Abdominal Imaging and Intervention
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Abdominal Imaging and Intervention Abdominal Imaging and Intervention Document Transcript

  • ABDOMINAL IMAGING AND INTERVENTION GASTROINTESTINAL Abdominal Imaging and Intervention Gastrointestinal ProceduresPatient Positioning: Positioning in GI examinations always refers “to the table.” even when spotfilms are obtained. Thus, RPO means that the patient’s right flank is against the table top. Fluoroscopy Oral Cholecystogram Hall’s Double Contrast Enema (“Double Dose” Gallbladder) Technique 0.5 mg Gucagon LiquidPolibarTechnique 1. Tube inserted, balloon not used unlessSurvey KUB - if GB is visible, proceed as follows: necessary. º ConedAP 2. GlucagongivenI.V. º ConedRPO 3. Patient prone - barium instilled to just be- º Upright compression spot films. yond the splenic flexure with patient still prone. Drain out as much barium as will Examination usually ends here. come. º Fatty meal, decubitus films to be 4. Patient prone - pump air in and then rotate added at discretion of radiologist. patient through patient’s right side to supine position. º If gallbladder opacification is 5. Patient supine - barium should have reached inadequate, Sodium Oragraffin may the hepatic flexure and be dripping down the be given orally the same day. right colon. 6. Patientsemi-upright-bariumgoesdownright colon, and put in more air. SPOTS of the hepatic, spenic flexures and sigmoid. Barium Enema 7. Table down with patient supine - SPOT (Colon) cecum and T.I. and RESPOT sigmoid in su- pine and LPO projections.Technique 8. Overhead: APBarium Suspensions: PA PA angled rectum Prone cross table rectum s Full column colon - 20% w/w L decubitus R. decubitus Add one packet as per radiologist. º Redundant colon add both obliques ºPost evacuation films are not routine s Air contrast colon - 65% w/w but may always be added; especially when the right colon is a problem. s Premedicated with 0.5 mg of R UIE O TN O TO A PI NL OUTP TIENT A glucagon IV. VIEWS VIEW P A Chassard-Lapine PAangle P Angle A AP LateralRectumThe routine overhead views (Hi - kVp: 110 KV) to be ob- LO P RO P LO Ptained for conventional barium studies are: LateralRectum LPOAngle RO P BE-FullColumnPre-Evacuation AP post evacuation LPO post evacuation PA 379
  • CLINICAL PRACTICES UGI Series (Stomach) 4. Patient supine. hSPOT - Air contrast views stomach: Barium Suspensions: UGIandSBFT, Duodenogram (85%w/w* 250% w/ )w EZ HD Barium for double contrast EZPaque Bariumforsinglecontrast(40%-75%w/w) Patient supine (body) Routine Overhead Views The routine overhead views to be obtained for conventional barium studies are: UGI (110kVp) Patient LPO RO A (antrum) (bulb if present) P A AP - 14” x 17” LO P Patient RPO (Schatzki view) High lesser curve “enface” and posterior wall of body. *weight for weight Erect LPO Also position to check for GE reflux. Hall’s Double Contrast Upper GI Ingredients: Packet of E-Z gas granules 10 cc water FullcontainerE-Z HDbarium Patient RAO (fundus) Positions refer to table: 1. Patient upright - patient swallows E-Z granules and water. hPatient urged not to burp. Patient RAO 5. Examine esophagus with regular barium - checking 2. Patient still upright LPO swalows barium continu for esophagus motility, hiatal hernia, etc. ously . hFluoro esophagus. hSPOT - Air contrast distended esophagus. 3. Table down with patient prone. h SPOT-PRONECOMPRESSION: Stomach, hSPOT of cervical esophagus and GE junction. antrum, bulb if present. Views of bulb-filled RAO with compression. Patient LPO Patient rolls to supine through the left side, 6. Air bulb LPO and LAO include some antrum and C mucosal coating is checked. If not adequate, turn loop. patient to prone and back through left side.380
  • ABDOMINAL IMAGING AND INTERVENTION GASTROINTESTINAL7. Semi-uprightcompression Enteroclysis Enteroclysis is a special procedure performed to Compression of antrum, lesser evaluate the small bowell. The usual indications are to curve,duodenum. determine the source of occult bleeding, recurrent obstructive symptoms, or the extent of Crohn’s disease. Overheads: PA, RAO stomach It is not intended to be a primary exam. RAO drinking esophagus FullAP Preliminary studies should include a normal upper GI seriesorendoscopy,normalbariumenemaorcolonoscopy, Miscellaneous Maneuvers and Views: and normal small bowell follow through. Since intuba- hBoth obliques of the esophagus. tion to the ligament of Treitz region is a requirement, any gastric surgery such as Bilroth II which would make hAngled view of the stomach RAO to head intubation difficult is a relative contraindication. Prior LPO to feet. discussion with radiologist is required before scheduling the exam. hCross table view of stomach (lateral). hUpright view of fundus. Equipment: Lidocainejelly Cetacaine spray hProne LAO view of antrum-anterior wall Well lubricated nasogastric tube of stomach. Well lubricated guide wire Tongue depressor hVarices study - Esophotrast or HD 5000 Glass of water with a straw barium, multiple coned down oblique views Several emesis basins of the collapsed GE junction. Enteroclysispump Barium bag filled with pre-chilled 1500 - 2000 cc Methylcelluose. Approximately 200 cc of medium density Small Bowel barium drawn up in appropriate syringes.TechniqueAfter steps 1 - 5 of Upper GI Procedure Give 10.0 mi of gastrograffin in 8 ounces of barium suspension (55% w/w). Scout film. Take PA films (14” x 17”) q 30 min. until column Explain intubation and rest of procedure to patient. reaches cecum and them obtain spots of terminal Intubation: ileum. Cetacaine spray to the back of the throat. Xylocaine jelly into the nose. With patient sitting on the edge of the table and his/her Barium Swallow (Esophagus) head being supported by the technologist, insert tube. Pass tube into the esophagus as the patient drinksTechnique water.Barium Swallow: Upright drinking liquid barium. If any resistance or problems are encountered, the pa - PA tient can be placed on his/her right side on the fluoro table Lateral and the tube passed through the hypopharynx under fluor- Obliques oscopic visualization.Use of Glucagon: Once the tube is in the stomach, insert the guidewire toThis is a useful adjunct whenever smooth muscle spasm or within 1 - 2 inches of the end of the tube. Pass the tubestenosing lesions of the alimentary canal are encountered. to the pylorus by putting the patient in the LPO positionThus it is used in evaluation of the esophagus, stomach, duode- and sliding the tube along the greater curvature.num, small intestine, common bile duct and colon. Hopefully, the tube will pass through the pylorus. If LPO positioningdoesnotaccomplishthis,tryRAOpositioning.The usual dose in the upper GI system is .1 - .5 mg and in thelower GI .5 - 1 mgs 1.0 mg/in 1 ml administered intravenously. Once the tube is in the duodenum, advance the tube withSevere diabetes and tachy arrhythmia are relative the guidewire as far as possible. Ideally, the tube shouldcontraindications. be beyond the ligament of Treitz. 381
  • CLINICAL PRACTICES Technique T - Tube Cholangiogram 1. Instill 150 - 200 cc of the barium into the small Points of Technique bowel. Use slightly less for smaller patients and slightly more for larger patients. Must attempt to achieve air-free fluid filled system. 2. Pump in the Methylcellulose. During instillation, Avoid excessive pressure and overfilling (danger of try to keep the Methylcellulose from refluxing retrograde infection). into the stomach by keeping the patient in an LPO or left lateral position. Sterile precautions. 3. As soon as dilatation of the proximal bowel is obvious, start taking multiple spot films with Technique compression. 1. Patient on left side, right side up with drainage 4. After approximately 1500 cc of Methylcellulose tube hung so bile drains back and fills system. has been instilled and/or barium has reached the terminal ileum, overheads can be obtained. PA, 2. Into T-tube, as close as possible, to outside end AP, and angled PA views to see the small bowel insert a scalp vein needle or small bore needle loops in the pelvis are suggested. connected to a diluted contrast-filled syringe (renograffin 60% and diluted 50% with saline 5. Subsequent spot films and another series of or Urovist, or Conray) via straight plastic tube overheads can be performed as needed to see leader. the entire small bowel. 3. Clamp the T-tube distal to the point of needle Hints: insertion with a hemostat. Also clamp over the Proceed quickly since reflux of Methylcellulose needle itself with another hemostat. into the stomach causes vomiting and once 4. With syringe slightly elevated, aspirate bile and Methylcellulose reaches the colon it can cause allow any air bubbles to rise to the top of the diarrhea. fluid level in the syringe. Tapping the tube will help occasionally. Air bubbles may ruin the ex- After the procedure explain to the patient that amination. diarrhea is normal and remind the patient not to 5. Allow the contrast to run in by gravity, or, if drink for several hours because of the local an- necessary, inject slowly and in small increments, esthesia to the pharynx. obtaining sequential spot films. Overhead Views (Optional) Films coned to right upper quadrant (75 kVp) Supine RPO: Inject 2 - 3 cc immediately prior to film. AP: Inject 2 - 3 cc immediately prior to film.382
  • ABDOMINAL IMAGING AND INTERVENTION GASTROINTESTINAL Computed Body Tomography CBT - General Guidelines Pancreatitis Evaluation for PancreatitisPreparation 1. Oral contrast when possible.BowelOpacification 2. IV contrast: only for preoperative mapping of perfusion of the pancreatic bed. 400 - 600 cc of dilute Gastrograffin (¼ oz in 10 oz of water) p.o. in 2 divided doses, 6 - 8 hours and Dynamicscanningfollowing bolus of 30-50 cc Reno 60 is employed. ½ hour before exam for: GITract Interventional 3. 5 x 8 mm thick cuts from the xyphoid Pancreas through the pancreatic bed. Retroperitoneum 10 or 15 mm intervals may then to the Pelvis level of the iliac crest (to evaluate caudal An enema (same dilute Gastrograffin solution) may extent of phelgmon, etc.). be helpful in some cases. Evaluation of Jaundice Due to ExtrahepaticPhotography Biliary Obstruction Soft tissue, lung and liver windows at the appropri- 1. Unenhanced, 5 mm thick scans to identify ate levels. the transition zone from dilated to narrow duct. Bone windows only if lesions are detected on 2. Enhanced scans using dynamic sequence, console. 5 mm thick cuts, every 8 mm from just above the transition zone to below this area.Technique 3. If unenhanced scans show no obvious transi- These are general guidelines. tion, use bolus infusion, dynamic sequence Many examinations will require a tailored approach 5 mm thick cuts at 8 mm intervals, from the level of the porta through the pancreas.Liver 4. Use smaller area of view (smaller pixel size, Evaluation of Neoplasm/metastatic Disease more resolution). 1. Oral contrast-dilute gastrograffin. 5. Complete liver and pancreas scanning, as 2. Test cut to identify dome of liver. indicated. 3. IV contrast 120 cc Reno 60% bolus indynamicmode. Pelvic Malignancies 1. Oral contrast-dilute gastrograffin is given ini-Pancreas tially 4 - 6 hours before the examination to ensure distal bowel opacification. Evaluation for Pancreatic Carcinoma 1. Oral contrast-dilute gastrograffin. Dilute gastrograffin enemas may be needed in some cases. 2. IV contrast: rapid bolus infusion (Reno 60) mayhelpidentifysmalleradenocarcioma(gen- 2. IV contrast: not needed in all cases. May be erally do not enhance to the degree of normal useful in distinguishing lymph nodes from ves- pancreatic tissue); sels, defining the ureters and opacifying the bladder (some prefer to evaluate the natively IV contrast also helpful in separating vascu- distended bladder prior to contrast). lar structures from the pancreas (i.e. splenic vein). 3. Other techniques sometimes employed: 3. Collimation variable depending on the nature Vaginal tampons may be helpful in of the problem; generally 5 mm. evaluation of cervical carcinoma. 4. Select smaller area of view (small pixel size, Air instillation into the urinary more resolution). bladder for air contrast. 5. Liver scanning for evaluation of metastastic 4. Collimation/scanning intervals: disease. The pelvis is scanned with 5 x 8 mm cuts. 5 mm cuts at 8 mm intervals may be used as in GU. 383
  • CLINICAL PRACTICES Stomach Suspected Retroperitoneal 1. Clear liquid after midnight until CT scan. Hemorrhage 2. Large volumes of oral contrast (dilute 1. Generally, oral and IV contrast are not gastrograffin to ensure adequate distension; needed. “fizzies” may also be useful. 2. Scan using 10 mm contiguous cuts from the 3. IV glucagon may be used as a hypotonic diaphragmatic level through the pelvis. agent. 4. Different patient positions may be useful for evaluation of specific areas of the stomach. Lymphoma Stage 5. If findings suspicious for neoplasm, evalu- 1. Oral contrast-dilute gastrograffin: optimal ate liver for metastatic disease. bowel opacification. 2. Rectal contrast: may be necessary for ques- Intra-Abdominal or Pelvic Abscess tions of pelvic involvement. 1. Oral contrast-dilute gastrograffin: opacifi- 3. IV contrast: bolus scan may be needed in cation of the entire gastrointestinal tract is selected cases to distinguish lymph nodes critical. from vascular structures. Also, patients with a paucity of retropeeritoneal fat may be more Ideally 600 - 900cc of dilute gastrograffin confidently evaluated with a bolus combina- solution is given in divided doses at 12, 6, tion. In most cases, however, this is not nec- and 1 hour prior to CBT. essary. Some patients, especially those with ileus 4. Scan with 10 mm contiguous cuts from the or obstruction, require more lengthy bowel diaphragmatic level through the pelvis. preparation. Placing the patient on the right side may help facilitate gastric imaging. Trauma 2. Rectal contrast: may be necessary, espe- See Emergency Radiology section of this manual. cially with pelvic pathology. 3. Scanning using 10 m thick contiguous im- ages from diaphragmatic level through the pelvis. Repeat scanning through specific areas of question may be necessary, for instance to differentiate unopacified bowel loops from fluid collections. 4. Percutaneous sampling may be necessary to confirm that a fluid collection is infected. Magnetic Resonance Imaging MRI Imaging Options Protocol programs specifying all imaging nal imaging technique. Consultation with options for each pulse sequence are avail- an Abdominal radiologist is advisable prior able from MRI. Rapid improvement in to scheduling such an examination. hardware and software options require fre- quent review of current specifications. Abdominal survey MRI generally results in an incomplete and suboptimal MRI tailored to a specific clinical situation examination. can be used as a problem-solving abdomi-384
  • ABDOMINAL IMAGING AND INTERVENTION GASTROINTESTINALLiver MR (Non-Vascular) MR of AdrenalsTechnique Technique Body coil. Coronal localizer, multislice breath hold Body coil. Coronal localizer, multislice axial T1 SE axial T1 GRE with fat-water in phase, breath-hold and T2 SE or FSE images as programmed. T1 GRE with fat-water opposed phase, and axial non- fat saturated (non-FS) double echo (TE 80, 160) T2 Breath hold T1 GRE with fat and water in and out SE or FS T2 FSE images as programmed. ofphase(FMPSPGR). Discretionary Discretionary Second T2 sequence (SE or FSE), T1 SE, dynamic Coronal or sagittal T1 SE or T2 FSE, especially for GREimagingwithGdchelate(0.1mmol/kg),especially suspected pheochromocytoma. for characterization of equivocal lesions and for de- tection of primary liver tumors. Phased array multicoil may be used in thin patients. In critically ill or uncooperative patients consider T2 For characterizing small adrenal masses liver proto- EPI. col may be substituted for adrenal protocol. Phased array multicoilmay be used in thin patients. Renal MR (Non-Vascular)Spleen MR (Volumetric) TechniqueTechnique Body coil. Coronal localizer. Axial FS T2 FSE, FS T1SE,T1GRE. Body coil. Coronal localizer. Coronal T1 SE and axial (or 3-D) T2 FSE. Discretionary DynamicT1GREwithGdchelate(0.1mmol/kg),de- Trace spleen on each slice, measure area. layed FS T1 SE, axial TOF (for staging venous Multiply by slice increment and add to get volume. invasion).MR Cholangiopancreatography Pelvic MR for Prostate(MRCP) Technique Insert endorectal prostate coil. Using body coil, ob-Preparation tain coronal localizer and axial T1 through renal hila Fasting - six hours. to pelvis.Technique Using endorectal coil, obtain through prostate sagit- Phased array multicoil. Ultra-long TE thin section tal localizer, then axial T1 SE and axial and coronal coronal FSE images acquired either with segmented T2FSE. source breath holding or during quiet respiration. Discretionary Source and MIP images displayed. Endorectal coil sagittal T2 FSE. Discretionary 3-D T2 FSE if available; axial images (especially for stones), EPI. Pelvic MR for Uterus PreparationPancreatic MR Glucagon1mgs.c.immediatelypriortoimaging(omitPreparation forIDDM). Fasting - two hours. Technique Phased array multicoil. Sagittal localizer. Axial T1Technique SE, sagittal, long and short axis T2 FSE. Phased array multicoil (thin patients) or body coil. Coronal localizer. Axial FS T2 FSE, FS T1 SE, dy- Discretionary namic T1 GRE with Gd chelate (0.1mmol/kg). Sagittal or coronal T1 GRE, dynamic sagittal T1 GRE with Gd chelate (0.1mmol/kg), delayed FS T1 Extended coverage through liver; MRCP; post-con- SE (especially for tumor staging). trast FS T1 SE; MR venography. 385
  • CLINICAL PRACTICES Pelvic MR for Ovaries Rectal MR Preparation Preparation Glucagon1mgi.m.immediatelypriortoimaging(omit Fleet’s enema 3-4 hours prior; glucagon 1mg i.m. forIDDM). immediately prior to imaging (omit for IDDM). Technique Technique Phased array multicoil. Coronal and axial T1 SE, InsertMRInnervu™endorectal/colorectalcoil(NOT axial and sagittal T2 FSE, dynamic T1 GRE with Gd prostate coil). Coronal localizer (body coil). chelate (0.1mmol/kg). Axial T1 SE and FS T2 FSE through rectum Discretionary and oblique longitudinal FS T2 FSE through AxialorcoronalFST1SE(forT1-brightlesions). tumor and axis of coil. Interventional Procedures Division Protocol Fine Needle Aspiration Biopsy (InformedConsentRequired) Direct dicusion between the requesting physician and a Technique radiologist in the Abdominal Tumorlocalization-US,CT,Fluoro. Division is required to set up Depth measurement and needle path selection. the interventional procedures 22g needle prepared for puncture; in some instances described below. larger bore needles (14-18, 20 g) may be employed. At that time, indications and Fine needle puncture of tumor - no effort to avoid viscera or vessels. goals for the procedure, handling of specimens, and patient after- Several core biopsies obtained with 15-20g needle, care should be agreed upon. placed in tubes with 2 cc sterile saline and sent to Cytology. Cytology will separate cores and send to Pathology for sectioning. The supernatant is spun Because of the coordination for Cytology. required between imaging and Several aspirations also obtained and sent to intervention, marking the skin Cytology in saline. for a subsequent unguided pro- cedure and guiding by imaging Four glass slides made by the cytotechnologist and rapidly placed in preservative solution. a percutaneous interventional procedure performed by a non- Four to five passes are sufficient. imaging specialist are excluded Request for special stains or frozen sections (i.e. from the description below. lymphoma) might be indicated. Check with Pathology regarding proper handling. Abdominal interventional proce- If large needles are employed, an effort is made not dures are the subject of continu- to transgress bowel. ing research and re-evaluation.386
  • ABDOMINAL IMAGING AND INTERVENTION GASTROINTESTINAL INTERVENTIONAL PROCEDURES Fine Needle Percutaneous Specimen Processing Transhepatic Cholangiography (FNPTC) (InformedConsentRequired)Biopsy trays are kept in the White 2 Preparation PT, PTT, platelet count; bleeding time if indicated (i.e. Bx Carts in the US/CBT area. ASAuse). Preprocedure antibiotics: 70-90% of patients with bil-An assortment of biopsy needles, iary obstruction due to calculi, and 25-35% with malig- 50% alcohol, lab requisitions, nant obstruction, have infected bile. The majority of these xylocaine, heparin, culture, are polymicrobial infections. Thus, antibiotics (most com- monly ampicillin and an aminoglycoside, are begun be- etc. are in the cart. fore, the procedure.Cytology specimens are to be on For penicillin - sensitive patients, use vancomycin IV. frosted slides in appropriate Premedication - sedatives, analgesics. media supplied by Cytology. Local anesthesia (Lidocaine) A dry syringe is used for Technique cytologic slides. Puncture Site With fluoroscopy, choose a point in the midaxillaryoPathology - Formaldehyde 4% (tissue line, several cm below costophrenic sulcus in maxi- or bone only). mal inspiration. In older patients this will usually be the 8th - 9thBacteriology - Specimens in syringe interspace, and in younger patients the 10th or 11th (no air space), cap with white interspace. “dead head” plugs. A 22 gauge Chiba needle is used, oriented 30 vertical to tabletop.Label each bottle or syringe with During suspended breathing, advance needle in smooth, uninterrupted motion, until tip lies slightly stamped addressograph label. to right of T11 - T12. Remove stylet attach extension tubing and contrastSpecimens must be carried by a syringe (Conray 30%); eliminate air bubbles from reliable person to designated the system. lab area immediately. Person- Contrast injected incrementally under fluoroscopic nel are available for delivering guidance during gradual withdrawal of needle specimens. (1 - 2 mm increments). Site of contrast deposition determined fluoroscopi- cally (i.e. parenchyma, artheries, veins, lymphatics,Cytology specimens should be in lab ducts). before 4:00 p.m. for best results. Multiple passes may be required to cannulate the biliary system.Any specimen with blood should be Additional passes follow a fan-shaped orienta- in heparinized solution to pre- tion. vent clotting for better smears. Left duct puncture - via subxyphoid approach (ultrasound useful to guide subxyphoidSpecimens are not to be stored in a approach). subrefrigerator for later delivery. When a bile duct is cannulated: contrast is injected o slowly; this will accumulate in dependent portion ofEither physician, nurse, or tech- biliary system. nologist or transporter hand Tilting table 45 upright, and rotating patient to LPO or (L) lateral position are useful maneuvers to carries the specimen to the promote more complete filling without over distend- laboratory immediately. ing the biliary system with contrast. 387
  • CLINICAL PRACTICES Percutaneous Biliary Percutaneous Abscess Decompression (PBD) and (InformedConsentRequired) Fluid Drainage Preparation (InformedConsentRequired) PT, PTT, platelet count; bleeding time if indicated (i.e. ASA use). Preparation Preprocedure antibiotics: 70-90% of patients with biliary Obtain bleeding parameters and take measures to obstruction due to calculi, and 25-35% with malignant correct abnormalities. In unusual cases, 20 or 22 obstruction, have infected bile. The majority of these are gauge aspiration can be performed in the setting of polymicrobial infections. Thus, antibiotics (most com- an uncorrectable bleeding disorder. monlyampicillinandanaminoglycoside,arebegunbefore, the procedure. For penicillin - sensitive patients, use vancomycin IV. Technique Premedication - sedatives, analgesics. Selecting the Access Route This is the most important aspect of aspiration/drain- Local anesthesia (Lidocaine) age of abscess and other fluid collections. CT, ultra- sound,andlesscommonlyfluoroscopyareemployed. Technique Some guiding principles follow: PerformFNPTC; identify site of obstruction and Avoid transversing bowel or uninfected organs. choose duct for PBD. This duct should have a rela- Avoid large vessels. tively horizontal orientation. Avoid contaminating sterile spaces (peritoneal, pleural cavities) and sterile collections. Fluoroscopic placement of a 22 gauge needle for duct entry, through which an 0.018 guide-wire is placed, Access routes which violate the above principles may followed by a 4-5 Fr dilator. be necessary in some cases. Discuss with staff before using these routes. This system may be more useful for less dilated or Preferred access routes for some specific areas stenotic ducts. An alternative system employs follow: sheathed needle placed into a dilated duct with Retroperitoneal collections - drain via retro- peripheral duct entry (multiple sizes: 22 - 18 gauge). peritoneum when possible. Subphrenic abscess or superiorly located liver Remove stylet and withdraw sheath until bile drips abscesses - angled approach to avoid pleural through sheath. contamination. Presacral abscesses - transgluteal or transvagi- Place guidewire (usually followed by successful nal /transperitoneal approach. crossing of the obstruction). Diagnostic Aspiration Note: an alternative system employs a 22 guage needle. Technique Generally, a 22 gauge needle is used initially. If cholangitis is present, place drainage catheter with a minimum of contrast injection and manipulation (do Only 5-10 cc is aspirated for diagnostic purposes, to not vigorously attempt to cross obstruction). allow a “target" for catheter drainage. An 18 or 20 g needle may be necessary to aspirate Initial catheters include 7 Fr pigtail or 8 Fr Ring. No viscous material. side holes should lie outside bile ducts, in hepatic parenchyma, outside of the liver or in vessels. Specimen Processing Gram stain (STAT), aerobic and anerobic cultures, and Post Procedure Management a cell count (STAT) are ordered. Hct, vital signs Other tests might be ordered in special circumstances Antibiotics for 3 days (i.e., amylase of suspected pseudocyst, cytology if suspected necrotic/cystic tumor creatinine in sus- External drainage for 3 days (tube unclamped; pected urinoma). record bile drainage) Catheter irrigation q 2-6 hr depending on extent of hemobilia.388
  • ABDOMINAL IMAGING AND INTERVENTION GASTROINTESTINAL INTERVENTIONAL PROCEDURES Results of the STAT gram stain and cell count can TrocarTechnique be categorized as follows: This involves placement of the catheter in tandem Bacteria and white cells - Abscess. with the fine needle used for aspiration. Pigtail catheters (6-10.2 Fr) Mueller catheters White cells but no bacteria - This may be seen (10-16 Fr) or sump catheters (12-14 Fr - useful for in the patient on antibiotics, and may repre- more viscous collections) are generally employed. sent a "sterile abscess"; cultures are always ordered. Coaxial or Seldinger Techniques Bacteria, no white cells: - This can be seen Useful when access route is narrow. in immunocompromised hosts with abscess, but the possibility of bowel contamination Following Drainage should always be considered. Irrigate the cavity with 25 cc aliquots of normal saline until fluid returns clear. No cells, No bacteria: - Sterile collection (cyst, pseudocyst, hematoma, lymphocele, etc.). CTorultrasoundshouldthenconfirmcompletedrain- age; multiple catheters may be required. One may wish to aspirate dry, especially if the collection is in a confined space. A cath- Catheter Care eter is not usually left in such a collection. Irrigate q.4-6 h with 20 cc NS.Drainage Close monitoring of output. Principles include the following: Generally, at 24 hours the cavity is injected under fluoroscopy to assess its site and evaluate for Remove a minimal amount of material with initial fistulae. aspiration to preserve the "target". Patient doing well - slowly advance drain. Side holes of drainage catheter should be in the Patient doing poorly - CT or ultrasound to assess dependent area of cavity. collections; repeat evaluation for fistula. Imaging Guided Pleural InterventionsOverview (InformedConsentRequired)These procedures include diagnostic and Preparationtherapeutic thoracentesis, chest tube inser- Obtain bleeding parameters and take measures totion, and pleural biopsy. Most commonly correct abnormalities if a chest tube or pleuralultrasound is used, but sometimes fluoros- biopsy is to be performed.copy, CT or a combination of modalities is Coags are not required for simple thoracenteses; inrequired. unusual cases, 20 or 22 gauge aspiration can be performed in the setting of an uncorrectable bleed-As with other procedures performed by the ing disorder.Abdominal Division, direct dicussion be-tween the requesting physician and a radi-ologist in the division is required to set up Techniqueone of these procedures. Selecting the Access RouteAt that time, goals of the procedure, han- This is the most important aspect of aspiration/dling of specimens, and patient aftercare drainage of pleural collections.should be agreed upon. 389
  • CLINICAL PRACTICES Diagnostic Aspiration Catheter Care Technique Irrigate q4-24 h with 5-20 cc NS. Patient upright, supported leaning forwardifpatients Use of a three-way stopcock makes this convenient condition permits. butmay violate nursing policy on some units. Check Dcubitus or supine position can be used in debili- with referring physician. tated patients if effusion is large. Close monitoring of output. Generally, a 22 gauge needle is used initially. 1-50 Patient doing well; drainage nil--place on water seal, cc is aspirated for diagnostic purposes, depending wait 12-48 hours, then remove. upon the diagnostic goals. If drainage or biopsy is planned, 5 cc or less should Obtainimmediatef/uCXR. be obtained initially. Biopsy Specimen Processing Usually Gram Stain, culture (including anaerobes), Principles include the following: chemistryredtop(LDH,glucose),hematologypurple Cope reverse cutting needle for slight-moderate top (fluid count), blood gas syringe for pH. pleural thickening and moderate-large pleural Other specimens such as cytology, fungal or the effusion. culture, as required. Standard biopsy technique for marked pleural thick- Frontal CXR obtained and evaluated immediately ening and nil-small pleural effusion. following any pleural intervention. Drainage Cope Needle Technique Principles include the following: Diagnostic aspiration (minimal fluid) and excellent Remove a minimal amount of material with initial skin preparation. aspiration to preserve the "target". Insert cannula with obturator needle. Replace ob- Side holes of drainage catheter should be in turator with cutting needle. the dependent area of cavity. Withdraw assembly at an angle, catching and hold- TrocarTechnique ing pleura. Avoid caudal rib margin. This involves placement of the catheter in tandem with the fine needle used for aspiration. While maintaining countertension, rotate and dvance cannula, shearing specimen into cutting needle. 8 Fr Turkel catheter used for therapeutic aspira- tion, usually into a vacuum bottle. Withdraw cutting needle to harvest specimen, Mueller empyema catheters (10-24 Fr) are employed occluding cannula. forempyema. Coaxial or Seldinger Techniques Following Biopsy Useful occasionally for loculated collections or to Withdraw additional fluid for diagnosis, as required. exchange for a larger catheter. CXR. Following Drainage Attach to pleurevac drawing 20 cm H2O suction. CXR;repeatsonographyorotherimagingas required to confirm adequacy or placement.390