Jianping Lu

Discriminating cancer from noncancer tissue in the prostate by 3-dimensional proton magnetic resonance spectroscopic imaging: a prospective multicenter validation study.

Objectives:A prospective multicenter validation of the ability of 1H magnetic resonance spectroscopic imaging (MRSI) to distinguish cancer from noncancer tissues throughout the prostate with histopathology of the resected organ as the standard of reference. Materials and Methods:Institutional review board approval was obtained for all centers and all participating patients and volunteers provided written informed consent. Ninety-nine patients and 10 age-matched volunteers from 8 participating centers underwent magnetic resonance imaging and 3-dimensional MRSI with an endorectal coil at 1.5 T. Selected MRSI voxels were assigned to the peripheral zone (PZ), the central gland (CG), the periurethral area, and cancer tissue. Signal ratios of choline + creatine to citrate (CC/C) in spectra of these voxels were automatically calculated. Receiver operating characteristic curves were constructed to assess the accuracy by which this ratio can discriminate cancer from noncancer tissue. Results:A total of 70% of voxels in noncancer tissue and 90% of voxels in cancer tissue passed the quality check of the automatically fitted spectra. The median CC/C was significantly different between any noncancer and cancer tissue (P < 0.0001), but not between the different contributing centers. CC/C increased with cancer focus size (P = 0.0008) and certainty of voxel mapping to histopathologic cancer site (P < 0.0001). The area under the receiver operating characteristic curve for discriminating voxels of cancer tissue from noncancer tissue was 0.88 (confidence interval: 0.84–0.92) in the PZ and 0.76 (confidence interval: 0.71–0.81) in the CG. Conclusions:In patients with prostate cancer, recruited from different institutions, 3-dimensional MRSI is demonstrated to be a robust and quantitative technique, producing significantly different CC/C values for cancer compared with noncancer tissue for both the CG and the PZ.

MR Angiography and Imaging for the Evaluation of Middle Cerebral Artery Atherosclerotic Disease

SUMMARY: Intracranial atherosclerotic disease may constitute the most common cause of ischemic stroke worldwide; yet, in the developed world, imaging research has largely focused on extracranial atherosclerosis. Many studies in populations of Asian, African, and Hispanic descent demonstrate the preponderance of intracranial stenosis compared with carotid stenosis. This review examines the clinical presentations of MCA atherosclerosis and stenosis and the use of noninvasive MR imaging in the assessment of intracranial vasculature. MRA is a well-validated technique that offers great advantage over traditional angiography. Advances in high-resolution MR imaging of MCA stenosis have the potential to yield excellent visualization of plaque. Future developments in high-resolution MR imaging to depict intracranial atherosclerosis are explored in this review; these advances will guide endovascular therapy and the comparison of novel interventions.

In vivo MRI-based 3D Mechanical Stress–Strain Profiles of Carotid Plaques with Juxtaluminal Plaque Haemorrhage: An Exploratory Study for the Mechanism of Subsequent Cerebrovascular Events

OBJECTIVES Atherosclerotic plaque features, such as fibrous cap erosion, ulceration and rupture and presence of haemorrhage in carotid plaque are two important characteristics associated with subsequent cerebrovascular events and juxtaluminal haemorrhage/thrombus (JLH/T) indicates these two high-risk characteristics. This study aims to investigate the association between JLH/T and subsequent events in patients suffering from transient ischaemic attack (TIA). Three-dimensional mechanical analysis was employed to represent the critical mechanical stress (P-CStress) and stretch (P-CStretch) within the plaque. METHODS Fifty TIA patients with mild-to-moderate carotid stenosis (30-69%) underwent high-resolution magnetic resonance imaging (MRI) within 72 h of the acute event and eight were excluded from the analysis due to various reasons. A total of 21 patients were found to have JLH/T in the carotid plaque and 21 did not (N-JLH/T). During a 2-year follow-up period, 11 (52.4%) patients in the JLH/T group experienced recurrent events and none in the N-JLH/T group. Three-dimensional plaque structure was reconstructed based on the in vivo MRI for the mechanical analysis. RESULTS P-CStress of both groups was comparable (N-JLH/T: 174.45 ± 63.96 kPa vs. JLH/T: 212.60 ± 89.54 kPa; p = 0.120), but P-CStretch of JLH/T was significantly bigger than that of N-JLH/T (N-JLH/T: 1.21 ± 0.08 vs. JLH/T: 2.10 ± 0.53; p < 0.0001). Moreover, there were much bigger variations in stress and stretch of the JLH/T group during one cardiac cycle than in those of N-JLH/T group. CONCLUSIONS In vivo MRI-depicted JLH/T might be a high risk factor initiating recurrent events, as big deformation appearing around the rupture site might prevent healing and tear the haemorrhage/thrombus away from the host structure and prompt further thrombo-embolic events.

High resolution diffusion weighted magnetic resonance imaging of the pancreas using reduced field of view single-shot echo-planar imaging at 3 T

Diffusion weighted magnetic resonance imaging (DWI) has been mostly acquired using single-shot echo-planar imaging (ss EPI) to minimize motion induced artifacts. The spatial resolution, however, is inherently limited in ss EPI especially for abdominal imaging, even with the advances in parallel imaging. A novel method of reduced Field of View ss EPI (rFOV ss EPI) has achieved high resolution DWI in human carotid artery, spinal cord with reduced blurring and higher spatial resolution than conventional ss EPI, but it has not been used to pancreas imaging. In the work, comparisons between the full FOV ss-DW EPI and rFOV ss-DW EPI in image qualities and ADC values of pancreatic tumors and normal pancreatic tissues were performed to demonstrate the feasibility of pancreatic high resolution rFOV DWI. There were no significant differences in the mean ADC values between full FOV DWI and rFOV DWI for the 17 subjects using b=600s/mm(2) (P=0.962). However, subjective scores of image quality was significantly higher at rFOV ss DWI (P=0.008 and 0.000 for b-value=0s/mm(2) and 600s/mm(2) respectively). The spatial resolution of DWI for pancreas was increased by a factor of over 2.0 (from almost 3.0mm/pixel to 1.25mm/pixel) using rFOV ss EPI technique. Reduced FOV ss EPI can provide good DW images and is promising to benefit applications for pancreatic diseases.

18F-FDG PET/CT in Differentiating Acute Tuberculous From Idiopathic Pericarditis: Preliminary Study

Purpose The aim of this study was to evaluate retrospectively the diagnostic capability of 18F-FDG PET/CT in differentiating acute tuberculous from idiopathic pericarditis. Methods FDG PET/CT findings were reviewed in 15 patients with acute tuberculous (n = 5) or idiopathic pericarditis (n = 10). The maximal thickness and SUVmax of the pericardium and the number, size, and SUVmax of the mediastinal and supraclavicular lymph nodes with increased FDG uptake were measured. Results All patients had small-to-large amount of pericardial effusion. The patients with acute tuberculous pericarditis (n = 5) showed diffuse (n = 3) or multifocal (n = 2) FDG uptake in the pericardia. The patients with acute idiopathic pericarditis (n = 10) showed diffuse (n = 6) or regional (n = 4) FDG uptake in the pericardia. The mean (SD) pericardial thickness and SUVmax of acute tuberculous pericarditis were significantly higher than those of acute idiopathic pericarditis (5.1 [1.0] vs 3.4 [0.9], P < 0.05; 13.5 [3.9] vs 3.0 [0.7], P < 0.05, respectively). A total of 69 mediastinal and supraclavicular lymph nodes with increased FDG uptake were observed in all 15 patients (44 in patients with acute tuberculous pericarditis and 25 in patients with acute idiopathic pericarditis). The mean (SD) SUVmax of mediastinal and supraclavicular lymph nodes of acute tuberculous pericarditis (5.3 [1.8]) was significantly higher than that of acute idiopathic pericarditis (2.8 [0.6], P < 0.05). There was no significant difference in the mean size of the mediastinal and supraclavicular lymph nodes between acute tuberculous and idiopathic pericarditis. Conclusions The degrees of FDG uptake in the pericardium and the mediastinal and supraclavicular lymph nodes are useful for differentiating acute tuberculous from idiopathic pericarditis. Familiarity with the FDG uptake patterns of acute tuberculous and idiopathic pericarditis may be helpful for successful (especially timely) diagnosis and treatment.

MRI and FDG PET/CT findings of hepatic epithelioid hemangioendothelioma.

Purpose The aim of this study was to evaluate retrospectively magnetic resonance imaging (MRI) and 18F fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) findings of hepatic epithelioid hemangioendothelioma (HEH). Patients and Methods MRI and FDG PET/CT findings were reviewed in 6 patients with HEH confirmed by pathology. All patients underwent magnetic resonance (MR) examination. Early PET/CT scans were performed 1 hour after FDG injection in all 6 patients. After an interval of 1 hour, delayed PET/CT scans were performed in 4 patients. Results A total of 60 lesions were detected in all 6 patients. MRI features of HEH included multifocal hepatic disease, predominantly subcapsular location, coalescence of lesions, and capsular retraction. T2-weighted MR images frequently showed a target-like configuration of the lesions. Contrast-enhanced MR images showed variable degrees of peripheral rim enhancement with delayed central enhancement. Forty lesions (67%) with increased FDG uptake and 20 lesions (33%) with FDG uptake similar to the surrounding liver parenchyma were found in all 6 patients. The mean maximum standardized uptake value (SUVmax) of all lesions was 3.6 ± 1.1, with a low variability of SUVmax among lesions ranging from 1.7 to 6.6. There was no relationship between lesion sizes and corresponding SUVmax. Some larger lesions demonstrated a hypermetabolic peripheral rim reflecting hypercellular tumor regions and a relatively hypometabolic central area corresponding to hypocellular stroma. Eleven lesions with increased FDG uptake on the delayed PET/CT images were found in 3 patients, and 19 lesions with decreased FDG uptake were found in all 4 patients with total 32 lesions. Conclusions MRI demonstrated morphological features of HEH and FDG PET/CT reflected the histopathological composition of the tumors. FDG uptake of HEH may be related to tumor cellularity, but not the tumor size. Dual-time-point imaging may be not useful for differentiating benign lesions from HEH. Familiarity with the morphological and functional imaging findings of HEH is useful for recognition of this rare hepatic tumor.

Apparent diffusion coefficient (ADC) measurements in pancreatic adenocarcinoma: A preliminary study of the effect of region of interest on ADC values and interobserver variability.

To assess the influence of region of interest (ROI) on tumor apparent diffusion coefficient (ADC) measurements and interobserver variability in pancreatic ductal adenocarcinoma (PDAC).

Quantification of pancreatic exocrine function of chronic pancreatitis with secretin-enhanced MRCP

AIM To obtain reference values for pancreatic flow output rate (PFR) and peak time (PT) in healthy volunteers and chronic pancreatitis (CP); to correlate quantification of secretin enhanced magnetic resonance cholangiopancreatography (SMRCP) of pancreatic fluid output following secretin with fecal elastase-1 (FE-1) tests. METHODS The present study includes 53 subjects comprised of 17 healthy individuals and 36 patients with CP from April 2011 to January 2013. The 36 patients with CP were divided into three groups of mild CP (n = 14), moderate CP (n = 19) and advanced CP (n = 3) by M-ANNHEIM classification for CP.. Fifty-three cases underwent FE-1 test and magnetic resonance imaging using 3.0 T-device (Signa EXCITE, GE Healthcare). Coronal T2-weighted single-shot turbo spin-echo, spiratory triggered, covering the papillae, duodenum and small bowel. MRCP was performed with a heavily T2-weighted fat-suppressed long TE HASTE sequence (thick slab 2D MRCP sequence), repeated every 2 min up to 11 min after 0.1 mL/kg secretin injection (Secrelux, Sanochemia(®), Germany). FE-1 test used sandwich enzyme-linked immunosorbent assay (ELISA) test (ScheBo. Tech(®), Germany). RESULTS A good linear correlation showed between the calculated volume and the actual volume by Phantom experiments. Fifty-three paired Quantification of secretin enhanced magnetic resonance cholangiopancreatography (MRCPQ) and FE-1 data sets were analyzed. The mean FE-1 of 53 cases was 525.41 ± 94.44 μg/g for 17 healthy volunteers, 464.95 ± 136.13 μg/g for mild CP, 301.55 ± 181.55 μg/g for moderate CP, 229.30 ± 146.60 μg/g for advanced CP. Also, there was statistically significant difference in FE-1 (P = 0.0001) between health and CP. The mean values of PFR and PT were 8.18 ± 1.11 mL/min, 5.76 ± 1.71 min for normal; 7.27 ± 2.04 mL/min, 7.71 ± 2.55 min for mild CP; 4.98 ± 2.57 mL/min, 9.10 ± 3.00 min for moderate CP; 4.13 ± 1.83 mL/min, 12.33 ± 1.55 min for advanced CP. Further, statistically significant difference in PFR (P = 0.0001) and PT (P = 0.0001) was observed between health and CP. Besides, there was correlation (r = 0.79) and consistency (K = 0.6) between MRCPQ and ELISA Test. It was related between M-ANNHEIM classification and PFR (r = 0.55), FE-1 (r = 0.57). CONCLUSION SMRCP can provide a safe, non-invasive and efficient method to evaluate the exocrine function of the pancreas.

Study of 320-slice dynamic volume CT perfusion in different pathologic types of kidney tumor: preliminary results.

Objective To investigate microcirculatory differences between pathologic types of kidney tumor using 320-slice dynamic volume CT perfusion. Methods Perfusion imaging with 320-slice dynamic volume CT was prospectively performed in 85 patients with pathologically proven clear cell renal cell carcinoma (RCC) (n = 66), papillary RCC (n = 7), chromophobe RCC (n = 5), angiomyolipoma (AML) with minimal fat (n = 7), or RCC (n = 78). Equivalent blood volume (Equiv BV), permeability surface-area product (PS; clearance/unit volume = permeability), and blood flow (BF) of tumor and normal renal cortex were measured and analyzed. Effective radiation dose was calculated. Results There was a significant difference in all three parameters between tumor and normal renal cortex (P<0.001). Equiv BV was significantly different between RCC and AML with minimal fat (P = 0.038) and between clear cell RCC and AML with minimal fat (P<0.001). Mean Equiv BV and BF were significantly higher in clear cell RCC than in papillary RCC (P<0.001 for both) and mean Equiv BV was higher in clear cell RCC than in chromophobe RCC (P<0.001). The effective radiation dose of the CT perfusion protocol was 18.5 mSv. Conclusion Perfusion imaging using 320-slice dynamic volume CT can be used to evaluate hemodynamic features of the whole kidney and kidney tumors, which may be useful in the differential diagnosis of these four pathologic types of kidney tumor.

Inflammatory myofibroblastic tumor: FDG PET/CT findings with pathologic correlation.

Purpose The aim of this study was to evaluate retrospectively 18F-FDG PET/CT findings of inflammatory myofibroblastic tumor (IMT) and their correlation with the pathologic findings. Patients and Methods FDG PET/CT findings were reviewed in 5 patients with IMT and 1 patient with spindle cell sarcoma transformed from IMT. PET/CT scans were performed in all 6 patients before surgery. Follow-up FDG PET/CT scan was performed in 1 patient. The location, size, maximal standardized uptake value (SUVmax), and pathologic findings of the tumors were reviewed. The correlation between the FDG uptake and pathologic findings were analyzed. Results A total of 10 lesions were detected in all 6 patients. The tumor locations were liver (n = 3), retroperitoneum (n = 2), spleen (n = 1), lung (n = 1), and bone (n = 3). Seven IMTs and 1 spindle cell sarcoma transformed from IMT were confirmed by pathology. The mean SUVmax of the pathologically proven tumors was 10.9 ± 5.5, with a high variability of SUVmax among tumors ranging from 3.3 to 20.8. The tumors (n = 7) with high cellularity had stronger FDG uptake, while the tumors (n = 1) with low cellularity had relatively low FDG uptake. The tumors with nuclear atypia and relatively high proliferative index had very strong FDG uptake, while those with low proliferative index or negative Ki-67 staining had relatively lower FDG uptake. One small tumor with abundant plasma cells showed high FDG uptake, while 1 large tumor with focal inflammatory cell infiltrate showed lower FDG uptake. One patient developed local recurrences and distant metastases revealed by the second FDG PET/CT scan 7 months after resection. Conclusions FDG uptake in IMTs varied from low to high FDG uptake, which may be due to tumor cellularity, biological behaviors of the tumor cells, the composition and the proportion of inflammatory cells, and the extent of activation of the inflammatory cells. FDG PET/CT may be useful for detection of the primary tumors, local recurrences, and distant metastases.