Renal ultrasound: Difference between revisions
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==Background== | ==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]] | *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> | *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 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 | **No difference in rate of serious adverse events, pain scores, return emergency department visits, or hospitalizations | ||
==Indications== | ==Indications== | ||
*[[Flank pain]] | *[[Flank pain]] | ||
*Suspected [[nephrolithiasis]] | *Suspected [[nephrolithiasis]] | ||
*Hematuria | |||
*Dysuria | |||
*Anuria | |||
==Technique== | ==Technique== | ||
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File:Moderate hydro.jpg|Moderate hydro | File:Moderate hydro.jpg|Moderate hydro | ||
File:Severe hydro still image.jpg|Severe 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> | </gallery> | ||
==Pearls and Pitfalls== | ==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 | *Renal cysts can sometimes be mistaken for hydronephrosis | ||
**Cysts are typically single, circular, and arise in the periphery of the kidney | **Cysts are typically single, circular, and arise in the periphery of the kidney | ||
**They can be multiple as in polycystic kidney disease | **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== | ==Documentation== | ||
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
