Isolated dissections and dissecting aneurysms of the posterior inferior cerebellar artery: topic and literature review

Isolated dissections of the posterior inferior cerebellar artery (PICA) are rare. Thus, no large series of cases have been reported in the literature. Due to limited knowledge regarding the natural history of these lesions and the lack of high-quality evidence supporting various treatment options, management is controversial and practice parameters are ill defined. In order to offer a comprehensive reference for the diagnosis and management of isolated PICA dissections, the authors reviewed the National Library of Medicine from 1966 to October 2001. Twenty-seven patients averaging 43.6 years of age and including 14 males and 13 females were reported. Subarachnoid hemorrhage occurred in 20 patients, and two died. Dissections were located in the proximal PICA in 22 patients and were three times more common on the left side (left:right=3:1). Six patients were managed conservatively, and four with endovascular techniques. Seventeen had open surgery: five underwent resection, two went through trapping, and two had proximal clipping. Wrapping with muscle was performed in two patients, encasement with Sundt clips in two, and four had occipital artery (OA)-PICA bypass surgery. A meticulous analysis of reported cases with regard to clinical and pathological features, management strategies, and outcomes is presented.

Radiation doses in interventional radiology procedures: the RAD-IR study: part I: overall measures of dose

PURPOSE

To determine patient radiation doses for interventional radiology and neuroradiology procedures, to identify procedures associated with higher radiation doses, and to determine the effects of various parameters on patient doses.

MATERIALS AND METHODS

A prospective observational study was performed at seven academic medical centers. Each site contributed demographic and radiation dose data for subjects undergoing specific procedures in fluoroscopic suites equipped with built-in cumulative dose (CD) and dose-area-product (DAP) measurement capability compliant with International Electrotechnical Commission standard 60601-2-43. The accuracy of the dosimetry was confirmed by comprehensive measurements and by frequent consistency checks performed over the course of the study.

RESULTS

Data were collected on 2,142 instances of interventional radiology procedures, 48 comprehensive physics evaluations, and 581 periodic consistency checks from the 12 fluoroscopic units in the study. There were wide variations in dose and statistically significant differences in fluoroscopy time, number of images, DAP, and CD for different instances of the same procedure, depending on the nature of the lesion, its anatomic location, and the complexity of the procedure. For the 2,142 instances, observed CD and DAP correlate well overall (r = 0.83, P <.000001), but correlation in individual instances is poor. The same is true for the correlation between fluoroscopy time and CD (r = 0.79, P <.000001). The correlation between fluoroscopy time and DAP (r = 0.60, P <.000001) is not as good. In 6% of instances (128 of 2,142), which were principally embolization procedures, transjugular intrahepatic portosystemic shunt (TIPS) procedures, and renal/visceral artery stent placements, CD was greater than 5 Gy.

CONCLUSIONS

Most procedures studied can result in clinically significant radiation dose to the patient, even when performed by trained operators with use of dose-reducing technology and modern fluoroscopic equipment. Embolization procedures, TIPS creation, and renal/visceral artery stent placement are associated with a substantial likelihood of clinically significant patient dose. At minimum, patient dose data should be recorded in the medical record for these three types of procedures. These data should include indicators of the risk of deterministic effects as well as the risk of stochastic effects.

Myelographic MR imaging of the cervical spine with a 3D true fast imaging with steady-state precession technique: initial experience

The majority of spinal magnetic resonance (MR) imaging has been performed with spin-echo sequences and spoiled gradient-echo sequences. Advances in gradient MR imaging performance now permit imaging with coherent steady-state sequences. In this study, the authors compare a three-dimensional true fast imaging with steady-state precession sequence with a three-dimensional spoiled gradient-recalled-echo sequence for MR evaluation of the cervical spine in the transverse plane. Initial experience indicates that the steady-state sequence is superior to spoiled gradient-recalled-echo sequences for MR evaluation of cervical spine anatomy and abnormalities.

Superior sagittal sinus thrombosis in a patient with postdural puncture headache

BACKGROUND AND OBJECTIVES

The occurrence of concomitant intracranial pathology in a patient with postdural puncture headache (PDPH) is rare. We present a patient who had a superior sagittal sinus thrombosis in addition to his PDPH. The signs and symptoms of intracranial pathology in patients with dural puncture headache, in addition to their postural headache, are discussed.

CASE REPORT

A 32-year-old man with lymphoblastic lymphoma received treatment with daunorubicin, vincristine, and prednisone. He developed postural headache and severe nausea and vomiting after a diagnostic lumbar puncture. Magnetic resonance imaging (MRI) showed superior sagittal sinus (SSS) thrombosis and meningeal enhancement. An epidural blood patch was performed and enoxaparin was prescribed for 6 months. He has remained asymptomatic.

CONCLUSIONS

Patients with PDPH have classic postural headache. The occurrence of additional signs and symptoms should alert the clinician to the presence of intracranial pathology. Patients with lymphoblastic lymphoma who had treatment with L-asparaginase and steroid are predisposed to the development of cortical venous thrombosis and may have this syndrome in addition to a dural puncture headache.

Coiling of cerebral aneurysm remnants after clipping

OBJECTIVE

During the past decade, options for the management of aneurysm remnants after clipping have expanded. Advances in aneurysm coiling techniques and technology have allowed for more remnants to be treated safely. We present our experience with this approach and discuss its indications, limitations, and results.

METHODS

We retrospectively reviewed the Northwestern Memorial Hospital experience with aneurysm coiling between January 1996 and June 2001. We identified five patients who underwent coiling for aneurysm remnants after clipping. We reviewed the clinical history, all follow-up notes, and all relevant imaging studies. We also reviewed MEDLINE for all articles published in the English language between 1990 and September 2001 that included patients treated with this approach.

RESULTS

Complete to near-complete aneurysm occlusion was achieved in all five patients in our study. There was no permanent morbidity or mortality associated with the procedure in any of these patients. In the literature, we found seven articles that discuss 21 patients who were treated with coiling for their remnants. There were no permanent complications reported for these 21 patients. Adequate long-term follow-up in these 21 patients, however, is lacking.

CONCLUSION

Complete aneurysm occlusion is the goal of aneurysm clipping. When this goal cannot be achieved safely, coiling of the remnant, if size and morphology are amenable, is a safe option that should be considered. Clinical and angiographic long-term follow-up of patients treated in this manner should be studied and reported.

Cerebrospinal fluid leak treated by aspiration and epidural blood patch under computed tomography guidance

BACKGROUND AND OBJECTIVES

Cerebrospinal fluid (CSF) leakage secondary to surgery of the spine is usually treated by drainage of CSF through a subarachnoid catheter or surgical repair of the dural tear. We present 2 cases in which the pseudomeningocele was treated by aspiration of the leaked CSF and blood patch under computed tomography (CT) guidance.

CASE REPORT

Two patients had headache after spine surgery. Physical examination showed a bulging accumulation of fluid at the laminectomy site. Aspiration of the fluid followed by injection of the patients' blood was performed aseptically under CT guidance. The patients had resolution of their headache, and follow-up showed no recurrence of the CSF leak.

CONCLUSIONS

CSF leak secondary to a surgical tear of the dura can be successfully treated by aspiration of the fluid followed by injection of the patient's blood. CT guidance is recommended to assess the extent of the CSF leakage, determine the degree of evacuation of the leaked CSF, and to confirm the injection of the blood into the epidural space and the space created by the pseudomeningocele.

The properties of retention intervals and their affect on retaining prospective memories

Five experiments were conducted to explore how the character of the retention interval affected event-based prospective memory. According to the canons of retrospective memory, prospective performance should have been worse with increasing delays between intention formation and the time it was appropriate to complete an action. That result did not occur. Rather, prospective memory was better with increasing retention intervals in Experiments 1A, 1B, and 3. In manipulating the nature of the retention interval, the authors found that there were independent contributions of retention interval length and the number of intervening activities, with more activities leading to better prospective memory (Experiments 2 and 3). The identical retention intervals did not improve retrospective memory in Experiment 4. Theoretical explanations for these dissociations between prospective and retrospective memory are considered.

Pituitary hypoplasia in patients with a mutation in the growth hormone-releasing hormone receptor gene

BACKGROUND AND PURPOSE

Several anatomic abnormalities of the pituitary gland have been described as occurring in association with congenital growth hormone deficiency, including hypoplasia of the adenohypophysis, truncation of the pituitary stalk, and ectopia of the neurohypophysis. Their pathogenesis, however, is obscure. Normal pituitary development is dependent on the sequential expression of a series of ontogenetic factors. Growth hormone-releasing hormone (GHRH) is known to stimulate somatotroph proliferation, and a dwarf mouse model with a mutant GHRH receptor, the "little mouse," has a small anterior pituitary due to hypoplasia of the somatotrophs. We recently described the human homolog of the little mouse (dwarfism of Sindh), caused by a homozygous nonsense mutation in the GHRH receptor gene in a Pakistani kindred. We investigated MR imaging characteristics to gain information regarding the potential role of GHRH in human pituitary organogenesis.

METHODS

MR images of the head were obtained of four affected male patients (age range, 22-29 years). Maximal anterior pituitary dimensions were determined from sagittal and coronal images, and pituitary volumes were estimated from cubic and ellipsoid formulae. The measurements were compared with normative values matched for age and sex.

RESULTS

The adenohypophysis was small in each of the four patients. The maximal height for the anterior pituitary was 3 mm in three patients and 2 mm in one (mean +/- SD, 2.75 +/- 0.5 mm), which is significantly (P < .001) less than the expected height of 5.6 +/- 1.0 mm for men in this age group. Estimates of anterior pituitary volume in the patients ranged from 75 to 124 mm3 (104 +/- 21 mm3), which corresponds to 35% to 52% of the normal mean volume corrected for small head size (P < .005). No other cranial abnormalities were identified.

CONCLUSION

We describe significant hypoplasia of the adenohypophysis occurring in four dwarfs with a nonsense mutation in the GHRH receptor. In addition to isolated growth hormone deficiency and severe dwarfism, affected patients have anterior pituitary hypoplasia, presumably due to somatotroph maldevelopment. Resistance to GHRH explains the hypoplasia of the adenohypophysis--a feature that contributes to growth hormone deficiency in this syndrome. This is one of the few instances in which the molecular basis of pituitary dysmorphogenesis has been identified.

Current approaches to imaging of the sellar region and pituitary

Recent advances in MR imaging have enabled the radiologist to view the pituitary gland in its normal and diseased states to a greater extent than ever before. The techniques for obtaining quality images of the sellar region and the normal appearance of the pituitary gland are discussed. This article also discusses the imaging of several pituitary disease processes, with emphasis on pitutiary adenomas and recent advances in diagnosis and follow-up. Current controversies also are addressed.

Persistence of the notochordal canal: MR and plain film appearance

We report a case of an unusually prominent persistent notochordal canal involving the T12-L5 vertebrae. This rare anatomic variation was discovered as an incidental finding in a patient with lymphoma undergoing MR imaging for evaluation of back pain. MR images showed a vertically oriented canal contiguous with the intervertebral disks traversing the anterior aspect of each affected vertebral body. Plain films showed a sclerotic rimmed central channel that flared at each vertebral endplate to merge with the disk spaces.

Imaging of angiographically occult cerebral vascular malformations

The angiographically occult vascular malformations represent an important cause of cerebral pathology. The propensity for significant yet often limited symptomatology provides for frequent challenge in clinical management. Understanding in diagnostic evaluation of occult vascular lesions is often limited by varying application of pathologic diagnosis and classification. This article attempts to clarify issues of classification while also discussing imaging evaluation and its role in clinical management.

T cell-depleted autologous hematopoietic stem cell transplantation for multiple sclerosis: report on the first three patients

Multiple sclerosis (MS) is a disease of the central nervous system characterized by immune-mediated destruction of myelin. In patients with progressive deterioration, we have intensified immunosuppression to the point of myeloablation. Subsequently, a new hematopoietic and immune system is generated by infusion of CD34-positive hematopoietic stem cells (HSC). Three patients with clinical MS and a decline of their Kurtzke extended disability status scale (EDSS) by 1.5 points over the 12 months preceding enrollment and a Kurtzke EDSS of 8.0 at the time of enrollment were treated with hematopoietic stem cell (HSC) transplantation using a myeloablative conditioning regimen of cyclophosphamide (120 mg/kg), methylprednisolone (4 g) and total body irradiation (1200 cGy). Reconstitution of hematopoiesis was achieved with CD34-enriched stem cells. The average time of follow-up is 8 months (range 6-10 months). Despite withdrawal of all immunosuppressive medications, functional improvements have occurred in all three patients. We conclude that T cell-depleted hematopoietic stem cell transplantation can be performed safely in patients with severe and debilitating multiple sclerosis. Stem cell transplantation has resulted in modest neurologic improvements for the first time since onset of progressive disease although no significant changes in EDSS or NRS scales are evident at this time.

Spontaneous intracranial hypotension: spinal MR findings

We report three patients with spontaneous intracranial hypotension in whom spinal MR imaging revealed ventral extradural fluid collections that were centered at the cervicothoracic junction in two patients and extended throughout the entire spine in the third patient. These spinal fluid collections most likely resulted from the accumulation of CSF at the site of dural leakage. Knowledge of this association can be helpful in the selection of imaging studies to facilitate diagnosis and treatment.

Contrast-enhanced magnetization transfer MR of the brain: importance of precontrast images

PURPOSE

To determine the importance of obtaining precontrast T1-weighted magnetization transfer (MT) MR images for better interpretation contrast-enhanced T1-weighted MT images.

METHODS

One hundred fifty-five patients referred for MR imaging of the brain were examined prospectively with noncontrast T1-weighted imaging, noncontrast T1-weighted imaging with MT, contrast-enhanced T1-weighted imaging, and contrast-enhanced T1-weighted imaging with MT. In the patients who had abnormally increased signal intensity on postcontrast images (with or without MT), the four imaging sequences were evaluated with regard to number of lesions and lesional signal intensity. For each of the sequences, two experienced neuroradiologists subjectively graded the lesions on a scale of 1 to 4 (4 being the most conspicuous) with regard to abnormally increased signal intensity.

RESULTS

Twenty-two of the 155 patients had increased signal intensity on one or more of the postcontrast sequences. Eight of these 22 patients had increased signal intensity of one or more lesions on images without MT. All these lesions were seen better on images obtained with MT. An additional six of the 22 patients had increased signal intensity of one or more lesions on images obtained with MT that was not detected on images obtained without MT. Eight of the 22 patients had no high signal intensity on noncontrast images with or without MT. One of the eight had increased number and conspicuity of lesions on postcontrast MT images.

CONCLUSIONS

A significant number of patients had increased signal intensity on noncontrast T1-weighted images with MT that was not seen on noncontrast T1-weighted images without MT. This high signal intensity was also visible on postcontrast MT images, and would have been mistaken for pathologic enhancement if noncontrast MT images had not been available for comparison.

Spinal cord venous infarction following endoscopic sclerotherapy for esophageal varices

The authors report an unusual case of venous infarction of the spinal cord associated with endoscopic sclerotherapy for esophageal varices. MR imaging findings included signal abnormalities and abnormal enhancement of the affected spinal cord and T-8 vertebral body. A review of the hemodynamic changes associated with portal hypertension and the normal venous drainage of the spinal cord is presented.