Kidney Stone Detection on Ultrasound

Purpose	To detect kidney, ureteral, or bladder stones on US
Tag(s)
Panel	Abdominal
Define-AI ID	20020007
Originator	Luther B. Adair, II
Lead	Luther B. Adair, II
Panel Chair	Arun Krishnaraj
Panel Reviewers	Abdominal Panel
License	Creative Commons 4.0
Status	Public Comment
RadElement Set	RDES158

Clinical Implementation

Value Proposition

Distinguishing between hydronephrosis due to mass effect on the distal ureter in pregnancy versus urolithiasis as a cause is a common reason renal ultrasound is ordered as an alternative to CT. Additionally, renal ultrasound is often ordered in an outpatient setting to ascertain a cause for abnormal renal function, specifically to exclude hydronephrosis. AI meeting this use case would help in detecting, quantitating, comparing, and alerting both nonspecialists and radiologists to these abnormalities. In clinical settings where a radiologist is not readily available, such detection would be of value to non-radiologists such as technologists who would perform an ultrasound for this disease entity. In clinical settings where radiologists are available, such detection could be used to alert the radiologist and prioritize its reporting and notification to the treating physicians.

Narrative(s)

A 35-year old pregnant patient presents to an emergency room with abdominal pain at which time ultrasound is ordered.

A 65-year old patient presents to an outpatient office with abnormal renal function and abdominal pain and ultrasound is ordered.

Workflow Description

The relevant images are obtained from the modality and sent to PACS and the AI engine based on anatomic landmarks. The images are analyzed by the engine. The system then detects the relevant outputs providing associated categorical data or measurements. An alert message is sent back to the engine with information, identification, and graphics highlighting the presence of a renal calculus, ureteral calculus, urinary bladder calculus, or hydronephrosis. Calculus on ultrasound is defined as a hyperechoic focus with posterior shadowing or “twinkle” artifact.

An algorithm evaluates the ultrasound images and assesses whether a renal calculus(s) is present, absent, or undetermined. If present, it then counts the number of calculi in each kidney and measures the largest on each side. It will also assess whether a ureteral calculus is present, absent, or indeterminate. If present, it then measures the calculus. Assesses whether a bladder calculus is present, absent, or undetermined. If present, it then measures the calculus.Assesses whether hydronephrosis is see comment below regarding laterality and quantifying degree of hydronephrosis. For cases where the algorithm returns any degree of hydronephrosis is present, the exam is prioritized in the radiologist’s worklist for urgent interpretation and reporting.

Considerations for Dataset Development

Procedures	{retroperitoneal ultrasound, renal ultrasound, renal ultrasound limited}
View(s)	{transverse, longitudinal}
Age	[0,90]
Sex at Birth	{Male, Female}
Abdominal pain	{left flank pain, right flank pain, abdominal pain}
Other	{hydronephrosis}
Confounding variables	{percutaneous nephrostomy, ureteral catheter, vascular calculus [calcified atherosclerosis in renal arteries], echogenic renal sinus fat, emphysematous pyelonephritis or cystitis, air within the collecting system, Foley catheter}

Technical Specifications

Inputs

DICOM Study

Procedure	Renal ultrasound
Views	Transverse, longitudinal
Data Type	DICOM
Modality	ultrasound
Body Region	Abdomen and pelvis
Anatomic Focus	Kidneys, ureters, urinary bladder

Primary Outputs

Renal Calculus Detection

RadElement ID	RDE1107
Definition	Detection of renal calculus
Data Type	Categorical
Value Set	Absent Present Indeterminate
Units	N/A

Number of Renal Calculus

RadElement ID	RDE1103
Definition	If renal calculus present, note the number of calculi
Data Type	Numeric
Value Set	N/A
Units	N/A

Renal Calculus Kidney Laterality

RadElement ID	RDE1108
Definition	If renal calculus present, note which kidney involved
Data Type	Categorical
Value Set	Left Right Indeterminate
Units	N/A

Renal Calculus Measurement

RadElement ID	RDE1104
Definition	Measurement of renal calculus
Data Type	Numeric
Value Set	N/A
Units	millimeters

Ureteral Calculus Detection

RadElement ID	RDE1109
Definition	Detection of ureteral calculus
Data Type	Categorical
Value Set	Absent Present Indeterminate
Units	N/A

Ureteral Calculus Kidney Laterality

RadElement ID	RDE1110
Definition	If ureteral calculus present, specify which kidney involved
Data Type	Categorical
Value Set	Left Right Indeterminate
Units	N/A

Ureteral Calculus Measurement

RadElement ID	RDE1105
Definition	Measurement of ureteral calculus
Data Type	Numeric
Value Set	N/A
Units	millimeters

Bladder Calculus Detection

RadElement ID	RDE1111
Definition	Detection of bladder calculus
Data Type	Categorical
Value Set	Absent Present Unknown
Units	N/A

Bladder Calculus Measurement

RadElement ID	RDE1106
Definition	Measurement of bladder calculus
Data Type	Numeric
Value Set	N/A
Units	millimeters

Secondary Outputs

Hydronephrosis Detection

RadElement ID	RDE1112
Definition	Detection of hydronephrosis
Data Type	Categorical
Value Set	Absent Present Indeterminate
Units	N/A

Hydronephrosis Kidney Laterality

RadElement ID	RDE1113
Definition	If Hydronephrosis present, note which kidney involved
Data Type	Categorical
Value Set	Left Right Indeterminate
Units	N/A

Future Development Ideas

Possible extension to this use case is to detect nephrolithiasis and hydronephrosis on ultrasound and assess the need for further imaging based on the absence or presence of hydronephrosis.

Related Datasets

No known related public datasets at this time, please alert us if you know of any.