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Radiology Quiz
ARTICLE IN PRESS Current Orthopaedics (2006) 20, 386–392
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journal homepage: www.elsevier.com/locate/cuor
Radiology quiz QUESTIONS Question 1 Figures 1a and b are axial magnetic resonance (MR) images through the L5/S1 disc space in a patient with recurrent sciatica following previous microdiscectomy.
Figure 1
What are the MR sequences? What are the findings? What is the diagnosis?
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ARTICLE IN PRESS Radiology quiz
387
Question 2 Figures 2a–c are axial MR images through the L5/S1 disc space in another patient with recurrent sciatica following previous microdiscectomy. Figure 2d is a sagittal midline image of the same patient.
Figure 2
What are the MR sequences? What are the findings? What is the diagnosis?
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Radiology quiz
Question 3 Figures 3a and b are computed tomographic (CT) images of the pelvis in a patient with ongoing right sacro-iliac joint (SIJ) pain following insertion of a SIJ diastasis screw for pelvic trauma.
Figure 3
What are the findings? What is the diagnosis? What other investigations may be helpful?
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389
Question 4 Figures 4a–c are axial MR images through the wrist at the level of the distal carpal row. Figure 1a is T1 weighted, 1b is a STIR image and 1c is a T1 fat-saturated image with gadolinium enhancement. Figure 4d is a T1 weighted long axis view through the wrist at the level of the trapezoid.
Figure 4
What are the findings? What is the diagnosis? What should happen to the patient next?
ARTICLE IN PRESS 390
Radiology quiz
Question 5 Figure 5a is a radiograph of a patient with wrist pain following a fall. Figures 5b and c are MR arthrogram images of the same wrist (5b a coronal section and 5c an axial section through the level of the proximal carpal row).
Figure 5
What are the radiographic findings? What are the findings on the MR arthrogram?
ARTICLE IN PRESS Radiology quiz
391
Question 6 Figure 6a (sagittal) and 6b (coronal) are MR images of the knee in a young man complaining of pain and swelling following a twisting injury.
Figure 6
What are the findings? What is the diagnosis?
ARTICLE IN PRESS 392
ANSWERS Answer 1. Epidural fibrosis Figure 1a is a T1 weighted MR image (the cerebrospinal fluid is dark). An area of low signal (arrow) can be seen surrounding the right S1 nerve root, replacing the normally high signal epidural fat. Post contrast (Fig. 1b) the area of low signal diffusely enhances consistent with epidural fibrosis. The enhancement of the scar tissue diminishes after about 2 years but some residual enhancement always persists.
Answer 2. Recurrent sequestrated disc Figure 2a is a T1-weighted MR image. A small mass, of intermediate signal intensity, can be seen obliterating the left lateral recess. The mass indents the left side of the thecal sac ( ) and the exiting nerve root is compressed and cannot be identified. Figure 2b is a T2-weighted MR image (the cerebrospinal fluid is bright) showing the thecal indentation clearly. Post contrast (Fig. 2c) the lesion (arrow) enhances peripherally suggesting an intervertebral disc prolapse. Figure 2d is a sagittal T2-weighted MR image confirming the origin of the disc prolapse (arrow) at the L4/ 5 level. The prolapse has lifted the posterior longitudinal ligament away from the back of the vertebral bodies. The ligament (arrowhead) can be seen as a thin dark line tented over the prolapsed disc. The L4/5 and L5/S1 level discs are dehydrated (compare their low T2 signal with the signal from other levels) consistent with degenerative disease. It is important to differentiate recurrent disc from epidural fibrosis as a cause of recurrent sciatic pain following spinal surgery. Fibrosis is managed conservatively but a recurrent disc prolapse may be removed surgically.
Answer 3. Post-operative SIJ infection Figure 3a shows irregular and eroded right SIJ surfaces, widened joint space and bony sclerosis in the surrounding bone of the sacrum and ilium. There has been some significant bony destruction posteriorly in the joint (arrow). The left SIJ is normal (compare the two sides). The infection also involves the metalwork: a dark ‘halo’ is seen surrounding the SIJ screw (Fig. 3b, black arrow). This indicates periprosthetic bone resorption. Whilst such resorption may sometimes be aseptic in origin it must be assumed to be infective in this patient given the other changes in the sacro-iliac joint. An MRI would give information about the extent of bone and soft tissue involvement surrounding the SIJ. Fluoroscopic or CT guided joint aspiration and biopsy would provide tissue for microbiological analysis.
Answer 4. Giant cell tumour of tendon sheath at wrist There is a mass lesion over the dorsum of the wrist (arrowheads) which is heterogenously low signal on all sequences. It shows some peripheral enhancement with gadolinium (Fig. 4c, arrowheads) but no central enhancement (Fig. 4c, long arrow). On the sagittal image, the lesion
Radiology quiz is seen to lie in close approximation to one of the extensor tendons of the back of the wrist (Fig. 4d, long arrow). These features are consistent with a synovial proliferative disorder. These usually arise in the synovium of joints where they are known as pigmented villonodular synovitis (PVNS). The same disease arising in the synovium of a tendon sheath is known as giant cell tumour (as in this example). The lesions consist of histiocytes, hyperplastic synovial elements and giant cells. Haemosiderin deposition occurs and accounts for the low signal seen on all MR sequences. They usually present as a monoarticular arthropathy or a gradually enlarging lump in a young adult. The patient should be referred to a soft tissue sarcoma service for resection. Although the lesion is benign, it has a tendency to recur both at the same site and in neighbouring tendon sheaths.
Answer 5. Scapholunate dissociation (Terry Thomas sign) The distance between the scaphoid and lunate on a plain radiograph should be less than 2 mm. A gap of greater than this (Fig. 5a, arrow; Fig. 5b) indicates scapholunate ligament disruption and scapholunate dissociation. The MR arthrogram images confirm the disruption. Gadolinium is injected at the side of the wrist at the level of the proximal carpal row. The contrast is normally constrained within the radio-ulnar-carpal joint by the intrinsic ligaments of the proximal carpal row. In this patient, the scapholunate ligament disruption has allowed contrast to flow abnormally into the midcarpal joints (Fig. 5b, small arrows). Small fragments of bone can be seen in the gap between scaphoid and lunate as low signal opacities (Fig. 5b, long arrow). The axial image (Fig. 5c) demonstrates the tear directly (long arrow). The residual damaged scapholunate ligament is seen as a ragged piece of tissue (short arrow) surrounded by gadolinium in the widened joint space between the scaphoid (S) and lunate (L). The scapholunate ligament is important for stabilising the wrist joint and damage to it, particularly its dorsal component, can result in dorsal intercalated segment instability (DISI).
Answer 6. Meniscal injury (bucket handle tear) Figure 6a shows a large knee joint effusion, most marked in the suprapatellar pouch (long arrow). The posterior horn of the medial meniscus is small (double arrowhead). It should be at least as big as the anterior horn (arrowhead). Extra meniscal tissue is seen lying anterior to the anterior horn of the medial meniscus (short arrow). Figure 6b shows extra meniscal tissue lying in the intercondylar notch (long arrow) and a tiny residual fragment of meniscal tissue in the medial compartment of the knee (short arrow). Compare with the normal lateral meniscus (arrowhead). These features are consistent with a ‘bucket handle’ tear of the medial meniscus. The ‘bucket handle’ has prolapsed forward and medially and now lies anterior to the anterior horn of the meniscus and in the intercondylar notch. A small remnant of posterior horn is left in the posterior joint. Christopher Hammond, Philip Robinson Department of Radiology, St. James’ University Hospital, Beckett Street, LEEDS LS7 7TF, UK
Available at www.sciencedirect.com
journal homepage: www.elsevier.com/locate/cuor
Radiology quiz QUESTIONS Question 1 Figures 1a and b are axial magnetic resonance (MR) images through the L5/S1 disc space in a patient with recurrent sciatica following previous microdiscectomy.
Figure 1
What are the MR sequences? What are the findings? What is the diagnosis?
0268-0890/$ - see front matter doi:10.1016/j.cuor.2006.02.009
ARTICLE IN PRESS Radiology quiz
387
Question 2 Figures 2a–c are axial MR images through the L5/S1 disc space in another patient with recurrent sciatica following previous microdiscectomy. Figure 2d is a sagittal midline image of the same patient.
Figure 2
What are the MR sequences? What are the findings? What is the diagnosis?
ARTICLE IN PRESS 388
Radiology quiz
Question 3 Figures 3a and b are computed tomographic (CT) images of the pelvis in a patient with ongoing right sacro-iliac joint (SIJ) pain following insertion of a SIJ diastasis screw for pelvic trauma.
Figure 3
What are the findings? What is the diagnosis? What other investigations may be helpful?
ARTICLE IN PRESS Radiology quiz
389
Question 4 Figures 4a–c are axial MR images through the wrist at the level of the distal carpal row. Figure 1a is T1 weighted, 1b is a STIR image and 1c is a T1 fat-saturated image with gadolinium enhancement. Figure 4d is a T1 weighted long axis view through the wrist at the level of the trapezoid.
Figure 4
What are the findings? What is the diagnosis? What should happen to the patient next?
ARTICLE IN PRESS 390
Radiology quiz
Question 5 Figure 5a is a radiograph of a patient with wrist pain following a fall. Figures 5b and c are MR arthrogram images of the same wrist (5b a coronal section and 5c an axial section through the level of the proximal carpal row).
Figure 5
What are the radiographic findings? What are the findings on the MR arthrogram?
ARTICLE IN PRESS Radiology quiz
391
Question 6 Figure 6a (sagittal) and 6b (coronal) are MR images of the knee in a young man complaining of pain and swelling following a twisting injury.
Figure 6
What are the findings? What is the diagnosis?
ARTICLE IN PRESS 392
ANSWERS Answer 1. Epidural fibrosis Figure 1a is a T1 weighted MR image (the cerebrospinal fluid is dark). An area of low signal (arrow) can be seen surrounding the right S1 nerve root, replacing the normally high signal epidural fat. Post contrast (Fig. 1b) the area of low signal diffusely enhances consistent with epidural fibrosis. The enhancement of the scar tissue diminishes after about 2 years but some residual enhancement always persists.
Answer 2. Recurrent sequestrated disc Figure 2a is a T1-weighted MR image. A small mass, of intermediate signal intensity, can be seen obliterating the left lateral recess. The mass indents the left side of the thecal sac ( ) and the exiting nerve root is compressed and cannot be identified. Figure 2b is a T2-weighted MR image (the cerebrospinal fluid is bright) showing the thecal indentation clearly. Post contrast (Fig. 2c) the lesion (arrow) enhances peripherally suggesting an intervertebral disc prolapse. Figure 2d is a sagittal T2-weighted MR image confirming the origin of the disc prolapse (arrow) at the L4/ 5 level. The prolapse has lifted the posterior longitudinal ligament away from the back of the vertebral bodies. The ligament (arrowhead) can be seen as a thin dark line tented over the prolapsed disc. The L4/5 and L5/S1 level discs are dehydrated (compare their low T2 signal with the signal from other levels) consistent with degenerative disease. It is important to differentiate recurrent disc from epidural fibrosis as a cause of recurrent sciatic pain following spinal surgery. Fibrosis is managed conservatively but a recurrent disc prolapse may be removed surgically.
Answer 3. Post-operative SIJ infection Figure 3a shows irregular and eroded right SIJ surfaces, widened joint space and bony sclerosis in the surrounding bone of the sacrum and ilium. There has been some significant bony destruction posteriorly in the joint (arrow). The left SIJ is normal (compare the two sides). The infection also involves the metalwork: a dark ‘halo’ is seen surrounding the SIJ screw (Fig. 3b, black arrow). This indicates periprosthetic bone resorption. Whilst such resorption may sometimes be aseptic in origin it must be assumed to be infective in this patient given the other changes in the sacro-iliac joint. An MRI would give information about the extent of bone and soft tissue involvement surrounding the SIJ. Fluoroscopic or CT guided joint aspiration and biopsy would provide tissue for microbiological analysis.
Answer 4. Giant cell tumour of tendon sheath at wrist There is a mass lesion over the dorsum of the wrist (arrowheads) which is heterogenously low signal on all sequences. It shows some peripheral enhancement with gadolinium (Fig. 4c, arrowheads) but no central enhancement (Fig. 4c, long arrow). On the sagittal image, the lesion
Radiology quiz is seen to lie in close approximation to one of the extensor tendons of the back of the wrist (Fig. 4d, long arrow). These features are consistent with a synovial proliferative disorder. These usually arise in the synovium of joints where they are known as pigmented villonodular synovitis (PVNS). The same disease arising in the synovium of a tendon sheath is known as giant cell tumour (as in this example). The lesions consist of histiocytes, hyperplastic synovial elements and giant cells. Haemosiderin deposition occurs and accounts for the low signal seen on all MR sequences. They usually present as a monoarticular arthropathy or a gradually enlarging lump in a young adult. The patient should be referred to a soft tissue sarcoma service for resection. Although the lesion is benign, it has a tendency to recur both at the same site and in neighbouring tendon sheaths.
Answer 5. Scapholunate dissociation (Terry Thomas sign) The distance between the scaphoid and lunate on a plain radiograph should be less than 2 mm. A gap of greater than this (Fig. 5a, arrow; Fig. 5b) indicates scapholunate ligament disruption and scapholunate dissociation. The MR arthrogram images confirm the disruption. Gadolinium is injected at the side of the wrist at the level of the proximal carpal row. The contrast is normally constrained within the radio-ulnar-carpal joint by the intrinsic ligaments of the proximal carpal row. In this patient, the scapholunate ligament disruption has allowed contrast to flow abnormally into the midcarpal joints (Fig. 5b, small arrows). Small fragments of bone can be seen in the gap between scaphoid and lunate as low signal opacities (Fig. 5b, long arrow). The axial image (Fig. 5c) demonstrates the tear directly (long arrow). The residual damaged scapholunate ligament is seen as a ragged piece of tissue (short arrow) surrounded by gadolinium in the widened joint space between the scaphoid (S) and lunate (L). The scapholunate ligament is important for stabilising the wrist joint and damage to it, particularly its dorsal component, can result in dorsal intercalated segment instability (DISI).
Answer 6. Meniscal injury (bucket handle tear) Figure 6a shows a large knee joint effusion, most marked in the suprapatellar pouch (long arrow). The posterior horn of the medial meniscus is small (double arrowhead). It should be at least as big as the anterior horn (arrowhead). Extra meniscal tissue is seen lying anterior to the anterior horn of the medial meniscus (short arrow). Figure 6b shows extra meniscal tissue lying in the intercondylar notch (long arrow) and a tiny residual fragment of meniscal tissue in the medial compartment of the knee (short arrow). Compare with the normal lateral meniscus (arrowhead). These features are consistent with a ‘bucket handle’ tear of the medial meniscus. The ‘bucket handle’ has prolapsed forward and medially and now lies anterior to the anterior horn of the meniscus and in the intercondylar notch. A small remnant of posterior horn is left in the posterior joint. Christopher Hammond, Philip Robinson Department of Radiology, St. James’ University Hospital, Beckett Street, LEEDS LS7 7TF, UK