Prostate magnetic resonance imaging and the value of experience:An intrareader variability study

Objective To measure the intraobserver concordance of an experienced genitourinary radiologist reporting of multiparametric magnetic resonance imaging of the prostate(mpMRIp)scans over time.Methods An experienced genitourinary radiologist re-reported his original 100 consecutive mpMRIp scans using Prostate Imaging-Reporting and Data System version 2(PI-RADS v2)after 5 years of further experience comprising>1000 scans.Intraobserver agreement was measured using Cohen's kappa.Sensitivity,specificity,negative predictive value(NPV),positive predictive value(PPV),and accuracy were calculated,and comparison of sensitivity was performed using McNemar's test.Results Ninety-six mpMRIp scans were included in our final analysis.Of the 96 patients,53(55.2%)patients underwent subsequent biopsy(n=43)or prostatectomy(n=15),with 73 lesions targeted.Moderate agreement(Cohen's kappa 0.55)was seen in the number of lesions identified at initial reporting and on re-reading(81 vs.39 total lesions;and 71 vs.37 number of PI-RADS≥3 lesions).For clinically significant prostate cancer,re-reading demonstrated an increase in specificity(from 43%to 89%)and PPV(from 62%to 87%),but a decrease in sensitivity(from 94%to 72%,p=0.01)and NPV(from 89%to 77%).Conclusion The intraobserver agreement for a novice to experienced radiologist reporting mpMRIp using PI-RADS v2 is moderate.Reduced sensitivity is off-set by improved specificity and PPV,which validate mpMRIp as a gold standard for prebiopsy screening.

The risk of prostate cancer on incidental finding of an avid prostate uptake on 2-deoxy-2-[^(18)F]fluoro-D-glucose positron emission tomography/computed tomography for non-prostate cancer-related pathology:A single centre retrospective study

Objective:To review the risk of prostate cancer(PCa)in men with incidentally reported increased intraprostatic uptake at 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography/computed tomography(18F-FDG PET/CT)ordered at Department of Urology,The Wesley Hospital,Brisbane,QLD,Australia for non-PCa related pathology.Methods:Retrospective analysis of consecutive men between August 2014 and August 2019 presenting to a single institution for 18F-FDG PET/CT for non-prostate related conditions was conducted.Men were classified as benign,indeterminate,or malignant depending of the results of prostate-specific antigen(PSA),PSA velocity,biopsy histopathology,and three-Tesla(3 T)multiparametric MRI(mpMRI)Prostate Imaging Reporting and Data System score,or gallium-68-prostate-specific membrane antigen(68Ga-PSMA)PET/CT results.Results:Three percent(273/9122)of men demonstrated 18F-FDG avidity within the prostate.Eighty-five percent(231/273)were further investigated,including with PSA tests(227/231,98.3%),3 T mpMRI(68/231,29.4%),68Ga-PSMA PET/CT(33/231,14.3%),and prostate biopsy(57/231,24.7%).Results were considered benign in 130/231(56.3%),indeterminate in 31/231(13.4%),and malignant in 70/231(30.3%).PCa was identified in 51/57(89.5%)of the men who proceeded to biopsy,including 26/27(96.3%)men with Prostate Imaging Reporting and Data System scores 4-5 mpMRI and six men with a positive 68Ga-PSMA PET/CT.The most common Gleason score on biopsy was greater than or equal to 4+5(14/51,27.5%).68Ga-PSMA PET/CT was concordant with the 18F-FDG findings in 26/33(78.8%).All 13 men with a positive concordant 18F-FDG,3 T mpMRI,and 68Ga-PSMA PET/CT had PCa on biopsy.There was no statistically significant difference in the 18F-FDG maximum standardized uptake value between the benign or malignant groups(5.7 vs.6.1;p=0.580).Conclusion:In this study,after an incidental finding of an avid intraprostatic lesion on 18F-FDG PET/CT,70 of the 231 cases(30.3%;0.8%of the entire cohort)had results consistent with PCa,most commonly as Gleason score greater than or equal to 4+5 disease.Unless there is limited life expectancy due to competing medical co-morbidity,men with an incidental finding of intraprostatic uptake on 18F-FDG should be further investigated using principles of PCa detection.

Imaging of the Extra-axial Tumors and Tumor-like Lesions Involving both Middle and Posterior Cranial Fossae: Classification and Diagnosis

Objective: To study the imaging features of extra-axial tumors and tumor-likelesions involving both middle and posterior cranial fossae and to make a classification. Methods:Sixty cases of pathologically confirmed extra-axil tumors and tumor-like lesions involving bothmiddle and posterior cranial fossae were analyzed. They were divided into central and lateral types,the latter of which were subdivided into three types: middle cranial fossae type, posterior cranialfossae type and the over-riding type. The constitution and imaging features of each type wereanalyzed. Results: There were 12 cases of central type, including chordoma (n=5), pituitary adenoma(n=3), nasopharyngeal carcinoma (n=2), craniopharyn-gioma (n=1) and meningioma (n=l). 48 cases oflateral type including trigeminal nerve tumors (n=14), meningioma (n=12), epidermoid cyst (n=11),dural cavernous hemangioma (n=4), dermoid cyst (n=2), metastasis (n=2), hemangiopericytoma (n=1),paraganglioma of glonius jugular (n=1) and nasopharyngeal carcinoma (n=1). Each type of the lesionshad its own shape features, some of which were characteristic for some specific tumors. Most of thetumors and tumor-like lesions could be qualitatively diagnosed according to their imagingcharacteristics and the extent of the lesions could be defined definitely. Conclusion: It is helpfulto categorize extra-axial tumors and tumor-like lesions involving both middle and posterior cranialfossae according to their location for qualitative diagnosis and description of the extent of theselesions. It is of great clinical value in providing more precise and thorough imaging informationfor planning therapeutic methods and route of operation.

Role of diffusion-weighted magnetic resonance imaging in the differential diagnosis of focal hepatic lesions

AIM： To evaluate the utility of diffusion-weighted imaging （DWl） in screening and differential diagnosis of benign and malignant focal hepatic lesions. METHODS： Magnetic resonance imaging （MRI） examinations were performed using the Signa Excite Xl Twin Speed 1.5T system （GE Healthcare, Milwaukee, Wl, USA）. Seventy patients who had undergone MRI of the liver [29 hepatocellular carcinomas （HCC）, four cholangiocarcinomas, 34 metastatic liver cancers, 10 hemangiomas, and eight cysts] between April 2004 and August 2008 were retrospectively evaluated. Visualization of lesions, relative contrast ratio （RCR）, and apparent diffusion coefficient （ADC） were compared between benign and malignant lesions on DWl. Su- perparamagnetic iron oxide （SPIO） was administered to 59 patients, and RCR was compared pre- and postadministration.RESULTS： DWI showed higher contrast between malignant lesions （especially in multiple small metastatic cancers） and surrounding liver parenchyma than did contrast-enhanced computed tomography. ADCs （mean±SD × 10^-3 mm2/s） were significantly lower （P 〈 0.05） in malignant lesions （HCC： 1.31 ± 0.28 and liver metastasis： 1.11 ± 0.22） and were significantly higher in benign lesions （hemangioma： 1.84 ± 0.37 and cyst： 2.61 ± 0.45） than in the surrounding hepatic tissues. RCR between malignant lesions and surrounding he- patic tissues significantly improved after SPIO administration, but RCRs in benign lesions were not improved.CONCLUSION： DWI is a simple and sensitive method for screening focal hepatic lesions and is useful for differential diagnosis.

Brain activation and inhibition after acupuncture at Taichong and Taixi: resting-state functional magnetic resonance imaging

Acupuncture can induce changes in the brain. However, the majority of studies to date have focused on a single acupoint at a time. In the present study, we observed activity changes in the brains of healthy volunteers before and after acupuncture atTaichong （LR3） andTaixi （KI3） using resting-state functional magnetic resonance imaging. Fifteen healthy volunteers underwent resting-state functional magnetic resonance imaging of the brain 15 minutes before acupuncture, then received acupuncture atTaichong andTaixi using the nail-pressing needle insertion method, after which the needle was retained in place for 30 minutes. Fifteen minutes after withdrawal of the needle, the volunteers underwent a further session of resting-state functional magnetic res-onance imaging, which revealed that the amplitude of low-frequency lfuctuation, a measure of spontaneous neuronal activity, increased mainly in the cerebral occipital lobe and middle occipital gyrus （Brodmann area 18/19）, inferior occipital gyrus （Brodmann area 18） and cuneus （Brodmann area 18）, but decreased mainly in the gyrus rectus of the frontal lobe （Brodmann area 11）, inferi-or frontal gyrus （Brodmann area 44） and the center of the posterior lobe of the cerebellum. The present ifndings indicate that acupuncture atTaichong andTaixi speciifcally promote blood lfow and activation in the brain areas related to vision, emotion and cognition, and inhibit brain areas related to emotion, attention, phonological and semantic processing, and memory.

Imaging brain plasticity after trauma

The brain is highly plastic after stroke or epilepsy; however, there is a paucity of brain plasticity investigation after traumatic brain injury （TBI）. This mini review summarizes the most recent evidence of brain plasticity in human TBI patients from the perspective of advanced magnetic resonance imaging. Similar to other forms of acquired brain injury, TBI patients also demonstrat- ed both structural reorganization as well as functional compensation by the recruitment of other brain regions. However, the large scale brain network alterations after TBI are still unknown, and the field is still short of proper means on how to guide the choice of TBI rehabilitation or treat- ment plan to promote brain plasticity. The authors also point out the new direction of brain plas- ticity investigation.

Acupuncture for ischemic stroke:cerebellar activation may be a central mechanism following Deqi

The needling sensation of Deqi during acupuncture is a key factor of influencing acupuncture outcome.Recent studies have mainly focused on the brain function effects of Deqi in a physiological state.Functional magnetic resonance imaging（f MRI）on the effects of acupuncture at Waiguan（SJ5）in pathological and physiological states is controversial.In this study,12 patients with ischemic stroke received acupuncture at Waiguan（SJ5）and simultaneously underwent f MRI scanning of the brain,with imaging data of the activated areas obtained.Based on the patient＇s sensation,imaging data were allocated to either the Deqi group or non-Deqi group.In the Deqi group,the activated/deactivated areas were the left superior temporal gyrus（BA39）/right anterior lobe of the cerebellum and left thalamus.In the non-Deqi group,the activated areas included the medial frontal gyrus of the right frontal lobe（BA11）,right limbic lobe（BA30,35）,and left frontal lobe（BA47）,while the only deactivated area was the right parietal lobe（BA40）.Compared with the non-Deqi group,the Deqi group exhibited marked activation of the right anterior lobe of the cerebellum and right limbic lobe（BA30）.These findings confirm that the clinical effect of Deqi during acupuncture is based on brain functional changes.Cerebellar activation may be one of the central mechanisms of acupuncture in the treatment of ischemic stroke.

Biliary reflux detection in anomalous union of the pancreaticobiliary duct patients

AIM： To demonstrate the imaging findings of biliopan creatic and pancreatico-biliary reflux in patients with anomalous union of the pancreatico biliary duct （AUPBD） on gadoxetic acidenhanced functional magnetic resonance cholangiography （fMRC）.

Large animal models of human cauda equina injury and repair: evaluation of a novel goat model

Previous animal studies of cauda equina injury have primarily used rat models, which display significant differences from humans. Furthermore, most studies have focused on electrophysio- logical examination. To better mimic the outcome after surgical repair of cauda equina injury, a novel animal model was established in the goat. Electrophysiological, histological and magnetic resonance imaging methods were used to evaluate the morphological and functional outcome after cauda equina injury and end-to-end suture. Our results demonstrate successful establish- ment of the goat experimental model of cauda equina injury. This novel model can provide detailed information on the nerve regenerative process following surgical repair of cauda equina injury.

Identification of cerebral response to balloon distention of the bile duct

AIM: To identify the brain loci that process human biliary sensation. METHODS: In 6 patients (age range: 42-74 years; 4 men), who underwent percutaneous transhepatic biliary drainage (PTBD), the distal biliary tract was stimulated by repeatedly inflating the balloon of the PTBD catheter so that it reached volumes that produced a definite painless sensation. The functional magnetic resonance imaging (fMRI) of the cortical response to biliary sensation was examined. RESULTS: Biliary balloon stimulation elicited activation of the insular cortex, prefrontal cortex, and somato- sensory cortex (P < 0.001). CONCLUSION: Biliary balloon stimulation evoked a cerebral cortical response detectable by fMRI.

Molecular, Functional, and Structural Imaging of Major Depressive Disorder

Major depressive disorder（MDD） is a significant cause of morbidity and mortality worldwide,correlating with genetic susceptibility and environmental risk factors.Molecular,functional,and structural imaging approaches have been increasingly used to detect neurobiological changes,analyze neurochemical correlates,and parse pathophysiological mechanisms underlying MDD.We reviewed recent neuroimaging publications on MDD in terms of molecular,functional,and structural alterations as detected mainly by magnetic resonance imaging（MRI） and positron emission tomography.Altered structure and function of brain regions involved in the cognitive control of affective state have been demonstrated.An abnormal default mode network,as revealed by resting-state functional MRI,is likely associated with aberrant metabolicand serotonergic function revealed by radionuclide imaging.Further multi-modal investigations are essential to clarify the characteristics of the cortical network and serotonergic system associated with behavioral and genetic variations in MDD.

Skeletal Muscle Magnetic Resonance Imaging of the Lower Limbs in Late-onset Lipid Storage Myopathy with Electron Transfer Flavoprotein Dehydrogenase Gene Mutations

Background： Lipid storage myopathy （LSM） is a genetically heterogeneous group with variable clinical phenotypes. Late-onset multiple acyl-coenzyme A dehydrogenation deficiency （MADD） is a rather common form of LSM in China. Diagnosis and clinical management of it remain challenging, especially without robust muscle biopsy result and genetic detection. As the noninvasion and convenience, muscle magnetic resonance imaging （MRI） is a helpful assistant, diagnostic tool for neuromuscular disorders. However, the disease-specific MRI patterns of muscle involved and its diagnostic value in late-onset MADD have not been systematic analyzed. Methods： We assessed the MRI pattern and fat infiltration degree of the lower limb muscles in 28 late-onset MADD patients, combined with detailed clinical features and gene spectrum. Fat infiltration degree of the thigh muscle was scored while that ofgluteus was described as obvious or not. Associated muscular atrophy was defined as obvious muscle bulk reduction. Results： The mean scores were significantly different among the anterior, medial, and posterior thigh muscle groups. The mean of fat infiltration scores on posterior thigh muscle group was significantly higher than either anterior or medial thigh muscle group （P 〈 0.00 l）. Moreover, the mean score on medial thigh muscle group was significantly higher than that of anterior thigh muscle group （P 〈 0.01）. About half of the patients displayed fat infiltration and atrophy in gluteus muscles. Of 28 patients, 12 exhibited atrophy in medial and/ or posterior thigh muscle groups, especially in posterior thigh muscle group. Muscle edema pattern was not found in all the patients. Conclusions： Late-onset MADD patients show a typical muscular imaging pattern of fat infiltration and atrophy on anterior, posterior, and medial thigh muscle groups, with major involvement of posterior thigh muscle group and gluteus muscles and a sparing involvement of anterior thigh compartment. Our findings also suggest that muscle MRI of lower limbs is a helpful tool in guiding clinical evaluation on late-onset MADD.

Acupuncture Treatment Modulates the Resting-State Functional Connectivity of Brain Regions in Migraine Patients without Aura

Objective： To investigate the modulatory effect of acupuncture treatment on the resting-state functional connectivity of brain regions in migraine without aura （MWoA） patients. Methods： Twelve MWoA patients were treated with standard acupuncture treatment for 4 weeks. All MWoA patients received resting-state functional magnetic resonance imaging （fMRI） scanning before and after acupuncture treatment. Another 12 normal subjects matched in age and gender were recruited to serve as healthy controls. The changes of resting- state functional connectivity in MWoA patients before and after the acupuncture treatment and those with the healthy controls were compared. Results： Before acupuncture treatment, the MWoA patients had significantly decreased functional connectivity in certain brain regions within the frontal and temporal lobe when compared with the healthy controls. After acupuncture treatment, brain regions showing decreased functional connectivity revealed significant reduction in MWoA patients compared with before acupuncture treatment. Conclusions： Acupuncture treatment could increase the functional connectivity of brain regions in the intrinsic decreased brain networks in MWoA patients. The results provided further insights into the interpretation of neural mechanisms of acupuncture treatment for migraine.

A 92-year-old man with retropharyngeal hematoma caused by an injury of the anterior longitudinal ligament

Traumatic retropharyngeal hematoma is a rare condition and may be lethal in some cases. In patients with this condition, the absence of a vertebral fracture or a major vascular injury is extremely rare. We present the case of a 92-year-old man who hit his forehead by slipping on the floor in his house. He had no symptoms at the time; however, he experienced throat pain and dyspnea at 6 hours after the injury. On arrival, he complained of severe dyspnea; therefore, an emergency endotracheal intubation was performed. A lateral neck roentgenogram after intubation showed dilatation of the retropharyngeal and retrotracheal space and no evidence of a cervical vertebral fracture. Cervical computed tomography （CT） with contrast medium revealed a massive hematoma extending from the retropharyngeal to the superior mediastinal space but no evidence of contrast medium extravasation or a vertebral fracture. However, sagittal magnetic resonance imaging （MRI） revealed an anterior longitudinal ligament （C4-5 levels） injury. We determined that the cause of the hematoma was an anterior longitudinal ligament injury and a minor vascular injury around the injured ligament. Therefore, we recommend that patients with retropharyngeal hematoma undergo sagittal cervical MRI when roentgenography and CT reveal no evidenee of injury.