CT Guided Procedures And Interesting Cases Stephen Kim, MD Diagnostic and Interventional Radiology
CT guided procedure benefits Precise lesion targeting Clear image guidance for needle placement Immediate post procedure diagnostic information Post procedure bleeding Pneumothorax
CT guided procedure risks Radiation exposure Strive for low dose radiation Typically non contrasted imaging Sedation and anesthesia
Types of CT guided procedures Drainage catheter placement Chest Abdomen / Pelvis Biopsy Lung Solid Organ Lymph nodes Bone Tumor ablation Vertebroplasty Embolization
Procedure Preparation Team members Radiologist and other doctors Procedure technician Sedation team Pathology team CT technician Clean and organized CT room No known emergent CT cases Time out Type of procedure Laterality Patient identifiers Allergies
Tips Prior to patient transport, ask the performing MD about laterality, patient positioning, and lesion location Supine, prone, decubitus Have 2 or more additional people help load the patient onto the CT table Minimize patient movement - secure the torso and extremities with straps Make space for both the sedation nurse and MD equipment Disposable versus reusable grid for planning Tape with a string of paperclips work well Breathing instructions per MD preference Be aware of the sterile field
Additional Tips Make sure the room has cleared before each CT scan Make sure everyone is wearing lead if CT fluoro used Quickly manage the CT scanner buttons to move the patient in and out between needle advancements Have appropriate emergency backup ready (ex. anesthesia team, chest tube, code activation)
Procedure Tools
CT Guided Procedures And Interesting Cases
CT guided Biopsy CT is commonly utilized for biopsy Lung, soft tissue, bone Skin entry site identified Needle advanced through tissue into the lesion Lesion sampled Risks: Pneumothorax, bleeding, radiation exposure
Plan and Advance Planning Scan Guidance Scan
Low Dose CT Lung Biopsy Diagnostic Chest CT Dreyer Low Dose Chest CT Focused CT Lung Bx DLP ~800-1000 mgy*cm ~400 mgy*cm ~50 mgy*cm
Low Dose CT Concept IR may use many repeated scans during positioning of biopsy needles and acquisition of samples but want to use minimal radiation dose Lung and bone have high intrinsic contrast contrast-to-noise (CNR) maintained despite low signal to noise (SNR) Nodule vs Lung - Take advantage of this Soft tissue biopsy needs more dose, less intrinsic contrast Liver, pelvic biopsy Axial vs. helical use axial for less overscan and less dose
Axial scan (not helical) 2.5 mm (do not need thinner) For needle placement ma Standard Algorithm Maintain signal to noise GE Dose modulation. Auto ma + Smart ma Scans assuming oval body shape, ma changes from Shoulder to lung to mediastinum to lung base SS100=ASIR100% Dose reduction protocol by Image reconstruction Uses noiser data.
Tolerate lots Of noise bc ASIR and IC Auto ma and Smart ma on Very high noise index (lung = high intrinsic contrast [soft tissue / air] or bone) 10 is mimimun ma allowed 50% dose reduction Manual ma is low in case of problem like invalid scout)
Very low estimated dose 80 images is 20 cm range at 2.5 mm thick
Low Dose CT Lung Biopsy Scan 1 Scan 2 Scan 3 Scan 4 Scan 5
CT Biopsy and Ablation of solid organ masses
Image-guided Spine Procedures For Relief of Pain Severe Back Pain Facet Joint Selective Nerve Root Block Radiofrequency ablation of a painful bone tumor Spine compression fracture and Vertebroplasty
Biopsy Vertebroplasty Bone tumor ablation Facet Injection
Sacral Insufficiency Fractures
Aortic Aneursym Graft and Endoleak Repair
CT Guided Endoleak Embolization
Post Liquid Embolic
Take Home Points 1. Prior to the patient's arrival, confirm with the performing physician laterality, patient positioning, lesion location 2. Minimize patient movement - secure the torso and extremities with straps 3. Make sure the room is clear when CT scanning 4. Be aware of the sterile surgical field 5. Have appropriate emergency backup (ex. anesthesia, chest tube, code activation)
Utilize your institutions low dose technique Small lesions may need increased ma to see better Start with larger cuts 5mm -> may need thinner 2.5mm Gantry tilt may be needed to align with the needle trajectory CT Fluoro Overall more radiation. Use lead protection
Thank You