臂丛神经节前损伤的脊髓造影后CT诊断

目的 评价脊髓造影后CT扫描(CTM)诊断臂丛神经节前损伤的临床应用。方法 27例臂丛神经损伤患者术前做脊髓造影后，使用GE CT／e单排螺旋CT机薄层螺旋扫描，骨重建获取影像。由高年资医生阅片做CTM影像诊断，临床臂丛神经探查术及术后随访结果作为金标准计算CTM诊断的准确性。结果 臂丛神经节前损伤CTM的直接征象是：椎管内不同节段患侧颈神经根充盈缺损连续性消失，共91个。间接征象为：(1)假性脊膜膨出：患侧硬膜囊失去正常形态，为片状高密度影替代，并可沿椎间孔向外延伸，形成神经根鞘膜囊肿，与蛛网膜下腔间有细线状分隔44个。(2)蛛网膜囊肿：硬膜囊一侧膨大变形呈囊样扩张，与蛛网膜下腔间无细线状分隔17个。(3)蛛网膜下腔不对称：一侧腔变窄，脊髓有或无移位27个。(4)硬膜囊壁不完整：一侧囊腔闭锁，脊髓表面部分裸露3个。直接征象阳性，加上间接征象之一，则诊断为臂丛神经节前损伤。27例患者CTM共检出神经根128个，诊断神经根损伤91个，正常37个。手术及随访证实真阳性84个，假阳性7个，真阴性34个，假阴性3个。CTM检查的敏感度、特异度及准确度分别为96．6％、82．9％及92．2％。结论 CTM可以清楚显示臂丛神经节前段并准确诊断其损伤和部位。     

臂丛神经及神经根鞘撕裂伤的脊髓造影CT诊断与临床价值

目的 探讨脊髓造影CT(CTM)诊断臂丛神经撕裂伤的临床价值.方法 16例臂丛神经损伤患者行CTM.全部患者与临床手术探查对照,7例术前行电生理学检查.结果 本组共检出28个受损神经根,其中26个诊断准确,准确率为92.8%.神经根撕裂伤的主要征象是椎管内神经前、后支充盈缺损消失,间接征象为假性硬膜囊肿,脊髓移位与变形,神经根扭曲.结论 CTM对臂丛神经根损伤的诊断具有重要价值.     

MRI在臂丛神经节前损伤诊断中的应用

目的 探讨臂丛神经节前损伤的MRI表现及其诊断价值.方法 回顾性分析20例临床诊断为臂丛神经节前损伤患者的临床和影像资料.所有患者手术前均行MR检查,后行锁骨上手术探查及术中肌电图(EMG)检查,将手术探查所见、EMG检杳结果与MRI结果比较,并统计MRI诊断臂丛神经节前损伤的准确性、敏感忡及特异性.结果 20例患者计入统计的73对受损神经根中MRI 共检出63对,诊断的准确性、敏感性及特异性分别为86.5/(83/96)、86.3/(63/73)、87.0/(20/23).臂丛神经节衣前损伤的直接征象包括:(1)椎管内神经根消失或离断54 X4(85.7/);(2)脊神经前后根增粗、迂曲、走行僵硬无法连续追踪至椎间孔处9对(14.3/).间接征象包括:(1)椎管内脑脊液囊性聚集,假性脊膜膨出 46对(73.0/);(2)神经根袖形态异常13 对(20.6/);(3)脊髓变形、移位50对(79.4/);(4)脊柱旁肌信号异常19例.结论 MRI可很好地显示椎管内及椎间孔区神经根结构,对臂从神经节前损伤町作出准确诊断,为早期诊断臂从神经节前损伤提供可靠参考.     

臂丛神经根损伤的MR诊断及其应用价值

臂丛神经损伤的诊断一直是一个值得研究的课题［１］。对臂丛节前还是节后神经损伤的准确判断是确定治疗方案和估计预后的关键［２］,目前尚无很好方法。笔者通过分析４２例臂丛神经根损伤的ＭＲ影像资料,并与其中１４例脊髓造影和脊髓造影后ＣＴ（ＣＴＭ）比较,评价ＭＲ对神经根损伤的诊断价值。资料与方法１．一般资料：共收集１９９３年３月～１９９６年４月间臂丛神经损伤的ＭＲ资料４２例,其中１４例同时行脊髓造影和ＣＴＭ检查。男３８例,女４例;年龄１个月～４９岁。病史１天～１．５年．骑摩托车摔伤２０例,产伤２例,其他伤…     

颈神经根撕脱损伤:硬膜内神经根增强的MR影像

为研究硬膜内神经根在颈部神经根撕脱损伤的MR影像特征,对27例病人行钆剂增强。男性25例,女性2例。年龄16～51岁。所有病人均为摩托车意外造成。颈椎MR影像由矫正外科医生做术前评估。各种检查在损伤6个月内和臂丛手术前完成。所有病人经一系列的神经科检查,常规脊髓造影,和/或CT脊髓造影检查。25例病人经臂丛外科     

臂丛神经根损伤的诊断:颈段椎管造影CTM和MRI的对比研究

本文研究13例经手术证实的臂丛神经根损伤患者的椎管碘水造影、CTM 和MRI 影像学特点,比较三种检查方法的阳性检出率和诊断正确率,探讨三种检查方法的利弊,其中MRI 对臂丛神经根损伤的发现率与诊断正确率最高,但在MRI 尚未普及时,则椎管碘水造影与CTM 结合应用为诊断臂丛神经根损伤的最佳选择。     

动态MRI对臂丛根性损伤和颈髓损伤的鉴别诊断意义

目的探讨动态MRI诊断臂丛神经根性损伤的影像学表现及其诊断价值，以及在与颈髓损伤的鉴别诊断中的临床意义。方法对8例臂丛神经根性损伤患者行动态MRI检查，结合CT薄层扫描和肌电图随访；所有8例患者均手术证实为臂丛根性损伤。结果本组患者在伤后早期1～2d内均无位于椎间孔及椎间孔外的创伤性脊膜囊肿、神经根断裂等支持臂丛根性损伤的MRI异常表现；4例患者有颈椎骨折或颈髓损伤的MRI表现。伤后7～15d（平均10d）后，再次行颈椎MRI检查，出现典型的MRI臂丛根性损伤表现：椎间孔及椎孔外臂丛神经走行处T2WI高信号的创伤性脊膜囊肿、脊髓移位和神经根缺失及走行异常等。结论动态MRI检查对臂丛根性神经损伤具有损伤节段定位准确、椎管外部分同样能够显示、无创、操作简单、准确性高等特点；其短期内特征性的动态变化易于诊断臂丛根性损伤，同时又能与颈髓损伤相鉴别。     

椎管内臂丛神经根损伤及损伤类型MRI诊断价值研究

目的 将MRI与CTM进行对比,探讨Balance SSFP序列在臂丛椎管内神经根损伤及损伤类型诊断中的临床应用价值.方法 可疑椎管内臂丛神经根损伤的病例中挑选符合条件315例进行MRI与CTM对比分析,其中297例行常规锁骨上探查臂丛神经根.结果 315例有疑患侧神经根1575个,MRI诊断椎管内神经根损伤的灵敏度为84.35％,特异度为95.79％,总符率为89.13％.部分型中单纯前根或后根完全撕脱73个,前根和/或后根部分撕脱的有63个神经根,MRI仅诊断出108个,符合率为79.41％,CTM显示神经根断裂型损伤43个,MRI诊断31个,符合率为72.09％.结论 MRI-Balance SSFP序列作为无创性检查在臂丛神经根损伤的患者中起到重要作用并可作为首选筛查诊断方法.     

64层CT脊髓造影多平面重组对颈神经根损伤的诊断价值

目的前瞻性研究64层CT的脊髓造影（CTM）多平面重组（MPR）在颈神经根损伤中的诊断价值及其替代直接扫描横断面图像及常规X线脊髓造影的可能性。方法对26例临床诊断为颈神经损伤患者进行X线脊髓造影和64层CT各向同性扫描，然后进行MPR成像，并进行MPR多方向调整，使病变显示于冠状、矢状和横断面上。其中26例（54个神经根）进行了手术探查并有术后诊断结果，就其冠状、矢状断面MPR图像、直接扫描CT横断面图像、脊髓造影平片对病变的诊断符合率进行对比，并比较横断面MPR与直接扫描横断面CT的图像数量。结果以患侧蛛网膜下腔内颈神经根前后支走行区和神经孔处充盈缺损消失，连续性无神经根显示为直接征象，CTM发现神经根损伤31个。间接征象表现为：（1）创伤性脊膜膨出：椎管内患侧硬膜囊膨大、变形，呈柱形高密度影，并可沿椎间孔向外延伸，形成神经根鞘膜囊肿，与蛛网膜下腔间有低密度的细线状分隔，在撕裂水平可见29个膨出。（2）蛛网膜囊肿：硬膜囊一侧膨大变形，呈囊样扩张，病变未经椎间孔向外延伸，与蛛网膜下腔间有细线状分隔26个。（3）蛛网膜下腔不对称：一侧腔变窄，脊髓有不同程度的移位，多层面显示各神经根走行区未见连续性充盈缺损17个。64层CT多向调整的冠状面MPR对病变的诊断符合率为92，6％（50／54个），高于直接扫描CT横断图像（77.8％，42／54个）及平片（68．5％，37／54个），3种影像方法与术后诊断结果进行Kappa一致性检验比较，X线平片、CTM横断面和曲面冠状MPR的Kappa值分别为0．686、0．772、0．920，P值均〈0．05。可见曲面冠状MPR与手术诊断结果高度一致。而图像数量明显少于横断面CT（MPR50幅图像，横断面CT400幅图像）。结论多向调整的冠状面MPR解决了多层CT图像数量庞大的问题，该方法省时、易行，可直观清晰显示颈神经根损伤范围，提高了诊断符合率。     

腰椎间盘突出症的X线诊断(附115例X线平片、造影及手术对照分析)

本文介绍了115例(125个病变椎间盘)腰椎间盘突出症患者的平片及脊髓造影的X线征象,并与手术结果对照分析,诊断准确率为91.2％。椎体后缘唇样骨质增生和骨内软骨结节、椎间隙的前窄后宽等征象对椎间盘突出有定位诊断价值。腰骶椎脊髓造影显示硬膜囊和神经根的压迫征象,对于腰椎间盘突出的定位诊断及鉴别诊断均有重要意义。     

Myelography for nerve root avulsion in birth palsy

Myelography and CT myelography (CTM) were reviewed in 18 cases of birth palsy with clinically suspected avulsion injury. Root-somatosensory evoked potential (root-SEP) was also reviewed for myelographic evaluation of the nerve root avulsion in birth palsy. Root-SEP is not induced in case of avulsed nerve roots, but is induced in case of both normal and incompletely avulsed roots. Myelography demonstrated 58 abnormal nerve roots in 18 cases (19 limbs); 45 (78%) complete and 13 (22%) incomplete nerve root avulsions. Each of complete and incomplete avulsions was defined as total absence and partial presence of rootlets on myelography, respectively. Traumatic meningoceles were detected at 46 roots (79%) on myelography and/or CTM; 35 roots on myelography and 45 roots on CTM. CTM could not detect only a very small meningocele at one root. At 11 roots CTM was superior to myelography in delineating a meningocele because CTM is sensitive to a poorly enhanced meningocele. CTM, however, could not diagnose nerve root avulsions so accurately as myelography, since myelography detected 12 (7 completely and 5 incompletely) avulsed roots without meningocele, whereas CTM could not delineate the nerve roots clearly. Thus, myelography is indispensable to evaluate nerve root avulsions without meningocele. Root-SEP was examined in 9 patients who underwent brachial plexus exploration. SEP was negative at 22/25 roots with complete avulsion and was positive at 7/7 roots with myelographically incomplete avulsion, regardless of presence or absence of any traumatic meningocele.(ABSTRACT TRUNCATED AT 250 WORDS)     

CSF flow jet: novel CT myelogram finding of CSF leak through dural tear in traumatic pseudomeningocele

Determining the exact location of dural violation after traumatic pre-ganglionic (avulsion) injury of the brachial plexus with associated progressively enlarging pseudomeningocele is critical for treatment, but current imaging by MR and CT myelogram remains inadequate as there are often only indirect imaging features. We present a case of a 25-year-old man with history of motorcycle accident and left brachial plexus injury, who was found to have an extensive anterior epidural CSF collection, resulting in the contralateral neurologic deficit. Surgical treatment relies upon the identification of the site of the dural violation. On dynamic CT myelogram images, a thin hyperdense line of contrast was seen, representing “CSF flow jet” extravasating into the pseudomeningocele. Subsequent laminectomy and foraminotomy revealed a left avulsed nerve root and a dural tear at the site localized on the CT myelogram. To our knowledge, this is the first case of using dynamic CT myelography to visualize “CSF flow jet,” revealing the exact location of dural violation resulting in the expanding pseudomeningocele, providing crucial information for perioperative planning.     

Predicting High-Flow Spinal CSF Leaks in Spontaneous Intracranial Hypotension Using a Spinal MRI-Based Algorithm: Have Repeat CT Myelograms Been Reduced?

BACKGROUND AND PURPOSE:We adopted an imaging algorithm in 2011 in which extradural fluid on spinal MR imaging directs dynamic CT myelography. We assessed algorithm compliance and its effectiveness in reducing repeat or unnecessary dynamic CT myelograms.MATERIALS AND METHODS:CT myelograms for CSF leaks from January 2011 to September 2014 were reviewed. Patients with iatrogenic leaks, traumatic brachial plexus injuries, or prior CT myelography within 2 years were excluded. Completion and results of spinal MR imaging, CT myelographic technique, and the need for repeat CT myelography or unnecessary dynamic CT myelograms were recorded.RESULTS:The algorithm was followed in 102 (79%) of 129 patients. No extradural fluid was detected in 75 (74%), of whom 70 (93%) had no leak, 4 (5%) had a slow leak, and 1 (1%) had a fast leak. Extradural fluid was detected in 27 (26%): 24 (89%) fast leaks, 1 (4%) slow leak, and 2 (7%) with no leaks. When the algorithm was followed, 1 (1%) required repeat CT myelography and 3 (3%) had unnecessary dynamic CT myelograms. The algorithm was breached in 27 (21%) cases, including no pre-CT myelogram MR imaging in 11 (41%), performing conventional CT myelography when extradural fluid was present in 13 (48%), and performing dynamic CT myelography when extradural fluid was absent in 3 (11%). Algorithm breaches resulted in 4 (15%) repeat CT myelograms and 3 (12%) unnecessary dynamic CT myelograms, both higher than with algorithm compliance.CONCLUSIONS:Using spinal MR imaging to direct CT myelography resulted in significant reduction in repeat CT myelograms to localize fast leaks with minimal unnecessary dynamic CT myelograms.

Extradural fluid on spinal MR imaging has been reported to predict fast spinal CSF leaks for which the leak site may not be localized on conventional CT myelograms (CTMs).¹ We adopted an imaging algorithm in January 2011 for the evaluation of patients with clinical suspicion of spinal CSF leak. The first step of this algorithm is to perform MR imaging of the entire spinal canal, and the results of the MR imaging are then used to guide the type of CTM initially performed. Specifically, if extradural fluid is present on MR imaging, dynamic CTM is performed. Our current technique used for dynamic CTM has been previously reported.² If extradural fluid is not present, conventional CTM is performed.The goal of adopting this algorithm was to attempt to reduce the number of repeat dynamic CTMs for leak localization in patients with fast spinal CSF leaks who initially underwent conventional CTM with the leak identified but not localizable. Averaged over the previous 8 years, repeat dynamic CTM for leak localization was performed in 21% of patients at our institution.¹ Reducing repeat CTM is desirable for several reasons, including radiation reduction, cost savings, and fewer invasive procedures.The purpose of this study was to retrospectively evaluate our compliance with the algorithm and determine its effectiveness in reducing repeat dynamic CTM performed for leak localization.     

Three-dimensional MR myelography of traumatic injuries of the brachial plexus.

PURPOSETo determine the diagnostic accuracy of three-dimensional MR myelography in the evaluation of traumatic injuries of the brachial plexus.METHODSTwenty patients with clinical and electromyographic evidence of traumatic brachial plexopathy were examined with three-dimensional MR myelography, conventional cervical myelography, and CT myelography 1 to 9 months after trauma. Three-dimensional MR myelography was performed on a 1.5-T MR unit with a constructive interference in steady state (CISS) technique. For each patient, maximum intensity myelographic projections and multiplanar reconstruction reformatted 1-mm axial sections were obtained from the same 3-D data set. Three-dimensional MR myelographic findings were compared with findings at cervical myelography and CT myelography. Surgical findings were available for comparison in 13 patients.RESULTSThree-dimensional MR myelography enabled detection of meningoceles with avulsed or intact nerve roots, partial or complete radicular avulsions without disruption of the thecal sac, dural sleeve abnormalities, and dural scars. Assuming cervical myelography and CT myelography as the standards of reference, 3-D MR myelography showed 89% sensitivity, 95% specificity, and 92% diagnostic accuracy in the evaluation of nerve root integrity.CONCLUSIONThree-dimensional MR myelography can show the majority of traumatic lesions that involve the proximal portion of the brachial plexus in a single rapid examination. On the basis of our findings, we propose this technique as a screening examination for patients with traumatic brachial plexus palsy.     

The Diagnostic Value of CT Myelography,MR Myelography,and Both in Neonatal Brachial Plexus Palsy

BACKGROUND AND PURPOSE:Although most infants with brachial plexus palsy recover function spontaneously, approximately 10–30% benefit from surgical treatment. Pre-operative screening for nerve root avulsions is helpful in planning reconstruction. Our aim was to compare the diagnostic value of CT myelography, MR myelography, and both against a surgical criterion standard for detection of complete nerve root avulsions in birth brachial plexus palsy.MATERIALS AND METHODS:Nineteen patients who underwent a preoperative CT and/or MR myelography and subsequent brachial plexus exploration were included. Imaging studies were analyzed for the presence of abnormalities potentially predictive of nerve root avulsion. Findings of nerve root avulsion on surgical exploration were used as the criterion standard to assess the predictive value of imaging findings.RESULTS:Ninety-five root levels were examined. When the presence of any pseudomeningocele was used as a predictor, the sensitivity was 0.73 for CT and 0.68 for MR imaging and the specificity was 0.96 for CT and 0.97 for MR imaging. When presence of pseudomeningocele with absent rootlets was used as the predictor, the sensitivity was 0.68 for CT and 0.68 for MR imaging and the specificity was 0.96 for CT and 0.97 for MR imaging. The use of both CT and MR imaging did not increase diagnostic accuracy. Rootlet findings in the absence of pseudomeningocele were not helpful in predicting complete nerve root avulsion.CONCLUSIONS:Findings of CT and MR myelography were highly correlated. Given the advantages of MR myelography, it is now the single technique for preoperative evaluation of nerve root avulsion at our institution.

Brachial plexus palsy occurs in approximately 1 in 1000 neonates.^1,2 Downward traction on the shoulder girdle produces stereotyped patterns of plexus injury.³ Nerve lesions occur first at higher levels, with more severe traction resulting in progressive inferior extension.^3,4 More superior nerve injury is typically extraforaminal, at the level of the superior trunks, because a well-developed investing fascia protects the upper nerve roots from proximal traction. In contrast, inferior lesions are more often intraforaminal, manifesting as either partial or complete avulsion of the nerve root.⁴Clinical manifestations and spontaneous recovery depend on the extent, location, and type of nerve lesions. The clinical presentation can generally be grouped into 1 of 4 patterns outlined by Narakas⁵: Type I involves C5 and C6 deficits (Erb-Duchenne type) with loss of shoulder abduction, shoulder external rotation, elbow flexion, and forearm supination. Type II involves C5 to C7/C8 deficits, resulting in a “waiter''s tip” posture from additional loss of wrist extension. Type III involves C5 to C8/T1 deficits, resulting in an arm that is generally paralyzed. Type IV involves C5 to T1 and the sympathetic chain, resulting in a flail arm with Horner syndrome. Upward traction on the brachial plexus can result in isolated lower plexus deficits that manifest as paralysis of the hand only.^6,7 This pattern is known as Klumpke palsy.The decision to proceed with surgical exploration and reconstruction is based on the clinical presentation and progression. While 70%–90% of infants are treated with therapy alone, 10%–30% have indications for surgical treatment.^8–11 Nerve injuries distal to the intervertebral foramen can be reconstructed by using nerve grafts, whereas intraforaminal nerve root avulsions require nerve transfer. While both partial and complete nerve root avulsions are described,^12,13 there is no clear consensus on the surgical approach to partial nerve root avulsions. Preoperative imaging capable of accurately identifying complete nerve root avulsions and distinguishing them from extraforaminal nerve injuries is, therefore, critical for optimal surgical planning.The current standard for preoperative assessment of nerve root avulsions in infants is CT myelography.^12,14–19 A pseudomeningocele is suggestive of nerve root avulsion, and the additional finding of absent rootlets traversing the pseudomeningocele greatly increases the specificity of this finding.¹⁴ CT myelography requires a lumbar puncture for injection of intrathecal contrast, with attendant risks of infection and seizure.^20–22 Recent studies have also raised concern for malignancy with early exposure of children to radiation.^23,24 MR myelography can be performed without injection of contrast and is a promising alternative.^17,25 However, the performance of MR myelography for predicting nerve root avulsion is not yet established²⁶ in neonatal brachial plexus injury, and the diagnostic value of MR myelography has yet to be compared with CT myelography in this setting.The purpose of this study was to determine the predictive value of CT myelography, MR myelography, and both CT and MR myelography for detecting complete nerve root avulsions in neonatal brachial plexus palsy, by using a surgical criterion standard.     

High-Resolution MRI Evaluation of Neonatal Brachial Plexus Palsy: A Promising Alternative to Traditional CT Myelography

BACKGROUND AND PURPOSE:Despite recent improvements in perinatal care, the incidence of neonatal brachial plexus palsy remains relatively common. CT myelography is currently considered to be the optimal imaging technique for evaluating nerve root integrity. Recent improvements in MR imaging techniques have made it an attractive alternative to evaluate nerve root avulsions (preganglionic injuries). We aim to demonstrate utility of MR imaging in the evaluation of normal and avulsed spinal nerve roots.MATERIALS AND METHODS:All study patients with clinically diagnosed neonatal brachial plexus palsy underwent MR imaging by use of a high-resolution, heavily T2-weighted (driven equilibrium) sequence. MR imaging findings were reviewed for presence of nerve root avulsion from C5–T1 and for presence of pseudomeningocele. The intraoperative findings were reviewed and compared with the preoperative MR imaging findings.RESULTS:Thirteen patients (9 male, 4 female) underwent MR imaging; 6 patients underwent nerve reconstruction surgery, during which a total of 19 nerve roots were evaluated. Eight avulsions were noted at surgery and in the remainder, the nerve injury was more distal (rupture/postganglionic injury). Six of the 8 nerve root avulsions identified at surgery were at C5–6 level, whereas 1 nerve root avulsion was identified at C7 and C8 levels, respectively. The overall sensitivity and specificity of MR imaging for nerve root avulsions was 75% and 82%, respectively.CONCLUSIONS:Our preliminary results demonstrate that high-resolution MR imaging offers an excellent alternative to CT myelography for the evaluation of neonatal brachial plexus palsy with similar sensitivity compared with CT myelography.

Neonatal brachial plexus palsy (NBPP) results from insult to the brachial plexus during the perinatal period.¹ NBPP can result when the upper shoulder of the infant becomes blocked by the pubic symphysis of the mother.^2,3 Nerve injury can occur anywhere along the brachial plexus but generally occurs in the supraclavicular brachial plexus at the nerve roots/trunks levels, resulting in varied neurologic deficits. Damage to the nerve roots arising from the ventral aspect of the spinal cord results in motor function disability. The most common lesions occur within the C5 and C6 spinal nerves (80% of patients), with a smaller group of patients having more extensive lesions ranging from C5–C7 and from C5–T1 (pan-plexopathy).^1,3 Collectively, the clinical presentation resulting from these lesions is referred to as NBPP.NBPP occurs with an incidence of up to 3 per 1000 live births.¹ The most severe forms of injury result from complete axonal disruption (neurotmesis or severe axonotmesis), either at the level of the proximal nerve roots or trunks of the brachial plexus (ruptures, postganglionic injury), or when 1 or more of the spinal nerves of the brachial plexus are torn out of the spinal cord (root avulsion, preganglionic injury).⁴ In these cases, the likelihood of spontaneous recovery is low and surgical intervention is generally thought to be reasonable.⁵ Less severe injuries such as simple stretching of the nerves (neurapraxia) or rupture of a few axons (mild axonotmesis) can result in spontaneous functional recovery³ (Fig 1). The clinical treatment of patients with NBPP can be difficult and depends on the specific type of lesion involved. Early on, it is often difficult to characterize the lesion type because patients may clinically present with similar apparent deficiencies regardless of the levels involved. This presents a diagnostic and management dilemma because patients with neurapraxia/mild axonotmesis will demonstrate spontaneous recovery over time, whereas the effectiveness of surgical intervention for neurotmesis or nerve root avulsion decreases with time. The typical practice at this time is to allow the patient a 3-month period in which to exhibit spontaneous recovery.^4,5 If recovery does not occur or is incomplete, further evaluation is recommended to determine the extent of injury. Perhaps there is a role for imaging earlier after birth because patients with minor injuries could be given a more favorable prognosis without the waiting period, at the admitted increased medical costs. However, it is possible that early imaging can save medical costs downstream by identifying patients who do not need more extensive follow-up and evaluation in the future.Open in a separate windowFig 1.Schematic diagram showing different patterns of injuries affecting the nerve, including neuropraxia (A), mild axonotmesis (B), and neurotmesis (C).Although direct surgical exploration may be considered the reference standard for lesion characterization, it carries significant morbidity and would require laminectomy to observe the intradural nerve roots. For this reason, CT myelography (CTM) and electrodiagnostic studies have been used as less invasive techniques and comprise the standard preoperative assessment for establishing preganglionic nerve root avulsion and postganglionic nerve ruptures in neonatal, pediatric, and adult populations.^4,6 CTM is most useful for detection of root avulsions (72% sensitivity), whereas electrodiagnostic studies are best at detecting postganglionic nerve ruptures, especially in the upper plexus (93% sensitivity).⁶ These 2 tests are generally used in combination with one another to provide the neurosurgeon with supplemental preoperative information.⁶Although CTM is currently the most widely used imaging method for evaluating nerve root avulsion, there are drawbacks. It requires an invasive lumbar puncture, instillation of iodinated contrast into the thecal sac, and the use of radiation, all of which carry unfavorable risks, particularly within the infant and pediatric populations. Nevertheless, CTM continues to be recommended in every preoperative assessment for NBPP at many specialty centers.^4,6 Recent improvements in MR imaging techniques have made MR imaging an attractive alternative to conventional CT. MR imaging is noninvasive, does not require the use of intrathecal contrast, and does not use ionizing radiation. This technique, if effective at diagnosing nerve root avulsion, can emerge as an alternative technique to CTM in the pediatric population. To date, however, there are only a few reports contained in the literature examining the utility of MR imaging for nerve root avulsions and none looking specifically at NBPP.^7–11 The reports contain scant imaging examples of nerve root avulsion, and many of the images are not convincingly diagnostic.¹² Most of the reports focus on the use of a heavily T2-weighted 3D sequence, referred to under various names on the basis of the specific manufacturer, such as 3D CISS (constructive interference in steady state), 3D True-FISP (fast imaging with steady-state precession), FIESTA (fast imaging employing steady-state acquisition), and DRIVE (driven equilibrium) sequences.⁷ The end goal of these sequences is the same: to create a sequence with very high CSF-to-tissue contrast with elimination of pulsation artifact, to optimally visualize the exiting cervicothoracic nerve roots.¹³ Until now, however, there are no studies that unequivocally and consistently demonstrate high-quality images of nerve root avulsion. Some propose that it lacks the requisite spatial resolution to provide the neurosurgeon with necessary diagnostic information,¹⁴ though more recent advances in high-resolution 3T MR challenge this proposition.¹⁵ Our aim was to use high-resolution MR imaging in evaluation of ventral nerve root avulsions in NBPP and to demonstrate that it is an excellent noninvasive and nonirradiating alternative to CTM.     

Role of FIESTA combined with conventional MRI in the evaluation of traumatic brachial plexus roots injury

Purpose

Purpose was to evaluate the role of Fast imaging employing steady-state acquisition (FIESTA) together with conventional MR sequences in the evaluation of traumatic brachial plexus roots injury compared to post contrast MR and Spin Echo MR myelographic studies.

Patients and methods

In this prospective study, 16 patients with a mean age of 17.9 y who presented with traumatic brachial plexus roots injury in motor cycle and car accidents were studied with FIESTA, conventional MR, post contrast MR and MR myelography sequences. Imaging findings included: pseudo-meningocele/hemorrhage near the nerve root exit, failure of visualization of the nerve root (dorsal, ventral or both), retracted avulsed nerve root ends, spinal cord edema, and para spinal muscles edema and hemorrhage. Diagnostic accuracy was calculated for each MR sequence. Imaging findings were compared with the gold standard operative findings.

Results

FIESTA combined with conventional MR depicted pseudomeningoceles, non visualized nerve roots, cord displacement, and para spinal muscles abnormalities in 15 patients (93.8%), cord edema in four patients (25%). Pre and post contrast MR detected pseudomeningoceles and non visualized nerve roots in 13 patients (81.3%) while Spin Echo myelography detected pseudomeningoceles and non visualized nerve roots in 14 patients (87.5%). FIESTA combined with conventional MR showed the highest diagnostic accuracy (93.8%) compared to pre and post MR (81.3%) and Spin Echo myelography (87.5%).

Conclusion

It is crucial to differentiate between preganglionic and postganglionic injuries for optimal treatment planning in patients with BPI. Conventional MR imaging yielded suboptimal information regarding the fine details of nerve roots’ injury. MR myelography showed some artifacts that decreased overall diagnostic accuracy, FIESTA combined with conventional MR depicted nerve segments in greater detail and provided important information about the relationship of the nerves to nearby structures, it provided high contrast resolution between cerebrospinal fluid and solid structures, allowing the reconstruction of elegant multi-planar images that highlight the injured nerves. Contrast study is recommended in mild trauma cases with normal morphological study.     

Brachial plexus traumatic root injury in adults: Role of different non contrast MRI sequences in pre-operative assessment

Aim of the work

To evaluate the role of fast imaging employing steady-state acquisition (FIESTA) together with conventional MRI and MR myelography (MRM) sequences in evaluation of brachial plexus traumatic roots injury in adults in correlation with surgical outcome.