Use of Magnetic Resonance Neurography for Evaluating the Distribution and Patterns of Chronic Inflammatory Demyelinating Polyneuropathy

OBJECTIVE: To evaluate the distribution and characteristics of peripheral nerve abnormalities in chronic inflammatory demyelinating polyneuropathy (CIDP) using magnetic resonance neurography (MRN) and to examine the diagnostic efficiency.MATERIALS AND METHODS: Thirty-one CIDP patients and 21 controls underwent MR scans. Three-dimensional sampling perfections with application-optimized contrasts using different flip-angle evolutions and T1-/T2- weighted turbo spin-echo sequences were performed for neurography of the brachial and lumbosacral (LS) plexus and cauda equina, respectively. Clinical data and scores of the inflammatory Rasch-built overall disability scale (I-RODS) in CIDP were obtained.RESULTS: The bilateral extracranial vagus (n = 11), trigeminal (n = 12), and intercostal nerves (n = 10) were hypertrophic. Plexus hypertrophies were observed in the brachial plexus of 19 patients (61.3%) and in the LS plexus of 25 patients (80.6%). Patterns of hypertrophy included uniform hypertrophy (17 [54.8%] brachial plexuses and 21 [67.7%] LS plexuses), and multifocal fusiform hypertrophy (2 [6.5%] brachial plexuses and 4 [12.9%] LS plexuses) was present. Enlarged and/or contrast-enhanced cauda equina was found in 3 (9.7%) and 13 (41.9%) patients, respectively. Diameters of the brachial and LS nerve roots were significantly larger in CIDP than in controls (p < 0.001). The largest AUC was obtained for the L5 nerve. There were no significant differences in the course duration, I-RODS score, or diameter between patients with and without hypertrophy.CONCLUSION: MRN is useful for the assessment of distribution and characteristics of the peripheral nerves in CIDP. Compared to other regions, LS plexus neurography is more sensitive for CIDP.

Accessory Belly of the Piriformis Muscle as a Cause of Piriformis Syndrome: a Case Report with Magnetic Resonance Imaging and Magnetic Resonance Neurography Imaging Findings

Piriformis syndrome caused by an accessory belly of the piriformis muscle is very rare. Only a few cases have been reported. Here, we report a case of piriformis syndrome resulting from an extremely rare type of accessory belly of the piriformis muscle originated at the proximal third portion of the main piriformis muscle and attached separately to the greater trochanter inferior to the insertion of the main piriformis muscle. A definitive diagnosis of piriformis syndrome was made based on magnetic resonance imaging and magnetic resonance neurography findings that were consistent with results of nerve conduction study and needle electromyography.

The value of Turbo inversion recovery magnitude (TIRM) magnetic resonance neurography for sacral plexus injury / 中华显微外科杂志

Objective To evaluate the capability of Turbo inversion recovery magnitude (TIRM) magnetic resonance neurography (MRN) in the diagnosie of sacral plexus injury by comparing MRN findings with surgical results.Methods Ten patients with sacral plexus injury confirmed surgically underwent conventional T1WI,T2WI,TIRM and coronal TIRM MRN before operations from June,2011 to December,2012.The MRI data and surgical data were analyzed retrospectively to observe nerve injury.Results The coronal TIRM MRN images displayed 93 trunks of sacral plexus,of which 37 were confirmed injury by operation.The MRI findings were as follows:6 trunks involved continuous nerves,but with thickening and blurred margin,as well as abnormal high signal intensity;22 trunks were continuous,but with distortion,stiffness and adhesion accompanied by heterogeneous signal intensity and structural disorder;3 trunks showed complete loss of continuity,absence of normal signal,accompanied by retraction;and 3 trunks involved formation of traumatic neurofibroma.The coincidence of injured nerve trunks diagnosed by MRN with surgical findings amounts to 81.08％ (30/37).Conclusion MR with coronal TIRM imaging is effective in the diagnosis and depiction of sacral plexus injury,therefore it can be used as conventional sequence in sacral plexus examination to detect sacral plexus avulsion.

Neuralgic Amyotrophy Manifesting as Mimicking Posterior Interosseous Nerve Palsy

The upper trunk of the brachial plexus is the most common area affected by neuralgic amyotrophy (NA), and paresis of the shoulder girdle muscle is the most prevalent manifestation. Posterior interosseous nerve palsy is a rare presentation in patients with NA. It results in dropped finger on the affected side and may be misdiagnosed as entrapment syndrome or compressive neuropathy. We report an unusual case of NA manifested as PIN palsy and suggest that knowledge of clinical NA phenotypes is crucial for early diagnosis of peripheral nerve palsies.

Magnetic Resonance Neurographic Findings in Classic Idiopathic Neuralgic Amyotrophy in Subacute Stage: A Report of Four Cases

Neuralgic amyotrophy (NA) is characterized by acute onset of severe pain, followed by muscular weakness and wasting of the shoulder girdle. While the diagnosis of NA mainly relies on the clinical history and examination, some investigations including electrophysiologic study and radiologic study may help to confirm the diagnosis. Magnetic resonance neurography (MRN), a new technique for the evaluation of peripheral nerve disorders, can be helpful in the diagnosis of NA. MRN presents additional benefits in comparison to conventional magnetic resonance imaging in the diagnosis of idiopathic NA (INA). In this report, we present the first four cases of classic INA diagnosed with MRN in subacute stage. MRN imaging modality should be considered in patients clinically suspected of INA.

Magnetic resonance neurography of lumbar plexus in healthy people / 重庆医科大学学报

Objective:To Compare the difference between the data of normal lumbar plexus nerve measured through magnetic resonance neurography(MRN) with specimen. Methods:Volunteers of 30 healthy lumbar plexus nerve cases(19 males and 11 females) were selected, to measure the short shaft line and neuromuscular signal ratio of the right normal lumbar nerve root, ganglia, nerve and the femoral nerve stem, anatomy and measurements of the right lumbar plexus L2~5 nerve root,ganglia and nerve stem, femoral nerve morphology and size. And comparison of MRN measurement data and autopsy measurement data were conducted. Results:MRN could clearly show L2~5 nerve course, ganglion being circle or Oval enlargement, with the size about 3~6mm;a nerve root and stem displayed strips and smooth edge, with the size about 2~5mm, nerve Festival signal is more than the nerve root and stem. There was no significant statistical difference with the comparability between the obtained data and autopsy ones. Conclusion:MRN can clearly show lumbar plexus and major branches; its measured value can reflect changes in lumbar plexus. It is possible for diagnostic criteria of the lumbar plexus nerve diseases and dysplasia.

The Value of MRI in Diagnosis of Peripheral Nerve Disorders

OBJECTIVE: The development of magnetic resonance neurography(MRN) has made it possible to produce high-resolution images of peripheral nerves themselves, as well as associated intraneural and extraneural lesions. We evaluated the clinical application and utility of high-resolution MRN techniques for the diagnosis and treatment of a variety of peripheral nerve disorder(PND)s. MATERIAL AND METHOD: MRN images were obtained using T1-weighted spin echo, T2-weighted fast spin echo with fat suppression, and short tau inversion recovery(STIR) fast spin-echo pulse sequences. Fifteen patients were studied, three with brachial plexus tumors, five with chronic entrapment syndromes, and seven with traumatic peripheral lesions. Ten patients underwent surgery. RESULTS: In MRN with STIR sequences of axial and coronal imagings, signals of the peripheral nerves with various lesions were detected as fairly bright signals and were discerned from signals of the uninvolved nerves. Increased signal with proximal swelling and distal flattening of the median nerve were seen in all patients of carpal tunnel syndrome. Among the eight patients with brachial plexus injury or tumors, T2-weighted MRN showed increased signal intensity in involved roots in five, enhanced mass lesions in three, and traumatic pseudomeningocele in three. Other associated MRI findings were adjacent bony signal change, neuroma, root adhesion and denervated muscle atophy with signal change. CONCLUSION: MRN with high-resolution imaging can be useful in the preoperative evaluation and surgical planning in patients with peripheral nerve lesions.