Perfusion- and diffusion-weighted magnetic resonance imaging for monitoring decompressive craniectomy in animals with experimental hemispheric stroke

2002 ◽  
Vol 96 (5) ◽  
pp. 933-940 ◽  
Author(s):  
Arnd Doerfler ◽  
Tobias Engelhorn ◽  
Sabine Heiland ◽  
Thomas Benner ◽  
Michael Forsting
Keyword(s):  
Basal Ganglia ◽  
Magnetic Resonance ◽  
Decompressive Craniectomy ◽  
Mr Images ◽  
Content Type ◽  
Hemispheric Stroke ◽  
Diffusion Weighted ◽  
And Diffusion ◽  
Cortical Perfusion ◽  
Fine Print

Object. The aim of this study was to use two types of serial magnetic resonance (MR) imaging—perfusionweighted (PW) and diffusion-weighted (DW)—to monitor craniectomy in rats with hemispheric stroke. Methods. Focal cerebral ischemia was induced in 36 rats by using an endovascular method of occlusion of the middle cerebral artery (MCAO). Craniectomy was performed 4 or 24 hours later in 12 animals each. Twelve control animals underwent occlusion but did not receive treatment. Perfusion-weighted, DW, and T2-weighted MR images were obtained at 4, 24, 48, 72, and 168 hours postocclusion in all animals. Relative regional cerebral blood volumes and apparent diffusion coefficients (ADCs) were calculated for the cortex and basal ganglia. Hemispheric lesion volumes (expressed as percentages of total brain volumes; %HLV) as they appeared on DW and T2-weighted MR images and on histological slices stained with 2,3,5-triphenyltetrazolium chloride were compared. Neurological performances and infarct volumes measured 7 days postocclusion were used as study end points. Both PW and DW images demonstrated ischemic tissue 4 hours after MCAO in all animals. Early treatment by performing craniectomy significantly improved cortical perfusion (p < 0.01), whereas the same procedure conveyed no benefit to the basal ganglia. Compared with findings in control animals, the DW image—derived %HLV was significantly reduced (p < 0.01) and the cortical ADCs at 4 and 24 hours postocclusion were significantly higher in animals treated early (p < 0.05). Late treatment with craniectomy did not significantly affect cerebral perfusion. The correlation between the DW imaging—derived %HLV and the histologically derived %HLV at 4 to 72 hours postocclusion was good (r = 0.74), whereas at Day 7 postocclusion the %HLV was underestimated up to 41% on DW imaging. At 4 hours postocclusion T2-weighted imaging failed to demonstrate the ischemic lesion, whereas from 24 to 72 hours postocclusion the correlation between the T2-weighted imaging—derived %HLV and the histologically derived %HLV was good (r > 0.81). Neurological performance was significantly improved in animals treated using craniectomy. Conclusions. Early craniectomy significantly improves cortical perfusion through leptomeningeal collateral vessels, significantly reduces infarct size, and improves neurological performance in animals with experimental acute hemispheric infarction. Both PW and DW imaging are suitable for noninvasive monitoring of the effects of decompressive craniectomy.

Radiosurgery performed with the aid of a 3-mm collimator in the subthalamic nucleus and substantia nigra of the vervet monkey

2001 ◽  
Vol 95 (6) ◽  
pp. 990-997 ◽  
Author(s):  
Antonio A. F. De Salles ◽  
William P. Melega ◽  
Goran Laćan ◽  
Lisa J. Steele ◽  
Timothy D. Solberg
Keyword(s):  
Basal Ganglia ◽  
Magnetic Resonance ◽  
Substantia Nigra ◽  
Subthalamic Nucleus ◽  
Vervet Monkey ◽  
Magnetic Resonance Images ◽  
Vervet Monkeys ◽  
Mr Images ◽  
Content Type ◽  
Fine Print

Object. Radiosurgery for functional neurosurgery performed using a linear accelerator (LINAC) has not been extensively characterized in preclinical studies. In the present study, the properties of a newly designed 3-mm-diameter collimator were evaluated in a dedicated LINAC, which produced lesions in the basal ganglia of vervet monkeys. Lesion formation was determined in vivo in three animals by examining magnetic resonance (MR) images to show the dosedelivery precision of targeting and the geometry and extent of the lesions. Postmortem immunohistochemical studies were conducted to determine the extent of lesion-induced radiobiological effects. Methods. In three male vervet monkeys, the subthalamic nucleus (STN; one animal) and the pars compacta of the lateral substantia nigra (SN; two animals) were targeted by a Novalis Shaped Beam Surgery System that included a 3-mm collimator and delivered a maximum dose of 150 Gy. Magnetic resonance images obtained 4, 5, and 9 months posttreatment were reviewed, and the animals were killed so that immunohistological characterizations could be made. Conclusions. The generation of precise radiosurgical lesions by a 3-mm collimator was validated in studies that targeted the basal ganglia of the vervet monkey. The extent of the lesions created in all animals remained restricted in diameter (< 3 mm) throughout the duration of the studies, as assessed by reviewing MR images. Histological studies showed that the lesions were contained within the STN and SN target areas and that there were persistent increases in glial fibrillary acidic protein immunoreactivity. Increases in immunoreactivity for tyrosine hydroxylase, the serotonin transporter, and the GluR1 subunit of the α-amino-3-hydroxy-5-methyl-4-isoxazole propionate glutamate receptor in penumbral regions of the lesion were suggestive of compensatory neuronal adaptations. This radiosurgical approach may be of particular interest for the induction of lesions of the STN and SN in studies of experimental parkinsonism, as well as for the development of potential radiosurgical treatments for Parkinson disease.

Accelerated spondylotic changes adjacent to the fused segment following central cervical corpectomy: magnetic resonance imaging study evidence

2004 ◽  
Vol 100 (1) ◽  
pp. 2-6 ◽  
Author(s):  
Vaijayantee Kulkarni ◽  
Vedantam Rajshekhar ◽  
Lakshminarayan Raghuram
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Imaging Study ◽  
Degenerative Changes ◽  
Adjacent Segment ◽  
Mr Images ◽  
Short Term ◽  
Content Type ◽  
Fine Print

Object. The authors studied whether cervical spine motion segments adjacent to a fused segment exhibit accelerated degenerative changes on short-term follow-up magnetic resonance (MR) imaging. Methods. Preoperative and short-term follow-up (mean duration 17.5 months, range 10–48 months) cervical MR images obtained in 44 patients who had undergone one- or two-level corpectomy for cervical spondylotic myelopathy were evaluated qualitatively and quantitatively. The motion segment adjacent to the fused segment and a segment remote from the fused segment were evaluated for indentation of the thecal sac, disc height, and sagittal functional diameter of the spinal canal on midsagittal T2-weighted MR images. Thecal sac indentations were classifed as mild, moderate, and severe. New indentations of the thecal sac of varying severity (mild in 17 patients [38.6%], moderate in 10 [22.7%], and severe in six [13.6%]) had developed at the adjacent segments in 33 (75%) of 44 patients. The degenerative changes were seen at the superior level in 11 patients, inferior level in 10 patients, and at both levels in 12 patients and resulted from both anterior and posterior element degeneration in the majority (23 [69.6%]) of patients. The remote segments showed mild thecal sac indentations in seven patients and moderate indentations in two patients (nine [20.5%] of 44). Compared with the changes at the remote segment, the canal size was significantly decreased at the superior adjacent segment by 0.9 mm (p = 0.007). No patient sustained a new neurological deficit due to adjacent-segment changes. Conclusions. On short-term follow-up MR imaging, levels adjacent to the fused segment exhibited more pronounced degenerative changes (compared with remote levels) in 75% of patients who had undergone one- or two-level central corpectomy.

Lack of agreement between direct magnetic resonance imaging and statistical determination of a subthalamic target: the role of electrophysiological guidance

2002 ◽  
Vol 97 (3) ◽  
pp. 591-597 ◽  
Author(s):  
Emmanuel Cuny ◽  
Dominique Guehl ◽  
Pierre Burbaud ◽  
Christian Gross ◽  
Vincent Dousset ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Functional Response ◽  
Anterior Commissure ◽  
Surgical Techniques ◽  
High Frequency Stimulation ◽  
Mr Images ◽  
Posterior Commissure ◽  
Content Type ◽  
Fine Print

Object. The goal of this study was to determine the most suitable procedure(s) to localize the optimal site for high-frequency stimulation of the subthalamic nucleus (STN) for the treatment of advanced Parkinson disease. Methods. Stereotactic coordinates of the STN were determined in 14 patients by using three different methods: direct identification of the STN on coronal and axial T2-weighted magnetic resonance (MR) images and indirect targeting in which the STN coordinates are referred to the anterior commissure—posterior commissure (AC—PC) line, which, itself, is determined either by using stereotactic ventriculography or reconstruction from three-dimensional (3D) MR images. During the surgical procedure, electrode implantation was guided by single-unit microrecordings on multiple parallel trajectories and by clinical assessment of stimulations. The site where the optimal functional response was obtained was considered to be the best target. Computerized tomography scanning was performed 3 days later and the scans were combined with preoperative 3D MR images to transfer the position of the best target to the same system of stereotactic coordinates. An algorithm was designed to convert individual stereotactic coordinates into an all-purpose PC-referenced system for comparing the respective accuracy of each method of targeting, according to the position of the best target. Conclusions. The target that is directly identified by MR imaging is more remote (mainly in the lateral axis) from the site of the optimal functional response than targets obtained using other procedures, and the variability of this method in the lateral and superoinferior axes is greater. In contrast, the target defined by 3D MR imaging is closest to the target of optimal functional response and the variability of this method is the least great. Thus, 3D reconstruction adjusted to the AC—PC line is the most accurate technique for STN targeting, whereas direct visualization of the STN on MR images is the least effective. Electrophysiological guidance makes it possible to correct the inherent inaccuracy of the imaging and surgical techniques and is not designed to modify the initial targeting.

Rathke cleft cyst intracystic nodule: a characteristic magnetic resonance imaging finding

2005 ◽  
Vol 103 (5) ◽  
pp. 837-840 ◽  
Author(s):  
Mandy J. Binning ◽  
Oren N. Gottfried ◽  
Anne G. Osborn ◽  
William T. Couldwell
Keyword(s):  
Magnetic Resonance ◽  
Signal Intensity ◽  
Imaging Finding ◽  
Magnetic Resonance Imaging Finding ◽  
High Signal ◽  
Cystic Lesions ◽  
Mr Images ◽  
Content Type ◽  
Imaging Characteristics ◽  
Fine Print

Object. The fluid content of Rathke cleft cysts (RCCs) displays variable appearances on magnetic resonance (MR) images and can appear indistinguishable from other intrasellar or suprasellar cystic lesions. Intracystic nodules associated with individual RCCs have been noted, but to date their significance has not been fully explored. Methods. The authors retrospectively reviewed MR imaging studies obtained in patients harboring intrasellar or suprasellar lesions that were consistent with RCCs to identify the presence and imaging characteristics of intracystic nodules. An intracystic nodule was present in nine (45%) of 20 patients with an RCC. All intracystic nodules were clearly visible and displayed a characteristic low signal intensity on T2-weighted MR images. The nodule was only visualized on T1-weighted images in four cases, in which it exhibited a consistent high signal intensity similar to that of the cyst fluid. The nodules did not enhance following the intravenous administration of a contrast agent. Conclusions. Although it is difficult to differentiate RCCs from other sellar cystic lesions because of the variable signal intensities displayed on MR images, the intensity of the intracystic nodule seems consistent on T1- and T2-weighted images, and the nodule is always clearly visible on T2-weighted images. With a nonenhancing cystic lesion that does not cause significant symptoms in the patient, the identification of an intracystic nodule with a characteristic signal intensity will aid in the diagnosis of RCC and the selection of conservative management.

In vivo magnetic resonance imaging of fetal cat neural tissue transplants in the adult cat spinal cord

1992 ◽  
Vol 76 (2) ◽  
pp. 261-274 ◽  
Author(s):  
Edward D. Wirth ◽  
Daniel P. Theele ◽  
Thomas H. Mareci ◽  
Douglas K. Anderson ◽  
Stacey A. Brown ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Neural Tissue ◽  
Injured Spinal Cord ◽  
Mr Images ◽  
Compression Injury ◽  
Content Type ◽  
Graft Tissue ◽  
Fine Print

✓ Magnetic resonance (MR) imaging was evaluated for its possible diagnostic application in determining the survival of fetal central nervous system tissue grafts in the injured spinal cord. Hemisection cavities were made at the T11—L1 level of eight adult female cats. Immediately thereafter, several pieces of tissue, either obtained from the fetal cat brain stem on embryonic Day 37 (E-37), from the fetal neocortex on E-37, or from the fetal spinal cord on E-23, were implanted into the cavities made in seven cats. The eighth cat served as a control for the effect of the lesion only. In another group of four animals, a static-load compression injury was made at the L-2 level. Seven weeks later, the lesion was resected in three cases and fragments of either fetal brainstem or spinal cord tissue were introduced. A small cyst was observed in a fourth cat in the compression injury group and a suspension of dissociated E-23 brain-stem cells was injected into this region of cavitation without disturbing the surrounding leptomeninges. Five months to 2 years posttransplantation, MR imaging was performed with a 2.0-tesla VIS imaging spectrometer by acquiring multislice spin-echo images (TR 1000 msec, TE 30 msec) in both the transverse and sagittal planes. Collectively, these intermediate-weighted images revealed homogeneous, slightly hyperintense signals at the graft site relative to the neighboring host tissue in seven of the 11 graft recipients. Two of the remaining four cats exhibited signals from the graft site that were approximately isointense with the adjacent host spinal cord, and the final two cats and the lesion-only control presented with very hypointense transplant/resection regions. The hyperintense and isointense images were tentatively interpreted as representing viable graft tissue, whereas the hypointense transplant/resection sites were considered to be indicative of a lack of transplant survival or the absence of tissue in the lesion-only control animal. Postmortem gross inspection of fixed specimens and light microscopy verified the MR findings in the control animal in 10 of the 11 graft recipients by showing either transplants and/or cysts corresponding to the MR images obtained. In one cat in the hemisection group, histological analysis revealed a very small piece of graft tissue that was not detected on the MR images. Therefore, it is suggested that within certain spatial- and contrast-resolution limits, MR imaging can reliably detect the presence of transplanted neural tissue in both the hemisected and compression-injured spinal cord of living animals. Thus, MR imaging can serve as an important adjunct to histological, electrophysiological, and long-term behavioral analyses of graft-mediated anatomical and functional repair of the injured spinal cord. It is further suggested that this noninvasive diagnostic approach offers many advantages in terms of the judicious and optimum use of valuable animal models, and that these findings address an important prerequisite (in situ verification of transplant survival) for any future clinical trials involving these or equivalent neural tissue grafting approaches, when such are warranted.

Effect of absorbable topical hemostatic agents on the relaxation time of blood: an in vitro study with implications for postoperative magnetic resonance imaging

2001 ◽  
Vol 95 (4) ◽  
pp. 687-693 ◽  
Author(s):  
Marga Spiller ◽  
Michael S. Tenner ◽  
William T. Couldwell
Keyword(s):  
Relaxation Time ◽  
Magnetic Resonance ◽  
In Vitro Study ◽  
Residual Tumor ◽  
Mr Images ◽  
Content Type ◽  
Hemostatic Agents ◽  
Blood Clots ◽  
Fine Print

Object. Absorbable topical hemostatic agents are commonly used in neurosurgery. In this study the authors examine the longitudinal relaxation time (T1) of blood in contact with these agents over time, measured in vitro, to determine if their presence could affect the interpretation of postoperative magnetic resonance (MR) images. Methods. Coagulated and anticoagulated blood were used, both oxygenated and deoxygenated. The effects of a collagen-based agent (Collastat) and a cellulose-based agent (Surgicel) on the pH and T1 values of blood and on those of saline (used as a control) were investigated. The T1 was measured as a function of magnetic field strength and time by using a field-cycling relaxometer. This instrument measures 1/T1, the rate of T1, from which the T1 value is computed. The T1 values of blood were compared with those of hemostat-induced blood clots and with those of both gray and white matter of the brain. Signal changes on T1-weighted MR images were predicted on the basis of altered T1 values in vitro. Postoperative images were visually examined for the predicted changes. With the addition of Surgicel, blood had decreased pH and significantly shortened T1 at all fields, essentially within minutes, although it affected the T1 of saline only minimally. The effect of Surgicel increasingly shortened the T1 for 4 days in oxygenated blood. Collastat had no significant effect. The presence of some paramagnetic methemoglobin in Surgicel-induced clots was demonstrated using the relaxometer at a time when diamagnetic oxyhemoglobin would be present in naturally occurring blood clots. A bright signal that could mimic residual tumor on contrast-enhanced images was predicted and confirmed on postoperative T1-weighted MR images obtained in patients in whom Surgicel lined the tumor bed. It was not present in cases in which Surgicel was not used. Conclusions. Surgicel alters the appearance of early postoperative MR images. To avoid misinterpretation, clinicians should be aware of this phenomenon.

Individual variations in the sulcal anatomy of the basal temporal lobe and its relevance for epilepsy surgery: an anatomical study performed using magnetic resonance imaging

2002 ◽  
Vol 96 (3) ◽  
pp. 464-473 ◽  
Author(s):  
Klaus Novak ◽  
Thomas Czech ◽  
Daniela Prayer ◽  
Wolfgang Dietrich ◽  
Wolfgang Serles ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Temporal Lobe ◽  
Anatomical Landmarks ◽  
Resonance Imaging ◽  
Mr Images ◽  
Hippocampal Region ◽  
Content Type ◽  
Individual Variations ◽  
Fine Print

Object. The concept of selective amygdalohippocampectomy is based on pathophysiological insights into the epileptogenicity of the hippocampal region and the definition of the clinical syndrome of mesial temporal lobe epilepsy (TLE). High-resolution magnetic resonance (MR) imaging allows correlation of the site of histologically conspicuous tissue with anatomical structure. The highly variable sulcal pattern of the basal temporal lobe, however, definitely complicates the morphometric analysis of histomorphologically defined subdivisions of the hippocampal region. The goal of this study was to define individual variations in the sulcal anatomy on the basis of preoperative MR images obtained in patients suffering from TLE. Methods. The authors analyzed coronal MR images obtained in 50 patients for the presence of and intrinsic relationships among the rhinal, collateral, and occipitotemporal sulci. The surface relief of consecutive sections of 100 temporal lobes was graphically outlined and the resulting maps were used for visual analysis. The sulci were characterized by measurement of their depth, distance to the temporal horn, and laterality. The anatomical measurements and frequencies of sulcal patterns were assessed for statistical correlation with patients' histories and the lateralization of the seizure focus. Conclusions. Statistical assessment shows that patient sex is a significant factor in sulcal patterns. Anatomical measurements are significantly decreased on the side of the seizure origin, which relates to loss of white matter, a known morphological abnormality associated with TLE. Magnetic resonance imaging allows for accurate preoperative knowledge of individual sulcal patterns and facilitates intraoperative orientation to anatomical landmarks.

Determining the position and size of the subthalamic nucleus based on magnetic resonance imaging results in patients with advanced Parkinson disease

2004 ◽  
Vol 100 (3) ◽  
pp. 541-546 ◽  
Author(s):  
Erich O. Richter ◽  
Tasnuva Hoque ◽  
William Halliday ◽  
Andres M. Lozano ◽  
Jean A. Saint-Cyr
Keyword(s):  
Magnetic Resonance ◽  
Parkinson Disease ◽  
Subthalamic Nucleus ◽  
Anterior Commissure ◽  
Mr Images ◽  
Posterior Commissure ◽  
Content Type ◽  
Imaging Results ◽  
Fine Print ◽  
Brain Atlases

Object. The subthalamic nucleus (STN) is a target in surgery for Parkinson disease, but its location according to brain atlases compared with its position on an individual patient's magnetic resonance (MR) images is incompletely understood. In this study both the size and location of the STN based on MR images were compared with those on the Talairach and Tournoux, and Schaltenbrand and Wahren atlases. Methods. The position of the STN relative to the midcommissural point was evaluated on 18 T2-weighted MR images (2-mm slices). Of 35 evaluable STNs, the most anterior, posterior, medial, and lateral borders were determined from axial images, dorsal and ventral borders from coronal images. These methods were validated using histological measurements in one case in which a postmortem examination was performed. The mean length of the anterior commissure—posterior commissure was 25.8 mm. Subthalamic nucleus borders derived from MR imaging were highly variable: anterior, 4.1 to −3.7 mm relative to the midcommissural point; posterior, 4.2 to 10 mm behind the midcommissural point; medial, 7.9 to 12.1 mm from the midline; lateral, 12.3 to 15.4 mm from the midline; dorsal, 0.2 to 4.2 mm below the intercommissural plane; and ventral, 5.7 to 9.9 mm below the intercommissural plane. The position of the anterior border on MR images was more posterior, and the medial border more lateral, than its position in the brain atlases. The STN was smaller on MR images compared with its size in atlases in the anteroposterior (mean 5.9 mm), mediolateral (3.7 mm), and dorsoventral (5 mm) dimensions. Conclusions. The size and position of the STN are highly variable, appearing to be smaller and situated more posterior and lateral on MR images than in atlases. Care must be taken in relying on coordinates relative to the commissures for targeting of the STN.

Extracerebral fluid collections in infancy: role of magnetic resonance imaging in differentiation between subdural effusion and subarachnoid space enlargement

1994 ◽  
Vol 81 (1) ◽  
pp. 20-23 ◽  
Author(s):  
Nobuhiko Aoki
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Subdural Effusion ◽  
Mr Images ◽  
Content Type ◽  
Vascular Flow ◽  
Flow Void ◽  
Subarachnoid Spaces ◽  
Fluid Collections ◽  
Fine Print

✓ The pathological process of extracerebral fluid collections in infancy includes subdural effusion and enlargement of the subarachnoid spaces. Both conditions have traditionally been investigated as a single clinical entity, because of difficulty in differentiating between them. The prognosis of subdural effusion is not as benign as that of enlargement of subarachnoid spaces, requiring differential diagnosis between these disorders. The present study was conducted to elucidate whether this differentiation could be made on magnetic resonance (MR) images. The series consisted of 16 infants aged 10 months or younger, including eight with verified subdural effusion and eight in whom a diagnosis of enlargement of the subarachnoid spaces was achieved by neuroimaging studies other than MR imaging. In all eight patients with subdural effusion, the intensity of the fluid was greater than that of cerebrospinal fluid (CSF) in at least one of the sequences using T1-weighted, proton-density, and T2-weighted MR images. The flow-void sign, indicating vessels in the fluid spaces, was not seen in any of these eight patients. On the other hand, in all eight patients with enlargement of the subarachnoid spaces, the fluid was isointense in relation to CSF, and vascular flow-void areas were seen in at least one of the MR imaging sequences. Based on these observations, it is concluded that differentiation between subdural effusion and enlargement of the subarachnoid spaces can be established by focusing on two aspects of MR imaging findings: 1) the intensity of the fluid, which is either iso- or hyperintense relative to CSF, and 2) the presence or absence of vascular flow-void areas in the fluid spaces.

Association between a black band on the inner membrane of a chronic subdural hematoma on T2*-weighted magnetic resonance images and enlargement of the hematoma

2003 ◽  
Vol 99 (5) ◽  
pp. 824-830 ◽  
Author(s):  
Toshio Imaizumi ◽  
Yoshifumi Horita ◽  
Toshimi Honma ◽  
Jun Niwa
Keyword(s):  
Surgical Treatment ◽  
Magnetic Resonance ◽  
Chronic Subdural Hematoma ◽  
Magnetic Resonance Images ◽  
Mr Images ◽  
Inner Membrane ◽  
Content Type ◽  
Black Band ◽  
Fine Print

Object. The cause and indication for enlargement of chronic subdural hematomas (CSDHs) have remained unresolved. The authors observed a black band on the inner membrane of a CSDH on T2*-weighted magnetic resonance (MR) images obtained in patients with symptoms. After surgical treatment, the band disappeared. The T2*-weighted sequence of MR imaging is an excellent diagnostic tool for detecting ferromagnetic substances, but it is rarely performed in cases of a CSDH. The authors speculate that the black band may be associated with the development of CSDH. Methods. To investigate how the black band observed on T2*-weighted MR images contributes to the development of a CSDH, 59 lesions in 50 patients with CSDH (41 men and nine women, mean age 70 ± 11 years [range 48–93 years]) were investigated prospectively. The incidence of black bands on the first T2*-weighted MR image obtained in patients with symptomatic CSDH was 97% (31 of 32 CSDHs), which was significantly higher than that associated with asymptomatic CSDH (11% [three of 27 CSDHs], p < 0.001). The black bands associated with symptomatic CSDH disappeared soon after surgical treatment in 31 CSDHs and became fainter in another. In two instances the CSDH recurred with reappearance of the band. Twenty-four of 27 asymptomatic CSDHs had no accompanying black band. Follow-up MR images demonstrated a later formation of bands in two of 24 asymptomatic CSDHs that enlarged to symptomatic size. Logistic regression analysis revealed that the heterogeneity and thickness of the CSDH on computerized tomography scans were independently and significantly associated with the black band. Conclusions. The dynamics of the black band may depend on the enlargement or shrinkage of the CSDH.

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