MRI Findings of COVID-19 Associated Acute Necrotizing Encephalopathy in Two Pediatric Patients: Case Report and Literature Review.

Acute necrotizing encephalopathy (ANE) is a rare immune-mediated complication of a viral infection commonly involving the bilateral thalamus and has been reported mainly in children. Here, we describe the MRI findings of coronavirus disease 2019 (COVID-19)-associated ANE in two pediatric patients, including a 7-year-old girl with fever and mental change, and a 6-year-old girl with fever and generalized seizures. Brain MRI revealed symmetrical T2 fluid attenuated inversion recovery high-signal intensity lesions in the bilateral thalamus with central hemorrhage. In one patient, the thalamic lesions showed a trilaminar pattern on the apparent diffusion coefficient map. This report emphasizes the importance of creating awareness regarding these findings in patients with COVID-19, particularly in children with severe neurological symptoms. Furthermore, it provides a literature review of several documented cases of COVID-19 presenting with bilateral thalamic hemorrhagic necrosis, suggesting a diagnosis of ANE.

Life Cycle Environmental Impact Assessment and Applicability of Synthetic Resin Formwork.

In this study, the environmental impacts of the production and field application of synthetic resin formwork were quantitatively compared to the Euro form. The noise test results showed an average of 107.3 dB (A) for the Euro form and 99.7 dB (A) for the synthetic resin formwork. Additionally, when the number of uses was considered, the CO2 emissions from the synthetic resin formwork were approximately 32% lower than the Euro form. Based on these results, it is expected that the use of synthetic resin formwork will reduce material production by half and reduce CO2 emissions compared to channel formwork.

Detection of Cerebrovascular Disease in a Child with Hutchinson-Gilford Progeria Syndrome Using MR Angiography: A Case Report.

Hutchinson-Gilford progeria syndrome (HGPS) is a rare, progressive, premature aging syndrome with early morbidity due to cardiovascular and cerebrovascular diseases. Clinical symptoms are very diverse, including non-specific symptoms such as growth retardation, scleroderma, alopecia, and osteoporosis, as well as hypertension and cardiovascular diseases that occur in childhood and adolescence due to accelerated vascular aging. In patients with HGPS, MR angiography is recommended for early diagnosis of asymptomatic stroke or vascular changes and to assess increased risk of cerebrovascular disease. We report the second domestic case of HGPS confirmed by genetic analysis in a 5-year-old child with typical clinical features, and the first English case report in Korea to present brain MR angiography findings.

Massive cerebral air embolism following percutaneous transhepatic biliary drainage: A case report.

RATIONALE: Cerebral air embolism from portal venous gas rarely occurs due to invasive procedures (e.g., endoscopic procedures, liver biopsy, or percutaneous transhepatic biliary drainage) that disrupt the gastrointestinal or hepatobiliary structures. Here, we report a rare case of fatal cerebral air embolism following a series of percutaneous transhepatic biliary drainage tube insertions. PATIENT CONCERNS: A 50-year-old woman with a history of cholecystectomy, liver wedge resection, and hepaticojejunostomy for gallbladder cancer presented with altered mental status 1 week after percutaneous transhepatic biliary drainage tube placement. DIAGNOSES: Extensive cerebral air embolism and acute cerebral infarction. INTERVENTIONS: Brain computed tomography and magnetic resonance imaging, hyperbaric oxygen therapy, medical therapy. OUTCOMES: Despite the use of hyperbaric oxygen therapy and medical treatment including vasopressors, the patient eventually died due to massive systemic air embolism. LESSONS: To date, there have been no reports of cerebral air embolism due to percutaneous transhepatic biliary drainage with pronounced radiologic images. We reviewed previously reported fatal cases associated with endoscopic hepatobiliary procedures and assessed the possible mechanisms and potential causes of air embolism.

Comparative Analysis on the Micropore and Microstructure Characteristics of Concrete under Insulated Formwork.

During concrete construction in winter, the concrete performance is generally improved by adding a chemical admixture or providing protection using tents and hot-air blowers. However, long-term strength or safety accidents may occur due to the installation and removal of the tents. This study considered insulated gang forms to improve formwork methods. In this regard, the microstructure and micropore characteristics of concrete were investigated experimentally to examine the insulated gang form effect on the physical and mechanical properties of concrete. The micropore characteristics were investigated through scanning electron microscopy. The results confirm that applying insulated gangs improves workability and safety without adding chemical admixture. Moreover, the application of insulated gang forms reduces the use of tents and hot-air blowers. Therefore, insulated gangs provide excellent initial quality to the concrete.

Magnetic Resonance Imaging Findings of Mumps Meningoencephalitis with Bilateral Hippocampal Lesions without Preceding Acute Parotitis: A Case Report.

Meningitis is a common central nervous system (CNS) complication of the mumps, a viral infection, but encephalitis and meningoencephalitis are less common in mumps. We describe magnetic resonance imaging findings of acute mumps meningoencephalitis in a 32-year-old male who showed bilateral hippocampal lesions without preceding parotitis. Although it is rare, hippocampal involvement should be considered a CNS complication of mumps infection.

Complete occlusion of the right middle cerebral artery associated with Mycoplasma pneumoniae pneumonia.

We report a case of a 5-year-old girl who developed left hemiparesis and left facial palsy, 6 days after the initiation of fever and respiratory symptoms due to pneumonia. Chest radiography, conducted upon admission, showed pneumonic infiltration and pleural effusion in the left lung field. Brain magnetic resonance imaging showed acute ischemic infarction in the right middle cerebral artery territory. Brain magnetic resonance angiography and transfemoral cerebral angiography revealed complete occlusion of the right middle cerebral artery. Mycoplasma pneumoniae infection was identified by a 4-fold increase in IgG antibodies to M. pneumoniae between acute and convalescent sera by enzyme-linked immunosorbent assay. Fibrinogen and D-dimer levels were elevated, while laboratory exams in order to identify other predisposing factors of pediatric stroke were all negative. This is the first reported pediatric case in English literature of a M. pneumoniae-associated cerebral infarction involving complete occlusion of the right middle cerebral artery.

Usefulness of Magnetic Resonance Sialography for the Evaluation of Radioactive Iodine-Induced Sialadenitis.

PURPOSE: Radioactive iodine (RAI) ablation therapy after thyroidectomy commonly leads to obstructive sialadenitis. Magnetic resonance (MR) sialography is an emerging imaging modality that enables morphological and functional changes to be evaluated. This study was conducted to investigate the usefulness of MR sialography for the evaluation of RAI sialadenitis. In addition, the authors evaluated the correlation of MR sialographic grading with symptom severity using a symptom questionnaire (SQ), and salivary gland (SG) functions as determined by salivary flow rates (SFRs) and salivary scintigraphy (SSG) parameters. METHODS: Eighteen patients with RAI sialadenitis who underwent MR sialography imaging were retrospectively enrolled. Subjective symptom scores were assessed and objective SG functions were evaluated. MR sialographic characteristics were analyzed and correlations between MR sialographic findings and clinicopathologic data, SQ, SFRs, and SSG parameters were investigated. RESULTS: MR sialography demonstrated diagnostic findings of ductal stenosis and sialectasis, non-visualized ducts, and glandular atrophy mainly involving parotid glands. A significant correlation was found between obstructive symptom scores and ductal stenosis and sialectasis grades (both p < 0.05). Degrees of ductal stenosis and sialectasis were significantly correlated with SSG excretory variables [time from stimulation to minimum count (t min) and maximum secretion; all p < 0.05]. Significant linear correlations were found between duct nonvisualization and uptake variables [uptake ratio (UR) and maximum accumulation (MA); both p < 0.05]. Glandular volumes were also significantly correlated with UR and MA (both p < 0.05). CONCLUSIONS: MR sialography images are useful for evaluating RAI sialadenitis, and its findings are in accordance with disease severity. An MR sialographic grading system is suggested to describe the severity of obstructive sialadenitis and SG dysfunction.

Computed tomography and magnetic resonance imaging findings of nasal cavity hemangiomas according to histological type.

OBJECTIVE: To compare computed tomography (CT) and magnetic resonance imaging (MRI) findings between two histological types of nasal hemangiomas (cavernous hemangioma and capillary or lobular capillary hemangioma). MATERIALS AND METHODS: CT (n = 20; six pre-contrast; 20 post-enhancement) and MRI (n = 7) images from 23 patients (16 men and seven women; mean age, 43 years; range, 13-73 years) with a pathologically diagnosed nasal cavity hemangioma (17 capillary and lobular capillary hemangiomas and six cavernous hemangiomas) were reviewed, focusing on lesion location, size, origin, contour, enhancement pattern, attenuation or signal intensity (SI), and bony changes. RESULTS: The 17 capillary and lobular hemangiomas averaged 13 mm (range, 4-37 mm) in size, and most (n = 13) were round. Fourteen capillary hemangiomas had marked or moderate early phase enhancement on CT, which dissipated during the delayed phase. Four capillary hemangiomas on MRI showed marked enhancement. Bony changes were usually not seen on CT or MRI (seen on five cases, 29.4%). Half of the lesions (2/4) had low SI on T1-weighted MRI images and heterogeneously high SI with signal voids on T2-weighted images. The six cavernous hemangiomas were larger than the capillary type (mean, 20.5 mm; range, 10-39 mm) and most had lobulating contours (n = 4), with characteristic enhancement patterns (three centripetal and three multifocal nodular), bony remodeling (n = 4, 66.7%), and mild to moderate heterogeneous enhancement during the early and delayed phases. CONCLUSION: CT and MRI findings are different between the two histological types of nasal hemangiomas, particularly in the enhancement pattern and size, which can assist in preoperative diagnosis and planning of surgical tumor excision.

Repeat Fine-Needle Aspiration Biopsy within a Short Interval Does Not Increase the Atypical Cytologic Results for Thyroid Nodules with Previously Nondiagnostic Results.

OBJECTIVE: The purpose of this study was to determine whether the recommended waiting period of 3 months is necessary for repeat fine-needle aspiration biopsy (FNAB). STUDY DESIGN: A retrospective review of 128 nodules from 126 patients with initial nondiagnostic (ND) results was performed for the period between January 2009 and December 2012. Demographic and clinical factors were recorded including age, sex, time interval between FNABs, and ultrasound (US) factors, i.e. nodule size, location, consistency, suspicious malignant findings and thyroiditis. The time interval was subdivided into

Brain stem hypoplasia associated with Cri-du-Chat syndrome.

Cri-du-Chat syndrome, also called the 5p-syndrome, is a rare genetic abnormality, and only few cases have been reported on its brain MRI findings. We describe the magnetic resonance imaging findings of a 1-year-old girl with Cri-du-Chat syndrome who showed brain stem hypoplasia, particularly in the pons, with normal cerebellum and diffuse hypoplasia of the cerebral hemispheres. We suggest that Cri-du-Chat syndrome chould be suspected in children with brain stem hypoplasia, particularly for those with high-pitched cries.

Automatic evaluation of cardiac hypertrophy using cardiothoracic area ratio in chest radiograph images.

To evaluate the cardiac hypertrophy from chest radiograph images, radiologists usually examine the cardiothoracic ratio (frequently called CTR) which is a standard diagnostic index. The CTR is computed by the maximum transverse diameter of the heart shadow divided by the maximum transverse diameter of right and left lung boundaries. In this paper, we present a method to evaluate the cardiac hypertrophy by comparing the area of heart with that of lung, instead of the cardiothoracic ratio to get more desirable diagnostic results. We introduce a new index, a cardiothoracic area ratio (CTAR), which is computed by dividing the area of heart region by the area of lung region of specific interest. We first segment a chest region of interest in a radiograph image and then automatically compute the traditional CTR and the CTAR to evaluate the cardiac hypertrophy. And finally, we provide the visual presentation of those ratios on the chest radiograph image. The experimental results using a set of radiograph images show that the proposed method can be used effectively for determining the cardiac hypertrophy in a real-time diagnostic environment. It provides the higher discrimination power than the CTR to identify hypertrophied hearts by recognizing the heart enlargement. It also can be used together with the traditional CTR as a complementary measure when it is difficult to determine abnormalities by the CTR, reducing the rate of wrong diagnosis.

Pseudoaneurysm of the popliteal artery mimicking tumorous condition.

Diagnosing pseudoaneurysms of the popliteal artery is usually straightforward in physical examinations and imaging findings. However, when a pseudoaneurysm shows a soft tissue mass with adjacent osseous change, it can mimic a bone tumor or a soft tissue sarcoma. We present a case of a 65-year-old man who had a pseudoaneurysm of the popliteal artery showing soft tissue mass and insinuating into the intramedullary cavity of the tibia. This presented case emphasizes the importance of considering pseudoaneurysms in the differential diagnosis of an apparent soft tissue mass with pressure erosion in adjacent bone.

Can necrotizing infectious fasciitis be differentiated from nonnecrotizing infectious fasciitis with MR imaging?

PURPOSE: To retrospectively evaluate whether magnetic resonance (MR) imaging findings can be used to differentiate necrotizing infectious fasciitis (NIF) from nonnecrotizing infectious fasciitis (non-NIF). MATERIALS AND METHODS: Institutional review board approval was obtained, but patient consent was not required for this retrospective review of records and images because patient anonymity was preserved. Thirty patients (seven with NIF, 23 with non-NIF) were included in the study. The following imaging findings were analyzed on fat-suppressed T2-weighted MR images: (a) signal intensity in the deep fascia (low, high, or mixed high and low), (b) thickness of abnormal signal intensity in the deep fascia (≥3 mm or <3 mm), (c) pattern of abnormal signal intensity in muscle (no abnormality, peripheral bandlike signal intensity, or patchy high signal intensity), (d) degree of deep fascia involvement (partial or extensive), and (e) degree of compartment involvement (fewer than three compartments or three or more compartments). On contrast material-enhanced fat-suppressed T1-weighted images, the contrast enhancement patterns of the abnormal deep fascia (no enhancement, enhancement, or enhancement with nonenhancing portion) and the muscle (no abnormality, peripheral bandlike signal intensity, or patchy high signal intensity) were evaluated. The presence of abscesses in the subcutaneous fat layer was evaluated with all sequences. RESULTS: The patients with NIF had a significantly greater frequency of (a) thick (≥3 mm) abnormal signal intensity on fat-suppressed T2-weighted images, (b) low signal intensity in the deep fascia on fat-suppressed T2-weighted images, (c) a focal or diffuse nonenhancing portion in the area of abnormal signal intensity in the deep fascia, (d) extensive involvement of the deep fascia, and (e) involvement of three or more compartments in one extremity (P < .05). CONCLUSION: MR imaging is potentially helpful for differentiating NIF from non-NIF. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101164/-/DC1.

Diffusion and perfusion characteristics of MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episode) in thirteen patients.

OBJECTIVE: We analyzed the diffusion and perfusion characteristics of acute MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episode) lesions in a large series to investigate the controversial changes of the apparent diffusion coefficient (ADC) that were reported in prior studies. MATERIALS AND METHODS: We analyzed 44 newly appearing lesions during 28 stroke-like episodes in 13 patients with MELAS. We performed a visual assessment of the MR images including the ADC and perfusion maps, comparison of the ADC between the normal and abnormal areas, comparison of % ADC between the 44 MELAS lesions and the 30 acute ischemic infarcts. In addition, the patterns of evolution on follow-up MR images were analyzed. RESULTS: Decreased, increased, and normal ADCs were noted in 16 (36%), 16 (36%), and 12 (27%) lesions, respectively. The mean % ADC was 102 ± 40.9% in the MELAS and 64 ± 17.8% in the acute vascular infarcts (p < 0.001), while perfusion imaging demonstrated hyper-perfusion in six acute MELAS lesions. On follow-up images, resolution, progression, and tissue loss were noted in 10, 4, and 17 lesions, respectively. CONCLUSION: The cytotoxic edema gradually evolves following an acute stroke-like episode in patients with MELAS, and this may overlap with hyper-perfusion and vasogenic edema. The edematous swelling may be reversible or it may evolve to encephalomalacia, suggesting irreversible damage.

Texture feature extraction based on a uniformity estimation method for local brightness and structure in chest CT images.

Texture feature is one of most important feature analysis methods in the computer-aided diagnosis (CAD) systems for disease diagnosis. In this paper, we propose a Uniformity Estimation Method (UEM) for local brightness and structure to detect the pathological change in the chest CT images. Based on the characteristics of the chest CT images, we extract texture features by proposing an extension of rotation invariant LBP (ELBP(riu4)) and the gradient orientation difference so as to represent a uniform pattern of the brightness and structure in the image. The utilization of the ELBP(riu4) and the gradient orientation difference allows us to extract rotation invariant texture features in multiple directions. Beyond this, we propose to employ the integral image technique to speed up the texture feature computation of the spatial gray level dependent method (SGLDM).

Granulocytic Sarcoma in the Head and Neck: CT and MR Imaging Findings.

OBJECTIVES: To evaluate characteristic computed tomography (CT) and magnetic resonance (MR) imaging findings of granulocytic sarcomas of the head and neck. METHODS: The CT (n=11) and MR (n=1) images obtained from 11 patients (7 males and 4 females; mean age, 23.5 yr; age range, 1 to 69 yr) with histologically-proven granulocytic sarcomas of the head and neck were retrospectively reviewed. Histological confirmation was done by bone marrow biopsy in 9 patients, and/or local biopsy in 4 patients. The imaging findings were analyzed with particular attention to location, size, shape, margin, bone destruction, internal architecture, pattern and degree of enhancement, and multiplicity of the lesions. RESULTS: The masses were most commonly located in the orbital cavity (n=8); other locations included lymph nodes (n=5) and palatine/pharyngeal/lingual tonsils (n=3). The mass sizes varied from a mean diameter of 1.3 to 5.8 cm (average, 2.6 cm). Multiple lesions were found in 6 patients. The shapes of the tumors were ovoid in 12 patients and irregular in 4 patients. Most lesions had poorly-defined margins (13/16) and invaded adjacent bony structures (5/16). On the pre-contrast CT images, the masses were iso- (5/8) or low-density (3/8) in comparison with muscle. The MRI, which was obtained in one patient in this study, showed that the mass was iso-signal intensity on T1-weighted images and iso-signal intensity on T2-weighted images compared to the gray matter of the brain. On the post-contrast CT images, there was homogenesous (n=12) or heterogeneous (n=4) enhancement, with mild (n=10), moderate (n=4), and marked (n=2) enhancement in the solid portions of the lesions. CONCLUSION: Although rare, granulocytic sarcomas arise in various locations in the head and neck area (most commonly in the orbit) in the form of well-demarcated, and mildly- and homogenously-enhancing masses with adjacent bony invasion.

MR imaging in a child with scurvy: a case report.

Scurvy is very rare disease in industrialized societies. Nevertheless, it still exists in higher risk groups including economically disadvantaged populations with poor nutrition, such as the elderly and chronic alcoholics. The incidence of scurvy in the pediatric population is very low. This study reports a case of scurvy in a 5-year-old girl with cerebral palsy and developmental delay based on MRI findings.

Acute pachymeningitis mimicking subdural hematoma in a patient with polyarteritis nodosa.

Pachymeningitis is a very rare neurologic manifestation of polyarteritis nodosa (PAN). This report describes a case of acute pachymeningitis that was, initially, misdiagnosed as subdural hematoma on the brain CT of a patient with PAN. A 45-year-old man, who had been diagnosed as having PAN 6 months previously, came back to the emergency room with complaints of sudden headache, nausea, vomiting, and diplopia for 3 days before his hospital admission. Initially, the noncontrast enhanced brain CT findings showed high densities in the bilateral tentorial and posterior parafalcial area, which suggested a small amount of subdural hematoma. However, the subsequent MRI findings revealed pachymeningitis of the bilateral tentoria and falx. He was treated with high-dose steroid and cyclophosphamide pulse therapy. Thereafter, his symptoms gradually resolved.

Mucinous adenocarcinoma arising from one retroperitoneal mature cystic teratoma in a postmenopausal woman.

Malignant degeneration of a retroperitoneal mature cystic teratoma to adenocarcinoma at postmenopausal age is extremely rare. A 72-year-old woman with mucinous adenocarcinoma arising from a retroperitoneal mature cystic teratoma is presented.