Characteristic MR Imaging Findings Research Articles

Characteristic MR Imaging Findings of Cerebral Air Embolism Infarcts: A Case Series.

Infarcts from cerebral air embolism are rare events with potentially catastrophic clinical consequences. The imaging features of cerebral air embolism are not well-defined in the literature. We report a novel constellation of MR imaging findings of cerebral arterial air emboli-induced infarcts in a series of 6 patients. Awareness of the more distinguishing MR imaging patterns of cerebral air embolism may help establish this diagnosis and facilitate implementation of timely treatment.

MR Imaging Findings of Carcinoma Ex Pleomorphic Adenoma Related to Extracapsular Invasion and Prognosis.

MR imaging can reflect the pathologic progression of carcinoma ex pleomorphic adenoma (CXPA). This study aimed to identify the imaging findings related to extracapsular invasion of CXPA. Additionally, the pathologic background of these findings was investigated. This retrospective study included 37 patients with histologically confirmed CXPA. Three radiologists independently evaluated whether the CXPA showed the following characteristic MR imaging findings: border, capsule, the corona sign on fat-saturated T2WI and contrast-enhanced fat-saturated T1WI, and the black ring sign. The corona sign appeared larger on fat-saturated and/or contrast-enhanced fat-saturated T1WI than on T1WI. The black ring sign was defined as an intratumoral nodule with a thick low-intensity rim on T2WI. Interreader agreement of the visual assessment was performed using κ analysis, and MR imaging and histopathologic findings were also correlated. Kaplan-Meier survival and the log-rank test were used to estimate the 3-year disease-free survival. MR imaging findings, especially peritumoral findings, showed a significant difference between invasive and noninvasive CXPA. The reliability was poor for the border and capsule. In contrast, it was good for the corona sign on fat-saturated and contrast-enhanced fat-saturated T1WI and the black ring sign. Pathologically, the corona sign reflected the invasiveness of the tumor and inflammatory cells, while the black ring sign reflected hyalinization or fibrosis. The corona sign also showed a significant difference in the 3-year disease-free survival. MR imaging findings, including the corona and black ring signs, reliably differentiated invasive and noninvasive CXPA. The corona sign can be used as a prognostic factor for CXPA.

Characteristic MR Imaging Findings of the Temporomandibular Joint in Diabetes Mellitus: Focus on Abnormal Bone Marrow Signal of the Mandibular Condyle and Lymph Node Swelling in the Parotid Glands

Characteristic MR Imaging Findings of the Temporomandibular Joint in Diabetes Mellitus: Focus on Abnormal Bone Marrow Signal of the Mandibular Condyle and Lymph Node Swelling in the Parotid Glands

MRI Findings of Immune Checkpoint Inhibitor-Induced Hypophysitis: Possible Association with Fibrosis.

Hypophysitis is one of the well-known adverse effects of immune checkpoint inhibitors. Immune checkpoint inhibitor-induced hypophysitis frequently causes irreversible hypopituitarism, which requires long-term hormone replacement. Despite the high frequency and clinical significance, characteristic MR imaging findings of immune checkpoint inhibitor-induced hypophysitis have not been established. In the present study, we aimed to review and extract the MR imaging features of immune checkpoint inhibitor-induced hypophysitis. This retrospective international multicenter study comprised 20 patients with melanoma who were being treated with immune checkpoint inhibitors and clinically diagnosed with immune checkpoint inhibitor-induced hypophysitis. Three radiologists evaluated the following MR imaging findings: enlargement of the pituitary gland and stalk; homogeneity of enhancement of the pituitary gland; presence/absence of a well-defined poorly enhanced area and, if present, its location, shape, and signal intensity in T2WI; and enhancement pattern in contrast-enhanced dynamic MR imaging. Clinical symptoms and hormone levels were also recorded. Enlargement of the pituitary gland and stalk was observed in 12 and 20 patients, respectively. Nineteen patients showed poorly enhanced lesions (geographic hypoenhancing lesions) in the anterior lobe, and 11 of these lesions showed hypointensity on T2WI. Thyrotropin deficiency and corticotropin deficiency were observed in 19/20 and 12/17 patients, respectively, which persisted in 12/19 and 10/12 patients, respectively, throughout the study period. Pituitary geographic hypoenhancing lesions in the anterior lobe of the pituitary gland are characteristic and frequent MR imaging findings of immune checkpoint inhibitor-induced hypophysitis. They reflect fibrosis and are useful in distinguishing immune checkpoint inhibitor-induced hypophysitis from other types of hypophysitis/tumors.

Characteristic MR Imaging Findings of the Neonatal Brain in RASopathies.

Neuroimaging features in neonates with RASopathies are rarely reported, and to date, there are no neuroimaging studies conducted in this population. Our aim was to investigate the occurrence of supratentorial and posterior fossa abnormalities on brain MRIs of neonates with a RASopathy. An observational case-control study of neonates with a confirmed RASopathy was conducted. The presence of an intraventricular and/or parenchymal hemorrhage and punctate white matter lesions and assessments of the splenium of the corpus callosum, gyrification of the cortical gray matter, and enlargement of the extracerebral space were noted. The vermis height, transverse cerebellar diameter, cranial base angle, tentorial angle, and infratentorial angle were measured. We reviewed 48 brain MR studies performed at 3 academic centers in 3 countries between 2009 and 2017. Sixteen of these infants had a genetically confirmed RASopathy (group 1), and 32 healthy infants were enrolled as the control group (group 2). An increased rate of white matter lesions, extracerebral space enlargement, simplification of the cortical gyrification, and white matter abnormalities were seen in group 1 (P < .001, for each). The vermis height of patients was significantly lower, and tentorial and infratentorial angles were significantly higher in group 1 (P = .01, P < .001, and P = .001, respectively). Neonates with a RASopathy had characteristic structural and acquired abnormalities in the cortical gray matter, white matter, corpus callosum, cerebellum, and posterior fossa. This study provides novel neuroimaging findings on supratentorial and posterior fossa abnormalities in neonates with a RASopathy.

CT and MRI imaging features of carcinoma of the duodenal papilla

In this article, we reviewed the CT/MRI imaging features of carcinoma of the duodenal papilla in 15 cases. The characteristic CT and MR imaging findings of duodenal papillary carcinoma included mass in the descending part of the duodenum, the mass and duodenum wall showed atargetsign ordiamond ringsign; a ring-enhancing lesions around the distal end of the common bile duct/pancreatic duct, and thickening of the wall of the second portion of the duodenum near the papilla. The use of MPR MDCT images and MRI coronal images are very useful to show these imaging features as an aid in early diagnosis of carcinoma of the duodenal papilla. Key words: Duodenal papillary carcinoma; Computed tomography (CT); Magnetic resonance imaging (MRI)

Characteristic CT and MR imaging findings of cerebral paragonimiasis

The early diagnosis of cerebral paragonimiasis (CP) is essential for a good prognosis. We seek to provide references for early diagnosis by analyzing the imaging characteristics of cerebral paragonimiasis. Images of 27patients with CP (22males and 5females; median age 20.3years; range: 4 to 47 years) were retrospectively evaluated. All patients underwent head computed tomography (CT) scans; 22 patients underwent conventional magnetic resonance imaging (MRI) sequences, including contrast-enhanced MRI for 20patients and diffusion-weighted-imaging (DWI) for 1 patient. The diagnosis was confirmed based on a positive antibody test using enzyme-linked immunosorbent assay (ELISA) for paragonimiasis in the serum. The most common imaging findings of CP were isodense or hypodense lesions combined with extensive hypodense areas of perilesional edema on CT scans and a large mass composed of multiple ring-shaped lesions with surrounding edema on MRI images. The conglomeration of multiple ring-shaped lesions (n=11patients), "tunnel signs" (n=12patients) and worm-eaten signs (n=5patients) were characteristic of most CP images. In 14patients, contrast-enhanced MRI showed varying degrees of contrast enhancement combined with adjacent meningeal enhancement (n=10). A large mass comprising multiple ring-shaped lesions of different sizes, "tunnel signs" and worm-eaten signs with surrounding edema are the most characteristic features of CP. Extensive invasions of the adjacent meninges and ventricular wall (19patients), multiple intracerebral lesions, bilateral hemispheric involvement, and lesion migration are other noteworthy imaging characteristics.

Recent advances of study on hereditary diffuse leukoencephalopathy with spheroids

Hereditary diffuse leukoencephalopathy with neuroaxonal spheroids (HDLS) is a rare autosomal dominant leukoencephalopathy disease, and colony stimulating factor 1 receptor (CSF1R) is the only gene in which mutations are known to cause HDLS. HDLS should be suspected in individuals with progressive neurological decline, characteristic MR imaging findings, and positive family history. This article reviews recent advance in imaging findings, clinical manifestations, genetic counseling and management in HDLS.

Imaging of the cavernous sinus lesions

This educational paper reviews the normal anatomy of the cavernous sinus (CS) and the imaging findings of common and uncommon lesions of this region. CS lesions may arise from different components of the CS or from adjacent structures and spaces. They can be classified as tumoral, inflammatory/infectious, vascular and congenital. Tumoral lesions include benign (meningiomas, pituitary adenomas, schwannomas) and malignant neoplasms (chondrosarcomas, chordomas, nasopharyngeal carcinomas, leukemia, metastases). Inflammatory/infectious conditions comprise: Tolosa Hunt, abscess, Lemierre syndrome and thrombophlebitis. Vascular lesions include: hemangiomas, carotido-cavernous fistula, aneurysms, arteriovenous malformations. Congenital conditions include the epidermoid cyst, dermoid cyst and fatty deposits. Although imaging features of non-vascular CS diseases are most often non-specific, careful analysis of the adjacent structures suggests the correct diagnosis. In vascular pathology, characteristic MR imaging findings are observed.

Morning Glory Disc Anomaly: Characteristic MR Imaging Findings

Establishing the diagnosis of morning glory disc anomaly is crucial to appropriate patient treatment. Although typically made clinically, the diagnosis is not always straightforward, especially in circumstances where physical examination is limited. The goal of this study was to define the spectrum and frequency of orbital findings in a series of patients with funduscopically-confirmed morning glory disc anomaly by using MR imaging. MR imaging demonstrated 3 findings in all patients: 1) funnel-shaped morphologic pattern of the posterior optic disc with elevation of the adjacent retinal surface; 2) abnormal tissue associated with the distal intraorbital segment of the ipsilateral optic nerve, with effacement of the regional subarachnoid spaces; and 3) discontinuity of the uveoscleral coat. These findings were not observed in any of the unaffected globes of the study patients. In summary, these consistent and characteristic findings of morning glory disc anomaly should allow for accurate differentiation from other ocular anomalies and have the potential to guide appropriate management of this patient population.

Cervicofacial tissue infarction in patients with acute invasive fungal sinusitis: prevalence and characteristic MR imaging findings

Tissue infarction is known as one of the characteristic features of invasive fungal sinusitis (IFS). The purpose of this study was to investigate the prevalence and characteristic MR imaging findings of cervicofacial tissue infarction (CFTI) associated with acute IFS. We retrospectively reviewed MR images in 23 patients with histologically or microbiologically proven acute IFS. CFTI was defined as an area of lack of enhancement in and around the sinonasal tract on contrast-enhanced T1-weighted images. We divided CFTI into two groups, i.e., intrasinonasal and extrasinonasal. Particular attention was paid to the location of extrasinonasal CFTI and the signal intensity of CFTI on T1- and T2-weighted images. The presence of bone destruction on CT scans was also recorded. CFTI was found in 17 (74%) of 23 patients. All of these 17 patients had intrasinonasal CFTI, and 13 patients also had extrasinonasal CFTI. All 13 patients with extrasinonasal CFTI died of disease directly related to IFS. Various locations were involved in the 13 patients with extrasinonasal CFTI, including the orbit (n = 8), infratemporal fossa (n = 7), intracranial cavity (n = 3), and oral cavity and/or facial soft tissue (n = 4). Various signal intensities were noted at the area of CFTI on T1- and T2-weighted images. Bone destruction was found on CT scans in only 3 of 17 patients with CFTI. CFTI with preservation of the bony wall of the involved sinonasal tract may be a characteristic MR imaging finding of acute IFS. The mortality is very high once the lesion extends beyond the sinonasal tract.

CT and MR Imaging Findings of Sinonasal Schwannoma: A Review of 12 Cases

Schwannomas are benign tumors that are rarely found in the sinonasal cavity, and the purpose of this study was to characterize the CT and MR imaging findings of 12 patients with surgically proved sinonasal schwannomas. Assessed features include location, margin, shape, size, internal architecture, pattern and degree of enhancement, and associated bony wall changes. The characteristic CT and MR imaging findings of sinonasal schwannoma include a well-defined soft-tissue mass, most frequently occurring in the nasal cavity and ethmoid sinus with pressure remodeling of the adjacent bony wall. The tumors were isoattenuating on CT and predominantly isointense on both T1- and T2-weighted MR images, compared with the brain stem. Mild contrast enhancement on CT and strong enhancement on MR images were also demonstrated in most of the tumors, and cystic or hemorrhagic changes were noted in 2 cases.

Characteristic MR and CT imaging findings of hepatobiliary paragonimiasis and their pathologic correlations

Hepatobiliary paragonimiasis (HP) is not commonly encountered and may be confused with hepatobiliary tumors; however, computed tomography (CT) and magnetic resonance imaging (MRI) features of HP allow this entity to be distinguished from other diseases. To present the CT and MRI findings in patients with HP and to describe some specific imaging findings along with their pathological correlations. Imaging and clinical findings of 21 patients (9 boys/men and 12 girls/women; age range 3-67 years; mean age 40 years) who were diagnosed with HP were retrospectively evaluated. Among these patients, 16 underwent CT examination only, two had MR examination only, and three underwent both CT and MR. All patients underwent surgery, and the HP diagnosis was confirmed by the surgical and histopathologic results. Chronic abdominal pain or back pain was reported by 14 patients, severe abdominal pain with acute onset was reported by one patient, and six patients were asymptomatic and were discovered incidentally. Peripheral eosinophilia was present in 14 patients (14/21, 66.7%), and abnormal liver function tests were found in 16 patients (16/21, 76.2%). Of the 19 patients who underwent CT imaging, 17 patients showed multiple mixed hypodense lesions or multiple cysts with inlaying septation with separate irregular rims or circular enhancement on post-contrast CT images. Tunnel-shaped microabscesses and necrotic cavities were found in the lesions of 12 of those 17 patients. The other two patients showed smaller cystic masses. MRI showed faveolate T1 hypointense and T2 hyperintense areas in the liver parenchyma with rim or peripheral enhancement. Nodular or circular hyperintense materials were found scattered in the lesions on T1-weighted imaging. CT and MRI can reveal the radiological-pathological features of HP. Together with laboratory findings, MRI and CT findings may provide diagnostic clues, especially in endemic areas, that are very important for the selection of treatment methods.

Relationships between edema degree and clinical and biochemical parameters in posterior reversible encephalopathy syndrome: a preliminary study

The objective of the study was to investigate the associations between the degree of edema with the clinical and biochemical parameters such as serum lactate dehydrogenase (LDH), albumin (ALB) in posterior reversible encephalopathy syndrome (PRES) patients. Forty-nine patients with typical clinical symptoms and characteristic MR imaging findings of PRES were included in this study. Lactate dehydrogenase and ALB were analyzed with the immunoluminometric assays. Fluid-attenuated inversion recovery images were used to evaluate the distribution of the extent or severity of vasogenic edema by two observers. Correlation analysis between the scores of brain edema and the blood pressures, clinical conditions and biochemical parameters was performed. No significant difference of brain edema score was found between patients with eclampsia, chronic renal failure and other clinical condition (P > 0.05). Both mean arterial pressures and LDH level were moderately correlated with the scores of brain edema distribution (Spearman's ρ test, r = 0.405 and 0.497, respectively, P < 0.01). Serum ALB level was not correlated with the scores of brain edema distribution (P > 0.05). Larger and more diffuse lesions may be predicted by higher LDH level and blood pressure. The overall severity of the systemic process might be predicted by the degree of edema expression in PRES.

Association of degree and type of edema in posterior reversible encephalopathy syndrome with serum lactate dehydrogenase level: Initial experience

PurposePosterior reversible encephalopathy syndrome (PRES) is a clinicoradiologic entity characterized by headache, blurred vision and seizures with typical parieto-occipital predominantly vasogenic edema, occasionally with cytotoxic edema. The association between the degree and type of edema in PRES with biochemical parameter, especially serum lactate dehydrogenase, has not been determined. Material and methodsThirty-five patients with typical clinical symptoms and characteristic MR imaging findings of PRES were included in this study. The extent of brain edema was graded on the anatomical distribution by 2 observers blinded to patients’ clinical record, as well as the type of brain edema determined on DWI and ADC map. The levels of biochemical parameters were correlated with the degree of edema and compared between different types of edema. ResultsSerum LDH concentrations between patients with cytotoxic edema and with vasogenic components were not statistically different (NWU test, U=93.0, Z=1.818, P=0.069). Only serum lactate dehydrogenase (LDH) concentration was significantly correlated with the score of brain edema distribution (Spearman's rho correlation, r=0.721, P=0.00). No relationship was found between other biochemical parameters and the degree and type of brain edema. ConclusionIncreased serum LDH level, which plays an essential role in endothelial injury, may be a potential risk factor for the development of edema in PRES.

Kimura Disease: CT and MR Imaging Findings

KD is a rare chronic inflammatory disorder of unknown etiology. The purpose of this study was to evaluate the CT and MR imaging findings of KD in the head and neck. We retrospectively reviewed the CT (n = 21) and MR (n = 9) images obtained in 28 patients (24 males and 4 females; mean age, 32 years; age range, 10-62 years) with histologically proved KD in the head and neck. In these 28 patients, CT and MR images demonstrated a total of 52 non-nodal lesions, 1-8 cm in greatest diameter, in the head and neck. The lesions were unilateral in 11 patients and bilateral in 17 patients. Eleven patients had a solitary lesion, and 17 patients had 2-4 lesions. The parotid and/or periparotid area was the most frequent location, with 36 lesions in 23 patients. The margin of the lesions was well-defined in 1 and ill-defined in 51 cases. Compared with the adjacent muscle, the MR signal intensity of all lesions was iso- to slightly hyperintense on T1-weighted images and hyperintense on T2-weighted images. Most of the lesions demonstrated mild or moderate enhancement on postcontrast CT scans and moderate or marked enhancement on postcontrast MR images. MR images also showed tubular signal-intensity voids in 7 of 13 lesions. Associated lymphadenopathy was demonstrated in 23 patients, usually bilaterally. Multiple ill-defined enhancing masses within and around the parotid gland with associated regional lymphadenopathy are characteristic CT and MR imaging findings of KD in the head and neck.

Characteristic MR imaging findings and surgical treatment of cavernous hemangiomas in cavernous sinus

Objective To analyze the imaging character and surgical therapy of cavernous hemangiomas in cavernous sinus ( CSHs ).Method From 2001 to 2008,13 patients with CSHs were surgically treated in our department.The diameters of CSHs varied from 3.5 cm to 6.0 cm.Results All the patients were operated on with no mortality.Complete tumor removal was achieved in 9 cases,partial tumor removal in 3 cases,and biopsy in 1 case.Cranial nerve Ⅲ was preserved in 8 cases and cranial nerves V2,V3 in 9 cases.In the other cases,cranial nerves in cavernous sinus were sacrificed unavoidably.Conclusions CSHs can be diagnosed preoperatively according to MRI and can be removed successfully by experienced surgeons who are familiar with operative approaches and microsurgical technique.However,great efforts should be made to decrease postoperative cranial nerve deficits. Key words: Cavernous sinus ; Hemangioma,cavernous,central nervous system ; Microsurgery ;

MR findings of synovial disease in children and young adults: Part 1

Synovial diseases in children can be classified into normal structures as potential sources of pathology (synovial folds: plicae, infrapatellar fat pad clefts); noninfectious synovial proliferation (juvenile idiopathic arthritis, hemophilic arthropathy, lipoma arborescens, synovial osteochondromatosis, pigmented villonodular synovitis, reactive synovitis), and infectious synovial proliferation, deposition disease, vascular malformations, malignancy (including metastasis) and intra-articular/periarticular cysts and cyst-like structures (ganglia). Familiarity with characteristic MR imaging findings of synovial diseases in children and young adults will enable a more confident diagnosis for earlier intervention and directed therapy. The first part of this paper will cover potential pathology of normal synovial structures as well as noninfectious synovial proliferation.

Subconjunctival Fat Prolapse and Dermolipoma of the Orbit: Differentiation on CT and MR Imaging

Subconjunctival fat prolapse and dermolipoma of the orbit are unfamiliar to radiologists and yet should be differentiated because their treatments are different. The purpose of this study was to investigate the CT and MR imaging findings that distinguish these 2 conditions. Between 1995 and 2009, we found 33 patients (27 men, 6 women; mean age, 63 years) with surgically proved subconjunctival fat prolapse and 27 patients (3 males, 24 females; mean age, 17 years) with dermolipoma in our hospital. Among them, 8 patients with subconjunctival fat prolapse and 6 patients with dermolipoma underwent CT and/or MR imaging examinations. We retrospectively reviewed CT scans and MR images in these patients. In all of the 8 patients with subconjunctival fat prolapse, CT and MR images demonstrated the herniated fat at the superotemporal epibulbar area, continuous with the intraconal fat, extending forward between the lateral wall of the globe medially and the lateral rectus muscle and the lacrimal gland laterally, either bilaterally (n = 7) or unilaterally (n = 1). In contrast, all 6 patients with dermolipoma had a unilateral, crescent- (n = 5), or triangle-shaped (n = 1) fatty mass at the temporal or superotemporal epibulbar area, which lay on the lateral wall of the globe, anterior to the insertion of the lateral rectus muscle and medial to the lacrimal gland, without connection to the intraconal fat. The characteristic CT and MR imaging findings may help easily differentiate subconjunctival fat prolapse and dermolipoma, both of which usually present as an epibulbar fatty mass in the lateral canthal area.

Characteristic MR Imaging Findings of Neurocutaneous Melanosis

Neurocutaneous melanosis is a type of phakomatosis characterised by dermal, leptomeningeal and parenchymal melanocytic naevi. Here we describe a case of a 13-year-old boy with dermal and brain parenchymal melanosis without any leptomeningeal melanosis.