Renal ultrasound: Difference between revisions
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== | ==Background== | ||
[[File:Urinary system.png|thumb|(1) Human urinary system: (2) kidney; (3) renal pelvis; (4) ureter; (5) urinary bladder (6) urethra. Additional structures: (7) adrenal gland; (8) renal artery and vein; (9) inferior vena cava; (10) abdominal aorta; (11) common iliac artery and vein; (12) liver; (13) large intestine; (14) pelvis.]] | |||
* | *Bedside renal ultrasound has accepted use in the diagnosis of [[nephrolithiasis]] | ||
* | *In comparison of diagnosis by CT vs. U/S (by EP) vs. U/S (by radiologist):<ref>Smith-Bindman R, Aubin C, Bailitz J, et al. Ultrasonography versus computed tomography for suspected nephrolithiasis. NEJM. 2014; 371(12):1100–1110.</ref> | ||
* | **No difference in rate of missed high-risk diagnoses that resulted in complications (pyelo/sepsis/diverticular abscess) | ||
**No difference in rate of serious adverse events, pain scores, return emergency department visits, or hospitalizations | |||
==Indications== | |||
*[[Flank pain]] | |||
*Suspected [[nephrolithiasis]] | |||
*Hematuria | |||
*Dysuria | |||
*Anuria | |||
==Technique== | ==Technique== | ||
# | #Select probe | ||
#Right kidney | #*Curvilinear/large convex probe (phased array probe may substitute) | ||
# | #Location | ||
# | #*Right kidney | ||
#Left kidney | #**Patient supine | ||
# | #**Probe in the right lower intercostal space in the midaxillary line | ||
# | #*Left kidney | ||
# | #**Patient supine or right lateral decubitus | ||
#**Probe in the lower intercostal space on the posterior axillary line | |||
#**More cephalad and posterior than when visualizing the right kidney | |||
#Scan entire kidney (through liver) | #Scan entire kidney (through liver) | ||
# | #*Longitudinal (long axis) and transverse (short axis) views | ||
#Scan the [[ | #Scan the [[Bladder ultrasound|bladder]] | ||
==Findings== | ==Findings== | ||
[[File:Hydro.png|200px]] | |||
*Hydronephrosis | *Hydronephrosis | ||
**Mild: Distention of collecting system | **Mild: Distention of collecting system | ||
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**Severe: Dilated renal calyces and cortical thinning<ref>Cosby, K. (2006) Practical Guide to Emergency Ultrasound. Philadelphia, PA: Lippincott Williams & Wilkins pp. 237, 245-248</ref> | **Severe: Dilated renal calyces and cortical thinning<ref>Cosby, K. (2006) Practical Guide to Emergency Ultrasound. Philadelphia, PA: Lippincott Williams & Wilkins pp. 237, 245-248</ref> | ||
***“Bear claw” appearance | ***“Bear claw” appearance | ||
*** | ***Represents severe obstructive uropathy | ||
==Images== | |||
===Normal=== | |||
<gallery> | |||
File:No hydro still.jpg|No hydronephrosis | |||
</gallery> | |||
===Abnormal=== | |||
<gallery> | |||
File:Mild hydro.png|Mild hydro | |||
File:Moderate hydro.jpg|Moderate hydro | |||
File:Severe hydro still image.jpg|Severe hydro | |||
File:Ultrasonography of renal stone located at the pyeloureteric junction.jpg|Ureteral stone located at the pyeloureteric junction with accompanying hydronephrosis | |||
</gallery> | |||
==Pearls and Pitfalls== | |||
*Patients that are overhydrated, pregnant, or with a full-bladder may have mild hydronephrosis bilaterally without obstruction | |||
*Underhydrated patients may not have hydronephrosis on initial renal scanning, despite obstruction | |||
*Renal cysts can sometimes be mistaken for hydronephrosis | |||
**Cysts are typically single, circular, and arise in the periphery of the kidney | |||
**They can be multiple as in polycystic kidney disease | |||
===Renal Cyst Classification=== | |||
*Bosniak I :Benign simple cyst with thin wall without septa, calcifications, or solid components. | |||
*Bosniak II: Benign cyst with a few thin septa, which may contain fine calcifications or a small segment of mildly thickened calcification. Hyperdense cysts must be exophytic with at least 75% of its wall outside the kidney to allow for appropriate assessment of margins, otherwise they are categorized as IIF. | |||
**Bosniak IIF: Includes renal cysts with multiple thin septa, a septum thicker than hairline, slightly thick wall, or with calcification, which may be thick. It also includes intrarenal cysts larger than 3 centimetres (1.2 inches). Category IIF cysts have a 5-10% risk of being kidney cancer, and therefore follow-up is recommended every 6 months. | |||
*Bosniak III: Indeterminate cystic masses with thickened irregular septa with enhancement. 50 % of these lesions are ultimately found to be malignant. | |||
*Bosniak IV: Malignant cystic masses with all the characteristics of category III lesions but also with enhancing soft tissue components on CT independent of but adjacent to the septa. 100 %of these lesions are malignant. | |||
==Documentation== | |||
===Normal Exam=== | |||
A bedside ultrasound was conducted to assess for hydronephrosis with clinical indication of left/right flank pain. The left kidney, right kidney, and bladder were identified in the transverse and sagittal plane. There was no hydronephrosis identified. | |||
===Abnormal Exam=== | |||
A bedside ultrasound was conducted to assess for hydronephrosis with clinical indication of left/right flank pain. The left kidney, right kidney, and bladder were identified in the transverse and sagittal plane. There was mild/moderate/severe hydronephrosis identified on the left/right. | |||
==Clips== | |||
===Normal=== | |||
<gallery> | |||
File:No hydro.gif | |||
</gallery> | |||
===Abnormal=== | |||
<gallery> | |||
File:Mild hydro.gif|Mild hydro | |||
File:Moderate hydro clip.gif|Moderate hydro | |||
File:Severe hydro.gif|Severe hydro | |||
</gallery> | |||
===Pitfall=== | |||
<gallery> | |||
File:Nonobstructing stone.gif|Nonobstructing stone | |||
File:Color flow kidney no hydro.gif|Using color flow to determine vasculature vs hydro | |||
</gallery> | |||
==External Links== | |||
*[http://www.sonoguide.com/renal.html Sonoguide: Renal Ultrasound] | |||
==See Also== | ==See Also== | ||
*[[ | *[[Nephrolithiasis]] | ||
*[[ | *[[Flank pain]] | ||
*[[ | *[[Ultrasound (main)]] | ||
==References== | ==References== | ||
<references/> | <references/> | ||
[[Category:Ultrasound]] | [[Category:Ultrasound]] | ||
[[Category:Radiology]] | |||
[[Category:Renal]] | |||
Latest revision as of 16:33, 16 June 2021
Background
- Bedside renal ultrasound has accepted use in the diagnosis of nephrolithiasis
- In comparison of diagnosis by CT vs. U/S (by EP) vs. U/S (by radiologist):[1]
- No difference in rate of missed high-risk diagnoses that resulted in complications (pyelo/sepsis/diverticular abscess)
- No difference in rate of serious adverse events, pain scores, return emergency department visits, or hospitalizations
Indications
- Flank pain
- Suspected nephrolithiasis
- Hematuria
- Dysuria
- Anuria
Technique
- Select probe
- Curvilinear/large convex probe (phased array probe may substitute)
- Location
- Right kidney
- Patient supine
- Probe in the right lower intercostal space in the midaxillary line
- Left kidney
- Patient supine or right lateral decubitus
- Probe in the lower intercostal space on the posterior axillary line
- More cephalad and posterior than when visualizing the right kidney
- Right kidney
- Scan entire kidney (through liver)
- Longitudinal (long axis) and transverse (short axis) views
- Scan the bladder
Findings
- Hydronephrosis
- Mild: Distention of collecting system
- Moderate: Dilation of collecting system, rounding of calyces
- Severe: Dilated renal calyces and cortical thinning[2]
- “Bear claw” appearance
- Represents severe obstructive uropathy
Images
Normal
No hydronephrosis
Abnormal
Mild hydro
Moderate hydro
Severe hydro
Ureteral stone located at the pyeloureteric junction with accompanying hydronephrosis
Pearls and Pitfalls
- Patients that are overhydrated, pregnant, or with a full-bladder may have mild hydronephrosis bilaterally without obstruction
- Underhydrated patients may not have hydronephrosis on initial renal scanning, despite obstruction
- Renal cysts can sometimes be mistaken for hydronephrosis
- Cysts are typically single, circular, and arise in the periphery of the kidney
- They can be multiple as in polycystic kidney disease
Renal Cyst Classification
- Bosniak I :Benign simple cyst with thin wall without septa, calcifications, or solid components.
- Bosniak II: Benign cyst with a few thin septa, which may contain fine calcifications or a small segment of mildly thickened calcification. Hyperdense cysts must be exophytic with at least 75% of its wall outside the kidney to allow for appropriate assessment of margins, otherwise they are categorized as IIF.
- Bosniak IIF: Includes renal cysts with multiple thin septa, a septum thicker than hairline, slightly thick wall, or with calcification, which may be thick. It also includes intrarenal cysts larger than 3 centimetres (1.2 inches). Category IIF cysts have a 5-10% risk of being kidney cancer, and therefore follow-up is recommended every 6 months.
- Bosniak III: Indeterminate cystic masses with thickened irregular septa with enhancement. 50 % of these lesions are ultimately found to be malignant.
- Bosniak IV: Malignant cystic masses with all the characteristics of category III lesions but also with enhancing soft tissue components on CT independent of but adjacent to the septa. 100 %of these lesions are malignant.
Documentation
Normal Exam
A bedside ultrasound was conducted to assess for hydronephrosis with clinical indication of left/right flank pain. The left kidney, right kidney, and bladder were identified in the transverse and sagittal plane. There was no hydronephrosis identified.
Abnormal Exam
A bedside ultrasound was conducted to assess for hydronephrosis with clinical indication of left/right flank pain. The left kidney, right kidney, and bladder were identified in the transverse and sagittal plane. There was mild/moderate/severe hydronephrosis identified on the left/right.
Clips
Normal
Abnormal
Mild hydro
Moderate hydro
Severe hydro
Pitfall
Nonobstructing stone
Using color flow to determine vasculature vs hydro
