Search

Both pilocytic astrocytoma (PA) and hemangioblastoma (HB) are common primary neoplasms of the posterior fossa with similar radiological manifestations. This study was conducted to evaluate the role of Radiomics in differentiating these two conditions in adults. After a retrospective search of our institutional imaging archive, adult patients with a known diagnosis of PA or HB were included. We reviewed each patient's most recent preoperative brain magnetic resonance imaging (MRI). The solid enhancing nodule of each lesion on post-contrast T1 sequence was manually segmented. Multiple Radiomics features were then extracted from each nodule using the Pyradiomics library. Subsequently, the most predictive features were identified by feature selection models. Following this, different machine learning (ML) models were constructed based on these selected features to classify lesions as PA or HB. Finally, we evaluated the performance of each model by leave-one-out cross-validation. With inclusion and exclusion criteria, 34 enhancing PA nodules and 39 HB nodules were selected. A total of 115 features were extracted from each enhancing nodule. Twelve characteristics were detected as most predictive of histopathological diagnosis. Among various ML models, the neural network had the best performance in differentiating these two conditions with an AUC of 0.9 and an accuracy of 82%. In this retrospective study, Radiomics MRI techniques demonstrated high performance in distinguishing adult posterior fossa PA from HB. Future development of Radiomics models may advance presurgical diagnosis of these two conditions when added to routine clinical practice and thus improve patient management. • Differentiation between hemangioblastoma and pilocytic Astrocytoma in the "adult" is challenging on conventional medical imaging. • However, an accurate preoperative diagnosis is crucial and can significantly alter patient management and surgical technique. • Our preliminary results regarding the application of Radiomics appear promising for this task, and we got an AUC of 0.9 without using any clinical information such as the patient's age. [ABSTRACT FROM AUTHOR]

Encephalitis is a relatively challenging rare condition caused by a diverse group of etiologies. Brainstem encephalitis/Rhombencephalitis (BE), which affects the cerebellum, pons, and medulla, is even less common and more challenging for diagnosis and treatment. At this time, there is scattered data about BE in the literature, mainly in the form of case reports and case series. In this manuscript, the imaging presentation of BE is reviewed with the help of case examples. Many imaging presentations are not pathognomonic for BE; however, in many cases, clinical presentation, the spatial distribution of lesions, and other associated radiological lesions can provide the radiologists and clinician the clues to an accurate diagnosis. [ABSTRACT FROM AUTHOR]

Critical illness–associated cerebral microbleed (CICM) is a relatively rare and newly described condition. It can occur in critically ill ICU patients and can be secondary to many underlying etiologies. CICM is associated with high mortality and permanent neurologic deficits in surviving patients. Distribution of cerebral microhemorrhages in neuroimaging findings is critical for accurate diagnosis of this condition. Here, we present an ICU admitted patient with sickle cell disease crisis and CICM and will discuss their clinically and radiologically distinct phenomenon followed by a review of current literature. • CICM is a relatively rare and newly described form of cerebral microhemorrhage. • CICM can occur in sickle cell disease patients. • CICM mainly involves the gray-white matter junction of the brain. [ABSTRACT FROM AUTHOR]

A rare but important complication related to otherwise uneventful brain and spine surgery is becoming more recognized and more frequently reported in the medical literature. This has been variably labeled as pseudohypoxic brain swelling or postoperative hypotension-associated venous congestion. This poorly understood condition occurs in the setting of surgical intervention and is thought to be related to cerebrospinal fluid leak or evacuation, decreased intracranial pressure, and subsequent development of deep venous congestion affecting the basal ganglia, thalami, and cerebellum. Clinically, patients may have global neurologic deficit and outcomes range from full recovery to vegetative state or death. The imaging correlate includes atypical edema, infarction, or hemorrhage and can overlap the appearance of diffuse hypoxic injury, for which this condition can be mistaken both clinically and radiologically. Although this deep brain tissue edema can be associated with other signs of cerebrospinal fluid hypotension such as dural thickening, brain sagging, and cerebellar herniation, it can be isolated, making the diagnosis challenging. We present 2 cases of unexpected clinical deterioration occurring in patients with otherwise uncomplicated neurosurgery, 1 with craniotomy and the other with lumbar spine intervention. Both patients exhibit similar appearing edema in the deep gray structures on postoperative magnetic resonance imaging scans. In addition to reviewing the prior literature and imaging findings, we evaluate the imaging findings to determine if there are unique features or signatures that might allow differentiation of PHBS from hypoxic-ischemic encephalopathy. The lentiform rim sign can be helpful for differentiation of pseudohypoxic brain swelling versus hypoxic-ischemic encephalopathy. [ABSTRACT FROM AUTHOR]

Rationale and Objectives: Regarding the most recent ischemic stroke treatment guideline, perfusion imaging has been recommended up to 24 hours after initial symptoms of brain infarction. Patients with a significant amount of salvageable peri-infarct ischemia and no contraindications benefit from delayed thrombolysis and intra-arterial thrombectomy. This approach causes increasingly more CT perfusion to be done in the subacute phase of ischemic stroke. CT perfusion findings in this "subacute phase" are slightly different from "hyper-acute" ischemic stroke. The interpreting radiologist must be confident in reporting the CT perfusion study in an urgent setting since these studies are under the umbrella of "code-stroke" and should be read in minutes. In addition, results of the CT perfusion have a critical effect on the patient's outcome and misinterpretation can be fatal in that underestimation of the salvageable ischemia excludes the patient from potential effective treatment. Underestimation of infarct volume may cause unnecessary thrombolysis/thrombectomy and potentially fatal intracranial hemorrhage.Materials and Methods: In this review, we are trying to explain the basic concept of "code-stroke" CT perfusion, typical findings, and pitfalls in a practical way. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: It has been reported that a novel type of magnetic resonance imaging (MRI) scan called echo planar magnetic resonance spectroscopic imaging (EP-MRSI) may show antidepressant effects. We examined whether the two routine diagnostic protocols of MRI [T1 and echo planar diffusion weighted imaging (EPI-DWI)], have antidepressant-like effects in an animal model of depression. Methods: The effects of standard EPI-DWI and T1 MRI on immobility, swimming and climbing times in the modified forced swimming test (FST) in mice were examined. After exposure to the first session of modified forced swimming test, we randomly divided the mice into four groups. The first group (T1 MRI group, n =21) received a 15-minute stimulation of T1 sequence. The second group (EPI-DWI MRI group, n =21) received a 15-minute stimulation of EPI-DWI protocol. The third group (sham group, n =21) spent 15 min in a tunnel similar to the MRI gantry in terms of size, temperature and light intensity and received recorded sounds from a normal session of EPI-DWI with similar duration and intensity. The fourth group acted as controls (n =21).The second session of the modified FST was conducted twelve hours later. The mean of immobility, swimming and climbing times in this session were compared to the control group. Results: T1 weighted and EPI-DWI MRI groups showed a reduction in immobility time compared to the control group (P value<0.002, P value<0.017 respectively). This effect is comparable to that seen in the FST after the administration of antidepressant agents. The climbing time in the group subjected to EPI-DWI MRI was longer than the control group (P value<0.035). Previous studies showed similar effects after the administration of antidepressant drugs affecting the catecholamine systems. The swimming time in the T1 MRI group was significantly longer than the control group (P value<0.037). Previous studies showed qualitatively similar effect to that of anti-depressant drugs affecting the serotoninergic systems. The swimming, climbing and immobility times in the sham and control groups showed no significant difference. Conclusions: Our findings raise the possibility that MRI-based stimulation may have antidepressant-like effects in mice. This is likely to be through different mechanisms in T1 weighted and EPI-DWI protocols. However the possible biological basis of this effect is not yet understood and we would advocate further studies of MRI-based stimulation effects on transmitters in the different organs in the body specially the brain. [Copyright &y& Elsevier]

Abstract: The purpose of this study is to clarify the prevalence, spectrum of associated tumors and the diagnostic value of the linear meningeal thickening and enhancement adjacent to a peripherally located cranial mass “dural tail sign”(DTS) in contrast enhanced magnetic resonance imaging (MRI). In this prospective descriptive cross-sectional study conducted from 2002 to 2005, 110 patients with imaging-proven intracranial lesions and no history of previous intracranial surgery were referred to the neurosurgery clinic of our hospital for surgical resection. All underwent imaging with a 1.5T MR system with and without contrast injection. Twelve patients were excluded from our study and finally 98 patients were evaluated for the presence of “dural tail sign”. Twenty-two of 98 patients (22.44%) with intracranial masses exhibited the “dural tail sign” (18 meningiomas, 2 pituitary adenomas, 1 primary cerebral lymphoma and 1 fungal brain abscess). Fifty-eight percent of the patients with biopsy-proven meningioma were observed to show “dural tail sign”. In conclusion, we found the “dural tail sign” to have a sensitivity of 58.6% and specificity of 94.02% in diagnosis of meningioma. [Copyright &y& Elsevier]

Abstract: A rare adult case of absent azygos vein associated with polysplenia syndrome who was admitted due to pulmonary emboli is presented, image findings are described and embryological bases of venous abnormalities and its association with coagulopathy is discussed via reviewing literatures. [Copyright &y& Elsevier]

COVID-19 infection is less common in children (with higher fetal hemoglobin levels). In our preliminary study, we also observed a low prevalence and fatality of COVID-19 in countries with high rate of hemoglobinopathy carries. Given these two facts, the hemoglobin structure can play a role in the physiopathology of COVID-19 disease. Several drugs are known to increase fetal hemoglobin in adults. Adding these drugs to COVID-19 clinical trials may improve the patients' outcomes. [ABSTRACT FROM AUTHOR]

Angiosarcomas are rare malignant tumors of endothelial origin. Nearly one half of all angiosarcomas occur in the head and neck. Temporal bone angiosarcomas are extremely uncommon. We present a case of temporal bone angiosarcoma and a review of the relevant data. We present the case of a 20-year-old man with a painful right postauricular mass after a closed head injury. Radiologic studies demonstrated a large right osteolytic and heterogeneously enhancing mass. The patient underwent right transpetrosal craniectomy for resection. Histologic studies confirmed high-grade sarcoma. Immunohistochemical staining demonstrated a uniformly positive ERG endothelial marker, CD31 staining with cytoplasmic and membranous patterns of immunopositivity, positive nuclear staining for FLI-1, positive cytoplasmic and membranous staining for CD99 and STAT6, and negative smooth muscle actin stains in the neoplastic cells. Ki-67 staining showed ∼94% positivity in the neoplastic cell nuclei. Postoperative follow-up imaging studies demonstrated evidence of metastatic right cervical lymphadenopathy. Angiosarcoma of the temporal bone is extremely uncommon. In the present case report, we explored a relationship between trauma and angiosarcoma of the temporal bone. We reviewed the reported data regarding the pathogenesis, diagnosis, treatment, radiologic findings, and histologic characteristics of angiosarcoma of the temporal bone. [ABSTRACT FROM AUTHOR]

Abstract: Objective: The exact nature of the “dural tail sign” (thickening of the dura adjacent to the tumour in contrast enhanced T1-MRI imaging) is still not clearly established. In this study we tried to verify the histological appearance of the “dural tail sign” and probable correlation between different MRI findings and dural tail histology. Material and methods: In this study, 129 patients with intracranial lesions underwent MRI imaging with 1.5T scanner. The “dural tail sign” was defined using Goldsher et al. criteria. Size and pattern of enhancement of the tumour and adjacent dura was noted in MRI and in the pathologic samples, dural tail and the dura beneath the tumour was assessed. Results: In 30 cases, “dural tail sign” was evident on MRI, dural tail noted in 17 of these cases in histological samples (12 meningiomas, 3 pituitary adenomas and 2 schwannomas). All of them had vessel dilatation, 6 showed tumoural invasion, 4 demonstrated intravascular growth of the lesion and 1 showed inflammation of the dura. Conclusion: In our study MRI findings failed to predict tumoural invasion of the dural tail in histologic samples and because of frequent presence of tumour nests in it, the dura matter should be resected as widely as possible. [Copyright &y& Elsevier]