stephen kim, md diagnostic and interventional radiology · tips prior to patient ... shoulder to...
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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
DLP
Diagnostic Chest CT ~800-1000 mGy*cm
Dreyer Low Dose Chest CT ~400 mGy*cm
Focused CT Lung Bx ~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
SS100=ASIR100% Dose reduction protocol by
Image reconstruction
Uses noiser data.
Standard Algorithm Maintain signal to noise
mA
GE Dose modulation. Auto mA + Smart mA
Scans assuming oval body shape, mA changes from
Shoulder to lung to mediastinum to lung base
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)
Tolerate lots
Of noise bc
ASIR and IC
Very low estimated dose
80 images is 20 cm range at 2.5 mm thick
Low Dose CT Lung Biopsy Scan 2 Scan 1 Scan 3
Scan 5 Scan 4
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
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