Cranial Nerve Palsies in the Setting of Arachnoid Cysts: A Case Series and Literature Review

BACKGROUND

Arachnoid cysts (ACs) are benign lesions typically believed to not cause neurologic defects in the adult population and are most often found incidentally on imaging. We describe 2 patients with ACs potentially leading to isolated cranial nerve (CN) dysfunction.

METHODS

We describe 2 patients, 1 with a fourth nerve palsy and the other with a sixth nerve palsy found to have ACs on MRI brain imaging in locations that potentially caused a compressive CN palsy. We review previous literature of ACs presenting with CN III, IV, or VI palsy.

RESULTS

Patient 1 was a 62-year-old man who presented with a 22-year history of diplopia with strabismus examination consistent with a congenital CN IV palsy. Despite multiple surgeries, his CN IV palsy insidiously worsened. An AC in the posterior fossa with mass effect on the quadrigeminal plate and asymmetric atrophy of the right superior oblique was identified on imaging. Patient 2 was an 80-year-old man who presented with an 18-year history of diplopia and was found to have a left esotropia and abduction deficit consistent with complete CN VI palsy. An AC in the left cavernous sinus was identified on imaging. He underwent strabismus surgery with satisfactory resolution of diplopia. We identified a total of 18 previously published cases: 8 reports of CN III palsy, 4 reports of CN IV palsy, and 6 reports of CN VI palsy. Patient ages ranged from 1 to 67 with a median of 34.5. In 16/18 (89%) cases, the diagnosis of ACs was made within 1 year of symptom onset. Surgical removal of the AC was successful in resolving diplopia in 7/12 (58%) cases. In no case was strabismus surgery performed as primary treatment.

CONCLUSIONS

Although ACs are typically congenital asymptomatic lesions, we present a case series of 2 patients with ACs in anatomic locations that potentially caused chronic, progressive, isolated CN palsies leading to strabismus. Our literature review revealed that most published cases detailing this clinical scenario resulted in neurosurgical fenestration of ACs with mixed results. Our cases represent 2 patients with AC-associated CN palsy treated with strabismus surgery.

Predictors of salvage therapy for parasagittal meningiomas treated with primary surgery, radiosurgery, or surgery plus adjuvant radiotherapy

OBJECTIVE

Parasagittal meningiomas (PM) are treated with primary microsurgery, radiosurgery (SRS), or surgery with adjuvant radiation. We investigated predictors of tumor progression requiring salvage surgery or radiation treatment. We sought to determine whether primary treatment modality, or radiologic, histologic, and clinical variables were associated with tumor progression requiring salvage treatment.

METHODS

Retrospective study of 109 consecutive patients with PMs treated with primary surgery, radiation (RT), or surgery plus adjuvant RT (2000-2017) and minimum 5 years follow-up. Patient, radiologic, histologic, and treatment data were analyzed using standard statistical methods.

RESULTS

Median follow up was 8.5 years. Primary treatment for PM was surgery in 76 patients, radiation in 16 patients, and surgery plus adjuvant radiation in 17 patients. Forty percent of parasagittal meningiomas in our cohort required some form of salvage treatment. On univariate analysis, brain invasion (OR: 6.93, p < 0.01), WHO grade 2/3 (OR: 4.54, p < 0.01), peritumoral edema (OR: 2.81, p = 0.01), sagittal sinus invasion (OR: 6.36, p < 0.01), sagittal sinus occlusion (OR: 4.86, p < 0.01), and non-spherical shape (OR: 3.89, p < 0.01) were significantly associated with receiving salvage treatment. On multivariate analysis, superior sagittal sinus invasion (OR: 8.22, p = 0.01) and WHO grade 2&3 (OR: 7.58, p < 0.01) were independently associated with receiving salvage treatment. There was no difference in time to salvage therapy (p = 0.11) or time to progression (p = 0.43) between patients receiving primary surgery alone, RT alone, or surgery plus adjuvant RT. Patients who had initial surgery were more likely to have peritumoral edema on preoperative imaging (p = 0.01). Median tumor volume was 19.0 cm3 in patients receiving primary surgery, 5.3 cm3 for RT, and 24.4 cm3 for surgery plus adjuvant RT (p < 0.01).

CONCLUSION

Superior sagittal sinus invasion and WHO grade 2/3 are independently associated with PM progression requiring salvage therapy regardless of extent of resection or primary treatment modality. Parasagittal meningiomas have a high rate of recurrence with 80.0% of patients with WHO grade 2/3 tumors with sinus invasion requiring salvage treatment whereas only 13.6% of the WHO grade 1 tumors without sinus invasion required salvage treatment. This information is useful when counseling patients about disease management and setting expectations.

Monkeypox-Associated Central Nervous System Disease: A Case Series and Review

OBJECTIVE

Monkeypox virus (MPXV) disease has been declared a public health emergency by the World Health Organization, creating an urgent need for neurologists to be able to recognize, diagnosis, and treat MPXV-associated neurologic disease.

METHODS

Three cases of MPXV-associated central nervous system (CNS) disease occurring during the 2022 outbreak, and their associated imaging findings are presented, with 2 cases previously published in a limited capacity in a public health bulletin.

RESULTS

Three previously healthy immunocompetent gay men in their 30s developed a febrile illness followed by progressive neurologic symptoms with presence of a vesiculopustular rash. MPXV nucleic acid was detected by polymerase chain reaction (PCR) from skin lesions of 2 patients, with the third patient having indeterminate testing but an epidemiologic link to a confirmed MPXV disease case. Cerebrospinal fluid demonstrated a lymphocytic pleocytosis, elevated protein, and negative MPXV-specific PCR. In 2 patients, magnetic resonance imaging of the brain and spine demonstrated partially enhancing, longitudinally extensive central spinal cord lesions with multifocal subcortical, basal ganglia, thalamic, cerebellar, and/or brainstem lesions. The third patient had thalamic and basal ganglia lesions. All patients received 14 days of tecovirimat, and 2 patients also received multiple forms of immunotherapy, including intravenous immunoglobulin, pulsed high-dose steroids, plasmapheresis, and/or rituximab. Good neurologic recovery was observed in all cases.

INTERPRETATION

MPXV can be associated with CNS disease. It is unclear whether this is from a parainfectious immune-mediated injury or direct CNS viral invasion. ANN NEUROL 2023.

Case Report: Anterior Spinal Cord Ischemia Following Embolization of Cerebellar Arteriovenous Malformation: An Illustrative Case and Review of Spinal Cord Vascular Anatomy

Spinal cord ischemia (SCI) is a rare entity with high mortality and morbidity which can arise from causes such as atherosclerosis, aortic dissection or aneurysm, thromboembolic events or systemic hypotension, and is a potential complication of spinal surgery. Published literature contains very few reports of SCI as a complication of intracranial interventions, highlighting the uncommon nature of SCI in these circumstances. We report the occurrence of anterior SCI in a 69-year-old patient following successful embolization of a cerebellar arteriovenous malformation (AVM), marked by upper extremity weakness, lower extremity paraplegia, loss of bladder and bowel control, and hypercapnic respiratory failure requiring mechanical ventilation. Magnetic resonance imaging (MRI) demonstrated upper cervical diffusion restriction and T2/STIR hyperintensity. Unusually, SCI occurred in this case without intraprocedural catheter wedging or obvious flow limitation, prolonged procedure time, hypercoagulable state, or general hypotension. We review previous cases in the literature as well as spinal cord vascular anatomy, and discuss the possible etiologies of this complication. Spinal cord ischemia could be a very rare complication of neuroendovascular procedures even in the absence of warning signs and should be carefully evaluated in patients with suspected neurologic symptoms after such procedures.

Autosomal Dominant Polycystic Kidney Disease and Intracranial Aneurysms: Is There an Increased Risk of Treatment?

BACKGROUND AND PURPOSE

Autosomal dominant polycystic kidney disease is associated with an increased risk of intracranial aneurysms. Our purpose was to assess whether there is an increased risk during aneurysm coiling and clipping.

MATERIALS AND METHODS

Data were obtained from the National Inpatient Sample (2000-2011). All subjects had an unruptured aneurysm clipped or coiled and were divided into polycystic kidney (n = 189) and control (n = 3555) groups. Primary end points included in-hospital mortality, length of stay, and total hospital charges. Secondary end points included the International Classification of Diseases, Ninth Revision codes for iatrogenic hemorrhage or infarction; intracranial hemorrhage; embolic infarction; and carotid and vertebral artery dissections.

RESULTS

There was a significantly greater incidence of iatrogenic hemorrhage or infarction, embolic infarction, and carotid artery dissection in the patients with polycystic kidney disease compared with the control group after endovascular coiling. There was also a significantly greater incidence of iatrogenic hemorrhage or infarction in the polycystic kidney group after surgical clipping. However, the hospital stay was not longer in the polycystic kidney group, and the total hospital charges were not higher. Additional analysis within the polycystic kidney group revealed a significantly shorter length of stay but similar in-hospital costs when subjects underwent coiling versus clipping.

CONCLUSIONS

Patients with polycystic kidney disease face an increased risk during intracranial aneurysm treatment, whether by coiling or clipping. This risk, however, does not translate into longer hospital stays or increased hospital costs. Despite the additional catheterization-related risks of dissection and embolization, coiling results in shorter hospital stays and similar mortality compared with clipping.

Endovascular correction of an infantile intracranial venous outflow obstruction

The authors report on the case of a 7-year-old boy who presented with a reduced level of activity, macrocephaly, prominent scalp veins, and decreased left-sided visual acuity. Imaging workup demonstrated generalized cerebral volume loss, bilateral chronic subdural hematomas, absent left sigmoid sinus, hypoplastic left transverse sinus, and severe focal weblike stenosis of the right sigmoid sinus. Right sigmoid sinus angioplasty and stent insertion was performed, with an immediate reduction in the transduced intracranial venous pressure gradient across the stenosis (from 22 to 3 mm Hg). Postprocedural diminution of prominent scalp and forehead veins and spinal venous collateral vessels was followed by a progressive improvement in visual acuity and physical activity over a 1-year follow-up period, supporting the efficacy of angioplasty and stent insertion in intracranial venous outflow obstruction. There are multiple potential causes of intracranial venous hypertension in children. Development of dural sinus stenosis in infancy may be one such cause, mimicking the clinical presentation of other causes such as vein of Galen malformations. This condition can be ameliorated by early endovascular revascularization.

Should patients with autosomal dominant polycystic kidney disease be screened for cerebral aneurysms?

Autosomal dominant polycystic kidney disease is a genetic disorder affecting 1 in 1000 people worldwide and is associated with an increased risk of intracranial aneurysms. It remains unclear whether there is sufficient net benefit to screening this patient population for IA, considering recent developments in imaging and treatment and our evolving understanding of the natural history of unruptured aneurysms. There is currently no standardized screening protocol for IA in patients with ADPCKD. Our review of the literature focused on the above issues and presents our appraisal of the estimated value of screening for IA in the setting of ADPCKD.

Will CT ordering practices change if we educate residents about the potential effects of radiation exposure? Experience at a large academic medical center

RATIONALE AND OBJECTIVES

The aim of this study was to determine if educating residents about the potential effects of radiation exposure from computed tomographic (CT) imaging alters ordering patterns. This study also explored whether referring physicians are interested in radiation education and was an initial effort to address their CT ordering behavior.

MATERIALS AND METHODS

Two to four months after a radiologist's lecture on the potential effects of radiation exposure related to CT scans, urology and orthopedic residents were surveyed regarding the number and types of CT scans they ordered, the use of alternative imaging modalities, and whether they used the lecture information to educate patients.

RESULTS

Twenty-one resident lecture attendants completed the survey. The number of CT scans ordered after the lecture stayed constant for 90% (19 of 21) and decreased for 10% (two of 21). The types of CT scans ordered changed after the lecture for 14% (three of 21). Thirty-three percent (seven of 21) reported increases in alternative imaging after the lecture, including 24% (five of 21) reporting increases in magnetic resonance imaging and 19% (four of 21) reporting increases in ultrasound. Patients directed questions about radiation exposure to 57% (12 of 21); 38% (eight of 21) used the lecture information to educate patients. Referring physicians were interested in the topic, and afterward, other physician groups requested radiation education lectures.

CONCLUSIONS

Most clinicians did not change their CT scan ordering after receiving education about radiation from a radiologist. Radiation education allowed clinicians to discuss CT benefits and risks with their patients and to choose appropriate CT protocols. Referring physician groups are interested in this topic, and radiologists should be encouraged to give radiation lectures to them.

Cervical epidural arteriovenous fistula presenting with radiculopathy: transvenous embolization using Onyx

We present an uncommon case of cervical epidural arteriovenous fistula presenting with radiculopathy that was successfully treated with transvenous embolization using Onyx.

Blood pressure reduction, decreased diffusion on MRI, and outcomes after intracerebral hemorrhage

BACKGROUND AND PURPOSE

Decreased diffusion (DD) consistent with acute ischemia may be detected on MRI after acute intracerebral hemorrhage (ICH), but its risk factors and impact on functional outcomes are not well-defined. We tested the hypotheses that DD after ICH is related to acute blood pressure (BP) reduction and lower hemoglobin and presages worse functional outcomes.

METHODS

Patients who underwent MRI were prospectively evaluated for DD by certified neuroradiologists blinded to outcomes. Hemoglobin and BP data were obtained via electronic queries. Outcomes were obtained at 14 days and 3 months with the modified Rankin Scale, a functional scale scored from 0 (no symptoms) to 6 (dead). We used logistic regression for dependence or death (modified Rankin Scale score 4-6).

RESULTS

DD distinct from the hematoma was found on MRI in 39 of 95 patients (41%). DD was associated with greater BP reductions from baseline and a higher risk of dependence or death at 3 months (odds ratio, 4.8; 95% confidence interval, 1.7-13.9; P=0.004) after correction for ICH score (1.8 per point; 95% confidence interval, 1.2-3.1; P=0.01). Lower hemoglobin was associated with worse ICH score, larger hematoma volume, and worse outcomes, but not DD.

CONCLUSIONS

DD is common after ICH, associated with greater acute BP reductions, and associated with disability and death at 3 months in multivariate analysis. The potential benefits of acute BP reduction to reduce hematoma growth may be limited by DD. The prevention and treatment of cerebral ischemia manifested as DD are potential methods to improve outcomes.

Solitary intramedullary plasmacytoma of the skull base mimicking aggressive meningioma

The authors present an unusual case of solitary intramedullary plasmacytoma. Awareness of this entity can facilitate appropriate surgical planning, which may include a limited biopsy prior to considering more extensive skull base surgery.

Reversal of Diffusion Restriction After Embolization of Dural Arteriovenous Fistula: Case Report

BACKGROUND AND IMPORTANCE:

We report a rare case of diffusion restriction caused by venous hypertension resulting from a dural arteriovenous fistula (DAVF) that completely reversed after successful embolization.

CLINICAL PRESENTATION:

A 54-year-old man presented with symptoms secondary to a DAVF. Magnetic resonance imaging (MRI) revealed left parieto-temporo-occipital diffusion restriction. The angiogram revealed a Cognard type III left lateral tentorial DAVF resulting in severe venous hypertension. Transarterial Onyx embolization was performed, resulting in angiographic cure of the fistula with normalization of the venous drainage in the left parieto-temporo-occipital region. A follow-up MRI examination performed 4 weeks after the embolization revealed resolution of the previously seen area of restricted diffusion.

CONCLUSION:

It is important to consider the possibility of diffusion restriction reversal, because misdiagnosis or the false assumption that irreversible cerebral infarction has occurred may inappropriately alter or delay the treatment of these aggressive lesions.

The use of the "puffed-cheek" computed tomography technique to confirm the diagnosis of pneumoparotitis

Pneumoparotitis is a rare etiology of symptomatic parotid gland enlargement that is often misdiagnosed clinically. Pneumoparotitis results from air refluxing into the parotid ductal system via an incompetent Stensen duct orifice. We report a protracted case of pneumoparotitis evaluated with the "puffed-cheek" computed tomography technique to help confirm the diagnosis.

PERSISTENT TRIGEMINAL ARTERY TERMINATING IN THE POSTERIOR INFERIOR CEREBELLAR ARTERY

OBJECTIVE

Persistent trigeminal arteries are rare and represent a remnant of the fetal carotid-basilar circulation. They typically extend from the internal carotid artery to the basilar artery. An unusual case of a patient with a trigeminal artery originating from the internal carotid artery and terminating as the dominant hemispheric branch of the posterior inferior cerebellar artery is presented.

CLINICAL PRESENTATION

A 66-year-old woman presented to the emergency department with pulsatile tinnitus, increasing left eye pain, proptosis, conjunctival injection, diplopia, and decreased visual acuity. Conventional contrast-enhanced computed tomographic and magnetic resonance imaging demonstrated findings consistent with a left carotid-cavernous fistula. The patient underwent an emergency diagnostic cerebral angiogram. Besides an indirect carotid-cavernous fistula on the left side, a right-sided persistent trigeminal artery terminating as the dominant hemispheric trunk of the posteroinferior cerebellar artery was incidentally noted. The vermian branch of the right posteroinferior cerebellar artery arose from the ipsilateral vertebral artery, whereas duplicate superior cerebellar arteries supplied the left posteroinferior cerebellar artery region.

INTERVENTION

The patient was treated for the indirect carotid-cavernous fistula with detachable platinum coils and N-butyl cyanoacrylate, resulting in the resolution of her symptoms.

CONCLUSION

We report a case of a persistent trigeminal artery supplying only the cerebellar hemisphere. The clinical significance of this anomaly relates to its role in endovascular therapeutic and surgical complications and the paradoxical lesions in the cerebellum that occur as a result of carotid disease. We also discuss the Saltzman classification of persistent trigeminal arteries and their variants.

Linkage to chromosome 2q36.1 in autosomal dominant Dandy-Walker malformation with occipital cephalocele and evidence for genetic heterogeneity

We previously reported a Vietnamese-American family with isolated autosomal dominant occipital cephalocele. Upon further neuroimaging studies, we have recharacterized this condition as autosomal dominant Dandy-Walker with occipital cephalocele (ADDWOC). A similar ADDWOC family from Brazil was also recently described. To determine the genetic etiology of ADDWOC, we performed genome-wide linkage analysis on members of the Vietnamese-American and Brazilian pedigrees. Linkage analysis of the Vietnamese-American family identified the ADDWOC causative locus on chromosome 2q36.1 with a multipoint parametric LOD score of 3.3, while haplotype analysis refined the locus to 1.1 Mb. Sequencing of the five known genes in this locus did not identify any protein-altering mutations. However, a terminal deletion of chromosome 2 in a patient with an isolated case of Dandy-Walker malformation also encompassed the 2q36.1 chromosomal region. The Brazilian pedigree did not show linkage to this 2q36.1 region. Taken together, these results demonstrate a locus for ADDWOC on 2q36.1 and also suggest locus heterogeneity for ADDWOC.

Coil embolization of posttraumatic pseudoaneurysm of the ophthalmic artery causing subarachnoid hemorrhage

✓The authors report a unique case of subarachnoid hemorrhage caused by a traumatic pseudoaneurysm of the ophthalmic artery, which was successfully treated with coil embolization. Clinical and imaging features, as well as the relevant literature, are described.

Pulsatility Imaging of Saccular Aneurysm Model by 64-Slice CT with Dynamic Multiscan Technique

The feasibility of imaging pulsatility in an aneurysm model with the high-resolution dynamic multiscan technique of 64-slice computed tomography (CT) was studied. A pulsatile aneurysm phantom was constructed and imaged with dynamic multiscan technique. The aneurysm model was filled with iodinated contrast material (250 Hounsfield Units) and was scanned with use of a gantry rotation time of 0.33 seconds, slice thickness of 1.2 mm, effective coverage of 24 mm, and total imaging time of 4 seconds. Images were reconstructed at 50-msec intervals. The visualization of wall motion was qualitatively evaluated by direct comparison of four-dimensional images versus phantom motion. Pulsatility imaging without perceptible artifact or need for cardiac gating was achieved with the use of this technique.

Primary treatment of an indirect carotid cavernous fistula by injection of N-butyl cyanoacrylate in the dural wall of the cavernous sinus

BACKGROUND

Carotid cavernous fistulae are abnormal communications between the carotid artery system and the cavernous sinus. Endovascular treatment is the treatment of choice, but because of their heterogeneous etiology and anatomy, an appropriate treatment plan must be tailored for each patient.

CASE DESCRIPTION

A 77-year-old diabetic woman presented with rapid onset of right eye pain, conjunctivitis, and chemosis. Angiography revealed an indirect CCF located in the posterior wall of the right cavernous sinus. N-Butyl cyanoacrylate was injected directly into the fistula site in the dural wall via a microcatheter, resulting in a cure.

CONCLUSION

We describe an unconventional treatment of an indirect CCF from an IPS approach. One type D(2) CCF was treated successfully using only N-butyl cyanoacrylate injected directly at the fistula site. This was achieved by microcatheterization of the fistula in the posterior wall of the right cavernous sinus.

Spinal arteriovenous malformations associated with Klippel-Trenaunay-Weber syndrome: a literature search and report of two cases

SUMMARY

Patients with Klippel-Trenaunay-Weber syndrome present with venous varices, cutaneous capillary malformations, and tissue hypertrophy, usually involving an extremity. A small but important subset also harbors arteriovenous malformations (AVMs) of the spine. We report 2 such cases, 1 with 3 concurrent spinal arteriovenous fistulas. These cases and our review of the literature emphasize the importance of screening the spine for AVMs. In addition, it is also important to investigate for the presence of multiple spinal AVMs.

Extradural spinal meningioma as a source of plasmacytoid cells. A case report

BACKGROUND

Meningiomas, tumors that often affect middle-aged and elderly people, occasionally arise in the spine, typically at the thoracic level. The cytologic findings in meningiomas include whorls and syncytial clusters of bland-looking cells with scattered, psammomatous calcifications and intranudclear cytoplasmic inclusions. However, in many cases, not all these findings are seen, and in rare cases, unusual cytomorphologic features are observed.

CASE

A case of spinal meningioma was located in the extradural compartment and composed predominantly of singly scattered cells with a plasmacytoid appearance, demonstrated on fine needle aspiration biopsy smear preparations. The cell block showed more typical features of meningioma, and the diagnosis was supported by the results of immunohistochemical staining.

CONCLUSION

The diagnosis of spinal meningioma is readily made by employing magnetic resonance imaging. The diagnosis can be difficult to confirm pathologically when atypical histologic findings are present, as in this case, with prominent plasmacytoid features. Sections from the cell block and immunohistochemical stains as well as clinical and radiologic findings were extremely helpful in arriving at the final diagnosis.

MR angiographic evaluation of platinum coil packs at 1.5T and 3T: an in vitro assessment of artifact production: technical note

Susceptibility artifact from platinum coil packs impairs the visibility of perianeurysmal soft tissues at conventional 3D time-of-flight MR angiography. These artifacts limit the evaluation for residual-recurrent aneurysm and parent vessel stenosis. Reducing the echo time can decrease the artifact and improve perianeurysmal visualization. The purpose of this study was to assess quantitatively the effect of decreasing the echo time on artifact production at different field strengths and coil pack densities.

Rheolytic catheter thrombectomy, balloon angioplasty, and direct recombinant tissue plasminogen activator thrombolysis of dural sinus thrombosis with preexisting hemorrhagic infarctions

We describe the case of a 28-year-old obtunded woman who presented with bilateral anterior parietal lobe cortical hemorrhages associated with thrombosis of the superior sagittal sinus, both transverse and sigmoid sinuses, and multiple cortical veins draining into the sagittal sinus. Initial heparin therapy was not effective. A combination of AngioJet rheolytic catheter thrombectomy, balloon angioplasty, and continuous direct superior sagittal sinus recombinant tissue plasminogen activator infusion led to venous recanalization with a successful clinical outcome, without worsening of the preexisting intracranial hemorrhages.

Radiation Doses in Interventional Radiology Procedures: The RAD-IR Study

PURPOSE

To present the physics data supporting the validity of the clinical dose data from the RAD-IR study and to document the performance of dosimetry-components of these systems over time.

MATERIALS AND METHODS

Sites at seven academic medical centers in the United States prospectively contributed data for each of 12 fluoroscopic units. All units were compatible with International Electrotechnical Commission (IEC) standard 60601-2-43. Comprehensive evaluations and periodic consistency checks were performed to verify the performance of each unit's dosimeter. Comprehensive evaluations compared system performance against calibrated ionization chambers under nine combinations of operating conditions. Consistency checks provided more frequent dosimetry data, with use of each unit's built-in dosimetry equipment and a standard water phantom.

RESULTS

During the 3-year study, data were collected for 48 comprehensive evaluations and 581 consistency checks. For the comprehensive evaluations, the mean (95% confidence interval range) ratio of system to external measurements was 1.03 (1.00-1.05) for fluoroscopy and 0.93 (0.90-0.96) for acquisition. The expected ratio was 0.93 for both. For consistency checks, the values were 1.00 (0.98-1.02) for fluoroscopy and 1.00 (0.98-1.02) for acquisition. Each system was compared across time to its own mean value. Overall uncertainty was estimated by adding the standard deviations of the comprehensive and consistency measurements in quadrature. The authors estimate that the overall error in clinical cumulative dose measurements reported in RAD-IR is 24%.

CONCLUSION

Dosimetric accuracy was well within the tolerances established by IEC standard 60601-2-43. The clinical dose data reported in the RAD-IR study are valid.

Basilar artery herniation into the sphenoid sinus resulting in pontine and cerebellar infarction: demonstration by three-dimensional time-of-flight MR angiography

We report a unique case of basilar artery herniation into the sphenoid sinus caused by a traumatic skull base fracture, with persistent patency of the basilar artery. Clinical and imaging features, as well as the relevant literature, are described.

Temporary balloon occlusion to test adequacy of collateral flow to the retina and tolerance for endovascular aneurysmal coiling

Two carotid ophthalmic artery aneurysms with incorporation of the artery into the neck were referred for endovascular assessment. Temporary balloon occlusion at the aneurysm neck was performed in an attempt to assess the adequacy of collateral flow to the retina. During inflation, the patients reported visual deterioration that resolved upon deflation, which indicates that collateral blood flow was insufficient. The patients were referred for surgical clipping to ensure preservation of the ophthalmic artery.

Intracranial chondrosarcoma: a case report and review of the literature

OBJECTIVE AND IMPORTANCE

Chondrosarcomas rarely occur intracranially away from the skull base. We present a case of a supratentorial dural-based, low-grade classic chondrosarcoma and emphasize salient imaging findings that assist in its diagnosis.

CLINICAL PRESENTATION

A 23-year-old female presented with new onset seizures. Multiple radiographic imaging studies identified a large left frontal mass with radiological findings that suggested the correct diagnosis.

INTERVENTION

The patient underwent a left frontal craniotomy and gross total resection of the lesion and associated dura.

CONCLUSION

Intracranial chondrosarcomas away from the skull based are extremely rare malignancies. As with other extra-axial masses, they often grow to a relatively large size before generating symptoms. Careful analysis of CT, MR, and angiographic imaging characteristics should suggest the correct diagnosis.

Radiation doses in interventional radiology procedures: the RAD-IR study: part II: skin dose

PURPOSE

To determine peak skin dose (PSD), a measure of the likelihood of radiation-induced skin effects, for a variety of common interventional radiology and interventional neuroradiology procedures, and to identify procedures associated with a PSD greater than 2 Gy.

MATERIALS AND METHODS

An observational study was conducted at seven academic medical centers in the United States. Sites prospectively contributed demographic and radiation dose data for subjects undergoing 21 specific procedures in a fluoroscopic suite equipped with built-in dosimetry capability. Comprehensive physics evaluations and periodic consistency checks were performed on each unit to verify the stability and consistency of the dosimeter. Seven of 12 fluoroscopic suites in the study were equipped with skin dose mapping software.

RESULTS

Over a 3-year period, skin dose data were recorded for 800 instances of 21 interventional radiology procedures. Wide variation in PSD was observed for different instances of the same procedure. Some instances of each procedure we studied resulted in a PSD greater than 2 Gy, except for nephrostomy, pulmonary angiography, and inferior vena cava filter placement. Some instances of transjugular intrahepatic portosystemic shunt (TIPS) creation, renal/visceral angioplasty, and angiographic diagnosis and therapy of gastrointestinal hemorrhage produced PSDs greater than 3 Gy. Some instances of hepatic chemoembolization, other tumor embolization, and neuroembolization procedures in the head and spine produced PSDs greater than 5 Gy. In a subset of 709 instances of higher-dose procedures, there was good overall correlation between PSD and cumulative dose (r = 0.86; P <.000001) and between PSD and dose-area-product (r = 0.85, P <.000001), but there was wide variation in these relationships for individual instances.

CONCLUSIONS

There are substantial variations in PSD among instances of the same procedure and among different procedure types. Most of the procedures observed may produce a PSD sufficient to cause deterministic effects in skin. It is suggested that dose data be recorded routinely for TIPS creation, angioplasty in the abdomen or pelvis, all embolization procedures, and especially for head and spine embolization procedures. Measurement or estimation of PSD is the best method for determining the likelihood of radiation-induced skin effects. Skin dose mapping is preferable to a single-point measurement of PSD.