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.

Diagnostic imaging and histopathologic features of rounded atelectasis in four cats and one dog: A descriptive case series study.

In humans, rounded atelectasis is defined as focal lung collapse that radiologically appears as a round mass-like lesion in the periphery of the lung. In general, human patients with rounded atelectasis have a history of pleural effusion and abnormal pleura and characteristic CT findings help to distinguish rounded atelectasis from pulmonary neoplasia without the need for invasive surgical biopsy. This retrospective multi-center case series describes rounded atelectasis in four cats and one dog. Chylothorax was seen in four patients and an eosinophilic and lymphoplasmacytic effusion was seen in one patient. All patients had solitary or multifocal subpleural pulmonary masses (26 masses total in 5 patients) with diffuse, multifocal, or focal visceral and parietal pleural thickening. All the masses but one were broad-based towards the visceral pleura. Masses were most common in the ventral or lateral aspect of the lungs. Indistinctness at the hilar aspect of the lesion was seen in all masses; a "comet tail" sign was seen in 14 of 26 masses. On postcontrast images, the lesions were homogeneously enhanced in 24 of 26 masses and heterogeneous in two of 26 masses. Other findings include ground glass opacities (n = 5), parenchymal bands (n = 4), mild to moderate lymphadenopathy (n = 4), and compensatory hyperinflation of the lung lobes not affected by atelectasis (n = 2). Histopathology of four cases revealed atelectasis with fixed pleural folds, chronic pleuritis, and mild to moderate pleural fibrosis. Awareness of rounded atelectasis in veterinary species will enable inclusion of a benign etiology into the differential diagnosis for subpleural masses in cases with pleural abnormalities.

Location of embolization affects patency after coil embolization for pulmonary arteriovenous malformations: importance of time-resolved magnetic resonance angiography for diagnosis of patency.

OBJECTIVES: This study aimed to assess the diagnostic accuracy of computed tomography (CT) and time-resolved magnetic resonance angiography (TR-MRA) for patency after coil embolization of pulmonary arteriovenous malformations (PAVMs) and identify factors affecting patency. METHODS: Data from the records of 205 patients with 378 untreated PAVMs were retrospectively analyzed. Differences in proportional reduction of the sac or draining vein on CT between occluded and patent PAVMs were examined, and receiver operating characteristic analysis was performed to assess the accuracy of CT using digital subtraction angiography (DSA) as the definitive diagnostic modality. The accuracy of TR-MRA was also assessed in comparison to DSA. Potential factors affecting patency, including sex, age, number of PAVMs, location of PAVMs, type of PAVM, and location of embolization, were evaluated. RESULTS: The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of CT were 82%, 81%, 77%, 85%, and 82%, respectively, when the reduction rate threshold was set to 55%, which led to the highest diagnostic accuracy. The sensitivity, specificity, PPV, NPV, and accuracy of TR-MRA were 89%, 95%, 89%, 95%, and 93%, respectively. On both univariable and multivariable analyses, embolization of the distal position to the last normal branch of the pulmonary artery was a factor that significantly affected the prevention of patency. CONCLUSIONS: TR-MRA appears to be an appropriate method for follow-up examinations due to its high accuracy for the diagnosis of patency after coil embolization of PAVMs. The location of embolization is a factor affecting patency. KEY POINTS: • Diagnosis of patency after coil embolization for pulmonary arteriovenous malformations (PAVMs) is important because a patent PAVM can lead to neurologic complications. • The diagnostic accuracies of CT with a cutoff value of 55% and TR-MRA were 82% and 93%, respectively. • The positioning of the coils relative to the sac and the last normal branch of the artery was significant for preventing PAVM patency.

Preoperative intravascular ultrasonographic evaluation of leiomyosarcoma of the inferior vena cava: A case report.

Leiomyosarcoma of the inferior vena cava is a rare malignant tumor originating from smooth muscle cells of the vascular media. Its preoperative diagnosis by conventional noninvasive examinations such as abdominal ultrasonography, X-ray computed tomography, and magnetic resonance imaging, may be difficult because of their nonspecific findings. We present the case of a 72-year-old woman with leiomyosarcoma of the inferior vena cava diagnosed by intravascular ultrasonography.

[Comparison of Influence of Susceptibility Artifact due to Metallic Embolic Material in MRA Image].

PURPOSE: To identify the influence of susceptibility artifact caused by commonly used trans-catheter embolic devices for vascular lesions in the body on the images of various magnetic resonance angiography (MRA) techniques as an aid to patient screening after endovascular embolization. MATERIALS AND METHODS: We constructed vascular phantoms in which three embolic materials; platinum coil, Inconel coil, and vascular plug, were placed. Each phantom was imaged with three types of MRA techniques as follows: ultra-short echo time magnetic resonance imaging (UTE), three-dimensional fast advanced spin echo (3D-FASE), time-resolved contrast MRA with key hole technique (Key hole). For each embolic material, four reviewers compared the visual capabilities of the vessel lumen and surrounding area of each MRA technique by using a four-point visual scoring system. The quantitative values of susceptibility artifacts generated from each embolic material were compared between each MRA technique. RESULTS: For all MRA techniques, the platinum coil showed the highest visual score (median=four-point) among all the embolic materials (p<0.05). In the platinum coil, the MR signal in the coil was clearly depicted in UTE. For all MRA technique, the quantitative values of the susceptibility artifacts were the lowest in platinum coil among all the embolic materials (p<0.05). CONCLUSION: UTE is less susceptible to susceptibility artifact of embolic materials.

Perihepatic caudate lobe haematoma originating from a pancreatic pseudoaneurysm: a diagnostic dilemma.

Despite advances in diagnostic imaging and interventional techniques, pancreatic pseudoaneurysms remain a life-threatening complication of pancreatitis. Presentation varies among patients and may include intra-abdominal, retroperitoneal, or gastrointestinal bleeding and bleeding into the pancreatic or common bile duct. We present a unique case of a 74-year-old man with a history of heavy alcohol consumption who presented with a haematoma surrounding the caudate lobe of the liver. Initially, alcoholic cirrhosis and a ruptured hepatocellular carcinoma were suspected. Therefore, transarterial embolization (TAE) of the caudate branch of the hepatic artery was performed. However, 3 months later, the patient experienced abdominal pain with a lesser sac haematoma and a seemingly interconnected pancreatic cyst. One month later, a pseudoaneurysm appeared in the pancreatic cyst. TAE was successfully performed for the pseudoaneurysm, and the patient showed no signs of recurrence during the 1-year follow-up.

Diversity, composition and potential roles of sedimentary microbial communities in different coastal substrates around subtropical Okinawa Island, Japan.

BACKGROUND: Marine benthic prokaryotic communities play crucial roles in material recycling within coastal environments, including coral reefs. Coastal sedimentary microbiomes are particularly important as potential reservoirs of symbiotic, beneficial, and pathogenic bacteria in coral reef environments, and therefore presumably play a core role in local ecosystem functioning. However, there is a lack of studies comparing different environments with multiple sites on the island scale, particularly studies focusing on prokaryotic communities, as previous investigations have focused mainly on a single site or on specific environmental conditions. In our study, we collected coastal sediments from seven sites around Okinawa Island, Japan, including three different benthic types; sandy bottoms, seagrass meadows, and hard substratum with living scleractinian corals. We then used metabarcoding to identify prokaryotic compositions and estimate enzymes encoded by genes to infer their functions. RESULTS: The results showed that the three substrata had significantly different prokaryotic compositions. Seagrass meadow sites exhibited significantly higher prokaryotic alpha-diversity compared to sandy bottom sites. ANCOM analysis revealed that multiple bacterial orders were differentially abundant within each substratum. At coral reef sites, putative disease- and thermal stress-related opportunistic bacteria such as Rhodobacterales, Verrucomicrobiales, and Cytophagales were comparatively abundant, while seagrass meadow sites abundantly harbored Desulfobacterales, Steroidobacterales and Chromatiales, which are common bacterial orders in seagrass meadows. According to our gene-coded enzyme analyses the numbers of differentially abundant enzymes were highest in coral reef sites. Notably, superoxide dismutase, an important enzyme for anti-oxidative stress in coral tissue, was abundant at coral sites. Our results provide a list of prokaryotes to look into in each substrate, and further emphasize the importance of considering the microbiome, especially when focusing on environmental conservation. CONCLUSION: Our findings prove that prokaryotic metabarcoding is capable of capturing compositional differences and the diversity of microbial communities in three different environments. Furthermore, several taxa were suggested to be differentially more abundant in specific environments, and gene-coded enzymic compositions also showed possible differences in ecological functions. Further study, in combination with field observations and temporal sampling, is key to achieving a better understanding of the interactions between the local microbiome and the surrounding benthic community.

Asymmetric genetic population structures at the range edges of a mangrove whelk.

Many marine species are distributed across incredibly wide geographical ranges spanning thousands of kilometers often due to movement along prevailing ocean currents. However, data are lacking on genetic connectivity among populations of such widespread species within or among ecoregions, possibly due to the lack of appropriate datasets. In this study, we investigated the genetic structure of populations of the mangrove whelk, Terebralia palustris, using mitochondrial cytochrome oxidase subunit I (COI) sequences. Sequences generated for this study from Okinawa, Japan, were compared to samples from the coast of East Africa analyzed in a previous study. Interestingly, despite considerable distance separating them, the African and Japanese populations share major haplotypes and do not show clear genetic differentiation. At lower latitudes, core African populations exhibited higher genetic diversity than either the more southerly African and Japanese populations. Genetic ß-diversity revealed that the northern edge population in Japan has a greater proportion of ßSNE (the nestedness-resultant component), indicating contemporary migration, whereas the southern edge population in Africa is characterized by a predominant ßSIM (the turnover component), suggesting historical demography. A potential cause of this dissimilarity could be due to the strong Kuroshio Current along the Ryukyu Islands, which may promote larval dispersal. These differing patterns suggest that there may be divergent responses to future climate change at the population level at the periphery of the range of T. palustris.

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.

Idiopathic myointimal hyperplasia of mesenteric veins: radiological evaluation using CT angiography.

A 44-year-old man presented with a chief complaint of constipation. Initial contrast-enhanced CT showed extensive bowel wall thickening, mainly in the left colon, with a thin cord-like inferior mesenteric vein (IMV), in contrast to ectatic mesenteric venous branches, suggesting bowel ischaemia owing to venous stasis. One month later, at the time of symptom exacerbation, CT angiography showed a cord-like IMV and ectatic mesenteric venous branches with early enhancement, suggesting the presence of an arteriovenous fistula (AVF). Owing to the progression of bowel ischaemia and necrosis with peritonitis, emergency surgery was performed. Surgical specimens showed focal myointimal hyperplasia of the proximal mesenteric veins in both ischaemic and non-ischaemic lesions of the resected colon, thus leading to the diagnosis of idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) when combined with the clinical and imaging findings. IMHMV is a bowel ischaemic disease caused by non-thrombotic venous obstruction that requires bowel resection and has been suggested to be associated with AVF. Cord-like IMV and AVF in the mesentery are important CT findings that characterize IMHMV. CT angiography is useful in diagnosing IMHMV.

Involvement of the parasympathetic nervous system in the initiation of regeneration of pancreatic ß-cells.

The mechanism that initiates regeneration of pancreatic ß-cells is not clear at present. The vagal nerve is implicated in the regulation of gastrointestinal functions, glucose metabolism and proliferation of pancreatic ß-cells under physiological conditions. To elucidate the triggering mechanism of the regeneration of pancreatic ß-cells, we examined the involvement of the vagal nerve. To this end, we employed a rat pancreatic duct ligation (DL) model, in which profound ß-cell neogenesis and ß-cell proliferation were observed within a week. We administered atropine to block the vagal nerve. Administration of atropine inhibited proliferation of ß-cells in both islets and islet-like cell clusters (ICC), without affecting ductal cell proliferation in the ligated pancreas. The numbers of PDX-1 and MafB-positive cells in or attaching to the ducts were significantly reduced by atropine. MafB/glucagon and MafB/insulin double-positive cells were also decreased by atropine. Finally, atropine reduced the number of MafA-positive ductal cells, all of which were positive for insulin, by 50% on day 5. These results strongly suggest that the vagal nerve is involved in ß-cell proliferation, induction of endocrine progenitors and neogenesis of α- and ß-cells.

Lymphoscintigraphy with single-photon emission computerized tomography/computed tomography for evaluating lymphatic leakage following pelvic and para-aortic lymphadenectomy.

Lymphatic ascites following pelvic and para-aortic lymphadenectomy is a well-known complication. Surgical treatment and interventional radiology are required in a few cases. To determine the appropriate treatment strategy, it is important to preoperatively detect the presence and location of lymphatic leakage. However, the methods have yet to be established. We report a case in which lymphoscintigraphy with single-photon emission computerized tomography/computed tomography (SPECT/CT) was performed to evaluate pelvic lymphorrhea that occurred following total hysterectomy with pelvic and para-aortic lymphadenectomy for stage IIIA uterine sarcoma. Lymphoscintigraphy with SPECT/CT showed leakage of radioisotopes into the pelvic space, and intranodal lymphangiography was performed based on these findings. Following the procedure, the pelvic lymphorrhea improved, and no radioisotope leakage was confirmed by re-evaluation with lymphoscintigraphy with SPECT/CT. Our case indicates that lymphoscintigraphy with SPECT/CT may be useful for detecting the precise site of lymphatic leakage before interventional radiology or surgery.

Ultra-short Echo-time MR Angiography Combined with a Subtraction Method to Assess Intracranial Aneurysms Treated with a Flow-diverter Device.

A flow-diverter (FD) device is a well-established tool for the treatment of unruptured intracranial aneurysms. Time-of-flight (TOF) MR angiography (MRA) is widely used for postoperative assessment after the treatment with FD; however, it cannot fully visualize intra-aneurysmal and intrastent flow signals due to the magnetic susceptibility from the FD. Recently, the utility of MRA with ultra-short TE (UTE) sequence and arterial spin labeling technique in assessing the therapeutic efficacy of intracranial aneurysms treated with metallic devices has been reported, but long image acquisition time is one of the drawbacks of this method. Herein, we introduce a novel UTE MRA using the subtraction method that enables the reduction in susceptibility artifacts with a short image acquisition time.

Malignancy-related Hypercalcemia Caused by Metameric Cutaneous Metastasis of Parathyroid Hormone-related Protein-producing Bladder Carcinoma with Squamous Cell Differentiation: An Autopsy Case of Cobb Syndrome.

A 74-year-old woman was admitted with hypercalcemia and prolonged disturbance of consciousness. The left buttock to the anterior aspect of the left thigh was swollen and erythematous, with a collection of 1.0-cm large, firm, elastic nodules distributed in a zosteriform pattern in the L1-L4 region. Based on autopsy findings, a very rare case of Cobb syndrome was diagnosed due to a spinal vascular malformation at the Th12-L4 level and L5 vertebral hemangioma. Cobb syndrome-associated cutaneous metastasis extending along the same metamere was complicated by immunohistochemically proven parathyroid hormone-related protein-producing advanced bladder carcinoma in this case.

Recurrent bicycle falls by an elderly man who developed multiple intramuscular abscesses associated with urine leakage secondary to posterior urethral injury caused by pelvic ring disruption.

Key Clinical Message: With the aging of the population, physicians need to pay more attention to assessing the presence or absence of pelvic fractures and urinary retention associated with urethral injury due to such fractures in the elderly when falling from bicycles. Abstract: Walking ability does not rule out the presence of pelvic fractures. Many geriatric patients are likely to fall off bicycles. Physicians should pay more attention when assessing complications related to urethral trauma caused by pelvic fractures in the elderly after falling from bicycles.

Double inversion recovery MRI of subcortical band heterotopia and its variations.

BACKGROUND AND PURPOSE: Subcortical band heterotopia (SBH) is a malformation of cortical development diagnosed via MRI. Currently, patients with SBH are classified according to Di Donato's classification. We aimed to show a variation of SBH and the usefulness of double inversion recovery (DIR) images. METHODS: We retrospectively reviewed the MRI findings of 28 patients with SBH. The patients were classified according to Donato's classification by using conventional MR images, and their DIR findings were reviewed. RESULTS: Of 28 patients, 20 were grade 1 and 8 were grade 2 according to Di Donato's classification. In 15 of 28 patients, the following four types of atypical MRI findings were detected: asymmetry distribution (four cases), coexistence of thin and thick SBH (five cases), and DIR faint abnormal signal intensity in subcortical white matter (five cases) and in deep white matter (five cases). The latter two types were detected on DIR alone and have not been reported. Additionally, these were identified only in the mild group (Di Donato's classification 1-1 or 1-2). CONCLUSION: DIR is a useful MRI sequence for detecting faint white matter signal abnormalities, and it can aid in the accurate classification of SBH and identification of its variations, which may reflect the pathology of SBH.

Shallow epifaunal sea cucumber densities and their relationship with the benthic community in the Okinawa Islands.

Sea cucumbers are important ecological engineers in marine ecosystems. However, the fishery demand of some species, especially large-epifaunal and commercially used (LEC) sea cucumbers, has risen drastically, resulting in serious depletion of local populations for many species. Despite this problem, basic ecological data on sea cucumbers, such as population densities and preferred habitats, are often still insufficient. Here, we report on the population densities of multiple LEC sea cucumber species, and their ambient benthic communities at eight sites around Okinawa Islands. Further, we discuss the correspondence between sea cucumber densities and the surrounding coral communities. Our results show two sites within national or quasi-national parks, Aka and Manza, where stricter rules have been placed on fisheries and land reclamation compared to other areas, had the highest and third highest sea cucumber population densities among sites, respectively. Holothuria atra was observed at all survey sites and made up the majority of sea cucumber populations at all sites except for Chatan and Sesoko, where Holothuria leucospilota and Stichopus chloronotus were most abundant, respectively. Regarding the relationships between benthic composition and LEC sea cucumber species, S. chloronotus was significantly correlated with dead corals, scleractinian corals, and coralline algae. As well, H. leucospilota had significant correlations with rubble. Although there were no significant correlations between any specific scleractinian coral genus and sea cucumber densities, S. chloronotus was marginally insignificant with Platygyra and Psammocora. Notably, medium- to highly valued species were sparse in our surveys, and most of them appeared at only one site. Additionally, at one site (Odo), only three LEC sea cucumber individuals were observed. Combining these facts with relatively low population densities around the Okinawa Islands compared to densities reported in previous research from the Indo-West Pacific Ocean region, we conclude that Okinawan LEC sea cucumber populations have been and are being impacted by high levels of direct (e.g., overexploitation, as well as coastal development) and indirect anthropogenic pressure (e.g., decreasing water quality). To address the current situation, repeated monitoring and more detailed investigations to reveal the drivers that determine LEC sea cucumber species aggregations and population densities are urgently needed, along with more robust management of remaining LEC sea cucumber populations.

Successful Closure of External Iliac Artery Perforation with Super-selective Transcatheter Coil Embolization.

We present two cases of external iliac artery perforation occurring after endovascular interventions successfully treated with direct closure using super-selective transcatheter coil embolization. Two patients, one 78-year-old man and one 78-year-old woman, underwent cardiac catheterization via the right femoral approach for coronary artery disease and atrial fibrillation. Following the procedures, both patients suffered severe acute hypotension, and contrast-enhanced computed tomography revealed a massive retroperitoneal hematoma due to perforation of the right external iliac artery. We attempted direct perforation site closure with super-selective transcatheter embolization using microcoils and achieved complete hemostasis in both cases. Our technique could be an alternative treatment option for external iliac artery perforations associated with the endovascular intervention.