Pulmonary tumor embolism in renal cell carcinoma detected by hybrid CT and F18-PSMA PET.

We present the case of a 75-year-old female in which a pulmonary tumor embolism was detected incidentally on a prostate-specific membrane antigen positron emission tomography-computed tomography restaging scan. This occurred on the background of renal cell carcinoma in remission with pazopanib systemic therapy and a right nephrectomy 4 years prior. An avidity to prostate-specific membrane antigen in the superior lingula of the left upper lobe of the lung coupled with contrast-enhanced computed tomography findings found the lesion to be a tumor thrombus. This case serves to highlight the effectiveness of incorporating contrast-enhanced computed tomography with prostate-specific membrane antigen positron emission tomography and to consider the rare diagnosis of a pulmonary tumor embolism.

Long term nitrogen deficiency alters expression of miRNAs and alters nitrogen metabolism and root architecture in Indian dwarf wheat (Triticum sphaerococcum Perc.) genotypes.

The important roles of plant microRNAs (miRNAs) in adaptation to nitrogen (N) deficiency in different crop species especially cereals (rice, wheat, maize) have been under discussion since last decade with little focus on potential wild relatives and landraces. Indian dwarf wheat (Triticum sphaerococcum Percival) is an important landrace native to the Indian subcontinent. Several unique features, especially high protein content and resistance to drought and yellow rust, make it a very potent landrace for breeding. Our aim in this study is to identify the contrasting Indian dwarf wheat genotypes based on nitrogen use efficiency (NUE) and nitrogen deficiency tolerance (NDT) traits and the associated miRNAs differentially expressed under N deficiency in selected genotypes. Eleven Indian dwarf wheat genotypes and a high NUE bread wheat genotype (for comparison) were evaluated for NUE under control and N deficit field conditions. Based on NUE, selected genotypes were further evaluated under hydroponics and miRNome was compared by miRNAseq under control and N deficit conditions. Among the identified, differentially expressed miRNAs in control and N starved seedlings, the target gene functions were associated with N metabolism, root development, secondary metabolism and cell-cycle associated pathways. The key findings on miRNA expression, changes in root architecture, root auxin abundance and changes in N metabolism reveal new information on the N deficiency response of Indian dwarf wheat and targets for genetic improvement of NUE.

Upregulation of genes encoding plastidic isoforms of antioxidant enzymes and osmolyte synthesis impart tissue tolerance to salinity stress in bread wheat.

Wheat genotype Kharchia is a donor for salt tolerance in wheat breeding programs worldwide; however, the tolerance mechanism in Kharchia is yet to be deciphered completely. To avoid spending energy on accumulating organic osmolytes and to conserve resources for maintaining growth, plants deploy sodium (Na+) ions to maintain turgor. The enhanced ability to tolerate excess ion accumulation and ion toxicity is designated as tissue tolerance. In this study, salt-tolerant wheat genotype (Kharchia 65) and sensitive cultivars (HD2687, HD2009, WL711) were exposed to vegetative stage salinity stress (for four weeks). Kharchia 65 showed better tissue tolerance to salinity than the other genotypes based on different physiological parameters. Gene expression and abundance of chloroplast localized antioxidant enzymes and compatible osmolyte synthesis were upregulated by salinity in Kharchia 65. In Kharchia 65, the higher abundance of NADPH Oxidase (RBOH) transcripts and localization of reactive oxygen species (ROS) suggested an apoplastic ROS burst. Expression of calcium signaling genes of SOS pathway, MAPK6, bZIP6 and NAC4 were also upregulated by salinity in Kharchia 65. Considering that Kharchia local is the donor of salt tolerance trait in Kharchia 65, the publically available Kharchia local transcriptome data were analyzed. Our results and the in-silico transcriptome analysis also confirmed that higher basal levels and the stress-induced rise in the expression of plastidic isoforms of antioxidant enzymes and osmolyte biosynthesis genes provide tissue tolerance in Kharchia 65. Thus, in salinity tolerant genotype Kharchia 65, ROS burst mediated triggering of calcium signaling improves Na+ exclusion and tissue tolerance to Na+. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-022-01237-w.

18F DCFPyL PSMA avid biopsy proven subcutaneous capillary haemangioma as a malignancy mimic in the setting of biochemical recurrent prostate carcinoma.

We present a case of a 65-year-old male with a biopsy proven subcutaneous capillary haemangioma identified on imaging for evaluation of further metastatic spread of prostatic carcinoma due to a rise in his prostate-specific antigen biochemistry. He was receiving salvage radiation therapy for his known isolated nodal disease, four years after prostatectomy. An intensely avid prostate-specific membrane antigen positron emission tomography-computed tomography lesion in the left paramedian back at the level of L1 was noted on his scan. A core biopsy revealed a dermal haemangioma with no evidence of metastatic prostatic carcinoma. To our knowledge, only one other incidental case of prostate-specific membrane antigen avid subcutaneous capillary haemangioma has been described in the literature. Whilst uncommon, incidental findings of prostate-specific membrane antigen PET avid dermal lesions are pathognomonic for haemangiomas and can be treated as "no touch" lesions with watchful observation.

18F-FDG PET, contrast CT and MRI to comprehensively diagnose and assess rare perineural spread of squamous cell carcinoma to the greater auricular nerve.

We present a case of a 78-year-old male with a primary parotid squamous cell carcinoma which spread via the left facial, trigeminal and greater auricular nerves. The patient presented with left facial droop and paraesthesia. Initial MRI scans demonstrated involvement of the trigeminal and facial nerves with no sign of a primary lesion. Abnormal enhancement within the left parotid substance on FDG PET-CT demonstrated the primary malignancy which was confirmed on histology by core biopsy. There was also focal avidity along the course of the left greater auricular nerve consistent with perineural infiltration, extending from the posterior aspect of the parotid to the left cervical plexus at C2/C3. To our knowledge, this is the second case of squamous cell carcinoma perineural spread to the greater auricular nerve imaged on FDG PET-CT scanning. This case highlights the importance of multimodality imaging correlation in the workup of primary head and neck malignancies and associated perineural spread, which is essential in adjuvant radiation therapy planning to reduce local recurrence, improve prognosis and overall survival.

Genome-Wide Identification and Expression Analysis of the Thioredoxin (Trx) Gene Family Reveals Its Role in Leaf Rust Resistance in Wheat (Triticum aestivum L.).

Bread wheat (Triticum aestivum L.; Ta) is the staple cereal crop for the majority of the world's population. Leaf rust disease caused by the obligate fungal pathogen, Puccinia triticina L., is a biotrophic pathogen causing significant economic yield damage. The alteration in the redox homeostasis of the cell caused by various kinds of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in response to pathogenic infections is controlled by redox regulators. Thioredoxin (Trx) is one of the redox regulators with low molecular weight and is thermostable. Through a genome-wide approach, forty-two (42) wheat Trx genes (TaTrx) were identified across the wheat chromosome groups A, B, and D genomes containing 12, 16, and 14 Trx genes, respectively. Based on in silico expression analysis, 15 TaTrx genes were selected and utilized for further experimentation. These 15 genes were clustered into six groups by phylogenetic analysis. MicroRNA (miRNA) target analysis revealed eight different miRNA-targeted TaTrx genes. Protein-protein interaction (PPI) analysis showed TaTrx proteins interact with thioredoxin reductase, peroxiredoxin, and uncharacterized proteins. Expression profiles resulting from quantitative real-time PCR (qRT-PCR) revealed four TaTrx genes (TaTrx11-5A, TaTrx13-5B, TaTrx14-5D, and TaTrx15-3B) were significantly induced in response to leaf rust infection. Localization of ROS and its content estimation and an assay of antioxidant enzymes and expression analysis suggested that Trx have been involved in ROS homeostasis at span 24HAI-72HAI during the leaf rust resistance.

Interactive effect of elevated CO2 and nitrogen dose reprograms grain ionome and associated gene expression in bread wheat.

Wheat crop grown under elevated CO2 (EC) often have a lowered grain nitrogen (N) and protein concentration along with an altered grain ionome. The mechanistic understanding on the impact of CO2 x N interactions on the grain ionome and the expression of genes regulating grain ionome is scarce in wheat. In the present study, the interactive effect of EC and N dosage on grain yield, grain protein, grain ionome, tissue nitrate, and the expression of genes contributing to grain ionome (TaNAM-B1 and TaYSL6) are described. Three bread wheat genotypes were evaluated under two CO2 levels (Ambient CO2 (AC) of 400 ± 10 ppm and elevated CO2 (EC) of 700 ± 10 ppm) and two N levels (Low (LN) and Optimum N (ON). In EC, wheat genotypes HD2967 and HI 1500 recorded a significant decrease in grain nitrate content, while leaf and stem nitrate showed a significant increase. BT. Schomburgk (BTS), showed a significant increase in unassimilated nitrate and a decline in grain N and grain protein under EC. There was a general decline of grain ionome (N, P, K, Ca, Fe) in EC, except for grain Na content. The expression of genes TaNAM-B1 and TaYSL6 associated with protein and micronutrient remobilization to grains during senescence were affected by both EC and N treatments. For instance, in flag leaves of BTS, the expression of TaNAM-B1 and TaYSL6 were lower in EC-LN compared to AC-LN. In maturing spikes, transcript abundance of TaNAM-B1 and TaYSL6 were lower in EC in BTS. The altered transcript abundance of TaYSL6 and TaNAM-B1 in source and sink supports the change in grain ionome and suggests an N dependent transcriptional reprogramming in EC.

Analysis of NIA and GSNOR family genes and nitric oxide homeostasis in response to wheat-leaf rust interaction.

Nitric oxide (NO) modulates plant response to biotic and abiotic stresses by S-nitrosylation-mediated protein post-translational modification. Nitrate reductase (NR) and S-nitrosoglutathione reductase (GSNOR) enzymes are essential for NO synthesis and the maintenance of Nitric oxide/S-nitroso glutathione (NO/GSNO) homeostasis, respectively. S-nitrosoglutathione, formed by the S-nitrosylation reaction of NO with glutathione, plays a significant physiological role as the mobile reservoir of NO. The genome-wide analysis identified nine NR (NIA) and three GSNOR genes in the wheat genome. Phylogenic analysis revealed that the nine NIA genes +were clustered into four groups and the 3 GSNORs into two groups. qRT-PCR expression profiling of NIAs and GSNORs was done in Chinese spring (CS), a leaf rust susceptible wheat line showing compatible interaction, and Transfer (TR), leaf rust-resistant wheat line showing incompatible interaction, post-inoculation with leaf rust pathotype 77-5 (121-R-63). All the NIA genes showed upregulation during incompatible interaction in comparison with the compatible reaction. The GSNOR genes showed a variable pattern of expression: the TaGSNOR1 showed little change, whereas TaGSNOR2 showed higher expression during the incompatible response. TaGSNOR3 showed a rise of expression both in compatible and incompatible reactions. Before inoculation and after 72 h of pathogen inoculation, NO localization was studied in both compatible and incompatible reactions. The S-nitrosothiol accumulation, NR, and glutathione reductase activity showed a consistent increase in the incompatible interactions. The results demonstrate that both NR and GSNOR plays significant role in defence against the leaf rust pathogen in wheat by modulating NO homeostasis or signalling.

Expression dynamics of genes encoding nitrate and ammonium assimilation enzymes in rice genotypes exposed to reproductive stage salinity stress.

Understanding the reproductive stage salinity stress tolerance is a key target for breeding stress tolerant rice genotypes. Nitrate and ammonium are equally important nitrogen forms utilized by rice. We evaluated nitrate and ammonium assimilation during reproductive stage in control and salinity (10dSm-1 using NaCl) stressed rice plants. Osmotic stress tolerant rice genotype Shabhagidhan (SD) and high yielding yet osmotic and salinity stress sensitive genotype Pusa sugandh-5 (PS5) were evaluated. Salinity stress was given to plants during panicle emergence and flag leaves was collected after 1d, 3d 5d, 7d, 9d,12d and 15d after anthesis. Reproductive stage salinity stress resulted in decrease of membrane stability, relative water content and osmotic potential of rice plants. Reproductive stage salinity stress decreased the expression of nitrate reductase (OsNIA), nitrite reductase (OsNiR), Glutamine synthetase (OsGLN1.1, OsGLN1.2, OsGLN2) and glutamate synthase/GOGAT (OsFd-GOGAT, OsNADH-GOGAT) in flag leaves. In response to stress, SD showed better stress tolerance than PS5 in terms of higher yield stability. Variety SD showed higher leaf nitrate and ammonium content and maintained comparatively higher nitrate and ammonia metabolism enzyme activity than PS5. Salinity stress upregulated the activity of glutamate dehydrogenase enzyme and indirectly contributed to the higher proline content and maintenance of favourable osmotic potential in SD. Expression of GS2 which has role in photo respiratory ammonia assimilation was upregulated by salinity stress in PS5 in comparison to SD. Rice genotype showing better induction of nitrogen assimilatory genes will be more tolerant to reproductive stage salinity stress.

Tumour-capsule interface measured on 18F-DCFPyL PSMA positron emission tomography/CT imaging comparable to multi-parametric MRI in predicting extra-prostatic extension of prostate cancer at initial staging.

INTRODUCTION: Nerve-sparing prostatectomy is recommended in cases of organ-confined prostate cancer but is generally contraindicated in patients with suspected extra-prostatic extension (EPE). PSMA ligand imaging has been shown to be valuable in predicting EPE when performed on a hybrid PET/MRI scanner; however, the majority of PSMA PET imaging is performed using PSMA-PET. To our knowledge, there are no established PET/CT criteria for assessing EPE. In this study, we aim to provide a reproducible method for evaluating EPE on PSMA-PET/CT imaging and assess its utility compared with MRI. METHODS: Imaging findings and histopathology were reviewed for 100 consecutive patients who underwent a radical prostatectomy after imaging with MRI and 18F-DCFPyL PSMA-PET/CT. RESULTS: A broad tumour-capsule interface measured using a standardised technique on fused PSMA-PET/CT imaging is associated with a higher risk for established EPE (P < 0.001). In our cohort, applying the criteria of tumour-capsule contact ≥ 10 mm measured on PET/CT was as sensitive as applying PI-RADS version 2 criteria to mpMRI imaging for predicting EPE (74% and 79%, respectively, P = 0.11) and had superior specificity (86% and 61%, respectively, P = 0.035). 93% of MRI-occult lesions were visualised on PSMA-PET/CT. Applying the proposed PET/CT criteria for EPE to this subgroup of 14 patients yielded a sensitivity of 67% and specificity of 92%. CONCLUSION: Our results suggest that tumour-capsule interface measured on fused F18-DCFPyL PSMA-PET/CT imaging is comparable to MRI criteria for predicting the presence of EPE. Applying PET/CT criteria may be of particular benefit in predicting EPE in patients with MRI-occult prostate cancer.

Primary myelofibrosis: spectrum of imaging features and disease-related complications.

Primary myelofibrosis is a chronic clonal stem cell disorder that results in a build-up of marrow fibrosis and dysfunction, hypermetabolic states, and myeloid metaplasia. The clinical and radiological consequences can be quite diverse and range from the manifestations of osteosclerosis and extramedullary haematopoiesis to thrombohaemorrhagic complications from haemostatic dysfunction. In addition, there is the challenge of identifying less well-recognised sites of extramedullary haematopoiesis and their site-specific complications. The intent of this article is to illustrate the spectrum of primary myelofibrosis as declared though multimodality imaging, with examples of both common and rarer disease manifestations.

Acute saddle pulmonary embolism on 18F-FDG PET/CT: diagnosis by functional imaging.

18F-labelled fluoro-2-deoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) is used extensively in the setting of cancer staging and in assessing cancer treatment response. Oncology patients have a sevenfold risk of developing pulmonary embolism (PE) due to underlying activation of the haemostatic system and anti-cancer therapy inducing a hypercoagulable state. The diagnosis of PE on 18F-FDG PET/CT is challenging, particularly in the absence of intravenous contrast. The case of a female patient undergoing treatment for advanced diffuse large B-cell lymphoma is presented. The ancillary signs of PE are illustrated on consecutive non-contrast-enhanced 18F-FDG PET/CT scans. The signs include the "rim sign" relating to regions of pulmonary infarction and abnormal cardiac uptake indicating right heart strain. The diagnosis was confirmed on CT pulmonary angiography which demonstrated extensive PE, including a saddle embolus.

The role of 18F-FDG-PET/CT in evaluating retroperitoneal masses -Keeping your eye on the ball!

BACKGROUND: Testicular germ cell tumour is the commonest malignancy affecting males aged between 15 and 35, with an increased relative risk amongst those with a history of cryptorchidism. In patients presenting with locoregional metastatic disease, retroperitoneal and pelvic soft tissue masses are common findings on ultrasound and computed tomography, which has several differential diagnoses within this demographic cohort. On staging 18F-FDG-PET/CT, understanding the typical testicular lymphatic drainage pathway facilitates prompt recognition of the pathognomonic constellation of unilateral absence of testicular scrotal activity, and FDG-avid nodal masses along the drainage pathway. We describe the cases of three young males presenting with abdominopelvic masses, in whom FDG-PET/CT was helpful in formulating a unifying diagnosis of metastatic seminoma, retrospectively corroborated by a history of testicular maldescent. CASE PRESENTATIONS: In all three cases, the patients were males aged in their 30s and 40s who were brought to medical attention for back and lower abdominal pain of varying duration. Initial imaging evaluation with computed tomography and/or ultrasound revealed large abdominopelvic soft tissue masses, with lymphoproliferative disorders or soft tissue sarcomas being high on the list of differential diagnoses. As such, they were referred for staging FDG-PET/CT, all of whom demonstrated the pathognomonic constellation of, 1) unilateral absence of scrotal testicular activity, and 2) FDG-avid nodal masses along the typical testicular lymphatic drainage pathway. These characteristic patterns were corroborated by a targeted clinical history and examination which revealed a history of cryptorchidism, and elevated ß-hCG in two of three patients. All were subsequently confirmed as metastatic seminoma on biopsy and open resection. CONCLUSION: These cases highlight the importance of clinical history and examination for the clinician, as well as a sound knowledge of the typical testicular lymphatic drainage pathway for the PET physician, which would assist with prompt recognition of the characteristic imaging patterns on FDG-PET/CT. It further anecdotally supports the utility of FDG-PET/CT in evaluating undiagnosed abdominopelvic masses, as well as a potential role in the initial staging of germ cell tumours in appropriately selected patients.

Angioplasty versus stenting for infrapopliteal arterial lesions in chronic limb-threatening ischaemia.

BACKGROUND: Chronic limb-threatening ischaemia (CLTI) is a manifestation of peripheral arterial disease (PAD) that includes chronic ischaemic rest pain or ischaemic skin lesions, ulcers, or gangrene for longer than two weeks. The severity of the disease depends on the extent of arterial stenosis and the availability of collateral circulation. Treatment for CLTI aims to relieve ischaemic pain, heal ischaemic ulcers, prevent limb loss, improve quality of life, and prolong survival. CLTI due to occlusive disease in the infrapopliteal arterial circulation (below-knee circulation) can be treated via an endovascular technique by a balloon opening the narrowed vessel, so called angioplasty, with or without the additional deployment of a scaffold made of metal alloy or other material, so called stenting. Endovascular interventions in the infrapopliteal vasculature may improve symptoms in patients with CLTI by re-establishing in-line blood flow to the foot. Controversy remains as to whether a balloon should be used alone to open the vessel, or whether a stent should also be deployed. OBJECTIVES: To determine the efficacy and safety of percutaneous transluminal angioplasty (PTA) alone versus PTA with stenting of infrapopliteal arterial lesions (anterior tibial artery, posterior tibial artery, fibular artery (formerly known as peroneal artery), and common tibioperoneal trunk) for patients with chronic limb-threatening ischaemia (CLTI). SEARCH METHODS: The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL, and AMED databases, as well as World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 25 June 2018. We applied no language restrictions. SELECTION CRITERIA: We planned to include randomised or quasi-randomised controlled trials comparing PTA versus PTA with a stent and including patients aged 18 years or over with CLTI. We defined CLTI as Fontaine stage III (ischaemic rest pain) and IV (ischaemic ulcers or gangrene) or consistent with Rutherford category 4 (ischaemic rest pain), 5 (minor tissue loss), and 6 (major tissue loss), with stenotic (> 50% luminal loss) or occluded infrapopliteal artery, including tibiofibular trunk, anterior tibial artery, posterior tibial artery, and fibular artery. We included all types of stents irrespective of design (e.g. bare-metal, drug-eluting, bio-absorbable). DATA COLLECTION AND ANALYSIS: Two review authors (CC-TH and GNCK) independently selected suitable trials, assessed trial quality, and extracted data. An additional third review author (MLvD) assessed trial quality and, when necessary, acted as arbiter for study selection and data extraction. Outcomes included technical success of the procedure, procedural complications, patency, major amputation, and mortality. We assessed the quality of evidence using the GRADE approach. MAIN RESULTS: We included in the review seven trials with 542 participants. One trial randomised limbs to undergo PTA alone or PTA with stent placement, and the remaining studies randomised participants. Five trials with 476 participants show that the technical success rate was greater in the stent group than in the angioplasty group (odds ratio (OR) 3.00, 95% confidence interval (CI) 1.14 to 7.93; 476 lesions; 5 studies; I² = 23%). Meta-analysis of three eligible trials with 456 participants did not show a clear difference in short-term (within six months) patency between infrapopliteal arterial lesions treated with PTA and those treated with PTA and stenting (OR 0.88, 95% CI 0.37 to 2.11; 456 lesions; 3 studies; I² = 77%). Results also did not show clear differences between treatment groups in procedure complication rate (OR 0.87, 95% CI 0.01 to 53.60; 360 participants; 5 studies; I² = 85%), rate of major amputations at 12 months (OR 1.34, 95% CI 0.56 to 3.22; 306 participants; 4 studies; I² = 0%), and rate of mortality at 12 months (OR 0.71, 95% CI 0.43 to 1.17; 497 participants; 6 studies; I² = 0%). Heterogeneity between studies was high for the outcomes procedure complications and primary patency. The overall methodological quality of the trials included in this review was moderate due to selection and performance bias. Studies used different regimens for pretreatment and post-treatment antiplatelet/anticoagulant medication. We downgraded the certainty of the overall evidence for all outcomes by one level to moderate due to inconsistency of results across studies and large confidence intervals (small numbers of trials and participants). AUTHORS' CONCLUSIONS: Trials show that the immediate technical success rate of restoring luminal patency is higher in the stent group but reveal no clear differences in short-term patency at six months between infrapopliteal arterial lesions treated with PTA with stenting versus those treated with PTA without stenting. We ascertained no clear differences between groups in periprocedural complications, major amputation, and mortality. However, use of different regimens for pretreatment and post-treatment antiplatelet/anticoagulant medication and the duration of its use within and between trials may have influenced the outcomes. Limited currently available data suggest that high-quality evidence is insufficient to show that PTA with stent insertion is superior to use of standard PTA alone without stenting for treatment of infrapopliteal arterial lesions. Further studies should standardise the use of antiplatelets/anticoagulants before and after the intervention to improve the comparability of the two treatments.

More than the prostate: Intrapancreatic accessory spleen and papillary thyroid cancer detected with 18F-PSMA PET/CT.

OBJECTIVE: Prostate specific membrane antigen (PSMA) positron emission tomography diagnostic computed tomography (PET/CT) is gaining an increasing role in the staging of prostate cancer and restaging in cases of biochemical recurrence. Our understanding of PSMA affinity for incidental pathological and non-pathological entities is also maturing although certain cases do present as diagnostic and management dilemmas. SUBJECT AND METHODS: We present a case of a 55 years old man with prostate adenocarcinoma, with incidentally found pancreatic and thyroid lesions showing PSMA avidity. RESULTS: We were able to utilize a heat damaged red blood cell single photon emission tomography (SPET)/CT scan and ultrasound guided fine needle aspiration (FNA) to accurately diagnose co-existent thyroid papillary carcinoma and intra-pancreatic accessory spleen (IPAS) tissue, respectively. The patient avoided invasive pancreatic tissue sampling and subsequent staging with fluorine-18 fluorodeoxyglucose (18F-FDG) PET/CT. CONCLUSION: This is the first case to our knowledge describing both such lesions in one patient and the first case describing the use of 2-(3-{1-carboxy-5-[(6-[18F]fluoro-pyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid (18F-DCFPyL)-PSMA PET/CT to detect IPAS. Furthermore we highlight the value of nuclear medicine diagnostic work up in complex cases.

High resolution magnetic resonance imaging for exposing facial nerve zonal vulnerability to microbleeds: A rare cause of facial palsy.

Background We report a case of hypertensive microbleeds strategically located at the attached segment (AS) and root entry zone (REZ) at the left facial nerve causing facial paralysis. Case Report A 60-year-old woman presented with sudden onset left facial paralysis. Medical history was significant for poorly controlled hypertension secondary to bilateral adrenal hyperplasia (primary hyperaldosteronism). The patient was initially treated for presumptive Bell's palsy. Subsequent magnetic resonance imaging of the brain and internal auditory canal showed two microbleeds at the left cerebellopontine angle. Dedicated coronal T1 magnetization prepared rapid acquisition gradient echo and T2 sampling perfection with application optimized contrasts using different flip angle evolution sequences revealed two acute microbleeds located at the attached AS and REZ of the left facial nerve. The patient experienced only partial recovery from House-Brackmann grade IV facial paralysis at presentation to a House-Brackmann grade III facial paralysis at 1 year of follow up. Conclusions To the best of the authors' knowledge, this is the first reported case of facial paralysis caused by microbleeds directly affecting the vulnerable AS and REZ facial nerve segments. We discuss the zonal microanatomy of the facial nerve and the crucial role of high resolution MRI for diagnosis.

Serial magnetic resonance imaging findings of intracerebral spread of listeria utilising subcortical U-fibres and the extreme capsule.

We present a case of Listeria monocytogenes cerebral abscess with axonal spread via the subcortical U-fibres and extreme capsule on magnetic resonance imaging, with follow-up studies demonstrating serial reduction in oedema and enhancement pattern of the white-matter fibre tracts following antimicrobial treatment. We discuss the microbiological mechanism of bacterial mobility to account for these unique imaging features. Recognition of this distinct pattern of spread of L. monocytogenes cerebral abscess may aid in diagnosis and enable early microbiological culture and treatment.

Principles and Clinical Application of Dual-energy Computed Tomography in the Evaluation of Cerebrovascular Disease.

Dual-energy computed tomography (DECT) simultaneously acquires images at two X-ray energy levels, at both high- and low-peak voltages (kVp). The material attenuation difference obtained from the two X-ray energies can be processed by software to analyze material decomposition and to create additional image datasets, namely, virtual noncontrast, virtual contrast also known as iodine overlay, and bone/calcium subtraction images. DECT has a vast array of clinical applications in imaging cerebrovascular diseases, which includes: (1) Identification of active extravasation of iodinated contrast in various types of intracranial hemorrhage; (2) differentiation between hemorrhagic transformation and iodine staining in acute ischemic stroke following diagnostic and/or therapeutic catheter angiography; (3) identification of culprit lesions in intra-axial hemorrhage; (4) calcium subtraction from atheromatous plaque for the assessment of plaque morphology and improved quantification of luminal stenosis; (5) bone subtraction to improve the depiction of vascular anatomy with more clarity, especially at the skull base; (6) metal artifact reduction utilizing virtual monoenergetic reconstructions for improved luminal assessment postaneurysm coiling or clipping. We discuss the physical principles of DECT and review the clinical applications of DECT for the evaluation of cerebrovascular diseases.