Radiologic diagnosis of cerebral venous thrombosis and its differential diagnosis

Transcription

1 Radiologic diagnosis of cerebral venous thrombosis and its differential diagnosis Poster No.: C-0628 Congress: ECR 2014 Type: Educational Exhibit Authors: A. M. Vargas Díaz, C. Fernández Rey, D. Garcia Casado, Y. Rodríguez Alvarez, D. A. Puentes Bejarano ; Segovia/ES, Oviedo/ES, 40002/ES, Madrid/ES Keywords: Education and training, Education, MR, CT, Neuroradiology brain, Emergency, Anatomy DOI: /ecr2014/C-0628 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 25

2 Learning objectives The pourpose of our educational exhibit is to: Review the anatomy of the cerebral venous system and the anatomic variations. Illustrate the radiologic findings of cerebral venous thrombosis (CVT) and its differential diagnosis, according to the current literature. Page 2 of 25

3 Background CVT is an uncommon but potentially fatal disease with an incidence of 4 cases per million in the general population. The most common predisposing factors include infection, trauma, tumors, dehydration, cuagulation disordes, pregnancy, and treatment with oral contraceptives. The clinical presentation can be variable and include headache, blurred vision, focal neurological deficits, papilledema, seizures and coma. The CVT involves most often the superior sagittal sinus, transverse sinus and the straight sinus. Multiple involvement is present in more than 90% of the cases. The pathophysiology is complex and its effects on the parenchyma can trigger cytotoxic and vasogenic edema or hemorrhage. CASE 1 78 years old male, ex-smoker, with history of surgery for an anal fistula, is transferred from another center for study of brain lesions seen on CT Fig. 1 on page 4, the patient had sudden onset of disorientation, slurred speech and memory loss. MRI study was performed showing signs of subacute CVT affecting the superior sagittal sinus (SSS) and right transverse sinus (ST) (hiperintensity on T1WI and T2WI, restricted diffusion and corresponding low signal on ADC map, in the left frontal lobe is observed vasogenic edema associated with intraparenchymal and subarachnoid hemorrhage. Diagnostic: Subacute thrombosis in the SSS and right ST. Page 3 of 25

4 Images for this section: Fig. 1: Axial unenhanced CT images shows an hiperdense area in the left frontal lobe, after contrast administration filling defects are seen in the SSS. Radiology, Complejo asistencial de Segovia - Segovia/ES Page 4 of 25

5 Fig. 2: MRI pulse sequences: sagittal and axial T1WI, coronal T2WI, FLAIR, axial T2*, TOF, MRI venography, MRI venography with contrast and DWI. Radiology, Complejo asistencial de Segovia - Segovia/ES Page 5 of 25

6 Findings and procedure details ANATOMICAL REVIEW CEREBRAL VENOUS DRAINAGE The cerebral venous system consists of a superficial and a deep system that drains into the venous sinus system and finally gets to the internal jugular veins. The veins are located on the surface of the cerebral hemispheres and not follow the arteries. Fig. 3 on page 19 Fig. 4 on page 19 SUPERFICIAL VENOUS SYSTEM: Drains the cerebral cortex and underlying white matter. External group: Superiors cerebral Veins are named for the lobe that they drain. Empty the superolateral side of the brain. Superficial middle cerebral vein: drains the lateral surface of the hemisphere. Superior anastomotic vein (Trolard) connects the SSS and Superficial middle cerebral vein. Internal Group: Collect blood from the inner side of the brain. Drain into the SSS. Inferior Group: Formed by the deep middle cerebral vein. It drains the lower surface of the hemisphere and the insula. It joins with the anterior cerebral veins and the striatum to form the basal vein (Rosenthal). DEEP VEIN SYSTEM: The deep system drains blood from the mass of brain tissue. Its formed by several veins draining into two main tributaries: Internal cerebral veins Basal vein of Rosenthal The vein of Galen is formed by the union of internal cerebral vein and basal vein. Page 6 of 25

7 The infraatentorial veins drain superiorly into the vein of Galen. DURAL VENOUS SINUSES: Are inclosed in the leaves of the dura, they collect the blood from the brain veins. Fig. 5 on page 19 The superior sagittal sinus (SSS) runs from the anterior aspect of the falx cerebri to its termination at the confluence of the sinuses. It receives venous blood from the internal and external aspects of the hemispheres and middle meningeal veins. The inferior sagittal sinus (ISS) runs by the lower aspect of the falx cerebri. It receives tributaries from the inner surface of both hemispheres and the corpus callosum. The straight sinus (SS) is located at the junction between the falx cerebri and the tentorium cerebeli. It drains to the confluence of sinuses. The transverse sinus (TS) drains from the confluence of the sinuses and run laterally along the interior surface of the occipital bone to the base of the petrous pyramid where becomes the sigmoid sinus. The cavernous sinus is located on both sides of the sella turcica. Communicates with orbital venous plexus and with the venous plexus of the sphenopalatine and pterygomaxillary fossae. The petrosal sinuses; the superior petrosal sinus receives blood from the cavernous sinus and the inferior petrosal sinus runs from the cavernous sinus to the jugular foramen, where joins the sigmoid sinus to form the internal jugular vein. IMAGING TECHNIQUE The actual techniques used to detect a CVT include CT venography, TOF (Time of flight) MR venography and MR venography with contrast; these play an important role in detecting this condition. CT is a often the first imaging used in the diagnostic given that is a technique rapid and almost always available. CT venography is comparable to MR venography in the diagnosis of CVT. TOF MR venography is very useful evaluating the intracranial venous system and has high sensitivity to slow flow. Some of the advantages are the no ionizated radiation and follow-up after treatment. IMAGING FINDINGS Page 7 of 25

8 The radiological findings are divided in: Indirect signs: edema, vascular congestion, infarction, subarachnoid hemorrhage. Fig. 6 on page 20 Direct signs:direct visualization of the thrombus. Fig. 7 on page 21 Some of the main radiological findings are: Cord sign:thrombus appears as a linear hyperdense area on unenhanced CT. Fig. 8: Cord sign. Axial unenhanced CT images sohws areas of hiperattenuation sugestive of thrombosis in the ST (arrows). References: Radiology, Complejo asistencial de Segovia - Segovia/ES Dense triangle sign:the thrombus appears as hyperdense triangle whitin the posterior aspect of the SSS in the axial slices. Page 8 of 25

9 Fig. 9: Dense triangle sign. Axial unenhanced CT images shows hiperattenuation within the SSS consistent with thrombous. References: Radiology, Complejo asistencial de Segovia - Segovia/ES Empty delta sign: Is the most frequently seen CT sign. At contrastenhanced images shows a central region of low attenuation (thrombosed sinus) surrounded by a dural enhancement. Page 9 of 25

10 Fig. 10: Empty delta sign. Axial contrast- enhanced CT images shows a central region of low attenuation consistent with a thrombosis in the SSS References: Radiology, Complejo asistencial de Segovia - Segovia/ES Fig. 11: Empty delta sign on MRI. Axial and coronal contrast enhanced MR venography images showing filling defects (arrows) within the right TS (a) and SSS (b) surrounded by dural enhancement. Page 10 of 25

11 References: Radiology, Complejo asistencial de Segovia - Segovia/ES Venous collateral flow:gyral and tentorial enhancement that can be extended to the withe matter due to a disruption of the blood- brain barrier. Fig. 12: Collateral flow. (a,b) Axial contrast enhanced MRI shows edema and mild mass effect in the temporal lobe (red arrows) with formation of collateral vessels (blue arrow). (c, d) Axial T2*WI and MR venography with contrast shows numerous venus collateral of the superficial veins. References: Radiology, Complejo asistencial de Segovia - Segovia/ES MRI is the most sensitive technique, the principal findings include the combination of the absence of normal flow void and the signal intensity alterationin the thrombosed sinus Page 11 of 25

12 Fig. 13: Absence of normal flow. (a) Coronal TOF MR Venography shows a complete absence of signal in right TS, Sigmoid sinus and internal jugular vein. (b,c) Another pacient with absence of signal in the SSS and bilateral ST due to thrombosis. References: Radiology, Complejo asistencial de Segovia - Segovia/ES The signal intensity of venous thrombi varies according the evolution of the thrombus and the hemoglobin states. -In the acute stage (0-5 days) the signal is isointense on T1WI and hypointense on T2WI (deoxyhemoglobin). -In the subacute state (6-15 days ) the signal is hyperintense on T1WI and T2WI due to the transformation of the hemoglobin to methemoglobin. Page 12 of 25

13 Fig. 14: Subacute thrombosis. (a,b,c) T1WI, T2WI and FLAIR WI showing hyperintense areas within the SSS (arrows in a,b) and within the ST (arrows in c). (d,e) Restricted diffusion and corresponding low signal on ADC map are seen. (f) Axial unenhanced CT image shows hiperattenuation within the SSS and in the internal cerebral veins (arrows). References: Radiology, Hospital universitario Puerta de Hierro -Madrid/ES -In chronic thrombosis with incomplete recanalization of the sinus the signal is iso or hyperintense on T2WI and isointense on T1WI. Page 13 of 25

14 Fig. 15: Chronic thrombosis. 68 years old male diagnosed with CVT 5 years ago, refers headache. (a) axial contrast- enhanced CT, (b) Coronal T2WI, (c,d,e) Contrast enhanced MR venography and (f) coronal TOF MR Venography shows filling defects in the right ST, the sigmoid sinus and the SSS with partial recanalization and increased collateral circulation consistent with chronic thrombosis. References: Radiology, Complejo asistencial de Segovia - Segovia/ES - Hyperintensity on Diffusion weigthed images and corresponding low signal on ADC maps can be useful to distinguish acute and subacute thrombosis from chronic thrombosis Fig. 16 on page 22 PARENCHYMAL DISORDERS The thrombus may obstruct venous drainage with increase pressure leading to vasogenic edema due to venous congestion, cytotoxic edema by cellular damage, cortical hemorrhage with subcortical extension and finally venous infarction that does not follow an arterial vascular territory. Page 14 of 25

15 Fig. 17: Parenchymal disorders associated with subacute thrombosis (a) Axial unenhanced CT image and (b) Axial T2WI shows intraparenchymal hematoma (arrow in a) asociated with important vasogenic edema in the left temporal lobe (arrow in b), (c) susceptibility defects in the superficial veins of the left temporal lobe (arrow in c). Hyperintensity within the confluence of the sinuses consistent with subacute thrombosis (arrow in d). References: Radiology, Complejo asistencial de Segovia - Segovia/ES Fig. 18: (a) Axial contras enhanced MRI shows filling defects within the rigth sigmoid sinus and ST with parietoccipital venous infarction associated (arrow in b). References: Radiology, Complejo asistencial de Segovia - Segovia/ES Page 15 of 25

16 The distribution of the lesions may indicate the location of the thrombus, thereby a frontal or parietal parasagittal abnormality is seen in SSS thrombosis while bleeding in temporal or occipital lobes indicates TS thrombosis, thrombosis of the deep venous system may produce changes in the basal ganglia and midbrain. Incomplete recanalization is visualized as irregular dural sinus and collateral vessels. PITFALLS False dense triangle: It can be seen in patients with dehydration,high hematocrit or subarachnoid or subdural hemorrhage underlying. False empty delta sign can be seen in neoplasms, hemorrhage or subdural empyema. A slow or turbulent flow can cause alterations in signal MRI. Fig. 19: Artefacts flow. Asymmetric signal intensity in the right ST is seen on T1WI (a), STIR FLAIR (b), T2 WI (c), after administration of contrast (d) Page 16 of 25

17 and on TOF venography (e) demonstrates that corresponds with slow flow and there is no evidence of thrombosis. References: Radiology, Complejo asistencial de Segovia - Segovia/ES Hypoplasia and atresia of the transverse sinuses. Fig. 20: (a) Axial contrast enhanced MR venography image and (b) axial contrast enhanced CT shows hypoplasia of the left transverse sinus, note the asymmetry between the two sinus (arrows). References: Radiology, Complejo asistencial de Segovia - Segovia/ES Flow gaps at TOF MR venography images more common in nondominant transverse sinuses with slow flow and the acquisition plain is not perpendicular. Arachnoid granulationsare round filling defects that simulate thrombosis with CSF density corresponding to protrusions within dural sinus. Page 17 of 25

18 Fig. 21: (a) Axial contrast enhanced MR venography image showing filling defects indicative of thrombus in the right TS (blue arrows) and arachnoid granulations in the left side (red arrows). (b) MIP image from contrast enhanced MRI shows round filling defects within the both ST consistent with arachnoid granulations. References: Radiology, Complejo asistencial de Segovia - Segovia/ES Page 18 of 25

19 Images for this section: Fig. 3: Coronal, sagittal and axial 3DTOF MR images showing normal venous anatomy Radiology, Complejo asistencial de Segovia - Segovia/ES Fig. 4: Volumetric reconstructions images from contrast- enhanced MRI venography Radiology, Complejo asistencial de Segovia - Segovia/ES Page 19 of 25

20 Fig. 5: Coronal and sagittal MIP images TOF MR venography, demonstrates the dural sinuses. Superior sagittal sinus (red), Inferior sagittal sinus (yellow), Straight sinus (green), Confluence of the sinuses (blue), Transverses sinuses (sky-blue),sigmoid sinuses (purple), Internal yugular vein (pink). Radiology, Complejo asistencial de Segovia - Segovia/ES Page 20 of 25

21 Fig. 6: Indirect signs: (a) Coronal T2W MRI shows edema in the left temporal lobe )arrow), (b) Axial T2*GRE shows irregular veins in the left hemisphere due to collateral drainage (arrow), c. Axial T2WI shows the presence of a thrombus in the SSS (circe) associated with an infarct in the right parietal lobe (arrow), (d) Axial T2*WI shows subarachnoid hemorrhage in the left frontal lobe (arrow). Radiology, Complejo asistencial de Segovia - Segovia/ES Page 21 of 25

22 Fig. 7: Direct signs:(a) axial T1WI MR showing an hyperintense area in the SSS consistent with subacute thrombosis. (b) Coronal contras- enhanced MRI shows filling defects within the rigth TS (arrow). Radiology, Complejo asistencial de Segovia - Segovia/ES Fig. 16: Acute Vs chronic thrombosis (a) T1WI shows an hyperintense area in the SSS, (b,c) DWI, restricted diffusion and corresponding low signal on ADC map consistent with acute thrombosis. (d) Axial contrast enhanced MR venography image showing filling Page 22 of 25

23 defects in the rigth ST, (e,f)dwi without restricted diffusion in a patient with chronic thrombosis. Radiology, Complejo asistencial de Segovia - Segovia/ES Page 23 of 25

24 Conclusion It is essential to become familiar with radiological findings of cerebral venous thrombosis as well as the entities included in the differential diagnosis, in order to optimize the diagnosis and prevent misinterpretation. A detailed knowledge of the anatomy of the cerebral venous system and its normal variants is essential for a correct diagnosis. Page 24 of 25

25 References Garg A. Vascular brain pathologies. Neuroimaging clinics of North America. Elsevier Inc; 2011 Nov;21(4): , ix. Ganeshan D, Narlawar R, McCann C, Jones HL, Curtis J. Cerebral venous thrombosis-a pictorial review. European journal of radiology Apr;74(1): H RM, Alexandre K, Antoine F, Annick H, Jean-Michel C, Marie-Christine J, et al. Thrombosis and Multidetector CT Angiography : Tips and Tricks. Radiographics a review publication of the Radiological Society of North America Inc. 2006;26:5-18. Leach J, Fortuna R, Jones B V, Gaskill-Shipley M-F. Imaging of Cerebral Venous Thrombosis : Current Techniques, Spectrum of Findings, and Diagnostic Pitfalls. Radiographics a review publication of the Radiological Society of North America Inc.2006; Page 25 of 25