Spontaneous intracranial hypotension: case report with subdural hematomas, steroid dependency and clinical improvement after myelography.

OBJECTIVE: In spontaneous intracranial hypotension (SIH), also known as spontaneous hypoliquorrhea, an abnormally low intracranial pressure leads to posture-dependent headaches similar to those observed after lumbar puncture. Although its etiology is not yet fully understood, it is now diagnosed more often as clinical awareness increases and the availability of MRI becomes more widespread. CLINICAL PRESENTATION: We report the case of a 42-year-old patient with SIH who developed bilateral subdural hematomas (SDH) and symptomatic diencephalic herniation requiring surgical evacuation. Remarkably, he also developed partial pituitary insufficiency. THERAPY: After SDH was evacuated twice without success, his symptoms resolved rapidly after a diagnostic myelography. CONCLUSION: Besides the orthostatic headache, the possible clinical manifestations are numerous. Serious complications and situations may occur that need to be recognized and treated. In addition to presentation of the case the literature to date is reviewed and discussed.

New ultrasound techniques and their application in neurosurgical intra-operative sonography.

We describe a variety of new ultrasound techniques by their physical background, potentials and applications regarding usefulness during intra-operative neurosurgical procedures. Transducers like high-frequency and small rotating probes fitting into neuroendoscopes, imaging techniques as extended field-of-view technique, harmonic imaging, echo-enhancers, 3-D imaging and the real-time integration of neurosonography with pre-operative CT- or MR-data are mentioned. The technical or physical principles are explained, followed by a discussion of these techniques from available literature dealing with their intra-operative neurosurgical applications and the experience of the authors with the techniques. With higher frequencies micromillimeter imaging is possible and small probe allows endoneurosonography. Echo-enhancers and harmonic imaging improve the signal-to-noise ratio and 3-D imaging and extended field-of-view techniques allows a better understanding of the pathoanatomy. With the real-time integration of intra-operative ultrasound images and pre-operative CT or MR images additional information, like hemodynamic pattern, are available for the neurosurgeon. Although until now only a limited number of reports about new sonographic techniques during intra-operative application in neurosurgery exist, the methods seem to be promising in creating images easier to understand, incorporating more information about pathoanatomy and supplying the neurosurgeon with information additional to that provided by CT and MRI.

Ultrasound-guided neuronavigation of deep-seated cavernous haemangiomas: clinical results and navigation techniques.

The aim of this study was to evaluate guidance techniques and patient outcomes of ultrasound-guided neuronavigation of deep-seated intracerebral cavernous hemangiomas (CAs). Thirty-five patients with deep-seated intracerebral CAs with sizes ranging between 7 and 45 mm were operated upon only with ultrasound-guidance. Twenty-seven were located in or near eloquent regions. In 30 patients dissection to the lesion was performed through sulci and fissures. The best approach to a lesion based on surface anatomy and depth was determined using sonographic information. Navigation was done sonographically. In five patients the shortest approach via a corticotomy was determined sonographically. Twenty-six patients had no neurological deficit postoperatively. Preoperative deficits improved in seven of nine patients. Fifteen of 19 patients suffering epileptic seizures had no seizures postoperatively. Intraoperative sonography revealed residual CA tissue after microsurgical extirpation in two cases. This report shows that intraoperative sonographic navigation provides safe guidance to deep-seated CAs with good clinical outcome independent of size.

Early postoperative transcranial sonography (TCS), CT, and MRI after resection of high grade glioma: evaluation of residual tumour and its influence on prognosis.

PURPOSE: In this prospective study the results of multimodal postoperative neuro-imaging were related to the survival of patients with high grade gliomas. METHODS: All 73 patients included underwent microsurgical tumour resection and had postoperative CT and transcranial sonography (TCS) examinations. In addition, 35 of the 73 patients received an early postoperative MRI. Patients were followed up for at least one year. FINDINGS: At the end of the 7 year study period 56 patients had died. The median survival time was 371 days. Survival rate was significantly higher in patients with anaplastic astrocytomas and inpatients displaying complete tumour resection on MRI (log-rank-test, p < 0.05) or a small postoperative residual tumour bulk on TCS (log-rank-test, p < 0.05). Cox proportional hazards model identified histological tumour grade, postoperative Karnofsky index, complete resection based on MRI and small postoperative residual tumour mass on TCS as independent predictors of survival. INTERPRETATION: This study demonstrates that early postoperative neuro-imaging has prognostic implications for the survival of patients with high grade gliomas. According to our results postoperative imaging with MRI and TCS is a valuable prognostic with regard to patient survival and should therefore be implemented in postoperative follow-up. It also helps to evaluate the efficacy of adjuvant therapy.

Localization and characterization of intracerebral cavernous angiomas by intra-operative high-resolution colour-duplex-sonography.

The aim of this prospective study was to evaluate the reliability of high-resolution Colour-Duplex-Sonography (= CDS) in intra-operative localization, guiding and characterization of intracerebral cavernous angiomas (= CA). During a time period from 5/93 to 12/96 a total of 26 patients with 21 supratentorial and 5 infratentorial CA (15 of them deep-seated) were examined intra-operatively by CDS. The study focussed on 1. sonographic characterization, 2. localization in relationship to anatomical landmarks, 3. navigation, 4. correlation of sonographic to magnetic resonance imaging (= MRI), intra-arterial angiography (= DSA) and histological results and 5. control of complete resection. All CA appeared sonographically as hyperechoic lesions without flow-signals in Colour-mode. Imaging of anatomical landmarks as cerebral sulci, brain stem, insular cistern, falx, ventricles and vessels could be used for precise localization and successful guiding to 15 deep-seated lesions. The correlation of the size between MRI and CDS was excellent (1.4 mm mean difference, range from 0 to 5 mm). All 4 associated venous anomalies, as verified by pre-operative DSA, could be visualized and identified by CDS. The completeness of exstirpation was controlled sonographically in 14 cases and confirmed by MRI (= 10) and CT (= 4). This study provides the first comprehensive intra-operative characterization of CAs by CDS and correlation to MRI and DSA. Furthermore it demonstrates the reliability of CDS for intra-operative localization and guiding as well as its potential to control the complete exstirpation.

Primary intracerebral Hodgkin's disease: report of a case with Epstein-Barr virus association and review of the literature.

A case of primary intracerebral Hodgkin's disease (HD) without dural attachment in a 54-year-old immunocompetent patient is described. The infiltrate was located superficially in the occipital lobe and corresponded to the histologic type of nodular sclerosis. A typical immunohistochemical profile (membrane and cytoplasmic staining with dotlike Golgi enhancement of CD30, moderate cytoplasmic staining of CD15 in the Golgi area, membrane staining of CD20 of <10% of blastic cells, CD45RB negative) and in addition Epstein-Barr virus (EBV) latent membrane protein was detectable in Reed-Sternberg cells. Staging revealed no other organ sites of involvement. After combined surgery, postoperative radiotherapy, and chemotherapy, there are no signs of recurrence or systemic disease on follow-up for >1 year. To the authors' best knowledge, an association of EBV with primary central nervous system HD has not been demonstrated before.

Postoperative neuroimaging of high-grade gliomas: comparison of transcranial sonography, magnetic resonance imaging, and computed tomography.

BACKGROUND: A precise and comprehensive knowledge of tumor burden and its extent and growth pattern in the pre- and postsurgical states is required to optimize tumor therapy and to determine treatment success and failure. This prospective study compares the diagnostic potential of computed tomography (CT), magnetic resonance imaging (MRI), and transcranial sonography (TCS) in the postoperative follow-up of brain tumors. METHOD: Twenty-six patients with high-grade gliomas were included in the study. After tumor debulking, a total of 31 biopsy specimens were obtained from the resection margin in 21 patients and histological findings were compared with the findings of early postoperative TCS, CT, and MRI. Findings indicating residual tumor tissue were nonlinear contrast enhancement at the resection site revealed by CT or MRI or hyperechogenic lesions revealed by TCS. Follow-up examinations using all three imaging techniques were performed every 3 months. The end points of the follow-up were tumor recurrence as defined by CT and MRI, death, or severe clinical deterioration. RESULTS: On the basis of the above criteria, TCS identified residual tumor more often than did CT or MRI. In the group of 19 patients with histologically proven tumor remnants, residual tumor tissue was identified by TCS in all patients, whereas MRI and CT failed to show contrast enhancement in three and eight patients, respectively. However, the results of the TCS were false positive for one patient because of hemorrhage into the resection site. The average time to identification of tumor regrowth was 27 weeks using TCS, 29 weeks using CT, and 33 weeks using MRI. Only the differences between TCS and MRI reached statistical significance. For one patient, multicentric tumor recurrence was not detected using TCS. CONCLUSION: TCS may complement CT and MRI in the postoperative follow-up of patients with high-grade gliomas. Because none of these modalities alone is both sensitive and specific, an integrated analysis of imaging findings is recommended.

Differentiation between intracerebral hemorrhage and ischemic stroke by transcranial color-coded duplex-sonography.

BACKGROUND AND PURPOSE: The differential diagnosis of intracerebral hemorrhage versus ischemic stroke has critical implications for stroke management. Transcranial color-coded duplex sonography (TCCS) has been shown to identify intracerebral hemorrhages and intracerebral vessel occlusions. We conducted this study to evaluate the sensitivity and specificity of TCCS in this differential diagnosis and in the detection of stroke complications. METHODS: One hundred fifty-one patients (58 women, 93 men; mean age, 65.6 years [range, 32 to 89 years] ) with acute hemiparesis were enrolled in this prospective study. On admission all patients had a complete neurological examination. A cranial CT scan and a sonographic examination of the brain parenchyma and all extracranial and intracranial cerebral arteries were conducted. The sonographer was blinded for the radiological findings. RESULTS: According to CT criteria, 60 patients had an intracerebral hemorrhage and 67 patients had an ischemic stroke, and in 24 patients CT findings were inconclusive, showing neither bleeding nor an ischemic stroke. On sonographic examination, 18 patients (12%) had no sufficient acoustic bone window. Of the remaining 133 patients, 126 (95%) were diagnosed correctly by sonography in agreement with CT. Sonography missed 3 atypical bleedings (2 with upper parietal location). In 4 patients without bleeding, an intracerebral hemorrhage was suspected by TCCS because of increased white matter echo density due to microangiopathy. Stroke complications depicted by CT (disturbance of cerebrospinal fluid circulation, hemorrhagic transformation, midline shift, ventricular bleeding) (n=54) were correctly shown by TCCS in 45 patients (83%). No complication was missed that would have required further treatment. CONCLUSIONS: In comparison to the "gold standard" of CT, TCCS identified stroke complications and differentiated between intracerebral hemorrhage and ischemic stroke with reasonable sensitivity. Thus, if CT is not readily available, TCCS may complement clinical examination in patients with acute stroke. In addition, it may also be useful in detecting stroke complications in the follow-up of stroke patients.

Intra-operative colour-duplex-sonography in the surgical management of cerebral AV-malformations.

In this prospective study the role of intra-operative Colour-Duplex-Sonography (= CDS) during surgery of arteriovenous malformations (= AVM) is evaluated. During the last three years 20 consecutive patients with supratentorial AVMs were examined by intra-operative CDS in order to evaluate the potential of CDS to 1) localize the AVM, 2) differentiate between embolized and perfused parts, 3) identify feeding and draining vessels and 4) control the complete excision of the AVM. All AVMs were localized supratentorially, 9 were grade I and II (according to Spetzler and Martin [31]), 8 grade III and 3 grade IV. 11 were partly embolized and 8 associated with an intracerebral bleeding. In all cases the nidus was correctly localized sonographically by its typical bidirectional flow pattern in Colour-mode. CDS guided the surgeon directly to all (11 cases) deep-seated AVMs (2 to 4 cm subcortically). The smallest nidus measured 10 mm. 28 of 34 angiographically defined main feeding and 18 of 23 draining vessels were identified. 14 patients were controlled sonographically at the end of the resection regarding the completeness of excision. In 11 patients CDS was negative and was confirmed by either postoperative angiography or MRI in 10 patients. In one case residual AVM tissue was missed by CDS. Positive CDS findings in 3 cases were all confirmed by microscopic re-inspection, angiography and CCT. Our results suggest that CDS is able to localize AVMs intra-operatively with minimal instrumentation. It allows safe navigation to deep-seated malformations with high accuracy. Feeding and draining vessels can be identified and completeness of resection can be controlled.

Intraoperative color duplex sonography of basal arteries during aneurysm surgery.

This prospective study aimed at (1) characterizing the duplex sonographic appearance of cerebral aneurysms, (2) visualizing their location, and (3) ensuring the complete occlusion of the aneurysm as well as the patency of the basal arteries during aneurysm surgery. During 9 months 30 craniotomies for aneurysm clipping in 29 patients were monitored intraoperatively by B-mode and color-coded duplex sonography. Following craniotomy the aneurysm and the preaneurysmatic and postaneurysmatic arteries were sonographically visualized before and after clipping and removal of the spatulas. Twenty-seven (90%) of 30 aneurysms appeared as a hypoechoic structure. Together with the typical dichromatic picture in the color mode and the characteristic bidirectional flow pattern in the duplex mode, 29 (97%) of 30 aneurysms were identified and localized anatomically correctly. Eighty (99%) of 81 relevant vessels were visualized and measured with the Doppler mode. After clipping, flow was detectable in all major arteries except 3 middle cerebral artery (MCA) branches. In 1, occlusion was confirmed by postoperative angiography. In the other 2, early postoperative computed tomography showed an infarction of the corresponding MCA territories. This study demonstrated the potential of color duplex sonography to visualize and characterize cerebral aneurysms and adjacent basal arteries before and after clipping. It offers a noninvasive intraoperative method to control the patency of basal arteries and complete occlusion of the aneurysm.

Transcranial duplex-sonography in intracranial hemorrhage. Evaluation of transcranial duplex-sonography in the diagnosis of spontaneous and traumatic intracranial hemorrhage.

The aim of this prospective clinical study was to evaluate the potential of bedside transcranial color-coded duplex sonography (TDS) in the assessment of patients with acute intracranial hemorrhage and respective complications. 74 patients (35 with spontaneous and 27 with traumatic hemorrhage, 12 excluded due to insufficient insonability) underwent 152 TDS examinations. The results were compared to computer-tomography (CT) as well as conventional transcranial Doppler sonography (TcD). The size and localisation of intracerebral hemorrhages as detected in TDS coincided in 39/42 examinations with CT findings; in cases of traumatic intracranial extracerebral hematoma TDS correlated in all but one case (18/19). The TDS findings for the diameter of third and lateral ventricles (n = 126) as for midline-shift (n = 26) showed a good correlation (p < 0.0005) to CT-measurements. TDS appears to be a useful bedside, non-invasive tool in order to detect and exclude intracranial complications in patients with intracranial hemorrhages.

Correlation of intra-operative ultrasound with histopathologic findings after tumour resection in supratentorial gliomas. A method to improve gross total tumour resection.

The aim of this study was to evaluate whether intra-operative ultrasound (= IOUS) is a suitable tool to detect residual tumour tissue after gross total resection in supratentorial gliomas. During a period of 18 months 45 patients with supratentorial gliomas (38 high-grade and 9 low-grade, according to the WHO-grading system [42]) were operated on. A series of 78 biopsies was taken from the resection cavity under continuous sonographic control at the end of surgery. Gross total tumour resection was intended in 34 patients (= 76%). The biopsy specimens were matched with the sonographic features at each biopsy site. The sonographic appearance of the resection margins were classified into 2 groups: (1) Irregular hyperechoic areas extending from the cavity into the iso-echogenic brain tissue and (2) a dense small (< or = 3 mm in diameter) rather regular hyperechoic rim surrounding the resection cavity. 47 out of 53 biopsies taken from hyperechoic areas (group I) (36 high-grade/11 low-grade) revealed solid tumour tissue (= 89%). 34 (= 72%) of these 47 areas were microscopically assessed as inconspicuous by the surgeon. 6 samples (4 high-grade/2 low-grade) contained tumour infiltration zone. 25 biopsies (23 high-grade/2 low-grade) taken from the hyperechoic rim [group 2] were diagnosed as follows: Normal brain tissue in 11, tumour infiltration zone in 8 and solid tumour tissue in 6 cases. Of 34 cases with "gross total removal" according to the surgeon's assessment 25 showed sonographic signs of residual tumour tissue, which was confirmed histologically as solid tumour tissue in 22 of these cases. It is concluded, that IOUS following resection of supratentorial gliomas can detect residual tumour tissue with high specificity and thus improve gross total resection. However, a thin hyperechoic rim surrounding the resection cavity (less than 3 mm in diameter) is a non-specific finding, which can mask thin residual tumour layers and therefore needs further evaluation of its nature.

Preoperative and postoperative follow-up in high-grade gliomas: comparison of transcranial color-coded real-time sonography and computed tomography findings.

Twenty patients with high-grade gliomas were prospectively studied by pre- and postoperative transcranial color-coded real-time sonography (TCCS) and CT, to determine the sensitivity of TCCS in the identification of residual tumor and tumor regrowth. Each patient was subjected to preoperative and early postoperative CT (postoperative day 1) and TCCS examinations (postoperative days 6 to 8) and subsequent CT and TCCS follow-up examinations within a time interval of 6 weeks to 3 months. In eight patients, a total of 15 biopsy specimens were intraoperatively obtained from the wall of the resection cavity. Histological findings of intraoperative biopsy specimens showed that hyperechogenic areas adjacent to the resection cavity always contained residual tumor tissue. Early postoperative TCCS identified these hyperechogenic areas in 19 of 20 patients. In 12 patients, postoperative CT revealed contrast enhancement at the resection margin, indicating residual tumor. In these patients the extension of these hyperechogenic areas on TCCS exceeded the contrast-enhancing areas on CT by a mean of 58%. In eight patients, postoperative CT displayed no contrast enhancement along the border of resection. TCCS and histological findings indicated residual tumor in seven of these eight patients. The size of the hyperechogenic lesions identified by postoperative TCCS increased in time and follow-up examinations revealed that tumor regrowth arose from these hyperechogenic areas in all patients. In four patients, tumor regrowth was identified, on average 0.7 months earlier by TCCS than by CT. From these data we conclude that the sensitivity of TCCS in detection of residual tumor and tumor regrowth seems to be superior to CT. The value of TCCS requires further clarification by comparative studies including histology and MRI.