Cerebellomedullary compression in recessive craniometaphyseal dysplasia

Craniometaphyseal dysplasia (CMD) is a very rare disorder of bone remodelling characterised by sclerosis of the skull base, vault and facial bones and metaphyseal splaying of tubular bones. The recessive form appears to be more severe than the dominant. Cranial nerve deficits have been reported in infancy and early childhood in a few patients, but the long-term history of recessive CMD is not well documented. We report cerebellomedullary compression in a girl with recessive CMD recognised at 14 years because of progressive truncal ataxia. MRI revealed backward angulation of the thickened clivus, narrowing of the foramen magnum and upward deviation of the cerebellum by a markedly thickened occipital squama, tonsillar herniation and obliteration of the infratentorial cerebrospinal fluid spaces. Posterior cranial fossa decompression resulted in marked improvement of the ataxia. Compression of posterior cranial fossa structures has to be considered in the natural history and management of CMD.

[Color-coded duplex ultrasonography of extracranial vascular lesions]

The diagnostic potential of color-coded duplex sonography in extracranial vascular lesions is evaluated with reference to the literature. Indications for the applications of color-coded duplex sonography comprise congenital vascular anomalies, arteriosclerotic lesions, dissections, aneurysms, arteriovenous fistulas and glomus tumors. New applications consist include monitoring after vascular interventional procedures. Color-coded duplex sonography allows recognition of congenital anatomic variants like agenesis of the internal carotid artery and variations of the origin of the vertebral artery. By superior surface delineation, characterization and quantification of plaques and stenoses are improved because of a new development in ultrasound technique. In cases of vessel dissection color-coded ultrasound is able to depict the dissection membrane, pulse synchronous flow reversal and "reentry" phenomena. Significant carotid bulb ectasia can be demonstrated and differentiated from aneurysm formation by 3D technique and angio-CT. Extracranial arteriovenous fistulas may be localized and detailed with respect to feeding arteries and draining veins. Glomus caroticum and jugular tumors are characterized by a high degree of vascularity and a position in the carotid bifurcation and within the jugular vein, respectively. The position of intravascular devices like detachable balloons and catheters was precisely demonstrated.

CONCLUSION

Color-coded duplex sonography may assume a leading role in the noninvasive evaluation of extracranial vascular lesions. It provides criteria for the necessity and rational application of additional diagnostic procedures (MR, MRA, CT, DSA).

[Quiz on an unusual orbital masquerade syndrome]

BACKGROUND

After consulting the here presented CT-images of the orbit, the question was raised whether the ocular bulbus was really enucleated or the anamnesis was wrong and a lymphoma existed in the orbit. We will therefore discuss a case of a special follow-up after an enucleation with implantation of a "Bangerter Plomb".

CASE REPORT

In 1988 the patient, born on February 1, 1947, underwent an enucleation of the right eye with implantation of a "Bangerter Plomb" because of posttraumatic phthisis dolorosa. The postoperative follow up was complicated by a reactive psychopathological development with automutilation. In 1992, a Non-Hodgkin lymphoma of the mandibula was detected and treated. During the year of 1994, a painful swelling of the right orbit developed. The orbital CT suggested a recurrence of the lymphoma in the right eye, which seemed to be still in place. The biopsy however showed an abscess cavity and some parts of the Bangerter implant.

CONCLUSIONS

The abscess cavity with the connected muscles and the interruption of the optic nerve which was only partially visible simulated the presence of a bulbus; the rest of the implant, on the other hand, simulated the presence of a lymphoma. The two main reasons for the infection were an early dehiscence of the wound and the automutilation. This "syndrome of masquerade" could have been detected earlier if the ophthalmologists and the neuroradiologists would have discussed the CT-images together earlier.

[Anatomy and pathology of the parotid gland. COrrelation with magnetic resonance tomography]

Due to a very complex embryological development a variety of different tissues are mixed together within the parotid gland. Secondary degenerative metaplastic and regenerative alterations result in additional tissue variety. Epithelial cells of distinct differentiation, lymphatic tissue, partly within lymph nodes, partly in clusters, sebaceous tissue, fat and peripheral nervous tissue may be the origin of a pathological neoplastic or inflammatory intraparotid lesion. MRI is an optimal tool for the delineation of the anatomy of the parotid gland and of various intraparotid lesions and often permits differentiation among malignant and benign neoplastic and inflammatory lesions. The morphology of the different pathological lesions on MRI reflects the underlying histopathology. Due to great interindividual variations in the tissue characterization of a specific intraparotid lesion, great differences in MR morphology have to be expected.

The missing temporal crescent

PURPOSE

We studied clinically the representation of the monocular temporal crescent in the human visual cortex and noted the importance of using the perimetric techniques best suited to detect this visual field defect and to study patients in whom the temporal crescent is missing.

METHODS

Goldmann perimetry and high-resolution magnetic resonance imaging were performed in two patients with vascular lesions located in the anterior striate cortex.

RESULTS

A monocular visual field defect, the missing temporal crescent, was found on the side contralateral to the lesion.

CONCLUSIONS

The perimetric-magnetic resonance imaging correlation is in exquisite agreement with recent information about the representation of the visual field in the human primary visual cortex. Reports of this specific perimetric finding are rare, in part because of underdetection with currently used perimetric techniques that concentrate on the central 30 degrees of the visual field.

How angioarchitecture of cerebral arteriovenous malformations should influence the therapeutic considerations

PURPOSE

To evaluate the angioarchitectural criteria of complex cerebral arteriovenous malformations (AVMs), concerning the risk of hemorrhage and therapy planing.

METHODS

The magnetic resonance (MR) imaging and neuroangiographic findings of 227 AVMs (223 patients) were retrospectively evaluated. Statistical analysis was used to define the relative frequency of these lesions for hemorrhage in correlation with various parameters (i.e. age of the patient, size, location, associated aneurysms).

RESULTS

Onset of symptoms was between 21 and 40 years of age in 50% of cases. The ratio of centrally to convexially located lesions was 1:2. Convexial AVMs are classified by MR imaging into sulcal and gyral, according to the arterial supply (by terminal or transit feeding arteries, respectively), as proven by super-selective neuroangiography. Central location of the AVM, size of the nidus smaller than 2 cm diameter, and presence of related aneurysms, are high risk factors for hemorrhage. AVMs with one or two draining enlarged veins, or those without reflux presented a higher incidence of hemorrhage as well.

CONCLUSION

A team approach is required for the choice of the therapeutic method in patients with AVMs. Our results allow an approximate prognosis concerning the risk of hemorrhage in these patients and should be taken in consideration for the precise therapeutic planing.

Interventional neuroradiology of lesions of the skull base

Preoperative embolization has been incorporated definitively into the multidisciplinary therapy strategy for lesions of the skull base. Clinical and anatomic knowledge of the pathology of the skull base, as well as experience with embolization, is the basis for therapeutic success. Clinical knowledge will lead to adequate patient selection, whereas profound anatomic knowledge and mastery of endovascular techniques will avoid predictable complications. Provided these conditions are taken into consideration, embolization of lesions of the skull base yields convincing therapeutic and technical results. Preoperative embolization of skull base tumors should not be associated with mortality or morbidity because most of these diseases are histologically benign and the interventional procedure is done as a preoperative step and not as a curative one. Major complications such as cerebral stroke, blindness, or cranial nerve palsies are results of the application of inappropriate techniques or of poor evaluation of angiographic findings, and should be avoided in the majority of cases. Minor complications are related to inadvertent occlusion of cutaneous, muscular, or osseous branches of the ECA. They are sometimes unavoidable and may include pain, skin necrosis, and trismus. Nevertheless, state-of-the-art external carotid embolization should--in skilled hands--have a permanent morbidity below 1% and no mortality.

Idiopathic, herpetic, and HIV-associated facial nerve palsies: abnormal MR enhancement patterns

PURPOSE

To determine specific criteria that can be used to define normal versus abnormal MR contrast enhancement of the facial nerve.

METHODS

Twenty-three patients with acute unilateral inflammatory peripheral facial nerve palsy were examined on a 1.5-T MR using multiplanar T1-weighted spin-echo sequences before and after injection of gadopentetate dimeglumine. These MR patterns were compared with those of healthy control subjects.

RESULTS

The normal facial nerve usually showed a mild to moderate enhancement of the geniculate ganglion and the tympanic-mastoid segment. The intracanalicular-labyrinthine segment did not enhance. All patients showed abnormal enhancement of the distal intracanalicular and the labyrinthine segment. An intense enhancement could be observed in the geniculate ganglion and the proximal tympanic segment, especially in herpetic palsy. Associated enhancement of the vestibulocochlear nerve was seen in herpetic and idiopathic palsy. Enhancement of the inner ear structures was detected only in herpetic palsy.

CONCLUSIONS

Abnormal contrast enhancement of the distal intracanalicular and the labyrinthine facial nerve segment is observed in all patients and is the only diagnostically reliable MR feature proving an inflammatory facial nerve lesion. The intense enhancement of the geniculate ganglion and the proximal tympanic segment is possibly correlated with the reactivation of the latent infection in the sensory ganglion. The abnormal enhancement results from breakdown of the blood-peripheral nerve barrier and/or from venous congestion in the venous plexuses of the epi- and perineurium.

[Possibilities of catheter therapy in vascular stenosis, vascular abnormalities, tumors and hemorrhages. Synopsis of an interdisciplinary colloquium]

Modern interventional catheter-technics allow amelioration of arterial blood flow by dilatation of narrowed or recanalization of closed coronary and peripheral arteries. Patients with chronic or unstable angina pectoris not responding to therapy can thus be treated successfully by percutaneous dilatation (PTCA). In peripheral occlusive disease balloon catheterization sometimes in combination with local fibrinolysis and thrombectomy may prevent amputation. On the other hand, cerebral malformations of arteries, aneurysms and tumors can be eliminated by artificial occlusion. Therapeutic embolization is also increasingly used in acute or recurrent haemorrhage in lungs, spleen and gastrointestinal tract. It may also be used as palliating therapy in malignancies. Medical indications and limitations of the various catheter techniques in cardiology, angiology, neurology and interventional radiology are discussed.

[Magnetic resonance imaging in neuroradiology. Indications and applications]

On the basis of own experience with 250 MR-Angiographies and with reference to the literature the authors report on the role MR-Angiography is assuming in neuroradiological diagnostic procedures. As a noninvasive method MR-Angiography contributes to the evaluation of vessel stenosis and occlusion, venous sinus thrombosis and neurovascular compression syndromes. It supports the work-up of space-occupying lesions, as well as arteriovenous malformations and aneurysms. In addition to the diagnosis, follow-up examinations serve as a noninvasive means of therapy control particularly after interventional endovascular procedures. Knowledge of the diagnostic capabilities and limitations, the choice of the correct examination technique and modification of technical variables contribute to establish MR-Angiography as a valuable adjunct to MR imaging.

Age distribution and iron dependency of the T2 relaxation time in the globus pallidus and putamen

Heavily T2-weighted spin echo sequences of the brain show age-dependent low signal intensity in many extrapyramidal nuclei. Although it has been suggested that this low intensity results from non-haem iron, the specific influence of non-haem iron on the T2 relaxation time has not been quantified and remains controversial. The T2 relaxation times of the globus pallidus and putamen were measured from MRI at 1.5T in 27 healthy patients, by using a mathematical model. They were then plotted as a function of age and compared to the curve of age-dependent iron concentration determined post mortem. The curves of T2 relaxation time in the basal ganglia are congruent with published curves of iron concentration, indicating a high probability that the changes in T2 relaxation times and the low signal in the basal ganglia result from the local, age-dependent iron deposition. Individual measurements of T2 relaxation time show less variation before than after 45 years of age, indicating the influence of a second, more individual factor.

Gradual facial palsy and intrapetrous internal carotid aneurysm: a case report

A case of aneurysm of the horizontal intratemporal carotid artery with compression of the facial nerve is presented. Exclusion of the aneurysm with an intraluminal balloon did not relieve the facial nerve compression. Surgical resection of the aneurysm and repair of the facial nerve continuity was successfully performed through a combined transmastoid supralabyrinthine approach, after permanent balloon occlusion of the internal carotid artery.

[Neuroradiology of the spinal cord]

In recent years MR has assumed a central and key role in neuroradiological evaluation of the spinal cord. Because of its noninvasiveness and high sensitivity in the detection of intramedullary lesions, it represents the method of choice today for the work-up of acute, chronic and traumatic myelopathies. The main limiting factor of MR is its rather low specificity. For this reason the clinical history as well as the neurological and laboratory findings continue to be of major importance in arriving at a definite diagnosis. The method is contraindicated in patients with pacemakers or other intracorporeal paramagnetic devices. It is relatively contraindicated in claustrophobic patients. In these cases MR should be replaced by myelography or CT-myelography. For the diagnosis of vascular diseases of the spinal cord, specifically vascular malformations and hypervascular tumors (e.g. hemangioblastoma), selective spinal angiography represents an essential adjunct to MR. Selective angiography can also be used therapeutically to treat preoperatively or definitely vascular malformations (i.e. interventional neuroradiology).

Central neurocytoma: histopathological variants and therapeutic approaches

The central neurocytoma has recently been added to the differential diagnosis of intraventricular tumors. Histopathologically, this tumor is characterized by a uniform neoplastic cell population with features of neuronal differentiation. Central neurocytomas occur in young adults, develop in the area of the foramen of Monro, and are usually associated with the septum pellucidum. Initial reports appeared to indicate that these tumors are benign lesions with a favorable postoperative prognosis. The authors present clinical and neuropathological findings in a series of eight patients with central neurocytoma. An anterior transcallosal microneurosurgical approach yielded good outcomes. Postoperative radiation therapy was restricted to two patients with a malignant variant of central neurocytoma and one patient with a recurrent tumor. Observations of anaplastic variants of this neoplasm in two cases and local tumor recurrences in three indicate that the biological behavior and postoperative prognosis of central neurocytoma may not always be as favorable as previously assumed.

Blood-brain-barrier disruption in acute Wernicke encephalopathy: MR findings

The clinical and MR features of an alcoholic woman with Wernicke encephalopathy are reported. During the acute stage Gd-diethylenetriamine pentaacetic acid enhanced MR revealed damage of the blood-brain barrier bilaterally and symmetrically adjacent to the third ventricle, cerebral aqueduct, and fourth ventricle. The enhancement disappeared after successful thiamine therapy, as demonstrated in a repeat postcontrast MR 1 week later.

Traumatic carotid cavernous sinus fistula due to a gun shot injury

A case of a traumatic carotid cavernous sinus fistula is presented, the result of a bullet passing through both condylar regions of the mandible. The fistula was occluded by a detachable balloon brought in place using endovascular techniques.

[MRT morphology and classification of cerebral cavernomas]

An MRI review of 54 histologically verified cavernomas allowed the introduction of a system classifying this cavernous venous malformation into four types: type I (20%) corresponds to the classic morphology of a cavernoma without hemorrhage; type II (67%) is characterized by intralesional hemorrhage; type III (11%) is associated with an extra-lesional hemorrhage that compresses or displaces the cavernoma itself; and type IV (2%) corresponds to a totally calcified cavernoma. These variable cavernoma types represent different possible stages of the natural evolution of a cavernoma and limit the differential diagnosis, especially in the group of occult or cryptic cerebral vascular malformations.

[Neuroradiologic exploration of cerebral arteriovenous malformations]

MR and superselective neuroangiographic investigation of 223 patients with cerebral arteriovenous malformations (AVMs) were retrospectively analyzed with regard to topography, morphology, vascular architecture and signs of increased bleeding risk. MR proved highly efficient in defining the topography of the lesion and highly sensitive in detecting AVM-induced parenchymal changes. Superselective neuroangiography enables complete endovascular mapping of the AVM and provides relevant information on its intrinsic vascular composition. In addition, this method gives new insights into the venous drainage patterns and the unexpectedly high incidence of associated venous changes. MR-neuroangiographic correlation in each individual case forms the basis for any therapeutic decision and treatment planning. In concordance with previous statements in the literature this study disclosed that the presence of stenotic draining veins or related aneurysms on feeding arteries represents an increased risk for AVM rupture.

Neuroradiology of central neurocytoma

Central neurocytomas (CN) are rare, usually benign cerebral intraventricular neuroepithelial tumors, which occur in adult patients. Retrospective evaluation of the CT- and MRI-findings in eight cases as well as review of the cases reported in the literature showed that CN usually presents as a primarily slightly hyperdense and/or hyperintense mass within the body of the lateral ventricle with moderate contrast enhancement. The majority of tumors contain both multiple small cysts and calcifications and exhibit a characteristic broad based attachment to the superolateral ventricular wall. We conclude that these criteria appear to be reliable to exclude other intraventricular tumors such as astrocytoma, giant cell astrocytoma, ependymoma, subependymoma, intraventricular oligodendroglioma and meningioma. Preoperative diagnosis of CN may prove of value for planning therapy, because this tumor type seems to have a better prognosis than other intraventricular tumors.

[Injuries of the large brain-feeding arteries]

Among 2923 severely injured patients in the period 1980-1988, 17 had injuries or large supraaortic arteries. The incidence was 0.58%, with an overall mortality of 53%. In 75% of survivors there was a persistent neurological deficit. We treated 5 penetrating (A. carotis 4, A. vertebralis 1) and 12 nonpenetrating (A. carotis 11, A. vertebralis 1) injuries. In all penetrating carotid injuries (4) repair was performed on admission and mortality was 50%; 1 of 2 survivors has postoperative hemiparesis. Localization of nonpenetrating carotid injuries (11) was intrathoracic (2), in the neck (7) and intracranial (2). Main complication of nonpenetrating extracranial carotid injuries is neurological deficit (7/9) due to thrombosis (3) or stenosis (4) with embolism (2). Surgery was performed in 3 cases comprising pseudoaneurysm in 2 and concomitant aortic rupture in 1. Mortality was 44%, and 80% of survivors had persistent neurological deficits. Extracranial carotid injuries (n = 13) carried a mortality rate of 83% in occluded and 29% in nonoccluded vessels (p less than 0.05). Location of carotid injury in the neck (n = 11) carried a mortality of 55%, and intracranial (n = 2) of 100% respectively. Duplex-Doppler scanning of carotid arteries is a safe, noninvasive method which is essential in blunt carotid artery trauma. Prognosis is dependent upon the size of cerebral infarction. Once neurologic deficit has been established for more than 24 hours, reconstruction of the artery should be postponed and performed only for complications (pseudoaneurysm or embolization). Clamping of arteries without hypothermic circulatory arrest or shunt should be avoided. The danger of rupture in dissection and pseudoaneurysm is slight.(ABSTRACT TRUNCATED AT 250 WORDS)

Management of the internal carotid artery in surgery of the skull base

Management of the internal carotid artery in skull-base surgery can be a difficult problem when disease involves this vessel or resection is anatomically limited by it. The recent radiologic development of the detachable balloon catheter has permitted occlusion of the internal carotid artery in a controlled setting prior to any surgical procedure. An obvious prerequisite to using this technique is the demonstration of adequate collateral blood flow to the brain. Patients are evaluated with arteriography and temporary arterial balloon occlusion while monitoring physical signs and electroencephalography (EEG). Although usually performed preoperatively, internal carotid artery occlusion is needed intraoperatively on occasion. This essential adjuvant technique for the skull-base surgeon will be detailed along with its indications and limitations in 24 patients.

MRI in Cockayne syndrome type I

MRI findings are reported from two patients with Cockayne syndrome (CS) type I, aged 11 and 37 years. Changes were compatible with diffuse white matter hypomyelination. Basal ganglia calcification was present in both, marked cerebellar atrophy in the older patient. MRI may support the diagnosis of CS in the appropriate clinical context. The view that CS is a dysmyelinating disorder is further substantiated.