticpneumomediastinum without subacute ischemic stroke MichaelJ. Modica 24 aerodigestiveinjury RandyK. Lau 105 Case 9 Mimics of dural venous sinus thrombosis Case 32 Pseudopneumothorax Randy K. Lau 108 Michael J. Modica 27 Case 33 Subcutaneous emphysemaand mimickers Case 10 Pineal cyst RobertB. Carr 32 Randy K.Lau 113 Case 34 Tracheal injury Randy K.Lau 116 Neuroradiology: intra-axial Case 35 Pulmonary contusion and laceration Randy K.Lau 118 Case 11 Enlarged perivascular space Michael J. Modica 36 Case 36 Sternoclavicular dislocation Randy K.Lau 121 Case 12 Tumefactive multiple sclerosis Case 37 Boerhaavesyndrome Randy K.Lau 125 Michael J. Modica 43 Case 38 Variants and hernias of the diaphragm simulating Case 13 Cavernousmalformation simulating contusion injury Randy K. Lau 128 Michael J. Modica 47 Case 14 Diffuse axonal injury Robert B. Carr 53 Section 4 Cardiovascular Neuroradiology: head and neck Case 39 Aortic pulsation artifact Randy K. Lau 131 Case 15 Orbital infection Robert B.Carr 56 Case40 Mediastinalwideningduetonon-hemorrhagiccauses Case 16 Globeinjuries Robert B. Carr 60 Randy K.Lau 133 Case17 DilatedsuperiorophthalmicveinRobertB.Carr 63 Case 41 Aortic injury with normalmediastinal width Case 18 Orbital fractures RobertB. Carr 66 Martin L. Gunn 138 Case 42 Retrocrural periaortic hematoma Section 2 Spine Martin L. Gunn 141 Case 43 Mimicks of hemopericardium on FAST Case 19 Variants of the upper cervical spine Matthew H.Nett 144 Robert B. Carr 69 Case 44 Mimicks of acute thoracicaortic syndromes:aortic Case 20 Atlantoaxial rotatoryfixation versus head rotation dissection,intramural hematoma, and penetrating Claire K. Sandstrom 72 aortic ulcer Martin L. Gunn 146 Case 21 Cervical flexion andextension radiographs after Case 45 Aortic intramural hematomaMatthew H.Nett 151 blunt trauma Ken F. Linnau 75 Case 46 Pitfalls in peripheral CTangiography Case 22 Pseudosubluxation of C2–C3 Robert B. Carr 79 Martin L. Gunn 153 Case 23 Calcific tendinitisof the longus colli Case 47 Breathing artifactsimulating pulmonaryembolism Matthew H.Nett 82 Martin L. Gunn 155 v Downloaded from Cambridge Books Online by IP 128.122.149.154 on Mon Mar 18 17:35:49 WET 2013. http://ebooks.cambridge.org/ebook.jsf?bid=CBO9781139135047 Cambridge Books Online © Cambridge University Press, 2013 Contents Case 48 Acute versus chronicpulmonarythromboembolism Case 70 Avoiding missed injuries to the bowel and Randy K.Lau 159 mesentery: theimportance of intraperitoneal fluid Case 49 Vascular embolization of foreign body Martin L. Gunn 232 Martin L. Gunn 162 Obstetrics and gynecology Section 5 Abdomen Case 71 Endometrialhypodensity simulating fluid Martin L. Gunn 237 Case 50 Simulated active bleedingJoel A. Gross 165 Case 72 PseudogestationalsacJoel A.Gross 244 Case 51 PseudopneumoperitoneumMartin L. Gunn 167 Case 73 Cystic pelvicmass simulating the bladder Case 52 Intra-abdominal focal fat infarction:epiploic Joel A.Gross 246 appendagitis and omental infarction Case 74 Ovarian torsion JoelA. Gross 248 Claire K. Sandstrom 170 Case 75 Urine jetssimulating abladder mass Case 53 False-negative andFalse-positiveFAST Ken F. Linnau 250 Martin L. Gunn 175 Case 76 Extraluminalbladder Foley catheter Joel A.Gross 252 Liver and biliary Case 77 Missed bladder rupture Joel A. Gross 255 Case 54 Diaphragmatic slip simulatingliver laceration Michael J. Modica 179 Section 7 Musculoskeletal Case55 Gallbladderwallthickeningduetonon-biliarycauses Claire K. Sandstrom 182 Case 78 Pseudofracture from motion artifact Claire K. Sandstrom 258 Spleen Case 79 Mach effectClaire K.Sandstrom 267 Case 56 Splenic clefts MichaelJ. Modica 187 Case 80 Foreign bodies not visible on radiographs Case 57 Inhomogeneous splenic enhancement Ken F. Linnau 272 Michael J. Modica 189 Case 81 Accessory ossicles Claire K. Sandstrom 274 Case 58 Pseudosubcapsular splenic hematoma Case 82 Fatpad interpretationClaire K. Sandstrom 285 Michael J. Modica 192 Case 83 Posteriorshoulder dislocation Claire K. Sandstrom 291 Pancreas Case 84 Easily missedfractures inthoracic trauma Claire K. Sandstrom 298 Case 59 Pseudopancreatitis followingtrauma Case 85 Sesamoidsand bipartitepatella Martin L. Gunn 194 Claire K. Sandstrom 303 Case 60 Pancreatic clefts Michael J. Modica 196 Case 86 Subtle knee fracturesClaire K. Sandstrom 309 Case 87 Lateral condylar notch sign Bowel Claire K. Sandstrom 313 Case 61 Pseudothickening of the bowelwall Case 88 Easily missedfractures of thefoot and ankle Martin L. Gunn 199 Ken F. Linnau 316 Case 62 Small boweltransientintussusception Joel A.Gross 203 Section 8 Pediatrics Case 63 Duodenal diverticulum Martin L. Gunn 205 Case 64 Pseudopneumatosis Martin L.Gunn 210 Case 89 Thymus simulatingmediastinal hematoma Case 65 Pneumatosisintestinalis Ken F. Linnau 213 Ken F. Linnau 320 Case 66 Pseudoappendicitis Martin L. Gunn 217 Case 90 Foreign body aspiration RameshS. Iyer 322 Case 91 Idiopathic ileocolic intussusception Kidney and ureter Ramesh S. Iyer 325 Case 67 Missed renal collecting system injury Case 92 Ligamentouslaxityand intestinalmalrotation in the Joel A.Gross 222 infant Ramesh S. Iyer 331 Case 68 Pseudohydronephrosis Ken F.Linnau 225 Case 93 Hypertrophicpyloric stenosis and pylorospasm Ramesh S. Iyer 335 Case 94 Retropharyngeal pseudothickening Section 6 Pelvis Ramesh S. Iyer 338 Case 69 Physiologic pelvic intraperitoneal fluid Case 95 Cranial sutures simulatingfractures Martin L. Gunn 230 Ramesh S. Iyer 341 vi Downloaded from Cambridge Books Online by IP 128.122.149.154 on Mon Mar 18 17:35:49 WET 2013. http://ebooks.cambridge.org/ebook.jsf?bid=CBO9781139135047 Cambridge Books Online © Cambridge University Press, 2013 Contents Case 96 Systematic review of elbow injuries Case 100 Non-accidental trauma: neuroimaging Claire K. Sandstrom 344 RameshS. Iyer 366 Case 97 Pelvic pseudofractures: normal physeal lines Case 101 Non-accidental trauma: skeletalinjuries Claire K. Sandstrom 351 Ken F.Linnau 371 Case 98 Hip pain in childrenMatthew H.Nett 358 Case 99 Common pitfallsin pediatric fractures: ones Index 375 not to miss RameshS. Iyer 360 vii Downloaded from Cambridge Books Online by IP 128.122.149.154 on Mon Mar 18 17:35:49 WET 2013. http://ebooks.cambridge.org/ebook.jsf?bid=CBO9781139135047 Cambridge Books Online © Cambridge University Press, 2013 Contributors RobertB. Carr, MD Ken F. Linnau, MD, MS Clinical Instructor in Neuroradiology Assistant Professor Department of Radiology Department of Radiology Massachusetts General Hospital University of Washington Harvard Medical School Seattle,WA, USA Boston,MA, USA MichaelJ. Modica,MD Joel A. Gross, MD, MS Fellow in Neuroradiology AssociateProfessor Department of Radiology DirectorofEmergencyRadiology Massachusetts General Hospital DepartmentofRadiology Harvard Medical School UniversityofWashington Boston MA, USA Seattle,WA,USA MatthewH. Nett, MD Martin L. Gunn, MBChB, FRANZCR Clinical Instructor in Musculoskeletal Radiology Associate Professor Department of Radiology Department of Radiology University of Wisconsin University of Washington Madison,WI,USA Seattle,WA, USA Claire K.Sandstrom, MD Ramesh S. Iyer, MD Acting Assistant Professor of Radiology AssistantProfessor Department of Radiology DepartmentofRadiology University of Washington SeattleChildren’sHospital Seattle,WA, USA UniversityofWashington Seattle,WA,USA RandyK. Lau, MD Acting Instructor Department of Radiology University of Washington Seattle,WA, USA. viii Downloaded from Cambridge Books Online by IP 128.122.149.154 on Mon Mar 18 17:36:06 WET 2013. http://ebooks.cambridge.org/ebook.jsf?bid=CBO9781139135047 Cambridge Books Online © Cambridge University Press, 2013 Preface “Toseewhatisinfrontofone’snoseneedsaconstantstruggle.” Unfortunately, false-positive interpretations in radiology GeorgeOrwell,fromtheessayInFrontofYourNose,1946. have been identified as a significant cause of error, leading to The rise of Emergency Radiology as a discrete subspecialty unnecessaryinvestigationandtreatment,increasedhealthcare over the last 25 years, and in particular in the last decade, costs, delays in appropriate management, and litigation. And has unquestionably led to the more timely recognition of that is not to mention the embarrassment of getting a case life-threatening illnesses and injuries, expedited appropriate wrong in front of one’s colleagues. management, and improved clinicaloutcomes. ThisbookfollowstheoutstandingstructuresetbyDr.Fergus The need for rapid decision making and management in Coakley in the first book of this series: Pearls and Pitfalls in patients who present with acute illnesses makes it especially Abdominal Imaging. Each “case” includes a short synopsis of important that radiologists recognize not only the typical the imaging appearances, importance, clinical scenario, and findingsofdisease,butalsomimickersandunusualdiagnoses. differentialdiagnosis,plusakeyteachingpoint.Thisisfollowed Aswithothersinthisseries,theaimsofthisbookaretohelp by a number of images that illustrate the pearl, pitfall, or the radiologist to discern the abnormal from the normal, to differential diagnosis. Where there are several variants on a identify imaging artifacts that simulate disease, and to make theme (for example, accessory ossicles), images were chosen subtle but important diagnoses that might otherwise go toformamini-atlasofvariants. unrecognized. Thebookisintendedmoreasabench-sidereferencethana The growth of imaging utilization in the emergency book that should be read from cover-to-cover. As such, some department over the past 10 years has been enormous. ofthedescriptionsarebriefandtothepoint.Wehavetriedto This is particularly so for MDCT. CT is now used in the includecasesthatrepresentthegamutofdiagnosesthatmight emergency department not only as a way to resolve clinical be encountered in a busy emergency radiology practice that enigmas, but also as a screening tool for a number of condi- includesahighvolumeoftraumaandpediatrics.However,by tions, such as cervical spine trauma, pulmonary embolism, necessity, cases that are either too rare, of limited clinical and suspected appendicitis in adults. Quite rightly, the importance, or unlikely to cause diagnostic confusion have expectations our clinical colleagues have of radiologists con- been excluded. tinuetogrowwiththeirincreaseduseofcompleximagingfor In summary, unlike most reference books on the topic of acute patient care. Radiologists are now expected to provide EmergencyRadiology,thisbookshouldprovideguidancewhen real-time,accuratediagnoses,24hoursperday,365daysper youseeapuzzlingcase,andhelpyoudetermineifitissimplya year,andinmanycases,discusscasesbeforeandafterimages borderland of normal, or an important but less recognized are acquired. diagnosis. ix Downloaded from Cambridge Books Online by IP 128.122.149.154 on Mon Mar 18 17:36:27 WET 2013. http://dx.doi.org/10.1017/CBO9781139135047.001 Cambridge Books Online © Cambridge University Press, 2013