Tuberous sclerosis: Evaluation of intracraneal lesions Poster No: C-3394 Congress: ECR 2010 Type: Educational Exhibit Topic: Neuro Authors: J R Docampo, M Cabrini, C Morales, C Bruno; Buenos Aires/ AR Keywords: cortical tubers, subependymal hamartomas, giant-cell astrocytoma DOI: 101594/ecr2010/C-3394 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 wwwmyesrorg Page 1 of 25
Learning objectives To show our imaging findings of intracranial lesions found in patients with Tuberous Sclerosis (TS) who were evaluated with MRI and/or CT To show their typical imaging features Background Tuberous sclerosis is a neurocutaneous disease characterized by the clinical triad of mental retardation, seizures and skin lesions Characteristic brain lesions can be diagnosed with MRI and CT Twenty-seven patients with a clinical diagnosis of TS (20 MRI images, 2 CT scans, and 5 with both methods) were examined (age range, 2 months to 28 years) There were 15 male and 12 female patients A 05 and 15 Tesla MRI Scanners and axial/helical CT scanners were used One patient was evaluated with spectroscopy and diffusion Monovoxel magnetic resonance spectroscopy was performed applying PRESS sequences, echo times of 25ms and 144ms The protocol used on MRI consisted in SE axial T1- and T2-weighted sequences, FLAIR and GRE sequences (TK: 7mm / GAP: 05mm) In studies requested with paramagnetic contrast agents, T1-FSE sequences were added in the 3 post-contrast planes Sixteen patients required paramagnetic contrast agents, with an administered dose of 02ml/kg body weight Twenty-three patients underwent general anesthesia for the performance of the study Imaging findings OR Procedure details In 26 cases, the examinations showed subependymal hamartomas, cortical tubers in 26 patients, white matter lesions in 3 cases, sulcal expansion in 3 patients, 2 parenchymal cysts, giant-cell astrocytoma in 1 case, ventricular expansion in 1 patient and one patient with a space-occupying lesion in posterior fossa Page 2 of 25
Fig: Table 1: Patients with tuberous sclerosis SH: subependymal hamartomas; GCA: giant cell astrocytoma; CoT: cortical tubers; PC: parenchymatous cysts; WML: white matter lesions; CL: cerebellous; VSD: ventricular system dilation; CSW: widened convexity sulci References: J R Docampo; Neuro MR, Fundacion Cientifica del Sur, Buenos Aires, ARGENTINA Page 3 of 25
Fig: Graph 1: Frequency of intracranial findings in patients with tuberous sclerosis References: J R Docampo; Neuro MR, Fundacion Cientifica del Sur, Buenos Aires, ARGENTINA Subependymal nodules These are hamartomas which histologically contain giant cells with features of neurons and astrocytes In our case history, subependymal nodules were the most frequent finding, identified in 26 patients The imaging appearance of subependymal hamartomas on CT scan and MRI varies with age of patient (1) On CT scan, subependymal hamartomas are isodense with respect to the white matter; in older patients they may become calcified (Picture 1 on page 8) and may be identified as hyperdense (2) Nodules calcify progressively during the first two decades of life; a calcified nodule (1) is hardly found in patients under 1 year of age We found calcified subependymal hamartomas in 4 patients under 1 year of age (Picture 2 on page 8) On MRI, subependymal nodules in newborns are slightly hyperintense on T1 with respect to the white matter (Picture 3 on page 9) and of heterogeneous intensity on T2; this is due to the hypomyelination of the white matter As myelination occurs, nodules become Page 4 of 25
isointense on T1 and T2 with respect to it (Picture 4 on page 11) If they calcify, they are markedly hypointense on gradient echo sequences (2) Post-contrast paramagnetic identification varies, absence of enhancement being more (2) frequent In our study, 12 of the 16 patients evaluated with paramagnetic contrast agents showed enhancement of subependymal hamartomas (Pictures 5 on page 11 and 6 on page 12) Subependymal astrocytomas These are histologically benign tumors formed by giant cells which present features of astrocytes and neurons In our case history, a subependymal astrocytoma was identified in 1 patient Their typical location is near Monro's holes Subependymal astrocytomas may cause obstructive hydrocephaly (2) Occurrence age is between 8 and 18 years Their diagnosis and follow-up are important, because if they grow and produce obstructive hydrocephaly, they may require neurosurgery On CT and MRI, subependymal astrocytomas are bigger than subependymal hamartomas; they are usually enhanced by paramagnetic contrast agents (Picture (2) 7 on page 12), they may calcify and present bleeding Differential diagnosis with subependymal hamartomas is determined by the "evolutional control", since subependymal astrocytomas grow whereas hamartomas do not (1) Cortical tubers These are benign hamartomatous lesions, which rarely become malignant They may be single or multiple In our study, 26 patients presented with cortical tubers The frontal lobes are the most frequent site, followed by the parietal, occipital and temporal lobes in decreasing order (2) Histologically they are composed of bizarre giant cells, dense fibrillar gliosis and disorganized myelin bands On CT scan, in newborns and unweaned babies, hamartomas are hyperdense (Picture 8 on page 13) and the sulci where they are located are usually widened Throughout Page 5 of 25
the years they become hypodense (Picture 9 on page 13) calcify (1) Cortical tubers may also On MRI, at the beginning of life cortical tubers are slightly hyperintense on T1-weighted sequences with respect to the white matter, and hypointense on T2 As the encephalus myelinates, tubers become iso-hypointense on T1 and hyperintense on T2 (Picture 10 on page 14) FLAIR sequence has an enhanced sensitivity in the diagnosis of cortical tubers in children as well as in adults (Picture 11 on page 15) Cortical tubers are identified as hyperintense images of diffuse limits at the site where the lesions are located (1) When tubers calcify, they are identified as hypointense on gradient echo sequences and slightly hyperintense on T1 (2) Some authors divide cortical tubers into 2 types: "gyral core" and "sulcal island" Gyral core is a hyperintense lesion on T2 and hypointense on T1 (Picture 12 on page 15) which is located in the center of an expanded (widened) circumvolution, the cortex of which is of normal thickness (3, 4) Sulcal island is a lesion where the subcortical white matter is hyperintense on T2 and iso-hypointense on T1 (Picture 13 on page 16), and involves two adjacent circumvolutions; the cortex is of conserved thickness (3, 4) Parenchymatous cysts These lesions are usually located at any site, although they are mostly found in the periventricular white matter (2) In our study, 2 patients were reported with intraparenchymatous cysts On CT scann, they are identified as round hypodense images On MRI, they are hyperintense images on T2, and hypointense on T1 and FLAIR (Picture 14 on page 17) White matter lesions These lesions are formed by giant cells These cells are 5 to 10 times larger than astrocytes Giant cells have features of neurons and of glial cells (2) In our study, they have been reported in 3 patients Page 6 of 25
These lesions present different appearances; they can be linear, cuneiform, or form a conglomerate The usual appearance is the linear pattern, from the cortex to the periventricular region (2) On CT scan, they are usually slightly hypodense, and they may also calcify (Picture 15 on page 18) On MRI, they are identified as hyperintense images on T2 They are rarely enhanced with postcontrast agents (2) Cerebellous lesions (1) These lesions are identical to cortical tubers They are present in 10% of patients In our study, we only found one patient with a tuber located at the bottom of the fourth ventricle, calcified (hypointense on gradient echo), which is faintly enhanced with paramagnetic postcontrast agents (Picture 16 on page 19) They are difficult to diagnose with CT scan due to the great number of artifacts that the method has in the posterior fossa; therefore, the study of choice to identify them is MRI Magnetic resonance diffusion and spectroscopy One patient underwent diffusion-weighted MR imaging, which confirmed that subependymal hamartomas and cortical tubers are isointense with respect to the white (5) matter on DWI In the apparent diffusion coefficient (ADC), subependymal hamartomas are discreetly hypointense and cortical tubers are slightly hyperintense (Picture 17 on page 20) In the short echo time spectroscopy, a decrease in N-acetylaspartate (NAA) was confirmed, and a slight increase in myoinositol at the level of the cortical tubers (Picture 18 on page 21and 19 on page 22) On the long echo time PRESS sequence, a slight (6) increase in NAA was confirmed Subependymal hamartomas cannot be evaluated by spectroscopy due to their periventricular location, since the cephaloraquideal liquid alters the spectrum Page 7 of 25
Images for this section: Fig 1: CT scan of a one-year-old male patient, where hyperdense nodullary images are identified, calcified, of subependymal location, compatible with subependymal hamartomas and cortical hypodense images compatible with adolescents Page 8 of 25
Fig 2: CT scan of a 2-month-old male patient who had seizures in his first month of life Hyperdense subependymal nodules are shown (arrows) slightly calcified (subependymal hamartomas) Page 9 of 25
Fig 3: MRI on axial T1-weighted sequences of a 5-year-old male patient, who presents with hyperintense subependymal nodules located in both lateral ventricles (arrows) Page 10 of 25
Fig 4: MRI on axial T1-weighted sequences (A) and axial T2 (B) of a female patient, who presents with isointense subependymal hamartomas on T1 and T2 with respect to the white matter (arrows) Page 11 of 25
Fig 5: MRI on axial T1 without contrast agent (A) and with gadolinium (B) of a 2-yearold male patient, who presents with a subependymal nodule, enhanced with postcontrast agents (arrow) Fig 6: A subependymal nodule of significant size is identified, located on the wall of the left lateral ventricle (arrows), hypointense on T2 (A), isointense on T1 (B) and which is significantly enhanced with paramagnetic postcontrast agents (C), compatible with subependymal hamartoma Page 12 of 25
Fig 7: On this MRI of a 7-year-old female patient, an intraventricular, ovoid, voluminous mass is observed, which produces hydrocephaly as it occludes Monro's holes; this mass is hyperintense on T2 (A), isointense on T1 (B) and is significantly enhanced after the administration of paramagnetic contrast agents (C) This image is compatible with a subependymal giant cell astrocytoma Fig 8: CT scan of a 2-month-old male patient, where cortical hyperdense images are identified, compatible with cortical tubers (arrows) Page 13 of 25
Fig 9: CT scan of a 1-year-old male patient, which shows cortical hypodense images, compatible with cortical tubers (arrows) Page 14 of 25
Fig 10: MRI of a 2-year-old female patient, who presents with multiple hyperintense images on T2 (A), and hypointense on T1 (B), compatible with cortical tubers (arrows) Fig 11: MRI of a 2-year-old male patient which shows, on FLAIR sequence, multiple hyperintense cortical images (arrows) Page 15 of 25
Fig 12: MRI of a 7-year-old female patient On the coronal T2-weighted sequence a hyperintense lesion is shown, located in the center of an expanded circumvolution (arrows), labeled "gyral core" Page 16 of 25
Fig 13: MRI of a 2-year-old male patient A lesion in the subcortical white matter is identified, hyperintense on axial T2-weighted sequence, which involves two adjacent circumvolutions (arrows), labeled "sulcal island" Page 17 of 25
Fig 14: MRI of an 8-year-old female patient, which presents a hyperintense image on T2 (A) and hypointense on T1 and FLAIR (B and C), round, adjacent to the occipital prolongation of the right lateral ventricle (arrows)"parenchymatous cysts" Page 18 of 25
Fig 15: CT scan and MRI of a 2-year-old male patient who presents with a lesion in the white matter corresponding to the left external capsule (arrows), calcified, identified as hyperdense on CT scan (A), hypointense on T2 (B) and hyperintense on T1 (C) Page 19 of 25
Fig 16: MRI of a 16-year-old male patient who presents with a hypointense image on gradient-echo at the bottom of the fourth ventricle (A), which is enhanced with paramagnetic contrast agents (B), compatible with cerebellous calcified hamartoma (arrows) Page 20 of 25
Fig 17: Axial T2-sequence (A) of a 1-year-old male patient, who presents with subependymal hamartomas in both lateral ventricules (white arrows), and cortical tubers (circle) In the diffusion, in DWI (B) subependymal hamartomas are isointense with respect to the white matter (arrows) In ADC (C), subependymal hamartomas are slightly hypointense with respect to the white matter (arrows) and the cortical tubers are hyperintense (circle) Page 21 of 25
Fig 18: continued: The same patient underwent a spectroscopy applying monovoxel technique with PRESS sequences, echo time 25ms corresponds to the normal side Page 22 of 25
Fig 19: continued Spectroscopy applying monovoxel technique with PRESS sequences, echo time 25ms Corresponds to the evaluation of the cortical tuber, where a decrease in the NAA peak is observed, and an increase in the myoinositol peak Page 23 of 25
Conclusion In our study, subependymal hamartomas were the most frequent intracranial lesion (imaging feature) found in 26 patients with clinical diagnosis of TS, followed by cortical tubers in 26 cases Giant-cell astrocytoma was found in 1 case, and was associated to ventricular expansion Spectroscopy showed a decrease in NAA Personal Information Dr Docampo Jorge Neurorradiologo Fundación Cientifica del Sur (Lomas de Zamora Bs As Argentina) Jefe de servicio de resonancia magnética del HIGA Pedro Fiorito Bs As Argentina email: docampojorge@hotmailcom References (1) Barkovich AJ Facomatosis En: Barkovich AJ Neuroimagenología pediátrica Madrid: Marbán 2001; 6:417-429 (2) Hart B, Depper M, Clericuzio C Síndromes neurocutáneos En: Orrison WW, ed Neurorradiología Madrid: Harcourt 2001; 2(51):1732-1749 (3) Nixon JR, Houser OW, Gómez MR, Okazaki H Cerebral tuberous sclerosis: MR imaging Radiology 1989;170:869-873 Page 24 of 25
(4) Takanashi J, Sugita K, Fujii K, Niimi H MR evaluation of tuberous sclerosis: increased sensitivity with fluid-attenuated inversion recovery and relation to severity of seizures and mental retardation AJNR 1995;16:1923-1928 (5) Makki M, Chugani D, Janisse J, Chugani H Characteristics of abnormal diffusivity in normal-appearing white matter investigated with diffusion tensor MR imaging in tuberous sclerosis complex AJNR 2007; 28:1662-1667 (6) Mukonoweshuro W, Wilkinson I and Griffiths P Proton MR spectroscopy of cortical tubers in adults with tuberous sclerosis complex AJNR 2001; 22:1920-1925 Page 25 of 25