MRI and S‐MRCP findings in patients with suspected chronic pancreatitis: Correlation with endoscopic pancreatic function testing (ePFT)

Purpose:

To review magnetic resonance imaging (MRI) and secretin stimulated magnetic resonance cholangiopancreatography (S‐MRCP) findings of patients with suspected chronic pancreatitis and compare them with endoscopic pancreatic function testing (ePFT).

Materials and Methods:

MRI and S‐MRCP findings of 36 patients with clinically suspected chronic pancreatitis were reviewed. Baseline ductal changes, duodenal filling grades, and pancreatic duct caliber change (PDC) on S‐MRCP, mean values of pancreatic anteroposterior (AP) diameter, signal intensity ratio (SIR) between pancreas and the spleen on T1‐weighted fat saturated images, and arterial to venous (A/V) enhancement ratios were compared between groups of normal and abnormal pancreatic exocrine function determined by ePFT.

Results:

All patients (n = 24) with normal ePFT (HCO₃ >80 mEq/L) had grade 3 normal duodenal filling. Patients with abnormal ePFT (HCO₃ <80 mEq/L) (n = 12) had grade 1 (n = 1) and grade 2 (n = 11) diminished duodenal filling (P < 0.0001). PDC was 1.51 in the normal ePFT group versus 1.27 in the abnormal ePFT group (P = 0.01). No significant differences were found in terms of mean pancreatic AP diameter (21.8 vs. 19.8 cm), SIR (1.59 vs. 1.44), and A/V (1.08 vs. 1.01) between groups of normal/abnormal pancreatic exocrine function.

Conclusion:

Despite discrepancies between pancreatic exocrine function and the findings on standard MRI/MRCP, the S‐MRCP findings are comparable to ePFT in the evaluation of chronic pancreatitis. J. Magn. Reson. Imaging 2010;31:601–606. © 2010 Wiley‐Liss, Inc.     

Serial contrast-enhanced MRI of the pancreas: correlation with secretin-stimulated endoscopic pancreatic function test

RATIONALE AND OBJECTIVES: The purpose of this study was to determine the relationship between the pancreatic enhancement on serial contrast-enhanced MRI (CEMRI) and pancreatic exocrine function using the secretin-stimulated endoscopic pancreatic function test (ePFT). MATERIALS AND METHODS: A total of 30 patients with clinical symptoms consistent with chronic pancreatitis underwent CEMRI of the abdomen and ePFT within a 1- to 4-week interval. CEMRI was performed in arterial, early venous, and late venous phases. Secretin ePFT was performed with the measurement of HCO(3) concentration from the duodenal aspirates after secretin stimulation. Contrast enhancement ratio of the arterial phase to early venous phase was measured on CEMRI (SIRa/SIRv). A three-point evaluation system was used for grading the HCO(3) concentration and the enhancement ratio on MRI. For the significance of correlation, kappa statistics was used. Sensitivity and specificity of CEMRI was determined for the diagnosis of early chronic pancreatitis accepting ePFT as a reference. RESULTS: Twenty patients had identical scores on both secretin ePFT and CEMRI. Ten patients revealed discrepancy in scores. Kappa statistics revealed moderate agreement between MRI and ePFT (kappa = 0.44). Sensitivity and specificity values for the diagnosis of pancreatitis were 82% and 57%, respectively. Positive predictive value was 56%, and negative predictive value was 86%. CONCLUSION: The results of our data indicate that serial CEMRI is an appropriate imaging technique to rule out early chronic pancreatitis. However, secretin-stimulated imaging or ePFT may still be needed for the definite diagnosis of pancreatic exocrine dysfunction.     

Diffusion-weighted echo-planar MRI of lacunar infarcts

We studied 35 patients with lacunar infarcts, using diffusion-weighted echo-planar imaging (DW-EPI) at 1.5 T. The relative apparent diffusion coefficient ratio (ADCR) of each lesion was calculated and lesion conspicuity on DW-EPI was compared to that on images aquired with fast fluid-attenuated inversion recovery and T2-weighted fast spin-echo sequences. Acute small infarcts (within 3 days) were identified with DW-EPI as an area of decreased ADCR (range 0.33–0.87; mean 0.67) and high signal, subacute small infarcts (4–30 days) as a high-signal or isointense areas of decreased or nearly normal ADCR (0.54–0.98; 0.73), and chronic small infarcts (> 30 days) as low- or high-signal areas of nearly normal or increased ADCR (0.97–1.92; 1.32). In three patients, small infarcts of the brain stem in the hyperacute phase (within 6 h) were seen only with DW-EPI. In five patients, fresh small infarcts adjacent to multiple old infarcts could be distinguished only with DW-EPI. Received: 22 September 1997 Accepted: 25 November 1997     

Suspected chronic pancreatitis with normal MRCP: findings on MRI in correlation with secretin MRCP

PURPOSE: To review pancreatic MRI findings and their relationship with estimated pancreatic exocrine function on secretin-stimulated MR cholangiopancreatography (S-MRCP) in patients with clinically suspected chronic pancreatitis and normal baseline MRCP findings. MATERIALS AND METHODS: MRI findings of 26 patients with normal pancreatic duct diameter and without side branch ectasia on MRCP were evaluated. A single radiologist assessed pancreatic size, pancreatic signal intensity ratio (SIR), and arterial enhancement ratio (A/V) at head, body, and tail of the pancreas on T(1)-weighted fat-suppressed and serial contrast-enhanced images at a single session. Combined findings were graded with a composite score. Serial S-MRCP was performed at the same session with standard MRI. Correlation and differences between MRI findings and associated grade of duodenal filling (DF) or the degree of pancreatic duct caliber change (PDC) were analyzed. RESULTS: Seven patients revealed normal and 19 patients abnormal MRI findings. Significant correlation was present between the degree of DF and mean values of pancreatic size (r = 0.748), SIR (r = 0.610), A/V (r = 0.466), composite score (r = 0.833), and PDC (r = 0.554) separately. PDC correlated with SIR (r = 0.413) and composite score (r = 0.452), but not with A/V or pancreatic size. Significant differences were present between normal and abnormal DF grades in terms of mean values of associated findings of size (P = 0.001), SIR (P = 0.008), A/V (P = 0.019), and PDC (P = 0.001). CONCLUSION: Patients with clinically suspected chronic pancreatitis and normal MRCP findings may have a spectrum of MRI findings that correlate with the estimated pancreatic exocrine insufficiency on S-MRCP with the increasing number of combined findings.     

Diffusion-weighted MRI of myelination in the rat brain following treatment with gonadal hormones

Previous studies have demonstrated the ability of high-resolution diffusion-weighted MRI to show maturation of white-matter structures in the developing rat brain. The purpose of this study was to investigate the influence of gonadal steroid hormones on the rate of this development. Starting from their second postnatal day, 16 rat-pups of either sex were repeatedly treated with subcutaneous implants containing 17-beta estradiol or delta-androstene 3,17 dione, respectively. Serial T1-, T2- and diffusion-weighted MRI was performed weekly for 8 weeks using a 4.7 T unit. Maturation of anterior optic pathways and hemisphere commissures was assessed. Diffusion-weighted images were processed to produce “anisotropy index maps”, previously shown to be sensitive to white-matter maturation. Compared with untreated rat-pups, estrogen-treated animals showed accelerated, and testosterone-treated animals delayed maturation on anisotropy index maps and histological sections. In all animals, maturational changes appeared earlie on anisotropy index maps than on other MRI sequences or on myelin-sensitive stained sections. Diffusion-weighted imaging, and the construction of spatial maps sensitive to diffusion anisotropy, seem to be the most sensitive approach for the detection of maturational white-matter changes, and thus may hold potential for early diagnosis of temporary delay or permanent disturbances of white-matter development. Received: 1 September, 1995 Accepted: 27 February, 1996     

弥散MRI诊断颅内表皮样囊肿的价值

目的:探讨磁共振弥散加权成像(DWI)及表观弥散系数(ADC)图诊断颅内表皮样囊肿的价值.材料和方法:分析19例表皮样囊肿常规MRI和DWI的信号特征,定量测定表皮样囊肿、正常脑实质和脑脊液的ADC值.结果:17例表皮样囊肿T1WI、T2WI呈等或稍高于脑脊液信号,2例T1WI呈高低混杂信号.肿瘤边缘弧线形增强或不增强.19例肿瘤DWI呈明显高于脑实质和脑脊液信号,肿瘤较脑脊液的平均ADC值显著减低,较脑实质的平均ADC值显著增高.结论:DWI优于常规MRI发现颅内表皮样囊肿,DWI上表皮样囊肿的高信号可能是肿瘤组织的T2余辉效应所致.     

核磁弥散成像及增强扫描在诊断非缺血性颅脑病变中的意义

目的探讨核磁弥散成像及增强扫描在诊断非缺血性颅脑病变中的意义。方法收集经临床证实的非缺血性颅脑病变56例,均作常规MRI T2WI、T1WI、增强扫描及DWI,分析其DWI信号及增强表现。结果32例颅脑肿瘤、11例感染性病变、9例血肿、4例多发性硬化病例,病变在DWI上呈高或稍高信号。结论常规MRI T2WI、T1WI扫描图像,弥散成像及增强扫描在非缺血性颅脑病变的定性诊断中具有重要意义。     

Usefulness of diffusion/perfusion-weighted MRI in rat gliomas: correlation with histopathology

RATIONALE AND OBJECTIVES: Diffusion/perfusion-weighted MRI (DWI/PWI) can provide additional useful information in the diagnosis of patients with brain gliomas in a noninvasive fashion. However, the exact role of these new techniques is still undergoing evaluation. Our hypothesis was that DWI and PWI could be useful for assessment of growth and vascularity of implanted C6 rat gliomas. MATERIALS AND METHODS: Thirty-six rats were implanted with C6 glioma cells intracerebrally. Between 1 and 4 weeks after implantation, 8-10 rats were imaged on a clinical, 1.5-T whole-body magnetic resonance system with T(1)-weighted imaging (T(1)WI), T(2)-weighted imaging, DWI, PWI, and postcontrast T(1)WI at each weekly time point. All tumors were examined histologically; tumor cellularity and microvascular density were counted. RESULTS: On DWIs, statistical differences of apparent diffusion coefficient values for both the tumoral core and peritumoral region were present comparing tumors of 3-4 weeks' growth with tumors of 1-2 weeks' growth. Apparent diffusion coefficient value of tumoral core was negatively correlated with tumor cellularity (r = -0.682, P < .01). Statistical difference of maximal regional cerebral blood volume of tumoral core was present comparing 2-4 weeks with both 1 week after implantation and contralateral white matter (P < .01). Native vessel dilation in regions of normal brain at the periphery of the tumors at 1 week after implantation was observed. Correlation between maximal regional cerebral blood volume of tumor core and microvascular density was present (r = 0.716, P < .01). CONCLUSION: DWI and PWI has potential to characterize C6 gliomas in rats, which is a promising model similar to human gliomas.     

MRI of the pancreas: Problem solving tool

Advances in MR hardware and pulse sequence design over the years have improved the quality and robustness of MR imaging of the pancreas. Today, MRI is an indispensible tool for studying the pancreas and can provide useful information not attainable with other noninvasive or minimally invasive imaging techniques. In the present review, specific cases are reviewed where the strengths of MRI demonstrate the utility of this imaging modality as a problem solving tool. J. Magn. Reson. Imaging 2012;36:1037–1051. © 2012 Wiley Periodicals, Inc.     

Evaluation of Thin-slice Coronal Single-shot Turbo Spin-echo Diffusion-weighted Imaging of the Hand: A Comparison with Conventional Echo-planar Diffusion-weighted Imaging

We prospectively evaluated thin-slice coronal turbo spin-echo (TSE) diffusion-weighted imaging (DWI) covering a larger area with the recently-developed techniques on a 3T MRI scanner, compared with echo-planar imaging (EPI)-DWI in patients undergoing routine hand MRI. Visual score assessment and apparent diffusion coefficient (ADC) measurement were performed for patients with suspected hand tumors. TSE-DWI was superior to EPI-DWI, with less image distortion. The visual score and ADC comparison assessments proved that the image noise of TSE-DWI was acceptable.     

应用磁共振扩散加权成像评价梗阻性黄疸的初步研究

目的探讨磁共振扩散加权成像(d iffusion-we ighted im aging,DW I)评价梗阻性黄疸的可行性。方法25例梗阻性胆管扩张的患者,根据血清总胆红素水平升高与否分为有黄疸组(14例)和无黄疸组(11例),对照组为11例健康志愿者,行DW I检查,测量3组肝脏的表观扩散系数(apparent d iffusion coeffic ient,ADC)值并比较其差异。结果b值差为500 s/mm2时,各组间肝脏ADC值有统计学差异(F=25.29,P<0.01),经两两比较,有黄疸组的肝脏ADC值[(1.37±0.11)×10-3mm2/s]显著低于(P<0.01)无黄疸组[(1.63±0.14)×10-3mm2/s]和对照组[(1.67±0.08)×10-3mm2/s],无黄疸组与对照组间肝脏ADC值无显著性差异(P>0.05)。b值差为300 s/mm2时,各组间肝脏ADC值有统计学差异(F=12.22,P<0.01),经两两比较,每2组间肝脏ADC值差异均有显著性,有黄疸组[(1.58±0.21)×10-3mm2/s]低于(P<0.05)无黄疸组[(1.78±0.19)×10-3mm2/s]和对照组[(1.94±0.13)×10-3mm2/s],无黄疸组低于对照组(P=0.047)。结论肝脏ADC值测量有可能用于评价肝脏的功能。     

Quantitative secretin MRCP (MRCPQ): results in 215 patients with known or suspected pancreatic pathology

Secretin magnetic resonance cholangiopancreatography quantification (MRCPQ) of pancreatic exocrine function correlates well with steatorrhoea and conventional, non-invasive function tests. We report MRCPQ results in a variety of pancreatic conditions. A total of 215 patients [107 male, mean age 46 years (14-78)] were studied. A multi-slice MRCP sequence was performed before and at 2-min intervals after 0.1 ml/kg IV secretin. Change in small intestinal water volume was plotted against time and the flow rate derived from the gradient. Patients were classified using clinical history, MRCP, MR imaging, computed tomography (CT) [150/215 (70%)] and endoscopic retrograde cholangiopancreatography (ERCP) [56/215 (26%)] findings but not MRCPQ results. Mean, standard deviation and 95% confidence intervals were calculated. The one way ANOVA and Student's t-test were used for statistical analysis. Seventy-six patients had chronic pancreatitis, 26 were post-surgical, 34 post-acute pancreatitis, six atrophic pancreatopathy, eight with obstruction, 15 divisum, ten sphincter of Oddi dysfunction, 26 normal and 14 miscellaneous. Significant differences were observed between normals (mean+/-SD; 7.4 +/- 2.9 ml/min) and severe chronic pancreatitis (5.3 +/- 2.4) (P = 0.018), pancreatic atrophy (3.8 +/- 3.1) (P = 0.013) or duct obstruction (5.3 +/- 2.4) (P = 0.047)) and between moderate (7.0 +/- 3.0) (P = 0.03) and severe chronic pancreatitis. MRCPQ can be used to quantify function across the spectrum of pancreatic disease and showed significant differences between several different pathologies.     

Ileal Crohn's disease: MRI with endoscopic correlation

Purpose

To evaluate activity staging of Crohn's disease (CD) measured with MR-enterography using ileoscopy as reference standard.

Materials and methods

A prospective study was made of 61 patients with CD. All patients underwent MR-enterography and ileoscopy. MRI activity was measured by means of an ad hoc developed score, as well as by analysis of the imaging findings, and was compared with the SES-CD score obtained via ileoscopy. Examinations were performed using a 1.0 T scanner.

Results

MRI score discriminates between active and inactive disease with an area under the ROC curve of 0.941. Overall correlation with the standard reference SES-CD score was moderate to strong (Spearman's r = 0.62 p < 0.001).Agreement between both methods in staging patients with ileal CD as inactive, mild or moderate to severe was good (Cohen's κ = 0.60). Differences in means of the MRI activity scores of the three groups showed statistical significance (p < 0.01).

Conclusions

The MRI score is a reliable predictor of activity in ileal CD and can stage patients in a way comparable to endoscopy. 1.0 T scans are valid for performing radiological evaluation of ileal Crohn's disease.     

子宫内膜癌的DWI成像特征及其与PCNA、Ki-67表达相关性研究

目的:本研究拟利用PCNA及Ki-67的特殊标记物功能,通过测定不同恶性程度子宫内膜癌组织中的PCNA和Ki-67不同表达程度,及其与DWI图像ADC值及rADC值的相关性研究,探讨应用DWI对于子宫内膜癌恶性程度分子水平定量研究的鉴别诊断价值。方法:对23例子宫内膜癌患者在术前行常规MRI检查并进行ADC值的测定(b值为800s/mm2)。闭孔内肌作参比部位,测量内膜癌的rADC值。所有病例均经病理证实,包括高分化8例,中分化10例,低分化5例。用免疫组织化学染色方法(SP法)检测23例子宫内膜癌标本中PCNA及Ki-67的表达情况。结果:子宫内膜癌随着肿瘤恶性分化程度降低,各组的ADC及rADC值存在下降趋势。低分化组ADC、rADC值〔(0.79±0.14)×10-3mm2/s、0.55±0.11〕显著低于高分化组〔(1.05±0.18)×10-3 mm2/s、0.80±0.22〕,中分化组〔(0.89±0.15)×10-3 mm2/s、0.66±0.16〕ADC、rADC值与低分化组及高分化组相比均无统计学差异。子宫内膜癌PCNA、Ki-67表达程度与肿瘤ADC、rADC值呈显著性负相关。结论:子宫内膜癌DWI成像ADC、rADC值的测量有助于评价并鉴别肿瘤不同病理级别并有潜力作为评价肿瘤增殖程度的无创性方法。子宫内膜癌PCNA、Ki-67表达程度与ADC、rADC值显著性负相关,提示核磁共振扩散加权成像有潜力从分子水平反映细胞增殖程度。     

Diffusion-weighted interleaved echo-planar imaging with a pair of orthogonal navigator echoes

This work describes a diffusion-weighted (DW) interleaved echo-planar imaging (IEPI) method for use on either conventional whole-body scanners or scanners equipped with highspeed gradient and receiver hardware. In combination with cardiac gating and motion correction with a pair of orthogonal navigator echoes, the presented method is time-efficient, compensates for patient motions, and is less sensitive to image distortions than single-shot methods. The motion-correction scheme consists of correction for constant and linear phase terms found from the orthogonal navigator echoes. The correction for the linear phase term in the phase-encode direction includes gridding the data to the Cartesian grid. The DW IEPI was used to image a phantom rotating about the slice-select direction, and motion correction was performed to eliminate ghost artifacts arising from motion in either the readout- or phase-encoding directions. DW IEPI with motion correction was performed on a normal volunteer and on a patient with a 26-day-old region of ischemia over much of the right hemisphere.     

Diffusion-weighted MRI and selection of patients for fibrinolytic therapy of acute cerebral ischaemia

Treatment of patients with acute cerebral ischaemic events remains controversial. We investigated the reversibility of high signal intensity on diffusion-weighted (DW) MRI after acute local intra-arterial fibrinolysis (LIF) and the feasibility of DW MRI for selecting patients for acute LIF. Nine patients with acute middle cerebral artery embolic occlusion underwent single-photon emission computed tomography (SPECT) and DW MRI followed by acute LIF using tissue plasminogen activator. Recanalisation was observed in all patients, and eight improved clinically. The area of high signal intensity on pretreatment DW MRI was smaller than the low-uptake area on SPECT in all patients, and went on to infarction, as detected by MRI or CT 3 days after onset in all patients. It appears to correlate, at least clinically, with irreversible brain damage. Therefore, acute LIF should not be performed in patients with areas of high signal intensity in the cortex responsible for the symptoms. SPECT remains important, because areas normal on DW MRI with low uptake on SPECT often contribute to functional prognosis. Received: 23 March 1999/Accepted: 30 August 1999     

小型猪慢性胰腺炎胰管改变的MRI研究

目的 探讨小型猪胰管结扎法致慢性胰腺炎(CP)胰管的MRI表现及其与CP严重度的相关性.方法 健康小型猪30头,数字表法随机抽取5头作正常对照组,余下25头为实验组.采用胰管结扎法造模2～18周后行MRI检查观察胰腺及胰管.处死取胰腺行病理组织学分析并分3度.胰管直径、胰管分支显示率与CP严重度的关系采用Spearman相关系数分析.结果 实验组21头(84.0%)形成CP,轻度7头、中度8头、重度6头.轻度CP胰管均显影且3头胰管边缘细锯齿状.中、重度CP胰右管、胰左管、胰中管扩张成"人"字形.轻、中、重度CP胰管直径分别为(0.9±0.3)mm、(2.9±1.4)mm、(4.8±1.2)mm,随CP严重度增加而增加(r=0.837,P＜0.05).胰管分支显示率(轻度为0、中度为3/8、重度为5/6),随CP严重度增加而上升(r=0.990,P＜0.05).结论 胰管结扎法致小型猪阻塞性CP扩张胰管整体呈"人"字形,此种CP在MRI上胰管改变反映了 CP的严重程度.     

Diffusion-weighted MRI suggests the coexistence of cytotoxic and vasogenic oedema in a case of deep cerebral venous thrombosis

We report a 20-year-old woman who suffered headaches before presenting with a state of fluctuating vigilance. MRI showed diffuse high signal in the basal ganglia bilaterally on diffusion- and T2-weighted images, which had areas of both low and high apparent diffusion coefficient, presumed to correspond to cytotoxic and vasogenic oedema. MR venography showed no flow in the deep cerebral veins or straight sinus. Heparin was given, with clinical recovery. On follow-up MRI, the appearances became normal. Received: 17 December 1999/Accepted: 15 February 2000