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MI10 Medical Imaging
Abdominal Imaging Toronto Notes 2019 Tubes, Lines, and Catheters
• ensureappropriateplacementandassesspotentialcomplicationsoflinesandtubes
• avoidmistakingaline/tubeforpathology(e.g.oxygenrebreathermaskforpneumothoraces)
Central Venous Catheter
• usedforfluidandmedicationadministration,vascularaccessforhemodialysis,andCVPmonitoring
• tipmustbelocatedproximaltorightatriumtopreventinducingarrhythmiasorperforatingwallof
atrium
■ if monitoring CVP, catheter tip must be proximal to venous valves
• tipofwell-positionedcentralvenouscatheterprojectsoversilhouetteofSVCinazonedemarcated superiorly by the anterior first rib end and clavicle, and inferiorly by top of RA
• courseshouldparallelcourseofSVC;ifappearstobendasitapproacheswallofSVCorappears perpendicular, catheter may damage and ultimately perforate wall of SVC
• complications:pneumothorax,bleeding(mediastinal,pleural),airembolism
Endotracheal Tube
• frontalchestfilm:tubeprojectsovertracheaandshallowobliqueorlateralchestradiographwillhelp determine position in 3 dimensions
• progressivegaseousdistentionofstomachonrepeatimagingisconcerningforesophagealintubation
• tipshouldbelocated4cmabovetrachealcarina(avoidsbronchusintubationandvocalcordirritation)
• maximuminflationdiameter<3cmtoavoidnecrosisoftrachealmucosaandrupture;ensurediameter
of balloon is less than tracheal diameter above and below balloon
• complications:aspiration(parenchymalopacities),pharyngealperforation(subcutaneousemphysema,
pneumomediastinum, mediastinitis)
Nasogastric Tube
• tipandsideportshouldbepositioneddistaltoesophagogastricjunctionandproximaltogastric pylorus
• radiographicconfirmationoftubeismandatorybecauseclinicaltechniquesforassessingtipposition may be unreliable
• complications:aspiration(parenchymalopacities),pneumothorax
Swan-Ganz Catheter
• tomonitorpulmonarycapillarywedgepressureandestimatediastolicfillingofleftheart.
• tipshouldbepositionedwithinrightorleftmainpulmonaryarteriesorinoneoftheirlarge,lobar
branches
• iftipislocatedmoredistally,increasedriskofprolongedpulmonaryarteryocclusionresultingin
pulmonary infarction or, rarely, pulmonary artery rupture
• complications:pneumothorax,bleeding(mediastinal,pleural),airembolism
Chest Tube
• indorsalandcaudalportionofpleuralspacetoevacuatefluid
• inventralandcephaladportionsofpleuralspacetoevacuatepneumothoraces • tubemaylieinfissureaslongasfunctioning
• complications:bleeding,infection,lunglaceration
Abdominal Imaging
Abdominal X-Ray
Indications
• acuteabdomen:bowelperforation,toxicmegacolon,bowelischemia,smallbowelobstruction,large bowel obstruction
• chronic symptoms: constipation, calcifications (gallstones, renal stones, urinary bladder stones, etc.) • notusefulin:GIbleeds,chronicanemia,vagueGIsymptoms
Anatomy
• abdomendividedinto2cavities
■ peritoneal cavity: lined by peritoneum that wraps around most of the bowel, the spleen, and most of
the liver; forms a recess lateral to both the ascending and descending colon (paracolic gutters)
■ retroperitoneal cavity: contains several organs situated posterior to the peritoneal cavity; the contour
of these can often be seen on radiographs
Figure 15. CXR showing well-positioned central venous catheter
3 Views of AXR
• Erect/Upright
• Supine
• Left lateral decubitus