Evaluation of Brain Tumors Using Amide Proton Transfer Imaging: A Comparison of Normal Amide Proton Transfer Signal With Abnormal Amide Proton Transfer Signal Value.

OBJECTIVE: The aim of the study was to evaluate the relationship of amide proton transfer (APT) signal characteristics in brain tumors and uninvolved brain tissue for patients with glioblastoma and those with brain metastases. METHODS: Using the mDIXON 3D-APT sequence of the fast spin echo method, an APT image was obtained. The mean APT signal values of tumor core, peritumor edema, ipsilateral normal-appearing white matter (INAWM), and contralateral normal white matter (CNAWM) were obtained and compared between glioblastoma and brain metastases. Receiver operating characteristic curves were used to evaluate parameters for distinguishing between glioblastoma and brain metastases. In addition, the difference and change rate in APT signal values between tumor core and peritumoral edema (PE) and CNAWM were evaluated, respectively. RESULTS: The APT signal values of glioblastoma were the highest in tumor core (3.41% ± 0.49%), followed by PE (2.24% ± 0.29%), INAWM (1.35% ± 0.15%), and CNAWM (1.26% ± 0.12%, P < 0.001). The APT signal value of brain metastases was the highest in tumor core (2.74% ± 0.34%), followed by PE (1.86% ± 0.35%), INAWM (1.17% ± 0.13%), and CNAWM (1.2% ± 0.09%, P < 0.01). The APT change rate (between PE and CNAWM) was not significantly different at 78% and 56% for glioblastoma and brain metastases, respectively ( P > 0.05). CONCLUSIONS: Performing APT imaging under the same parameters used in this study may aid in the identification of brain tumors.

Quantitative Analysis of Mobile Proteins in Normal Brain Tissue by Amide Proton Transfer Imaging: Age Dependence and Sex Differences.

PURPOSE: The aims of this study were to evaluate the relationship between age change and amide proton transfer (APT) signal in each region of the whole brain and to derive the standard value of APT signal in each brain region of normal adults. MATERIALS AND METHODS: Using the mDIXON 3-dimensional-APT sequence of the fast spin echo method, an APT image was obtained. In total, 60 patients (mean age, 49.8 ± 16.9 years) with no abnormal findings on magnetic resonance imaging data were included. For image analysis, registration parameters were created using the FMRIB Software Library 5.0.11, and then a region of interest was set in the Montreal Neurological Institute structural atlas for analysis. Statistical analyses were performed using the age-dependent and sex differences in APT signals from each brain region. RESULTS: No significant correlation was seen between APT signal and age and sex in all brain regions. CONCLUSION: Under the APT imaging parameter conditions used in this study, local brain APT signals in healthy adults are independent of age and sex.

Early postmortem volume reduction of adrenal gland: initial longitudinal computed tomographic study.

We aimed to confirm whether postmortem adrenal volumetric changes occur by measuring adrenal volumes on computed tomography (CT). Fifty-five adrenal glands from 28 subjects who died were included. All subjects underwent antemortem CT (AMCT) and postmortem CT (PMCT) within 94-1,191 min after death, followed by conventional autopsy. CT volumetry was performed using freely-available software. Differences between AMCT and PMCT adrenal volumes were evaluated statistically along with differences in the degree of volume change, elapsed time to PMCT, and presence of underlying malignant disease. The mean volume of the right adrenal gland decreased from 3.8 cm(3) on AMCT to 2.6 cm(3) on PMCT (P < 0.001); the left adrenal gland decreased from 4.2 cm(3) on AMCT to 3.1 cm(3) on PMCT (P < 0.001). Conventional autopsy revealed decreased intracellular lipid components in portions of the adrenal glands. No correlation between the adrenal gland reduction rate and the elapsed time from AMCT to death or from death to PMCT was observed (P = 0.99 and 0.79; P = 0.28 and 0.59 for the right and left adrenal glands, respectively). Significant differences in both the bilateral adrenal gland reduction rates and underlying malignant disease were found for the left adrenal gland (P = 0.015), but not for the right (P = 0.74). Adrenal volume reduction was observed on PMCT compared to AMCT. This highlights the need to further elucidate the mechanism of adrenal shrinkage during the agonal stage and after death. This may be explained by pathological findings of intracellular lipid depletion.

Fluid in the airway of nontraumatic death on postmortem computed tomography: relationship with pleural effusion and postmortem elapsed time.

To evaluate radiographic features of endotracheal/endobronchial fluid in the airway (FA) observed on postmortem computed tomography (PMCT). We studied 164 subjects who died at our hospital between April 2009 and September 2012. Fluid in the airway was considered positive when fluid was identified in the lumen of 1 of the 2 main bronchi in continuity with a segmental bronchus. Pleural effusion and atelectasis/consolidation of the lung lower lobes were also evaluated. Fluid in the airway was observed in 60 (71%) of 84 subjects with unilateral or bilateral pleural effusion, and in 44 (55%) of 80 subjects without pleural effusion (P = 0.029). Of the latter, 41 (93%) had atelectasis/consolidation of the lower lung lobes. Among subjects without pleural effusion, average times after death to PMCT of subjects with and without FA were 501 and 314 minutes, respectively (P = 0.01). Time-course analysis showed that cases with FA on PMCT largely correlated with time after death (R = 0.7966). Fluid in the airway is frequently observed on PMCT in subjects with pleural effusion or atelectasis/consolidation of the lung. No FA in subjects without pleural effusion correlated to shorter times after death. In addition, FA frequency on PMCT increased over time after death.

Visualization of bile movement using MRI spin-labeling technique: preliminary results.

OBJECTIVE: The purpose of this article is to noninvasively visualize intrabiliary bile movement using an MRI spin-labeling technique and administration of water, full-fat milk, and negative contrast agent as stimuli for bile excretion. SUBJECTS AND METHODS: Six healthy volunteers underwent three studies with each of three oral liquid agents (water, full-fat milk, and manganese chloride solution) for a total of 18 MRI studies. Oblique-coronal T2-weighted images of the common bile duct were acquired at an inversion time of 1500 milliseconds after pulse labeling using a spin-labeling technique with an inversion pulse, repeated at intervals of 22 seconds. Bile flow rate was measured before and for 50 minutes after administration of the oral liquid agents, and its correlation with the change in gallbladder volume was assessed. RESULTS: Both anterograde and retrograde intermittent bile movements were successfully visualized in the common bile duct. The summation of excreted bile volume calculated from spin-labeled images correlated significantly with a decrease in gallbladder volume (p = 0.011). Milk stimulated significantly prolonged bile flow; flow was momentary with manganese chloride and mild with water; however, gallbladder volume decreased only in milk studies (p = 0.003). Biliary flow early after oral intake correlated significantly with gallbladder contractility at 50 minutes after oral intake (p = 0.049). CONCLUSION: A new method for visualizing intrabiliary bile movement in semi-real time (22-second time resolution) using an MRI spin-labeling technique was proposed. Bile was shown to be excreted in a to-and-fro type of movement. Administration of water and negative contrast agent may induce temporary bile excretion.

Santorinicele without pancreas divisum pathophysiology: initial clinical and radiographic investigations.

BACKGROUND: Only one case of santorinicele without pancreas divisum pathophysiology (SWOPP) was previously reported. The purpose of the study was to determine the gross prevalence of SWOPP and santorinicele with pancreas divisum (SWPD) in community and patient populations, and investigate their clinical and radiographic features. METHODS: This cross-sectional study was performed at a tertiary referral centre. The Patient group comprised 2035 consecutive patients enrolled in the study who underwent magnetic resonance cholangiopancreatography (MRCP) studies. The Community group comprised 2905 consecutive subjects who participated in our whole-body medical check-up program that routinely includes MRCP studies. SWOPP was diagnosed when a saccular dilatation of the terminal portion of the dorsal pancreatic duct was observed unaccompanied by pancreas divisum or dominant dorsal duct. The prevalence of SWOPP and SWPD, and the clinical and radiological features were assessed in each group. RESULTS: Five cases of SWOPP were found in the Patient group (age range, 67-85 years; mean age, 73.6 years) (5/2035 = 0.25%; 95% confidence interval, 0.07-0.57); there were no cases of SWOPP in the Community group (0/2905 = 0.00%; 95% confidence interval, 0.00-0.10) (P = 0.01). Previous history of pancreatitis (4/5) and chronic pancreatitis (3/5) was more common in patients with SWOPP than in other subjects in the Patient or Community groups (both P < 0.05). Two cases of SWOPP were accompanied by reverse-Z type meandering main pancreatic duct. Six cases of SWPD were found. These cases were asymptomatic in 4/6, had a larger santorinicele (6.9 mm) than SWOPP patients (4.5 mm; P = 0.02), and were not associated with pancreatitis (0/6). CONCLUSIONS: The second to sixth reported cases of SWOPP were presented. SWOPP is a relatively rare condition found mostly in patients suffering pancreatitis, especially chronic pancreatitis, and may be an acquired condition. Santorinicele is not always accompanied by pancreas divisum.

Pancreas divisum as a predisposing factor for chronic and recurrent idiopathic pancreatitis: initial in vivo survey.

BACKGROUND: It is a controversial issue whether pancreas divisum (PD) induces pancreatitis. All previous studies have investigated this issue based on endoscopic procedures, which inevitably involve a selection bias. OBJECTIVES: To determine the unbiased prevalence rate of PD in a community population and to investigate the effect of PD on idiopathic pancreatitis using a non-invasive magnetic resonance (MR) technique. DESIGN: Cross-sectional study. PATIENTS: The study enrolled 504 subjects from the community who participated in the medical check-up programme and 46 patients with idiopathic pancreatitis (8 acute, 23 chronic, 15 recurrent) extracted from 70,122 consecutive MR studies performed at an academic tertiary care hospital. INTERVENTIONS: All subjects underwent magnetic resonance (MR) scanning and medical examination. MAIN OUTCOME MEASURES: Statistical comparison between subjects from the community and patients with idiopathic pancreatitis was made for the rate of PD (and its subtypes: classical PD, PD with absent ventral duct, and incomplete PD), MR findings, and clinical features. RESULTS: Multiple logistic regression analysis revealed PD as a significant factor that induces pancreatitis (OR 23.4; p<0.0001). The PD rate was significantly higher for all/chronic/recurrent idiopathic pancreatitis patients (35%/43%/33%; p<0.001 for all) than for subjects in the community group (2.6%), but was not higher for acute pancreatitis (13%; p=0.357). All PD subtypes were indicated to induce idiopathic pancreatitis but showed different associations with each onset type of pancreatitis. CONCLUSIONS: This is the first study to describe the prevalence of PD and PD subtypes in a community population and their association with idiopathic pancreatitis in vivo based on the findings of non-invasive MR and with minimal selection bias. It is concluded that PD should be considered a predisposing factor for chronic and recurrent pancreatitis.

Massive splenic infarction and splenic venous thrombosis observed in a patient with acute splenic syndrome of sickle cell traits on contrast-enhanced thin-slice computed tomography.

We report a case of splenic infarction in a patient with sickle cell traits (SCT), focusing on the computed tomography (CT) findings. The patient was an African-American man in his twenties with no past medical history who experienced sudden left upper quadrant pain while climbing a mountain (over 3000 m above sea level). Dynamic contrast-enhanced CT revealed massive non-segmental splenic infarction accompanied with nodule-like preserved splenic tissue. The region of splenic infarction did not coincide with the arterial vascular territory and differed from the features of infarction caused by large arterial embolism. In addition, thrombotic occlusion of the distal splenic vein was depicted on plain and contrast-enhanced thin-slice CT images. Early-phase contrast-enhanced images also showed inhomogeneous enhancement of the hepatic parenchyma. The patient's symptoms improved with conservative therapy. A hemoglobin electrophoresis test confirmed the diagnosis of SCT. SCT is usually asymptomatic, but hypoxic environments may induce acute splenic syndrome, which is commonly manifested as splenic infarction. We observed splenic venous thrombosis and inhomogeneous hepatic parenchymal enhancement in addition to a huge splenic infarction in our patient. To the best of our knowledge, this is the first report describing the specific imaging findings, particularly splenic venous thrombosis and inhomogeneous hepatic parenchymal enhancement, of acute splenic syndrome in a patient with previously undiagnosed SCT. These findings demonstrate the pathophysiology of SCT, and may help with the diagnosis of this disease.

Clinical value of 3D T2*-weighted imaging with multi-echo acquisition: comparison with conventional 2D T2*-weighted imaging and 3D phase-sensitive MR imaging.

Susceptibility-weighted angiography (SWAN) is a state-of-the-art 3-dimensional (3D) T2*-weighted imaging (T2*WI) technique with multiple echo acquisitions, but its clinical utility remains to be determined. We compared the utility of susceptibility-weighting sequences among SWAN, 3D phase-sensitive magnetic resonance (MR) imaging (PSI), and conventional 2-dimensional (2D) T2*WI in routine clinical practice. Our results indicate that SWAN can achieve susceptibility weighting more effectively than conventional 2D T2*WI and as effectively as PSI and requires a much shorter scan time than PSI.

Meandering main pancreatic duct as a relevant factor to the onset of idiopathic recurrent acute pancreatitis.

BACKGROUND: Meandering main pancreatic duct (MMPD), which comprises loop type and reverse-Z type main pancreatic duct (MPD), has long been discussed its relation to pancreatitis. However, no previous study has investigated its clinical significance. We aimed to determine the non-biased prevalence and the effect of MMPD on idiopathic pancreatitis using non-invasive magnetic resonance (MR) technique. METHODS AND FINDINGS: A cross-sectional study performed in a tertiary referral center. The study enrolled 504 subjects from the community and 30 patients with idiopathic pancreatitis (7 acute, 13 chronic, and 10 recurrent acute). All subjects underwent MR scanning and medical examination. MMPD was diagnosed when the MPD in the head of pancreas formed two or more extrema in the horizontal direction on coronal images of MR cholangiopancreatography, making a loop or a reverse-Z shaped hairpin curves and not accompanied by other pancreatic ductal anomaly. Statistical comparison was made among groups on the rate of MMPD including loop and reverse-Z subtypes, MR findings, and clinical features. The rate of MMPD was significantly higher for all idiopathic pancreatitis/idiopathic recurrent acute pancreatitis (RAP) (20%/40%; P<0.001/0.0001; odds ratio (OR), 11.1/29.0) than in the community (2.2%) but was not higher for acute/chronic pancreatitis (14%/8%; P = 0.154/0.266). Multiple logistic regression analysis revealed MMPD to be a significant factor that induces pancreatitis/RAP (P<0.0001/0.0001; OR, 4.01/26.2). Loop/reverse-Z subtypes were found more frequently in idiopathic RAP subgroup (20%/20%; P = 0.009/0.007; OR, 20.2/24.2) than in the community (1.2%/1.0%). The other clinical and radiographic features were shown not associated with the onset of pancreatitis. CONCLUSIONS: MMPD is a common anatomical variant and might be a relevant factor to the onset of idiopathic RAP.

Postmortem changes of the thyroid on computed tomography.

OBJECTIVE: To evaluate the radiographic features of the thyroid on postmortem computed tomography (PMCT). METHODS: We studied the bodies of 32 subjects who had been treated and subsequently died in our tertiary care hospital between April and December 2009. The thyroids were imaged by antemortem computed tomography (AMCT), PMCT, and examined by conventional autopsy. Differences between the radiographic features of the thyroid on AMCT and PMCT, and time since AMCT were evaluated statistically. RESULTS: CT values of the thyroid decreased after death with an average of 114.2 Hounsfield Units (HUs) on AMCT vs. 107.7HU on PMCT (paired t-test, P=0.023). There was no correlation between the elapsed time from AMCT and differences of CT values of the thyroid on AMCT and PMCT (Spearman's rank correlation test, P>0.05). CONCLUSION: We showed that CT values of the thyroid decreased after death.

Intravascular gas distribution in the upper abdomen of non-traumatic in-hospital death cases on postmortem computed tomography.

OBJECTIVES: To investigate the occurrence of intravascular gas in the liver, kidneys, spleen, and pancreas by postmortem computed tomography (PMCT) in cases of non-traumatic in-hospital deaths and elucidate the relationship between the PMCT data and clinical information or autopsy results. METHODS: The study included 45 cadavers of patients who died while receiving treatment in our academic tertiary-care hospital between April and December 2009. All subjects underwent PMCT and conventional autopsy. The appearance of postmortem gas in the liver, kidney, spleen, and pancreas was assessed using PMCT and scored using a subjective scale (liver, L0-L3; kidney, K0-K2; spleen, S0-S1; and pancreas, P0-P1), and the distribution of gases in the vessels of the liver (arteries, veins, and portal veins) was analyzed. The relationship between the gas score and time elapsed since death, cardiopulmonary resuscitation (CPR), administration of antibiotics, a history of bacteremia, or cause of death was assessed statistically. RESULTS: Positive correlations were found between administration of CPR and liver and kidney gas scores (P=0.008 and 0.002, respectively), but not with spleen and pancreas gas (P=0.291 and 0.535, respectively). No significant relationship between distribution of gas in the vessels of the liver and CPR was found. No other significant correlations between gas and any of the other parameters described above were found. While significant correlations were detected in no-CPR cases between liver gas, kidney gas, spleen gas, and pancreas gas (P<0.001 for all six combinations), no correlation between these parameters was detected in the CPR cases. CONCLUSIONS: The present study was the first statistical analysis of intravascular gas in the liver, kidneys, spleen, and pancreas by using PMCT in non-traumatic in-hospital death cases. The results showed that PMCT in the presence and absence of CPR reveals differences in intraorgan gas distribution. In addition, the detection of intraorgan gas on PMCT cannot be used to predict time elapsed since death, and it is not affected by the administration of antibiotics, a history of bacteremia, and cause of death. Awareness of these postmortem changes is important for the accurate interpretation of PMCT results.

Hypostasis in the heart and great vessels of non-traumatic in-hospital death cases on postmortem computed tomography: relationship to antemortem blood tests.

OBJECTIVES: The purpose of this study was to investigate hypostasis in the heart and great vessels (HHGV) by postmortem computed tomography (PMCT) in cases of non-traumatic in-hospital deaths and to analyze relationships between clarity of HHGV and antemortem blood markers. MATERIAL AND METHODS: The study included 31 cadavers of patients who died while receiving treatment in our academic tertiary-care hospital between April and December 2009. Antemortem blood tests including both hematological and blood coagulation markers were performed within 48h before death, and PMCT and conventional autopsies were performed. The findings of HHGV were assessed in the following six locations: the superior vena cava, right atrium, right ventricle, thoracic aorta, left atrium, and left ventricle. The clarity of HHGV on PMCT was divided into two groups using attenuation of the left ventricular wall as a reference: no/obscure HHGV group and clear HHGV group. The relationships between clarity of HHGV and six blood markers [red blood cell (RBC) count, hemoglobin (Hb), hematocrit (Ht), prothrombin percentage activity (PT%), activated partial thromboplastin time (aPTT), and fibrinogen] were evaluated statistically. RESULTS: We observed no/obscure HHGV in 14 patients (45%) and clear HHGV in 17 patients (55%). The level of fibrinogen in clear HHGV group was significantly higher than in no/obscure HHGV group (P=0.029). No relationships were found between clarity of HHGV and other five blood markers. CONCLUSION: HHGV is a common PMCT finding. Clear HHGV on PMCT was related to higher level of fibrinogen in non-traumatic in-hospital death cases.

Retroportal main pancreatic duct with circumportal pancreas: radiographic visualization.

PURPOSE: The aim of this study was to investigate the imaging findings of retroportal main pancreatic duct (RMPD), a rare anomaly of the pancreas, and circumportal pancreas (CP) on computed tomography (CT) and magnetic resonance (MR) imaging. We also reviewed the previous literature and discussed its best imaging method, etiology and clinical importance. METHODS: This work is a retrospective study. Two cases of RMPD were enrolled. The imaging findings of RMPD and CP were reviewed among the various CT and MR images obtained. Differences in visualization among the scans were evaluated using a four-stage model. RESULTS: RMPD was always accompanied by CP. RMPD was detectable on contrast-enhanced CT but not on noncontrasted CT. RMPD was shown most clearly on arterial, portal and late phases of contrast-enhanced CT, contrast-enhanced fat-suppressed T1-weighted images and fat-suppressed T2-weighted images. CP was much easier to detect than RMPD and could be identified even on noncontrasted images. CONCLUSIONS: We described the fourth and the fifth reported cases of RMPD. This is the first study to describe its MR imaging findings. CP was always present in cases of RMPD and was easily detectable on tomographic images. When radiologists or surgeons notice CP, it is necessary to pay attention to the course of the main pancreatic duct, particularly preoperatively to avoid surgical complications. It should be noted that these anomalies are undetectable on projection images.