Use of a Commercial 7-T MRI Scanner for Clinical Brain Imaging: Indications, Protocols, Challenges, and Solutions-A Single-Center Experience.

The first commercially available 7-T MRI scanner (Magnetom Terra) was approved by the FDA in 2017 for clinical imaging of the brain and knee. After initial protocol development and sequence optimization efforts in volunteers, the 7-T system, in combination with an FDA-approved 1-channel transmit/32-channel receive array head coil, can now be routinely used for clinical brain MRI examinations. The ultrahigh field strength of 7-T MRI has the advantages of improved spatial resolution, increased SNR, and increased CNR but also introduces an array of new technical challenges. The purpose of this article is to describe an institutional experience with the use of the commercially available 7-T MRI scanner for routine clinical brain imaging. Specific clinical indications for which 7-T MRI may be useful for brain imaging include brain tumor evaluation with possible perfusion imaging and/or spectroscopy, radiotherapy planning; evaluation of multiple sclerosis and other demyelinating diseases, evaluation of Parkinson disease and guidance of deep brain stimulator placement, high-detail intracranial MRA and vessel wall imaging, evaluation of pituitary pathology, and evaluation of epilepsy. Detailed protocols, including sequence parameters, for these various indications are presented, and implementation challenges (including artifacts, safety, and side effects) and potential solutions are explored.

Probabilistic tractography of the extracranial branches of the trigeminal nerve using diffusion tensor imaging.

PURPOSE: The peripheral course of the trigeminal nerves is complex and spans multiple bony foramen and tissue compartments throughout the face. Diffusion tensor imaging of these nerves is difficult due to the complex tissue interfaces and relatively low MR signal. The purpose of this work is to develop a method for reliable diffusion tensor imaging-based fiber tracking of the peripheral branches of the trigeminal nerve. METHODS: We prospectively acquired imaging data from six healthy adult participants with a 3.0-Tesla system, including T2-weighted short tau inversion recovery with variable flip angle (T2-STIR-SPACE) and readout segmented echo planar diffusion weighted imaging sequences. Probabilistic tractography of the ophthalmic, infraorbital, lingual, and inferior alveolar nerves was performed manually and assessed by two observers who determined whether the fiber tracts reached defined anatomical landmarks using the T2-STIR-SPACE volume. RESULTS: All nerves in all subjects were tracked beyond the trigeminal ganglion. Tracts in the inferior alveolar and ophthalmic nerve exhibited the strongest signal and most consistently reached the most distal landmark (58% and 67%, respectively). All tracts of the inferior alveolar and ophthalmic nerve extended beyond their respective third benchmarks. Tracts of the infraorbital nerve and lingual nerve were comparably lower-signal and did not consistently reach the furthest benchmarks (9% and 17%, respectively). CONCLUSION: This work demonstrates a method for consistently identifying and tracking the major nerve branches of the trigeminal nerve with diffusion tensor imaging.

Stability of serial platelet and urine protein measurements in patients receiving nusinersen for spinal muscular atrophy.

INTRODUCTION/AIMS: Patients undergoing nusinersen treatment for spinal muscular atrophy are subject to measurements of platelet count and urine protein before each injection due to concern for platelet depletion and renal dysfunction according to the prescribing information. These tests may be uncomfortable or inconvenient and may cause delays in treatment. However, it is still unclear whether these values have been significantly affected by nusinersen treatment. Our aim in this study was to determine whether these measurements ever reached critical values that necessitated withholding treatment at our center. METHODS: Records from 57 patients treated with nusinersen at our institution between 2017 and 2020 were retrospectively analyzed. Laboratory values for platelet count, random urine protein, and total urine protein:creatinine ratio were collected from all patients before each procedure. RESULTS: Mean patient age was 28.9 years (range, 2-76 years). Mean platelet count was 307 × 109 /L (range, 96-755 × 109 /L; normal lab limits, 150-450 × 109 /L), mean random urine protein was 0.164 g/L (range, <0.05-0.73 g/L), and mean total urine protein:creatinine ratio was 0.885 g per gram creatinine (range, 0.12-9.71 g per gram creatinine). No laboratory values precluded continuing treatment for any patient. DISCUSSION: Although further study on a larger cohort is warranted for more definitive conclusions, it may not be necessary to measure platelet count and urine protein before each nusinersen treatment, particularly in the maintenance phase.

Torcular pseudomass in newborns and its association with delivery: follow up or leave it alone?

PURPOSE: The cranial epidural space (ES) is a potential space and is not generally recognized unless there is underlying pathology. With MRI in newborns, we have frequently observed T2 hyperintense thickening of the ES posterior to the confluence of sinuses, also referred to as "torcular pseudomass" (TP). We aim to identify the frequency of TP and possible associations with delivery. METHODS: Retrospectively, brain MRIs of 194 neonates obtained within the first 2 weeks of life were evaluated. If TP was present, imaging characteristics and thickness were assessed by two observers, using fat-suppressed T2WI/FLAIR, T1WI, and SWI. Exclusion criteria were motion artifact, lack of sagittal T2WI, and lack of clinical data. Medical records were evaluated for demographic and clinical data. Follow-up exams were evaluated if available. Patients with TP and without were compared using Student t and chi-square tests. RESULTS: TP was present in 64/158 (40%). No difference was found between the groups regarding sex, gestational age, birth weight, delivery type, fetal presentation during delivery, birth difficulty, and neurological sequelae (p > 0.05). Eight patients with TP underwent follow-up imaging, and in 6/8, TP completely resolved. Two patients showed persistent TP, improving from 3.2 to 1 mm in one child and from 3.2 to 2.8 mm in the other within a week. CONCLUSION: TP frequently occurs in early newborns. TP does not appear to be associated with factors related to delivery, shows complete resolution in most cases with a follow-up, and is likely of no clinical importance.

A common yet undescribed MRI finding in newborns: posterior epidural space edema of the cervical and upper thoracic spine.

PURPOSE: Posterior spinal epidural space (PSES) is a fat-containing space. We noted numerous spinal MRIs demonstrating T2-hyperintense thickening of the cervical/thoracic PSES in early newborns, resembling epidural edema. Our aim is to describe the appearance/frequency of this finding and explore any associations with delivery. METHODS: Retrospectively, 202 spinal/cranial MRIs, belonging to newborns within the first 2 weeks of life, were evaluated using sagittal fat-suppressed T2, T1-FLAIR, and STIR. Exclusion criteria were motion, incomplete spine imaging, lack of sagittal T2/STIR, and inadequate clinical data. Ninety-three patients were included in the final analysis. We reviewed all cases for T2 hyperintense thickened PSES and, if present, accompanying abnormal T1 signal. The spinal canal and PSES thickness were measured. Clinical and demographic data were collected. Follow-up exams were evaluated, if available. Cases with thickened PSES and without were compared. RESULTS: T2-hyperintense thickened PSES was present in 60/93 (64.5%). Mean PSES thickness was 2.3 mm (0.7-4.6). The mean PSES thickness/spinal canal diameter ratio was 0.2 (0.1-0.5). No cord compression was identified. One had a hyperintense T1 PSES signal, compatible with epidural hemorrhage. No difference was found between those with thickened PSES and without, regarding sex, gestational age, birth weight, birth method, difficult delivery, fetal position, or neurologic status (p>0.05). Follow-up imaging was available in 10, with complete resolution of T2 hyperintense PSES thickening. CONCLUSION: T2 hyperintense PSES thickening is common in imaged newborns and reversible at follow-up. No significant neurologic outcomes were found related to its presence; thus, follow-up does not appear necessary.

Lymphadenopathy in COVID-19 Vaccine Recipients: Diagnostic Dilemma in Oncologic Patients.

Five cases of axillary lymphadenopathy are presented, which occurred after COVID-19 vaccination and mimicked metastasis in a vulnerable oncologic patient group. Initial radiologic diagnosis raised concerns for metastasis. However, further investigation revealed that patients received COVID-19 vaccinations in the ipsilateral arm prior to imaging. In two cases, lymph node biopsy results confirmed vaccination-related reactive lymphadenopathy. Ipsilateral axillary swelling or lymphadenopathy was reported based on symptoms and physical examination in COVID-19 vaccine trials. Knowledge of the potential for COVID-19 vaccine-related ipsilateral adenopathy is necessary to avoid unnecessary biopsy and change in therapy. © RSNA, 2021.

Impact of 18-French Rectal Tube Placement on Image Quality of Multiparametric Prostate MRI.

This study compared prostate multiparametric MRI (mpMRI) performed using an 18-French rectal tube in place throughout the examination after initial placement by a technologist (n = 97) with mpMRI performed without rectal tube placement (n = 99). Acquisition parameters were otherwise identical. Two radiologists scored subjective image quality and measured rectal diameter. For both readers, rectal tube placement was associated (p < .001) with improved ADC map quality, decreased DWI distortion, decreased rectal gas, and decreased rectal diameter. Findings support routine rectal tube placement for prostate mpMRI.

The Role of Dual-Phase FDG PET/CT in the Diagnosis and Follow-Up of Brain Tumors.

OBJECTIVE. FDG PET/CT of brain tumors is limited by background activity. Dual-phase FDG PET/CT can eliminate this limitation and allow discernment of viable tumors. Our aim was to assess the diagnostic capability of dual-phase FDG PET/CT qualitatively and quantitatively and to determine cutoff values for dual-phase FDG PET/CT in brain tumor imaging. MATERIALS AND METHODS. Retrospectively, 51 malignant brain tumors were evaluated with dual-phase FDG PET/CT in 32 patients. Acquisitions were performed 30 minutes (time 1) and 3 hours (time 2) after administration of 10 mCi (370 MBq) FDG and 6 hours of fasting. Two observers independently and qualitatively evaluated lesions. A weighted Cohen kappa was used to calculate interrater reliability and accuracy. Quantitatively, maximum standardized uptake value (SUVmax) was measured in the lesions, contralateral white matter (CWM), contralateral caudate nucleus head, and ipsilateral cerebellar cortex (CC). Lesion-to-CWM SUVmax, lesion-to-contralateral caudate nucleus head SUVmax, and lesion-to-ipsilateral CC SUVmax ratios at time 1 and time 2 were calculated. ROC analysis was used to determine optimum cutoff values, and AUC ratios were compared among quantitative parameters. Lesion outcome was determined by pathologic results (available in 15 lesions), lesion stability on serial MRI examinations (representing nonviable tumor), or decreased tumor size on serial MRI examinations after new treatment (representing viable tumor). RESULTS. Thirty-seven viable and 14 nonviable lesions were evaluated. Qualitatively, the diagnostic accuracy (first observer: κ = 0.45 to κ = 0.59; second observer: κ = 0.41 to κ = 0.66) and interrater reliability (at time 1: κ = 0.51; at time 2: κ = 0.83) improved with delayed imaging. AUC and ROC analysis showed comparably high sensitivity, specificity, and accuracy profiles for early and delayed dual-phase FDG PET/CT. Some of the proposed cutoff values were as follows: lesion SUVmax at time 1, 7.20 (sensitivity, 89.2%; specificity, 85.7%); lesion SUVmax at time 2, 7.80 (sensitivity, 97.3%; specificity, 71.4%); lesion-to-CWM SUVmax at time 1, 2.05 (sensitivity, 78.4%; specificity, 92.9%); and lesion-to-CWM SUVmax at time 2, 2.36 (sensitivity, 81.1%; specificity, 85.7%). CONCLUSION. Dual-phase FDG PET/CT improves lesion detection and diagnostic accuracy in malignant brain tumors.

Hypothalamic hamartomas and inner ear diverticula with X-linked stapes gusher syndrome - new associations?

X-linked stapes gusher syndrome is a genetic form of deafness with distinct radiographic features on temporal bone CT. Hypothalamic hamartoma is a congenital glioneuronal anomaly of the hypothalamus. We report a potential association between these two rare anomalies that, to our knowledge, has not been reported. Two brothers presented with sensorineural hearing loss and almost identical inner ear and hypothalamic abnormalities, consistent with a diagnosis of X-linked stapes gusher syndrome and hypothalamic hamartoma. Genetic testing revealed identical mutations in the POU3F4 gene associated with X-linked stapes gusher syndrome. Furthermore, multiple vestibular diverticula were seen in both brothers, which have also not been reported with X-linked stapes gusher syndrome. This case suggests that POU3F4 mediated X-linked stapes gusher syndrome may also lead to multiple vestibular diverticula and hypothalamic hamartoma and, therefore, brain magnetic resonance imaging (MRI) could be considered in patients presenting with these inner ear findings.

The efficacy of fluoroscopy-guided epidural blood patch in the treatment of spontaneous and iatrogenic cerebrospinal fluid leakage.

OBJECTIVE: To evaluate patient outcomes following fluoroscopy-guided epidural blood patch (FGEBP), factors affecting the outcome, and to identify the rate of fluoroscopy-guided lumbar punctures (FGLP) requiring FGEBP. METHODS: All FGLPs and FGEBPs between January 2014 and May 2017 were retrospectively evaluated. Information regarding patient characteristics, details of previous dural puncture (DP), details of the FGEBP, and FGEBP outcome were recorded. The outcome was classified into three categories as "complete response", "partial response", and "no response". Patients with "complete response" were compared to the combined group of "no response" and "partial response", classified as "incomplete response". Two-sample/Fisher's exact (continued/categorical variables) tests were used (p < 0.05). RESULTS: Sity-seven FGEBPs were performed in 63 patients (female/male, 36/27; mean age/BMI 38/28.2). Fifty-nine were referred following DP; 31 were performed by radiologists. The rate of FGLPs requiring FGEBP was 1.78% within 3.5 years. The mean DP-FGEBP interval was 4.8 days. "Complete response" was achieved in 56 (84.8%), "no response" was found following 4 (6%) procedures. Average applied blood volume was 16 cc (5-30 cc). No difference was found between "complete response" and "incomplete response" groups regarding age, sex, BMI, DP performer, DP level, DP fluoroscopy time, DP needle caliber/type, FGEBP level, FGEBP needle caliber/type, FGEBP fluoroscopy time, FGEBP performer, and applied blood volume (p > 0.05). Despite approaching significance, no statistically significant difference was found regarding the presence of previous DP (p = 0.06). CONCLUSIONS: The efficacy of FGEBP is high in a group of patients referred to radiology for treatment of CSF leakage with complete response in 84.8% of patients. KEY POINTS: • Fluoroscopy-guided epidural blood patch completely resolved symptoms in 85% of post-dural puncture headaches. • The success approaches 95% when including the patients with partial resolution of symptoms. • Epidural blood patch rate is found 1.8% following 1703 fluoroscopy-guided lumbar punctures.

Duplex ultrasonography findings are not related to menstrual cycle phases in women with early symptoms of lower extremity chronic venous disease.

PURPOSE: To investigate if duplex ultrasonography findings change according to the menstrual cycle phases in women with early symptoms of lower extremity chronic venous disease. METHODS: Thirty women (60 extremities) aged 18-50 years with regular menstrual cycles who presented with complaints of telangiectasia and/or trunk varices with accompanying leg pain were evaluated prospectively by duplex ultrasonography at three different times of a single menstrual cycle. Previous DVT or menstrual irregularities were exclusion criteria. All exams were performed by the same radiologist, under the same conditions. Reflux was provoked in the deep veins, great saphenous vein (GSV), and small saphenous vein (SSV) using the Valsalva maneuver. Reflux times in each vein and average diameters of the GSV and SSV were recorded. RESULTS: Reflux times showed no significant differences in any of the vein segments and the diameters of GSV and SSV were similar in the different menstrual phases (p > 0.05). Reflux was not predominant at any specific phase, and its presence was independent of menstrual phase. CONCLUSIONS: Reflux was not specific to a particular phase of menstrual cycle in women with early symptoms of chronic venous disease.

Occult Amyloid-ß-Related Angiitis: Neuroimaging Findings at 1.5T, 3T, and 7T MRI.

Cerebral amyloid angiopathy (CAA) is a progressive neurodegenerative small vessel disease that is associated with intracranial hemorrhage and cognitive impairment in the elderly. The clinical and radiographic presentations have many overlapping features with vascular cognitive impairment, hemorrhagic stroke, and Alzheimer disease (AD). Amyloid-ß-related angiitis (ABRA) is a form of primary CNS vasculitis linked to CAA, with the development of spontaneous autoimmune inflammation against amyloid in the vessel wall with resultant vasculitis. The diagnosis of ABRA and CAA is important. ABRA is often fatal if untreated and requires prompt immunosuppression. Important medical therapies such as anticoagulation and antiamyloid agents for AD are contraindicated in CAA. Here, we present a biopsy-proved case of ABRA with underlying occult CAA. Initial 1.5T and 3T MR imaging did not suggest CAA per the Boston Criteria 2.0. ABRA was not included in the differential diagnosis due to the lack of any CAA-related findings on conventional MR imaging. However, a follow-up 7T MR imaging revealed extensive cortical/subcortical cerebral microbleeds, cortical superficial siderosis, and intragyral hemorrhage in extensive detail throughout the supratentorial brain regions, which radiologically supported the diagnosis of ABRA in the setting of CAA. This case suggests an increased utility of high-field MR imaging to detect occult hemorrhagic neuroimaging findings with the potential to both diagnose more patients with CAA and diagnose them earlier.

Prevalence of Rathke's Cleft and Other Incidental Pituitary Gland Findings on Contrast-Enhanced 3D Fat-Saturated T1-MPRAGE at 7 Tesla MRI.

BACKGROUND AND PURPOSE: A cleft-like non-enhancing hypointensity was observed repeatedly in the pituitary gland at the adenohypophysis/neurohypophysis border on contrast-enhanced 3D-Fat-Saturated T1-MPRAGE (C+3D-FS-T1 MPRAGE) using clinical 7T MRI. Our primary goal is to assess the prevalence of this finding. The secondary goals are to evaluate the frequency of other incidental pituitary lesions, MRI artifacts, and their effect on pituitary imaging on the C+3D-FS-T1 MPRAGE at 7T. MATERIALS AND METHODS: 100 patients who underwent 7T neuroimaging between 10/27/2021 and 8/10/23 were included. Each case was evaluated for cleft-like pituitary hypointensity, pituitary masses, and artifacts on C+3D-FS-T1 MPRAGE. Follow-up exams were evaluated if present. The average prevalence for each finding was calculated, as were descriptive statistics for age and sex. RESULTS: A cleft-like hypointensity was present in 66% of 7T MRIs. There were no significant differences between the "cleft-like present" and "cleft-like absent" groups regarding sex (P = .39) and age (P = .32). The cleft-like hypointensity was demonstrated in follow-up MRIs in 3/3 patients with 7T, 1/12 with 3T, and 1/5 with 1.5T. A mass was found in 22%, while 75% had no mass, and 3% were indeterminate. A mass was found in 18 (27%) of the "cleft-like present" and 4 (13%) of the "cleft-like absent" groups. The most common mass types were Rathke cleft cyst (RCC) in 7 (31.8%) patients, "RCC vs. entrapped CSF" in 6 (27.3%), and microadenoma in 6 (22.2%) in the "cleft-like present" group. There were no significant differences in the mass types between the "cleft-like present" and "cleft-like absent" groups (P = .23). Susceptibility and/or motion artifacts were frequent in general using C+3D-FS-T1 MPRAGE (54%). Artifact-free scans were significantly more frequent in the "cleft-like present" group (P =.03). CONCLUSIONS: A cleft-like non-enhancing hypointensity was frequently seen on the C+3D-FS-T1 MPRAGE at 7T MRI, which most likely represents a normal embryological Rathke's cleft remnant and cannot be seen in lower field strength MRIs. Susceptibility and motion artifacts are common in the sella. They may affect image quality, and the artifacts at 7T may lead to an underestimation of the prevalence of Rathke cleft and other incidental findings. ABBREVIATIONS: C+3D-FS-T 1MPRAGE = Contrast-Enhanced 3D-Fat-Saturated T1-Magnetization Prepared Rapid Gradient Echo Imaging; RCC = Rathke's Cleft Cyst.

The active papillary muscle sign in 18F-FDG PET/CT cardiac sarcoidosis exams and its relationship with myocardial suppression.

OBJECTIVE: Papillary muscle (PM) activity may demonstrate true active cardiac sarcoidosis (CS) or mimic CS in 18FDG-PET/CT if adequate myocardial suppression (MS) is not achieved. We aim to examine whether PM uptake can be used as a marker of failed MS and measure the rate of PM activity presence in active CS with different dietary preparations. MATERIALS AND METHODS: We retrospectively reviewed PET/CTs obtained with three different dietary preparations. Diet-A: 24-h ketogenic diet with overnight fasting (n = 94); Diet-B: 18-h fasting (n = 44); and Diet-C: 72-h daytime ketogenic diet with 3-day overnight fasting (n = 98). Each case was evaluated regarding CS diagnosis (negative, positive, and indeterminant) and presence of PM activity. MaxSUV was measured from bloodpool, liver, and the most suppressed normal myocardium. Linear mixed-effects models were used to compare these factors between those with PM activity and those without. RESULTS: PM activity was markedly lower in the Diet-C group compared with others: Diet-C: 6 (6.1%), Diet-A: 36 (38.3%), and Diet-B: 26 (59.1%) (p < 0.001). MyocardiumMaxSUV was higher, and MyocardiummaxSUV/BloodpoolmaxSUV, MyocardiummaxSUV/LivermaxSUV ratios were significantly higher in the cases with PM activity (p < 0.001). Among cases that used Diet-C and had PM activity, 66.7% were positive and 16.7% were indeterminate. If Diet-A or Diet-B was used, those with PM activity had a higher proportion of indeterminate cases (Diet-A: 61.1%, Diet-B: 61.5%) than positive cases (Diet-A: 36.1%, Diet-B: 38.5%). CONCLUSION: Lack of PM activity can be a sign of appropriate MS. PM activity is less common with a specific dietary preparation (72-h daytime ketogenic diet with 3-day overnight fasting), and if it is present with this particular preparation, the likelihood that the case being true active CS might be higher than the other traditional dietary preparations.

Case report: Delayed posttraumatic cortical laminar necrosis secondary to spreading depolarization induced spreading ischemia from old subarachnoid hemorrhage.

Cortical laminar necrosis usually occurs secondary to infarcts or hypoxia, however other causes, including hypoglycemia, status epilepticus and immunosuppressive therapy have been reported. To our knowledge, CLN is not a phenomenon expected in the case of trauma. We report a unique case of delayed post-traumatic CLN which occurred 30 days after the initial trauma, without any proven cause apart from possible spreading depolarization induced spreading ischemia from adjacent subarachnoid hemorrhage with distinct radiologic features.

GammaTile® brachytherapy in the treatment of recurrent glioblastomas.

BACKGROUND: GammaTile® (GT) is a recent U.S. Food and Drug Administration (FDA) cleared brachytherapy platform. Here, we report clinical outcomes for recurrent glioblastoma patients after GT treatment following maximal safe resection. METHODS: We prospectively followed twenty-two consecutive Isocitrate Dehydrogenase (IDH) wild-type glioblastoma patients (6 O6-Methylguanine-DNA methyltransferase methylated (MGMTm); sixteen MGMT unmethylated (MGMTu)) who underwent maximal safe resection of recurrent tumor followed by GT placement. RESULTS: The cohort consisted of 14 second and eight third recurrences. In terms of procedural safety, there was one 30-day re-admission (4.5%) for an incisional cerebrospinal fluid leak, which resolved with lumbar drainage. No other wound complications were observed. Six patients (27.2%) declined in Karnofsky Performance Score (KPS) after surgery due to worsening existing deficits. One patient suffered a new-onset seizure postsurgery (4.5%). There was one (4.5%) 30-day mortality from intracranial hemorrhage secondary to heparinization for an ischemic limb. The mean follow-up was 733 days (range 279-1775) from the time of initial diagnosis. Six-month local control (LC6) and twelve-month local control (LC12) were 86 and 81%, respectively. Median progression-free survival (PFS) was comparable for MGMTu and MGMTm patients (~8.0 months). Median overall survival (OS) was 20.0 months for the MGMTu patients and 37.4 months for MGMTm patients. These outcomes compared favorably to data in the published literature and an independent glioblastoma cohort of comparable patients without GT treatment. CONCLUSIONS: This clinical experience supports GT brachytherapy as a treatment option in a multi-modality treatment strategy for recurrent glioblastomas.