Intracranial hypotension may have variable clinical presentations, but has a rather uniform component of postural headache among its symptomatology. Its symptoms are explainable given the effects of the hypotension and attempts within the craniospinal axis to maintain volume homeostasis in the face of cerebrospinal fluid leakage (Monro–Kellie hypothesis). The imaging corollaries of the consequences of intracranial hypotension are especially well depicted on magnetic resonance imaging studies.
Michael Paldino, Alon Y. Mogilner and Michael S. Tenner
Thomas A. Lansen, Samuel S. Kasoff and Michael S. Tenner
✓ Periodontoid hypertrophic cicatrix resulting from trauma, as demonstrated by magnetic resonance (MR) imaging, is essentially the same as that seen in rheumatoid arthritis. Recent reports suggest that, in rheumatoid arthritis, occipitocervical fusion without transoral decompression of the pannus is adequate for resolution of this anterior lesion. A case of traumatic periodontoid cicatrix is presented in which posterior fusion resulted in reduction of the anterior mass lesion, clearly demonstrated by MR imaging. The etiology of periodontoid hypertrophic scarring, both traumatic and rheumatoid, is discussed in light of MR findings, and treatment implications are considered.
Bennett M. Stein, Michael S. Tenner and Richard A. R. Fraser
✓ Of 150 children undergoing surgery for cerebellar astrocytoma, 20% had evidence of postoperative hydrocephalus. This was manifested by either progressive symptomatic rise in intracranial pressure or abnormal mental and motor states accompanied by normal CSF pressure. This syndrome is presumed to be due to cisternal and subarachnoid adhesions formed after surgery. Prompt shunting in advanced cases resulted in reversal of neurological abnormalities.
Marga Spiller, Michael S. Tenner and William T. Couldwell
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.
Robert M. Quencer, Michael S. Tenner, Lewis M. Rothman and D. Wayne Laster
✓ Jugular venography done to evaluate abnormalities at the base of the skull demonstrated three distinctly different patterns depending on whether there is occlusion, invasion, or growth within the internal jugular vein. Improper technique results in a lack of intracranial dural sinus filling which may masquerade as venous occlusion. This problem is avoided by adequate neck compression along with proper volume and rate of delivery of contrast. Radiographically, an abnormal jugular vein at the base of the skull will show a concave defect in true occlusion, constriction or invasion of the vein by tumor, or tumor growth within the vein.
Lewis M. Rothman, Joanna Sher, Robert M. Quencer and Michael S. Tenner
✓ The authors report a unique case of ectopic intracranial pituitary adenoma, associated clinically with generalized seizures and aggressive behavior. The lesion presumably arose from cells in the pars tuberalis and did not involve the sella turcica.
James K. Liu, Michael S. Tenner, Oren N. Gottfried, Edwin A. Stevens, Joshua M. Rosenow, Neel Madan, Joel D. Macdonald, John R. W. Kestle and William T. Couldwell
Object. Cerebral vasospasm that is caused by aneurysmal subarachnoid hemorrhage and that is refractory to maximal medical management can be treated with selective intraarterial papaverine infusions. The effects of single papaverine treatments on cerebral circulation time are well known. The purpose of this study was to assess the efficacy of multiple, repeated papaverine infusions on the cerebral circulation time in patients with recurrent vasospasm.
Methods. A retrospective study was conducted in 17 patients who received multiple intraarterial papaverine infusions in 91 carotid artery (CA) territories for the treatment of cerebral vasospasm. Cerebral circulation times were measured from the first angiographic image, in which peak contrast was seen above the supraclinoid internal CA, to the peak filling of cortical veins. Glasgow Outcome Scale (GOS) scores assessed 12 months after discharge were reviewed. Cerebral circulation times in 16 CA territories were measured in a control group of 11 patients.
Seventeen patients received a total of 91 papaverine treatments. Prolonged cerebral circulation times improved after 90 (99%) of 91 papaverine treatments. The prepapaverine mean cerebral circulation time was 6.54 seconds (range 3.35–27 seconds) and the immediate postpapaverine mean cerebral circulation time was 4.19 seconds (range 2.1–12.6 seconds), an overall mean decrease of 2.35 seconds (36%, p < 0.001). Recurrent vasospasm reflected by prolonged cerebral circulation times continued to improve with subsequent papaverine infusions. Repeated infusions were just as successful quantitatively as the primary treatment (mean change 2.06 seconds). The mean cerebral circulation time in the control group was 5.21 seconds (range 4–6.8 seconds). In five patients a dramatic reversal of low-attenuation changes was detected on computerized tomography scans. The mean GOS score at 12 months after discharge was 3.4.
Conclusions. The preliminary results indicate that multiple intraarterial papaverine treatments consistently improve cerebral circulation times, even with repeated infusions in cases of recurrent vasospasm.