Comparison of Four Dual-Energy CT Scanner Technologies for Determining Renal Stone Composition: A Phantom Approach.

Background Studies have investigated the value of various dual-energy CT (DECT) technologies for determining renal stone composition. However, sparse multivendor comparison data exist. Purpose To compare the performance of four DECT technologies in determining renal stone composition at standard- and low-dose acquisitions. Materials and Methods This was an in vitro phantom study. Seventy-one urinary stones (size: 2.7-14.1 mm) of known chemical composition (51 calcium, four struvite, four cystine, and 12 urate) were placed in a custom-made cylindrical phantom. Consecutive scans with manufacturer-recommended protocols and dose-optimized institutional protocols (up to 80% reduction in volumetric CT dose index) were obtained with rapid kilovolt peak switching DECT (rsDECT) (n = 2), dual-source DECT (n = 2), twin-beam DECT (tbDECT) (n = 1), and dual-layer detector-based CT (dlDECT) (n = 1) scanners. The image data sets were analyzed using effective atomic number and dual-energy ratio indexes of maximally available and comparable spectra. The performance of each combination of scanner technology, method, and acquisition was assessed. Logistic regression models were used to calculate the area under the receiver operating characteristic curve (AUC). Results After image analysis, all scanners except tbDECT had an AUC greater than 0.95 in at least one acquisition in distinguishing urate from other stones. All DECT techniques were able to help differentiate calcium oxalate monohydrate stones with moderate accuracy (AUC: 0.70-0.83), and brushite was differentiated from urate with AUC greater than 0.99. There was no correlation between performance and acquisition with dose-optimized and/or vendor-recommended settings. Conclusion All four dual-energy CT (DECT) technologies enabled accurate determination of stone composition at standard- and low-dose acquisitions; however, performance varied based on the scanner parameters, DECT technique, and stone type. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Ringl and Apfaltrer in this issue.

Performance evaluation of a micro-CT system for laboratory animal imaging with iterative reconstruction capabilities.

BACKGROUND: In recent years, there has been a rapid proliferation in micro-computed tomography (micro-CT) systems becoming more available for routine preclinical research, with applications in many areas, including bone, lung, cancer, and cardiac imaging. Micro-CT provides the means to non-invasively acquire detailed anatomical information, but high-resolution imaging comes at the cost of longer scan times and higher doses, which is not desirable given the potential risks related to x-ray radiation. To achieve dose reduction and higher throughputs without compromising image quality, fewer projections can be acquired. This is where iterative reconstruction methods can have the potential to reduce noise since these algorithms can better handle sparse projection data, compared to filtered backprojection PURPOSE: We evaluate the performance characteristics of a compact benchtop micro-CT scanner that provides iterative reconstruction capabilities with GPU-based acceleration. We thereby investigate the potential benefit of iterative reconstruction for dose reduction. METHODS: Based on a series of phantom experiments, the benchtop micro-CT system was characterized in terms of image uniformity, noise, low contrast detectability, linearity, and spatial resolution. Whole-body images of a plasticized ex vivo mouse phantom were also acquired. Different acquisition protocols (general-purpose versus high-resolution, including low dose scans) and different reconstruction strategies (analytic versus iterative algorithms: FDK, ISRA, ISRA-TV) were compared. RESULTS: Signal uniformity was maintained across the radial and axial field-of-view (no cupping effect) with an average difference in Hounsfield units (HU) between peripheral and central regions below 50. For low contrast detectability, regions with at least ∆HU of 40 to surrounding material could be discriminated (for rods of 2.5 mm diameter). A high linear correlation (R2  = 0.997) was found between measured CT values and iodine concentrations (0-40 mg/ml). Modulation transfer function (MTF) calculations on a wire phantom evaluated a resolution of 10.2 lp/mm at 10% MTF that was consistent with the 8.3% MTF measured on the 50 µm bars (10 lp/mm) of a bar-pattern phantom. Noteworthy changes in signal-to-noise and contrast-to-noise values were found for different acquisition and reconstruction protocols. Our results further showed the potential of iterative reconstruction to deliver images with less noise and artefacts. CONCLUSIONS: In summary, the micro-CT system that was evaluated in the present work was shown to provide a good combination of performance characteristics between image uniformity, low contrast detectability, and resolution in short scan times. With the iterative reconstruction capabilities of this micro-CT system in mind (ISRA and ISRA-TV), the adoption of such algorithms by GPU-based acceleration enables the integration of noise reduction methods which here demonstrated potential for high-quality imaging at reduced doses.

A spectrum of findings on computed tomography in paediatric abdominal and pelvic tumours in a Ghanaian teaching hospital

Objectives: To review the Computed Tomography( CT )features of pediatric oncological patients with abdominal and pelvic tumours and correlate these findings with their histopathological diagnosis Design: This was a retrospective cross-sectional facility-based study. Setting: This study was conducted in the Pediatric Oncology Unit and Radiology Department of the Korle Bu Teaching Hospital Participants: Fifty-six pediatric oncology patients with contrast-enhanced abdominal and pelvic CT scans. Data Collection: The abdominal and pelvic CT scans findings, patient biodata, and histopathology reports of oncology patients over four years were reviewed Statistical analysis: Simple descriptive statistics using frequency distribution, percentages, means, and standard deviation were used to describe the various variables and presented tables. Results: The four commonest tumours were nephroblastoma, neuroblastoma, lymphoma, and hepatoblastoma. The mean age at diagnosis was 4.8 years, with a slightly higher male predominance. The majority of the tumours were extremely large at presentation. Overall, the CT ­ histopathology concordance was 79.2%. Conclusion: Abdominal and pelvic CT scans play an important role in the diagnostic workup of pediatric malignancies by ensuring early and accurate diagnosis of these tumour

Disseminated Nocardia infection with a lesion occupying the intracranial space complicated with coma: a case report.

BACKGROUND: Disseminated Nocardia infection is a disease that is easily overlooked in patients with lesions occupying the intracranial space complicated with coma. Early diagnosis and treatment are crucial. CASE PRESENTATION: A 65-year-old man was admitted to the First Affiliated Hospital of Zhejiang University in October 2018 with weakness in the right limbs for 3 days and altered consciousness for 1 day. Five months earlier, he had been diagnosed with membranous kidney disease and had received cyclophosphamide and prednisone. At admission, the white blood cell count was 1.37 × 1010/L (with 86.4% neutrophils), and C-reactive protein was 115.60 mg/L. Imaging examinations revealed a lesion occupying the intracranial space, lung infection, and multiple abscesses in the rhomboid muscle. The abscesses were drained. Pus culture confirmed Nocardia cyriacigeorgica infection. With antibiotics and vacuum-sealed drainage of the back wound, the patient improved and was discharged from the hospital. CONCLUSIONS: This case report shows that infection should be considered during the differential diagnosis of lesions in the intracranial space, especially in patients receiving immunosuppressive treatment. In patients with disseminated N. cyriacigeorgica infection, combination antibiotic therapy and surgical drainage of localised abscesses can be effective.

Paratesticular Mesenchymal Malignancies: A Single-Center Case Series, Clinical Management, and Review of Literature.

Background: Primary soft tissue sarcomas arising from the male urinary and genital tract are rare tumors, only accounting for 1% to 2% of all malignancies of the genitourinary tract. Clinical management of advanced disease is lacking in standardized recommendations due to the rarity of the disease. To date, complete and extensive surgery represents the only curative and standardized approach for localized disease, while the impact of retroperitoneal lymphadenectomy and adjuvant treatments on clinical outcomes are still unclear. Similarly, a standardized systemic treatment for advanced metastatic disease is still missing. Cases Presentation: Four out of 274 patients have been identified in our sarcoma population. The mean age was 54 years (range = 45-73). The histotypes showed liposarcoma in 2 cases and leiomyosarcoma in the remaining 2 cases. In all 4 cases, the disease was localized at presentation, patients underwent complete surgery, and no adjuvant treatments were done. Three cases presented a recurrence of disease at a mean follow-up of 86 months (range = 60-106 months), more than 7 years. Two cases were treated with a second surgery and chemotherapy and 1 case only with chemotherapy. Discussion and Conclusions: Sharing data about clinical management of paratesticular mesenchymal tumors is a key issue due to the rarity of this tumor's subtype. In this article, we report the clinical history of 4 patients affected by paratesticular mesenchymal tumor. In particular, main issues of interest are the decision of postoperative treatment and systemic treatment at time of disease recurrence.

Technical assessment of a mobile CT scanner for image-guided brachytherapy.

PURPOSE: The imaging performance and dose of a mobile CT scanner (Brainlab Airo®, Munich, Germany) is evaluated, with particular consideration to assessment of technique protocols for image-guided brachytherapy. METHOD: Dose measurements were performed using a 100-mm-length pencil chamber at the center and periphery of 16- and 32-cm-diameter CTDI phantoms. Hounsfield unit (HU) accuracy and linearity were assessed using materials of specified electron density (Gammex RMI, Madison, WI), and image uniformity, noise, and noise-power spectrum (NPS) were evaluated in a 20-cm-diameter water phantom as well as an American College of Radiology (ACR) CT accreditation phantom (Model 464, Sun Nuclear, Melbourne, FL). Spatial resolution (modulation transfer function, MTF) was assessed with an edge-spread phantom and visually assessed with respect to line-pair patterns in the ACR phantom and in structures of interest in anthropomorphic phantoms. Images were also obtained on a diagnostic CT scanner (Big Bore CT simulator, Philips, Amsterdam, Netherlands) for qualitative and quantitative comparison. The manufacturer's metal artifact reduction (MAR) algorithm was assessed in an anthropomorphic body phantom containing surgical instrumentation. Performance in application to brachytherapy was assessed with a set of anthropomorphic brachytherapy phantoms - for example, a vaginal cylinder and interstitial ring and tandem. RESULT: Nominal dose for helical and axial modes, respectively, was 56.4 and 78.9 mGy for the head protocol and 17.8 and 24.9 mGy for the body protocol. A high degree of HU accuracy and linearity was observed for both axial and helical scan modes. Image nonuniformity (e.g., cupping artifact) in the transverse (x,y) plane was less than 5 HU, but stitching artifacts (~5 HU) in the longitudinal (z) direction were observed in axial scan mode. Helical and axial modes demonstrated comparable spatial resolution of ~5 lp/cm, with the MTF reduced to 10% at ~0.38 mm-1 . Contrast-to-noise ratio was suitable to soft-tissue visualization (e.g., fat and muscle), but windmill artifacts were observed in helical mode in relation to high-frequency bone and metal. The MAR algorithm provided modest improvement to image quality. Overall, image quality appeared suitable to relevant clinical tasks in intracavitary and interstitial (e.g., gynecological) brachytherapy, including visualization of soft-tissue structures in proximity to the applicators. CONCLUSION: The technical assessment highlighted key characteristics of dose and imaging performance pertinent to incorporation of the mobile CT scanner in clinical procedures, helping to inform clinical deployment and technique protocol selection in brachytherapy. For this and other possible applications, the work helps to identify protocols that could reduce radiation dose and/or improve image quality. The work also identified areas for future improvement, including reduction of stitching, windmill, and metal artifacts.

Lung cancer screening in patients with Libby amphibole disease: High yield despite predominantly environmental and household exposure.

BACKGROUND: Lung cancer screening with low-dose computed tomography (CT) scanning (LDCT) is accepted as a screening tool, but its application to populations exposed to recognized occupational or environmental carcinogens is limited. We apply LDCT to a population with a predominantly nonoccupational exposure to a recognized human lung carcinogen, Libby amphibole asbestos (LA). METHODS: Patients in an asbestos disease clinic in Libby, Montana who were aged 50 to 84 years, greater than or equal to 20 pack-year history of tobacco use (irrespective of quit date), and asbestos-related pleuropulmonary disease on high-resolution CT scan were offered free annual lung cancer screening over a 39-month period. RESULTS: Of 2897 clinic patients, 1149 (39.7%) met eligibility criteria, and 567 (49%) were screened with 1014 low-dose CT scans. Most screened patients had principally environmental (333 or 59%) or household exposure (145 or 25%) to LA. Seventeen primary lung cancers were identified, mostly in early stages: 10 at stage 1, two at stage 2, three at stages 3 to 4, and two at limited small-cell cancers. The screening yield was 1.9 at baseline scan and 1.5% on the first annual scan. CONCLUSIONS: Consistent with the guidelines of the National Comprehensive Cancer Network and American Association of Thoracic Surgery, LDCT for early lung cancer detection should be offered to people with significant exposure to occupational or environmental human lung carcinogens.

Targeting optimal time for hyperbaric oxygen therapy following carbon monoxide poisoning for prevention of delayed neuropsychiatric sequelae: A retrospective study.

OBJECTIVES: Delayed neuropsychiatric sequelae (DNS) are serious complications of carbon monoxide poisoning; neuropsychiatric disorders can occur within a few days of recovery from acute poisoning. Hyperbaric oxygen therapy (HBOT) has been the main treatment of carbon monoxide (CO) poisoning and was recommended as the treatment choice for CO poisoning by the American Undersea and Hyperbaric Medical Society and the Tenth European Consensus Conference on Hyperbaric Medicine of the European Underwater and Baromedical Society. However, the optimal timing for commencing HBOT in patients with CO poisoning remains unknown. We therefore conducted a retrospective study in an attempt to target the optimal time of HBOT for DNS prevention. METHODS: A retrospective review of patient files/medical records was conducted on all patients with CO poisoning admitted to the Emergency Department of Linkou Chang-Gung Memorial Hospital, Taiwan between January 1, 2009 and December 31, 2015. A total of 279 patients who received HBOT were eligible for further DNS detection. DNS was defined as the presence of one of the following neurological, cognitive, or psychological sequelae that were documented in the medical record during hospital stay or outpatient clinic follow-up for at least 6 months. A multivariable logistic regression analysis was employed to identify potential determinants of DNS after receiving HBOT for CO poisoning. A receiver operating characteristic (ROC) curve was used to analyse the influence of duration from CO exposure to HBOT on DNS development. RESULTS: A Glasgow coma score of <9 (odds ratio [OR], 3.20; 95% confidence interval [CI], 1.19-8.60) and a longer duration from CO exposure to HBOT (OR, 1.06; 95% CI, 1.03-1.09) were associated with a higher risk of DNS. By contrast, the presence of multiple victims from the same incident was associated with a lower risk of DNS. The ROC curve for the duration between CO exposure and HBOT in predicting DNS development demonstrated an area under the curve of 0.638 (95% CI, 0.575-0.698). The optimal cut-off point according to the Youden index was 22.5 h, with a sensitivity of 41.7% and a specificity of 85.9%. We also stratified the duration from CO exposure to HBOT into 5 intervals (< 6 h, 6-11 h, 12-23 h, 24-47 h and ≥ 48 h) and revealed a trend of increasing DNS risk with time. CONCLUSIONS: We identified several potential predictors of DNS in patients with CO poisoning who received HBOT. Multivariable logistic regressions further revealed that longer duration from CO exposure to HBOT, loss of consciousness, and the presence of multiple victims were independent predictors of DNS development. HBOT should be performed as early as possible and preferably within 22.5 h after CO poisoning.

Transarterial chemoembolization for unresectable hepatocellular carcinoma: A comparison of the efficacy and safety of 2 embolic agents.

The aim of this study was to compare the efficacy and safety of 2 different embolic agents, namely gelatin sponge particle (GSP) and Lipiodol, for transarterial chemoembolization (TACE) of unresectable hepatocellular carcinoma (HCC).We retrospectively reviewed 87 consecutive patients with unresectable HCC who underwent Lipiodol TACE with lobaplatin and 87 consecutive patients with unresectable HCC who underwent GSP TACE with lobaplatin between January 2013 and June 2017 in our institution as the initial treatment. Both groups were compared considering the clinical and laboratory outcomes and imaging findings before and after TACE. Tumor response and adverse events were also evaluated.There was significant difference in the rate of complete and overall response between the groups (P = .029 and .001, respectively), specifically when the tumor size was >5 cm (P = .001). The disease control rate was significantly better in the GSP group than in the Lipiodol group (94.3% vs. 86.4%, P = .011). The response differences in higher stages were significant between the 2 groups (P = .035 and .007, respectively). The grades of adverse events were also significantly different between the groups (P = .000).GSP-as an embolic agent in TACE for HCC-could significantly increase the rate of tumor response 1 month after treatment, especially in large tumors, without any significant increase in severe adverse events, when compared to Lipiodol.

Reversible ventriculoperitoneal shunt dysfunction and chronic constipation: case report.

Constipation can cause transient malfunction of the ventriculoperitoneal shunt (VPS). Patients with myelomeningocele or cerebral palsy are often diagnosed with hydrocephalus and constipation due to neurogenic bowel. These patients are more prone to VPS dysfunction, often requiring surgical revision. The authors report the case of a 6-year-old girl with a VPS that had been implanted due to hydrocephalus secondary to myelomeningocele. The patient was brought to the emergency department with intermittent headache, vomiting, constipation, and abdominal distension and pain. A CT scan revealed ventricular dilatation and radiography of the abdomen showed bowel loop distension. After a Fleet enema and digital maneuvers, her abdominal distension and symptoms improved. A CT scan obtained 24 hours later showed a reduction in ventricular size. The mechanism by which constipation can lead to VPS malfunction can be traced to indirect increases of intraabdominal pressure and direct obstruction of the catheter by distended intestinal loops. Treating constipation can restore the free circulation of the CSF and avoid surgical intervention. Careful neurological monitoring of these patients is essential, because some measures used to treat constipation can increase intracranial pressure. The objective of this report was to highlight constipation as a possible cause of transient VPS malfunction, thereby avoiding unnecessary surgical revisions, to which children with hydrocephalus are frequently submitted.

Novel cognitive insights from the first year after bi-thalamic infarct.

Neuropsychological consequences of bi-thalamic damage are scarcely known. This case study documents cognitive (in particular memory and executive) functioning in a man with a medial bi-thalamic infarct in the first year (8 and 12 months) post injury. NG showed persistent memory (including autobiographical) impairment, but improved executive functions at one year post injury. On a response inhibition task his speed of response improved but his ability to inhibit a "prepotent" automatic response declined, corresponding to an increase in behavioral disinhibition. Despite this, he showed intact performances on several social cognition tasks. This case contributes to our understanding of the role of the thalamus in mediating retrograde memory, executive, and social cognition functions.

Aggressive management of vasospasm with direct intra-arterial nimodipine therapy.

BACKGROUND: The conventional medical management of cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH) is associated with uncertainty of outcome and complications. AIMS AND OBJECTIVES: To examine the effect of direct intra-arterial nimodipine therapy on outcome in patients with delayed cerebral ischemia (DCI). SETTINGS AND DESIGN: The retrospective observational study was conducted at a single neurosurgical unit and interventional neuroradiolgy suite of a center managing SAH. MATERIALS AND METHODS: Data analysis of SAH managed surgically during the period from January 2014 through October 2015 was performed. Any decline in the neurological status on clinical examination, such as consciousness, motor and speech deficits, without other identifiable causes such as hydrocephalus, hyponatremia, seizure, intracranial hematoma, or infection, was used to define the presence of DCI. Patients with suspected DCI underwent computed tomography (CT) scan of the head followed by angiography. When vasospasm was detected in the absence of any major arterial territory infarct, the patients were managed with intra-arterial nimodipine therapy. The outcome at discharge was assessed. STATISTICAL ANALYSIS: Mid-P exact, two-tailed P value was used for categorical variables. RESULTS:: A total of 106 patients underwent surgical clipping of an aneurysm following SAH. DCI was diagnosed in 26 (24.5%) patients. Twenty three (88.5%) patients underwent intra-arterial nimodipine therapy. Angiographic response was seen in 22 (95.7%) patients and clinical response in 20 (87%) patients. At discharge, 19 patients (73.1%) with vasospasm had a favorable outcome. There was no significant difference in the outcome of patients with or without vasospasm. CONCLUSIONS: Aggressive management with intra-arterial nimodipine therapy is effective in preventing disability caused by DCI.

Effects of spatial attention on mental time travel in patients with neglect.

Numerous studies agree that time is represented in spatial terms in the brain. Here we investigate how a deficit in orienting attention in space influences the ability to mentally travel in time, that is to recall the past and anticipate the future. Right brain-damaged patients, with (RBD-N+) and without neglect (RBD-N-), and healthy controls (HC) were subjected to a Mental Time Travel (MTT) task. Participants were asked to project themselves in time to past, present or future (i.e., self-projection) and, for each self-projection, to judge whether events were located relatively in the past or the future (i.e., self-reference). The MTT-task was performed before and after a manipulation, through prismatic adaptation (PA), inducing a leftward shift of spatial attention. Before PA, RBD-N+ were slower for future than for past events, whereas RBD-N- and HC responded similarly to past and future events. A leftward shift of spatial attention by PA reduced the difference in past/future processing in RBD-N+ and fastened RBD-N- and HC's response to past events. Assuming that time concepts, such as past/future, are coded with a left-to-right order on a mental time line (MTL), a recursive search of future-events can explain neglect patients' performance. Improvement of the spatial deficit following PA reduces the recursive search of future events on the rightmost part of the MTL, facilitating exploration of past events on the leftmost part of the MTL, finally favoring the correct location of past and future events. In addition, the study of the anatomical correlates of the temporal deficit in mental time travel through voxel-based lesion-symptom mapping showed a correlation with a lesion located in the insula and in the thalamus. These findings provide new insights about the inter-relations of space and time, and can pave the way to a procedure to rehabilitate a deficit in these cognitive domains.

Supplementation with branched-chain amino acids ameliorates hypoalbuminemia, prevents sarcopenia, and reduces fat accumulation in the skeletal muscles of patients with liver cirrhosis.

BACKGROUND: Liver cirrhosis induces marked metabolic disorders, protein-energy malnutrition, and sarcopenia. The objective of the study reported here was to investigate the effects of dietary branched-chain amino acids (BCAAs) on systemic glucose metabolism, skeletal muscle, and prognosis of patients with liver cirrhosis. METHODS: Japanese patients with liver cirrhosis (n = 21) were enrolled into a longitudinal study in which their diets were supplemented with BCAAs. We evaluated glucose metabolism and analyzed the skeletal muscle area index (SAI) and intramuscular adipose tissue content (IMAC) using computed tomography. RESULTS: After 48 weeks of supplementation with BCAAs, there were no changes in glucose metabolism and skeletal muscle findings. In patients with ameliorated hypoalbuminemia, IMAC was significantly decreased and SAI was preserved concomitant with decreasing 90- and 120-min post-challenge plasma glucose levels (P < 0.01 each). In patients without increased albumin levels, IMAC was significantly increased and the SAI was significantly decreased (P < 0.01 each). Liver-related event-free survival rates for 72 months were 63.6% in patients with decreased IMAC and 20.0% in patients with increased IMAC. CONCLUSIONS: Amelioration of hypoalbuminemia associated with BCAA supplementation correlated with decreased fat accumulation in skeletal muscle, maintenance of skeletal muscle mass, and improved glucose sensitivity, all factors which may contribute to improving the survival of patients with liver cirrhosis.

Milk Basic Protein Facilitates Increased Bone Mass in Growing Mice.

Milk basic protein (MBP) comprises a group of basic whey proteins and is effective in preventing bone loss by promoting bone deposition (bone formation) and suppressing withdrawn (bone resorption). We previously revealed the bone protective effects of MBP during life phases involving excessive bone resorption, such as in adults and postmenopausal women, and in animal models (ovariectomized rats and mice). However, it was unclear whether MBP increases bone mass during the growth stage, when there is more bone formation than resorption. We therefore investigated the effect of MBP supplementation on bone mass in 6-wk-old mice provided water supplemented with MBP [0.01%, 0.1%, 1.0% (w/w)] or deionized water (control) ad libitum for 10 wk. Analysis by micro-computerized tomography showed that MBP significantly increased tibia cortical bone mineral density and femur trabecular bone volume to tissue volume compared with mice provided deionized water. Next, the function of MBP in bone remodeling (bone formation and resorption) was evaluated using an in vitro system and the results demonstrated that MBP directly promoted osteoblast proliferation and inhibited osteoclastogenesis. Moreover, the plasma level of insulin-like growth factor-1 was increased by MBP supplementation, suggesting that MBP indirectly promoted osteoblast proliferation/differentiation. These effects enhance bone formation and/or inhibit bone resorption, resulting in increased bone mass in growing mice.

Applications of a robotic stereotactic arm for pediatric epilepsy and neurooncology surgery.

OBJECTIVE The ROSA device is a robotic stereotactic arm that uses a laser system to register the patient's head or spine with MR or CT images. In this study, the authors analyze their experience with this system in pediatric neurosurgical applications and present selected cases that exemplify the usefulness of this system. METHODS The authors reviewed all cases that utilized the ROSA system at their institution. Patient demographics, pathology, complications, electrode placement, laser ablation, and biopsy accuracy were analyzed. Patient disposition and condition at follow-up were also analyzed. RESULTS Seventeen patients underwent 23 procedures using the ROSA system. A total of 87 electroencephalography electrodes were placed, with 13% deviating more than 3 mm from target. Six patients underwent stereotactic needle biopsy, and 9 underwent laser interstitial thermotherapy (LITT). One patient who underwent LITT required a subsequent craniotomy for tumor resection. Another patient experienced an asymptomatic extraaxial hematoma that spontaneously resolved. No patient suffered neurological complications during follow-up. Follow-up from the last procedure averaged 180 days in epilepsy patients and 309 days in oncology patients. CONCLUSIONS The precision, ease of use, and versatility of the ROSA system make it well suited for pediatric neurosurgical practice. Further work, including long-term analysis of results and cost-effectiveness, will help determine the utility of this system and if its applications can be expanded.

MSFCN-multiple supervised fully convolutional networks for the osteosarcoma segmentation of CT images.

BACKGROUND AND OBJECTIVE: Automatic osteosarcoma tumor segmentation on computed tomography (CT) images is a challenging problem, as tumors have large spatial and structural variabilities. In this study, an automatic tumor segmentation method, which was based on a fully convolutional networks with multiple supervised side output layers (MSFCN), was presented. METHODS: Image normalization is applied as a pre-processing step for decreasing the differences among images. In the frame of the fully convolutional networks, supervised side output layers were added to three layers in order to guide the multi-scale feature learning as a contracting structure, which was then able to capture both the local and global image features. Multiple feature channels were used in the up-sampling portion to capture more context information, for the assurance of accurate segmentation of the tumor, with low contrast around the soft tissue. The results of all the side outputs were fused to determine the final boundaries of the tumors. RESULTS: A quantitative comparison of the 405 osteosarcoma manual segmentation results from the CT images showed that the average Dice similarity coefficient (DSC), average sensitivity, average Hammoude distance (HM) and F1-measure were 87.80%, 86.88%, 19.81% and 0.908, respectively. It was determined that, when compared with the other learning-based algorithms (for example, the fully convolution networks (FCN), U-Net method, and holistically-nested edge detection (HED) method), the MSFCN had the best performances in terms of DSC, sensitivity, HM and F1-measure. CONCLUSION: The results indicated that the proposed algorithm contributed to the fast and accurate delineation of tumor boundaries, which could potentially assist doctors in making more precise treatment plans.