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This Practice Advisory presents a comprehensive and evidence-based set of position statements and recommendations for the use of contrast media in interventional pain procedures. The advisory was established by an international panel of experts under the auspices of 11 multinational and multispecialty organizations based on a comprehensive review of the literature up to December 31, 2019. The advisory discusses the risks of using gadolinium-based contrast agents. These include nephrogenic systemic fibrosis, gadolinium brain deposition/retention, and encephalopathy and death after an unintentional intrathecal gadolinium injection. The advisory provides recommendations on the selection of a specific gadolinium-based contrast agent in patients with renal insufficiency, those who had multiple gadolinium-enhanced magnetic resonance imaging examinations, and in cases of paraspinal injections. Additionally, recommendations are made for patients who have a history of mild, moderate, or severe hypersensitivity reactions to contrast medium.

Surgery is a potentially curative treatment option for patients with medically refractory focal epilepsy. Advanced neuroimaging modalities often improve surgical outcomes by contributing key information during the highly individualized surgical planning process and intraoperative localization. Hence, neuroradiologists play an integral role in the multidisciplinary management team. In this review, we initially present the conceptual background and practical framework of the presurgical evaluation process, including a description of the surgical treatment approaches used for medically refractory focal epilepsy in adults. This background is followed by an overview of the advanced modalities commonly used during the presurgical workup at level IV epilepsy centers, including diffusion imaging techniques, blood oxygenation level-dependent functional MRI (fMRI), PET, SPECT, and subtraction ictal SPECT, and by introductions to 7-T MRI and electrophysiologic techniques including electroencephalography and magnetoencephalography. We also provide illustrative case examples of multimodal neuroimaging including PET/MRI, PET/MRI-diffusion-tensor imaging (DTI), subtraction ictal SPECT, and image-guided stereotactic planning with fMRI-DTI.

BackgroundDisease-modifying anti-rheumatic drugs (DMARDs) are used in the management of rheumatoid arthritis (RA) and are classified as conventional DMARDs and biologic agents. A concern with DMARDs is the increased risk of infection after surgery. A practice advisory from the American Society of Anesthesiologists recommend alternatives to neuraxial injections in patients who are immunocompromized. We describe a patient who was on several DMARDs and developed inflammatory reactions in her bilateral paraspinal muscles and lumbar spine after an epidural steroid injection (ESI).Case presentationThe patient was a 79-year-old woman; she was taking methotrexate, adalimumab and prednisone for her RA. She had a left L5-S1 paramedian ESI for her L5 radiculitis. After relief of her back and radicular pain for 5 weeks, she had an acute exacerbation of her back pain. MRI showed bilateral paraspinal fluid accumulations and enhancement in her ligamentum flavum. Cultures of the aspirated fluid and biopsy specimens were negative for fungal, aerobic and anaerobic organisms. A repeat MRI 2 months later showed diminution of the fluid collection but with a new fluid accumulation near the left L4-5 facet and left L4 pedicle. Repeat cultures and gram stain of the specimens taken from the pedicle and the paraspinal muscles were negative. The patient was followed by her rheumatologist and in the pain clinic until resolution of her symptoms.ConclusionsSeveral society guidelines recommend the continuation of methotrexate but stoppage of the biologic DMARDS before surgery. The occurrence of an intense inflammatory reaction after an ESI in our patient calls for additional research on the subject and shared decision-making between the pain physician, patient and rheumatologist especially in patients on several DMARDs.

To evaluate the effect of hepatic metastatic lesion size on inter-reader reproducibility of CT-based 2D radiomics imaging features.Computerized tomography (CT) scans of 59 liver metastases from 34 patients with colorectal cancer were evaluated. Image segmentation was performed manually by three readers blinded to each other's results. For each radiomics feature, we created two datasets by sorting measurements according to size, i.e., (i) from the smallest to the largest lesion and (ii) from the largest to the smallest lesion. The Lin concordance correlation coefficient (CCC) was employed to analyze the reproducibility of radiomics features. In particular, the CCC was computed as a function of a number of elements in the dataset, by gradually adding lesions from each sorted dataset. To evaluate the effect of lesion size, we analyzed the difference between these two functions thus assessing the contribution of small and large lesions into the reproducibility of radiomics features.Inter-reader reproducibility of CT-based 2D radiomics features assessed using Lin's CCC demonstrates tumor-size dependence. For example, the Lin CCC for GLCM contrast equals 0.88 (95% C.I. 0.84 to 0.92, p 0.003) and could change by an additional + / - 0.06 depending on the presence of large or small lesions.Groups of "large" and "small" lesions show different inter-reader reproducibility. The inter-reader reproducibility from the mixed group consisting of "large" and "small" lesions depends on the lesion-size distribution and can vary widely. This finding could partially explain variability in reproducibility of radiomics features in the literature.• Groups of "large" and "small" lesions show different inter-reader reproducibility. • The inter-reader reproducibility from the mixed group consisting of "large" and "small" lesions depends on the lesion-size distribution.

BACKGROUND. Gadobutrol and gadoterate are widely used macrocyclic gadolinium-based contrast agents. Given gadobutrol's higher T1 relaxivity, a reduced gadobutrol dose should achieve essentially equivalent diagnostic efficacy as a standard dose of gadoterate. OBJECTIVE. The purpose of our study was to show efficacy of a 25% reduced dose of gadobutrol is noninferior to 100% standard dose of gadoterate for contrast-enhanced MRI of the CNS. METHODS. In this international prospective multicenter open-label crossover trial (LEADER-75 [Lower Administered Dose With Higher Relaxivity: Gadovist vs Dotarem]), adult patients with known or suspected CNS pathology underwent contrast-enhanced brain MRI with standard-dose gadoterate (0.1 mmol/kg); if an enhancing lesion was identified, a second MRI with reduced-dose gadobutrol (0.075 mmol/kg) was performed within 15 days of the first MRI. Three radiologists independently reviewed images to score three primary efficacy measures: subjective lesion enhancement, lesion border delineation, lesion internal morphology. A noninferiority analysis used readers' mean scores of the primary efficacy measures. Noninferiority of reduced-dose gadobutrol to standard-dose gadoterate for primary efficacy measures was defined as the difference in score between reduced-dose gadobutrol images and unenhanced images achieving at least 80% of the difference in score between standard-dose gadoterate images and unenhanced images. A post hoc analysis was performed to directly compare contrast-enhanced images for equivalence. Secondary efficacy variables included the number of lesions detected, reader confidence, diagnostic performance for malignancy, and reader preference in side-by-side comparison. RESULTS. The efficacy analysis included 141 patients (78 men, 63 women; mean age, 58.5 ± 13.5 [SD] years). Improvement of reduced-dose gadobutrol over unenhanced images was noninferior to improvement of standard-dose gadoterate over unenhanced images using a 20% noninferiority margin for all three primary efficacy measures using mean readings (p ≤ .025). In the post hoc analysis, the mean reading for the three primary efficacy measures differed by less than 1% between reduced-dose gadobutrol and standard-dose gadoterate, supporting equivalence of all measures using a narrow ± 5% margin (p ≤ .025). The total number of lesions detected by mean reading was 301 for reduced-dose gadobutrol versus 291 for standard-dose gadoterate. Mean reader confidence was 3.3 ± 0.6 for reduced-dose gadobutrol versus 3.3 ± 0.6 for standard-dose gadoterate. Sensitivity (58.7%), specificity (91.8%), and accuracy (70.2%) for malignancy from majority reading were identical for reduced-dose gadobutrol and standard-dose gadoterate. Reader preference was not different (95% CI, -0.10 to 0.11). CONCLUSION. A 25% reduced dose of gadobutrol is noninferior to standard-dose gadoterate for contrast-enhanced brain MRI. CLINICAL IMPACT. Use of reduced-dose gadobutrol should be considered for brain MRI, particularly in patients undergoing multiple contrast-enhanced examinations. TRIAL REGISTRATION. ClinicalTrials.gov NCT03602339; EU Clinical Trials Register EudraCT 2018-00690-78.

Functional MR imaging is being performed with increasing frequency in the typical neuroradiology practice; however, many readers of these studies have only a limited knowledge of the functional anatomy of the brain. This text will delineate the locations, anatomic boundaries, and functions of the cortical regions of the brain most commonly encountered in clinical practice-specifically, the regions involved in movement and language.

In patients with a history of a hypersensitivity reaction to iodinated contrast medium, iodinated contrast medium is avoided, antihistamine and steroid premedication are given, or a gadolinium-based contrast agent is employed. Six patients with a history of a hypersensitivity reaction to iodinated contrast medium and who were not premedicated had an unintentional injection of iodinated contrast. None of the patients developed a moderate or severe reaction. All patients had gadopentetate dimeglumine in one of their injections; three had repeated injections of the gadopentetate. The lack of a significant reaction may be due to any or all of the following: questionable history of iodinated contrast reaction, low dose of iodinated contrast given, concomitant injection of (epidural) steroid, and slower absorption from epidural compared with intravenous injection. While it is reassuring to know that there is a low possibility of a moderate to severe reaction in these patients, every effort should be made to avoid this scenario, appropriate drugs and resuscitation equipment should be immediately available, and the patients should be observed adequately and followed for the possibility of late reactions. Recent publications have called for caution in the use of gadolinium-based contrast agents.

2016 Background: The blood-brain barrier (BBB) is a major impediment to pharmacological treatment of gliomas, a diffuse tumor infiltrating the peri-tumoral normal brain. Low-intensity pulsed ultrasound directed at the brain with concomitant administration of intravenous microbubbles (LIPU/MB), temporarily opens the BBB. This technique was previously shown with a first generation of the device in combination with carboplatin chemotherapy (Idbaih et al. 2019). Here we investigate the pharmacokinetics and safety of this approach in the context of repeated delivery of albumin-bound paclitaxel (ABX) to the peri-tumoral brain. To perform LIPU/MB-based BBB opening prior to ABX infusions, we used a novel 6 x 6 cm device with 9 ultrasound emitters (SC9) that is implanted in a skull window after tumor resection. Methods: A Phase 1 dose-escalation trial using Bayesian adaptive design was initiated at our institution (NCT04528680). Patients with recurrent operable glioblastoma, a WHO PS ≤ 2 and normal bone marrow and organ function were eligible. After tumor resection and implantation of SC9, repeated cycles of BBB opening by LIPU/MB immediately followed by ABX, was performed every 3 weeks. Intraoperative LIPU/MB and low dose ABX was given prior to tumor resection for investigation of pharmacokinetics. Results: Seventeen patients have been enrolled and six dose levels of ABX were used (40-260 mg/m2). Severe, reversible taxane-associated encephalopathy was observed in one patient at the max. planned dose level (260 mg/m2). The patient continued treatment at a lower dose in subsequent cycles. One patient developed grade 2 cumulative peripheral neuropathy. Other mild to moderate and reversible toxicities for ABX including myelosuppression, fatigue, alopecia were observed as expected. Intraoperative sonication and pharmacokinetic studies showed that ABX tissue concentrations in non-enhancing peri-tumoral brain were increased several-fold after LIPU/MB. On electron microscopy, sonicated tissue showed ultra-structural alterations in brain capillary endothelial cells. Molecular studies showed transcriptional dysregulation of membrane transporters, pathways related to trans-cytosis, cell permeability as well as cell-cell and cell-matrix adhesion. Updated results will be presented. Conclusions: The LIPU/MB using skull-implantable ultrasound enhances the penetration of large chemotherapeutic drugs such as ABX in large regions of the brain, a procedure that can be performed repeatedly and safely. LIPU-based BBB opening leads to ultrastructural and transcriptional alterations in brain endothelial cells. A Phase 2 clinical trial is planned to investigate efficacy of this approach. Funding: NIH/NCI 1R01CA245969-01A1, Carthera (SC9 devices), Celgene/BMS, Malnati Brain Tumor Institute, Moceri Family Foundation. Clinical trial information: NCT04528680.

Objectives The aim of this study was to determine a safe and effective dose of gadopiclenol, a new high relaxivity macrocyclic gadolinium-based contrast agent. Based on the contrast-to-noise ratio (CNR) as primary criterion, this new agent was compared with gadobenate dimeglumine in patients with contrast-enhancing central nervous system lesions. Methods and materials This phase IIb international, multicenter, double-blind, randomized, controlled, parallel dose groups, and cross-over study included adult patients with known or highly suspected lesions with disrupted blood-brain barrier. Patients were randomized to 1 of 4 doses of gadopiclenol (0.025, 0.05, 0.1, 0.2 mmol/kg) and to 1 series of 2 magnetic resonance imaging scans: gadopiclenol then gadobenate dimeglumine at 0.1 mmol/kg or vice versa. The qualitative and quantitative efficacy evaluations were performed by 3 independent off-site blinded readers. Adverse events were monitored up to 1 day after second magnetic resonance imaging. Results The study population included 272 patients (58.5% females) with a mean (SD) age of 53.8 (13.6) years. The superiority of gadopiclenol over gadobenate dimeglumine was statistically demonstrated at 0.2 and 0.1 mmol/kg for all readers with an increase in CNR of more than 30% (P ≤ 0.0007). At 0.05 mmol/kg, gadopiclenol showed a CNR of similar magnitude as gadobenate dimeglumine at 0.1 mmol/kg, with no statistically significant difference. Similar results were obtained for lesion-to-brain ratio and contrast enhancement percentage, as secondary criteria. The relationship between CNR and dose of gadopiclenol was linear for all readers. Mean scores for lesion visualization variables, particularly lesion contrast enhancement, tended to be higher with gadopiclenol at 0.1 and 0.2 mmol/kg compared with gadobenate dimeglumine. All 3 readers mainly expressed an overall diagnostic preference for images with gadopiclenol at 0.1 mmol/kg (45.3%, 50.9%, or 86.8% of images) or expressed no preference (49.1%, 49.1%, or 9.4%, respectively), whereas preference for images with gadobenate dimeglumine was reported by 2 readers for 3.8% and 5.7% of the images. Predominantly, no preference was expressed when comparing images with gadopiclenol at 0.05 mmol/kg to those with gadobenate dimeglumine.Rates of adverse reactions were comparable for gadopiclenol (11.7%) and gadobenate dimeglumine (12.1%). Changes from baseline of more than 25% in serum creatinine and estimated glomerular filtration rate occurred in less than 2% of patients equally for gadopiclenol and gadobenate dimeglumine. Changes from baseline for the values of blood urea nitrogen and cystatin C were also similar between gadopiclenol and gadobenate dimeglumine. No safety concerns were detected on centralized electrocardiography readings. Conclusions Between the doses of 0.025 and 0.2 mmol/kg of gadopiclenol, the increase in CNR is linear. Compared with gadobenate dimeglumine at 0.1 mmol/kg, the doses of 0.05 and 0.1 mmol/kg of gadopiclenol gave similar or significantly greater contrast enhancement, respectively, and thus both doses can be considered for future phase III studies.

There are two neuron-level mechanisms proposed to underlie neural plasticity: recruiting neurons nearby to support the lost function (ipsilesional plasticity) and uncovering latent pathways that can assume the function that was lost (contralesional plasticity). While both patterns have been demonstrated in patient groups following injury, the specific mechanisms underlying each mode of plasticity are poorly understood. In a retrospective case series of 13 patients, we utilize a novel paradigm that analyzes serial fMRI scans in patients harboring intrinsic brain tumors that vary in location and growth kinetics to better understand the mechanisms underlying these two modes of plasticity in the human primary motor cortex. Twelve patients in our series had some degree of primary motor cortex plasticity, an area previously thought to have limited plasticity. Patients harboring smaller lesions with slower growth kinetics and increasing distance from the primary motor region demonstrated recruitment of ipsilateral motor regions. Conversely, larger, faster-growing lesions in close proximity to the primary motor region were associated with activation of the contralesional primary motor cortex, along with increased activation of the supplementary motor area. These data increase our understanding of the adaptive abilities of the brain and may lead to improved treatment strategies for those suffering from motor loss secondary to brain injuries.

BACKGROUND: Among diffusely infiltrative gliomas in adults, 20%–30% contain a point mutation in isocitrate dehydrogenase 1 (IDH1(mut)), which increases production of D-2-hydroxyglutarate (D2HG). This is so efficient that D2HG often reaches 30 mM within IDH1(mut) gliomas. Yet, while up to 100 µM D2HG can be detected in the circulating cerebrospinal fluid of IDH1(mut) glioma patients, the exposure of nonneoplastic cells within and surrounding an IDH1(mut) glioma to D2HG is unknown and difficult to measure directly. METHODS: Conditioned medium from patient-derived wild type IDH1 (IDH1(wt)) and IDH1(mut) glioma cells was analyzed for D2HG by liquid chromatography–mass spectrometry (LC-MS). Mathematical models of D2HG release and diffusion around an IDH1(mut) glioma were independently generated based on fluid dynamics within the brain and on previously reported intratumoral and cerebrospinal D2HG concentrations. RESULTS: LC-MS analysis indicates that patient-derived IDH1(mut) glioma cells release 3.7–97.0 pg D2HG per cell per week. Extrapolating this to an average-sized tumor (30 mL glioma volume and 1 × 10(8) cells/mL tumor), the rate of D2HG release by an IDH1(mut) glioma (S(A)) is estimated at 3.2–83.0 × 10(−12) mol/mL/sec. Mathematical models estimate an S(A) of 2.9–12.9 × 10(−12) mol/mL/sec, within the range of the in vitro LC-MS data. In even the most conservative of these models, the extracellular concentration of D2HG exceeds 3 mM within a 2 cm radius from the center of an IDH1(mut) glioma. CONCLUSIONS: The microenvironment of an IDH1(mut) glioma is likely being exposed to high concentrations of D2HG, in the low millimolar range. This has implications for understanding how D2HG affects nonneoplastic cells in an IDH1(mut) glioma.

As physician extenders (PEs) enter the medical community in large numbers, they have an increasing impact on imaging utilization and imaging-based procedures. Physician assistants (PAs) and nurse practitioners (NPs) have an advanced level of education and some practice autonomously. However, PA and NP programs are not required to provide any basic radiology education. For PEs who did receive basic radiology education during their graduate program, the curriculum is nonstandard and there is a wide variation. PEs working in primary care and nonradiology specialties place imaging orders, review report findings, and answer patient questions. Other PEs working within radiology practices operate as liaisons with patients in diagnostic radiology or perform an increasing number of interventional procedures. Basic radiology education in formal PE certificate programs as well as on-the-job education about radiology may benefit patients, radiologists, and the health-care system. What role, if any, should the radiologist assume for educating PE students and practicing PAs and NPs? This review analyzes the benefits and drawbacks of radiologists educating PEs.

We appreciate the comments of Kalangara and Kuruvilla and Boehm.[1 2][1] In our paper, we discussed the topics that Kalangara and Kuruvilla elucidated on. These included switching to a different non-ionic contrast medium and the controversies regarding skin testing and premedication. Kalangara and

Approximately 20-30% of diffusely infiltrative gliomas in adults contain a point mutation in isocitrate dehydrogenase 1 (IDH1mut), which leads to production of D-2-hydroxyglutarate (D2HG). Production of D2HG is so efficient that D2HG concentrations often reach 30 mM within IDH1mut gliomas. Yet, while up to 100 µM D2HG can be detected in the circulating cerebrospinal fluid of IDH1mut glioma patients, the amount of D2HG to which nonneoplastic cells are exposed within and surrounding an IDH1mut glioma is unknown and difficult to measure directly in patients or animal models. Thus, to date, the majority of research on D2HG has focused on its effects inside tumor cells, with very little known about its role in the tumor microenvironment. Liquid chromatography-mass spectrometry (LC-MS) analysis indicates that patient-derived IDH1mut glioma cells release approximately 3.7-6.7 pg D2HG per cell per week in culture. Extrapolating this to an average-sized tumor (30 ml glioma volume and 1x108 cells/ml tumor, the latter based on a previously published estimate of tumor cell density), the rate of D2HG release by an IDH1mut glioma (SA) is calculated to be 3.2-5.8x10-12 moles/ml/sec. Mathematical models of D2HG production and diffusion around an IDH1mut glioma were independently generated based on intracerebral fluid dynamics and previously reported D2HG concentrations in the cerebrospinal fluid. These models estimate an SA of 2.9-17.0x10-12 moles/ml/sec, in good agreement with the LC-MS data generated from in vitro models. In even the most conservative of these diffusion models, the extracellular concentration of D2HG exceeds 3 mM within a 2 cm radius from the center of an IDH1mut glioma. This has profound implications for understanding how D2HG may alter the microenvironmental landscape in IDH1mut gliomas.

When deciding to perform imaging for headache, it is important to consider many factors including the pretest probability, prevalence of diseases, sensitivity of imaging, and implications for treatment. For the first presentation of a headache or a change in headache pattern, if the characteristics do not perfectly fit a primary headache type, imaging may be indicated according to the ICHD-2 criteria to exclude a secondary cause before a primary headache is diagnosed. The value of negative imaging should not be underestimated in the cost-benefit analysis, which often only takes into account number needed to treat or likelihood of finding a significant treatable abnormality. One study has shown that some groups of patients are less likely to overuse other parts of the health care system after negative neuroimaging. Further studies with stronger methodologies, finer differentiation of acute and chronic headache presentations, more advanced imaging technology, among other factors, can improve decision making on when to use imaging and assess the impact of imaging on patient satisfaction and quality of life. In addition, functional MRI, MRS, and voxel-based morphometry MRI are only some of the neuroimaging techniques currently used in research to further understand the pathophysiology and mechanisms of headache. In conclusion, although most headaches are a primary headache disorder with a benign course, imaging is an important part of the diagnostic evaluation to exclude the presence of a secondary cause of headache that could cause fatal results or severe neurologic morbidity. In headache patients without focal neurologic examination abnormalities, the yield of neuroimaging for significant intracranial findings is generally low. However, specific subgroups of headache patients and headache presentations can have much higher rates of significant intracranial abnormalities.

As physician extenders (PEs) enter the medical community in large numbers, they have an increasing impact on imaging utilization and imaging-based procedures. Physician assistants (PAs) and nurse practitioners (NPs) have an advanced level of education and some practice autonomously. However, PA and NP programs are not required to provide any basic radiology education. For PEs who did receive basic radiology education during their graduate program, the curriculum is nonstandard and there is a wide variation. PEs working in primary care and nonradiology specialties place imaging orders, review report findings, and answer patient questions. Other PEs working within radiology practices operate as liaisons with patients in diagnostic radiology or perform an increasing number of interventional procedures. Basic radiology education in formal PE certificate programs as well as on-the-job education about radiology may benefit patients, radiologists, and the health-care system. What role, if any, should the radiologist assume for educating PE students and practicing PAs and NPs? This review analyzes the benefits and drawbacks of radiologists educating PEs.

Objectives This study aims to report tumor control rates and cranial nerve function after low dose (11.0 Gy) Gamma knife radiosurgery (GKRS) in patients with vestibular schwannomas. Methods A retrospective chart review was performed on 30 consecutive patients with vestibular schwannomas treated from March 2004 to August 2010 with GKRS at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University. The marginal dose for all patients was 11.0 Gy prescribed to the 50% isodose line. Median follow-up time was 42 months. The median treatment volume was 0.53 cm 3 . Hearing data were obtained from audiometry reports before and after radiosurgery. Results The actuarial progression free survival (PFS) based on freedom from surgery was 100% at 5 years. PFS based on freedom from persistent growth was 91% at 5 years. One patient experienced tumor progression requiring resection at 87 months. Serviceable hearing, defined as Gardner–Robertson score of I–II, was preserved in 50% of patients. On univariate and multivariate analyses, only higher mean and maximum dose to the cochlea significantly decreased the proportion of patients with serviceable hearing. Conclusion Vestibular schwannomas can be treated with low doses (11.0 Gy) of GKRS with good tumor control and cranial nerve preservation.

The authors describe a case of intracranial vascular calcifications that mimicked small saccular aneurysms on CT angiography (CTA). The density of two vascular calcifications was visually similar to that of contrast in the parent vessel, making them indistinguishable from aneurysmal outpouchings. Comparison of the CTA with the non-contrast head CT (NCCT) was critical to distinguish low-density calcifications from tiny aneurysms.

Gonadotropin analogs like leuprolide play an important role in the management of prostate cancer. Pituitary apoplexy has been reported after leuprolide therapy. This report examines whether the presence of a pituitary tumor is a contraindication for leuprolide therapy in patients with prostate cancer. Two patients with prostate cancer and pituitary tumors were treated with leuprolide and radiation therapy. The first patient with a previously unknown pituitary adenoma had a leuprolide injection for prostate gland downsizing prior to brachytherapy. The second patient with a known pituitary microadenoma had a biochemical recurrence and was treated with leuprolide and radiation therapy. The first patient developed symptoms of apoplexy a few hours after the leuprolide injection. He underwent a transsphenoidal resection of the sellar mass with complete neurologic recovery. The second patient did not have any adverse events after leuprolide with follow-up MRI scans showing no growth of the microadenomas. The presence of a pituitary tumor is not a contraindication for leuprolide therapy. While patients with a macroadenoma should have surgery first, those with a microadenoma may be considered for leuprolide therapy after careful evaluation by a multidisciplinary team.

A novel transosseous approach for percutaneous access of the lumbar subarachnoid space is described in a patient with advanced ankylosing spondylitis (AS) and instrumented spinal fusion who presented for myelography. Use of a coaxial threaded bone biopsy system to provide transosseous access to the thecal sac, imaging findings, and outcome are discussed. This technique provided access to an otherwise inaccessible subarachnoid space and is an alternative approach in the setting of advanced AS or posterior spinal fusion.

The association between sensorineural hearing loss and sickle cell disease has been described, and labyrinthine hemorrhage has been reported with sickle cell disease. We report the CT and MRI findings of labyrinthitis ossificans in a child with sickle cell disease who presented with sensorineural hearing loss. Labyrinthitis ossificans is associated with an infectious, inflammatory, or destructive insult to the membranous labyrinth; however, it has not been specifically described with sickle cell disease. Recognition of this condition is important because it affects both management and prognosis of this disease.

A 52-year-old man with burn injuries and prolonged intubation developed PGS with hoarseness, dyspnea, and bilateral vocal cord immobility. On CT, a calcified interarytenoid scar band was identified, corresponding to an interarytenoid scar on laryngoscopy. Endoscopic laser lysis of the calcified scar band relieved the symptoms. We present laryngoscopic and CT findings of PGS with interarytenoid calcification along with the postlysis findings. The classification, clinical findings, imaging, and management of PGS are reviewed.

Summary: We report the use of CT angiography in the diagnosis and preoperative planning of a superficial temporal artery pseudoaneurysm. A 50-year-old man presented with a pulsatile preauricular mass 4 weeks after undergoing pterional craniotomy for aneurysm repair. CT angiography revealed a 2.5-cm pseudoaneurysm arising from the posterior margin of the right superficial temporal artery at the inferior margin of the craniotomy incision. To our knowledge, this is the first reported case showing the usefulness of CT angiography alone in the diagnosis and characterization of a superficial temporal artery pseudoaneurysm.

This study investigates the distribution of ventilation-perfusion (V/Q) signal intensity (SI) ratios using oxygen-enhanced and arterial spin labeling (ASL) techniques in the lungs of 10 healthy volunteers. Ventilation and perfusion images were simultaneously acquired using the flow-sensitive alternating inversion recovery (FAIR) method as volunteers alternately inhaled room air and 100% oxygen. Images of the T(1) distribution were calculated for five volunteers for both selective (T(1f)) and nonselective (T(1)) inversion. The average T(1) was 1360 ms +/- 116 ms, and the average T(1f) was 1012 ms +/- 112 ms, yielding a difference that is statistically significant (P < 0.002). Excluding large pulmonary vessels, the average V/Q SI ratios were 0.355 +/- 0.073 for the left lung and 0.371 +/- 0.093 for the right lung, which are in agreement with the theoretical V/Q SI ratio. Plots of the V/Q SI ratio are similar to the logarithmic normal distribution obtained by multiple inert gas elimination techniques, with a range of ratios matching ventilation and perfusion. This MRI V/Q technique is completely noninvasive and does not involve ionized radiation. A limitation of this method is the nonsimultaneous acquisition of perfusion and ventilation data, with oxygen administered only for the ventilation data.

Purpose To investigate the optimal oxygen flow rate for oxygen-enhanced MR ventilation imaging. Materials and Methods Using a cardiac-triggered nonselective inversion recovery (IR) half Fourier single-shot fast spin echo sequence, series of images were acquired with the subject alternately inhaling room air and 100% oxygen. Oxygen flow rates of 5 L/min, 10 L/min, 15 L/min, 20 L/min, and 25 L/min were studied, and signal intensity from the oxygen-enhanced ventilation images and T1 of the lung were measured. Results The average signal intensity was 63.0 ± 21.0 for 5 L/min, 98.7 ± 26.8 for 10 L/min, 133.8 ± 20.0 for 15 L/min, 138.7 ± 19.7 for 20 L/min, and 139.2 ± 37.9 for 25 L/min. The average T1's of the lung were 1399 msec ± 130 msec for room air, 1314 msec ± 101 msec for 5 L/min, 1276 msec ± 105 msec for 10 L/min, 1207 msec ± 71 msec for 15 L/min, 1206 msec ± 90 msec for 20 L/min, and 1207 msec ± 42 msec for 25 L/min. Conclusion The optimal flow rate is 15 L/min for oxygen-enhanced ventilation imaging. J. Magn. Reson. Imaging 2002;16:37–41. © 2002 Wiley-Liss, Inc.

We read with interest the letter by Lee et al describing a case of postoperative superficial temporal artery pseudoaneurysm.1 Although we agree that this complication is rare, we do not agree with their statement, “such a complication after cranial surgery has not previously been reported”. …