Wavelet assessment of cerebrospinal compensatory reserve and cerebrovascular reactivity

We introduce a wavelet transfer model to relate spontaneous arterial blood pressure (ABP) fluctuations to intracranial pressure (ICP) fluctuations. We employ a complex continuous wavelet transform to develop a consistent mathematical framework capable of parametrizing both cerebral compensatory reserve and cerebrovascular reactivity. The frequency-dependent gain and phase of the wavelet transfer function are introduced because of the non-stationary character of the ICP and ABP time series. The gain characterizes the dampening of spontaneous ABP fluctuations and is interpreted as a novel measure of cerebrospinal compensatory reserve. For a group of 12 patients who died as a result of cerebral lesions (Glasgow Outcome Scale (GOS) = 1) the average gain in the low-frequency (0.02- 0.07 Hz) range was 0.51 +/- 0.13 and significantly exceeded that of 17 patients with GOS = 2 having an average gain of 0.26 +/- 0.11 with p = 1x10(-4) (Kruskal-Wallis test). A time-averaged synchronization index (which may vary from 0 to 1) defined in terms of the wavelet transfer function phase yields information about the stability of the phase difference of the ABP and ICP signals and is used as a cerebrovascular reactivity index. A low value of synchronization index reflects a normally reactive vascular bed, while a high value indicates pathological entrainment of ABP and ICP fluctuations. Such entrainment is strongly pronounced in patients with fatal outcome (for this group the low-frequency synchronization index was 0.69 +/- 0.17). The gain and synchronization parameters define a cerebral hemodynamic state space (CHS) in which the patients with GOS = 1 are to large extent partitioned away from those with GOS = 2. The concept of CHS elucidates the interplay of vascular and compensatory mechanisms.

The influence of ruptured cerebral aneurysm localization on the blood flow velocity evaluated by transcranial Doppler ultrasonography

The relationship between changes of blood flow velocities in cerebral arteries measured by transcranial Doppler ultrasonography and aneurysm localization was investigated in a group of 165 patients after aneurysmal subarachnoid hemorrhage (SAH). Mean blood flow velocities (MFV) in the middle cerebral artery (MCA) and anterior cerebral artery (ACA) were registered. In patients with aneurysm of internal carotid artery and MCA (group A) statistically significant higher values of MFV from the 1st to the 5th day and on the 12th, 13th, 14th, 15th, and 19th day after SAH were found compared to patients with aneurysm of the anterior communicating artery, ACA, and pericallosal artery (group B). Pathological values of MFV exceeding 120 cm sec-1 in MCA were registered during 14 days in group A and during eight days in group B. Blood flow velocities in ACA were statistically significantly higher in group B on the 2nd, 7th, 9th and 11th day compared to group A. Pathological values of MFV exceeding 90 cm sec-1 in ACA were registered during nine days in both groups. MFV differences between group A and group B in 38 patients subjected to delayed surgery were not observed. The influence of aneurysm localization was observed between the 7th and 14th day after SAH. Critical MFV values for vasospasm in the MCA should be 120 cm sec-1 and in the ACA 90 cm sec-1.

The relationship between cerebral blood flow velocities and the amount of blood clots in computed tomography after subarachnoid haemorrhage

127 patients with aneurysmal subarachnoid haemorrhage (SAH) were analyzed for the relationship between the amount of blood clots as detected by initial computed tomography (CT) up to 48 hours after SAH and changes of blood flow velocities as measured using transcranial Doppler ultrasonography (TCD). All patients were operated on within 72 hours after SAH. Patients who presented with remarkable brain oedema or with pathological intracranial pressure (ICP) due to mass effects of a haematoma, and who were in a poor neurological condition classified according to Hunt-Hess as grade V were excluded from this study. Serial TCD examination of the middle cerebral arteries (MCA) and anterior cerebral arteries (ACA) started within 48 hours after SAH and were performed daily up to three weeks. A statistically significant correlation between blood load designated according to Fisher's grading as group CT I-CT IV and mean flow velocities (MFV) was found in groups CT I, II, and III. High values of MFV in MCA examinations were noted in patients with severe SAH (group CT III)--161 cm/s, and low values in patients without SAH (group CT I)--119 cm/s. Patients with haematocephalus and/or haematoma without a mass effect (group CT IV) had lower blood flow velocities than patients with severe SAH (group CT III) but values were higher than in patients without SAH (group CT I). The number of days for which MFV in the MCA was > 120 cm/s and was statistically (p < 0.05) correlated with the amount of blood clots as observed in the respective CT (in group CT I, II, and III). MFV values in the anterior cerebral artery (ACA) were lower than those obtained in the middle cerebral artery (MCA) in all groups. Statistically significant (p < 0.05) differences were noted between groups CT I and CT III (first and third week) and between groups CT I and CT IV (third week). If the SAH was extensive in the CT scan, pathological values of MFV > 90 cm/s were observed in ACA, and this was more pronounced in group CT III than in group CT IV. Blood flow velocities obtained via TCD were registered to compare side-to-side differences and particularly high differences were observed in patients with severe SAH. It is concluded that the amount of blood clots in the initial computed tomography after SAH is significantly correlated with cerebral blood flow velocity measurements by TCD.

Multiple metastases of carcinoma basocellulare into spinal column

Basal cell carcinoma presents a relatively low potential and local malignancy and very slow growth giving only occasionally metastatic spreading. The frequency of occurrence of metastatic dissemination is estimated in the literature depending on examined population from 0.028% to 0.55%. Metastases are most often found in lymph nodes, lungs bones and internal organs: liver, spleen, kidneys, adrenal glands, pleura and the peritoneum. Authors present a case of a 69-years old female with an extensive basal cell carcinoma of the head convexity, infiltrating the subcutaneous tissue, periostium, bone and dura mater, giving distant metastases to other bone and soft tissue structures of a thoracic spine, which was confirmed by biopsy and histopathological findings of neoplasm tissue in spine. The primary lesion was successfully treated surgically. Despite administered radiotherapy of metastases in spine, progress of the disease during 1-year period was observed. The patient was alive with metastatic tumours present at last follow-up. Basing on the review of the literature and our case report we can distinguish following factors which may increase the risk of occurrence of basal cell carcinoma metastases: the great extent of the primary lesion, deep penetration to stromal tissue, blood and lymph vessel invasion, long history of tumour occurrence and the presence of metatypia in histopathological findings. The above-mentioned case fulfils the criteria of carcinoma basocellulare metastases proposed by Latters and Kessel and may be included to the general registration list of this cancer in the world.

[Infusion test in the selection of patients with hydrocephalus for the shunting]

The indications for the shunting of the patients with NPH are a matter of discussion. The measurement of the outflow resistance during the infusion test is one of the criteria for shunting. The authors present 38 patients with NPH in whom the lumbar constant-infusion test was carried out. The patients with the outflow resistance more then 13 mmHg/ml/min were selected for shunting. The results at least 4 months after operation are presented.

[The application of transcranial doppler sonography in the evaluation of cerebral flow disturbances after head trauma]

Several types of cerebral blood flow disturbances, resulting from head trauma are discussed. Application of Transcranial Doppler Sonography in diagnosing of posttraumatic cerebral vasospasm and cerebral hyperaemia, increased intracranial pressure, autoregulation disturbances, and brain death is described. Clinical examples of isolated cerebral blood flow disturbances, and several types of their co-existence are given. Special attention was paid to the noninvasiveness, repetitiveness, and relative ease of use of the technique. Transcranial Doppler examination can be especially useful in diagnosis and monitoring of different cerebral blood flow disturbances, which is especially important in therapy of brain trauma patients.