Correspondence between scalp-EEG and stereoelectroencephalography seizure-onset patterns in patients with MRI-negative drug-resistant focal epilepsy.

OBJECTIVE: Our objective was to evaluate the relationship between scalp-EEG and stereoelectroencephalography (SEEG) seizure-onset patterns (SOP) in patients with MRI-negative drug-resistant focal epilepsy. METHODS: We analyzed retrospectively 41 patients without visible lesion on brain MRI who underwent video-EEG followed by SEEG. We defined five types of SOPs on scalp-EEG and eight types on SEEG. We examined how various clinical variables affected scalp-EEG SOPs. RESULTS: The most prevalent scalp SOPs were rhythmic sinusoidal activity (56.8%), repetitive epileptiform discharges (22.7%), and paroxysmal fast activity (15.9%). The presence of paroxysmal fast activity on scalp-EEG was always seen without delay from clinical onset and correlated with the presence of low-voltage fast activity in SEEG (sensitivity = 22.6%, specificity = 100%). The main factor explaining the discrepancy between the scalp and SEEG SOPs was the delay between clinical and scalp-EEG onset. There was a correlation between the scalp and SEEG SOPs when the scalp onset was simultaneous with the clinical onset (p = 0.026). A significant delay between clinical and scalp discharge onset was observed in 25% of patients and featured always with a rhythmic sinusoidal activity on scalp, corresponding to similar morphology of the discharge on SEEG. The presence of repetitive epileptiform discharges on scalp was associated with an underlying focal cortical dysplasia (sensitivity = 30%, specificity = 90%). There was no significant association between the scalp SOP and the epileptogenic zone location (deep or superficial), or surgical outcome. SIGNIFICANCE: In patients with MRI-negative focal epilepsy, scalp SOP could suggest the SEEG SOP and some etiology (focal cortical dysplasia) but has no correlation with surgical prognosis. Scalp SOP correlates with the SEEG SOP in cases of simultaneous EEG and clinical onset; otherwise, scalp SOP reflects the propagation of the SEEG discharge. PLAIN LANGUAGE SUMMARY: We looked at the correspondence between the electrical activity recorded during the start of focal seizure using scalp and intracerebral electrodes in patients with no visible lesion on MRI. If there is a fast activity on scalp, it reflects similar activity inside the brain. We found a good correspondence between scalp and intracerebral electrical activity for cases without significant delay between clinical and scalp electrical onset (seen in 75% of the cases we studied). Visualizing repetitive epileptic activity on scalp could suggest a particular cause of the epilepsy: a subtype of brain malformation called focal cortical dysplasia.

Does preoperative imaging for scalp non-melanocytic skin cancer accurately predict invasion of the cranial vault? A systematic review and meta-analysis.

PURPOSE: This study aimed to determine the diagnostic accuracy of CT and MRI in the preoperative detection of bone involvement for non-melanoma skin cancers (NMSCs) located on the scalp. This study further aimed to evaluate the predictive value of these imaging modalities in determining the need for craniectomy and to identify gaps in the existing literature. METHODS: Electronic searches of the MEDLINE, Embase, Cochrane and Google Scholar databases were performed for English language studies of any type. Studies reporting detection or exclusion of histopathologically confirmed bone involvement through preoperative imaging were identified according to PRISMA guidelines. Studies reporting dural involvement, non-scalp tumours, and lacking tumour type(s) or outcome data were excluded. Outcomes were preoperative imaging result and histopathologically confirmed bone invasion. Meta-analysis was performed and sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated (excluding case report and MRI data due to insufficient quality and quantity respectively). RESULTS: Four studies with a total of 69 patients were included in the final review, of which two studies totalling 66 patients were included in the meta-analysis. Preoperative CT had a sensitivity of 38%, specificity of 98%, PPV of 90% and NPV of 73%. CONCLUSIONS: The available data suggests that a preoperative CT finding of calvarial involvement by a scalp NMSC is likely to be real, but the absence of such a finding is unreliable. Current evidence suggests that preoperative imaging cannot exclude the necessity for craniectomy and future research is needed, particularly on the role of MRI.

Intracranial posterior fossa proliferating trichilemmal tumor: first case report.

Proliferating trichilemmal tumors (PTT) are rare benign lesions that predominantly occur in elderly women and usually affect the scalp. They originate from the outer root sheath of hair shafts and have trichilemmal differentiation on histopathological examination. Compared to trichilemmal cysts, PTTs show increased cell proliferation and variable cytological atypia. We report the first case of a patient with an intracranial PTT in the posterior fossa. The clinicoradiological presentation and surgical management of the patient as well as the possible pathogenesis of this tumor are discussed.

An Investigation into the Correlation of Scalp Electrophysiological Findings with Preoperative Clinical and Imaging Findings in Patients with Focal Cortical Dysplasia.

AIM: To evaluate the patients who had epilepsy surgery and pathologically proven focal cortical dysplasia (FCD) in order to further classify and discuss electroencephalography (EEG) findings in different pathological subtypes. MATERIAL AND METHODS: This study included 19 refractory epilepsy patients who underwent surgery between 1999 and 2017 in the Istanbul Faculty of Medicine. Demographic data, preoperative examinations, scalp video EEGs, and postoperative outcomes were evaluated retrospectively. RESULTS: In this study, 36.8% of the patients were female. The mean age was 21.89 ± 14.64 years. Rhythmic epileptiform discharges (RED) were observed in 31.6%. 37.5% of the patients with isolated intermittent spike/sharp waves were type I, 50% were type II, and 12.5% were type III. 100% of the patients with normal background activity were FCD type II. 67% of the patients with asymmetric slowing were FCD type I, 22% was FCD type II, 11% were FCD type III. 71% of the patients with symmetrical slowing were FCD type I, 29% were FCD type II. One patient had Frontal Intermittent Rhythmic Activity, one patient had Electrical Status Epilepticus in Slow Sleep, two patients had "burst suppression," and one patient had a "switch of" sign. The frequency of focal epileptogenic activity was higher when there was an FCD lesion on magnetic resonance imaging. CONCLUSION: The findings obtained in this study did not reveal any distinctive electrophysiological features in FCD and subgroups of FCD. The incidence of REDs did not differ between types. The frequency of isolated intermittent sharp/spike waves was higher in type II than I. Intermittent and continuous EEG slowing was more commonly seen among FCD Type I patients.

[Clinical application analysis of a method for locating scalp projection of intracranial lesions based on neuroimaging].

Objective: To explore the feasibility of a method based on neuroimaging and surface markers for locating scalp projection of intracranial lesions. Methods: The clinical data of 46 patients who were used 'double-circle method' for locating scalp projection of intracranial lesions at Department of Neurosurgery,the First Affiliated Hospital of Xiamen University from January to June 2021 were retrospective analyzed. All patients with 2 electrodes(artificial fiducials) randomly attached to scalp had been examed thin-layer brain CT. The distances from the center of each fiducial to the root of the nose and tragus were measured through the images. A compass was used to draw two arcs with the root of nose and the tragus as the center and the pre-measured distance as the radius on patient's scalp. Then two arcs' intersection on the scalp was the fiducial. The method was named 'double-circle method'. Two neurosurgeons were arranged to perform fiducial identification with double-circle method, and record the error between the result and the actual fiducial point.Independent sample t test was used for data comparison, and Kappa test was used to analysis the inter-group consistency. Results: Ninety-two fiducial points of 46 patients were collected. Time consuming of doctor A was (8.1±2.3) minutes(range:5 to 15 minutes)and doctor B was (8.9±3.5) minutes(range:4 to 17 minutes).The positioning error from the doctor A was (4.4±2.4)mm(range:0 to 12 mm) and doctor B was(4.2±2.6) mm(range:0 to 14 mm)(t=-0.575,P=0.567),the difference was not statistically significant. The Kappa value of the consistency test of error between two doctors was 0.517(P=0.001).The consistency was moderate.Eight patients used 'double-circle method' and neuronavigation for locating scalp projection of intracranial lesions at the same time. The diameter of the lesions was (3.8±0.9)cm (range: 2.6 to 5.1 cm), and the positioning error of the 'double-circle method' and navigation was (4.0±1.9) mm(range: 1 to 6 mm), and all patients were confirmed to be accurately located during surgery. Conclusion: 'Double-circle method' is a simple,convenient and accurate way in locating intracranial lesions and has certain clinical significance.

Real-time augmented reality application in presurgical planning and lesion scalp localization by a smartphone.

OBJECTIVE: A smartphone augmented reality (AR) application (app) was explored for clinical use in presurgical planning and lesion scalp localization. METHODS: We programmed an AR App on a smartphone. The accuracy of the AR app was tested on a 3D-printed head model, using the Euclidean distance of displacement of virtual objects. For clinical validation, 14 patients with brain tumors were included in the study. Preoperative MRI images were used to generate 3D models for AR contents. The 3D models were then transferred to the smartphone AR app. Tumor scalp localization was marked, and a surgical corridor was planned on the patient's head by viewing AR images on the smartphone screen. Standard neuronavigation was applied to evaluate the accuracy of the smartphone. Max-margin distance (MMD) and area overlap ratio (AOR) were measured to quantitatively validate the clinical accuracy of the smartphone AR technique. RESULTS: In model validation, the total mean Euclidean distance of virtual object displacement using the smartphone AR app was 4.7 ± 2.3 mm. In clinical validation, the mean duration of AR app usage was 168.5 ± 73.9 s. The total mean MMD was 6.7 ± 3.7 mm, and total mean AOR was 79%. CONCLUSIONS: The smartphone AR app provides a new way of experience to observe intracranial anatomy in situ, and it makes surgical planning more intuitive and efficient. Localization accuracy is satisfactory with lesions larger than 15 mm.

Trichoscopy may enhance the differential diagnosis of erythroderma.

There is a paucity of data concerning the usefulness of trichoscopy in patients with erythroderma. The aim of the study was to compare the trichoscopic features in erythroderma of various aetiologies. In total, 49 patients with a determined cause of erythroderma [including atopic dermatitis (AD), mycosis fungoides (MF), allergic contact eczema (ACE), psoriasis (Pso), Sézary syndrome (SS), drug reaction, pityriasis rubra pilaris (PRP), dermatomyositis (DM), actinic reticuloid (AR), crusted scabies (CS) and pemphigus foliaceus (PF)] were included in the study. Dotted vessels were present in patients with AD, PRP, MF, SS and Pso, and absent in DM, CS and PF (χ², P < 0.02). Spermatozoon-like vessels were observed only in MF and SS (P = 0.001). Whitish-pinkish structureless areas were described in all patients with DM, AR and CS (P < 0.03). The type of vessel and the presence of whitish-pinkish structureless areas under trichoscopy may indicate the cause of erythroderma.

18F-FDG PET Uptake in the Scalp After Platelet-Rich Plasma Therapy.

ABSTRACT: 18F-FDG PET/CT has been found useful for the detection of the source of infection/inflammation in the body. Platelet-rich plasma is a new treatment modality in which plasma is injected subdermally or intradermally for potential hair regrowth into the scalp. We report a case of 43-year-old woman with right breast cancer who underwent surgery, chemotherapy, and radiotherapy 2 years ago and is currently on hormonal therapy. 18F-FDG PET/CT demonstrate incidental findings of increased FDG avidity in the scalp after platelet-rich plasma therapy.

Assessing the accuracy of computed tomography in detecting bony invasion and thickness of squamous cell carcinoma of the scalp.

OBJECTIVES: The aim of this study was to ascertain the accuracy of computed tomography (CT) in assessing the presence of bony involvement and thickness of squamous cell carcinoma (SCC) of the scalp. METHODS: A single-centre retrospective chart review was carried out. Inclusion criteria were scalp SCC, CT between January 2008 and 2018, and the availability of a reference test. Reference tests were either histology, surgical notes or clinical notes. Tabular assessment of accuracy was performed and Student's t-test, Mann-Whitney U test and Fisher exact test were used in univariable analysis. Accuracy of thickness measurement was calculated using the limits of agreement method, and linear regression was used to examine trend. RESULTS: Thirty-nine patients were included. Most patients were male (74.4%), white (97.4%), not immunosuppressed (66.6%) and had poorly differentiated tumours (33.3%). The most common tumour sites were the vertex (28.2%) and temporal region (23.1%). Sensitivity of CT in detecting presence or absence of bony invasion of scalp SCC was 76.9% (95% CI 46.2-94.9%) and specificity was 96.2% (95% CI 80.4-99.9%). Overall accuracy was 89.7% (95% CI 75.8-97.1%), positive predictive value was 90.1% (95% CI 58.7-99.8%) and negative predictive value was 89.3% (95% CI 71.8-97.7%). No significant differences were found comparing patients with an accurate or inaccurate CT scan. Thickness on CT was found to be consistent with histological thickness at the 95% confidence level. CONCLUSIONS: CT is accurate at assessing the presence of bony involvement and thickness of scalp SCC. This study was limited somewhat by small sample size.

Dosimetric comparison of volumetric modulated arc therapy (VMAT) and high-dose-rate brachytherapy (HDR-BT) for superficial skin irradiation with significant curvature in one or more planes.

PURPOSE: This study compares the plan quality of high-dose-rate brachytherapy (HDR-BT) and volumetric modulated arc therapy (VMAT) for superficial irradiation of large areas of skin with significant curvature in one or more planes. METHODS: A total of 14 patients from two centres previously treated with either HDR-BT or VMAT were retrospectively replanned using the alternative technique. Sites included scalp and lower limbs. Identical computed tomography (CT) scans, clinical target volume (CTV) and organs at risk (OARs) and prescription were used for both techniques. Conformity, skin surface dose and OAR doses were compared. RESULTS: Conformity index was consistently better with VMAT than HDR-BT (p < 0.01). Maximum skin surface dose (D0.1cc) had a higher mean of 49.6 Gy with HDR-BT compared to 31.4 Gy for VMAT (p < 0.01). Significantly smaller volumes of healthy tissue were irradiated with VMAT than with HDR-BT. This can be seen in brain volumes receiving 10, 20 and 30 Gy EQD2 and in extremities receiving 5 and 10 Gy. When close to the volume, the lens received significantly lower doses with VMAT (p < 0.01). CONCLUSION: In this small sample, VMAT gives equal coverage with lower OAR and skin surface doses than HDR-BT for both scalp and extremities. VMAT is a useful technique for treating large, superficial volumes with significant curvature in one or more planes.

Imaging findings of cutaneous angiosarcoma of the scalp: Comparison with cutaneous squamous cell carcinoma.

PURPOSE: This study aimed to evaluate imaging findings of cutaneous angiosarcoma (cAS) of the scalp compared with those of cutaneous squamous cell carcinoma (cSCC). METHODS: This study included 15 patients with primary cAS and 10 with primary cSCC of the scalp. Seven patients with cAS and eight with cSCC underwent magnetic resonance imaging, and 11 patients with cAS and eight with cSCC underwent 18F-fluorodeoxyglucose-positron emission tomography/computed tomography imaging. Imaging findings for both pathologies were retrospectively reviewed and compared. RESULTS: All 15 cAS cases were elevated lesions with an obtuse angle, invading the subcutaneous fat tissue. Multiple lesions were observed in only five cAS cases (33%) and no cSCC cases. Maximum diameter-to-height ratio was significantly higher in cAS than in cSCC (3.3 ± 1.0 versus 2.3 ± 0.6; p < 0.01). On T2-weighted images, intratumoral hypointensity (86% versus 13%; p < 0.01) and mixed hyper- and hypointensity (71% versus 0%; p < 0.01) were observed more frequently in cAS than in cSCC. No significant differences were observed between cAS and cSCC regarding flow void (29% versus 25%; p = 0.656). Maximum standardized uptake values were marginally significantly lower in cAS than in cSCC (5.6 ± 3.1 versus 10.5 ± 6.6; p = 0.078). CONCLUSIONS: Cases of cAS of the scalp always exhibited flat elevated lesions with invasion of the subcutaneous fat tissue. Compared with cSCC, intratumoral hypointensity and mixed hyper- and hypointensity on T2-weighted images were more frequent in cAS. These findings will help with the differential diagnosis of cAS.

Multimodality imaging and treatment strategy for malignant scalp neoplasms in adults.

Malignant scalp masses deserve much attention as they have the potential to destroy local structures, recur and metastasize to distant organs. Moreover, malignant scalp lesions are known to be more aggressive in behavior than their counterparts elsewhere in the body. Multimodality imaging is essential in narrowing the differential diagnoses of scalp masses, as well as in differentiating benign from malignant masses. Furthermore, imaging is important in (1) evaluating the extent of tumor invasion in the scalp, (2) staging the disease, (3) guiding surgical biopsy and/or resection of the tumor, (4) preoperative planning and post-treatment surveillance of scalp tumors. An interdisciplinary treatment approach is crucial for the management of scalp malignancies given their complex and aggressive nature. This review seeks to describe the unique clinical and imaging characteristics of various types of malignant scalp masses, as well as to review their current treatment strategies.

Cutaneous T-cell lymphoma in erythrodermic cases may be suspected on the basis of scalp examination with dermoscopy.

Erythrodermic variants of cutaneous T-cell lymphoma (CTLC) are one of the case of erythroderma. The aim of the study was to assess the value of scalp dermoscopy in differentiation between erythrodermic CTCL, psoriasis, and atopic dermatitis. A total of 76 patients were included into the study (16 patients with erythrodermic CTCL, 20 patients with psoriatic erythroderma, 20 with erythrodermic atopic dermatitis, and 20 healthy volunteers). The most common trichoscopic features of erythrodermic CTCL were: numerous pili torti, numerous broken hairs, white thick interfollicular bands, and patchy hyperpigmentation of the background. They were observed in 81% (13/16), 75% (12/16), 56% (9/16), and 37.5% (6/16) of patients with CTCL, respectively (p < 0.001). Other specific features of erythrodermic CTCL were 8-shaped hairs (19%; 3/16) and visible anagen bulbs (12.5%; 2/16) (p < 0.05 and p = 0.052, respectively). The most common vascular pattern of erythrodermic CTCL was perifollicular arrangement of glomerular (50%; 8/16; p < 0.001) or linear vessels (31%; 5/16; p < 0.05). Follicular spicules-like scaling was pathognomonic for erythrodermic CTCL (12%, 2/16) although its presence did not reach statistical significance (p = 0.052). In conclusion, the characteristic trichoscopic findings of erythrodermic CTCL are numerous pili torti, eight-shaped hairs, thick white interfollicular bands, color heterogeneity of the background and perifollicular arrangement of vessels.

Primary Epithelioid Sarcoma Manifesting as a Fungating Scalp Mass - Imaging Features and Treatment Options. A Case Report and Literature Review.

Primary epithelioid sarcoma is an extremely rare malignancy of the scalp. To date, less than a dozen such cases have been reported in the literature. The diagnosis often is a challenge to both radiologists and clinicians. This is largely attributed to the lack of literature on the imaging features of scalp epithelioid sarcoma. In this report, we highlight the role of multimodality imaging in the diagnosis of primary scalp epithelioid sarcoma and review the epidemiology, imaging, treatment options, and prognosis of these malignant scalp tumors. Displaying a multilobulated morphology, heterogeneous enhancement, and restricted diffusion on MRI, these tumors typically show central degeneration with hemorrhage, necrosis, and calcification. Wide surgical resection and adjuvant radiotherapy are the mainstays of treatment for localized scalp tumors. Nevertheless, the prognosis of patients with distant metastases at diagnosis is extremely poor compared to those with local or regional diseases.

Ultrasound Imaging of Nevus Sebaceous of Jadassohn.

Nevus sebaceous of Jadassohn (NSJ) is a cutaneous hamartoma commonly found in the scalp and face and more frequent in children. Clinically, it presents as a yellowish and hairless plaque. In later stages, the NSJ can develop secondary tumors, including skin cancer. We reviewed the ultrasound characteristics of 9 patients (67% female; mean age, 3 years) with NSJ at 18 and 70 MHz. The ultrasound analysis covers the data on the location, thickness, echo structure, and vascularity. The provision of the ultrasound patterns of NSJ can support early diagnosis, avoid unnecessary biopsies, and support monitoring.

Optical Coherence Tomography in the Evaluation of the Scalp and Hair: Common Features and Clinical Utility.

BACKGROUND AND OBJECTIVE: Early diagnosis and treatment of hair loss disorders is vital in providing patients with improved psychological outcomes. Non-invasive imaging with optical coherence tomography (OCT) may be useful in characterizing and managing alopecia. Despite expanding clinical applications of OCT in dermatology, guidelines demonstrating in vivo features of normal and alopecic scalp images remain scant. This pilot study aims to provide an atlas of OCT findings of healthy and alopecia subjects, explore diagnostic quantitative endpoints of alopecia, and compare epidermal thickness and follicular density between scalp regions. STUDY DESIGN/MATERIALS AND METHODS: A total of 32 patients (19-76 years old) were enrolled in the study, including healthy patients (n = 6), and patients with scarring alopecia (n = 12) or non-scarring alopecia (n = 14). An in-line fiber-based swept source OCT was used to image five scalp locations at baseline and 6-month visits. Three investigators evaluated each image for gross features, epidermal thickness, and follicular density. RESULTS: Only data from baseline imaging analysis is discussed in this manuscript. Qualitative differences of OCT images are identified in sample images from healthy scalp and each subtype of alopecia studied. Scarring alopecia is characterized by significantly increased epidermal thickness (average Image J pixel units 32 ± 2 compared with non-scarring alopecia [average 28 ± 3] and control [average 27 ± 3]) (P = 0.022) and decreased follicle count (average 35 ± 5 in a 5 × 7 mm2 area compared with control (50 ± 3) and non-scarring patients (47 ± 6)) (P = 0.0052). Scalp location had no impact on epidermal thickness (P = 0.861) or follicular density (P = 0.15). CONCLUSION: OCT holds promise as a non-invasive technique to further characterize and objectively measure alopecia. Larger sample sizes and longitudinal data are needed to improve reliability and determine if additional distinction between alopecia subtypes and treatment monitoring is possible. Lasers Surg. Med. © 2020 Wiley Periodicals, Inc.

Combining Deep Learning With Optical Coherence Tomography Imaging to Determine Scalp Hair and Follicle Counts.

BACKGROUND AND OBJECTIVES: One of the challenges in developing effective hair loss therapies is the lack of reliable methods to monitor treatment response or alopecia progression. In this study, we propose the use of optical coherence tomography (OCT) and automated deep learning to non-invasively evaluate hair and follicle counts that may be used to monitor the success of hair growth therapy more accurately and efficiently. STUDY DESIGN/MATERIALS AND METHODS: We collected 70 OCT scans from 14 patients with alopecia and trained a convolutional neural network (CNN) to automatically count all follicles present in the scans. The model is based on a dual approach of both detecting hair follicles and estimating the local hair density in order to give accurate counts even for cases where two or more adjacent hairs are in close proximity to each other. RESULTS: We evaluate our system on 70 OCT manually labeled scans taken at different scalp locations from 14 patients, with 20 of those redundantly labeled by two human expert OCT operators. When comparing the individual human predictions and considering the exact locations of hair and follicle predictions, we find that the two human raters disagree with each other on approximately 22% of hairs and follicles. Overall, the deep learning (DL) system predicts the number of follicles with an error rate of 11.8% and the number of hairs with an error rate of 18.7% on average on the 70 scans. The OCT system can capture one scalp location in three seconds, and the DL model can make all predictions in less than a second after processing the scan, which takes half a minute using an unoptimized implementation. CONCLUSION: This approach is well-positioned to become the standard for non-invasive evaluation of hair growth treatment progress in patients, saving significant amounts of time and effort compared with manual evaluation. Lasers Surg. Med. © 2020 Wiley Periodicals, Inc.