Stone protocol CT: Why, How and Pitfalls
-
Upload
rathachai-kaewlai -
Category
Health & Medicine
-
view
1.688 -
download
1
Transcript of Stone protocol CT: Why, How and Pitfalls
![Page 1: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/1.jpg)
Hello…. CT Stone Protocol
Why, How and Pitfalls
Rathachai Kaewlai, MD
Division of Emergency Radiology, Department of Radiology
Ramathibodi Hospital, Bangkok, Thailand
For RCRT-RST Annual Scientific Meeting, 24 Mar 2016
![Page 2: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/2.jpg)
Why – How – Pitfalls
![Page 3: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/3.jpg)
Why NCCT for KUB Stone?
![Page 4: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/4.jpg)
Virtually All KUB Stones Are Radiopaque on CT Composition Frequency
(%) Radiopacity Radiograph
Shade of White on CT
Calcium phosphate 10 4
Calcium phosphate/oxalate
40 3-4
Calcium oxalate 30 3
Struvite 10 2-3
Cystine 1 1
Uric acid 10 0
Genitourinary Imaging: the Requisite
![Page 5: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/5.jpg)
Stone Types Based On CT Characteristics
![Page 6: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/6.jpg)
Detection of Stones
X-ray IVU Ultrasound NCCT
Sensitivity (%) 44-77 52-87 19-93 94-100
Specificity (%) 80-87 94-100 84-100 92-100
![Page 7: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/7.jpg)
ACR Appropriateness Criteria (2015)
![Page 8: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/8.jpg)
ACR Appropriateness Criteria (2015)
![Page 9: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/9.jpg)
ACR Appropriateness Criteria (2015)
![Page 10: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/10.jpg)
Diagnostic Strategies
![Page 11: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/11.jpg)
Factor Definition Level Points
Sex Female Male
0 2
Timing Duration of pain from onset to presentation, h
>24 6-24 <6
0 1 3
Origin Race Black Nonblack
0 3
Nausea Presence of nausea and vomiting
None Nausea only Vomiting
0 1 2
Erythrocyte Hematuria on urine dip Absent Present
0 3
Total 0-13
STONE score for uncomplicated ureteral stone in ED
Moore CL, et al. BMJ 2014;348:g2191
![Page 12: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/12.jpg)
Points Probability of
symptomatic stone on CT %
Recent validation
(n=264)
0 to 5 Low 10% 10%
6 to 9 Moderate 10-90% (~50%)
60%
10 to 13 High >90% 89%
STONE score for uncomplicated ureteral stone in ED
Moore CL, et al. BMJ 2014;348:g2191 Moore CL, et al. Radiology 2016 March
![Page 13: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/13.jpg)
STONE score Sensitivity Specificity
Low probability (n=144) without ultrasound with ultrasound
3 64
67 87
Moderate probability (n=411) without ultrasound with ultrasound
41 60
42 71
High probability (n=280) without ultrasound with ultrasound
55 69
91 60
Daniels B, et al. Ann Emerg Med 2016 March
STONE PLUS for uncomplicated ureteral stone in ED
![Page 14: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/14.jpg)
Daniels B, et al. Ann Emerg Med 2016 March
![Page 15: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/15.jpg)
Ramathibodi Protocol (WIP) < 80 kg >/= 80 kg
kVp 100 120
mA 70-250 70-350
Rotation time (s) 0.6 0.6
SureExposure 3D 20 20
PF/HP 0.828/53 0.828/53
Slice thickness/interval (mm) 2.0/1.5 2.0/1.5
![Page 16: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/16.jpg)
Stone CT Radiation Dose
![Page 17: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/17.jpg)
Stone CT Radiation Dose: How Low Can We Go?
![Page 18: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/18.jpg)
Moore CL, et al. Ann Emerg Med 2015;65:189
N=201 Prospective, head-to-head comparison standard v reduced-dose CT
Two groups: BMI <30 v. BMI >30
![Page 19: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/19.jpg)
2.2 mSv
Reduced-dose CT
![Page 20: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/20.jpg)
Initial CT
F/U CT (known stone) Can accept more noise to reduce dose
8.3 mSv
3.7 mSv
![Page 21: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/21.jpg)
How About Giving IV Contrast?
![Page 22: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/22.jpg)
Forniceal rupture with urinoma due to obstructing Lt UVJ stone
UVJ stone
Delayed nephrogram
Perinephric fluid
Urine extravasation confirmed at delayed scan although this phase is not necessary
![Page 23: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/23.jpg)
McLaughlin PD, et al. Insights Imaging 2014;5:217
5.1 mSv (ASiR)
5.1 mSv (FBP)
0.56 mSv (FBP)
0.56 mSv (40% ASiR)
0.56 mSv (70% ASiR)
0.56 mSv (90% ASiR)
CT Doses Even Lower than Abdominal Radiograph
N=33 Comparing routine and sub-mSv CT (with iterative recon)
Calculi >3 mm: Sensitivity 87%, specificity 100%
1 missed appendicitis 1 missed dermoid
Advanced scanner can reduce dose further with
iterative reconstruction
![Page 24: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/24.jpg)
High-density calcium stone in renal pelvis with obstruction
Advanced scanner can predict which stone is uric acid (medical) or non-uric acid
![Page 25: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/25.jpg)
How We Interpret CT Stone Protocol
![Page 26: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/26.jpg)
Soft tissue rim sign = ureteral stone
![Page 27: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/27.jpg)
Stone Size and Appearance
![Page 28: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/28.jpg)
Perinephric/periureteric Changes
![Page 29: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/29.jpg)
Risks for Stone Formation Identifiable on Imaging
![Page 30: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/30.jpg)
Typical Cases
hydronephrosis
stone
![Page 31: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/31.jpg)
Distal ureteric stone with obstruction
Typical Cases
Hydronephrosis & minimal perinephric fat stranding
stone
![Page 32: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/32.jpg)
Unilateral Perinephric Fat Stranding w/o Stone - DDx
![Page 33: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/33.jpg)
Mimickers on CT of:
![Page 34: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/34.jpg)
Moore CL, et al. Acad Emerg Med 2013;20:470
N=5383 Descriptive study No comparison Two EDs
Alternative Diagnosis
![Page 35: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/35.jpg)
Incidental Findings
Samim MM, et al. JACR 2015;12:63
![Page 36: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/36.jpg)
Samim MM, et al. JACR 2015;12:63
N=5383 Descriptive study, no comparison Two emergency departments
![Page 37: Stone protocol CT: Why, How and Pitfalls](https://reader031.fdocuments.us/reader031/viewer/2022022014/58f9b1a2760da3da068bc2ac/html5/thumbnails/37.jpg)
Take Home Messages