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.

Unveiling the mille-feuille sign: a key to diagnosing ovarian carcinosarcoma in addition to ovarian metastasis from colorectal carcinoma on MRI.

PURPOSE: To clarify the diagnostic utility and formation of the Mille-feuille sign for ovarian carcinosarcoma (OCS) on MRI, and to evaluate the other MRI findings and serum markers compared to ovarian metastases from colorectal carcinoma (OMCRC). METHOD: Three blinded radiologists retrospectively reviewed MR images of 12 patients with OCS, 18 with OMCRC, and 40 with primary ovarian carcinoma (POC) identified by the electronic database of radiology reports. The interobserver agreement was analyzed using Fleiss' kappa test. Their MRI characteristics and tumor markers were compared using Fisher's exact test and Mann-Whitney's U test. Receiver operating characteristic curve analyses were used to determine the cutoff points for the ADC value. This study was approved by the institutional ethics committee. RESULTS: Interobserver agreement analysis was moderate or higher for all MRI characteristics. The frequency of Mille-feuille sign was comparable for both OCS and OMCRC groups, and predominantly higher than that of the POC group (p < 0.001, p < 0.001), respectively. Pathologically, the Mille-feuille sign in OCS reflected alternating layers of tumor cells with stroma and necrosis or intraluminal necrotic debris. Compared to OMCRC, intratumoral hemorrhage (p = 0.02), margin irregularity (p = 0.048), unilateral adnexal mass (p = 0.02), and low ADC values (p < 0.01) were more frequently observed and serum CEA levels was significantly lower (p = 0.007) in the OCS group. Under setting of the cutoff value of ADC at 0.871 × 10-3mm2/s, the discriminative ability for OCS showed 66.7% sensitivity, 94.4% specificity, and 81.0% accuracy, respectively. CONCLUSIONS: The Mille-feuille sign was seen in both OCS and OMCRC. MR findings of intratumoral hemorrhage, margin irregularity, unilateral adnexal mass, low ADC values, and low serum CEA levels can be useful in differentiating OCS from OMCRC.

Magnetic resonance imaging features of complete androgen insensitivity syndrome in comparison to Mayer-Rokitansky-Küster-Hauser syndrome.

PURPOSE: Complete androgen insensitivity syndrome (CAIS) and Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS) share common clinical features such as female phenotype, vaginal hypoplasia, and primary amenorrhea. Magnetic resonance imaging (MRI) is performed to investigate the cause of primary amenorrhea. However, the MRI features are also similar in both disorders. They are ultimately diagnosed by chromosome testing, but there is a possibility of misdiagnosis if chromosome testing is not performed. This study aimed to identify MRI features that are useful for differentiating CAIS from MRKHS. METHOD: This multicenter retrospective study included 12 patients with CAIS and 19 patients with MRKHS. Three radiologists blindly evaluated the following features: (1) detection of vagina, (2) detection of nodular and cystic structures in the lateral pelvis; undescended testicles and paratesticular cysts in CAIS and rudimentary uteri and ovaries in MRKHS, (3) their location, (4) number of cysts in the cystic structures, and (5) signal intensity on diffusion-weighted images (DWI) and apparent diffusion coefficient (ADC) values of the nodular structures. Statistical comparisons were performed using Mann-Whitney U and Fisher's exact tests. RESULTS: Compared with MRKHS, the CAIS group showed significantly detectable vagina, more ventrally located nodular and cystic structures, fewer cysts within the cystic structures, and nodular structures with higher signal intensity on DWI and lower ADC values. CONCLUSIONS: MRI features of detectable vagina, location of nodular and cystic structures, number of cysts within the cystic structures, signal intensity on DWI and ADC values of the nodular structures were useful in differentiating CAIS from MRKHS.

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.

A case of papilledema in Camurati-Engelmann disease treated effectively with prednisolone.

Camurati-Engelmann disease (CED) causes bone pain, muscle weakness, and cranial nerve symptoms due to abnormal thickening of the long bones of the limbs and the cortex of the skull. The pathophysiology of CED is a gain-of-function variant of transforming growth factor beta 1 (TGFB1). The ophthalmological symptoms of CED are usually caused by increased intracranial pressure and optic canal stenosis. Here, we report the case of a patient in whom prednisolone was effective against papilledema caused by CED. In this case, when papilledema was observed in both fundi, the patient showed increased bone pain, fever, and elevated CRP and ALP levels. Brain magnetic resonance imaging (MRI) revealed a high short tau inversion recovery (STIR) signal in both optic nerves, suggesting edematous changes. Prednisolone ameliorated bone pain, fever, and papilledema, resulting in a slight improvement of the visual function of the right eye. Our results suggest that prednisolone may be effective in treating ophthalmologic symptoms in addition to bone pain in patients with CED.

Massive true thymic hyperplasia with osseous metaplasia.

True thymic hyperplasia is defined as an increase in both the size and weight of the gland, while maintaining a normal microscopic architecture. Massive true thymic hyperplasia is a rare type of hyperplasia that compresses adjacent structures and causes various symptoms. Limited reports address the imaging findings of massive true thymic hyperplasia. Herein, we report a case of massive true thymic hyperplasia in a 3-year-old girl with no remarkable medical history. Contrast-enhanced CT revealed an anterior mediastinal mass with a bilobed configuration containing punctate and linear calcifications in curvilinear septa, which corresponded to lamellar bone deposits in the interlobular septa. To our knowledge, this is the first report of massive true thymic hyperplasia with osseous metaplasia. We also discuss the imaging features and etiology of massive true thymic hyperplasia with osseous metaplasia.

Computed tomography findings, temporal course, and clinical relevance of subpleural pulmonary interstitial emphysema in patients with pneumomediastinum.

BACKGROUND: Subpleural pulmonary interstitial emphysema is defined as the air in the subpleural portion of the lung, and the clinical relevance is not well understood. PURPOSE: to evaluate the frequency, temporal course, risk factors, and clinical significance of subpleural pulmonary interstitial emphysema (PIE) in patients with pneumomediastinum resulting from ruptured alveoli and other causes. MATERIAL AND METHODS: This was a retrospective study of 130 patients with pneumomediastinum on CT between January 2009 and December 2019 at 2 hospitals. Patients were divided into 3 groups as follows: spontaneous pneumomediastinum (n = 101), pneumomediastinum due to blunt trauma (n = 16), and pneumomediastinum due to another known cause (n = 13). The frequencies of radiographic features (subpleural PIE, peribronchovascular PIE, pneumothorax, pulmonary fibrosis, and emphysematous changes) between the 3 groups were compared by the χ2 or Kruskal-Wallis test. Odds ratios were calculated to evaluate candidate risk factors for subpleural and peribronchovascular PIE. RESULTS: Subpleural PIE was observed in 0%, 15.8%, and 31.3% of patients with pneumomediastinum due to another cause, spontaneous mediastinum, and blunt trauma, respectively. In most patients, subpleural PIE resolved spontaneously (85.7% within 8 days). Two patients with pulmonary fibrosis showed recurrent subpleural PIE on follow-up. Young age showed increased risk for subpleural PIE (odds ratio [OR] 0.9, 95% confidence interval [CI] 0-0.99). CONCLUSION: Subpleural PIE was only detected in patients with pneumomediastinum due to ruptured alveoli and resolved spontaneously and rapidly. Subpleural PIE may be one route the air from ruptured alveoli to the mediastinum.

Hydrogel Glucose Sensor with In Vivo Stable Fluorescence Intensity Relying on Antioxidant Enzymes for Continuous Glucose Monitoring.

Hydrogel glucose sensors with boronic acid-based fluorescence intensity theoretically hold promise to improve in vivo continuous glucose monitoring (CGM) by facilitating long-lasting accuracy. However, these sensors generally degrade after implantation and the fluorescence intensity decreases immediately over time. Herein, we describe a hydrogel glucose sensor with in vivo stability based on boronic acid-based fluorescence intensity, integrating two antioxidant enzymes, superoxide dismutase (SOD), and catalase. These protected the arylboronic acid from being degraded by hydrogen peroxide in vitro and preserved the boronic acid-based fluorescence intensity of the hydrogel glucose sensors in rats for 28 days. These antioxidant enzymes also allowed the hydrogel glucose sensor attached to a homemade semi-implantable CGM device to trace blood glucose concentrations in rats for 5 h with the accuracy required for clinical settings. Hydrogel glucose sensors with boronic acid-based fluorescence intensity containing SOD and catalase could comprise a new strategy for in vivo CGM.

Thromboaspiration for Iatrogenic Thrombotic Occlusion of the Superior Mesenteric Artery during Endovascular Treatment of Pancreaticoduodenal Artery Aneurysm and Celiac Artery Occlusion.

Herein, we present a case of superior mesenteric artery (SMA) thrombus as a complication of stent placement for celiac stenosis and coil packing of a pancreaticoduodenal artery aneurysm. The SMA thrombus was likely caused by thromboembolism from the guiding sheath in the SMA without a continuous heparin flush. It was promptly treated with aspiration thrombectomy, and there was no mesenteric ischemia. To avoid thromboembolic complications, periprocedural prophylactic antithrombotic therapy should also have been performed because a complex procedure involving the pull-through technique was performed.

Symptomatic jugular venous reflux with dilatation of the superior ophthalmic vein mimicking cavernous dural arteriovenous fistula.

We report a case of symptomatic jugular venous reflux (JVR) with dilatation of left superior ophthalmic vein (SOV), mimicking cavernous dural arteriovenous fistula (AVF). Severe JVR was caused by an AVFfor hemodialysis access and the narrowing of the left brachiocephalic vein. In-flow signals were found from the left internal jugular vein to left SOV on magnetic resonance angiography, and T1-weighted image and T2-weighted images demonstrated flow voids in bilateral sigmoid sinuses and confluence of sinuses due to rapid retrograde venous flow. We would like to emphasize that the presence of in-flow signals/flow voids in the venous sinuses may be the key imaging clues to distinguish JVR with dilatation of the SOV from cDAVF.