Retrieval of chromophore concentration changes in a digital human head model using analytical mean partial pathlengths of photons.

Significance: Continuous-wave functional near-infrared spectroscopy has proved to be a valuable tool for assessing hemodynamic activity in the human brain in a non-invasively and inexpensive way. However, most of the current processing/analysis methods assume the head is a homogeneous medium, and hence do not appropriately correct for the signal coming from the scalp. This effect can be reduced by considering light propagation in a layered model of the human head, being the Monte Carlo (MC) simulations the gold standard to this end. However, this implies large computation times and demanding hardware capabilities. Aim: In this work, we study the feasibility of replacing the homogeneous model and the MC simulations by means of analytical multilayered models, combining in this way, the speed and simplicity of implementation of the former with the robustness and accuracy of the latter. Approach: Oxy- and deoxyhemoglobin (HbO and HbR, respectively) concentration changes were proposed in two different layers of a magnetic resonance imaging (MRI)-based meshed model of the human head, and then these changes were retrieved by means of (i) a typical homogeneous reconstruction and (ii) a theoretical layered reconstruction. Results: Results suggest that the use of analytical models of light propagation in layered models outperforms the results obtained using traditional homogeneous reconstruction algorithms, providing much more accurate results for both, the extra- and the cerebral tissues. We also compare the analytical layered reconstruction with MC-based reconstructions, achieving similar degrees of accuracy, especially in the gray matter layer, but much faster (between 4 and 5 orders of magnitude). Conclusions: We have successfully developed, implemented, and validated a method for retrieving chromophore concentration changes in the human brain, combining the simplicity and speed of the traditional homogeneous reconstruction algorithms with robustness and accuracy much more similar to those provided by MC simulations.

Ultrasound Pattern of Cutis Verticis Gyrata.

Cutis verticis gyrata (CVG) is a cutaneous benign condition that usually presents symmetric or asymmetric convoluted folds and deep furrows in the scalp, which mimic the disposition of the cerebral sulci and gyri. This scalp deformation may be a worrying situation for the patients and their families. Clinically, its diagnosis may be challenging because it can mimic other cutaneous conditions. So far, the ultrasonographic pattern of CVG has not been reported. Thus, we aim to review the ultrasound findings of this entity. All patients (n = 14) presented zones with dermal and hypodermal thickening that corresponded with the elevated clinical zones, followed by folds with normal cutaneous thicknesses. There was undulation of the cutaneous layers in all cases. The scalp areas involved the frontal, parietal, and occipital regions bilaterally. The mean maximum dermal and hypodermal thicknesses and echogenicities and the color Doppler characteristics are provided. No significant dilation of the hair follicles was detected. In conclusion, CVG presents an ultrasonographic pattern that can support its diagnosis and follow-up. This can help its differential diagnosis with other scalp dermatologic conditions.

The parietal foramen anatomy: studies using dry skulls, cadaver and in vivo MRI.

OBJECTIVE: The aim of this study was to describe the anatomical features encountered in the parietal foramen in a series of 178 human bones and 123 head MRI examinations. A cadaveric specimen was also dissected to demonstrate the trajectory of a superficial scalp vein through the parietal foramen as far as the dura mater. A literature review was performed regarding prevalence of parietal foramen in different populations. METHODS: Totally, 178 paired adult bones were used to investigate the presence, shape and number of the parietal foramina. In addition, 123 brain MRI examinations were also studied. RESULTS: The parietal foramina were encountered in 75/89 (84.3%) skulls [32/38 (84.2%) in women vs. 43/51 (84.3%) in men, p > 0.05]. The parietal foramen was present bilaterally in 44.73% of females and 54.9% of males. Regarding unilaterality of the parietal foramen, a right or left laterality was observed in female 21% right versus 18% left; and 16% versus 14% (left) in males (p > 0.05). The accessory parietal foramen was present in the right parietal in 2.6% and in 7.9% on the left side of the females, while 5.9% and 3.9% of the males on the right or left sides, respectively. The parietal foramina located in the proximity of the sagittal suture (male 7.1 ± 2.5 mm vs. female, 7.4 ± 2.7 mm). There was a positive correlation between the right and left parietal foramina regarding the distance from the median line. The distance from a foramen to the contralateral one was 16 ± 4 mm in men and 18 ± 5 mm in women, respectively (p > 0.05). CONCLUSION: No major differences were encountered between sexes regarding the anatomical features of parietal foramen.

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.

Concordance among in vivo reflectance confocal microscopy, trichoscopy, and histopathology in the evaluation of scalp discoid lupus.

BACKGROUND: Reflectance confocal microscopy (RCM) has been used for the evaluation of several inflammatory skin conditions, including skin discoid lupus erythematosus (DLE), and has been correlated with conventional histopathology (HP). However, RCM is not being widely used in trichology. Few reports and just preliminary data suggest the use of RCM as a complementary tool in alopecias. OBJECTIVES: To correlate the major RCM features of scalp DLE with trichoscopy and HP findings of biopsy specimens obtained from the same lesions. METHODS: This is an observational, analytical, and cross-sectional study involving 12 patients with a clinically established diagnosis of scalp DLE. Patients underwent global clinical photograph, trichoscopy, and RCM examination in the same site followed by two 4-mm punch biopsy specimens for HP analysis. Inter-methods agreement among RCM imaging, trichoscopy, and horizontal histopathology sections (HHS) were calculated using Cohen Kappa (k) statistics. RESULTS: Statistical analysis of the agreement between RCM and HP features disclosed an overall agreement similar to skin DLE. Seven of the eleven features evaluated had agreement superior to 75%. We also evaluated RCM features associated with three of their corresponding trichoscopic findings for further investigation of their agreement with HP. Statistical analysis showed an enhancement with agreement of 86% when the non-invasive techniques are used together. CONCLUSION: Consistent correlation between RCM and HP observed in our study supports the reliability of RCM in the diagnosis of scalp DLE. RCM may be considered a promising tool for scalp DLE microscopic evaluation and presents similar RCM features to DLE in other body sites. By associating clinical, trichoscopic and RCM evaluation, dermatologists will have a non-invasive arsenal for the assessment of hair and scalp disorders, benefiting patients.

Proliferating trichilemmal cyst with clinical, radiological, macroscopic, and microscopic correlation.

Proliferating trichilemmal cyst is an uncommon neoplasm arising from the follicular isthmus, whose histopathological hallmark is the presence of trichilemmal keratinization. We describe a case of proliferating trichilemmal cyst in a 57-year-old woman with a broad clinical, radiological, macroscopic and microscopic correlation.

Proliferating trichilemmal cyst with clinical, radiological, macroscopic, and microscopic correlation

Abstract: Proliferating trichilemmal cyst is an uncommon neoplasm arising from the follicular isthmus, whose histopathological hallmark is the presence of trichilemmal keratinization. We describe a case of proliferating trichilemmal cyst in a 57-year-old woman with a broad clinical, radiological, macroscopic and microscopic correlation.

Ventriculosubgaleal shunting-a comprehensive review and over two-decade surgical experience.

INTRODUCTION: The subgaleal space is the fibroareolar layer found between the galea aponeurotica and the periosteum of the scalp. Due to its elastic and absorptive capabilities, the subgaleal space can be used as a shunt to drain excess cerebrospinal fluid from the ventricles. A subgaleal shunt consists of a shunt tube with one end in the lateral ventricles while the other end is inserted into the subgaleal space of the scalp. This will allow for the collection and absorption of excess cerebrospinal fluid. Indications for ventriculosubgaleal shunting (VSG) include acute head trauma, subdural hematoma, and malignancies. DISCUSSION: VSG shunt is particularly advantageous for premature infants suffering from post-hemorrhagic hydrocephalus due to their inability to tolerate long-term management such as a ventriculoperitoneal shunt. Complications include infection and shunt blockage. In comparison with other short-term treatments of hydrocephalus, the VSG exhibits significant advantages in the drainage of excess cerebrospinal fluid. VSG shunt is associated with lower infection rates than other external ventricular drain due to the closed system of CSF drainage and lack of external tubes. CONCLUSION: This review discusses the advantages and disadvantages of the VSG shunt, as well as our personal experience with the procedure.

Lichen simplex chronicus on the scalp: exuberant clinical, dermoscopic, and histopathological findings.

Lichen simplex chronicus is a skin disease that mostly affects female patients, with a peak incidence between ages 35 and 50 years. On the scalp, it appears as a single or multiple oval lesions, showing scaling and hair shaft loss or breakage. An important dermoscopic feature of the disease are the "broom fibers." Histopathology reveals the "hamburger" and the "gear wheel" signs. The aim of this report is to demonstrate a case of lichen simplex chronicus on the scalp with typical and exuberant clinical, dermoscopic, and histopathological findings.

Lichen simplex chronicus on the scalp: exuberant clinical, dermoscopic, and histopathological findings

Abstract: Lichen simplex chronicus is a skin disease that mostly affects female patients, with a peak incidence between ages 35 and 50 years. On the scalp, it appears as a single or multiple oval lesions, showing scaling and hair shaft loss or breakage. An important dermoscopic feature of the disease are the "broom fibers." Histopathology reveals the "hamburger" and the "gear wheel" signs. The aim of this report is to demonstrate a case of lichen simplex chronicus on the scalp with typical and exuberant clinical, dermoscopic, and histopathological findings.

Circular hairs: nomenclature and meanings.

Trichoscopy has become an essential tool for the diagnosis of various diseases that affect the hair and scalp. Through dermatoscopy we identified a set of findings that share a circular shape of hair shafts. The objective of this study is to distinguish among the various forms of circular hairs in order to identify their peculiarities and to describe in which skin disorders they can be found.

Sonography in pathologies of scalp and hair.

Disorders of the scalp often result in severe cosmetic interference with quality of life, creating the need for optimal medical surveillance. We tested the latest generation of ultrasound machines in patients with scalp pathology and prepared a cross-sectional library encompassing a wide assortment of conditions. Normative data on the sonographic anatomy of scalp and human hair, and important methodological considerations, are also included.

Fetal scalp cyst or small meningocele: differential diagnosis with three-dimensional ultrasound.

BACKGROUND: Prenatal differential diagnosis of fetal scalp cystic masses is challenging and mainly includes small meningoceles and epidermal cysts. CASE: A second-trimester anatomy scan revealed an extracranial cystic mass measuring 17 × 12 × 10 mm in the fetal occipital region. Three-dimensional datasets were obtained transabdominally and off-line analysis revealed a connection between the cyst and the subarachnoid space through a 5-mm skull defect. The diagnosis of a small meningocele was further confirmed by magnetic resonance imaging in the infant. CONCLUSION: Prenatal three-dimensional ultrasound can be a useful adjunct in the prenatal differentiation between small meningoceles and epidermal cysts.

Prenatal diagnosis of 48,XYY, +21 ascertained through ultrasound anomalies.

During a routine ultrasound study on a fetus at 21 weeks, nuchal edema was noted. At 21 weeks, repeat ultrasound study at our unit showed scalp and neck edema and a femur length/biparietal diameter ratio below the mean. Transabdominal chorionic villus sampling identified a 48.XYY, +21 chromosome constitution. The fetus had normal internal/external genitalia and signs of Down syndrome.