Thermal finite element analysis of localized hypothermia treatment of the human eye

Localized hypothermia treatment can reduce the risk of vision loss due to ocular trauma. Hypothermia reduces inflammation and metabolic rate, and improves blood flow to prevent nerve and tissue damage. This paper presents a finite element thermal analysis to determine the efficacy of local hypothermia treatment administered using a scleral eye contact ring that acts as a heat sink. A realistic model of the human eye orbit, including fat and muscle, is created using MRI scans. A simplified CAD-based model is also created based on the first model. A transient analysis is performed by lowering the contact surface between the device and the eye to 4^∘C. The study shows that the device lowers the temperature of the optic nerve head to a therapeutic range of 32-34^∘C in less than 10 min of treatment, hence supporting the efficacy of such a device.

Autonomous cortisol secretion in adrenal incidentalomas and increased visceral fat accumulation during follow-up

OBJECTIVE

Autonomous cortisol secretion of adrenal incidentalomas (AIs) is associated with poor cardiovascular outcome. Because centripetal obesity is a cardiovascular risk factor, we aimed to investigate whether autonomous cortisol secretion is associated with increased visceral fat accumulation.

DESIGN

Retrospective cohort study.

PATIENTS

Patients with AIs who attended for follow-up between January 2014 and December 2016 were evaluated. Autonomous cortisol secretion was diagnosed when 1 mg overnight dexamethasone (post-DST) cortisol was >50 nmol/L at baseline and follow-up. Follow-up duration was 34 (12-105) months. Thirty patients with nonfunctioning AIs and 44 patients with autonomous cortisol secretion were included. Adrenalectomy was performed in five patients. Six patients with Cushing's syndrome were also recruited.

MEASUREMENTS

Hormonal evaluation and assessment of total (T), visceral (V) and subcutaneous (S) fat area by computed tomography and calculation of V:S and V:T ratios at baseline and follow-up.

RESULTS

V, V:S and V:T increased (P<.001 for each comparison, Wilcoxon signed rank test for repeated measures) in patients with autonomous cortisol secretion while did not change significantly in patients with nonfunctioning adenomas. Linear regression models including post-DST cortisol, gender, concomitant treatments and follow-up duration showed that both baseline and follow-up DST significantly predicted Δ(V:S) and Δ(V:T) (P<.01 for all models).

CONCLUSIONS

In patients with AIs, a post-DST cortisol >50 nmol/L at both baseline and follow-up, was associated with a significant increase in visceral fat after a follow-up duration of ~3 years. This may be of importance to explain the link between autonomous cortisol secretion and poor cardiovascular outcome.

Incomplete endochondral ossification of the otic capsule, a variation in children: evaluation of its prevalence and extent in children with and without sensorineural hearing loss

BACKGROUND AND PURPOSE

Endochondral ossification of the otic capsule is a process that continues postnatally; hence, incomplete endochondral ossification is seen as pericochlear hypoattenuation on temporal bone CT scans of children. We determined the prevalence and extent of this entity in a large series and assessed its relation to age and underlying sensorineural hearing loss.

MATERIALS AND METHODS

Initially, temporal bone CTs of 40 children with sensorineural hearing loss were retrospectively assessed and compared with those of a control group scanned for non-sensorineural hearing loss reasons to assess any difference in the prevalence or extent of incomplete endochondral ossification. Then the CT scans of 510 children (age range, 17 days to 17 years) were retrospectively reviewed, and any observed endochondral ossification areas were classified as mild, moderate, or extensive, according to their extent.

RESULTS

Neither the presence nor degree of incomplete endochondral ossification had any significant correlation with the presence of sensorineural hearing loss (P = .08 and P = .1, respectively). Incomplete endochondral ossification was more frequently seen (62% of cases) than complete ossification. There was no statistically significant correlation between incomplete endochondral ossification and sex (P = .8), but an inverse correlation was found between the presence of incomplete endochondral ossification and increasing age (P < .001). Overall, mild incomplete endochondral ossification was the most frequent involvement pattern (44.4%).

CONCLUSIONS

The pericochlear hypoattenuation in the otic capsule representing incomplete endochondral ossification is a normal finding in children and can be seen as a marked curvilinear hypoattenuation at younger ages in the absence of any clinical disorder.

Radiographic manifestations of the temporomandibular joint in a case of Proteus syndrome

Proteus syndrome is a rare disorder with progressive asymmetrical and disproportionate overgrowth of various tissues of the body. The syndrome is characterized by a wide range of malformations, including craniofacial deformities. Extraoral examination revealed several of the classical craniofacial features of Proteus syndrome: pronounced hemifacial hypertrophy, macrodactyly and hyperostosis. Intraoral examination revealed a high arched palate and gingival hyperplasia. Other findings were unilateral enlargement of the tongue, alveolar growth and dilaceration of the roots of the teeth. There were severe degenerative changes and deformities in the left temporomandibular joint but the oversized condyle was asymptomatic; there was no pain, limitation and deviation at mouth opening. Treatment was not necessary owing to the asymptomatic situation but periodic follow-up with clinical and radiographic examination was considered. The aim of this article is to describe the radiographic manifestations of an asymptomatic condyle malformation and other craniofacial, oral and dental findings in a 33-year-old female patient with known Proteus syndrome.

Maxillofacial osteosarcoma successfully treated with surgery and adjuvant chemotherapy in a child

Maxillofacial osteosarcoma constitutes a minor percentage of all the head and neck tumors. We describe a 10 year-old girl presenting with swelling and pain in left maxillary region and diagnosed as low grade osteosarcoma. The patient was operated and given a chemotherapy protocol consisted of Cisplatin and Doxorubicin. After six courses of chemotherapy the patient was in complete remission and she is well with no evidence of disease for five years. Since high local recurrence rates have been reported in craniofacial osteoarcoma and we know the deleterious side effects of radiation therapy in children, we believe that best management strategy for osteosarcomas in maxillofacial region in children is radical surgical excision and postoperative chemotherapy (Fig. 3, Ref. 11).

Diffusion MR imaging features of skull base osteomyelitis compared with skull base malignancy

BACKGROUND AND PURPOSE

SBO is a life-threatening infection that may have radiologic features similar to those of the neoplastic processes. The purpose of this study was to evaluate the DWI findings in SBO to facilitate the differential diagnosis.

MATERIALS AND METHODS

The MR imaging findings of 9 patients with SBO were retrospectively evaluated and compared with MR imaging studies from 9 patients with NPC, 9 with lymphoma, and 9 with metastatic disease of the skull base. ADC measurements were performed from the ADC(ST) and the ADC(NST) in all 4 groups.

RESULTS

The mean ADC(ST) values were 1.26 ± 0.19 × 10(-3) mm(2)/s for SBO, 0.74 ± 0.18 × 10(-3) mm(2)/s for NPC, 0.59 ± 0.11 × 10(-3) mm(2)/s for lymphoma, and 0.99 ± 0.34 × 10(-3) mm(2)/s for metastatic disease, respectively. The mean ADC value of SBO was significantly higher than those of NPC and lymphoma (P < .0001). There was no significant difference for the comparison of SBO and metastatic lesions. When an ADC value equal to or higher than 1.08 × 10(-3) mm(2)/s was used to rule out lymphoma and NPC, the accuracy was 96%.

CONCLUSIONS

Although SBO is a relatively rare condition, its differential diagnosis from neoplastic processes of the skull base is essential to start appropriate treatment promptly. ADC values may help to distinguish patients with SBO from those with malignant lesions.

Diagnostic accuracy of the constructive interference in steady state sequence alone for follow-up imaging of vestibular schwannomas

BACKGROUND AND PURPOSE

Vestibular schwannoma (VS) is a benign, slow-growing tumor, and radiologic monitoring is an acceptable alternative to surgery in small lesions and in elderly patients. MR imaging with contrast is the study of choice in the follow-up of these lesions. However, gadolinium-based contrast agents have side effects and should be used only when definitely indicated. The purpose of this study was to evaluate the diagnostic accuracy of the constructive interference in steady state (CISS) sequence used without postcontrast sequences for the follow-up imaging of VS.

MATERIALS AND METHODS

MR imaging examinations of 18 patients were retrospectively evaluated by 2 radiologists. VS masses were measured on both CISS and the postcontrast images by each observer. For each patient, the masses were also assessed qualitatively for possible progression between every consecutive study.

RESULTS

Fifty MR images of 18 patients were evaluated. Patients had 1-5 follow-up studies. The mean time interval between the consecutive studies was 23 months (6-55 months). The sensitivity, specificity, and accuracy of the CISS sequence for the detection of progression were 100%. There was good interobserver and intraobserver (CISS and postcontrast) correlation. The CISS sequence had, however, limited sensitivity for the detection of changes in the internal architecture.

CONCLUSIONS

Noncontrast CISS-only technique may be a viable alternative to routine contrast-enhanced sequences for the follow-up of overall lesion size in patients with VS; however, treatment-related changes internal to the tumor are less noticeable using the CISS sequence.

Complete labyrinthine aplasia: clinical and radiologic findings with review of the literature

BACKGROUND AND PURPOSE

Complete labyrinthine aplasia (CLA), also referred to as Michel aplasia, is a severe congenital anomaly of the inner ear, defined by the complete absence of inner ear structures. The purpose of this study was to document the imaging findings in a series of patients with CLA, with review of the literature, to better understand this anomaly.

MATERIALS AND METHODS

The CT and MR imaging findings of 9 patients (14 ears with CLA) were retrospectively evaluated. The audiologic tests and patient charts were also retrospectively reviewed.

RESULTS

CLA was bilateral in 5 and unilateral in 4 patients. The petrous bone was hypoplastic in all 14 ears, but the otic capsule was aplastic in only 5. The middle ear and mastoid volumes were decreased in most of the ears. The stapes was aplastic in 1 ear and was dysplastic in 5 ears. The internal acoustic canal was aplastic in 4 ears and markedly narrowed in 10 ears. The facial nerve canal showed a variety of anomalies and aberrant courses in 11/14 ears. The bony covering of the jugular bulb was defective in 9 ears. Tegmen tympani defects were seen in 3 patients, and there were several accompanying skull base and posterior fossa anomalies.

CONCLUSIONS

Although CLA is a rare developmental anomaly, its accurate diagnosis and its differential diagnosis from labyrinthine ossificans is crucial. Proper guidance of these patients for brain stem implantation in the critical period of brain development depends on the recognition of the characteristic imaging findings of CLA.

A double-blind, placebo-controlled, randomized clinical study of the effects of vardenafil on human nasal patency

BACKGROUND

Vardenafil, a selective phosphodiesterase 5 (PDE5) inhibitor, may affect nasal patency because of its adverse-effect profile. This double-blind, placebo-controlled, randomized clinical study sought to assess the effect of vardenafil on nasal patency in patients at a university hospital.

METHODS

Nasal patency was assessed using a visual analog score and by measuring the minimum cross-sectional areas (MCAs) and nasal cavity volumes with acoustic rhinometry in 14 subjects before and after administration of vardenafil. Measurements were repeated after administration of a local decongestant spray.

RESULTS

There was no statistically significant difference between the nasal cavity volumes, MCA, and visual analog scale (VAS) scores before and after the administration of placebo. However, there was a significant increase in the nasal cavity volumes, MCAs, and VAS scores after application of the local decongestant. A significant correlation was found between MCAs and VAS scores (r = 0.96; p < 0.001). After administration of vardenafil, there was a significant increase in the degree of subjective sense of nasal obstruction as measured by VAS scores. Total nasal volumes showed a significant decrease (p < 0.05). The congestion effect induced by the vardenafil was reversed after application of the local decongestant spray, and a significant increase in cross-sectional areas was noted. In the vardenafil group, a significant increase in MCA, total volume, and VAS scores was observed after application of the local decongestant (p < 0.05).

CONCLUSION

Objective and subjective nasal obstruction after administration of vardenafil was significantly higher in this study than in previously reported studies. The effect of congestion can be reversed by local decongestants. The role of PDE5 inhibitors in nasal physiology merits additional investigation.

Comparison of 45 degrees oblique reformats with axial reformats in CT evaluation of the vestibular aqueduct

BACKGROUND AND PURPOSE

Measurement of the vestibular aqueduct on CT scans of the temporal bone is important for the detection of large vestibular aqueduct syndrome; typically this is done in the axial plane. We sought to determine the usefulness of reformats performed in the 45 degrees oblique plane for evaluating the vestibular aqueduct. In addition, we provide reference measurements for the vestibular aqueduct in the 45 degrees oblique plane. MATERIALS AD METHODS: We selected 15 subjects referred for reasons other than sensorineural hearing loss, and without radiographic evidence of abnormality of the inner ear. Two neuroradiologists independently evaluated both axial and 45 degrees oblique images for ease in visualizing the vestibular aqueduct. Then, one of the readers (B.O.) performed reference measurements of the diameter at the mouth and midpoint of the aqueduct.

RESULTS

Combining the results of both observers, we judged 82% of vestibular aqueducts as well-defined or easily traced on 45 degrees oblique views, whereas we judged only 55% as well-defined or easily traced on axial views. The difference in the degrees of visualization between the 45 degrees oblique and axial reformats was significant for observer 1 (P =.022) and observer 2 (P =.001). Intraobserver agreement about the visibility of the aqueduct was higher on the 45 degrees oblique than the axial views: (kappa = 0.682, SE = 0.171) for 45 degrees oblique reformats; (kappa = 0.480, SE = 0.145) for axial reformats. On the 45 degrees oblique reformats, the mean external aperture dimension of the vestibular aqueduct was measured as 0.616 +/- 0.133 mm, and the postisthmic segment had a mean width of 0.482 +/- 0.099 mm.

CONCLUSIONS

The 45 degrees oblique plane gives a more reliable depiction of the vestibular aqueduct than the axial plane in CT evaluation of the temporal bone. This technique can be useful in cases of borderline enlargement of the vestibular aqueduct.

Diffusion-weighted cranial MR imaging findings in a patient with hemophagocytic syndrome

Hemophagocytic lymphohistiocytosis (HLH) is a rare disorder of the immune system that is associated with frequent involvement of the central nervous system (CNS). The MR imaging and CT findings of the CNS infiltration have been reported in the past; however, the diffusion-weighted imaging (DWI) findings have not been previously described. We present MR imaging findings in a case of secondary HLH with CNS involvement, with an emphasis on the DWI findings.

Delayed posttraumatic adrenal hematoma

Posttraumatic adrenal hemorrhage is a frequent finding after severe abdominal trauma and can have important clinical implications if it is bilateral. With the increased use of helical CT in the evaluation of trauma patients, posttraumatic adrenal hematoma is more frequently diagnosed. We present the CT findings of a unilateral posttraumatic adrenal hemorrhage where the diagnostic findings only appeared in the follow-up study. We think that mild enlargement of the adrenal gland in a trauma patient can be an early sign of an impending adrenal hemorrhage.