Diffusion-weighted Resonance Imaging Research Articles

Native T1 mapping for differentiating the histopathologic type, grade, and stage of rectal adenocarcinoma: a pilot study

BackgroundPrevious studies have indicated that T1 relaxation time could be utilized for the analysis of tissue characteristics. T1 mapping technology has been gradually used on research of body tumor. In this study, the application of native T1 relaxation time for differentiating the histopathologic type, grade, and stage of rectal adenocarcinoma was investigated.MethodsOne hundred and twenty patients with pathologically confirmed rectal adenocarcinoma were retrospectively evaluated. All patients underwent high-resolution anatomical magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), and T1 mapping sequences. Parameters of T1 relaxation time and apparent diffusion coefficient (ADC) were measured between the different groups. The diagnostic power was evaluated though the receiver operating characteristic (ROC) curve.ResultsThe T1 and ADC values varied significantly between rectal mucinous adenocarcinoma (MC) and non-mucinous rectal adenocarcinoma (AC) ([1986.1 ± 163.3 ms] vs. [1562.3 ± 244.2 ms] and [1.38 ± 0.23 × 10−3mm2/s] vs. [1.03 ± 0.15 × 10−3mm2/s], respectively; P < 0.001). In the AC group, T1 relaxation time were significantly different between the low- and high-grade adenocarcinoma cases ([1508.7 ± 188.6 ms] vs. [1806.5 ± 317.5 ms], P < 0.001), while no differences were apparent in the ADC values ([1.03 ± 0.14 × 10−3mm2/s] vs. [1.04 ± 0.18 × 10−3mm2/s], P > 0.05). No significant differences in T1 and ADC values were identified between the different T and N stage groups for both MC and AC (all P > 0.05).ConclusionsNative T1 relaxation time can be used to discriminate MC from AC. The T1 relaxation time was helpful for differentiating the low- and high-grade of AC.

Preoperative prediction of extramural venous invasion in rectal cancer by dynamic contrast-enhanced and diffusion weighted MRI: a preliminary study

BackgroundTo explore the value of the quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) parameters in assessing preoperative extramural venous invasion (EMVI) in rectal cancer.MethodsEighty-two rectal adenocarcinoma patients who had underwent MRI preoperatively were enrolled in this study. The differences in quantitative DCE-MRI and DWI parameters including Krans, Kep and ADC values were analyzed between MR-detected EMVI (mrEMVI)-positive and -negative groups. Multivariate logistic regression analysis was performed to build the combined prediction model for pathologic EMVI (pEMVI) with statistically significant quantitative parameters. The performance of the model for predicting pEMVI was evaluated using receiver operating characteristic (ROC) curve.ResultsOf the 82 patients, 24 were mrEMVI-positive and 58 were -negative. In the mrEMVI positive group, the Ktrans and Kep values were significantly higher than those in the mrEMVI negative group (P < 0.01), but the ADC values were significantly lower (P < 0.01). A negative correlation was observed between the Ktrans vs ADC values and Kep vs ADC values in patients with rectal cancer. Among the four quantitative parameters, Ktrans and ADC value were independently associated with mrEMVI by multivariate logistic regression analysis. ROC analysis showed that combined prediction model based on quantitative DCE parameters and ADC values had a good prediction efficiency for pEMVI in rectal cancer.ConclusionThe quantitative DCE-MRI parameters, Krans, Kep and ADC values play important role in predicting EMVI of rectal cancer, with Ktrans and ADC value being independent predictors of EMVI in rectal cancer.

Stroke in Takayasu arteritis with concomitant tuberculosis: an unusual pediatric case report

BackgroundStroke is a lethal complication of polyarteritis in children. Takayasu arteritis is a rare disease with an unknown etiology and is known to mainly affect young women. In this report, we present the case of a Chinese boy diagnosed with TA results in stroke, originally presenting in the context of latent tuberculosis infection and then developing active tuberculosis.Case presentationThe patient was a 14-year-old child who developed a latent tuberculosis infection at age 5 after coming in close contact with his grandfather, who had tuberculosis. However, he did not receive any anti-tuberculosis medications at that time. At age 9, he was hospitalized for symptoms of "dizziness and headache" and was diagnosed with Takayasu arteritis and hypertension; however, tuberculosis was not diagnosed. Only antihypertensive drugs were administered without considering the possible pathogenic factors of tuberculosis infection. At age 14, he was rehospitalized for "fever and cough" and was diagnosed with active pulmonary tuberculosis as an analysis of his fiberoptic bronchoscopy sample using the Gene-Xpert assay was positive for Mycobacterium tuberculosis. However, after 2 months of taking oral anti-tuberculosis drugs, his blood pressure continued to rise, and he presented with numbness and weakness of the right limb and a deviation of the right side of his mouth. Computed tomography angiography of his head and neck revealed that the walls of the left subclavian artery and bilateral vertebral arteries were thickened, and the lumen was significantly narrowed. In a recent examination, magnetic resonance imaging and diffusion-weighted imaging of the head showed infarctions in the right basal ganglia area close to the left lateral ventricle. Our patient was treated with methotrexate, tocilizumab and glucocorticoids to control he continued active vasculitis.ConclusionsThe possible association of tuberculosis and Takayasu arteritis complicated by stroke needs to be considered, especially in children who had prior contact with a family member with tuberculosis infection. The temporal relationship between TA and infection with Mycobacterium tuberculosis in our patient suggests a compelling link that demands further investigation.

Novel method using DW-MRI and ADC images to guide stereotactic biopsy for the diagnosis small primary angiitis of the central nervous system: a case report

ObjectiveTo determine the role of diffusion-weighted magnetic resonance imaging (DW-MRI) and apparent diffusion coefficient (ADC) imaging to guide stereotactic biopsy for the diagnosis of intracranial angiitis.Case presentationIn a 28-year-old woman who had experienced inactive headache and right limbs numbness for 4 days, preoperative magnetic resonance (MR) scanning, enhanced scanning, diffusion tensor imaging, magnetic resonance spectroscopy, diffusion-weighted imaging (DWI), and ADC image scanning were performed. Stereotactic biopsy was performed in one target where the area of edema detected with MR FLAIR, and two targets where the area shown as a high-value and a lower value area in the DWI/ADC image. Pathological examinations together with computed tomographic and enhanced MRI scans were conducted after surgery. A preoperative enhanced MRI scan showed a uniform low-intensity lesion in the patient’s left centrum semiovale, with a volume of 3.1 cm3. The DWI and ADC images showed uneven high-intensity signals and different ADC values in the lesion area, respectively. During surgery, tissues around the lesion and the lesion center were sampled at the three selected targets. The postoperative pathological diagnosis was primary angiitis of the central nervous system, and the patient was given anti-inflammatory medication and hormone therapy. The 3-year follow-up confirmed that the patient had recovered well, with a Glasgow Outcome Scale score of five.ConclusionDW-MRI and ADC images can be reliably used to determine the location of small intracranial lesions, and guide stereotactic biopsy to facilitate the diagnosis of primary vasculitis of the central nervous system.

Dynamic contrast enhanced-MRI and diffusion-weighted image as predictors of lymphovascular invasion in node-negative invasive breast cancer

BackgroundLymphovascular invasion (LVI) is an important risk factor for prognosis of breast cancer and an unfavorable prognostic factor in node-negative invasive breast cancer patients. The purpose of this study was to evaluate the association between LVI and pre-operative features of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) in node-negative invasive breast cancer.MethodsData were collected retrospectively from 132 cases who had undergone pre-operative MRI and had invasive breast carcinoma confirmed on the last surgical pathology report. MRI and DWI data were analyzed for the size of tumor, mass shape, margin, internal enhancement pattern, kinetic enhancement curve, high intratumoral T2-weighted signal intensity, peritumoral edema, DWI rim sign, and apparent diffusion coefficient (ADC) values. We calculated the relationship between presence of LVI and various prognostic factors and MRI features.ResultsPathologic tumor size, mass margin, internal enhancement pattern, kinetic enhancement curve, DWI rim sign, and the difference between maximum and minimum ADC were significantly correlated with LVI (p < 0.05).ConclusionsWe suggest that DCE-MRI with DWI would assist in predicting LVI status in node-negative invasive breast cancer patients.

Analysis of correlation between magnetic resonance imaging features and prognosis of invasive pituitary adenoma

Objective: To explore the application of conventional nuclear magnetic resonance imaging, diffusion-weighted imaging and dynamic contrast-enhanced imaging in invasive pituitary adenoma, and to study the correlation between its imaging features and prognosis. Methods: The imaging manifestations (including T1WI, T2WI, ADC and dynamic contrast-enhanced MR), clinical features and pathological data of 47 cases of invasive pituitary adenomas (IPA) in Tianjin Huanhu Hospital from June 2017 to June 2018 were retrospectively analyzed, and compared with 16 cases of non-invasive pituitary adenoma (NIPA). The differences in tumor/white matter signal intensity ratio on T1WI and T2WI images, MR signs, ADC values and time signal-curve type, peak enhancement time and average enhancement rate between the two groups were observed. Postoperative MR enhanced scan and related hormone results were reviewed to evaluate the prognosis of all patients. Logistic stepwise regression analysis was used to analyze the relationship between IPA imaging characteristics and prognosis. Results: The location, shape, size, Knosp classification and ADC value of tumors were significantly different between IPA and NIPA groups (χ(2) values were 41.344, 21.818, 28.596 respectively, t values were 5.869, 11.720 respectively, all P<0.05). The majority of T1WI, T2WI and enhanced heterogeneous signals occurred in IPA group (P<0.05). IPA showed two-stage enhancement characteristics of rapid enhancement and fast subsidence phase. There were significant differences in peak enhancement time between intrasellar tumors and invasive cavernous sinus tumors. There were no significant differences in signal intensity of T1 and diffusion limitation and two-stage enhancement characteristics between the two groups (all P>0.05). There was a significant correlation between the ratio of tumor body/white matter signal on T2WI, ADC value and the constitution of invasive pituitary tumors (all P<0.05). In IPA, 9 cases(19%) were totally resected, 25 cases(53%) subtotally resected and 13 cases(28%) partially resected. Postoperative symptoms were improved in 29 cases(62%), alleviated in 6 cases(13%), unhealed in 3 cases(6%), assisted drug therapy in 7 cases and radiotherapy in 15 cases. All cases were followed up for 7 to 16 months, with a median time of 12.5 months. Eight cases recurred, with a recurrence rate of 17%. There were significant differences in the total/subtotal resection rate, the improvement rate of symptoms and the need for adjuvant treatment among IPA with different texture (all P<0.05).Knosp grade, tumor size and the ratio of tumor body to white matter on T2WI were associated with IPA recurrence (all P<0.05). Conclusion: It is helpful to diagnose IPA by analyzing the distribution, shape, size, ADC value and signal difference of tumors in sella turcica region through MR and DWI signs. Combined with dynamic contrast enhancement features, the invasion of IPA and its surrounding tissues can be early judged, and the texture of the tumors can be assessed by imaging signs, so as to better evaluate the therapeutic effect and prognosis of IPA.

Aches and Pains in a Patient With History of Prostatectomy: Extensive Skeletal Metastasis Picked up by Diffusion-Weighted Magnetic Resonance Imaging

A 64-year-old gentleman presented to the out-patient with complaints of generalized body ache. He had a history of prostate cancer for which robotic radical prostatectomy (RP) was done earlier. The levels of prostate specific antigen (PSA) and alkaline phosphatase (ALP) were significantly elevated. Skeletal radiograph showed only few sclerotic foci. Magnetic resonance imaging whole-body diffusion-weighted image (MRI-WB-DWI) however revealed the presence of diffuse skeletal metastasis. In any elderly male who presents with generalized body pain, eliciting a good history should not be overlooked. With a history of prostate cancer, diffuse metastases should be high in the list of differential diagnosis. Though there are several imaging methods to detect metastases, MRI-WB-DWI is a welcome alternative to the established methods. Patients who undergo RP for prostate cancer should be counselled regarding the importance of follow-up of their PSA levels. J Med Cases. 2020;11(9):275-278 doi: https://doi.org/10.14740/jmc3545

Cavitation of symptomatic acute single small subcortical infarctions.

To investigate cavitation of symptomatic acute single small subcortical infarctions (SSSI). Acute SSSI were diagnosed with magnetic resonance (MR) diffusion-weighted imaging (DWI) combined with apparent diffusion coefficient (ADC) sequence on follow-up MR imaging. Cavitation of the acute SSSI was comprehensively viewed on FLAIR, T2-, and T1-weighted sequences. We enrolled 123 patients with acute SSSI. The follow-up median interval was 303 (125-390) days. The lesions of SSSI evolved into cavitation in 93 patients (75.6%), evolved into WMHs in nine patients (7.3%), and were no visible in 21 patients (17.1%). Cavitation was independently associated with larger infarct diameter on baseline DWI [odds ratio (OR), 1.250, 95% CI (1.078-1.451), P= 0.003], higher score of baseline old lacunar infarct [OR 3.44, 95% CI (1.49-7.91), P= 0.004], and lower rate of dyslipidemia [OR 0.30, 95% CI (0.10-0.76), P= 0.013]. Cavitation occurred more in the setting of small vessel diseased brain and less in the SSSI of possible atherosclerotic etiology. This suggested that the etiology of infarct was associated with cavitation after acute SSSI.

Magnetic resonance diffusion weighted imaging using constrained spherical deconvolution-based tractography of the extracranial course of the facial nerve.

To evaluate the accuracy of magnetic resonance diffusion weighted imaging (DWI) featuring constrained spherical deconvolution-based tractography in tracking the extracranial course of the facial nerve to provide a reliable facial nerve map to facilitate well-tolerated and effective tumor resection. Magnetic resonance DWI was conducted on 2 parotid-healthy cadaveric patients with various protocols to identify the best representation of the extracranial facial nerve tract. This was subsequently correlated to dissection of the facial nerves to ascertain anatomic validation. These protocols were applied to 2 live, parotid-healthy patients to assess feasibility of in vivo facial nerve tract identification. Correlations between imaged tracts and the anatomic course of the extracranial facial nerve were identified to an accuracy of 1 mm. The main trunk and bifurcation tracts were identified on imaging. Fractional anisometry values in cadaveric and live patients were within the range expected for the facial nerve within the parotid gland. Our results indicated the potential for accurate 3-dimensional visualization of the extracranial course of the facial nerve, which could have diagnostic implications in differentiating benign from malignant tumors and, crucially, neural involvement. Preoperative planning applications of DWI could help in planning surgical approaches and providing focused counseling.

Role of diffusion-weighted magnetic resonance imaging in evaluation of bone marrow edema of the knee

Background Bone marrow edema (BME) has not been recognized as a significant pain generator or as a primary contributor to disease until recently. BME is characterized by a nonspecific pattern of ill-defined high signal intensity on short-tau inversion recovery and T2-weighted MRI and low signal intensity on T1-weighted images. Objective To assess the value of diffusion-weighted MRI in the diagnosis and evaluation of BME at the knee region. Patients and methods This study was conducted on 130 patients referred with clinical suspicion of knee edema with or without history of trauma. They were divided into group ‘A,’ with lesions less than 15 mm, and group ‘B,’ with lesions greater than 15 mm. Their ages ranged between 9 and 75 years, with a mean age of 42 years. There were 43 females and 87 males. Results Between groups A and B, we found that bone marrow lesions (BMLs) were approximately two times larger on apparent diffusion coefficient (ADC) maps than on fat-saturated (FS) proton density (PD)-weighted turbo spin echo images. The most important value of adding the ADC-derived maps in routine MRI examination of the knee is to show additional BMLs that only can be detected at the ADC maps but could not be detected at the FS PD. Approximately 27 more lesions in 27 patients and one patient with two more lesions were detected. These nonconcordant lesions accounted totally for 29 more BMLs. Conclusion MRI is the mainstay of diagnosis, staging, and management plan of knee traumatic and nontraumatic disorders. ADC maps are more sensitive than corresponding FS PD-weighted turbo spin echo images allowing for detection of significantly more and larger BMLs. In addition, they represent a valuable add-on in knee imaging protocols.

Diffusion-weighted imaging for identifying patients at high risk of tumor recurrence following liver transplantation

BackgroundTumor recurrence is the major risk factor affecting post-transplant survival. In this retrospective study, we evaluate the prognostic values of magnetic resonance (MR) diffusion-weighted imaging (DWI) in liver transplantation for hepatocellular carcinoma (HCC).MethodsFrom April 2014 to September 2016, 106 HCC patients receiving living donor liver transplantation (LDLT) were enrolled. Nine patients were excluded due to postoperative death within 3 months and incomplete imaging data. The association between tumor recurrence, explant pathologic findings, and DWI parameters was analyzed (tumor-to-liver diffusion weighted imaging ratio, DWIT/L; apparent diffusion coefficients, ADC). The survival probability was calculated using the Kaplan–Meier method.ResultsSixteen of 97 patients (16%) developed tumor recurrence during the follow-up period (median of 40.9 months; range 5.2–56.5). In those with no viable tumor (n = 65) on pretransplant imaging, recurrence occurred only in 5 (7.6%) patients. Low minimum ADC values (p = 0.001), unfavorable tumor histopathology (p < 0.001) and the presence of microvascular invasion (p < 0.001) were risk factors for tumor recurrence, while ADCmean (p = 0.111) and DWIT/L (p = 0.093) showed no significant difference between the groups. An ADCmin ≤ 0.88 × 10− 3 mm2/s was an independent factor associated with worse three-year recurrence-free survival (94.4% vs. 23.8%) and overall survival rates (100% vs. 38.6%).ConclusionsQuantitative measurement of ADCmin is a promising prognostic indicator for predicting tumor recurrence after liver transplantation.

Diffusion-weighted Magnetic Resonance Imaging Evaluates Salivary Gland Function Damage in Nasopharyngeal Carcinoma Patients Treated with Intensity-modulated Radiation Therapy

Diffusion-weighted Magnetic Resonance Imaging Evaluates Salivary Gland Function Damage in Nasopharyngeal Carcinoma Patients Treated with Intensity-modulated Radiation Therapy

Application of diffusion-weighted magnetic resonance imaging in the differential diagnosis of hydronephrosis and pyonephrosis

Objective To study the effect of diffusion-weighted magnetic resonance imaging (DW-MRI) in the differential diagnosis of hydronephrosis and pyonephrosis. Methods From March 2015 to October 2017, 50 patients with renal stone and highly suspected infectious hydronephrosis underwent renal DW-MRI, and clinical materials were collected and analyzed retrospectively. Seventeen male and 33 female patients were enrolled with a mean age of (49.40±10.51) years. The median maximum diameter of renal stone was 30.30 (17.38, 56.01) mm and hydronephrosis was 46.39 (34.33, 56.55) mm. No pyonephrosis was diagnosed by preoperative ultrasound or CT, while 29 cases of hydronephrosis and 21 cases of pyonephrosis were reported by preoperative DW-MRI. Final diagnoses of hydronephrosis and pyonephrosis were made according to whether the pelvic urine drainage was purulent or not during the surgery. DW-MRI reports and characteristics of DW images were analyzed retrospectively. Apparent diffusion coefficient (ADC) was calculated and ADC map constructed, which was compared between the two groups. Receiver operating characteristic curve (ROC) was drawn to analyze the area under curve (AUC) and the optimal cutoff of ADC value, with sensitivity and specificity. Results Thirty-three patients of hydronephrosis and 17 pyonephrosis were confirmed intraoperatively. The overall accuracy of diagnosis using DW-MRI was 84.00% (42/50), with sensitivity of 88.24% (15/17) and specificity of 81.82% (27/33). Among 30 patients who underwent CT scan in our hospital, mean CT value of 18 hydronephrosis was (7.03±3.26) HU and that of 12 pyonephrosis was (8.67±3.52) HU, with no statistical significance (P>0.05). On DW image, when b≥500 s/mm2, hydronephrosis signal intensity was lowered apparently, whereas pyonephrosis signal intensity was intensified. On ADC map, hydronephrosis appeared as hyperintensity, whereas pyonephrosis appeared as hypointensity. The mean ADC value of pyonephrosis group was lower than hydronephrosis group [(1.53±0. 58)×10-3 mm2/s vs. (2.86±0.56)×10-3 mm2/s, P<0.01]. ROC analysis revealed that AUC=0.92(95%CI 0.80-0.98), and the cut-off value of ADC for pyonephrosis diagnosis was 1.39×10-3 mm2/s, of which the sensitivity and specificity was 94.12% and 84.85% respectively. Conclusions Signal of pyonephrosis was enhanced on DW image, while decreased on ADC image. The ADC value of pyonephrosis was much lower than that of hydronephrosis, with which the differential diagnosis between pyonephrosis and hydronephrosis could be made efficiently. Key words: Hydronephrosis; Pyonephrosis; Urosepsis; Diffusion-weighted imaging; Apparent diffusion coefficient

Diffusion weighted magnetic resonance imaging in differentiation of small focal liver lesions ( and #8804; 10 mm) detected in patients with extrahepatic primary malignancy

The purpose of the study is to assess the advantages of diffusion weighted resonance imaging (DWI) prospectively in the metastasis and benign differentiation of small (≤ 10 mm) focal liver lesions (FLL) detected in routine ultrasonography and/or computed tomography screening of patients with extrahepatic primary malignancy. A total of 77 small FLLs (33 metastasis, 27 cyst, 17 hemangioma) of 53 patients who received DWI in addition to conventional magnetic resonance imaging were assessed by 2 independent readers prospectively. Apparent diffusion coefficient (ADC) values were measured for each FLL. T-test was used to assess the statistically significant difference between average ADC values in differentiating between metastasis and benign FLLs. In the metastasis and benign differentiation of small FLLs, optimum cutoff values of ADC values were found by using receiver operating characteristic (ROC) analysis. Average ADC values of small focal liver metastases were statistically significantly lower than those of benign FLL (p < 0.001). Small focal liver metastases were differentiated from benign FLL with 100% sensitivity and 97.1% specificity by using 1.44 x 10-3 s/mm2 cutoff ADC value. This study shows that DWI can be useful in differentiating whether incidentally found small FLL is metastasis in patients who have extrahepatic primary malignancy.

Nuclear magnetic resonance evaluation of inflammatory activity from chronic viral Hepatitis B.

Objectives:To discuss the value of applying magnetic resonance diffusion-weighted imaging (DWI) to evaluate inflammatory activity from chronic viral hepatitis B.Methods:One hundred forty-two patients with chronic viral hepatitis B who received treatment at The Fifth Medical Center of Chinese PLA General Hospital from January 2014 to December 2015 and 20 healthy persons in the control group who were scheduled to undergo nuclear magnetic resonance scanning and DWI examinations (b value = 0, 800 s/mm2), and the apparent diffusion coefficients (ADCs) were measured and compared with the biopsy results of hepatic tissue.Results:The ADC value of the group with hepatitis B was lower than that of the healthy group (P<0.05), and the ADC value of the group with mild inflammation (G1) significantly differed from that of the group with moderate inflammation (G2) and that of the group with severe inflammation (G3-G4) (P<0.05).Conclusions:Magnetic resonance diffusion-weighted imaging technology has high clinical value for evaluating the inflammatory activity from chronic hepatitis B, and the measured ADC value corresponds to the pathological grade well, so this method is worth clinical promotion and application.

Infarct morphology assessment in patients with carotid artery/middle cerebral artery occlusion using fast fluid-attenuated inversion recovery (FLAIR) vascular hyperintensity (FVH).

We aim to evaluate the value of fast fluid-attenuated inversion recovery (FLAIR) vascular hyperintensity (FVH) in assessing infarct morphology in patients with symptomatic internal carotid artery (ICA) or middle cerebral artery (MCA) occlusions. Magnetic resonance (MR) diffusion-weighted imaging (DWI) FLAIR sequences, and carotid/cerebral magnetic resonance angiography of 102 patients with symptomatic ICA or MCA occlusions were evaluated. The location and score of FVH were determined using Olindo’s method; patients were classified as having Low or High FVHs based on FVH score, and either Distal or Proximal FVH based on FVH location. The differences between infarct morphologies were analyzed. FVH were detectable in 62 patients with High FVH and in 40 patients with Low FVHs based on the Olindo’s scale. There were no statistically significant differences in age, gender, hypertension, diabetes, hyperlipidemia, smoking history, and vascular occlusive site between High and Low FVHs patients, except for infarct morphology (P<0.01). Patients with Distal FVH presented with significant (P<0.01) perforating artery and border zone infarcts, whereas those with Proximal FVH had significant (P<0.01) large territorial infarcts. The scores and locations of FVH could be a predictive imaging marker for infarct morphology in patients with symptomatic ICA or MCA occlusion.

The role of magnetic resonance cholangiopancreatography and diffusion-weighted imaging for the differential diagnosis of obstructive biliary disorders

Background: Although endoscopic retrograde cholangiopancreatography (ERCP) is accepted as the gold standard, there is a place for magnetic resonance cholangiopancreatography (MRCP) and diffusion-weighted imaging (DWI) in the diagnosis of obstructive biliary disorders.Aim: To compare the findings of MRCP with ERCP in patients with obstructive biliary disorders and to investigate the diagnostic efficacy of MRCP combined with DWI.Study design: Retrospective, analytic, cross-sectional study.Methods: The MRCP images of 126 patients who underwent both MRCP and ERCP owing to biliary obstruction were reviewed. Nine patients were excluded because of incomplete diagnostic workup or a long period (&gt;3 months) between MRCP and ERCP. Ninety-two patients underwent DWI, which was also evaluated. The sensitivity, specificity and accuracy of MRCP and DWI were analysed.Results: The sensitivity, specificity and accuracy of MRCP according to ERCP results as the gold standard was 97%, 71% and 93% for assessment of biliary dilatation; 100%, 94.7% and 97.5% for the diagnosis of choledocholithiasis; 93.7%, 100% and 99% for the identification of benign strictures; 100%, 100% and 100% for the diagnosis of malignant tumours; and 100%, 100% and 100% for the detection of complicated hydatid cysts; respectively. The sensitivity and specificity of DWI for the diagnosis of malignant tumour was 100%. In the detection of choledocholithiasis, the sensitivity and specificity of DWI was 70.8% and 100%.Conclusions: MRCP is an alternative, non-invasive, diagnostic modality, comparable with ERCP for the evaluation of pancreaticobiliary diseases. DWI can be helpful for diagnosis of choledocholithiasis and tumours.

Value of Texture Feature Analysis in the Differential Diagnosis of Hepatic Cyst and Hemangioma in Magnetic Resonance Imaging.

Objective To investigate the difference of texture on conventional T2-weighted image (T2WI) between hepatic cyst and hepatic hemangioma. Methods All the subjects included 156 patients with hepatic cyst [A group:100 cases with equi or low signal on diffusion weighted imaging (DWI);B group:56 cases with high signal on DWI] and 100 patients with hemangioma (C group). Conventional magnetic resonance imaging T2WI,DWI and dynamic contrast enhancement were performed on all the patients,and the texture analysis was applied with the images of T2WI,and the texture parameters included angular second moment,contrast,correlation,inverse difference moment,and entropy. Independent sample t-test and Aspin-Welch test were performed for the comparisons among groups. Results All the texture parameters showed significant difference among groups [(A+B) group vs. C group:ρ angular second moment=0.000,ρcontrast=0.000,ρcorrelation=0.000,Pinverse difference moment=0.822,ρentropy=0.000;A group vs. C group:ρangular second moment=0.000,ρcontrast=0.000,ρcorrelation=0.000,ρinverse difference moment=0.092,ρentropy=0.000;B group vs. C group:ρangular second moment=0.000,ρcontrast=0.000,ρcorrelation=0.000,ρinverse difference moment=0.046,ρentropy=0.009],and receiver operating characteristic curve analysis demonstrated that contrast and correlation had high differential diagnostic values between hepatic cyst and hemangioma. Conclusion Hepatic cyst and hemangioma present evident different texture characteristics,and the texture analysis may be considered as a simple and effective tool in the differential diagnosis between hepatic cyst and hemangioma based on the images of T2WI.

The application of magnetic resonance T2-mapping and DWI imaging in diagnosis of early cartilage degeneration of the knee joint

Objective To study the application of magnetic resonance T2-mapping and diffusion weighted imaging(DWI) in diagnosis of early cartilage degeneration of the knee joint. Methods 56 patients with clinical intends to diagnosis of early osteoarthritis of the knee were set as observation group, another 56 healthy volunteers were selected as healthy control group.The subjects of the two groups were given knee MRI T2 mapping and DWI, the T2 acquisition value and ADC value of the two groups were analyzed and compared. Results In the observation group, the side of the femoral (37.18±4.09), lateral tibial (32.16±2.75) and hip (34.56±4.21) were significantly lower than those in the healthy control group[femoral side (49.87±5.02), tibial side (47.34±5.01), hip surface (51.23±5.19)](t=20.16, 18.36, 23.65, all P<0.05). Conclusion Magnetic resonance T2-mapping and DWI imaging can be found in the early knee cartilage degeneration, can lead to the rise of T2 and ADC value, so there is no cartilage damage to the cartilage damage. Key words: Magnetic resonance imaging; Cartilage; Osteoarthritis, knee

Diagnostic performance of [18F] fluorodeoxyglucose PET/CT and diffusion-weighted magnetic resonance imaging for the evaluation of treatment response to induction chemotherapy followed by definitive chemoradiotherapy in locally advanced head and neck squamous cell carcinoma

Recently, functional imaging such as fluorine-18 fludeoxyglucose integrated with computed tomography (18F-FDG-PET/CT) or difusion-weighted magnetic resonance imaging (DW-MRI) represent an area of highly active research in oncology. DW-MRI is an advanced imaging modality that records the molecular diffusion of protons to further assess tissue caracter, providing the opportunity to differentiate post-treatment tumour recurrence from chemoradiotherapy-induced local tissue changes (1). In the case of PET/CT, besides providing useful diagnostic information regarding pretreatment staging (2,3) and post-treatment follow-up (4), intensity of FDG uptake is emerging as a valuable predictive factor regarding treatment outcome (5).