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Peroneal nerve: Normal anatomy and pathologic findings on routine MRI of the knee.

Van den Bergh FR, Vanhoenacker FM, De Smet E, Huysse W, Verstraete KL - Insights Imaging (2013)

Bottom Line: Axial T1-weighted sequences are especially helpful as they allow a good differentiation between the nerve and the surrounding fat.The purpose of this article is to review the normal anatomy and pathologic conditions of the peroneal nerve around the knee.In the second part we discuss the different pathologic conditions: accidental and surgical trauma, and intraneural and extraneural compressive lesions. • Six anatomical features contribute to the vulnerability of the peroneal nerve around the knee. • MR signs of muscle denervation within the anterior compartment are important secondary signs for evaluation of the peroneal nerve. • The most common lesions of the peroneal nerve are traumatic or compressive. • Intraneural ganglia originate from the proximal tibiofibular joint. • Axial T1-weighted images are the best sequence to visualise the peroneal nerve on routine MRI.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, AZ Sint-Maarten Duffel-Mechelen, campus Duffel, Rooienberg 25, 2570, Duffel, Belgium.

ABSTRACT

Background: Peroneal nerve lesions are not common and are often exclusively assessed clinically and electromyographically.

Methods: On a routine MR examination without dedicated MR-neurography sequences the peroneal nerve can readily be assessed. Axial T1-weighted sequences are especially helpful as they allow a good differentiation between the nerve and the surrounding fat.

Results: The purpose of this article is to review the normal anatomy and pathologic conditions of the peroneal nerve around the knee.

Conclusion: In the first part the variable anatomy of the peroneal nerve around the knee will be emphasized, followed by a discussion of the clinical findings of peroneal neuropathy and general MR signs of denervation. Six anatomical features may predispose to peroneal neuropathy: paucity of epineural tissue, biceps femoris tunnel, bifurcation level, superficial course around the fibula, fibular tunnel and finally the additional nerve branches. In the second part we discuss the different pathologic conditions: accidental and surgical trauma, and intraneural and extraneural compressive lesions.

Teaching points: • Six anatomical features contribute to the vulnerability of the peroneal nerve around the knee. • MR signs of muscle denervation within the anterior compartment are important secondary signs for evaluation of the peroneal nerve. • The most common lesions of the peroneal nerve are traumatic or compressive. • Intraneural ganglia originate from the proximal tibiofibular joint. • Axial T1-weighted images are the best sequence to visualise the peroneal nerve on routine MRI.

No MeSH data available.


Related in: MedlinePlus

Malignant peripheral nerve sheath tumour with atypical features. This patient presented with a painful swelling on the lateral side of the right leg. The initial diagnosis after biopsy was a benign cystic lesion. Coronal T1-WI (a) showing a lesion with a signal intensity almost isointense to the surrounding muscle (arrow). Axial fat-suppressed PD WI (b) shows almost homogeneous hyperintense signal (arrow) in the lesion with a thin hypointense rim. Axial T1-WI (c) after IV administration of gadolinium shows absence of enhancement (arrow). EMG was not performed in this case, as the diagnosis of a malignant PNST was confirmed histologically and the nerve would certainly be sacrificed during surgery. The sometimes misleading cystic appearance of soft tissue tumours is discussed in more detail in the text
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Fig13: Malignant peripheral nerve sheath tumour with atypical features. This patient presented with a painful swelling on the lateral side of the right leg. The initial diagnosis after biopsy was a benign cystic lesion. Coronal T1-WI (a) showing a lesion with a signal intensity almost isointense to the surrounding muscle (arrow). Axial fat-suppressed PD WI (b) shows almost homogeneous hyperintense signal (arrow) in the lesion with a thin hypointense rim. Axial T1-WI (c) after IV administration of gadolinium shows absence of enhancement (arrow). EMG was not performed in this case, as the diagnosis of a malignant PNST was confirmed histologically and the nerve would certainly be sacrificed during surgery. The sometimes misleading cystic appearance of soft tissue tumours is discussed in more detail in the text

Mentions: MPNSTs are heterogeneous on both T1-WI and T2-WI and after contrast administration, with dark areas corresponding to calcifications and hyperintense areas on T2-WI to central necrosis. Three imaging signs are suggestive of a MPNST: size more than 5 cm (the average size of neurofibroma [42, 43]), heterogeneous appearance due to intratumoral bleeding and areas of necrosis [36, 42] and infiltrative margin [43]. Atypical presentation can occur and any other sarcoma may mimic a MPNST (Figs. 13 and 14). Myxoid tumours may mimic cystic lesions. If there is any suspicion of a malignant lesion, intravenous administration of gadolinium contrast should be performed. True cystic lesions will only show minor peripheral rim enhancement, whereas a heterogeneous enhancement pattern is seen in myxoid or malignant tumours with cystic areas [44].Fig. 13


Peroneal nerve: Normal anatomy and pathologic findings on routine MRI of the knee.

Van den Bergh FR, Vanhoenacker FM, De Smet E, Huysse W, Verstraete KL - Insights Imaging (2013)

Malignant peripheral nerve sheath tumour with atypical features. This patient presented with a painful swelling on the lateral side of the right leg. The initial diagnosis after biopsy was a benign cystic lesion. Coronal T1-WI (a) showing a lesion with a signal intensity almost isointense to the surrounding muscle (arrow). Axial fat-suppressed PD WI (b) shows almost homogeneous hyperintense signal (arrow) in the lesion with a thin hypointense rim. Axial T1-WI (c) after IV administration of gadolinium shows absence of enhancement (arrow). EMG was not performed in this case, as the diagnosis of a malignant PNST was confirmed histologically and the nerve would certainly be sacrificed during surgery. The sometimes misleading cystic appearance of soft tissue tumours is discussed in more detail in the text
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3675257&req=5

Fig13: Malignant peripheral nerve sheath tumour with atypical features. This patient presented with a painful swelling on the lateral side of the right leg. The initial diagnosis after biopsy was a benign cystic lesion. Coronal T1-WI (a) showing a lesion with a signal intensity almost isointense to the surrounding muscle (arrow). Axial fat-suppressed PD WI (b) shows almost homogeneous hyperintense signal (arrow) in the lesion with a thin hypointense rim. Axial T1-WI (c) after IV administration of gadolinium shows absence of enhancement (arrow). EMG was not performed in this case, as the diagnosis of a malignant PNST was confirmed histologically and the nerve would certainly be sacrificed during surgery. The sometimes misleading cystic appearance of soft tissue tumours is discussed in more detail in the text
Mentions: MPNSTs are heterogeneous on both T1-WI and T2-WI and after contrast administration, with dark areas corresponding to calcifications and hyperintense areas on T2-WI to central necrosis. Three imaging signs are suggestive of a MPNST: size more than 5 cm (the average size of neurofibroma [42, 43]), heterogeneous appearance due to intratumoral bleeding and areas of necrosis [36, 42] and infiltrative margin [43]. Atypical presentation can occur and any other sarcoma may mimic a MPNST (Figs. 13 and 14). Myxoid tumours may mimic cystic lesions. If there is any suspicion of a malignant lesion, intravenous administration of gadolinium contrast should be performed. True cystic lesions will only show minor peripheral rim enhancement, whereas a heterogeneous enhancement pattern is seen in myxoid or malignant tumours with cystic areas [44].Fig. 13

Bottom Line: Axial T1-weighted sequences are especially helpful as they allow a good differentiation between the nerve and the surrounding fat.The purpose of this article is to review the normal anatomy and pathologic conditions of the peroneal nerve around the knee.In the second part we discuss the different pathologic conditions: accidental and surgical trauma, and intraneural and extraneural compressive lesions. • Six anatomical features contribute to the vulnerability of the peroneal nerve around the knee. • MR signs of muscle denervation within the anterior compartment are important secondary signs for evaluation of the peroneal nerve. • The most common lesions of the peroneal nerve are traumatic or compressive. • Intraneural ganglia originate from the proximal tibiofibular joint. • Axial T1-weighted images are the best sequence to visualise the peroneal nerve on routine MRI.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, AZ Sint-Maarten Duffel-Mechelen, campus Duffel, Rooienberg 25, 2570, Duffel, Belgium.

ABSTRACT

Background: Peroneal nerve lesions are not common and are often exclusively assessed clinically and electromyographically.

Methods: On a routine MR examination without dedicated MR-neurography sequences the peroneal nerve can readily be assessed. Axial T1-weighted sequences are especially helpful as they allow a good differentiation between the nerve and the surrounding fat.

Results: The purpose of this article is to review the normal anatomy and pathologic conditions of the peroneal nerve around the knee.

Conclusion: In the first part the variable anatomy of the peroneal nerve around the knee will be emphasized, followed by a discussion of the clinical findings of peroneal neuropathy and general MR signs of denervation. Six anatomical features may predispose to peroneal neuropathy: paucity of epineural tissue, biceps femoris tunnel, bifurcation level, superficial course around the fibula, fibular tunnel and finally the additional nerve branches. In the second part we discuss the different pathologic conditions: accidental and surgical trauma, and intraneural and extraneural compressive lesions.

Teaching points: • Six anatomical features contribute to the vulnerability of the peroneal nerve around the knee. • MR signs of muscle denervation within the anterior compartment are important secondary signs for evaluation of the peroneal nerve. • The most common lesions of the peroneal nerve are traumatic or compressive. • Intraneural ganglia originate from the proximal tibiofibular joint. • Axial T1-weighted images are the best sequence to visualise the peroneal nerve on routine MRI.

No MeSH data available.


Related in: MedlinePlus