Magnetic Resonance Neurography Evaluation in Children

Clinical Neurology Neurology Clinical

on 3T scanners. 2D imaging can be disadvantageous as peripheral nerves the lesions along the axis of the nerve, Magnetic Resonance Neurography obtained similarly on both types of travel in neurovascular bundles. course deviations, focal neuroma, scanners, although it takes a little Use a TR/TE/TF of ~ 3800–4000/60– neurotmesis, etc. and for better pre- Evaluation in Children longer on 1.5T scanners, especially 65/15–25 for T2 SPAIR imaging. operative planning. In extremities, when one tries to attain similar image Sagittal STIR imaging is particularly another 3D imaging, i.e. 3D DW PSIF quality on thin section (2–3 mm) useful in brachial plexus imaging to (diffusion-weighted reversed steady 1, 2 2 2 Avneesh Chhabra, M.D. ; Vibhor Wadhwa, MBBS ; Sahar J. Farahani, M.D., MPH ; scans. High resolution imaging with obtain uniform fat suppression in a state in free precession) is extremely 2 2 Gaurav K. Thawait, M.D. ; John A. Carrino, M.D., MPH combined 2D and 3D isotropic spin difficult neck area and to tease out useful to create nerve specific isotropic echo type imaging is essential for asymmetrical or individual nerve sig- images due to effective fat and vas- 1 University of Texas Southwestern Medical Center, Dallas, TX, USA optimal assessment of small peripheral nal intensity and caliber alterations. cular suppression (TR/TE/SL ~ 12/3/0.9, 2 The Russel H. Morgan Department of Radiology and Radiological Science, nerves. The inability to stay still for Dixon type fat suppression is also b-value for diffusion~60–80 ms and Johns Hopkins University School of Medicine, Baltimore, MD, USA infants and small children makes useful in generating uniform fat water selective fat suppression). imaging more challenging, frequently suppression. Additional coronal T1w, STIR/PD SPAIR requiring sedation or general images aid in detection of lesions 3D images complement information Abstract MR Neurography technique anesthesia for adequate results and along the long axis of the nerves as generated from 2D imaging by show- to avoid repeat acquisition [1]. well as allow assessment of regional Magnetic Resonance Neurography firming and localizing the neuropa- The currently available 3 Tesla scan- ing nerves in longitudinal planes. The joints and musculotendinous struc- has proven to be an excellent tech- thy, but also in ruling out neuropathy ners (MAGNETOM Skyra, Verio and Trio, One should use dedicated coils as far imaging can be obtained using iso- tures. These also serve as fall back nique for the evaluation of peripheral by showing normal appearing nerves Siemens Healthcare, Erlangen, Ger- as possible. For MRN imaging around tropic 3D SPACE (Sampling Perfection sequences, in case the subject moves neuropathies. However, its use in and regional muscles. The authors many) are preferred over 1.5T systems the joints, use joint specific coils, such with Application optimized Contrasts during the scan or if there is failure pediatric age group has been less well describe the MRN technique used in (MAGNETOM Aera and Avanto) due as wrist, elbow, ankle etc. If a joint using variable flip angle Evolutions) of 3D imaging for any reason. IV gad- described. In this article, the authors pediatric age group and discuss a to higher signal-to-noise ratio (SNR) and specific coil is not available, use the technique. A variety of contrasts are olinium contrast is not routinely used discuss the technical considerations, spectrum of peripheral nerve pathol- short imaging times on the higher smallest possible flex coil to cover the available on SPACE sequence, includ- in injury cases, however is useful for various common causes of peripheral ogies that can be observed in chil- field scanners. Additionally 3D imaging expected anatomy. For contiguous ing T1, T2, PD, STIR and SPAIR. Non- differentiating types of neural hyper- neuropathies in children* and the dren using relevant case examples. with fat suppression is better obtained imaging of the joint and extremity, e.g. fat suppressed T2 SPACE (TR/TE/TF ~ trophy such as suspected neoplasm, role of magnetic resonance neurog- wrist and forearm, use wrist coil and 1500–1700/110–120/42–50) is used infection, inflammation, diffuse poly- raphy in their diagnosis and 1 flex coil separately in the adolescent for spine imaging, which is necessary neuropathy, neurocutaneous syn- management. child to avoid excess blank (air) space in plexus evaluation. One can rou- dromes, or post-operative complica- around the extremity. In a child or tinely obtain 0.8–0.9 mm isotropic Introduction tion [7, 8]. infant, a single flex coil can suffice for images through the cervical or lumbar A wide spectrum of peripheral nerve such imaging due to the relatively small spine. In cases of suspected nerve Normal and abnormal pathologies are encountered in chil- size of the extremity. During plexus root avulsions, one should also obtain peripheral nerves dren, including hereditary neuropathy, imaging, use a combination of body 3D CISS imaging focused at spine for traumatic birth injury and motor array on the front and spine elements high resolution (0.6–0.65 mm isotro- Normal peripheral nerves show isoin- vehicle accident, neoplasm, infection on the back to attain uniformity of pic) evaluation of preganglionic nerve tense signal on T1w and T2w images. and inflammation. Clinical features magnetic signal in the field-of-view. rootlets. For post ganglionic nerve On T2 SPAIR images, minimal hyper- in these cases are often nonspecific assessment in plexuses, fat suppressed intensity is normal, especially where High resolution 2D (dimensional) and invasive electrodiagnostic tests, 3D imaging using STIR SPACE (TR/TE/ the nerves curve around the joints. axial T1-weighted (T1w) and T2 SPAIR such as nerve conduction studies are TF/SL ~ 2000–2200/70–80/50–60/ On 3D STIR SPACE images, the nerves (Spectral Adiabatic Inversion Recovery) usually uncomfortable and not feasi- 1.3–1.5 mm isotropic) is most useful. appear uniformly hyperintense in sequences are useful for demonstrat- ble in the pediatric age group. Periph- There is virtually no pulsation artifact the plexuses due to increased sensitiv- ing regional anatomy of the nerve fas- eral nerve imaging can therefore, on the 3D imaging and once thick ity to the endoneurial fluid. Most cicles. Fascicular architecture of nerves be very useful in small children with slab (8–15 mm) maximum intensity hyperintensity is seen at the dorsal is consistently seen with T2 SPAIR strong clinical suspicion in whom projections (MIPs) are created, the nerve root ganglion level and the images in larger branches, such as fem- the diagnosis cannot be firmly estab- image looks smoothened and shows signal fades distally along the course oral nerves and sciatic nerves, as well lished. However, small size of the the high intensity nerves along their of the nerves. Pathological nerves as in smaller nerves that are affected nerves and the relative lack of specific long axis or in any desired arbitrary show one or a combination of find- and enlarged due to neuropathy, such clinical features makes imaging of plane, e.g. oblique sagittal planes are ings, such as increasing hyperintensity as lateral femoral cutaneous and geni- the nerves challenging and requires useful to depict femoral and sciatic approaching the signal of the regional tofemoral nerves [4, 5]. Fluid sensitive high technical skill for performance nerves along their long axes (Fig. 1). vessels and encompassing a long sequences such as STIR (short tau inver- and interpretation. There is a paucity SPAIR SPACE (0.9–1.0 mm isotropic) segment of the nerve; focal or diffuse sion recovery) images have more uni- of literature describing the diagnostic is very useful in extremity imaging due caliber enlargement (more than adja- form fat suppression and higher T2 role of peripheral nerve imaging in to higher SNR and similar uniform fat cent regional nerves, contralateral contrast, especially in the presence children [1-3]. Magnetic Resonance suppression. The nerve perpendicular counterpart nerve or artery in the neu- of metal or in off-center areas [6], Neurography (MRN) is a non-invasive plane shows cross-sectional appear- rovascular bundle); internal fascicular however STIR imaging is often marred imaging technique, which enables ance of the fascicular anatomy of the by low SNR, pulsation artifacts and *MR scanning has not been established as direct visualization of the anatomy nerve. The longitudinal plane along increased baseline nerve signal inten- safe for imaging fetuses and infants less and pathology of the peripheral the long axis of the nerve shows focal 1 Normal LS plexus and sciatics in a young girl. MIP image from coronal 3D STIR sity. SPAIR produces higher SNR images than two years of age. The responsible nerves and regional muscles, thereby SPACE sequence shows normal symmetrical appearance of the LS plexus nerve or diffuse nerve enlargement and mass and are less prone to blood flow arti- physician must evaluate the benefits of aids in localizing the site of injury roots (short arrows) and bilateral sciatic nerves (long arrows). effect of regional perineural lesions the MR examination compared to those facts than STIR imaging, which could be or tumor. It can not only help in con- [1]. 3D imaging is helpful in localizing of other imaging procedures.

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2A 2B 2C are used to complement information Hereditary Neuropathies spreading along the length of the gained from one another to reach a Inherited Neuropathies are a hetero- nerve and involving multiple nerve correct diagnosis. Although ED tests geneous group of pathologies in fascicles. They are more commonly are good for systemic conditions caus- which neuropathy is either the pri- associated with neurofibromatosis ing peripheral neuropathies, they are mary presentation of the disease type 1 (NF-1; 90% cases) than local- highly dependent on clinical and tech- (such as Charcot Marie Tooth dis- ized variants and have a higher pro- nical expertise of the examiner and ease; CMT) or a part of a more gener- pensity to develop malignant PNSTs are not practical in infants or small chil- alized or systemic disorder. The latter later in life. Schwannomas are com- dren, since patient cooperation is group encompasses a large group of monly solitary slow-growing subcuta- imperative to their success [10]. Imag- rare disorders such as familial amy- neous lesions < 5 cm in size. They ing of the nerves as such is of vital loid polyneuropathy (FAP), porphyria, can occasionally be multiple and asso- importance in children for evaluation ataxia telangiectasia and many other ciated with several hereditary neuro- of neuropathies. syndromes. The most common of cutaneous syndromes, most well defined of these being neurofibroma- Non-invasive imaging of nerves can hereditary neuropathies is CMT, which tosis type 2 (NF-2) and Schwannoma- be done using ultrasonography (US) is classified into various types based tosis [17]. or MRN. US is cost effective, portable on pathogenesis – demyelination and allows dynamic assessment of the or axonal degeneration. Clinical fea- On MR imaging, the lesions appear extremity nerves. Large segments tures include muscle denervation 2D 2E 2F isointense on T1w images and show of the nerves can be seen along their changes (weakness, atrophy), high homogenous to heterogenous entire course in the extremities. It plantar arches, impaired sensation and increased signal intensity to muscle does require considerable technical diminished deep tendon reflexes [12, on T2w images. PNSTs have classi- skill and cannot depict subtle changes 13]. The most common form of CMT cally been described using several in signal intensity as with MRN in cases is autosomal dominant demyelinat- imaging signs on MRI. The ‘tail sign’ with mild neuropathy without fascicu- ing CMT (CMT type 1A), which is seen describes a tail forming at the supe- lar enlargement. Deep nerves are diffi- in 70% cases. MR imaging is a useful rior and/or inferior margin of the cult to interrogate using US and mus- adjunct to clinical and electrodiag- nerve lesion. The ‘target sign’ is central cle denervation changes are not nostic suspicion of the neuropathy. hypointense tissue due to collage- apparent till late stage. MRN can evalu- One would see diffuse enlargement nous stroma with peripheral increased ate the nerves, their innervated mus- of bilateral peripheral nerves with signal intensity on T2w images due cles and regional soft tissue structures. abnormally increased signal intensity to more myxomatous tissue. It is With its combined 2D and 3D imaging and/or fascicular prominence in a observed in NF more commonly than symmetric fashion. Most enlargement Surgical failure. Axial T2 SPAIR (2A) image shows enlarged neuromatous common peroneal nerve (CPN) (arrow) following capabilities, it can illustrate neuromus- Schwannoma. The ‘split fat sign’ 2 is observed in CMT type 1A. No sig- placement of nerve tube to bridge the resected mass of the CPN. Axial T2 SPAIR image and T1w images (2B, C) distally show cular anatomy and pathology in multi- means prominent fat around the edema like signal and fatty replacement of the muscles (arrows). Oblique sagittal 3D DW PSIF reconstructed image (2D) ple planes for better interpretation by nificant enhancement is seen on post- slowly growing lesion. The ‘fascicular shows the findings in the long axis with neuromatous proximal nerve (long arrow) and empty nerve tube (short arrow). the radiologist and localize the pathol- contrast imaging. Whole-body MR sign’ depicts prominent fascicular neu- DTI tensor image (2E) and corresponding inverted scale MIP image (2F) show the normal continuous normal tibial nerve ogy for preoperative planning for the Neurography (WBMRN) is likely to be rogenic appearance within the margin (small arrows) and discontinuous CPN with end bulb neuromas (long arrows). referring physician. useful in future to assess the disease of the lesion. The ‘bag of worms’ sign burden in these diffuse polyneuropa- is seen in superficial plexiform NFs Spectrum of peripheral thy cases [14]. Nerve biopsy is the [17, 18]. While NF may show multi- neuropathies in children most accurate test to diagnose CMT, fascicular involvement of the nerves, however it is rarely necessary these enlargement, effacement or atrophy; inflammation, neoplastic and trauma Advantages of MRN The causes of neuropathies differ schwannoma shows one or two fas- days. intra-epineural fat deposition; epineu- causes. On the other hand, adults between adults and children. More than cicular continuity with the mass lesion. MRN is particularly useful in children rial or perineurial thickening; perineu- usually suffer from neuropathies sec- 70% of neuropathies in children are Neoplastic It is difficult to differentiate between due to frequent inability of electrodi- ral fibrosis with or without nerve ondary to entrapment, toxic insult related to inherited causes, while most benign and malignant PNSTs on con- agnostic studies (EDS) to yield diag- The most common peripheral nerve entanglement; nerve displacement or systemic disease, such as diabetes. cases of neuropathy in adults are ventional MRI. Diffusion tensor imag- nostic information. Moreover, MRN is sheath tumors (PNSTs) in children are due to mass lesion; heterogeneous It is thus important to understand acquired (60%). Adults with acquired ing showing low minimum apparent not operator dependent and can local- neurofibromas (NF) and schwanno- nerve thickening suggesting a neu- the differing etiology in adults and neuropathy are mostly related to diffusion coefficient (ADC) value ize the exact site of nerve pathology. mas [15]. These are benign tumors -3 2 roma in continuity or end bulb neu- children in order to make a proper trauma, entrapment or chronic injury (< 1.1 × 10 mm /s) is useful to find It provides useful data for preoperative arising from the Schwann cells, with roma from complete rupture or fail- diagnostic plan for evaluation of from sports or occupation. In children, most cellular areas that may suggest planning and postoperative response additional non-neoplastic cells includ- ure of nerve regeneration (Fig. 2); peripheral neuropathies in pediatric acquired neuropathies are more likely malignancy and can be directed for to surgical treatment even before clini- ing neurons, perineurial cells and and finally, regional muscle denerva- age group. MR Neurography is indi- secondary to infection and inflamma- biopsy. In underlying neurofibroma- cal and functional improvement is endoneurial fibroblasts [16]. NFs may tion changes, which by definition are cated in children with suspected but tion [11]. Clinically, neuropathy results tosis, there is increased chance of noticeable [1]. The EDS give vital physi- be described as localized, diffuse or distal to the site of the entrapment unclear underlying hereditary or in numbness, pain, paresthesia and malignancy and it may develop at an ologic information about the nerve plexiform. Most of NFs are of localized [2, 4-6]. acquired pathology that may cause weakness of the innervated muscles. earlier age in life as compared to the pathology by evaluating nerve conduc- variant seen as small (< 5 cm) fusi- neuropathy, known neuropathy with- In small children these symptoms may isolated forms of malignant periph- Indications tion velocity or muscle action poten- form masses involving a superficial out any identifiable underlying cause, be less noticeable, and thus reflex test- eral nerve sheath tumors. New onset tials using electromyography [9]. On the or major peripheral nerve. Plexiform Hereditary neuropathy is the most and to characterize neuropathy in ing is of vital importance. Following of severe pain, neurologic deficit, other hand, imaging studies primarily NF, on the other hand, comprises pro- common etiology in children. Acquired cases of infection, inflammation is a discussion of various common rapid increase in size, heterogeneous evaluate the anatomy and results of liferation of cells in the nerve sheath cases can be seen due to infection, or trauma. causes of peripheral neuropathies. appearance and low ADC value can nerve pathology. Both these modalities

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3A 3B This complicates the regeneration 4A 4B 3 process and may lead to dysfunctional distal end of the nerve. Young girl with NF type I and MPNST. MIP • Grade IV injury results in neuroma images from coronal -in-continuity (NIC), which encom- 3D STIR SPACE (3A, B) passes perineurial disruption and show numerous entangled disorganized mass of peripheral nerve regenerating nerve fibers. sheath tumors and • Sunderland grade V injury leads to nodular thickening of end-bulb neuroma, also called stump the sciatic nerves (arrows in 3A) and a neuroma with underlying discontinu- large heterogeneous ity with the nerve (Sunderland MPNST arising of the Grade V) [17, 21]. right femoral nerve On MR imaging, NIC appears as a (arrow in 3B) in this heterogeneous mass with ‘tail sign’ known case of NF type I. which does not show enhancement on ADC image (3C) from contrast administration (differentiat- DTI shows a low value ing it from neurogenic tumor, which of 0.7 × 10-3 mm2/s in 4C 4D keeping with high shows enhancement). Stump neuromas cellularity. Contrast fat are seen as fusiform masses with an 3C 3D suppressed T1w VIBE irregular outline showing decreased image shows hetero- signal intensity on T1w images and geneous nodular increased signal intensity on T2w enhancement with images [21]. MRN can clearly show central necrosis (arrow). abnormal nerve hyperintensity and/or enlargement with otherwise underlying nerve continuity in Grade I-III injuries, which undergo medical management, except that one might release super- imposed nerve entrapment. Grade IV and V injuries show a focal neuroma and these can also be distinguished 4 Young girl with gradual left leg weakness caused by a Perineurioma. MIP images from based on the presence of nerve conti- coronal and oblique sagittal reconstructed 3D STIR SPACE (4A, B) images show left nuity or discontinuity. femoral nerve (small arrows) fusiform enlargement by a perineurioma (long arrows). DTI images show ADC value of 1.1 × 10-3 mm2/sec. Infection / Inflammation Infectious neuropathy may result from direct nerve involvement or immuno- 5A 5B logic response of the body towards the infectious agent. The most common and important of these is the Guillain- serve as important signs of incipient in children occur in the upper extrem- axon with preservation of outer Barre Syndrome (GBS), also known malignancy (Fig. 3). Perineurioma is ity, and the most common causes covering layers of endoneurium, as acute inflammatory demyelinating another classic benign tumor, seen in include obstetric lesions (46.78 %) perineurium and epineurium. polyneuropathy (AIDP). Various micro- young children in their adolescence (Fig. 5) and iatrogenic (16.95 %), with Wallerian degeneration follows such organisms have been implicated as showing uniform fascicular thickening predominant involvement of the an insult, which later results in regen- the trigger for the immune response and nerve thickening over a long seg- brachial plexus and sciatic nerve [19]. eration of the axon along its original in GBS (Campylobacter jejuni, Cytomeg- ment, usually in a sciatic distribution. course as the nerve coverings are alovirus and Ebstein Barr virus, etc.). Sunderland classified peripheral Due to compact fascicular thickening, preserved. Although the duration and GBS is a clinical diagnosis classically nerve injuries into five grades of it may show ADC values in the range severity of symptoms is worse, it presenting in the child after a recent increasing severity [20]. of 1.0–1.2 × 10-3 mm2/s, however, the usually carries an excellent prognosis mild infection with weakness, sensory • Neurapraxia (Sunderland Grade I) is clinical symptoms of slow motor loss similar to neurapraxia. loss, pain, and hypoflexia in the lower a mild form of neural insult leading and MRN imaging appearance are • Neurotmesis (Sunderland Grade III) extremities. MR imaging is usually to temporary impulse conduction 5 Left C7 nerve root avulsion in an infant from birth injury. Sagittal T2w SPACE (5A) classic findings (Fig. 4). refers to complete disruption of ordered in such cases to confirm the block along the affected nerve seg- image and MIP image from coronal 3D STIR SPACE (5B) show pseudomeningocele the axon and supporting connective diagnosis and more importantly to rule of the left C6-7 neural foramen with left C7 nerve root avulsion (arrows). Trauma ment. It is reversible and muscle tissue structures. There is loss of out other spinal cord or nerve root denervation changes do not occur. Traumatic peripheral nerve injuries continuity of the nerve fibers, and pathologies that mimic AIDP. MRI find- • Axonotmesis (Sunderland Grade II) are common in both children and the regenerating nerve fibers are no ings may be normal in pediatric patients. is more severe than neuraplaxia adults, albeit the causes are different. longer confined to the endoneurium. Hyperintensity and nerve thickening About 80% peripheral nerve injuries involving physical disruption of the

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6A on MRN images may be seen in spinal References 1 Cortes C, Ramos Y, Restrepo R, Restrepo JA, nerve problems in the upper and lower 19 Uzun N, Tanriverdi T, Savrun FK, Kiziltan 6 nerve roots as a result of the inflammatory process, showing enhancement Grossman JA, Lee EY. Practical magnetic extremity using quantitative sensory ME, Sahin R, Hanimoglu H, et al. Traumatic CIDP. Young boy with resonance imaging evaluation of peripheral testing. Hand Clin. 1999;15(4):697-715. peripheral nerve injuries: demographic on contrast imaging. The anterior left arm weakness and nerves in children: magnetic resonance 10 Chemali KR, Tsao B. Electrodiagnostic and electrophysiologic findings of 802 mild sensory changes. nerve roots show enhancement more neurography. Radiol Clin North Am. testing of nerves and muscles: when, why, patients from a developing country. J Clin Axial T2w SPAIR (6A) frequently than posterior nerve roots, 2013;51(4):673-88. and how to order. Cleve Clin J Med. Neuromuscul Dis. 2006;7(3):97-103. and T1w (6B) images which is suggestive of GBS [22, 23]. 2 Merlini L, Vargas MI, Anooshiravani M, 2005;72(1):37-48. 20 Sunderland S. The anatomy and physiology show multifocal thick- Viallon M, Fluss J, Hanquinet S. Look for 11 Pavone P, Pratico AD, Ruggieri M, Verrotti of nerve injury. Muscle Nerve. 1990; ening and prominent Chronic inflammatory demyelinating the nerves! MR neurography adds essential A, Castellano-Chiodo D, Greco F, et al. 13(9):771-84. fascicular appearance polyneuropathy (CIDP) is also an diagnostic value to routine MRI in pediatric Acquired peripheral neuropathy: a report 21 Chhabra A, Williams EH, Wang KC, of all brachial plexus immune mediated condition which practice: a pictorial overview. J Neuro- on 20 children. Int J Immunopathol Dellon AL, Carrino JA. MR neurography peripheral branch presents similar to GBS and is differen- radiol. 2011;38(3):141-7. Pharmacol. 2012;25(2):513-7. of neuromas related to nerve injury and nerves (arrows). tiated from GBS on basis of course of 3 Merlini L, Viallon M, De Coulon G, Lobrinus 12 Skre H. Genetic and clinical aspects of entrapment with surgical correlation. Sagittal fs PDw (6C) the disease (progressive worsening JA, Vargas MI. MRI neurography and Charcot-Marie-Tooth’s disease. Clin Genet. AJNR Am J Neuroradiol. image shows most diffusion tensor imaging of a sciatic 1974;6(2):98-118. 2010;31(8):1363-8. for more than 2 months, while GBS is thickening of median perineuroma in a child. Pediatr Radiol. 13 Gaeta M, Mileto A, Mazzeo A, Minutoli F, 22 Byun WM, Park WK, Park BH, Ahn SH, nerve (long arrow) self-limiting, lower limb involvement 2008;38(9):1009-12. Di Leo R, Settineri N, et al. MRI findings, Hwang MS, Chang JC. Guillain-Barre 6B and less pronounced > upper limbs and high CSF protein). 4 Wadhwa V, Thakkar RS, Maragakis N, patterns of disease distribution, and syndrome: MR imaging findings of the thickening of the MR imaging findings in CIDP are non- Hoke A, Sumner CJ, Lloyd TE, et al. Sciatic muscle fat fraction calculation in five spine in eight patients. Radiology. musculocutaneous specific showing mild to moderate dif- nerve tumor and tumor-like lesions – patients with Charcot-Marie-Tooth type 2 1998;208(1):137-41. nerve (small arrow) fuse enlargement with increased cross uncommon pathologies. Skeletal Radiol. F disease. Skeletal Radiol. 23 Yikilmaz A, Doganay S, Gumus H, Per H, and axillary nerve sectional area of the nerve, as with 2012;41(7):763-74. 2012;41(5):515-24. Kumandas S, Coskun A. Magnetic (medium arrow). 5 Chhabra A, Faridian-Aragh N. High- 14 Yamashita T, Kwee TC, Takahara T. Whole- resonance imaging of childhood Guillain- other hereditary neuropathies such as resolution 3-T MR neurography of femoral body magnetic resonance neurography. Barre syndrome. Childs Nerv Syst. CMT. However, family history is gener- neuropathy. AJR Am J Roentgenol. N Engl J Med. 2009;361(5):538-9. 2010;26(8): 1103-8. ally insignificant, the lesions may be 2012;198(1):3-10. 15 Murphey MD, Smith WS, Smith SE, 24 Koller H, Kieseier BC, Jander S, Hartung asymmetrical or unilateral (Fig. 6) as 6 Chhabra A, Lee PP, Bizzell C, Soldatos T. Kransdorf MJ, Temple HT. From the HP. Chronic inflammatory demyelinating compared to CMT type IA [4, 24]. 3 Tesla MR neurography-technique, archives of the AFIP. Imaging of musculo- polyneuropathy. N Engl J Med. 2005; Multifocal motor neuropathy is another interpretation, and pitfalls. Skeletal Radiol. skeletal neurogenic tumors: radiologic- 352(13): 1343-56. condition that affects the motor func- 2011;40(10):1249-60. pathologic correlation. Radiographics. 7 Thawait SK, Chaudhry V, Thawait GK, 1999;19(5):1253-80. tion predominantly and is more com- Wang KC, Belzberg A, Carrino JA, et al. 16 Ferner RE, O’Doherty MJ. Neurofibroma mon in upper limbs as compared to the High-resolution MR neurography of diffuse and schwannoma. Curr Opin Neurol. lower limbs. Multiple conduction blocks peripheral nerve lesions. AJNR Am J Neuro- 2002;15(6):679-84 are noted on electrodiagnostic exami- radiol. 2011;32(8):1365-72. 17 Wadhwa V, Lee PP, Strome GM, Suh KJ, 6C nations and MRN of the extremity or 8 Chhabra A, Soldatos T, Durand DJ, Carrino Carrino JA, Chhabra A. Spectrum of plexus shows diffuse nerve thickening JA, McCarthy EF, Belzberg AJ. The role superficial nerve-related tumor and tumor- and/or enlargement, not limited to of magnetic resonance imaging in the like lesions: MRI features. Acta Radiol. diagnostic evaluation of malignant 2013. the entrapment sites. There is generally peripheral nerve sheath tumors. Indian 18 Lim R, Jaramillo D, Poussaint TY, Chang Y, good response to IVIG treatment or J Cancer. 2011;48(3):328-34. Korf B. Superficial neurofibroma: a lesion cyclophosphamide therapy. 9 Dellon AL. Management of peripheral with unique MRI characteristics in patients with neurofibromatosis type 1. AJR Am J Conclusion Roentgenol. 2005;184(3):962-8. Imaging of nerves in children is challenging due to their small size and comparative rarity of neuropathies affecting them. MR Neurography is Contact a powerful diagnostic tool even in Avneesh Chhabra, M.D. pediatric population. With proper Associate Professor Radiology communication between the referring & Orthopaedic Surgery physician and the radiologist, the Section Chief, Musculoskeletal Radiology diagnostic value of MRN is enhanced UT Southwestern Medical Center leading to early diagnosis and proper 5323 Harry Hines Blvd patient care. Dallas, TX 75390-9178, USA Acknowledgement [email protected] Adjunct Professor, Johns Hopkins University Thanks to Anshita Khanna, University of Toronto for literature search support.

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