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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: 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.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

Myxoid liposarcoma compressing the peroneal nerve. Because the patient had café au lait spots, a diagnosis of a malignant PNST in a patient with NF1 was initially proposed, with the request for pathological confirmation. Coronal fat-suppressed PD T2-WI (a) shows a polylobulated homogenously hyperintense mass (thin arrows) mostly located in the lateral compartment of the left lower leg, larger than 5 cm. Axial T1-WI (b) shows the mass (arrowheads) extending in the anterior, lateral and deep posterior compartment. Note scalloping on the anterior side of the fibula (thick arrow) and the lateral side of the tibia (curved arrow). Axial T2-WI (c) shows a heterogeneous mostly hyperintense signal in the mass (asterisk), clearly delineating it from the surrounding muscle. There is no fat plane between the soleus muscle and the superficial posterior compartment (arrow), strongly suggesting extension in all four compartments of the lower leg. No muscle oedema is present. Coronal fat-suppressed T1-WI after IV administration of gadolinium contrast (d) shows inhomogeneous peripheral enhancement of the mass (arrows)
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Fig14: Myxoid liposarcoma compressing the peroneal nerve. Because the patient had café au lait spots, a diagnosis of a malignant PNST in a patient with NF1 was initially proposed, with the request for pathological confirmation. Coronal fat-suppressed PD T2-WI (a) shows a polylobulated homogenously hyperintense mass (thin arrows) mostly located in the lateral compartment of the left lower leg, larger than 5 cm. Axial T1-WI (b) shows the mass (arrowheads) extending in the anterior, lateral and deep posterior compartment. Note scalloping on the anterior side of the fibula (thick arrow) and the lateral side of the tibia (curved arrow). Axial T2-WI (c) shows a heterogeneous mostly hyperintense signal in the mass (asterisk), clearly delineating it from the surrounding muscle. There is no fat plane between the soleus muscle and the superficial posterior compartment (arrow), strongly suggesting extension in all four compartments of the lower leg. No muscle oedema is present. Coronal fat-suppressed T1-WI after IV administration of gadolinium contrast (d) shows inhomogeneous peripheral enhancement of the mass (arrows)

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)

Myxoid liposarcoma compressing the peroneal nerve. Because the patient had café au lait spots, a diagnosis of a malignant PNST in a patient with NF1 was initially proposed, with the request for pathological confirmation. Coronal fat-suppressed PD T2-WI (a) shows a polylobulated homogenously hyperintense mass (thin arrows) mostly located in the lateral compartment of the left lower leg, larger than 5 cm. Axial T1-WI (b) shows the mass (arrowheads) extending in the anterior, lateral and deep posterior compartment. Note scalloping on the anterior side of the fibula (thick arrow) and the lateral side of the tibia (curved arrow). Axial T2-WI (c) shows a heterogeneous mostly hyperintense signal in the mass (asterisk), clearly delineating it from the surrounding muscle. There is no fat plane between the soleus muscle and the superficial posterior compartment (arrow), strongly suggesting extension in all four compartments of the lower leg. No muscle oedema is present. Coronal fat-suppressed T1-WI after IV administration of gadolinium contrast (d) shows inhomogeneous peripheral enhancement of the mass (arrows)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3675257&req=5

Fig14: Myxoid liposarcoma compressing the peroneal nerve. Because the patient had café au lait spots, a diagnosis of a malignant PNST in a patient with NF1 was initially proposed, with the request for pathological confirmation. Coronal fat-suppressed PD T2-WI (a) shows a polylobulated homogenously hyperintense mass (thin arrows) mostly located in the lateral compartment of the left lower leg, larger than 5 cm. Axial T1-WI (b) shows the mass (arrowheads) extending in the anterior, lateral and deep posterior compartment. Note scalloping on the anterior side of the fibula (thick arrow) and the lateral side of the tibia (curved arrow). Axial T2-WI (c) shows a heterogeneous mostly hyperintense signal in the mass (asterisk), clearly delineating it from the surrounding muscle. There is no fat plane between the soleus muscle and the superficial posterior compartment (arrow), strongly suggesting extension in all four compartments of the lower leg. No muscle oedema is present. Coronal fat-suppressed T1-WI after IV administration of gadolinium contrast (d) shows inhomogeneous peripheral enhancement of the mass (arrows)
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: 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.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