Imaging Features of Uncommon Entities That Manifest with Torsion.

Torsion is the twisting of an object along the axis, and various structures (organs and tumors) in the body can twist. Torsion causes initial lymphatic and venous outflow obstruction, leading to congestive edema, enlargement, venous hemorrhagic infarction, and surrounding edema. It can also cause subsequent arterial obstruction depending on the degree of torsion, leading to ischemia, infarction, necrosis, gangrene, and surrounding inflammation. Therefore, in several cases of torsion, immediate surgical intervention is required to improve blood flow and prevent serious complications. Clinical manifestations of torsion are often nonspecific and can affect individuals of varying ages and sex. Imaging plays an important role in the early diagnosis and management of torsion. Multiple imaging modalities, including US, radiography, CT, and MRI, are used to evaluate torsion, and each modality has its specific characteristics. The imaging findings reflect the pathophysiologic mechanism: a twisted pedicle (whirlpool sign), enlargement of the torsed structures, reduced blood flow, internal heterogeneity, and surrounding reactive changes. The whirlpool sign is a definitive characteristic of torsion. In some cases, despite poor internal enhancement, capsular enhancement is observed on contrast-enhanced CT and MR images and is considered to be associated with preserved capsular arterial flow or capsular neovascularization due to inflammation. Radiologists should be familiar with the pathophysiologic mechanisms, clinical characteristics, and imaging characteristics of torsion in various structures in the body. Since other articles about common organ torsions already exist, the authors of this article focus on the uncommon entities that manifest with torsion. ©RSNA, 2024.

Choroid plexus and pituitary gland hemochromatosis induced by transfusional iron overload: Two case reports.

Hemochromatosis is a primary or secondary pathological condition characterized by the deposition of excess iron in the body tissues, which can eventually lead to cellular damage and organ dysfunction. Although excess iron deposition in the central nervous system is rare, involvement of the choroid plexus, pituitary gland, cortical surfaces, and basal ganglia has been reported to date. This case report describes 2 cases of transfusion-induced hemochromatosis involving the choroid plexus and pituitary gland, which were diagnosed by magnetic resonance imaging (MRI). In both cases, gradient echo (GRE) sequences, such as T2 star-weighted image and susceptibility-weighted imaging demonstrated markedly low signal intensity in the choroid plexus. Furthermore, the pituitary gland showed low signal intensity on T2-weighted images in Patient 2. Because these low signal intensities were not seen prior to red blood cell transfusion, they were diagnosed with transfusion-induced hemochromatosis. Brain MRI with GRE sequences was useful in detecting iron deposition in the choroid plexus. Considering that iron deposition in the body tissues can lead to irreversible organ damage, MRI with GRE sequences should be considered for patients with suspected iron overload.

Pulmonary Vein Stenosis after Catheter Ablation for Atrial Fibrillation: An Early Diagnosis Using Unenhanced Computed Tomography.

Pulmonary vein stenosis (PVS) is a serious complication of catheter ablation (CA) for atrial fibrillation (AF). PVS generally occurs several months after CA and presents with non-specific symptoms and imaging findings. There have been reports of delayed diagnoses due to a misdiagnosis as infection, interstitial pneumonia, or organizing pneumonia. We introduced six cases of PVS after CA, all of which showed narrowing of the unilateral pulmonary vessels with or without lobar volume loss in the left lung on unenhanced computed tomography. We report these findings as important results indicating the possibility of PVS after CA for AF and contributing to the early diagnosis and management of PVS.

Optic pathway involvement in the posterior reversible encephalopathy syndrome: A case report and review of the literature.

Posterior reversible encephalopathy syndrome (PRES) is a clinico-radiological condition characterized by reversible vasogenic edema of the white matter and acute neurological symptoms. PRES typically affects the parieto-occipital regions but rarely affects the optic pathway. Herein, we describe a case of central-variant PRES in a 57-year-old man with abnormal signal intensities in the optic pathway on magnetic resonance imaging (MRI). The patient underwent hemodialysis, initiated diuretics and antihypertensive medications, and the abnormal signal intensities of the brainstem and optic pathway on MRI improved. Although rare, PRES can affect the optic pathway, thus suggesting the possibility of fragility of the optic pathway itself to hyperperfusion.

Magnetic resonance imaging findings of sclerosing microcystic adenocarcinoma: A case report and review of the literature.

Sclerosing microcystic adenocarcinoma (SMA) is a rare malignant tumor of the salivary glands that closely resembles cutaneous microcystic adnexal carcinoma (MAC). It was newly listed in the 5th edition of the WHO classification of head and neck tumors. This report describes the case of a 61-year-old woman who presented with masses on the floor of the mouth. The masses showed low signal intensity on T2-weighted images (T2WI) and with low apparent diffusion coefficient (ADC) values. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) revealed a plateau or persistence after rapid initial enhancement. Histopathologically, the tumors comprised small infiltrating strands of cells that formed small ducts and cysts embedded in thick fibrous stroma, consistent with SMA. Low signal intensity on T2WI with a low ADC value and a plateau or persistence after rapid initial enhancement on DCE-MRI reflect the fibrous and cellular components of the tumor and can be considered characteristic MRI findings of SMA.

Antimutagenic, anti-inflammatory, and antioxidative activities of the juice of Vitis ficifolia var. Ganebu, a woody vine in the grape family, known as Ryukyu-ganebu in Japan.

BACKGROUND: Mutation, inflammation, and oxidative damage including lipid-peroxidation are factors involved in the development of cancer. We investigated the antimutagenic, in vivo and in vitro anti-inflammatory, and antioxidative effects of the juice of Vitis ficifolia var. ganebu (known as Ryukyu-ganebu in Japan) harvested in Kuchinoshima island (hereafter, the juice is referred to as ganebu-K) in comparison with the juice of Vitis coignetiae (crimson glory vine, known as yamabudo in Japan; hereafter, the juice is referred to as yamabudo) which we found antimutagenic and anti-inflammatory effects. RESULTS: Ganebu-K inhibited the mutagenic activity of several carcinogens, MeIQx, IQ, Trp-P-2(NHOH), and MNNG, model compounds of tumor initiation. Using S. typhimurium YG7108, a strain lacking O6-methylguanine DNA methyltransferases, ganebu-K showed no significant inhibition of the mutagenicity of MNNG. Thus, DNA repair of O6-methylguanine produced by MNNG might be an antimutagenic target of the components in ganebu-K. Topical application of ganebu-K to the dorsal sides of mice resulted in potent suppression of acute edema induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). Ganebu-K, but not yamabudo, exhibited significant inhibition of the induction of prostaglandin E2 (PGE2) induced by TPA. Components contained in ganebu-K, but not in yamabudo, might be responsible for the inhibition of the induction of PGE2. Ganebu-K inhibited in vivo lipid peroxidation and decreased the level of glutamic oxaloacetic transaminase induced by CCL4 treatment. CONCLUSIONS: These results suggest that the active components in ganebu-K juice are not the same as those in yamabudo, and the components in ganebu-K are attractive candidates as chemopreventive agents.

Chemopreventive effects and anti-tumorigenic mechanisms of 2,6-dimethoxy-1,4-benzoquinone, a constituent of Vitis coignetiae Pulliat (crimson glory vine, known as yamabudo in Japan), toward 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis in A/J mice.

Previously, we isolated and identified anti-mutagenic and anti-inflammatory components from Vitis coignetiae (crimson glory vine, known as yamabudo in Japan) as 2,6-dimethoxy-1,4-benzoquinone (DBQ), fertaric acid and caftaric acid. We also reported that the oral intake of a partially purified fraction from yamabudo juice (yamabudo-fr) or DBQ affords significant protection against two-stage skin carcinogenesis in mice. In this study, we found that oral intake of yamabudo-fr or DBQ affords significant protection against a tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced mouse model of lung tumorigenesis. Furthermore, we investigated the anti-tumorigenic mechanisms of yamabudo juice and DBQ. NNK is known to be a DNA-methylating and alkylating agent; thus, we investigated the anti-tumorigenic mechanisms of yamabudo juice and DBQ in relation to DNA methylation. Pretreatment with yamabudo-fr or DBQ dose-dependently decreased formation of O6-methylguanine and N7-methylguanine in DNA of the A549 human lung epithelial-like cell line treated with a methylating agent, 1-methyl-3-nitro-1-nitrosoguanidine. Yamabudo juice and DBQ inhibited the mutagenicity of NNK in the Ames test using Salmonella typhimurium TA1535 but not S. typhimurium YG7108, an alkylguanine DNA alkyltransferase-deficient strain (same as TA1535 but Δadast::Kmr, Δogtst::Cmr). Yamabudo juice and DBQ might accelerate the repair of DNA damage caused by NNK and reduce DNA damage to cells. We also investigated the effects of yamabudo juice and DBQ on signaling pathways in A549 cells. With or without epidermal growth factor stimulation, phosphorylation of Erk1/2, Akt and Stat3 in A549 cells was significantly decreased in the presence of yamabudo juice or DBQ, indicating that yamabudo juice and DBQ suppressed PI3K/AKT, MAPK/ERK and JAK/STAT3 signaling pathways. These results suggest that both initiation and growth/progression steps in carcinogenesis, especially anti-oxidant effects, stimulation of repair of alkyl DNA adducts and suppressed growth signaling pathways are potential anti-tumorigenic targets of yamabudo juice and DBQ in NNK-induced lung tumorigenesis.

2,6-Dimethoxy-1,4-benzoquinone, isolation and identification of anti-carcinogenic, anti-mutagenic and anti-inflammatory component from the juice of Vitis coignetiae.

Previously we demonstrated the anti-tumorigenic, anti-mutagenic and anti-inflammatory effects of the juice of Vitis coignetiae (yamabudo), and identified caftaric acid as an anti-mutagenic component from the juice. In the present study, we investigated the isolation of anti-inflammatory components in yamabudo juice supposing that the anti-inflammatory components in yamabudo are also responsible for the anti-tumorigenic activity. The suppressing effect on nitric oxide production in mouse leukemic monocyte with LPS was used as a separation marker. Three components comprising 2,6-dimethoxy-1,4-benzoquinone (DBQ), fertaric acid and caftaric acid were isolated and identified from the juice of V. coignetiae as anti-inflammatory ingredients. Inhibitory effects were found of DBQ on the mutagenicity of dimethylbenzo[a]anthracene, aflatoxin B1, 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) and amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in the Ames test. Topical application of DBA significantly inhibited TPA-induced edema of mouse ears. The anti-tumorigenic effect of DBQ on the promotion and initiation stages of mouse skin tumorigenesis was investigated, and topical administration of DBQ on the promotion stage significantly decreased tumor development in mice skin. DBQ is a potential candidate for the chemopreventive effect of V. coignetiae.

Spontaneous intracranial hypotension complicated by cerebral venous thrombosis.

Spontaneous intracranial hypotension (SIH) is a well-known cause of orthostatic headache. Although subdural fluid collection is a usual complication of SIH, SIH as a risk factor for cerebral venous thrombosis (CVT) is not well-known. There are several mechanisms that could contribute to the development of CVT in SIH. Herein, we report a case of a 33-year-old woman with SIH complicated by CVT. She was treated with anticoagulation but did not receive a blood patch for the SIH, because there was resolution of orthostatic headache with bed rest and sufficient hydration. Follow-up magnetic resonance imaging showed resolution of the findings of SIH and CVT. Patients with SIH should be closely observed for any change in the headache pattern, which might suggest the development of CVT.