Unit 10 - Renal Transplant

What is the role of ultrasound when scanning a renal transplant?

Monitor for rejection & other complications after the transplant

What are other complications after a renal transplant?

• Acute tubular necrosis (ATN)

• Obstructive nephropathy

• Extraperitoneal fluid collections

• Hemorrhage

• Infarction

• Recurrent glomerulonephritis

• Graft rupture

• Renal emphysema

Most renal transplant patients have had ______ term renal failure without ___________ nephropathy.

Long, obstructive

What are the pre-transplant risk factors that are considered?

• Age

• Primary diagnosis

• Medical complications

• Transplant source

What patients have the lowest risk when considering a renal transplant?

• 16-45 year olds

• Primary renal disease

What is the major problem with renal transplants?

Graft rejection

With a living kidney donor, what is the average survival rate?

75%, 5-years

With a cadaver kidney donor, what is the average survival rate?

60%, 5-years

What is the surgical procedure of a renal transplant?

• Removal of donor’s kidney (Lt.), vessels, ureter

• Rotated & placed in recipient’s Rt iliac fossa

• Anastomosed to iliac vessels

• Ureter inserted in bladder

With a renal transplant, when is the baseline US exam performed?

Within 48 hours after the transplant

What does a sonographer look for in the baseline US exam?

• Renal size

• Calyceal pattern / Hydronephrosis

• Extrarenal or Perirenal fluid collections

• Blood Perfusion exam / Doppler PW & Color

• Rejection (high RI’s)

• Bladder exam

What should be done with Longitudinal & Transverse scans of the kidneys?

Made parallel & perpendicular to long axis of the kidney

What RI’s are needed to be evaluated in the Doppler portion of the exam?

• Main Renal Artery (>correct)

  • Anastomosis, mid, distal

• Iliac Artery (>correct)

• Main Renal Vein (>correct)

• Indirect Doppler

  • Color flow to demonstrate perfusion

A _______ is needed to diagnose rejection, US guidance is used.

Biopsy

What is this image showing?

Biopsy of the left kidney

What are the types of rejection?

1. Hyperacute

2. Acute

3. Immunologic

4. Chronic

When does a Hyperacute rejection occur?

Within hours of the transplant

When does an Acute rejection occur?

Within days to months after transplant

What are the causes of an Immunologic rejection?

• Performed antibodies

• Immune complexes

• Cell-mediated responses

When does a Chronic rejection occur?

Months after transplant with gradual onset

US is very important in the diagnosis of rejection, what should be observed?

• Size

• Shape

• Appearance of pyramids, cortex, & parenchyma

• Fluid collections

• RI’s

Rejection Pattern #1:

Enlargement & decreased echogenicity of pyramids

• Not uniform

Rejection Pattern #2:

Hyperechoic cortex

Rejection Pattern #3:

Localized area of renal parenchyma with anechoic area in polar areas

Rejection Pattern #4:

Distortion of renal outline

• Localized- involving both cortex & pyramids

• Sinus may appear compressed & displaced

Rejection Pattern #5:

Patchy sonolucent areas - both cortex & medulla

• Follow-up becomes extensive affecting a large portion of the renal parechyma

What is this image showing?

Chronic renal transplant rejection

What is this image showing?

Distortion of the renal outline

• Localized areas of swelling involving both the cortex & pyramids

• Renal sinus echoes may appear compressed and displaced

What is this image showing?

• Hyperechoic cortex appears as swollen sonolucent pyramids

  • W/ background of ^ echogenicity of the outer and interpyramidal cortex

• Mild dilation of the renal pelvis and ureter

RP ~ Long-Standing Rejection: A normal-size transplanted kidney has...

Very little differentiation between parenchymal & renal sinus echoes

RP ~ Long-Standing Rejection: A small transplanted kidney has…

• Irregular margins

• Parenchymal echo pattern

RP ~ Physiology: A hypoechoic appearance, can be a sign of what diseases?

• Edema

• Congestion

• Hemorrhage of interstitium

RP ~ Physiology: A hyperechoic appearance, can be a sign of what diseases?

• Ischemia

• Cellular infiltration

• Infarction & necrosis

RP ~ Physiology: A irregular parenchymal echo pattern appearance, can be a sign of what diseases?

• Parenchymal atrophy

• Fibrosis

• Shrinkage

• From long-standing rejection

When does a graft rupture usually occur?

In the first 2 weeks of post-op

What are the symptoms of a graft rupture?

• Abrupt onset of pain

• Swelling

• Oliguria

• Shock

What is the sonographic appearance of graft rupture?

• Gross distortion of graft contour

• Perinephric or paranephric hematoma

RI Relevance Post Op: Immediately

• Patency of renal vein

• RAS

• Extrarenal compression

  • Adult allograft in a child

• ATN

  • Biopsy to confirm

RI Relevance Post Op: Within a Few Days

• Obstructive uropathy

• Hydronephrosis

• Pyelonephritis

• Pyuria

• Extrarenal compression

• Extrarenal fluid collections

RI Relevance Post Op: Second Week

• Rejection

  • (Especially with elevated Creatinine levels)

  • Biopsy to confirm

What are these images showing?

Normal Flow Patterns Post-Transplant

What are the different types of flow patterns considered abnormal?

1. Tardus parvus @ inferior segmental (RAS)

2. Elevated RI (ATN)

3. Elevated RA – Acute Rejection by biopsy

What is this image showing?

Abnormal Flow Patterns (Tardus parvus)

What is this image showing?

Abnormal Flow Patterns (increased RI)

What is this image showing?

Abnormal Flow Patterns (increased velocity)

With an increased RI Relevance, what are the significant consisderations?

• Postoperative time

• Patient history

• Donor history

• Clinical findings

What does AVM stand for?

Arteriovenous malformation

What are the different types of AVM that can occur after a biopsy?

• Pseudoaneurysms

  • Show “to-fro” flow

• Arteriovenous fistula

  • Show turbulent flow in area

An increase in Heart Rate =

A decrease in RI

Contrast agents are not yet approved by the ____ for the kidney.

FDA

What does research show about using contrast agents in the kidneys?

• Encouraging results

  • Increase in visualization of RAs

  • Decrease scanning time

What does CEUS stand for?

Continuing Education Units