Diagnostic Ultrasound - Abdomen and Pelvis

Renal Junction Line
TERMINOLOGY
Synonyms
• Junctional parenchymal defect
• Interrenuncular septum
• Oddono sulcus
○ Named after Oddono, who described this in 1899
Definitions
• Defect or line representing incomplete embryologic fusion
of 2 primary renal lobes: Upper and lower poles of kidney
IMAGING
General Features
• Best diagnostic clue
○ Wedge-shaped hyperechoic defect or echogenic line at
upper to middle 1/3 of kidney
○ No associated loss of parenchyma
○ Characteristic location at anterosuperior aspect of kidney
• Location
○ Upper to middle 1/3 in anterior aspect of kidney
○ More commonly seen on right
○ Uncommonly at posteroinferior surface via posterior
approach
• Size
○ Variable size of defect
– Superficial small linear indentation or sulcus
– Deep fissure of varying depth
– Complete cleft with lobar sulcus extending in
continuity into renal sinus
Ultrasonographic Findings
• Grayscale ultrasound
○ Junctional parenchymal defect
– Triangular hyperechoic defect containing fat
– Upper to middle 1/3 of kidney
○ Interrenuncular septum
– Echogenic line at upper to middle 1/3 of kidney
– Connects perirenal space to renal sinus
– Occasionally may indent cortex
CT Findings
• Superficial notch containing fat at anterosuperior aspect of
kidney
• Complete cleft crossing entire thickness of renal
parenchyma into renal sinus
• Overlays column of Bertin
MR Findings
• T1WI
○ Isointense to fat
• T2WI
○ Isointense to fat
• T1WI C+ FS
○ Nonenhancing
○ Calyces may be dilated
• Different location from renal junction line
Fetal Lobulation
• Indentations lie between renal pyramids or calyces
• No cortical loss
Angiomyolipoma
• Discrete, round echogenic mass
• Intraparenchymal in location
PATHOLOGY
General Features
• Layer of connective tissue trapped from fusion of 2
metanephric elements in formation of kidney
Gross Pathologic & Surgical Features
• Deep diagonal groove extending from anterior surface of
upper pole of kidney into hilum
CLINICAL ISSUES
Natural History & Prognosis
• Normal variant
Treatment
• None
DIAGNOSTIC CHECKLIST
Image Interpretation Pearls
• Absence of parenchymal loss useful to differentiate it from
cortical scar
• Characteristic location
• Increased echogenicity on ultrasound
• Fat density on CT
• Fat signal intensity on MR
SELECTED REFERENCES
1. Siegel, Marilyn J. "Urinary Tract." In Pediatric Sonography. 4th ed.
Philadelphia: Lippincott Williams & Wilkins, 2011
2. Hiromura T et al: Lobar dysmorphism of the kidney: reevaluation of
junctional parenchyma using helical CT.Abdom Imaging. Mar-Apr; 24(2):196-
9,1999
3. Currarino G et al: The Oddono's sulcus and its relation to the renal
"junctional parenchymal defect" and the "interrenicular septum". Pediatr
Radiol. 27(1):6-10, 1997
4. Yeh HC et al: Junctional parenchyma: revised definition of hypertrophic
column of Bertin. Radiology. 185(3):725-32, 1992
5. Kenney IJ et al: The renal parenchymal junctional line in children: ultrasonic
frequency and appearances. Br J Radiol. 60(717):865-8, 1987
6. Carter AR et al: The junctional parenchymal defect: a sonographic variant of
renal anatomy. Radiology. 154(2):499-502, 1985
7. Hoffer FA et al: The interrenicular junction: a mimic of renal scarring on
normal pediatric sonograms. AJR Am J Roentgenol. 145(5):1075-8, 1985
Diagnoses: Urinary Tract
DIFFERENTIAL DIAGNOSIS
Scar
• Associated with parenchymal thinning
• Focal indentation directly over calyces
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