Diffusion-weighted Magnetic Resonance Imaging Examinations Research Articles

Apparent Diffusion Coefficient on Diffusion-Weighted Magnetic Resonance Imaging to Predict the Prognosis of Patients with Endometrial Cancer: A Meta-Analysis.

Apparent diffusion coefficient (ADC) derived from diffusion-weighted magnetic resonance imaging (DWI) may help diagnose endometrial cancer (EC). However, the association between ADC and the recurrence and survival of EC remains unknown. We performed a systematic review and meta-analysis to investigate whether pretreatment ADC on DWI could predict the prognosis of women with EC. PubMed, Embase, and Cochrane's Library were searched for relevant cohort studies comparing the clinical outcomes between women with EC having low versus high ADC on pretreatment DWI. Two authors independently conducted data collection, literature searching, and statistical analysis. Using a heterogeneity-incorporating random-effects model, we analyzed the results. In the meta-analysis, 1358 women with EC were included from eight cohort studies and followed for a median duration of 40 months. Pooled results showed that a low pretreatment ADC on DWI was associated with poor disease-free survival (DFS, hazard ratio [HR]: 3.29, 95% CI: 2.04 to 5.31, p < 0.001; I2 = 41%). Subgroup analysis according to study design, tumor stage, MRI Tesla strength, ADC cutoff, follow-up duration, and study quality score showed consistent results (p for subgroup analysis all > 0.05). The predictive value of low ADC for poor DFS in women with EC decreased in multivariate studies compared to univariate studies (HR: 2.59 versus 32.57, p = 0.002). Further studies showed that a low ADC was also associated with poor overall survival (HR: 3.36, 95% CI: 1.33 to 8.50, p = 0.01, I2 = 0). In conclusion, a low ADC on pretreatment DWI examination may predict disease recurrence and survival in women with EC.

Diffusion-Weighted MRI Findings of Caudate Nucleus and Putamen in Patients With Obsessive-Compulsive Disorder.

ObjectiveThe purpose of this study was to establish the diffusion-weighted magnetic resonance imaging (DW-MRI) findings of the caudate nucleus and putamen in patients with obsessive-compulsive disorder (OCD) and to obtain new information on the etiopathogenesis of OCD, which is still unclear.MethodsThe study comprised 20 patients with OCDs and 20 healthy volunteers. In these cases, DW-MRI and diffusion-weighted echo-planar images (DW-EPI) at b600 and b1000 gradient values were taken and the measurements were made using the apparent diffusion coefficient (ADC) maps of each group at b600 and b1000 values from the caudate nucleus and putamen.ResultsWhen the DW-MRI examination in patients with OCD was compared with the control group, the mean ADC values in the caudate nucleus and putamen were not found to have statistically significantly changed. In addition, there were no significant differences regarding the right and left caudate nuclei and putamen ADC values at the b600 and b1000 in the patients with OCD or the control group.ConclusionThere are still many unknowns about the neurobiology of OCD. When the DW-MRI examination of the patients with OCD was compared with the control group in our study, no significant difference was found between the ADC values of the caudate nucleus and putamen. Further studies are required for this present study on DW-MRI in patients with OCD to be meaningful.

Apparent diffusion coefficient measurement of the parotid gland parenchyma.

The measurements of apparent diffusion coefficient (ADC) with diffusion weighted magnetic resonance imaging (DW-MRI) is becoming a popular diagnostic and research tool for examination of parotid glands. However, there is little agreement between the reported ADC values of the parotid gland in published literature. In this review 43 studies on ADC measurement of the parotid glands were included. The analyses indicated several possible culprits of the observed ADC discrepancies. For example, DW-MRI examinations under gustatory stimulation gives higher ADC values compared to the unstimulated parotid gland (P=0.003). The diffusion weighting factors (b-values) can either increase (b-value <200 s/mm2) or decrease ADC values (b-values >1,000 s/mm2). The timing of follow-up DW-MRI after radiotherapy (RT) indicates correlation to the found ADC values (R2 =0.39). Interestingly, the choice of regions of interest (ROI) appears not to affect the measurements of ADC (P=0.75). It can be concluded that there is a critical need for standardization of ADC measurement of the parotid glands to allow valid inter-study comparisons and eventually to reach consensus on the use of ADC as biomarker.

Diffusion-weighted magnetic resonance imaging of mandibular bone marrow: do apparent diffusion coefficient values of the cervical vertebrae and mandible correlate with age?

The objective of this investigation was to assess the correlation between the mandible and cervical vertebrae bone marrow apparent diffusion coefficient (ADC), obtained by diffusion-weighted magnetic resonance imaging (DWI), with age; to verify the correlation between ADC values from the mandible and the cervical vertebrae; to describe and assess the differences between ADC values obtained from DWI examinations of distinct mandible areas as well as cervical vertebrae. Thirty imaging examinations with DWI for that included the mandible and C1, C2, C3, and C4 vertebrae in the same examination were included. ADC values were collected from 7 distinct areas in the mandible and the cervical vertebrae. Differences between ADC values and non-parametric correlations were performed. A total of 270 regions were assessed. No significant difference was found between ADC values of all areas tested. An inverse correlation was found between C2, C3, and C4 vertebrae ADC values and age. The significant correlation of anatomic area ADC values and age were presented as graphics to verify if the linear trend of ADC values and age are in accordance with the literature CONCLUSIONS: The mandible area that most correlates with the cervical vertebrae, using ADC values, is the posterior trabecular area, below the inferior molars. Also, C2, C3, and C4 vertebrae ADC values inversely correlate with age, which demonstrates the bone qualitative changes in bone composition. ADC values may be useful for the qualitative assessment of bone quality to screen patients at osteoporosis risk.

Cerebral Embolism After Transcarotid Transcatheter Aortic Valve Replacement: Factors Associated With Ipsilateral Ischemic Burden

Transcarotid transcatheter aortic valve replacement (TAVR) recipients may be exposed to a higher ipsilateral subclinical cerebral ischemic burden compared with the contralateral hemisphere. We sought (1) to compare the cerebral ischemic burden of the 2 hemispheres after transcarotid TAVR, as evaluated by diffusion weighted-magnetic resonance imaging (DW-MRI), and (2) to identify the factors associated with ipsilateral ischemic burden. This prospective study included 52 patients undergoing transcarotid TAVR, followed by a DW-MRI examination. All DW-MRIs were analyzed offline by a radiologist blinded to the clinical data. TAVR was performed through the left (n= 50) or right (n= 2) carotid artery. Procedural success was achieved in all patients, carotid dissection requiring patch closure occurred in 1 patient, and there were no periprocedural stroke events. At least 1 cerebral ischemic lesion was identified in the ipsilateral and contralateral hemisphere in 84.6% and 63.5% of patients, respectively (P= .005), and the number of ischemic lesions per patient was higher in the ipsilateral vs the contralateral hemisphere (2 [interquartile range, 1-5] vs 1 [interquartile range, 0-3], P= .005). The lesion volume (per lesion) and the average lesion volume (per patient) did not differ between the 2 hemispheres. A larger sheath/catheter size (≥18F vs ≤16F) was associated with a higher ipsilateral ischemic burden (P= .026). Carotid artery access for TAVR was associated with a higher number of cerebral ischemic lesions in the ipsilateral (vs contralateral) cerebral hemisphere. The use of a larger sheath/delivery system (≥18F) was associated with an increased ipsilateral ischemic burden.

Response Evaluation of Choroidal Melanoma After Brachytherapy Using Diffusion-Weighted Magnetic Resonance Imaging (DW-MRI): Preliminary Findings.

Purpose: To evaluate the role of diffusion-weighted magnetic resonance imaging (DW-MRI) in the assessment of therapeutic response in patients with choroidal melanoma treated with brachytherapy.Materials and Methods: We performed a prospective, unicentric study which included patients with choroidal melanoma and indication for brachytherapy. Three DW-MRI examinations were proposed for each patient, one before and two after treatment. The apparent diffusion coefficient (ADC) value was calculated on DW-MRI and compared with local tumor control assessed by ophthalmologic follow-up.Results: From 07/2018 to 06/2019, 19 patients were recruited, 13 of whom underwent follow-up examinations. Patients' ages ranged from 24 to 78 years and 52.9% were male. At the ocular ultrasound, the mean tumor thickness and diameter were 6.3 and 11.5 mm, respectively. Two patients (15.4%) showed signs of tumor progression during follow-up (7 and 9 months after treatment). There was no statistically significant difference in tumor size between MR before and after treatment, however, there was a significant reduction in mean ADC in patients with progression (p = 0.02).Conclusion: DW-MRI is a promising method for monitoring patients with choroidal melanoma; reduction in the mean ADC values between pre-treatment MRI and the first post-treatment MRI may be related to the lack of response to brachytherapy and increased risk of disease progression.

Diffusion weighted imaging is a promising method to detect acute pyelonephritis in non-sedated free breathing infants

Urinary tract infection (UTI) is a common disease in infants. The initial evaluation includes imaging to identify risk factors for permanent renal damage, such as malformation and renal parenchymal involvement of the infection i.e. pyelonephritis. 99mTc-Dimercaptosuccinic acid (DMSA) scintigraphy is a well-established method for detection of pyelonephritis and renal damage, but has limitations in availability, spatial resolution, and detection of congenital malformations. Diffusion weighted magnetic resonance imaging (DWI) has been shown to have a high sensitivity for detection of pyelonephritis in children without the use of invasive procedures, contrast agents or ionizing radiation. How this method performs in young infants during non-sedated free breathing remains, however, to be investigated. To prospectively assess the feasibility and performance of DWI for detection of pyelonephritis in non-sedated free breathing infants. 32 children <6 months of age with first-time symptomatic UTI were examined with DWI and DMSA scintigraphy. The DWI examination was performed using a free breathing protocol without the use of sedation. Pyelonephritic lesions were registered for both methods by independent observers. Agreement between DWI and DMSA was evaluated. Consensus diagnosis was determined and compared to the DWI findings. The MRI and DMSA examinations were completed in 25 infants, with a median age of 1.7 (0.7-5.5) months. Focal uptake reductions were detected on the DMSA images in 12 (24%) of the 50 kidneys. The DWI method demonstrated a fair to good agreement with DMSA, k=0.50 (p<0.0001). The consensus diagnosis was pyelonephritis in eight (16%) of the 50 kidneys. DWI detected seven of the eight kidneys with pyelonephritis. No false positive findings were detected with DWI compared to consensus diagnosis. This study has shown an agreement between DWI and DMSA scintigraphy in the detection of pyelonephritis. Further validation of the performance of DWI, using a consensus diagnosis as a reference, confirmed the potential of the method. This feasibility study included a limited number of patients and the results need to be confirmed in a prospective study of a larger cohort. Free breathing DWI is a promising method for detection of pyelonephritic lesions in non-sedated infants.

Diffusion-weighted MRI, 11C-choline PET/CT, and 18F-FDG PET/CT for predicting the Gleason score in prostate cancer.

To evaluate diffusion-weighted magnetic resonance imaging (DWI), 11C-choline positron emission tomography (PET), and fluorine-18-fluorodeoxyglucose (18F-FDG) PET for predicting Gleason score in prostate cancer patients. The study cohort included 11 patients with biopsy-proven prostate cancer who underwent DWI, 11C-choline PET, and 18F-FDG PET examinations before treatment. The correlations of Gleason score with those findings were determined using Spearman's test. Multi-technique imaging performance for separating higher Gleason score (≥8) cases was also examined. Both diffusion coefficient (ADC) map and 11C-choline PET/computed tomography (CT) findings showed prostate cancer in all 11 patients, while 18F-FDG PET/CT was only successful in 6 (54.5%) cases, thus no further evaluations of that modality were performed. A moderately negative correlation was observed between Gleason score and ADC value for the primary tumor shown by DWI, though the difference was not significant (r=-0.49, P=0.13). In contrast, a strongly significant positive correlation was observed between Gleason score and maximum standardized uptake value (SUVmax) for the primary tumor in 11C-choline PET findings (r=0.85, P=0.0010). Sensitivity, specificity, and accuracy for separating higher (≥8) from lower (≤7) Gleason score were 87.5%, 33.3%, and 72.7%, respectively, with a best cut-off value of 0.78 for ADC map, and 87.5%, 100%, and 90.9%, respectively, with a best cut-off value of 6.0 for 11C-choline PET. Carbon-11-choline PET was found have a greater correlation with Gleason score than DWI and is considered to be more useful to predict a higher score in patients with prostate cancer. Fluorine-18-FDG PET was limited because of low sensitivity.

Apparent Diffusion Coefficient Value Changes of Normal Uterine Cervix with Aging

Background: In the magnetic resonance imaging (MRI) of many tissues, apparent diffusion coefficient (ADC) values vary with age. In the literature, there are no studies in which normal cervix ADC values and their relationship with age is analyzed. Objectives: To evaluate whether changes occur in ADC values with aging in the uterine cervix with 3-Tesla MRI. Patients and Methods: Female patients aged between 18 and 70 years who were found to have lower abdominal diffusion-weighted magnetic resonance imaging (DWI) in the radiology database from December 2017 to May 2018 were evaluated. All DWI examinations were performed using a 3-T MR with 2 b values (b = 50, 800 s/mm2). A total of 161 patients were divided into two groups according to their menopausal status (premenopausal n = 106, postmenopausal n = 55). To evaluate the correlation between the age of the patient and the ADC values, Pearson correlation analysis was performed. Results: The mean age of the patients was 41.4 ± 11.6 years. The mean ADC value was 1.276 ± 0.25 mm2/sec × 10-3 in the whole population. There was a negative correlation between age and ADC values. The mean cervix ADC value of premenopausal and postmenopausal patients was 1.333 ± 0.23 mm2/sec × 10-3 and 1.165 ± 0.25 mm2/sec × 10-3, respectively. There was a statistically significant difference between the groups in term of cervix ADC value (P < 0.05). Conclusion: A negative correlation between aging and ADC values was found. Menopausal status has an effect on the ADC values of the cervix. These findings may indicate cellular and extracellular matrix changes in the cervix tissue with aging and menopausal status.

Investigation of Using Diffusion-Weighted Magnetic Resonance Imaging (DWI) Combined with CT and Esophagogram to Evaluate the Therapeutic Effect of Esophageal Squamous Cell Carcinoma (ESCC) Treated with Chemoradiotherapy

To investigate the application value of using DWI combined with CT and esophagogram evaluating the therapeutic effect of ESCC treated with chemoradiotherapy (CCRT). From January 2004 to December 2015, 529 patients with ESCC underwent CCRT were enrolled. Therapeutic effect was evaluated based on the maximal esophageal wall thickness measured by CT, hyperintense expression in DWI and tumor shape changes in esophagogram. Prognosis analysis was also performed. A total of 529 patients were evaluated by esophagogram and CT -based evaluation criteria, 132 patients were in complete response (CR) and 385 in partial response (PR) after CCRT. Overall survival (OS) and local control (LC) rates of patients in CR were significantly higher than those in PR, with the 5-, 10-year OS at 37%, 30% versus 21%, 19%, respectively (P<0.001). The median survival time was 5 months for 12 patients in none response (NR). Of all enrolled patients, 83 patients received DWI examination before and after CCRT. A total of 48 patients had no hyperintense expression in DWI (defined as CR) after CCRT and 35 still had hyperintense expression (defined as PR). OS and LC rates of patients received DWI examination in CR were significantly higher than those in PR (P=0.013, 0.001). In contrast, there was a trend towards increased uncontrolled and recurrent rate of patients in PR versus CR (P<0.05). According to the evaluation criteria based on DWI combined with CT and esophagogram, OS and LC rates of patients in CR were significantly higher than those in PR, with the 5-year LC at 62% versus 33% and 5-year OS at 48% versus 16%, respectively (P=0.018, 0.002). The esophagogram and CT -based evaluation criteria can accurately evaluate the therapeutic effect and predict prognosis in patients with ESCC. The expression of hyperintense in DWI at the end of treatment may indicate a high risk of recurrence. The therapeutic effect evaluated by DWI combined with CT and esophagogram maybe more objective and more accurate.

Diffusion-weighted magnetic resonance imaging is useful for the response evaluation of chemotherapy and/or radiotherapy to recurrent lesions of lung cancer

Diffusion-weighted magnetic resonance imaging (DWI) has been reported to be useful for the assessment of lung cancer staging. It is uncertain whether DWI is more accurate for the response evaluation of chemotherapy and/or radiotherapy compared to computed tomography (CT). The purpose of this study is to compare the response evaluation of DWI for chemotherapy and/or radiotherapy to recurrent tumors of lung cancer with that of CT which is a standard tool in RECIST (Response Evaluation Criteria in Solid Tumours). Forty-one patients who agreed to this project and had CT scan and DWI examinations within a month of each other every six months for at least 2 years after pulmonary resection of primary lung cancer were enrolled in this study. Of the patients, 24 patients had metastases or recurrences, and CT and DWI were performed for assessment of the response evaluation of chemotherapy and/or radiotherapy to recurrent lesions. They were followed up for at least two years after the relapse. The response evaluation by CT using RECIST were PR in five patients, SD in two, and PD in the remaining 17 patients. On the other hand, the response evaluation by DWI were CR in four patients, PR in two patients, SD in one, and PD in the remaining 17 patients. Follow-up studies revealed the response evaluation by DWI were correct. Functional evaluation of DWI is better than that of CT for the response evaluation of chemotherapy and/or radiotherapy to recurrent tumors of lung cancer.

Contribution of diffusion weighted MRI to diagnosis and staging in gastric tumors and comparison with multi-detector computed tomography.

BackgroundDiagnostic performance of Diffusion-Weighted magnetic resonance Imaging (DWI) and Multi-Detector Computed Tomography (MDCT) for TNM (Tumor, Lymph node, Metastasis) staging of gastric cancer was compared.Patients and methodsWe used axial T2-weighted images and DWI (b-0,400 and b-800 s/mm2) protocol on 51 pre-operative patients who had been diagnosed with gastric cancer. We also conducted MDCT examinations on them. We looked for a signal increase in the series of DWI images. The depth of tumor invasion in the stomach wall (tumor (T) staging), the involvement of lymph nodes (nodal (N) staging), and the presence or absence of metastases (metastatic staging) in DWI and CT images according to the TNM staging system were evaluated. In each diagnosis of the tumors, sensitivity, specificity, positive and negative accuracy rates of DWI and MDCT examinations were found through a comparison with the results of the surgical pathology, which is the gold standard method. In addition to the compatibilities of each examination with surgical pathology, kappa statistics were used.ResultsSensitivity and specificity of DWI and MDCT in lymph node staging were as follows: N1: DWI: 75.0%, 84.6%; MDCT: 66.7%, 82%;N2: DWI: 79.3%, 77.3%; MDCT: 69.0%, 68.2%; N3: DWI: 60.0%, 97.6%; MDCT: 50.0%, 90.2%. The diagnostic tool DWI seemed more compatible with the gold standard method (surgical pathology), especially in the staging of lymph node, when compared to MDCT. On the other hand, in T staging, the results of DWI and MDCT were better than the gold standard when the T stage increased. However, DWI did not demonstrate superiority to MDCT. The sensitivity and specificity of both imaging techniques for detecting distant metastasis were 100%.ConclusionsThe diagnostic accuracy of DWI for TNM staging in gastric cancer before surgery is at a comparable level with MDCT and adding DWI to routine protocol of evaluating lymph nodes metastasis might increase diagnostic accuracy.

Diagnostic value of diffusion weighted MRI and ADC in differential diagnosis of cavernous hemangioma of the liver.

To investigate the use of diffusion weighted magnetic resonance imaging (DWI) and the apparent diffusion coefficient (ADC) values in the diagnosis of hemangioma. The study population consisted of 72 patients with liver masses larger than 1 cm (72 focal lesions). DWI examination with a b value of 600 s/mm2 was carried out for all patients. After DWI examination, an ADC map was created and ADC values were measured for 72 liver masses and normal liver tissue (control group). The average ADC values of normal liver tissue and focal liver lesions, the "cut-off" ADC values, and the diagnostic sensitivity and specificity of the ADC map in diagnosing hemangioma, benign and malignant lesions were researched. Of the 72 liver masses, 51 were benign and 21 were malignant. Benign lesions comprised 38 hemangiomas and 13 simple cysts. Malignant lesions comprised 9 hepatocellular carcinomas, and 12 metastases. The highest ADC values were measured for cysts (3.782±0.53×10(-3) mm(2)/s) and hemangiomas (2.705±0.63×10(-3) mm(2)/s). The average ADC value of hemangiomas was significantly higher than malignant lesions and the normal control group (p<0.001). The average ADC value of cysts were significantly higher when compared to hemangiomas and normal control group (p<0.001). To distinguish hemangiomas from malignant liver lesions, the "cut-off" ADC value of 1.800×10(-3) mm(2)/s had a sensitivity of 97.4% and a specificity of 90.9%. To distinguish hemangioma from normal liver parenchyma the "cut-off" value of 1.858×10(-3) mm(2)/s had a sensitivity of 97.4% and a specificity of 95.7%. To distinguish benign liver lesions from malignant liver lesions the "cut-off" value of 1.800×10(-3) mm(2)/s had a sensitivity of 96.1% and a specificity of 90.0%. DWI and quantitative measurement of ADC values can be used in differential diagnosis of benign and malignant liver lesions and also in the diagnosis and differentiation of hemangiomas. When dynamic examination cannot distinguish cases with vascular metastasis and lesions from hemangioma, DWI and ADC values can be useful in the primary diagnosis and differential diagnosis. The technique does not require contrast material, so it can safely be used in patients with renal failure.

A comparative study of computed tomography and magnetic resonance imaging in pathological diagnosis of regional lymph node metastasis

Objective To evaluate the efficacy of computed tomography (CT) and diffusion-weighted magnetic resonance imaging (DWMRI) in the diagnosis of regional lymph node metastasis in thoracic carcinoma, and to figure out the methods and thresholds for delineation of lymph nodes with higher reasonability and accuracy. Methods A total of 43 patients with thoracic carcinoma, including 35 patients with esophageal cancer and 8 patients with non-small cell lung cancer, were enrolled as subjects from 2012 to 2013. All patients received abdominal CT scan and DWMRI examination one week before surgery, and regional lymph node metastasis was diagnosed based on the images of CT scan or DWMRI. With the postoperative pathology as the gold standard, the diagnostic efficacy was evaluated and compared between the two methods. The two sets of obtained images were analyzed using the χ2-test. Results The sensitivity, specificity, accuracy, positive predictive value, negative predictive value, and Youden’s index of CT versus DWMRI in the diagnosis of regional lymph node metastasis were 57.1% vs. 60.0%, 96.3% vs. 98.9%, 93.8% vs. 96.5%, 50.0% vs. 77.8%, 97.2% vs. 97.4%, and 53.4% vs. 58.9%, respectively; the specificity, accuracy, and positive predictive value of DWMRI were significantly superior to those of CT (P=0.005, 0.038, 0.022). Twenty out of forty lymph nodes diagnosed by CT scan were false positive, and 15(75%) of them could be corrected by DWMRI. Fifteen out of forty lymph nodes diagnosed by CT scan were false negative, and 3(20%) of them could be recognized by DWMRI. In all 35 metastatic lymph nodes, 5 lymph nodes had no apparent swelling on images, and 13(43.3%) out of the other 30 lymph nodes had a short diameter less than 1.0 cm. Conclusions CT scan has apparent limitation in the diagnosis of regional lymph node metastasis. Many metastatic lymph nodes would be missed if a short diameter not less than 1.0 cm is the only standard for target volume delineation. With superior specificity, accuracy, and positive predictive value to CT in the diagnosis of regional lymph node metastasis, DWMRI can effectively rule out non-cancerous intumescent lymph nodes and recognize some of small metastatic lymph nodes. Key words: Diffusion-weighted magnetic resonance imaging; Tomography, X-ray computed; Lymph node pathology; Esophageal neoplasms; Lung neoplasm

MRI and CT diagnosis of pilomyxoid astrocytoma

Objective To investigate the MRI and CT manifestations of pilomyxoid astrocytoma (PMA). Methods The MRI and CT findings of 39 patients with PMA confirmed by surgical pathology at the Department of Neuroradiology, Beijing Tiantan Hospital, Capital Medical University from September 2010 to August 2014 were analyzed retrospectively. Nineteen of them were males and 20 were females. The age ranged from 10 months to 47 years. Results There were 25 patients with PMA in the hypothalamic/chiasmatic region. Their median age of onset was 5.83. The mean maximum diameter of the foci was 47.44 mm. There was no obvious peritumoral edema; however, they had varying degrees of hydrocephalus. The banding hypointensities were observed on T2WI in 14 patients. The solid components of PMA showed intralesional multiple-ring enhancement in 22 patients. Diffusion weighted magnetic resonance imaging (DWI) of 3 patients showed that the diffusion was not restricted, and 9 of them showed subarachnoid dissemination. CT examination revealed that 6 patients had calcification and 1 had bleeding. There were 14 patients in the non-hypothalamic/chiasmatic region; their median age of onset was 17. The mean maximum diameter of the foci was 39.43 mm; 6 patients had mild peritumoral edema and 3 had mild hydrocephalus. The banding hypointensities were observed in the hyperintensities on T2WI in 6 patients. The foci of 11 patients showed obviously enhanced. The enhancement pattern was enhancement of mural nodule in cystic foci. DWI examination revealed that the diffusion was not restricted in 1 case. No subarachnoid dissemination was observed. Magnetic resonance spectroscopy (MRS) examination was performed in 3 cases; the solid components of the foci met the MRS spectral lines of general glioma. CT examination revealed that 2 patients had calcification and 2 had bleeding. Conclusions PMA may occur in all parts of the brain. It shows a cystic and solid mass. The solid components can be enhanced obviously. The age of onset in the hypothalamic/chiasmatic region is younger and subarachnoid dissemination is common. The age of onset in the non-hypothalamic/chiasmatic region is older. The stellate enhancement of mural nodule after enhancement has more characteristics. Key words: Astrocytoma; Brain neoplasms; Tomography, X-ray computed; Magnetic resonance imaging

Role of diffusion-weighted MRI in acute pyelonephritis: a prospective study

Imaging is vital in diagnosis of complicated pyelonephritis and has been traditionally performed by computed tomography (CT). However, CT with contrast agents cannot be performed in patients with renal failure. Diffusion-weighted (DW) magnetic resonance imaging (MRI) has the potential to overcome this disadvantage. To prospectively evaluate the accuracy of quantitative apparent diffusion coefficient (ADC) values to differentiate nephritis from renal abscesses in patients with pyelonephritis. Forty-two patients with clinical and laboratory diagnosis of pyelonephritis underwent CT and DW MRI examinations. Diffusion images were obtained by using a non-breath-hold, single-shot echo-planar sequence with b values of 0, 600, and 1000 s/mm(2). Circular regions of interest were places on areas of nephritis, normal renal parenchyma, and renal abscesses as localized by CT and DW MRI images to obtain the ADC values of each of these regions. The ADC values of these three different tissue types were statistically compared using the one-way analysis of variance test for statistical significance. A P value <0.05 was considered to be statistically significant. For the diagnosis of pyelonephritis, DW MRI had a higher sensitivity of 95.3% as compared to that of non-contrast CT (66.7%) and contrast-enhanced CT (88.1%). Areas of nephritis had significantly lower ADC values (P < 0.001) than the normal renal cortical parenchyma. Also, renal abscesses had significantly lower ADC values (P < 0.001) than areas of nephritis. However, CT is more useful for the diagnosis of renal calculi and emphysematous pyelonephritis. ADC values derived from the diffusion sequence have significantly lower values in renal abscesses than in areas of nephritis.

Management of free-floating thrombus within the arcus aorta and supra-aortic arteries

IntroductionClinical management strategy and the best treatment option of free floating thrombus (FFT), detected in patients with acute ischemic cerebrovascular diseases is still uncertain due to the rarity of these conditions. Recent studies emphasize that FFT within cerebral vessels may not be a surgical emergency since complete dissolution without any further neurologic progression occurred in 86% of patients treated medically.The aim of this study was to investigate the effect of medical treatment on the fate of thrombus and the clinical status in acute cerebrovascular event patients with detected FFT in the artery feeding the compromised brain territory at the time of diagnosis. Materials and methodsWe have retrospectively reviewed the initial and follow up computed tomography angiography, diffusion-weighted magnetic resonance imaging examinations of 37 acute ischemic stroke patients with detected FFT and treated medically. The patients were evaluated for any change of the FFT, residual stenosis after the FFT shrunk or disappeared and neurologic outcome. ResultsFFT was located in cervical carotid artery, intracranial artery and arcus aorta in 23, 6 and 5 of the patients respectively. Dissection accompanied the FFT in 3 patients. Recanalization was maintained in 34 patients however, three of them suffered from new infarctions. A total occlusion was detected in three patients. Two of them had new infarcts while one was stable during clinical follow-up period. ConclusionThe results of our retrospective study have shown that FFT in the proximal aorta and supra-aortic arteries tend to resolve with anticoagulant and/or antiplatelet treatment without causing recurrent adverse events in most of the cases. Furthermore, resolution of the clot seems to provide a safer ground for a recanalization procedure like stenting or endarterectomy if needed.

Investigation of Using Diffusion-Weighted Magnetic Resonance Imaging to Evaluate the Therapeutic Effect of Esophageal Carcinoma Treatment

Aim: To explore the associations of diffusion-weighted magnetic resonance imaging (DWI) measurements with the therapeutic effect (TE) on and survival of esophageal carcinoma patients treated with chemoradiotherapy (CRT). Methods: From March 2010 to December 2011, 77 patients were prospectively enrolled into a cohort study. DWI was performed at the beginning and 1-3 months after CRT. The immediate post-CRT TE was evaluated according to the Response Evaluation Criteria in Solid Tumors (RECIST). The associations between the disappearance status of hyperintense expression (HE) in DWI and the apparent diffusion coefficient (ADC) of DWI with the complete response (CR) as TE and survival were analyzed. Results: 3 patients were excluded due to the absence of HE in DWI. Analysis of the remaining 74 patients indicated that their ADC values were significantly improved from 1.64 ± 0.48 to 2.65 ± 0.58 mm²/s from pre-CRT to post-CRT (p = 0.000). Both univariate and multivariate Cox model analyses showed that high post-CRT ADC values and the disappearance status of HE associated significantly with the TE (CR rate) and survival. Conclusions: DWI examination could afford useful markers to predict the treatment response as well as the survival of patients with esophageal squamous cell carcinoma. The non-disappearance of HE in DWI and low ADC values after CRT were risk factors.

Can diffusion-weighted magnetic resonance imaging (DW-MRI) alone be used as a reliable sequence for the preoperative detection and characterisation of hepatic metastases? A meta-analysis

PurposeTo perform a meta-analysis of all available studies of the diagnostic performance of diffusion-weighted magnetic resonance imaging (DW-MRI) in patients with hepatic metastases. MethodsDatabases including MEDLINE and EMBASE were searched for relevant original articles published from January 2000 to February 2012. We determined sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR–), diagnostic odds ratio (DOR) and constructed summary receiver operating characteristic curves using hierarchical regression models. ResultsAcross 11 studies (537 patients), DW-MRI sensitivity was 0.87 (95%confidence interval (CI), 0.80, 0.91) and specificity was 0.90 (95%CI, 0.86, 0.93). Overall, LR+ was 8.52 (95%CI, 6.17, 11.77), LR– was 0.15 (95%CI, 0.10, 0.22) and DOR was 57.36 (95%CI, 38.29, 85.93). In studies in which both DW-MRI and contrast-enhanced magnetic resonance imaging (CE-MRI) were performed, the comparison of DW-MRI performance with that of CE-MRI suggested no major differences against these two methods (p>0.05). DW-MRI combined CE-MRI had higher sensitivity and specificity than DW-MRI alone (97% versus 86% and 91% versus 90%, respectively) (p<0.05). The subgroup in which DW-MRI examinations were performed with a 3.0Tesla (T) device had higher pooled specificity (0.91, 95%CI, 0.88–0.95) than the subgroup of DW-MRI with 1.5T device (0.81, 95%CI, 0.67, 0.94) (p<0.05). Average lesion size (⩽1.5cm versus >1.5cm) did not influence the diagnostic accuracy of the test (p>0.05). ConclusionOur results demonstrate DW-MRI has good diagnostic performance in the overall evaluation of hepatic metastases and equivalent to CE-MRI. Combination of CE-MRI and DW-MRI can improve the diagnostic accuracy of magnetic resonance (MR) imaging. Our study further confirms that DW-MRI can accurately detect hepatic metastases regardless of the lesion size. It is suggested to perform DW-MRI by 3.0T devices, which might have high specificity to identify liver metastases.

Diffusion-weighted magnetic resonance imaging of the normal endometrium: temporal and spatial variations of the apparent diffusion coefficient

Diffusion-weighted magnetic resonance imaging (DWI) is increasingly used in the diagnosis of endometrial disease. No complete knowledge, however, exists yet of the influence of physiology on the endometrial apparent diffusion coefficient (ADC) values on which DWI is based. To establish whether the ADC values measured with DWI in the endometrium of healthy reproductive-aged women significantly vary from the early proliferative to the periovulatory phase of the menstrual cycle and between the fundus and the isthmus of the uterus. In 17 women the endometrial ADC values measured on the fifth menstrual day, both at the fundus and at the isthmus of the uterus, were compared to the values obtained on the 14th day before the subsequent cycle. In 81 women (menstrual day: fifth through 21st) the endometrial ADC values measured at the fundus were compared to the values obtained at the isthmus of the uterus. All examinations were performed with a 1.5 T magnet (b values: 0 and 800 mm/s(2)). The results were analyzed by means of Student's t-test per paired data. The endometrial ADC values measured on the fifth day of the menstrual cycle were lower than those obtained in the periovulatory phase both at the fundus (mean 0.923 vs. 1.256 × 10(-3) mm(2)/s) and at the isthmus (mean 1.297 vs. 1.529 × 10(-3) mm(2)/s) of the uterus. The endometrial ADC values measured at the fundus of the uterus were lower than those obtained at the isthmus (mean 1.132 vs. 1.420 × 10(-3) mm(2)/s) through the menstrual cycle. All these differences were highly significant (P < 0.001) at statistical analysis. Physiological variations occurring in endometrial ADC values of healthy women should be considered by the radiologists when interpreting DWI examinations in patients with endometrial disease.