Multiphase Magnetic Resonance Research Articles

The Weight of Risk: Exploring the Link Between Obesity and Liver Cancer

Obesity is a chronic, preventable condition, and has a significant public health concern. Its implications extend beyond metabolic syndrome, casting a shadow over the development and prognosis of various cancers, with a particularly strong tie to hepatocellular carcinoma (HCC) among all cancer types. Non-Alcoholic Fatty Liver Disease (NAFLD) is now a leading cause of liver cancer, along with the treatment of hepatitis B and C. Liver cancer is the fourth most common cause of cancer related deaths worldwide, with obesity, exacerbating the risk especially two times higher in Body Mass Index (BMI) above 30 and four times higher in BMI above 35. Visceral adiposity, measured by waist circumference, is considered more important risk factor than general adiposity. Several mechanisms have been proposed to explain the pathophysiology of how obesity can trigger HCC, but the precise mechanisms that control the progression from steatosis to steatohepatitis and tumor initiation remain unclear. Hepatocellular cancer may occur in patients with NAFLD without cirrhosis. The diagnosis of HCC in NAFLD can be challenging due to an increase in poor-quality ultrasound in obese individuals, which necessitates a more accurate and cost-effective surveillance strategy for early detection. The delay in diagnosis, older age, and the presence of relevant comorbidities limit the possibility of therapeutic intervention. Weight management through lifestyle changes and surgical interventions like bariatric surgery offers promise in mitigating both metabolic syndrome and the risk of HCC. Diagnosis hinges on advanced imaging techniques like multiphase Magnetic Resonance Imaging or Computed Tomography scan using specific criteria. Treatment modalities for HCC are multifaceted, depends upon tumor characteristics, metastasis, cirrhosis, and overall liver function. However, despite advancements, there remains a pressing need for more efficacious interventions to combat obesity and curb the trajectory of HCC, given its persistently high mortality rate. Surveillance protocols for HCC in cirrhotic patients entail regular abdominal ultrasounds with or without Alpha Fetoprotein testing at six-month intervals. However, there is a need for cost effective surveillance strategies for HCC in non-cirrhotic NAFLD.

Multi-phasic magnetic resonance imaging of hemodynamic interchanges in hepatocarcinogenesis

BackgroundLiver cirrhosis and hepatocellular cancer deem a substantial global health burden and are the end result of a variety of chronic liver diseases. Guidelines have been introduced to secure standardized approaches in the diagnosis and management of hepatocellular carcinoma (HCC). Established guidelines agree upon the distinctive dynamic enhancement findings of HCC, characterized by arterial phase wash-in and venous or delayed phase washout. The indeterminate focal hepatic lesions constitute a diagnostic dilemma. The aim of the study was quantification of hepatic vascular parameters using dynamic contrast-enhanced (DCE)-MRI to study liver hemodynamic disturbances that can differentiate between focal hepatic lesions during hepatocellular carcinogenesis.ResultsThe study was conducted on 95 patients with comparing perfusion abnormalities across different liver cirrhosis pathologies, and the comparison revealed the correlation of hemodynamics with hepatocarcinogenesis and grades of cirrhosis. Relative enhancement curves were graphed to illustrate the different enhancement patterns across the spectrum of hepatonodular lesions of cirrhosis and among types of de novo and recurrent HCC. Statistical significance was highest between dysplastic nodules (DNs) and HCCs (maximal relative enhancement (MRE) 0.88, wash-in ratio (WIR) 0.84, washout ratio (WOR) 0.78, time to peak (TTP) 0.74, area under curve (AUC 0.73, T0 0.70), compared to those between cirrhotic liver and DNs (MRE 0.74, To 0.62). Least significances were between de novo and recurrent HCCs (TTP 0.66, r AUC 0.66, MRE 0.63). Performances between non-cirrhotic and cirrhotic liver [WOR 0.81, time to peak (TTP) 0.80, r AUC 0.63] surpassed those among different grades of cirrhosis (the highest was between non-tumoral and tumoral cirrhosis: TTP 0.74, MRE 0.68, WIR 0.65, WOR 0.65).ConclusionsDynamic contrast-enhanced magnetic resonance imaging hemodynamic metrics promise potential usefulness as non-invasive biomarkers in assessment of liver cirrhosis, characterization of cirrhotic nodules, and evaluation of multistep hepatocarcinogenesis.

A newly developed patient fixation system using a dedicated mouthpiece and dental impression materials for head and neck radiotherapy: a preliminary study.

We evaluated the basic characteristics and efficacy of our newly developed patient fixation system for head and neck radiotherapy that uses a dedicated mouthpiece and dental impression materials. The present investigation demonstrated that with this system, the changes in the absorbed dose to water depending on the material of the mouthpiece were small, with a maximum of 0.32% for a 10-MV photon beam. For the dental impression material, we selected a silicone material with the lowest Hounsfield unit (HU) value that had little effect on the generation of artifacts and the quality of the X-ray beam. Multiphase magnetic resonance imaging (MRI) revealed that the head-up and -down motions in the thermoplastic shell without the mouthpiece were 5.76 ± 1.54 mm, whereas the motion with the mouthpiece decreased significantly to 1.72 ± 0.92 mm (P = 0.006). Similarly, the head-left and -right motion displacement decreased from 6.32 ± 1.86 mm without the mouthpiece to 1.80 ± 0.42 mm with the mouthpiece (P = 0.003). Regarding the tongue depressor function of the mouthpiece, the median distance from the hard palate to the surface of the tongue was 28.42 mm. The present results indicate that the new immobilization device developed herein that uses a mouthpiece and a thermoplastic shell is useful for suppressing patients’ head motions and tongue positions.

Radiomic analysis based on multi-phase magnetic resonance imaging to predict preoperatively microvascular invasion in hepatocellular carcinoma.

BACKGROUNDThe prognosis of hepatocellular carcinoma (HCC) remains poor and relapse occurs in more than half of patients within 2 years after hepatectomy. In terms of recent studies, microvascular invasion (MVI) is one of the potential predictors of recurrence. Accurate preoperative prediction of MVI is potentially beneficial to the optimization of treatment planning.AIMTo develop a radiomic analysis model based on pre-operative magnetic resonance imaging (MRI) data to predict MVI in HCC.METHODSA total of 113 patients recruited to this study have been diagnosed as having HCC with histological confirmation, among whom 73 were found to have MVI and 40 were not. All the patients received preoperative examination by Gd-enhanced MRI and then curative hepatectomy. We manually delineated the tumor lesion on the largest cross-sectional area of the tumor and the adjacent two images on MRI, namely, the regions of interest. Quantitative analyses included most discriminant factors (MDFs) developed using linear discriminant analysis algorithm and histogram analysis with MaZda software. Independent significant variables of clinical and radiological features and MDFs for the prediction of MVI were estimated and a discriminant model was established by univariate and multivariate logistic regression analysis. Prediction ability of the above-mentioned parameters or model was then evaluated by receiver operating characteristic (ROC) curve analysis. Five-fold cross-validation was also applied via R software.RESULTSThe area under the ROC curve (AUC) of the MDF (0.77-0.85) outperformed that of histogram parameters (0.51-0.74). After multivariate analysis, MDF values of the arterial and portal venous phase, and peritumoral hypointensity in the hepatobiliary phase were identified to be independent predictors of MVI (P < 0.05). The AUC value of the model was 0.939 [95% confidence interval (CI): 0.893-0.984, standard error: 0.023]. The result of internal five-fold cross-validation (AUC: 0.912, 95%CI: 0.841-0.959, standard error: 0.0298) also showed favorable predictive efficacy.CONCLUSIONNoninvasive MRI radiomic model based on MDF values and imaging biomarkers may be useful to make preoperative prediction of MVI in patients with primary HCC.

Altered glymphatic enhancement of cerebrospinal fluid tracer in individuals with chronic poor sleep quality

Chronic sleep disturbance is a risk factor for dementia disease, possibly due to impaired sleep-dependent clearance of toxic metabolic by-products. We compared enrichment of a cerebrospinal fluid (CSF) tracer within brain of patients reporting good or poor sleep quality, assessed by the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Tracer enrichment in a selection of brain regions was assessed using multiphase magnetic resonance imaging up to 48 hours after intrathecal administration of the contrast agent gadobutrol (0.5 ml of 1 mmol/ml) serving as tracer. Tracer enrichment differed between patients with good (PSQI ≤5) and poor (PSQI >5) sleep quality in a cohort of non-dementia individuals (n = 44; age 42.3 ± 14.5 years), and in patients with the dementia subtype idiopathic normal pressure hydrocephalus (n = 24; age 71.0 ± 4.9 years). Sleep impairment was associated with increased CSF tracer enrichment in several brain regions. Cortical brain volume as well as entorhinal cortex thickness was reduced in the oldest cohort and was correlated with the severity of sleep disturbance and the degree of cortical tracer enrichment. We suggest chronic sleep disturbance is accompanied by altered glymphatic function along enlarged perivascular spaces.

A predictive model integrating deep and radiomics features based on gadobenate dimeglumine-enhanced MRI for postoperative early recurrence of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is the most common liver cancer worldwide, and early recurrence of HCC after curative hepatic resection is indicative of poor prognoses. We aim to develop a predictive model for postoperative early recurrence of HCC based on deep and radiomics features from multi-phasic magnetic resonance imaging (MRI). A total of 472 HCC patients were included and divided into the training (n = 378) and validation (n = 94) cohorts in the retrospective study. We separately extracted radiomics features and deep features from eight phases of gadoxetic acid-enhanced MRI and utilized the least absolute shrinkage and selection operator logistic regression algorithm for feature selection and model construction. We integrated the selected two types of features into a combined model and established a radiomics model as well as a deep learning (DL) model for comparison. In the training and validation cohorts, the combined model demonstrated better performance for stratifying patients at high risk of early recurrence (AUC of 0.911 and 0.840, accuracy of 0.779 and 0.777, sensitivity of 0.927 and 0.769, specificity 0.720 and 0.779) than the radiomics model (AUC of 0.740 and 0.780) and the DL model (AUC of 0.887 and 0.813). The combined model integrating deep and radiomics features from multi-phasic MRI is efficient for noninvasively stratifying patients at high risk of early HCC recurrence after resection.

Time-Resolved Magnetic Resonance Angiography for Follow-Up of Treated Dural and Epidural Spinal Arteriovenous Fistula.

Spinal arteriovenous fistulas (AVFs) are uncommon vascular malformations of spinal dural and epidural vessels. Actually digital subtraction angiography (DSA) is the gold standard for diagnosis and follow-up. The aim of this study is to demonstrate the validity of the multiphasic magnetic resonance angiography (MRA) to identify recurrent/residual AVFs or their correct surgical and/or endovascular closure. A retrospective cases series with perimedullary venous plexus congestion due to spinal dural or epidural AVF was performed at our center from April 2014 to September 2019. After 1 month from treatment, the patients were subjected to time-resolved MRA and DSA to demonstrate recurrence or correct closure of AVFs. We collected a series of 26 matched time-resolved MRA and DSA in 20 patients who underwent an endovascular and/or surgical procedure. In our series, we reported five cases of recurrence. Time-resolved MRA detected six cases of recurrence, with 100% sensitivity and 95% specificity (p < 0.001). We used DSA as the standard reference. Time-resolved MRA is a valid tool in posttreatment follow-up to detect recurrent or residual AVFs. It has high sensitivity and specificity and may replace DSA.

Free-breathing contrast-enhanced multiphase MRI of the liver in patients with a high risk of breath-holding failure: comparison of compressed sensing-accelerated radial and Cartesian acquisition techniques.

Knowing the advantages and disadvantages of each magnetic resonance (MR) technique, would allow us to choose a sequence better suited in patients with a high risk of breath-holding failure. To compare the image quality of free-breathing contrast-enhanced multiphase MR imaging (MRI) using incoherent Cartesian k-space sampling combined with a motion-resolved compressed sensing reconstruction (XD-VIBE) and Golden-Angle Radial Sparse Parallel MRI (GRASP). A total of 67 patients were included. Overall image quality, motion artifacts, and liver edge sharpness on arterial and portal-venous phase were evaluated by two radiologists. We evaluated the signal intensity ratio between liver in the late arterial phase to aorta at peak enhancement and the detection rate of hypervascular lesions. Overall image quality, artifact, and liver edge sharpness scores of XD-VIBE and GRASP were not significantly different (P = 0.070-0.397). Four (reviewer 1, 12.1%) and seven patients (reviewer 2, 21.2%) received non-diagnostic quality in the XD-VIBE group whereas one patient (reviewer 2, 2.9%) received non-diagnostic quality in the GRASP group. The ratio between the aorta and liver signal for GRASP was significantly higher than that of XD-VIBE (0.32 ± 0.10 vs. 0.47 ± 0.13; P < 0.001). The hypervascular lesion detection rate of XD-VIBE (86.7%) was higher than that of GRASP (57.1%) in the arterial phase without a statistically significant difference (P = 0.081). Overall image quality of XD-VIBE and GRASP were not significantly different. More XD-VIBE examinations were rated non-diagnostic. On the other hand, the relative liver parenchymal enhancement to the aorta in the late arterial phase of GRASP was higher than that of XD-VIBE, which potentially leads to lower detectability of hypervascular lesions on arterial phase images.

Quantitative analysis of multiphase magnetic resonance images may assist prediction of histopathological grade of small hepatocellular carcinoma.

BackgroundThe aim of the study was to investigate whether preoperative quantitative analysis of multiphase magnetic resonance images may assist in predicting the pathological grade of small hepatocellular carcinoma (HCC).MethodsA total of 49 patients with small HCCs (≤3 cm) underwent multiphase magnetic resonance imaging (MRI) and were retrospectively reviewed. Routine unenhanced and post gadobenate dimeglumine (Gd-BOPTA)-enhanced MRI were preoperatively performed. Signal intensity (SI) was measured within the designated region of interest (ROI) including those of the lesion and paraspinous muscles. The lesion-to-paraspinous muscle relative contrast ratio (RCR) on T2-weighted (T2W) imaging, diffusion-weighted (DW) imaging, and dynamic phase Gd-BOPTA-enhanced T1W (T1-weighted) imaging were calculated, and statistical analysis was performed to determine the predictive power for the histological grade.ResultsIn all, 49 cases were included comprising 3 well-differentiated (WD) HCCs, 36 moderately differentiated (MD) HCCs, and 10 poorly differentiated (PD) HCCs. There was a negative correlation between the RCR and pathological grade of small HCC in the arterial phase [correlation coefficient (ρ)=−0.305, P<0.05]. However, there was no correlation between RCR in other phases and pathological grade (P>0.05 for all). There was also no correlation between tumor margin, tumor location, cystic/necrotic change, intratumoral fat, enhancement pattern, tumor capsule, tumor boundary or tumor size, and any of the differentiation categories (P>0.05 for all).ConclusionsThe lesion-to-paraspinous muscle RCR on arterial phase Gd-BOPTA-enhanced T1W imaging may be useful for the prediction of the histological characteristics of small HCC.

Magnetic resonance imaging biomarkers of cerebrospinal fluid tracer dynamics in idiopathic normal pressure hydrocephalus.

Disturbed clearance of toxic metabolites from the brain via cerebrospinal fluid is emerging as an important mechanism behind dementia and neurodegeneration. To this end, magnetic resonance imaging work-up of dementia diseases is largely focused on anatomical derangements of the brain. This study explores magnetic resonance imaging biomarkers of cerebrospinal fluid tracer dynamics in patients with the dementia subtype idiopathic normal pressure hydrocephalus and a cohort of reference subjects. All study participants underwent multi-phase magnetic resonance imaging up to 48 h after intrathecal administration of the contrast agent gadobutrol (0.5 ml, 1 mmol/ml), serving as cerebrospinal fluid tracer. Imaging biomarkers of cerebrospinal fluid tracer dynamics (i.e. ventricular reflux grades 0–4 and clearance) were compared with anatomical magnetic resonance imaging biomarkers of cerebrospinal fluid space anatomy (Evans’ index, callosal angle and disproportional enlargement of subarachnoid spaces hydrocephalus) and neurodegeneration (Schelten’s medial temporal atrophy scores, Fazeka’s scores and entorhinal cortex thickness). The imaging scores were also related to a pulsatile intracranial pressure score indicative of intracranial compliance. In shunt-responsive idiopathic normal pressure hydrocephalus, the imaging biomarkers demonstrated significantly altered cerebrospinal fluid tracer dynamics (ventricular reflux grades 3–4 and reduced clearance of tracer), deranged cerebrospinal fluid space anatomy and pronounced neurodegeneration. The altered MRI biomarkers were accompanied by pressure indices of impaired intracranial compliance. In conclusion, we present novel magnetic resonance imaging biomarkers characterizing idiopathic normal pressure hydrocephalus pathophysiology, namely measures of cerebrospinal fluid molecular redistribution and clearance, which add information to traditional imaging scores of cerebrospinal fluid space anatomy and neurodegeneration.

Effects of gadoxetic acid on image quality of arterial multiphase magnetic resonance imaging of liver: comparison study with gadoteric acid-enhanced MRI.

To compare the effects of gadoxetic acid and gadoteric acid on the image quality of single-breath-hold, triple (first, second, and third) arterial hepatic magnetic resonance imaging (MRI). Two hundred and eleven patients were divided into two groups according to the contrast materials used (gadoxetic acid, 108 patients and gadoteric acid, 103 patients). All 3.0-T MR examinations included triple arterial phase acquisition using the 4D enhanced T1-weighted high-resolution isotropic volume examination (eTHRIVE) keyhole technique. The image qualities of the pre-contrast and triple arterial phases were assessed in terms of image artifacts, sharpness of the intrahepatic vessel and liver edge, and overall image quality with a 5-point scale for qualitative analysis. The image quality of gadoxetic acid-enhanced liver MRI in the triple arterial phases was significantly degraded compared with that of gadoteric acid-enhanced liver MRI, although better image scores were observed in the pre-contrastimages in the gadoxetic acid group (P < 0.001). The overall image quality gradually improved from the first to the third arterial phases in both groups (P < 0.003). Intravenous gadoxetic acid could have a detrimental effect on image quality of triple arterial phase MRI with the 4D eTHRIVE Keyhole technique. The third arterial phase images had the best image qualities; thus, they could be used as key scans.

Continuous Hepatic Arterial Multiphase Magnetic Resonance Imaging During Free-Breathing.

The aim of this study was to evaluate the feasibility of a prototype volume-interpolated breath-hold examination (VIBE) sequence using compressed sensing (VIBECS) for rapid multiphase arterial magnetic resonance imaging (MRI) at different temporal resolution during free-breathing in comparison with a conventional breath-hold approach (VIBESTD). A total of 40 patients with liver malignancies were prospectively included in this study and underwent contrast-enhanced liver MRI at 1.5 T to evaluate the performance of VIBECS for rapid arterial multiphase imaging. An additional 40 patients examined with a VIBESTD were included serving as standard of reference. The VIBECS study cohort was subdivided into 2 groups (each n = 20). In both groups, VIBECS was continuously acquired for 60 seconds starting with the contrast agent administration (group A, temporal resolution 4 seconds; group B, temporal resolution 8 seconds). Subsequently, the time point with the subjectively best image quality was selected and defined as hepatic arterial dominant (HAD) phase. Overall image quality, lesion conspicuity, vessel contrast, and artifacts of HAD phase were assessed by 2 radiologists independently on a 5-point Likert scale (5 = excellent) and compared with arterial phase images of VIBESTD. In addition, signal attenuation/time curves of VIBECS were plotted for each patient to quantify the hepatic arterial enhancement. No patients were excluded and all HAD phases were reliably recorded in the investigated VIBECS cohort. Most commonly, HAD was observed at the ninth time point (36 seconds after intravenous contrast injection) in group A and at the fifth time point (40 seconds after intravenous contrast injection) in group B. Timing with VIBESTD was only adequate in 65% (26/40). Image quality, lesion conspicuity, and vessel contrast were good to excellent without significant differences between both VIBECS groups (P ≥ 0.2) and with significantly higher reading scores as compared with VIBESTD with respect to lesion conspicuity (P ≤ 0.006) and image quality (group B; P < 0.001). VIBECS showed reconstruction artifacts, which were significantly higher in group A (P = 0.001). Mean peak arterial enhancement was observed at the ninth time point (36 seconds) in group A and at the sixth (48 seconds) in group B. VIBECS allows for robust multiphase arterial imaging during free-breathing at high spatial and temporal resolution (preferably 8 seconds) with improved image quality and lesion conspicuity as compared with VIBESTD.

Assessment of multiphasic contrast-enhanced MR textures in differentiating small renal mass subtypes.

This study seeks to evaluate the use of quantitative texture parameters extracted from multiphasic contrast-enhanced magnetic resonance (MR) imaging in differentiating between benign and malignant masses (oncocytoma vs. clear cell and papillary RCC) and between common subtypes of renal cell carcinoma (clear cell vs. papillary RCC) in small renal masses (< 4cm). One-hundred and forty-two renal lesions (90 clear cell and 22 papillary RCCs; 30 oncocytomas) were identified in a cohort of 41 patients (18 men, 23 women: mean age, 52.8 ± 14.4years) who underwent preoperative multiphasic contrast-enhanced MR with four phases (unenhanced, arterial, venous, and delayed) between 2015 and 2016. In this study, texture features were extracted from entire cross-sectional tumoral region in three consecutive slices containing the largest cross-sectional area from each of the four phases. The change in imaging feature between precontrast imaging and each postcontrast phase was calculated. Data dimension reduction and feature selection were performed by conducting (1) pairwise Wilcoxon rank test followed by modified false discovery rate adjustment, and (2) Lasso regression. Multivariate modeling incorporating the selected features was performed using random forest classification method. Histogram imaging features were informative variables in differentiating between benign and malignant masses, while textures imaging features were of added value in differentiating between subtypes of RCCs. Papillary RCCs were distinguished from clear cell RCCs (sensitivity 65.5%, specificity 88%, and accuracy 77.9%), oncocytomas from clear cell RCCs (sensitivity 67.3%, specificity 88.9%, and accuracy 79.3%), and oncocytomas from papillary and clear cell RCCs (sensitivity 64.7%, specificity 85.9%, and accuracy 77.9%). A combination of histogram and texture imaging features on multiphasic MR can help differentiate histologic cell types in common small renal masses (< 4cm).

Diagnosis of Pancreatic Neuroendocrine Tumors.

Pancreatic neuroendocrine tumors (PNETs) are relatively rare; however, the incidence has increased over the last few decades. They are classified as functional or non-functional tumors according to the presence of associated clinical symptoms. The majority are non-functional tumors. For classification and staging, the World Health Organization 2010 classification system is the most commonly accepted. Chromogranin A is the most sensitive marker but has insufficient specificity. In general, PNETs are hypervascular tumors, and multiphasic contrast-enhanced computed tomography is considered the first choice for imaging study. Multiphasic magnetic resonance imaging can detect PNETs smaller than 2 cm and small liver metastasis compared with other modalities. Somatostatin receptor scintigraphy is often used in cases where functional PNETs are suspected. Positron emission tomography (PET) scan with 18F-fluorodeoxyglucose cannot visualize PNETs, but PET with 68-Ga DOTATATE can. Endoscopic ultrasonography can characterize smaller PNETs using contrast and confirm histology through fine needle aspiration or biopsy. In this article, we review the characteristics of grading systems and diagnostic modalities commonly used for PNETs.

Imaging Findings Within the First 12 Months of Hepatocellular Carcinoma Treated With Stereotactic Body Radiation Therapy

To correlate the imaging findings of treated hepatocellular carcinoma (HCC) after stereotactic body radiation therapy (SBRT) with explant pathology and alpha-fetoprotein (AFP) response. From 2007 to 2015, of 146 patients treated with liver SBRT for Barcelona Clinic Liver Cancer stage A hepatocellular carcinoma, 10 were identified with inclusion criteria and had regular interval follow-up magnetic resonance imaging/triple phase computed tomography and explant pathology or declining AFP values for radiology-pathology response correlation. Reference standards for successful response were >90% necrosis on explant pathology or pretreatment AFP >75ng/mL normalizing to <10ng/mL within 1year after SBRT without other treatment. Subjects were treated with 24 to 50Gy in 3 to 5 fractions. Multiphasic magnetic resonance imaging or computed tomography performed at 3, 6, 9, and 12months after SBRT was compared with pretreatment imaging by 2 expert radiologists. Descriptive statistics were calculated. There were 10 subjects with 10 treated HCCs, classified as 3 Organ Procurement and Transplantation Network (OPTN) 5a, 4 OPTN 5b, and 3 OPTN 5x. All had successfully treated HCCs, according to explant pathology or declining AFP. Four of 10 HCCs had persistent central arterial hyperenhancement 3 to 12months after SBRT; persistent wash-out was common up to 12months (9 of 10). Of 10 treated HCCs, 9 exhibited decreased size at 12months. Liver parenchyma adjacent to the lesion showed early (3-6months) hyperemia followed by late (6-12months) capsular retraction and delayed enhancement. No patient had a significant decline in liver function. In the absence of increasing size, persistent central arterial hyperenhancement and wash-out can occur within the first 12months after SBRT in successfully treated HCCs and may not represent residual viable tumor. Liver parenchyma adjacent to the treated lesion showed inflammation followed by fibrosis, without significant change in hepatic function. Until a radiologic signature of tumor control is determined, freedom from local progression seems to be the best measure of HCC control after SBRT.

Evolving management of insulinoma: Experience at a tertiary care centre.

Background & objectives:Since our previous study in 2006, several new modalities for localization of cause of endogenous hyperinsulinemic hypoglycaemia such as multiphasic computed tomography (CT), multiphasic magnetic resonance imaging (MRI), endoscopic ultrasound (EUS), intraoperative ultrasound, and intra-arterial calcium infusion with arterial stimulation venous sampling (ASVS) have become available. Therefore, to evaluate the relative usefulness of various imaging modalities to guide future management in terms of diagnosis and patient care, we analyzed presentation and management of patients of endogenous hyperinsulinemic hypoglycaemia.Methods:In this retrospective study, medical records of patients admitted with endogenous hyperinsulinemic hypoglycaemia were retrieved. Data pertaining to clinical features, diagnosis, imaging, surgery and patient outcome were extracted. The localization of insulinoma by preoperative imaging techniques was compared with the findings at surgery to assess the accuracy of localization.Results:Fasting hypoglycaemia was present in all, and post-prandial hypoglycaemia (plasma glucose ≤50 mg/dl within four hours of meal) in 25.8 per cent. Mean duration of symptoms before reaching a diagnosis of hyperinsulinemic hypoglycaemia was 3.9 years. Mean duration of provocative fast was 21.8 h (range 6-48 h). Among the currently used imaging modalities, the sensitivity of localizing tumour was 79.3 per cent for multiphasic CT, 85 per cent for multiphasic MRI and 95 per cent for EUS. EUS detected tumour missed by both CT and MRI. All, except one of the operated patients, were cured by surgery.Interpretation & conclusions:Our results suggest that patients with insulinoma have a varied presentation. Multiphasic contrast-enhanced MRI/CT scan, EUS and ASVS may be complimentary in pre-operative localization.

Can Stereotactic Body Radiotherapy Effectively Treat Hepatocellular Carcinoma?

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors' suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology, to patients seen in their own clinical practice.A 78-year-old woman with a past medical history of hepatitis C virus (HCV) presented on routine examination to her family doctor with abnormal liver function tests. She was referred for liver ultrasound, which detected a liver mass. Multiphasic magnetic resonance imaging (MRI) diagnosed liver cirrhosis and a segment 7/8 lesion measuring 4 cm, suspicious for a hepatocellular carcinoma (HCC), without evidence of portal hypertension. Child-Pugh (CP) score (ranging from 5 to 15) is a clinically relevant measure of synthetic liver function, based on international normalized ratio and albumin and bilirubin levels, as well as presence or absence of ascites and encephalopathy. A score of A5 or 6 is associated with better postoperative survival compared with CP B7 to 9 or CP C10 to 15, in which surgery is contraindicated. Her CP score was A6, based on a low albumin of 34 g/L. Platelets were slightly depressed at 121,000 μL, and alpha-fetoprotein level was 89 μg/L. She had not received treatment of her HCV because of her age and low viral load. She does not drink alcohol. Clinically the patient had an Eastern Cooperative Oncology Group performance status (PS) of 1, no stigmata of chronic liver disease, and no ascites or encephalopathy or other associated clinical symptoms. An HCC multidisciplinary cancer conference recommended surgical resection. The patient was taken to the operating room for a planned liver nonanatomic wedge resection. At the time of laparotomy, extensive cirrhosis was found and resection was abandoned because of the high risk of liver failure. A biopsy was not obtained, as the tumor had classic arterial enhancement and washout on venous and delayed-phase computed tomography (CT) imaging, which is diagnostic for HCC. After laparotomy, the patient developed liver insufficiency manifested by new ascites and peripheral edema, treated with diuretics, a low-salt diet, and fluid restriction. She was discharged home after a week and referred for a radiation oncology opinion. Three months after laparotomy, her liver function had recovered, with resolution of her ascites and PS of 2. It was decided to proceed with nonsurgical local therapy to the liver mass with curative intent.

Irreversible Electroporation in Patients with Hepatocellular Carcinoma: Immediate versus Delayed Findings at MR Imaging.

To assess the postprocedure findings of irreversible electroporation (IRE) in patients with hepatocellular carcinoma (HCC) at magnetic resonance (MR) imaging. This retrospective study was Institutional Review Board approved, and informed consent was waived. Twenty patients with HCC were treated with IRE over a 2.5-year period. The median patient age was 62 years, and 75% of patients had cirrhosis with a Child-Pugh score of A. The median tumor diameter was 2.0 cm (range, 1.0-3.3 cm). Contrast material-enhanced multiphase MR imaging was performed on postprocedure days 1 and 30 and every 90 days thereafter. Ablation zone sizes and signal intensities were compared between each time point for both T1- and T2-weighted images. Trends in signal intensity and tumor dimensions over time were quantified by using generalized linear models. MR imaging appearances of treated tumors include a zone of peripheral enhancement with centripetal filling on delayed contrast-enhanced images. Compared with postprocedure day 1, every 90 days there is a decrease of 28.9% (mean, axis) in the size of the enhancing ablation zone. Over time, there is a trend toward decreasing signal intensity in the peripheral ablation zone on both T2-weighted (P = .01) and contrast-enhanced T1-weighted (P < .08) images. Conversely, the tumor itself typically has increased signal intensity on the same sequences. IRE of HCC results in a large region of enhancement on immediate postprocedure MR images that, over time, involutes and is associated with decreasing signal intensity of the peripheral ablation zone. This phenomenon may represent resolution of the reversible penumbra.

Multiphase contrast-enhanced magnetic resonance imaging features of Bacillus Calmette-Guérin-induced granulomatous prostatitis in five patients.

ObjectiveTo evaluate the multiphase contrast-enhanced magnetic resonance (MR) imaging features of Bacillus Calmette-Guérin (BCG)-induced granulomatous prostatitis (GP).Materials and MethodsMagnetic resonance images obtained from five patients with histopathologically proven BCG-induced GP were retrospectively analyzed for tumor location, size, signal intensity on T2-weighted images (T2WI) and diffusion-weighted images (DWI), apparent diffusion coefficient (ADC) value, and appearance on gadolinium-enhanced multiphase images. MR imaging findings were compared with histopathological findings.ResultsBacillus Calmette-Guérin-induced GP (size range, 9-40 mm; mean, 21.2 mm) were identified in the peripheral zone in all patients. The T2WI showed lower signal intensity compared with the normal peripheral zone. The DWIs demonstrated high signal intensity and low ADC values (range, 0.44-0.68 × 10-3 mm2/sec; mean, 0.56 × 10-3 mm2/sec), which corresponded to GP. Gadolinium-enhanced multiphase MR imaging performed in five patients showed early and prolonged ring enhancement in all cases of GP. Granulomatous tissues with central caseation necrosis were identified histologically, which corresponded to ring enhancement and a central low intensity area on gadolinium-enhanced MR imaging. The findings on T2WI, DWI, and gadolinium-enhanced images became gradually obscured with time.ConclusionBacillus Calmette-Guérin-induced GP demonstrates early and prolonged ring enhancement on gadolinium-enhanced MR imaging which might be a key finding to differentiate it from prostate cancer.

Evaluation of renal blood flow using multi-phase echo-planar magnetic resonance imaging and signal targeting with alternating radiofrequency (EPISTAR) in 3-T magnetic resonance imaging

Most arterial spin labeling techniques apply the constant post-labeling delay time after the blood-labeling time point on the target artery. As the hemodynamic status cannot be estimated in each patient, quantitative values of the blood flow may not be accurate. To overcome this problem, we performed renal perfusion imaging of human kidneys using multi-phase echo-planar magnetic resonance imaging and signal targeting with an alternating radiofrequency (EPISTAR) sequence at 3-T magnetic resonance imaging. Multi-phase EPISTAR obtained 17 phases every 100 ms between 250 and 1850 ms from the arterial-labeling time point. The highest signal-intensity image obtained using multi-phase images was applied to renal blood flow (RBF) calculations. In five healthy volunteers, the mean cortical RBF was 286.6 ± 48.7 mL/100 g/min. This value was not significantly different from those in four previous studies. This technique was more useful than previous studies, in that multi-phase images could confirm the hemodynamic status on RBF calculations.