- •Foreword
- •Preface
- •Acknowledgments
- •Contents
- •Contributors
- •1.2 Forehead Augmentation
- •1.2.1 Discussion
- •1.3.1 Discussion
- •1.4 Rhinoplasty
- •1.4.1 Discussion
- •1.5 Lip Augmentation
- •1.5.1 Discussion
- •1.6 Chin and Jaw Augmentation
- •1.6.1 Discussion
- •Further Reading
- •Forehead Augmentation
- •Rhinoplasty
- •Lip Augmentation
- •Jaw Augmentation
- •2: Imaging the Postoperative Orbit
- •2.1 Eyelid Weights
- •2.1.1 Discussion
- •2.2 Palpebral Springs
- •2.2.1 Discussion
- •2.3.1 Discussion
- •2.4.1 Discussion
- •2.5.1 Discussion
- •2.6.1 Discussion
- •2.7 Strabismus Surgery
- •2.7.1 Discussion
- •2.8 Glaucoma Surgery
- •2.8.1 Discussion
- •2.9 Scleral Buckles
- •2.9.1 Discussion
- •2.10 Keratoprostheses
- •2.10.1 Discussion
- •2.11 Intraocular Lens Implants
- •2.11.1 Discussion
- •2.12 Surgical Aphakia
- •2.12.1 Discussion
- •2.13 Pneumatic Retinopexy
- •2.13.1 Discussion
- •2.14 Intraocular Silicone Oil
- •2.14.1 Discussion
- •2.15.1 Discussion
- •2.16 Orbital Tissue Expanders
- •2.16.1 Discussion
- •2.17 Orbital Exenteration
- •2.17.1 Discussion
- •2.18.1 Discussion
- •Further Reading
- •Eyelid Weights
- •Palpebral Spring
- •Frontalis Suspension Ptosis Repair
- •Strabismus Surgery
- •Glaucoma Surgery
- •Scleral Buckles
- •Keratoprostheses
- •Intraocular Lens Implants
- •Surgical Aphakia
- •Pneumatic Retinopexy
- •Intraocular Silicone Oil
- •Orbital Tissue Expanders
- •Orbital Exenteration
- •3.1.1 Discussion
- •3.2 Septoplasty
- •3.2.1 Discussion
- •3.3.1 Discussion
- •3.4.1 Discussion
- •3.5 Nasal Packing Material
- •3.5.1 Discussion
- •3.6 Rhinectomy
- •3.6.1 Discussion
- •3.7 Sinus Lift Procedure
- •3.7.1 Discussion
- •3.8 Caldwell-Luc Procedure
- •3.8.1 Discussion
- •3.9 External Ethmoidectomy
- •3.9.1 Discussion
- •3.10.1 Discussion
- •3.11 FESS Complications
- •3.11.1 Discussion
- •3.11.2 Discussion
- •3.11.3 Discussion
- •3.11.4 Discussion
- •3.11.5 Discussion
- •3.11.6 Discussion
- •3.11.7 Discussion
- •3.11.8 Discussion
- •3.11.9 Discussion
- •3.11.10 Discussion
- •3.11.11 Discussion
- •3.12 Osteoplastic Flap with Frontal Sinus Obliteration
- •3.12.1 Discussion
- •3.13 Frontal Sinus Cranialization
- •3.13.1 Discussion
- •3.14 Paranasal Sinus Stents
- •3.14.1 Discussion
- •3.15 Frontal Sinus Trephination
- •3.15.1 Discussion
- •3.16.1 Discussion
- •3.17.1 Discussion
- •3.18 Maxillary Swing
- •3.18.1 Discussion
- •Further Reading
- •Septoplasty
- •Nasal Septal Button Prosthesis
- •Nasal Packing Material
- •Rhinectomy
- •Sinus Lift
- •Caldwell-Luc Procedure
- •External Ethmoidectomy
- •Functional Endoscopic Sinus Surgery
- •FESS Complications
- •Osteoplastic Flap with Frontal Sinus Obliteration
- •Frontal Sinus Cranialization
- •Paranasal Sinus Stents
- •Frontal Sinus Trephination
- •Maxillectomy and Palatectomy
- •Maxillary Swing
- •4.1 Occipital Nerve Stimulator
- •4.1.1 Discussion
- •4.2 Tissue Expander
- •4.2.1 Discussion
- •4.3 Temporal Fossa Implants
- •4.3.1 Discussion
- •4.4.1 Discussion
- •4.5.1 Discussion
- •4.6.1 Discussion
- •4.7 Scalp Tumor Recurrence
- •4.7.1 Discussion
- •4.8 Burr Holes
- •4.8.1 Discussion
- •4.9 Craniotomy
- •4.9.1 Discussion
- •4.10 Cranioplasty
- •4.10.1 Discussion
- •4.11 Autocranioplasty
- •4.11.1 Discussion
- •4.12.1 Discussion
- •4.14.1 Discussion
- •4.15 Box Osteotomy
- •4.16.1 Discussion
- •4.17.1 Discussion
- •4.18.1 Discussion
- •4.19 Subdural Drainage Catheters
- •4.19.1 Discussion
- •4.20.1 Tension Pneumocephalus
- •4.20.5 Pseudomeningoceles
- •4.20.6 Pseudoaneurysm
- •4.20.7 Postoperative Infection
- •4.20.8 Textiloma
- •4.20.9 Sunken Skin Flap Syndrome
- •4.20.10 External Brain Herniation
- •4.20.11 Bone Flap Resorption
- •Further Reading
- •Occipital Nerve Stimulator
- •Tissue Expander
- •Temporal Fossa Implant
- •Scalp Tumor Recurrence
- •Box Osteotomy
- •Absorbable Hemostatic Agents
- •Duraplasty and Sealant Agents
- •Burr Holes
- •Craniotomy
- •Cranioplasty
- •Autocranioplasty
- •Cranial Vault Reconstruction for Craniosynostosis
- •Cranial Vault Encephalocele Repair
- •Subdural Drainage Catheters
- •Intracranial Pressure Monitor
- •Cranial Surgery Complications
- •5.1 Intraoperative MRI
- •5.1.1 Discussion
- •5.2.1 Stereotactic Biopsy
- •5.2.1.1 Discussion
- •5.2.2 Resection Cavities
- •5.2.2.1 Discussion
- •5.2.3 Ommaya Reservoirs
- •5.2.3.1 Discussion
- •5.2.4 Chemotherapy Wafers
- •5.2.4.1 Discussion
- •5.2.5 Brachytherapy Seeds
- •5.2.5.1 Discussion
- •5.2.6.1 Discussion
- •5.3.1 Prefrontal Lobotomy
- •5.3.1.1 Discussion
- •5.3.2 Pallidotomy
- •5.3.2.1 Discussion
- •5.3.3 Cingulotomy
- •5.3.3.1 Discussion
- •5.3.4.1 Discussion
- •5.3.4.2 Thalamotomy
- •5.3.5 Deep Brain Stimulation (DBS)
- •5.3.5.1 Discussion
- •5.3.6.1 Discussion
- •5.3.7.1 Discussion
- •5.3.8.1 Discussion
- •5.3.9.1 Discussion
- •5.3.10 Corticectomy
- •5.3.10.1 Discussion
- •5.3.11.1 Discussion
- •5.3.12.1 Discussion
- •5.3.13 Callosotomy
- •5.3.13.1 Discussion
- •5.3.14 Anterior Temporal Lobectomy
- •5.3.14.1 Discussion
- •5.3.15.1 Discussion
- •5.3.16 Hemispherectomy
- •5.3.16.1 Discussion
- •Further Reading
- •Intraoperative MRI
- •Brain Tumor Surgery
- •Stereotactic Biopsy
- •Resection Cavities
- •Postoperative Hemorrhagic Lesions
- •Ommaya Reservoirs
- •Chemotherapy Wafers
- •Brachytherapy Seeds
- •GliaSite Radiation Therapy System
- •Prefrontal Lobotomy
- •Pallidotomy
- •Cingulotomy
- •Thalamotomy
- •Deep Brain Stimulation (DBS)
- •Epidural Motor Cortex Stimulator
- •Neural Interface System (BrainGate)
- •Corticectomy
- •Selective Disconnection
- •Callosotomy
- •Anterior Temporal Lobectomy
- •Hemispherectomy
- •6.1 Types of Procedures
- •6.1.1 External Ventricular Drainage
- •6.1.1.1 Discussion
- •6.1.2.1 Discussion
- •6.1.3 Atypical Ventricular Shunts
- •6.1.3.1 Discussion
- •6.1.4 Ventriculosubgaleal Shunts
- •6.1.4.1 Discussion
- •6.1.5.1 Discussion
- •6.1.6.1 Discussion
- •6.1.7 Subdural-Peritoneal Shunts
- •6.1.7.1 Discussion
- •6.1.8.1 Discussion
- •6.1.9.1 Discussion
- •6.1.10 Lumboperitoneal Shunts
- •6.1.10.1 Discussion
- •6.1.11 Third Ventriculocisternostomy
- •6.1.11.1 Discussion
- •6.1.12.1 Discussion
- •6.1.13 Aqueductoplasty
- •6.1.13.1 Discussion
- •6.1.14.1 Discussion
- •6.2.1.1 Discussion
- •6.2.2.1 Discussion
- •6.2.3 Intraventricular Fat Migration
- •6.2.3.1 Discussion
- •6.2.4.1 Discussion
- •6.2.5.1 Discussion
- •6.2.6 Slit Ventricle Syndrome
- •6.2.6.1 Discussion
- •6.2.7.1 Discussion
- •6.2.8 Shunt-Associated Infections
- •6.2.8.1 Discussion
- •6.2.9.1 Discussion
- •6.2.10.1 Discussion
- •6.2.11.1 Discussion
- •6.2.12 Peritoneal Pseudocysts
- •6.2.12.1 Discussion
- •6.2.13.1 Discussion
- •6.2.14 Tumor Seeding
- •6.2.14.1 Discussion
- •6.2.15 Shunt Catheter Calcification
- •6.2.15.1 Discussion
- •6.2.16.1 Discussion
- •6.2.17.1 Discussion
- •Further Reading
- •Types of Procedures
- •External Ventricular Drainage
- •Ventriculoperitoneal Shunts
- •Atypical Ventricular Shunts
- •Ventriculosubgaleal Shunts
- •Subdural-Peritoneal Shunts
- •Lumboperitoneal Shunt
- •Third Ventriculostomy
- •Aqueductoplasty
- •Fourth Ventricular Stenting
- •Complications
- •Intraventricular Fat Migration
- •Slit Ventricle Syndrome
- •Shunt-Associated Infections
- •Shunt Malposition and Migration
- •Pseudocysts
- •Cerebrospinal Fluid Leak Syndrome
- •Tumor Seeding
- •Shunt Catheter Calcifications
- •7.1.1 Discussion
- •7.2.1 Discussion
- •7.3.1 Discussion
- •7.4.1 Discussion
- •7.5.1 Discussion
- •7.6.1 Discussion
- •7.7 Radiosurgery for Vestibular Schwannomas
- •7.7.1 Discussion
- •Further Reading
- •Anterior Craniofacial Resection
- •Transsphenoidal Resection
- •Middle Cranial Fossa Reconstruction
- •Surgical Approaches for Vestibular Schwannoma Resection
- •8.1.1 Discussion
- •8.2 Auriculectomy
- •8.2.1 Discussion
- •8.3 Auricular Reconstruction
- •8.3.1 Discussion
- •8.4.1 Discussion
- •8.5 Atresiaplasty
- •8.5.1 Discussion
- •8.6.1 Discussion
- •8.7.1 Discussion
- •8.8 Ossicular Interposition
- •8.8.1 Discussion
- •8.9.1 Discussion
- •8.10.1 Discussion
- •8.11.1 Discussion
- •8.12 Atticotomy
- •8.12.1 Discussion
- •8.13.1 Discussion
- •8.14.1 Discussion
- •8.15.1 Discussion
- •8.16 Temporal Bone Resection
- •8.16.1 Discussion
- •8.17 Cochlear Implants
- •8.17.1 Discussion
- •8.18.1 Discussion
- •8.19.1 Discussion
- •8.20.1 Discussion
- •8.21.1 Discussion
- •8.22 Labyrinthectomy
- •8.22.1 Discussion
- •8.23 Vestibular Nerve Section
- •8.23.1 Discussion
- •8.24.1 Discussion
- •8.25.1 Discussion
- •Further Reading
- •BAHA Device
- •Auriculectomy
- •Auricular Reconstruction
- •Canaloplasty and Meatoplasty
- •Atresiaplasty
- •Myringoplasty and Tympanoplasty
- •Incus Interposition
- •Ossicular Prosthesis Complications
- •Transcanal Atticotomy
- •Mastoidectomy Complications
- •Lateral Temporal Bone Resection
- •Cochlear Implants
- •Cochlear Implant Complications
- •Auditory Brainstem Stimulator
- •Repair of Perilymphatic Fistula
- •Labyrinthectomy
- •Vestibular Nerve Sectioning
- •Tube Drainage of Cholesterol Cysts
- •9.1 Vertical Ramus Osteotomy
- •9.1.1 Discussion
- •9.2 Sagittal Split Osteotomy
- •9.2.1 Discussion
- •9.3 Genioplasty
- •9.3.1 Discussion
- •9.4.1 Discussion
- •9.5 Mandibular Distraction
- •9.5.1 Discussion
- •9.6 LeFort I Osteotomy
- •9.6.1 Discussion
- •9.7 LeFort III Osteotomy
- •9.7.1 Discussion
- •9.8.1 Discussion
- •9.9 Mandibulotomy
- •9.9.1 Discussion
- •9.10 Enucleation
- •9.10.1 Discussion
- •9.11 Cyst Decompression
- •9.11.1 Discussion
- •9.12 Coronoidectomy
- •9.12.1 Discussion
- •9.13.1 Discussion
- •9.14.1 Discussion
- •9.15.1 Discussion
- •9.16.1 Discussion
- •9.17.1 Discussion
- •9.18.1 Discussion
- •9.19.1 Discussion
- •9.20.1 Discussion
- •Further Reading
- •Vertical Ramus Osteotomy
- •Sagittal Split Osteotomy
- •Genioplasty
- •Mandibular Angle Augmentation
- •Mandibular Distraction
- •Lefort I Surgery
- •Lefort III Surgery
- •Fixation of Mandible Fractures
- •Mandibulotomy
- •Enucleation
- •Cyst Decompression
- •Coronoidectomy
- •Eminectomy and Meniscal Plication
- •10: Imaging the Postoperative Neck
- •10.1 Reconstruction Flaps
- •10.1.1 Discussion
- •10.2 Neck Dissection
- •10.2.1 Discussion
- •10.3 Parotidectomy
- •10.3.1 Discussion
- •10.4.1 Discussion
- •10.5 Facial Reanimation
- •10.5.1 Discussion
- •10.6.1 Discussion
- •10.7.1 Discussion
- •10.8 Transoral Robotic Surgery
- •10.8.1 Discussion
- •10.9 Sistrunk Procedure
- •10.9.1 Discussion
- •10.10 Laryngectomy
- •10.10.1 Discussion
- •10.11.1 Discussion
- •10.12 Montgomery T-Tubes
- •10.12.1 Discussion
- •10.13 Salivary Bypass Stent
- •10.13.1 Discussion
- •10.14 Laryngeal Stents
- •10.14.1 Discussion
- •10.15.1 Discussion
- •10.16 Arytenoid Adduction
- •10.16.1 Discussion
- •10.17 Arytenoidectomy
- •10.17.1 Discussion
- •10.18 Laryngeal Cartilage Remodeling
- •10.18.1 Discussion
- •10.19 Tracheotomy
- •10.19.1 Discussion
- •10.20 Thyroidectomy
- •10.20.1 Discussion
- •10.21.1 Discussion
- •10.22 Brachytherapy
- •10.22.1 Discussion
- •10.23 Vagal Nerve Stimulation
- •10.23.1 Discussion
- •Further Reading
- •Reconstruction Flaps
- •Facial Reanimation
- •Tonsillectomy and Adenoidectomy
- •Transoral Robotic Surgery
- •Neck Dissection
- •Parotidectomy
- •Salivary Duct Stenting
- •Laryngectomy
- •Montgomery T-Tubes
- •Salivary Bypass Stents
- •Laryngeal Stents
- •Arytenoid Adduction
- •Arytenoidectomy
- •Laryngeal Cartilage Remodeling
- •Tracheotomy
- •Thyroidectomy
- •Neck Exploration and Parathyroidectomy
- •Sistrunk Procedure
- •Brachytherapy
- •Vagal Nerve Stimulation
- •11: Imaging of Postoperative Spine
- •11.1 Overview
- •11.2 Spine Decompression
- •11.2.1.1 Discussion
- •11.2.2 Laminectomy
- •11.2.2.1 Discussion
- •11.2.3 Facetectomy
- •11.2.3.1 Discussion
- •11.2.4 Microdiscectomy
- •11.2.4.1 Discussion
- •11.2.5 Laminoplasty
- •11.2.5.1 Discussion
- •11.2.6 Vertebrectomy
- •11.2.6.1 Discussion
- •11.2.7 Cordectomy
- •11.2.7.1 Discussion
- •11.3.1 Halo and Traction Devices
- •11.3.1.1 Discussion
- •11.3.2 Bone Graft Materials
- •11.3.2.1 Discussion
- •11.3.3 Implantable Bone Stimulators
- •11.3.3.1 Discussion
- •11.3.4 Odontoid Screw Fixation
- •11.3.4.1 Discussion
- •11.3.5 Occipitocervical Fusion
- •11.3.5.1 Discussion
- •11.3.6 Anterior Cervical Fusion
- •11.3.6.1 Discussion
- •11.3.7.1 Discussion
- •11.3.8 Posterior Fusion
- •11.3.8.1 Discussion
- •11.3.9 Scoliosis Rods
- •11.3.9.1 Discussion
- •11.3.10 Vertebral Stapling
- •11.3.10.1 Discussion
- •11.3.11 Vertical Expandable Prosthetic Titanium Rib (VEPTR)
- •11.3.11.1 Discussion
- •11.3.12 Interbody Fusion
- •11.3.12.1 Discussion
- •11.4.1 Total Disc Replacement
- •11.4.1.1 Discussion
- •11.4.2.1 Discussion
- •11.4.3.1 Discussion
- •11.4.4 Dynamic Facet Replacement
- •11.4.4.1 Discussion
- •11.4.5 Dynamic Rods
- •11.4.5.1 Discussion
- •11.5.1 Overview
- •11.5.2.1 Discussion
- •11.5.3.1 Discussion
- •11.5.4.1 Discussion
- •11.5.5 Cerebrospinal Fluid Leak
- •11.5.5.1 Discussion
- •11.5.6.1 Discussion
- •11.5.7 Surgical Site Infections
- •11.5.7.1 Discussion
- •11.5.8 Postoperative Neuritis
- •11.5.8.1 Discussion
- •11.5.9 Arachnoiditis
- •11.5.9.1 Discussion
- •11.5.10.1 Discussion
- •11.5.11 Postoperative Synovial Cyst
- •11.5.11.1 Discussion
- •11.5.12 Residual/Recurrent Tumors
- •11.5.12.1 Discussion
- •11.5.13 Inclusion Cysts
- •11.5.13.1 Discussion
- •11.5.14.1 Discussion
- •11.5.15 Retained Surgical Tools
- •11.5.15.1 Discussion
- •11.5.16 Gossypiboma
- •11.5.16.1 Discussion
- •11.5.17.1 Discussion
- •11.5.18 Postoperative Deformity
- •11.5.18.1 Discussion
- •11.6.1 Discussion
- •11.7 Spinal Cord Stimulators
- •11.7.1 Discussion
- •11.8 Filum Terminale Sectioning
- •11.8.1 Discussion
- •11.9.1 Vertebral Augmentation
- •11.9.1.1 Discussion
- •11.9.2 Kiva Device
- •11.9.2.1 Discussion
- •11.9.3 Sacroplasty
- •11.9.3.1 Discussion
- •11.9.4.1 Discussion
- •11.9.5.1 Discussion
- •11.9.6.1 Discussion
- •Further Reading
- •Overview
- •Laminectomy
- •Facetectomy
- •Microdiscectomy
- •Laminoplasty
- •Vertebrectomy
- •Cordectomy
- •Bone Graft Materials
- •Implantable Bone Stimulators
- •Odontoid Screw Fixation
- •Anterior Cervical Fusion
- •Posterior Fusion
- •Occiptiocervical Fusion
- •Scoliosis Rods
- •Vertebral Stapling
- •Interbody Fusion
- •Nucleus Pulposus Replacement
- •Dynamic Facet Replacement
- •Dynamic Rods
- •Cerebrospinal Fluid Leak
- •Seromas and Hematomas
- •Postoperative Infection
- •Postoperative Neuritis
- •Arachnoiditis
- •Postoperative Synovial Cyst
- •Residual/Recurrent Tumors
- •Inclusion Cysts
- •Retained Surgical Tools
- •Gossypiboma
- •Postoperative Deformity
- •Intrathecal Spinal Infusion Pump
- •Spinal Cord Stimulators
- •Filum Terminale Sectioning
- •Kiva Device
- •Sacroplasty
- •Percutaneous Spine Fusion
- •CT-Guided Epidural Blood Patch
- •12.1 Vascular Surgery
- •12.1.1.1 Discussion
- •12.1.2.1 Discussion
- •12.1.3.1 Discussion
- •12.1.4.1 Discussion
- •12.1.6.1 Discussion
- •12.1.7 Carotid Endarterectomy
- •12.1.7.1 Discussion
- •12.1.8 Carotid Body Stimulation
- •12.1.8.1 Discussion
- •12.1.9 Adjustable Vascular Clamp
- •12.1.9.1 Discussion
- •12.1.10.1 Discussion
- •12.2 Endovascular Surgery
- •12.2.7 Endovascular Reconstructive Treatment for Acute Ischemic Stroke Using Intra-arterial Thrombolysis or Embolectomy
- •12.2.10 Endovascular Stent Reconstructive Treatment for Extracranial Cerebrovascular Occlusive Disease
- •12.2.11 Endovascular Reconstructive Treatment for Active Extracranial Hemorrhage or Pseudoaneurysm
- •Further Reading
- •Vascular Surgery
- •Aneurysm and Hemostatic Ligation Clips
- •Intracranial Aneurysm Muscle Wrap
- •Vascular Malformation Surgery
- •Carotid Endarterectomy
- •Carotid Body Stimulation
- •Adjustable Vascular Clamp
- •Reconstruction of the Great Vessels
- •Endovascular Surgery
- •General Imaging Considerations Following Endovascular Cerebrovascular Procedures
- •Endovascular Treatment for Aneurysms
- •Endovascular Stent Reconstructive Treatment for Extracranial Cerebrovascular Occlusive Disease
- •Endovascular Reconstructive Treatment for Active Extracranial Hemorrhage or Pseudoaneurysm
- •Endovascular Treatment for Intracranial Venous Stenosis and Occlusion
- •Index
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6.2.3\ Intraventricular Fat Migration
6.2.3.1\ Discussion
Fragments of subcutaneous adipose tissue can uncommonly migrate into the intracranial cisterns and ventricular system either during placement of a cerebrospinal fluid shunt catheter, since the catheter is tunneled through subcutaneous fat. This complication is apparent on MRI and CT as nodules with fat characteristics within the ventricles or cisterns (Fig. 6.32) can be adherent to the ventricular walls. Nevertheless, patients are often not symptomatic from this.
Fig. 6.31 Chronic calcified subdural hematoma. Coronal CT image shows peripherally calcified bilateral cerebral convexity subdural collections in a patient with longstanding ventricular shunting
Fig. 6.32 Intraventricular fat. The patient underwent recent lumboperitoneal shunt insertion. Coronal CT image shows fat-attenuation material within the suprasellar cistern and right Sylvian fissure (arrows)
6 Imaging of Cerebrospinal Fluid Shunts, Drains, and Diversion Techniques |
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6.2.4\ MRI-Induced Programmable
Valve Setting Alteration
6.2.4.1\ Discussion
Recurrent hydrocephalus in patients with indwelling ventricular shunts is a sign of shunt failure. Of note, high-field-strength MRI can alter the pressure setting of most percutaneous programmable cerebrospinal fluid shunts and may also result in acute hydrocephalus, mimicking shunt malfunction, if the setting is not
checked and reset after the scan (Fig. 6.33). The accumulation of cerebrospinal fluid can lead to ventricular enlargement, unless there is extensive preexisting ventricular scarring that limits ventricular expansion. Enlargement of the temporal horns is among the earliest findings of this complication. Other signs include effacement of the sulci and transependymal flow of cerebrospinal fluid. Hydrocephalus can result in sutural diastasis and enlargement of cranial diameter in children.
a |
b |
|
c |
d |
|
Fig. 6.33 MRI-induced programmable valve setting alteration. The patient with a percutaneously programmable cerebrospinal fluid shunt, presented acutely obtunded after undergoing MRI at 1.5T the previous day. The pressure settings were not checked following MRI. The following day, the patient was minimally responsive and was noted that the pressure setting changed from 0.5 to 2.5 on
the Medtronic Strata valve. This change was presumably secondary to the magnetic field. Axial T2-weighted MRI (a) shows no ventricular dilatation. Shunt survey (b) obtained before the MRI shows a pressure setting of 0.5. Axial CT image (c) obtained the day after the MRI shows acute massive hydrocephalus and the subsequent shunt survey (d) shows a pressure setting of 2.5
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6.2.5\ Ventricular Loculations
and Isolated Ventricles
6.2.5.1\ Discussion
The formation of loculations of cerebrospinal fluid within the ventricular system can lead to shunt failure. The compartmentalized collection of cerebrospinal fluid can lead to symptoms of hydrocephalus and may be caused by adhesions from prior hemorrhage or infection, for example. CT ventriculography performed by injecting contrast into the shunt catheter can be used to delineate the presence of loculations by the lack of communication of the contrast material with the rest of the ventricular system (Fig. 6.34). Similarly, an isolated or trapped ventricle is an uncommon phenomenon that can occur in the setting of ventricular shunting with adhesion formation and represents a form of focal hydrocephalus. The significance of this complication is that
it can exert mass effect upon surrounding structures. On imaging, disparate sizes of the ventricles are apparent, and contrast does not enter the trapped ventricle on CT ventriculography if the contrast is injected into the other portions of the ventricular system (Fig. 6.35). The level of obstruction is often at the foramen of Monro, but can occur anywhere in the ventricular system. Treatment may consist of ventricular catheter repositioning, septostomy, foramen of Monro reconstruction, or implantation of a catheter into the affected ventricle. Isolated ventricles that are not enlarging can be difficult to differentiate from asymmetric ventricles, which may also be encountered after shunting and do not require treatment. Midline shift and progressive increase in size of the ventricle suggest trapping over simple asymmetry of the ventricles. If there is any doubt, short interval imaging follow-up can be performed.
Fig. 6.34 Ventricular loculation. Axial CT ventriculogram shows the injected contrast confined to a cystic compartment (arrow)
Fig. 6.35 Isolated fourth ventricle. Sagittal CT ventriculogram shows the injected contrast confined to the third and lateral ventricles and a markedly expanded fourth ventricle