Sacral morel-lavallée lesion: a not-so-rare diagnosis.

Morel-Lavallée lesions are closed soft tissue degloving injuries with a propensity to become infected, arising in the lumbosacral region or even the scalp, common anatomical locations in neuroradiological studies. The radiologist must recognize this entity, its traumatic etiology, and treatment options. Our patient's Morel-Lavallée lesion was evaluated with ultrasound and MRI, demonstrating a predominantly hemorrhagic lesion successfully managed by aspiration.

Magnetic resonance imaging finding of empty sella in obesity related idiopathic intracranial hypertension is associated with enlarged sella turcica.

INTRODUCTION: Empty sella in MRI is an important finding associated with idiopathic intracranial hypertension (IIH). This study assesses the sensitivity and reproducibility of several morphological measures of the sella and pituitary gland to indentify the measure that best differentiates IIH from controls. Additionally, the study assesses reversal in gland compression following treatment. METHODS: Sagittal 3D-T1W sequence with 1 mm isotropic resolution was obtained from ten newly diagnosed IIH patients and 11 matched healthy controls. Follow-up MRI scans were obtained from eight patients at 1-week post-lumbar puncture and acetazolamide treatment. 1D and 2D measures of absolute and normalized heights and cross-sectional areas of the gland and sella were obtained to identify the measure that best differentiates IIH patients and controls. RESULTS: Overall area-based measurements had higher sensitivity than length with p < 0.0001 for sella area compared with p = 0.004 for normalized gland height. The gland cross-sectional areas were similar in both cohorts (p = 0.557), while the sella area was significantly larger in IIH, 200 ± 24 versus 124 ± 25 mm(2), with the highest sensitivity and specificity, 100% and 90.9%, respectively. Absolute gland area was the most sensitive measure for assessing post treatment changes, with 100% sensitivity and 50 % specificity. Average post-treatment gland area was 18% larger (p = 0.016). Yet, all eight patients remained within the empty sella range based on a normalized gland area threshold of 0.41. CONCLUSIONS: Sellar area is larger in IIH, and it demonstrated highest sensitivity for differentiating IIH from control subjects, while absolute gland area was more sensitive for detecting post treatment changes.

Discriminating radiation necrosis from tumor progression in gliomas: a systematic review what is the best imaging modality?

Differentiating post radiation necrosis from progression of glioma and pseudoprogression poses a diagnostic conundrum for many clinicians. As radiation therapy and temozolomide chemotherapy have become the mainstay of treatment for higher-grade gliomas, radiation necrosis and post treatment changes such as pseudoprogression have become a more relevant clinical problem for neurosurgeons and neurooncologists. Due to their radiological similarity to tumor progression, accurate recognition of these findings remains paramount given their vastly different treatment regimens and prognoses. However, no consensus has been reached on the optimal technique to discriminate between these two lesions. In order to clarify the types of imaging modalities for recurrent enhancing lesions, we conducted a systematic review of case reports, case series, and prospective studies to increase our current understanding of the imaging options for these common lesions and their efficacy. In particular, we were interested in distinguishing radiation necrosis from true tumor progression. A PubMed search was performed to include all relevant studies where the imaging was used to differentiate between radiation necrosis and recurrent gliomas with post-radiation enhancing lesions. After screening for certain parameters in our study, seventeen articles with 435 patients were included in our analysis including 10 retrospective and 7 prospective studies. The average time from the end of radiation therapy to the onset of a recurrent enhancing lesion was 13.2 months. The most sensitive and specific imaging modality was SPECT with a sensitivity of 87.6 % and specificity of 97.8 %. Based on our review, we conclude that certain imaging modalities may be preferred over other less sensitive/specific techniques. Overall, tests such as SPECT may be preferable in differentiating TP (tumor progression) from RN (radiation necrosis) due to its high specificity, while nonspecific imaging such as conventional MRI is not ideal.

Evidence for altered spinal canal compliance and cerebral venous drainage in untreated idiopathic intracranial hypertension.

Idiopathic intracranial hypertension (IIH), or pseudotumor cerebri, is a debilitating neurological disorder characterized by elevated CSF pressure of unknown cause. IIH manifests as severe headaches, and visual impairments. Most typically, IIH prevails in overweight females of childbearing age and its incidence is rising in parallel with the obesity epidemic. The most accepted theory for the cause of IIH is reduced absorption of CSF due to elevated intracranial venous pressure. A comprehensive MRI study, which includes structural and physiological imaging, was applied to characterize morphological and physiological differences between a homogeneous cohort of female IIH patients and an age- and BMI-similar control group to further elucidate the underlying pathophysiology. A novel analysis of MRI measurements of blood and CSF flow to and from the cranial and spinal canal compartments employing lumped parameters modeling of the cranio-spinal biomechanics provided, for the first time, evidence for the involvement of the spinal canal compartment. The CSF space in the spinal canal is less confined by bony structures compared with the cranial CSF, thereby providing most of the craniospinal compliance. This study demonstrates that the contribution of spinal canal compliance in IIH is significantly reduced.

Determination of cranio-spinal canal compliance distribution by MRI: Methodology and early application in idiopathic intracranial hypertension.

PURPOSE: To develop a method for derivation of the cranial-spinal compliance distribution, assess its reliability, and apply to obese female patients with a diagnosis of idiopathic intracranial hypertension (IIH). MATERIALS AND METHODS: Phase contrast-based measurements of blood and cerebrospinal fluid (CSF) flows to, from, and between the cranial and spinal canal compartments were used with lumped-parameter modeling to estimate systolic volume and pressure changes from which cranial and spinal compliance indices are obtained. The proposed MRI indices are analogous to pressure volume indices (PVI) currently being measured invasively with infusion-based techniques. The consistency of the proposed method was assessed using MRI data from seven aged healthy subjects. Measurement reproducibility was assessed using five repeated MR scans from one subject. The method was then applied to compare spinal canal compliance contribution in seven IIH patients and six matched healthy controls. RESULTS: In the healthy subjects, as expected, spinal canal contribution was consistently larger than the cranial contribution (average value of 69%). Measurement variability was 8%. In IIH, the spinal canal contribution is significantly smaller than normal controls (60 versus 78%, P < 0.03). CONCLUSION: An MRI-based method for derivation of compliance indices analogous to PVI has been implemented and applied to healthy subjects. The application of the method to obese IIH patients suggests a spinal canal involvement in the pathophysiology of IIH.

Osteoblastoma of the frontal sinuses presenting with headache and blurred vision: case report and review of the literature.

Osteoblastoma is a rare benign bone tumor that usually arises in the vertebral column and long bones of young adults. Craniofacial involvement is extremely rare. To date, osteoblastoma of the frontal sinus has not been reported in the English literature. We report an osteoblastoma of both frontal sinuses in a 23-year-old male who presented with headache and blurry vision in the left eye. Computed tomography (CT) demonstrated an expansile lesion involving both frontal sinuses with sclerotic and fibrous components, eroding into the roof of the left orbit. On magnetic resonance imaging (MRI) the dense portion of the lesion showed signal void on all sequences, while the fibrous matrix was isointense to grey matter on T1-weighted and T2-weighted images and showed avid enhancement following intravenous contrast administration. Surgical resection was performed and histology was consistent with osteoblastoma.

Magnetic resonance imaging findings after uneventful continuous infusion neuraxial analgesia: a prospective study to determine whether epidural infusion produces pathologic magnetic resonance imaging findings.

BACKGROUND: Magnetic resonance imaging (MRI) is considered the preferred diagnostic tool to determine whether postepidural neurologic symptoms are due to hematoma or abscess. However, there is currently no published information regarding the normal appearance of a MRI after a continuous epidural infusion. In this prospective cohort study, we defined the characteristic appearance of MRI findings after uneventful epidural analgesia. METHODS: Thirty women were prospectively enrolled to undergo a lumbar MRI after labor and delivery. The study group consisted of 15 women who received neuraxial analgesia with a combined spinal epidural technique followed by continuous epidural infusion, whereas the control group included 15 women who delivered without receiving neuraxial analgesia. All patients received a MRI within 12 h of delivery via a 1.5T scanner. MRIs were reviewed by two neuroradiologists who were blinded to the patient's study group allocation and asked to document the presence or absence of fluid collection, air collection, or soft tissue abnormalities. RESULTS: There were no radiologically significant fluid collections, hematomas, or mass effects noted on the thecal sac of any of the 30 MRI studies. A small amount of epidural air was seen in 77% of MRI studies after epidural analgesia, but there was no indention on the thecal sac. CONCLUSIONS: The lack of significant collections or mass effects seen in the MRIs of our patients after continuous infusion of epidural analgesia suggests that the presence of these findings in a patient with new neurologic symptoms after administration of epidural analgesia should be considered pathologic and warrant immediate attention.

Normal and abnormal imaging findings in lumbar total disk replacement: devices and complications.

Fusion, with or without laminectomy, is the standard treatment for symptomatic lumbar degenerative disk disease when conservative management has failed. Yet even radiographically verified solid fusion may be accompanied by considerable long-term problems, including recurrent low back pain, spinal stenosis, hypertrophic facet disease, pseudarthrosis, and spondylolysis and spondylolisthesis at adjacent levels. Several studies have shown a relationship between solid fusion and the development of adjacent-level disk disease, which is thought to result from increased stress on, or hypermobility of, adjacent segments. Total disk replacement (TDR) was developed as a way to restore normal mobility of the diseased segments and improve clinical outcomes by decreasing the risk of adjacent-level degenerative disease and related complications. However, like fusion, TDR is associated with various complications; some of these (eg, migration, subsidence) may occur regardless of the device used, whereas others (eg, extrusion of the polyethylene inlay, vertical fractures) are device specific. Facet arthrosis, device wear, particle disease, adjacent-level degeneration, and heterotopic ossification also have been observed after TDR, but the frequency and importance of these findings remain uncertain. Given the increasing use of lumbar TDR to treat degenerative disk disease, it is important that radiologists be familiar with the most commonly used devices and the potential complications of their use.

Evaluation of magnetic resonance imaging following neuraxial steroid administration: does epidural injection produce pathologic findings?

BACKGROUND AND OBJECTIVES: Infection or hematoma following epidural anesthesia is a rare but potentially devastating complication unless diagnosed early. In order to diagnose spinal cord involvement, the currently recommended imaging test is magnetic resonance imaging (MRI). Despite this, no previous studies have been performed to define typical MRI findings following uneventful epidural injection. The purpose of this pilot study was to compare magnetic resonance images before and after epidural injection to define the characteristic appearance of MRI following an uneventful epidural steroid injection. METHODS: Ten patients were prospectively enrolled and received an MRI study before and after an epidural injection of steroids plus local anesthetic for chronic low back pain using a loss of resistance to air technique. The magnetic resonance images were reviewed by 2 neuroradiologists who were blinded as to whether the scan was performed before or after the epidural injection. RESULTS: Review of 20 MRI studies revealed no fluid collections, hematomas, or mass effect on the thecal sac. A needle track and a small amount of epidural air was seen in the majority of post-epidural scans, but did not cause indentation of the thecal sac in any patient. None of the findings observed by the radiologists in the post-epidural scans were considered clinically significant. CONCLUSIONS: The results of this pilot study demonstrated that after uneventful epidural injection in otherwise healthy patients, there were no new pathologic findings on MRI scans. Further MRI studies in large populations and in different clinical situations should be performed to confirm these preliminary findings.

Sinonasal intestinal-type adenocarcinoma involvement of the paranasal sinuses.

We present a patient with a biopsy-proved sinonasal intestinal-type adenocarcinoma who presented with moderate confusion. He was found to have bifrontal hemorrhages, which to our knowledge has not been previously described in the literature for this entity. Intestinal-type adenocarcinoma should be in the differential diagnosis of aggressive lesions in the base of the skull with intracranial spread from the paranasal sinuses.

Proton MR spectroscopy of gliomatosis cerebri: case report of elevated myoinositol with normal choline levels.

A 69-year-old woman presented with clinical and imaging findings suspicious for gliomatosis cerebri, later confirmed by biopsy (moderately cellular, infiltrating glioma). Single voxel proton MR spectroscopy (TE 20 and TE 135) and spectroscopic imaging (TE 135) performed at admission showed normal choline, decreased N-acetyl, and elevated myo-inositol levels relative to creatine. The primary conclusion is that in suspected cases of gliomatosis cerebri, myo-inositol/creatine and myo-inositol/N-acetyl should be determined because they may provide evidence of tumor, even though choline/creatine is normal. A corollary to this conclusion is that choline/creatine may be misleading if used to demarcate infiltrating glioma from edema.

Detection of spinal dural arteriovenous fistulae with MR imaging and contrast-enhanced MR angiography: sensitivity, specificity, and prediction of vertebral level.

BACKGROUND AND PURPOSE: MR imaging and contrast-enhanced MR angiography have been used to detect evidence of spinal dural arteriovenous fistulae (AVF); however, the sensitivity and specificity of these techniques have not been shown. The purpose of this study was to establish the sensitivity, specificity, and accuracy of MR imaging alone compared with MR imaging plus MR angiography in determining whether dural AVF are present and to establish the accuracy of MR angiography in predicting fistula level. METHODS: Twenty patients with surgically proven dural AVF (diagnosed with radiographic digital subtraction angiography) and 11 control patients who had normal digital subtraction angiography findings underwent routine MR imaging plus 3D contrast-enhanced MR angiography of the spine. Images were reviewed in two stages (stage I, MR images only; stage II, MR images plus MR angiograms) by three neuroradiologists who were blinded to the final diagnoses. RESULTS: The sensitivity, specificity, and accuracy of the three reviewers in detecting the presence of fistulae ranged from 85% to 90%, from 82% to 100%, and from 87% to 90%, respectively, for stage I, compared with values of 80% to 100%, 82%, and 81% to 94%, respectively, for stage II. For each reviewer, there was no significant difference between the values for stages I and II; however, among the reviewers, one of the more experienced neuroradiologists had significantly greater sensitivity than a less experienced neuroradiologist for stage II. On average, the percentage of true positive results for which the correct fistula level was predicted increased from 15% for stage I to 50% for stage II, and the correct level +/- one level was predicted in 73% for stage II. MR evidence of increased intradural vascularity was significantly greater in patients with dural AVF. CONCLUSION: The addition of MR angiography to standard MR imaging of the spine may improve sensitivity in the detection of spinal dural fistulae. The principal benefit of MR angiography is in the improved localization of the vertebral level of the fistula, which potentially expedites the subsequent digital subtraction angiography study.