Spectrum of Magnetic Resonance Imaging findings in infective intra spinal complications of dermal sinus and associated inclusion cysts

Transcription

1 Spectrum of Magnetic Resonance Imaging findings in infective intra spinal complications of dermal sinus and associated inclusion cysts Poster No.: C-1443 Congress: ECR 2015 Type: Educational Exhibit Authors: P. Singh, V. Gupta, S. Vyas, A. Kumar, C. K. Ahuja, N. Khandelwal; Chandigarh/IN Keywords: Infection, Education, MR, Neuroradiology spine DOI: /ecr2015/C-1443 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 20

2 Learning objectives To familiarize 'radiologists-in-training' with various Magnetic Resonance Imaging (MRI) findings of infective intra spinal complications in pediatric patients with existing dermal sinus with or without inclusion cysts. Page 2 of 20

3 Background In young children presenting with clinical features of intra spinal infection, an underlying dermal sinus and associated epi/dermoid cyst may be overlooked by referring clinician or by reading radiologist due to atypical and confusing imaging findings on MRI [1]. The MRI findings of a complex intra spinal mass with bizarre enhancement pattern, meningitis, subdural / epidural abscesses and rarely spinal cord abscess may be difficult to interpret for the inexperienced radiologist [2,3]. Any delay in treatment can result in devastating neurological sequel and the condition needs prompt administration of antibiotics and surgery [4]. Familiarity with MRI findings may lead to prompt diagnosis and adequate treatment and prevent adverse neurological sequelae. Page 3 of 20

4 Findings and procedure details We retrospectively analyzed conventional and contrast enhanced MR images of 11 patients (age 1-14 years, males = 5, females = 6) done in our department on 1.5 T and 3 T MR units. T1 weighted spin echo, T2 weighted fast spin echo, fat suppressed contrast enhanced T1 spin echo sequences in sagittal, coronal and axial plane were evaluated. Diffusion weighted images using PSIF sequence were available in 2 patients. All patients presented with fever, flaccid or spastic paraplegia and bowel / bladder involvement in variable combination for varying duration. Meningeal signs were seen in 2 patients. Only in 6 patients a pre MRI mention of dermal cutaneous tract was available in MR requests. Dermal sinus was present in all patients as enhancing linear tracts in the back [Fig 1]. These were overlooked by clinician at initial examination in 5 patients and retrospectively detected after MRI. All lesions were in thoraco-lumbar region except one patient who had a cervico-dorsal dermal sinus and intraspinal partially intramedullary epidermoid [Fig 2]. The intra spinal extension of sinus was not clearly delineated in thoraco-lumbar lesions. The various other findings were as follows. The associated infected epidermoid cysts were seen as well defined enhancing cystic to complex irregular mass in conus-cauda equina region (n=5) with variable extensions [Fig 3, 4]. The lesions appeared hypo to iso intense on T1, hyper intense with mixed heterogeneous hypo intense areas on T2 and peripheral enhancement [Fig 5]. Two cysts were nearly intramedullary in location [Fig 2,3]. One cyst could be seen separate from conus in relation to filum lower down [Fig 6,7]. Rest of the lesions were inseparable but closely adherent to cord with featureless appearance of the thecal sac. The clumped roots and enhancing membranes made the outline of lesions indistinct in these cases. The cervico-thoracic lesion was clearly delineated [Fig 2]. Diffusion images using PSIF sequence were helpful in delineating two of the underlying cysts [Fig 3,7A]. Meningitis was seen as lepto-meningealand subarachnoidal enhancement in 6 patients [Fig 8]. Secondary edema / non suppurative myelitis (n=10) appeared as non enhancing ill defined high T2 signal change within a swollen spinal cord ranging from mild to widespread in extent [Fig 3B, 6]. In two patients the associated edema/ myelitis extended into lower brain stem [Fig 9,10]. Page 4 of 20

5 There were four spinal cord abscesses (n=4). All abscesses showed peripheral enhancement, a septated swollen appearance of spinal cord and central non enhancement of pus, variably extending into cervico-thoracic cord [Fig 9,10,11,12]. Epidural / para spinal soft tissue T2 high signal and enhancement was associated with infected dermal sinuses (n=8) [Fig 2,8]. In one case there were large para spinal and gluteal abscesses looking like tubercular pathology [Fig 13]. As demonstrated, in many cases the various MRI findings of infection overlapped and coexisted in the same patient due to communication between multiple anatomical compartments resulting from developmental defects. All patients were aggressively treated with immediate administration of antibiotics and underwent surgery within 1-2 weeks. The outcome was favorable in most patients except in two patients who had recurrent infection of incompletely removed cysts and variable persistent neurological deficit in patients with cord abscesses. Page 5 of 20

6 Images for this section: Fig. 1: Enhancing dermal sinus tract leading to a heterogenous signal infected spinal canal contents on T1 weighted (A), T2 weighted (B) and fat suppressed T1 enhanced axial sections (C). Page 6 of 20

7 Fig. 2: T1 post contrast (A) and T2 (B)sagittal images showing cervic0-dorsal epidermoid cyst with infected dermal sinus posteriorly extending below the lesion. Associated epidural inflammation is visible with subtle changes of myelitis in cervical cord in this patient with neurological deficit. Epidural enhancement on post contrast axial T1 image (C). Page 7 of 20

8 Fig. 3: Infected well defined thoraco-lumbar epidermoid is mostly imbedded within and inseparable from conus medullaris with adjacent cord edema seen from T11 to L2 level, appearing hypo intense on T1 (A), hyper intense on T2 (B) with rim enhancement(c). Dorsal sinus is visible at L5 level. Restricted diffusion seen on PSIF images(d). Page 8 of 20

9 Fig. 4: Infected epidermoid cyst with dermal sinus. Complex heterogeneous enhancing thoraco-lumbar mass inseparable from the conus and cauda equina roots(a- T2 image, B- T1 image and C- contrast enhanced T1 images). Page 9 of 20

10 Fig. 5: Heterogenous mixed intensity epidermoid at thoraco-lumbar junction on T2 [A], T1 [B] and showing irregular enhancement of cyst and arachnoidal adhesions [C]. Page 10 of 20

11 Fig. 6: Epidermoid cyst at L4 vertebral level separately seen from conus in relation to filum terminale appearing hyperintense on T2 [A] and hypointense on T1 [B]. The spinal cord edema/non suppurative myelitis visible in thoracic cord. Dermal sinus is visible at sacral level. Page 11 of 20

12 Fig. 7: Same lesion as in figure 6. PSIF diffusion image showing the cyst as bright lesion due to restricted diffusion (A) and the cyst showing peripheral contrast enhancement [B]. Page 12 of 20

13 Fig. 8: T2 [A,C]. T1 [B] and contrast enhanced [D] images showing dermal sinus with lepto-meningeal enhancement of infected subarachnoid space. Also visible is enhancement of dermal sinus and epidural space [D]. Page 13 of 20

14 Fig. 9: Extensive spinal cord abscess extending from lumbar to cervicothoracic cord. Secondary non suppurative edema involving cervical cord and brainstem on T2 images [A,B] and T1 images [C].Note featureless spinal contents. Page 14 of 20

15 Fig. 10: On contrast enhanced fat suppressed T1 images, same case showing extensive peripherally enhancing cord abscess in thoraco-lumbar cord and lack of enhancement in cervical and brainstem non suppurative oedematous component. Page 15 of 20

16 Fig. 11: [A] T2, [B] T1 and contrast enhanced [C,D]images. Extensive cord abscess secondary to infected dermal sinus and epidermoid cyst in lumbar spine. Note septated abscess expanding the cord and extending up to mid cervical region [D]. The cyst and conus are inseparable from each other. Dermal sinus is visible in A. Page 16 of 20

17 Fig. 12: Heterogeneous thoraco-lumbar abscess appearing iso to hypo intense on T2 [A], iso intense on T1 [B] and the enhancing abscess [C.D]. There is non enhancing non suppurative edema higher up in cord. Page 17 of 20

18 Fig. 13: Same patient as Fig 12 with para spinal inflammatory enhancement and large abscesses in right posterior paraspinal and gluteal regions. Initial impression was a tubercular abscess. Page 18 of 20

19 Conclusion When unusual MRI findings of intra spinal infection including cord abscess are encountered in pediatric patients with relevant clinical presentation, an index of suspicion for presence of dermal sinus wit or without associated inclusion cysts may be sought as a possible explanation and the source of infection. A familiarity with such imaging features helps in reaching the diagnosis and initiate prompt treatment to reduce morbidity. Page 19 of 20

20 References 1. Barkovich AJ, Edwards MS, Cogen PH. MR evaluation of spinal dermal sinus tracts in children. Am J of Neuroradiol 1991;12: Benzil DL, Epstein MH, Knuckey NW. Intramedullary epidermoid associated with an intramedullary spinal abscess secondary to a dermal sinus. Neurosurg 1992;30: Rogg JM, Benzil DL, Haas RL, Knuckey NW. Intramedullary abscess, an unusual manifestation of a dermal sinus. Am J of Neuroradiolol 1993;14: Bukhari EE, Alotibi FE. Fatal Streptococcus melleri meningitis complicating missed infected intramedullary dermoid cyst secondary to dermal sinus in a Saudi child. J Trop Pediatr 2013;59: Page 20 of 20