Cerebral oxygen extraction fraction: Comparison of dual-gas challenge calibrated BOLD with CBF and challenge-free gradient echo QSM+qBOLD.

PURPOSE: To compare cortical gray matter oxygen extraction fraction (OEF) estimated from 2 MRI methods: (1) the quantitative susceptibility mapping (QSM) plus quantitative blood oxygen level dependent imaging (qBOLD) (QSM+qBOLD or QQ), and (2) the dual-gas calibrated-BOLD (DGCB) in healthy subjects; and to investigate the validity of iso-cerebral metabolic rate of oxygen consumption assumption during hypercapnia using QQ. METHODS: In 10 healthy subjects, 3 tesla MRI including a multi-echo gradient echo sequence at baseline and hypercapnia for QQ, as well as an EPI dual-echo pseudo-continuous arterial spin labeling for DGCB, were performed under a hypercapnic and a hyperoxic condition. OEFs from QQ and DGCB were compared using region of interest analysis and paired t test. For QQ, cerebral metabolic rate of oxygen consumption = cerebral blood flow*OEF*arterial oxygen content was generated for both baseline and hypercapnia, which were compared. RESULTS: Average OEF in cortical gray matter across 10 subjects from QQ versus DGCB was 35.5 ± 6.7% versus 38.0 ± 9.1% (P = .49) at baseline and 20.7 ± 4.4% versus 28.4 ± 7.6% (P = .02) in hypercapnia: OEF in cortical gray matter was significantly reduced as measured in QQ (P < .01) and in DGCB (P < .01). Cerebral metabolic rate of oxygen consumption (in µmol O2 /min/100 g) was 168.2 ± 54.1 at baseline from DGCB and was 153.1 ± 33.8 at baseline and 126.4 ± 34.2 (P < .01) in hypercapnia from QQ. CONCLUSION: The differences in OEF obtained from QQ and DGCB are small and nonsignificant at baseline but are statistically significant during hypercapnia. In addition, QQ shows a cerebral metabolic rate of oxygen consumption decrease (17.4%) during hypercapnia.

A model-based framework for correcting B1+ inhomogeneity effects in magnetization transfer saturation and inhomogeneous magnetization transfer saturation maps.

PURPOSE: In this work, we propose that Δ B1+ -induced errors in magnetization transfer (MT) saturation (MTsat ) maps can be corrected with use of an R1 and B1+ map and through numerical simulations of the sequence. THEORY AND METHODS: One healthy subject was scanned at 3.0T using a partial quantitative MT protocol to estimate the relationship between observed R1 (R1,obs ) and apparent bound pool size ( M0,appB ) in the brain. MTsat values were simulated for a range of B1+ , R1,obs , and M0,appB . An equation was fit to the simulated MTsat , then a linear relationship between R1,obs and M0,appB was generated. These results were used to generate correction factor maps for the MTsat acquired from single-point data. The proposed correction was compared to an empirical correction factor with different MT-preparation schemes. RESULTS: M0,appB was highly correlated with R1,obs (r > 0.96), permitting the use of R1,obs to estimate M0,appB for B1+ correction. All B1+ corrected MTsat maps displayed a decreased correlation with B1+ compared to uncorrected MTsat and MTsat corrected with an empirical factor in the corpus callosum. There was good agreement between the proposed approach and the empirical correction with radiofrequency saturation at 2 kHz, with larger deviations seen when using saturation pulses further off-resonance and in inhomogeneous (ih) MTsat maps. CONCLUSION: The proposed correction decreases the dependence of MTsat on B1+ inhomogeneities. Furthermore, this flexible framework permits the use of different saturation protocols, making it useful for correcting B1+ inhomogeneities in ihMT.

The utility of cranial ultrasound as a screening tool for neonatal ECMO.

Background Neurologic complications including hemorrhage, ischemia, and infarction are often identified in neonates undergoing extracorporeal membrane oxygenation (ECMO) and may contribute to the high morbidity observed in ECMO survivors. Screening for intracranial complications is reliant on bedside transcranial ultrasound (CUS) prior to and during ECMO therapy, and advanced imaging [i.e. computed tomography (CT)/magnetic resonance imaging (MRI)] is recommended after completion of ECMO support. The goal of this study is to describe the correlation of intracranial complications identified on CUS during ECMO and MRI after completion of ECMO. Methods Fifty-five neonates underwent ECMO support at the Children's Hospital of Georgia at Augusta University from January 1, 2012 to December 31, 2017. Forty-four (80%) had a brain MRI performed prior to transfer or discharge. Ultrasound studies were reviewed by a single blinded pediatric radiologist and MRIs were reviewed by a single blinded neuro-radiologist. Results Of the 44 neonates with post-ECMO MRI, CUS during ECMO identified intracranial lesions in nine neonates, which were all confirmed on post-ECMO MRI. Sixteen subjects (46%) with unremarkable CUS during ECMO had identifiable lesions on post-ECMO MRI, yielding a sensitivity of 36% and a specificity of 100% for CUS in the detection of intracranial lesions. Despite the lack of correlation between CUS and MR, 84.6% of survivors exhibited normal development at 24 months of age. Conclusion While necessary for the identification of intracranial lesions during neonatal ECMO, CUS demonstrated low correlation with post-ECMO MRI in the identification of intracranial lesions, which supports Extracorporeal Life Support Organization (ELSO) recommendations.

Head and Neck Sarcomas: A Review of Clinical and Imaging Findings Based on the 2013 World Health Organization Classification.

OBJECTIVE: Head and neck sarcomas are a complex, heterogeneous group of tumors that present a diagnostic challenge to radiologists because they have many overlapping imaging features. The purpose of this article is to review the imaging and clinical features and highlight distinguishing features of head and neck sarcomas. CONCLUSION: An understanding of characteristic imaging and clinical features of head and neck sarcomas is important for the radiologist to narrow the differential diagnosis and help guide management.

Fertility Preservation in Pubertal and Pre-Pubertal Boys with Cancer.

Children diagnosed with cancer continue to have improved survival due to advances in effective treatment options. Increased attention is therefore now focused on quality of life issues once they are cured. Fertility preservation is of paramount concern since gonadotoxic treatments, especially radiation and chemotherapy, often impair future fertility. The importance of family counseling and having an informed discussion about the potential for treatment to impair fertility and the options available for fertility preservation is crucial. However, fertility preservation in prepubertal boys is challenging, but not impossible. Experimental methods are being investigated including cryopreservation of immature testicular tissue, xenografting, and in vitro germ cell maturation. Despite the success and relative ease of sperm banking, barriers exist and affect the number of patients offered treatment. Education and awareness of the possibilities can overcome these barriers. In this way we will continue to preserve young patients' future fertility and quality of life.

Penile Doppler ultrasound predicting cardiovascular disease in men with erectile dysfunction.

Cardiovascular disease is a major cause of morbidity and mortality in the USA. Traditional risk factors such as obesity, physical inactivity, and diet are used to screen for cardiovascular disease. However, these risk factors miss a significant population who are at risk for future cardiac events. Erectile dysfunction (ED) has many associated conditions in common with cardiovascular disease and has been shown to be an independent risk factor for cardiovascular. Measurements made on penile Doppler ultrasound (PDU), such as cavernosal artery peak systolic velocity (PSV), cavernosal artery intima-medial thickness, and the finding of cavernosal artery calcification, are indicators of generalized vascular disease. Thus, elements of PDU can identify men at higher risk for cardiovascular disease. This review outlines the proper technique for PDU and the literature supporting the use of PDU to predict cardiovascular disease in men with erectile dysfunction.

Penile sonoelastography for the localization of a non-palpable, non-sonographically visualized lesion in a patient with penile curvature from Peyronie's disease.

INTRODUCTION: Sonoelastography is an emerging ultrasound-based technique that allows characterization of tissue stiffness. AIM: The aim of this report is to present a case of significant penile curvature with a non-palpable, non-sonographically visualized plaque that was demonstrable with sonoelastography. METHODS: A 60-year-old male presented with significant left penile curvature during erections. The penis was evaluated with physical exam followed by B-mode and color Doppler ultrasound. No evidence of plaque was identified with these modalities. Shear wave sonoelastography was pursued to further characterize the patient's Peyronie's disease. RESULTS: An area of increased tissue stiffness that correlated with the site of maximum curvature was identified with shear wave sonoelastography and used to target intralesional injection therapy. CONCLUSION: Sonoelastography provides an additional way to characterize, localize, and deliver therapy to a lesion in patients with Peyronie's disease and is particularly useful when palpation and B-mode ultrasonography have failed to demonstrate a plaque.

Spectral Doppler sonography: a noninvasive method for predicting dyspermia.

OBJECTIVES: Sonography is a noninvasive, office-based diagnostic tool often used for evaluation of subfertile men. Previous studies have suggested that a resistive index (RI) greater than 0.6 is associated with impaired spermatogenesis. We sought to validate this threshold in a urologic patient population presenting for infertility evaluation. METHODS: We retrospectively reviewed 99 consecutive patients seen for nonobstructive male infertility at our institution. Patient demographics, semen analysis parameters, hormone profiles, lipid profiles, and penile and scrotal sonographic measurements were recorded. The RI was calculated from measurements of the peak systolic velocity and end-diastolic velocity. Ninety-one patients fit the inclusion criteria and were subsequently divided into 2 groups based on RI: group 1 with RI values of 0.6 or less (n = 49) and group 2 with RI values greater than 0.6 (n = 42). RESULTS: Variables that were significantly different between the groups included age, total sperm count, percent motile sperm, total motile sperm, follicle-stimulating hormone, high-density lipoprotein, and testis volume. On the other hand, body mass index, forward progression, World Health Organization score, total testosterone, free testosterone, estradiol, total cholesterol, low-density lipoprotein, and triglycerides were not significantly different between the groups. A receiver operating characteristic curve revealed an area under the curve of 0.64 (confidence interval, 0.52-0.75; P = .025). At the threshold of greater than 0.6, the RI had specificity of 63.27% and a 1.56 likelihood ratio to predict total motile sperm less than 20 × 10(6) at spermatogenesis. CONCLUSIONS: An intratesticular RI greater than 0.6 is associated with impaired spermatogenesis. This finding supports the use of testicular spectral Doppler sonography as a noninvasive tool for evaluation of testicular function.

Noninvasive Calculation of Cerebrospinal Fluid Production Using Phase-Contrast Magnetic Resonance Imaging: First Implementation in Augusta, Georgia.

This retrospective review examines the utility of phase-contrast magnetic resonance imaging (PC-MRI) to calculate flow through the aqueduct between the third and fourth ventricles to estimate cerebrospinal fluid (CSF) production. Imaging software quantified the CSF flow rate across the aqueduct of four females and two males at a single center, and the mean of these results was compared to the established mean CSF production calculated by invasive techniques. There was no significant difference between the means, contributing to the body of literature suggesting the utility of PC-MRI in estimating CSF production rates.

Office ultrasound for the urologist.

Imaging of the genitourinary tract is essential in the workup of the majority of the conditions seen daily by urologists. The use of ultrasound in the office provides a safe, low cost, and efficient way for the clinician to evaluate the patient in real time. Ultrasound can allow for bedside diagnosis in many conditions and assist in treatment planning. This chapter covers the major applications of office ultrasound for the urologist as well as discusses future applications of ultrasound for the office setting.

Endoscope-assisted far lateral craniotomy for resection of posterior fossa neurocysticercosis: illustrative case.

BACKGROUND: Neurocysticercosis is a parasitic infection that commonly affects the ventricles, subarachnoid spaces, and spinal cord of the central nervous system. The authors report an unusual manifestation of purely posterior fossa neurocysticercosis treated with endoscope-assisted open craniotomy for resection. OBSERVATIONS: A 67-year-old male presented with 2 months of progressive dizziness, gait ataxia, headaches, decreased hearing, and memory impairment. Imaging revealed an extra-axial cystic lesion occupying the foramen magnum and left cerebellopontine angle with significant mass effect and evidence of early hydrocephalus. Gross-total resection was accomplished via a left far lateral craniotomy with open endoscopic assistance, and pathological findings were consistent with neurocysticercosis. Postoperatively, he was noted to have a sixth nerve palsy, and adjuvant therapy included albendazole. By 9 months postoperatively, he exhibited complete resolution of an immediate postoperative sixth nerve palsy in addition to all preoperative symptoms. His hydrocephalus resolved and did not require permanent cerebrospinal fluid (CSF) diversion. LESSONS: When combined with traditional skull base approaches, open endoscopic techniques allow for enhanced visualization and resection of complex lesions otherwise inaccessible under the microscope alone. Recognition and obliteration of central nervous system neurocysticercosis can facilitate excellent neurological recovery without the need for CSF diversion.

Anatomy of the Ventricles, Subarachnoid Spaces, and Meninges.

The ventricular system, subarachnoid spaces, and meninges are structures that lend structure, support, and protection to the brain and spinal cord. This article provides a detailed look at the anatomy of the intracranial portions of these structures with a particular focus on neuroimaging methods.

Focused ultrasound resolves persistent radiosurgery related change in a patient with tremor.

We report on a patient who underwent magnetic resonance guided focused ultrasound (MRgFUS) thalamotomy to treat tremor 3 years after a stereotactic radiosurgery (SRS) thalamotomy. The SRS produced only limited and transient improvements and was associated with a persistent hyperintensity on T2-FLAIR MR images. The MRgFUS thalamotomy was successful, with tremor improvement at 3 months, no adverse effects, and radiological appearance of the MRgFUS lesion similar to other patients undergoing this therapy. We also observed that the SRS-related T2-FLAIR hyperintensity had increased signal intensity 1 day post-MRgFUS, but appeared completely resolved 3 months post-MRgFUS. In conclusion, the case demonstrates that MRgFUS thalamotomy may effectively control tremor in patients with a history of SRS thalamotomy. We also speculate on the potential mechanisms of the apparent resolution of radiation-related change, and discuss possible applications of MRgFUS to reduce persistent SRS-related inflammation.

Suprasellar Ganglioglioma: Expanding the Differential Diagnosis.

This case study describes a young man with symptoms suggestive of the presence of a space-occupying lesion within the cranial cavity. Imaging studies confirmed a lesion in the suprasellar region and surgical intervention to remove the tumor yielded an unexpected diagnosis. Neuroimaging characteristics and histopathology including immunohistochemistry are described. Gangliogliomas are uncommon CNS neoplasms and are most commonly found in the temporal and frontal lobes of young, male adults. They are rarely seen in the suprasellar region and only a handful of cases have been reported to date. The differential diagnoses associated with these suprasellar region lesions can be dependent on the age of the patient and neuroimaging characteristics. The present report highlights the importance of histopathological examination and the need to consider a wide range of diagnostic entities in the differential diagnosis of lesions in this topographic distribution, including rarely encountered tumors such as gangliogliomas.

The effects of chelating agents on radical generation in alkaline peroxide systems, and the relevance to substrate damage.

A spin-trapping EPR technique has been employed to explore the generation of hydroxyl radicals from reactions between a series of first row transition metal ions and aqueous hydrogen peroxide at pH 10, and with a range of chelating agents (EDTA, DTPMP and the readily biodegradable ligands S,S-EDDS and IDS). In the absence of these chelating agents only Cu(II) generates a significant level of hydroxyl radicals; in their presence with Cu(II) EDTA and IDS give similar behaviour whereas EDDS and DTPMP inhibit hydroxyl radical generation. For Fe(II), EDTA, DTPMP and IDS significantly enhance ( radical)OH production under these conditions whereas EDDS does not. Results from model cellulose damage experiments broadly confirm the findings for copper, though experiments with Fe(II) lead to somewhat contrasting results. Our findings are discussed in terms of binding constants and implications for alkaline peroxygen bleaching systems.

Bulbocavernosus muscle area as a novel marker for hypogonadism.

OBJECTIVE: Late-onset hypogonadism, or androgen deficiency in the aging male, is a significant cause of morbidity in older men. Many men in the low normal or equivocal range for low testosterone level exhibit signs and symptoms of hypogonadism. Serum testosterone is an imperfect maker for hypogonadism as symptoms vary greatly within the low to low normal range in addition to variations among testosterone assays. Perineal ultrasound can be effectively used to examine the bulbocavernosus muscle (BCM), an androgenized tissue that may be impacted by androgen receptor activity. METHODS: This study was a retrospective analysis of men who underwent perineal ultrasound for hypogonadism. The ultrasound data were used to calculate the area of the BCM and correlate it with indices of hypogonadismin symptomatic men including free and total testosterone and dual-energy X-ray absorptiometry (DEXA). RESULTS: The results demonstrate that there is a significant correlation between total and free testosterone and BCM area in hypogonadal patients. Comparison between BCM area and total testosterone showed R2  = 0.061 and p = 0.0187 and comparison between BCM area and free testosterone showed R2  = 0.0957 and p = 0.0034. In addition, low BCM was also correlated with DEXA results showing osteoporosis and osteopenia (R2  = 0.2239, p = 0.0027). CONCLUSION: There has been recent controversy over the safety of testosterone replacement therapy. This might be particularly important in men with hypogonadal symptoms but a low normal testosterone level. Our study investigated the use of perineal ultrasound to measure BCM as a surrogate marker for poor androgenized men presenting with hypogonadism.

Stroke in a Child with Hemoglobin SC Disease: A Case Report Describing use of Hydroxyurea after Transfusion Therapy.

Children with hemoglobin SC (HbSC) disease suffer a significant incidence of silent cerebral infarcts but stroke is rare. A 2-year-old African American boy with HbSC disease presented with focal neurologic deficits associated with magnetic resonance imaging evidence of cerebral infarction with vascular abnormalities. After the acute episode he was treated with monthly transfusions and subsequently transitioned to hydroxyurea therapy. The benefits of hydroxyurea as a fetal hemoglobin inducer in HbSC disease, to ameliorate clinical symptoms are supported by retrospective studies. This case highlights the rare occurrence of stroke in a child with HbSC disease and the use of hydroxyurea therapy.

Imaging and angiography in male factor infertility.

Ultrasound imaging and angiography play a crucial role in the diagnosis and treatment of men with subfertility. The most commonly used imaging modality is ultrasound (US), which can be used for diagnostic purposes or to aid in treatment. Scrotal US can be used to document varicoceles in subfertile men in the context of difficult examination or for confirmation before treatment. Spectral Doppler, sonoelastography, and power Doppler have aided in the evaluation and treatment of azoospermia and oligospermia. They have proven useful in the detection of spermatogenesis and sperm retrieval. In the population with congenital Wolffian duct abnormalities, renal US can evaluate renal anomalies. In subfertile men with low ejaculate volume and oligospermia or azoospermia transrectal US can be used to evaluate and assist in treatment of ejaculatory duct obstruction. Non-US-based modalities are also commonly used in evaluating and treating men with subfertility. Magnetic resonance imaging (MRI) can be used for evaluation of pituitary adenomas in hypogonadism. More invasive imaging modalities used during treatment of subfertile men include vasography for vasal obstruction, venography and angioembolization for varicocele, and US-guided needle placement for testis-sparing surgery. Male subfertility is a complex problem and the use of imaging techniques is often essential in providing accurate diagnosis and appropriate treatment.

ALK positive Anaplastic Large Cell Lymphoma of the Thoracic Spine.

Primary bone lymphoma (PBL) is an uncommon extra nodal disease that represents about 1-3% of lymphoma cases. Imaging findings are variable and non-specific. Computed tomography may demonstrate lytic lesions with sequestra and periosteal reaction. On magnetic resonance imaging, lesions are T1WI hypointense and T2WI hyperintense, related to peritumoral edema or bone marrow replacement. Rarely lesions may have associated fibrosis and show a more hypointense signal pattern on T2WI. After administration of contrast, PBL tends to enhance avidly. We present a case of a 24 years old African American female patient with history of back pain. Initial imaging examinations showed lesions involving the T12 and T11 vertebral bodies with initial negative biopsy results. One month later, the patient returned with worsening back pain, and the follow up studies depicted collapse of the T12 vertebral body. A diagnosis of anaplastic large cell lymphoma in T12 was made. A brief review of the literature, imaging and pathological findings, and treatment options are also discussed.