Direct MR Arthrography of Hip joint in Children for Acetabular Labrum- Techniques, Findings and Pitfalls
*Zahir U Sarwar, MBBS, CAQ, Pediatric Radiology, *Nemours Clinic and Wolfson Children’s Hospital, Jacksonville, FL, zsawar@nemors.org; **Seth J Crapp, MD, *Kevin Neal, MD, *Inbal Cohen MD, Chief Pediatric Radiology- **University of Florida College of Medicine 
Shands Hospital-Jacksonville, FL Presented at the Society for Pediatric Radiology Conference, Scottsdale, Arizona 2008

1. needed.
Direct MR Arthrography of Hip joint in Children for Acetabular Labrum-
Techniques, Findings and Pitfalls
*Zahir U Sarwar, MBBS, CAQ, Pediatric Radiology, *Nemours Clinic and Wolfson Children’s Hospital, Jacksonville, FL, zsawar@nemors.org;
**Seth J Crapp, MD, *Kevin Neal, MD, *Inbal Cohen MD, Chief Pediatric Radiology- **University of Florida College of Medicine
Shands Hospital-Jacksonville, FL
Introduction Pitfalls
Table 1: Patient with MR Arthrogram and arthroscopy. Table 2: Hips with MR arthrography and without arthroscopy
FA Case Labral tear Labral Absent Irregular Labral sulcus Labral
Cas Procedure Labral Labral Absent Irregular High Labral Labral Ag
I hypertrophy labrum labrum
S
FV e e
T RF Ip P total /recess High
GP tear Hypertroph labrum labrum signal sulcus/ DJ
JC Side y 29 AS=11 0 0 AS=4 AS=0 AS=12
1/rt MRI N N N N AS N AS 18
Magnetic resonance (MR) hip arthrography is a minimally invasive well established diagnostic tool for IL F Ip
JC Art N N N N AS Sublabral sulcus: Sublabral sulci can be found in all anatomic location and some could be retrospectively visualized in
imaging the labrum [5,12,18]. Distension of the capsule with intraarticular gadolinium enhances the MRI
F
Gmx
2/lt MRI SL AS/PS/SL N N AS/
labru N
recess N 15 Signal/DJ MRI[13,14]. Dinauer et al. first described posteroinferior sublabral groove or sulcus as a relatively common finding[13].
PS=0 N=25 PS=5 PS=0
appearance of the labrum and allows improved detection of labral abnormalities [4]. However , experience in Art N P N N
PS/SL
m
N PS
Posteroinferior tear is rare. However, it is more common in Japan [13,16] In their study of 58 patients, 22.4% had
Gme
children is limited. The purpose of this article is to describe the technique of Fluoroscopy guided Hip 3/rt MRI AS/SL AS/PS/SL N N AS/ N AS/PS/ 18 posteroinferior sulcus. (fig 10). Saddik et al described anterosuperior, anteroinferior, posterosuperior and posteroinferior sulcus
Arthrography. To understand the MR anatomy of the acetabular labrum in children and normal variants
Gmx SL SL SL=4 SL=4 SL=3 [14, 8]]. We could not find any description of superolateral sublabral sulcus (fig 10). Two of our patient was had negative
AS AS/SL P N N AS/SL
mimicking labral tear.
IL arthroscopy for suspected superolateral tear and possibly had sulcus (fig 15).
4/rt MRI AS/SL N N AS/SL AS/ N AS/SL 18 AS= Anterosuperior, PS= posterosuperior, SL=Superolateral, N=Not
SL found, P= Present
AS+SL=1 AS+PS=1 AS+L=1
Unossified triradiate cartilage: In young children unossified triradiate cartilage of intermediate signal intensity in T1 fat
Art AS/SL N N AS/SL AS/SL
suppressed image Labrum overlying the triradiate cartilage (fig 13) should not be interpreted as degeneration. Intrasubstance high
Figure 1. Needle tract: Axial (left) and sagittal (right) T1 fat
5/rt MRI AS N N N AS SL N 16 signal is difficult to characterize.
Art AS N N N N
Materials & Methods
suppressed images showing needle tract. Rectus femoris m. (RF), 6/lt MRI AS AS/PS/SL N N AS/ N AS/SL 20
iliopsoas m. (Ip), iliofemoral ligament (IL), tensor fascia lata m. (T), Art AS P N N SL AS/SL Posterior labrum high signal: Intrasubstance high signal when present in the posterosuperior labrum is a challenge.
sartorius m.(S), femoral artery (FA), femoral vein (FV), pectineus m.
7/rt MRI
Art
AS
AS
N
N
N
N
N
N
N PS N
N
17
Posterosuperior labral tear is rare but has been described in young patients and in Japanese.
(P), femoral head (F), joint capsule (JC), growth plate (GP), iliacus m. 8/rt MR AS N N N AS N AS 12
(I), gluteus medius (GMe), gluteus maximus (Gmx)
Art AS N N N AS Posterior cleft formed at the junction of the transverse ligament and labrum may give false impression of labral tear (fig 14) [13].
9/rt MR AS N N N AS N AS 18
Art AS N N N N
We retrospectively evaluated thirty-eight MR hip athrography studies performed on thirty-eight patients Art=Arthroscopy, DJ=Degeneration, AS= Anterosuperior, PS=posterosuperior,
in our institution. Six patient had bilateral hip arthrography performed in a single setting. One patient had SL=Superolateral, N=Not found, P= Present,
two arthrographies performed on the same hip for recurrent symptoms. Age of the patients ranged from
twelve to twenty . Nine patients, so far have underwent arthroscopic surgery. All imaging was performed
within two hours of arthrogram in a GE 1.5 Tesla magnet using 8-chanell cardiac coil. GMe Figure 5 . Anterosuperior full thickness labral tear, a.
SL
GMi
Pv
TL Axial T1 fat sat image showing full thickness
anterosuperior labral tear with high signal (white arrow).
LT
FH Paralabral cyst (yellow arrow) b. Sagittal image showing
Techniques
ZO full thickness tear.
GT
IL
IL
Pe
ItL
Figure 13. Triradiate cartilage: Unossified triradiate
V cartilage has bright signal (red arrow) on these
Figure 10. Posterior sublabral sulcus: Axial T1 fat sat image shows coronal (left) and sagittal (right) T1 fat sat images
Figure 4. Anterosuperior (AS) and superolateral (SL) partial homogenous and triangular shaped posterosuperior labrum with a
Technique of Flouroscopy guided arthrogram: sublabral sulcus( white arrow).
The patient is positioned supine. The hip is maximally internally rotated without patient discomfort. After local thickness tear: Axial (left) T1 fat-sat image showing contrast
anesthesia a 22 gauge spinal needle is vertically introduced in the femoral neck till it touches the bone. The Figure 2. Hip anatomy: Superior labrum (SL), inferior labrum (IL), extendinding in the AS labrum ( white arrow) and preserved Figure 14 (left). A and b.
needle is aimed at the center of the femoral neck. Once the needle is in contact with the bone, the stylet is transrverse ligament (TL), ligamentum teres (LT), perilabral recess (red perilabral recess (yellow arrow) in keeping with AS partial Bilateral superolateral
withdrawn and half to one ml of buffered lidocaine is injected to anesthetize the periosteum. Free flow of arrow), zona orbicularis (ZO), periosteum (Pe), pulvinar (Pv), femoral thickness tear (white arrow). sublabral triangular shaped
lidocaine indicates intra articular location of the needle tip. Ten to fifteen ml of a solution of 0.75 to 1% solution head (FH), gluteus minimus (GMi), gluteus medius (GMe), recess (white arrow) with
of gadolinium(0.15/0.2 ml of magnevist+ 5ml Optiray 300+ 5 ml .25% sensorcaine+ 10 ml normal saline) is intertrochanteric line (ItL), greater trochanter (GT), vastas lateralis (V) Figure 6 (left). Labral degeneration: Figure 7a, Anterosuperior full-thicknes tear with labral homogenously low signal
injected in the joint. Axial T1 fat suppressed image
hypertrophy(white arrow) in a patient with history of AVN. b. triangular shaped
showing anterosuperior labral high
Axial image showing a paralabral cyst (white arrow). Note labrum(yellow arrow) and
signal due to intrasubstance
MRI sequence: obliteration of anterior perilabral recess(green arrow) Preserved intact perilabral recess(red
degneration without tear.
All patients were imaged within two hours of injection for maximum contrast effect [20]. MRI was performed in Intrasubstance mild posterior high posterior perilabral recess(small arrow). Posterior labral arrow)
a 1.5 Tesla GE magnet using 8 Channel Cardiac coil. Our standard protocol includes axial, sagittal and coronal signal possibly secondary to hyperthrophy ( yellow arrow)
T1 fat suppressed imaging at 3mm slice thickness with 1 mm gap, coronal inversion recovery sequence at 3mm vascularity. The posterior labrum was Figure 15. Arthrscopic image
with 0 to1 gap, axial MPGR at 3to 5 mm slice thickness with 1 to 2 mm gap and coronal 3DSPGR 1mm slice normal on arthroscopy. demonstrating labral tear
thickness ( flip angle of 40). Field of view 18 to 22 cm and matrix size was 256X192-256. TR and TE were
optimized according to number of slices at the discretion of the technologist to reduce scanning time. Axial,
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fat sat image showing anterosuperior
labral high signal intensity (white
Figure 3. Right: Transeverse ligament (red arrow), and Left:
Results
arrow). Femoral head cortical defect
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