Three-Dimensional Magnetic Resonance Imaging Fast Field Echo Resembling a Computed Tomography Using Restricted Echo-Spacing Sequence Is Equivalent to 3-Dimensional Computed Tomography in Quantifying Bone Loss and Measuring Shoulder Morphology in Patients With Shoulder Dislocation.

PURPOSE: To evaluate the equivalence of 3-dimensional (3D) magnetic resonance imaging (MRI) (FRACTURE [Fast field echo Resembling A CT Using Restricted Echo-spacing]) and 3D computed tomography (CT) in quantifying bone loss in patients with shoulder dislocation and measuring morphologic parameters of the shoulder. METHODS: From July 2022 to June 2023, patients with anterior shoulder dislocation who were aged 18 years or older and underwent both MRI and CT within 1 week were included in the study. The MRI protocol included an additional FRACTURE sequence. Three-dimensional reconstructions of MRI (FRACTURE) and CT were completed by 2 independent observers using Mimics software (version 21.0) through simple threshold-based segmentation. For bone defect cases, 2 independent observers evaluated glenoid defect, percentage of glenoid defect, glenoid track, Hill-Sachs interval, and on-track/off-track. For all cases, glenoid width, glenoid height, humeral head-fitting sphere radius, critical shoulder angle, glenoid version, vault depth, and post-processing time were assessed. The paired t test was used to assess the differences between 3D CT and 3D MRI (FRACTURE). Bland-Altman plots were constructed to evaluate the consistency between 3D CT and 3D MRI (FRACTURE). Interobserver and intraobserver agreement was evaluated with the interclass correlation coefficient. The paired χ2 test and Cohen κ statistic were used for binary variables (on-track/off-track). RESULTS: A total of 56 patients (16 with bipolar bone defect, 5 with only Hill-Sachs lesion, and 35 without bone defect) were ultimately enrolled in the study. The measurements of 21 bone defect cases showed no statistically significant differences between 3D CT and 3D MRI: glenoid defect, 4.05 ± 1.44 mm with 3D CT versus 4.16 ± 1.39 mm with 3D MRI (P = .208); percentage of glenoid defect, 16.21% ± 5.95% versus 16.61% ± 5.66% (P = .199); glenoid track, 18.02 ± 2.97 mm versus 18.08 ± 2.98 mm (P = .659); and Hill-Sachs interval, 14.29 ± 1.93 mm versus 14.35 ± 2.07 mm (P = .668). No significant difference was found between 3D CT and 3D MRI in the diagnosis of on-track/off-track (P > .999), and diagnostic agreement was perfect (κ = 1.00, P < .001). There were no statistically significant differences between the 2 examination methods in the measurements of all 56 cases, except that the post-processing time of 3D MRI was significantly longer than that of 3D CT: glenoid height, 34.56 ± 1.98 mm with 3D CT versus 34.67 ± 2.01 mm with 3D MRI (P = .139); glenoid width, 25.32 ± 1.48 mm versus 25.45 ± 1.47 mm (P = .113); humeral head-fitting sphere radius, 22.91 ± 1.70 mm versus 23.00 ± 1.76 mm (P = .211); critical shoulder angle, 33.49° ± 2.55° versus 33.57° ± 2.51° (P = .328); glenoid version, -3.25° ± 2.57° versus -3.18° ± 2.57° (P = .322); vault depth, 37.43 ± 1.68 mm versus 37.58 ± 1.75 mm (P = .164); and post-processing time, 89.66 ± 10.20 seconds versus 360.93 ± 26.76 seconds (P < .001). For all assessments, the Bland-Altman plots showed excellent consistency between the 2 examination methods, and the interclass correlation coefficients revealed excellent interobserver and intraobserver agreement. CONCLUSIONS: Three-dimensional MRI (FRACTURE) is equivalent to 3D CT in quantifying bone loss in patients with shoulder dislocation and measuring shoulder morphologic parameters. LEVEL OF EVIDENCE: Level II, development of diagnostic criteria (consecutive patients with consistently applied reference standard and blinding).

ADC and kinetic parameter of primary tumor: Surrogate imaging markers for fertility-sparing vaginal radical trachelectomy in patients with stage IB cervical cancer.

PURPOSE: To investigate the role of ADC and kinetic parameters derived from DCE-MRI in selecting eligible candidates for fertility-sparing vaginal radical trachelectomy (VRT). METHOD: Female patients with FIGO stage IB cervical cancers between March 2019 and January 2022 were retrospectively included. All patients underwent hysterectomy and bilateral lymphadenectomy. According to the surgical pathology, the study population was divided into VRT-eligible group and VRT-ineligible group. ADC, semi-quantitative and quantitative kinetic parameters of the primary tumor were compared between the two groups. Logistic regression analysis was used to determine the independent predictors for VRT eligibility and ROC curve was used to evaluate the predictive performance. RESULTS: 19 patients were deemed eligible for VRT and 50 were ineligible. Compared with VRT-eligible group, time to peak and ADC were significantly lower in VRT-ineligible group (P = 0.004 and 0.001, respectively) while volume fraction of plasma (Vp) was higher in VRT ineligible group (P = 0.001). ADC and Vp were independent predictors for VRT eligibility. Combining Vp and ADC yielded the highest area under the ROC curve of 0.853 compared with that of 0.766 for Vp and 0.764 for ADC, though marginal differences were found (P = 0.109 and 0.078, respectively). CONCLUSIONS: ADC and the kinetic DCE-MRI parameter Vp can be used as surrogate markers to select eligible candidates for fertility-sparing VRT.

Quantification of pancreatic iron overload and fat infiltration and their correlation with glucose disturbance in pediatric thalassemia major patients.

BACKGROUND: Diabetes mellitus affects more than a quarter of patients with thalassemia major (TM) worldwide, and increases the risk for cardiac complications, contributing to significant morbidity. Pancreatic iron overload (IO) and fat infiltration have been correlated with this endocrinal complication in adult TM patients. It has been shown that in adult TM patients, iron accumulation and fat infiltration are found to be heterogeneous in the pancreatic head, body, and tail region. R2* and a fat fraction (FF) generated by gradient-echo imaging can be used as quantitative parameters to assess the iron and fat contents of the pancreas. This study aimed to determine the pattern of pancreatic iron accumulation and fat infiltration in pediatric TM patients with gradient-echo imaging and evaluate the association between pancreatic IO and fat infiltration and glucose disturbances. METHODS: A total of 90 children with TM (10.7±3.1 years) were included. All patients underwent pancreatic magnetic resonance imaging (MRI) using multi-echo gradient-echo sequences. IO was measured by R2* relaxometry in 90 patients, and FF values were measured using iterative decomposition of water and fat with echo asymmetry and the least-squares estimation (IDEAL) method in 40 patients. R2* and FF were assessed in the pancreatic head, body, and tail. The global R2* and global FF values were obtained by averaging the respective values from the pancreatic head, body, and tail. The correlations between global R2*, global FF, and fasting glucose were determined using Spearman's correlation analysis. The Friedman test was used to compare R2* and FF among different pancreatic regions. Receiver operating characteristic (ROC) analysis was used to determine the performance of global R2* and global FF in discriminating impaired fasting glucose from normal fasting glucose patients. RESULTS: The global R2* was positively correlated with the global FF in the pancreas (r=0.895, P<0.001). No significant differences were found in R2* among the 3 regions of the pancreas (χ2=4.050, P=0.132), but significant differences were found in FF among the 3 pancreatic regions (χ2=16.350, P<0.001). Both global pancreatic R2* (r=0.408, P<0.001) and global FF (r=0.523, P=0.001) were positively correlated with fasting glucose. ROC analysis showed that global pancreatic R2* and global FF had an area under the curve of 0.769 and 0.931 (both P<0.001), respectively, in discriminating between impaired and normal glucose function patients. CONCLUSIONS: Pediatric TM patients can have homogeneous iron siderosis and heterogeneous fat infiltration in the pancreas as measured by gradient-echo imaging, both of which are risk factors for diabetes.

Quantitative kinetic parameters of primary tumor can be used to predict pelvic lymph node metastasis in early-stage cervical cancer.

PURPOSE: To investigate the role of kinetic parameters of primary tumor derived from dynamic contrast-enhanced MRI (DCE-MRI) in predicting pelvic lymph node metastasis (PLNM) in patients with cervical cancer. METHODS: 66 women with newly diagnosed cervical cancer were included between July 2017 and August 2019. All patients had a FIGO stage IB-IIA cancer and treated with hysterectomy and bilateral lymphadenectomy. Kinetic parameters of the primary tumor were derived from DCE-MRI data. The tumor diameter, ADC value, kinetic parameters, and nodal short-axis diameter were compared between patients with or without PLNM. Logistic regression analysis was used to determine the independent predictors for PLNM and receiver operator characteristic curve was used to evaluate the predictive performance. RESULTS: There were 20 patients with PLNM and 46 patients without PLNM. Tumor diameter, the efflux rate constant (Kep), and nodal short-axis diameter were significantly higher in patients with PLNM (P < 0.01). Multivariate logistic regression analysis showed that Kep and short-axis diameter were independent predictors for PLNM. Combining Kep and nodal short-axis diameter yielded the highest area under the curve (AUC) of 0.839. Combined with Kep, the sensitivity, specificity, negative predictive value, and positive predictive value of nodal short-axis diameter increased from 0.500, 0.957, 0.815, and 0.833 to 0.600, 0.978, 0.923, and 0.849, respectively. With 1.113 min-1 as threshold, the sensitivity and specificity values of Kep in predicting PLNM in patients with normal-sized lymph nodes were 0.909 and 0.667, respectively. CONCLUSIONS: Kep of primary tumor can be used as a surrogate marker to predict PLNM in cervical cancer.

Magnetic resonance neuroimaging promotes the preservation of pelvic autonomic nerves in laparoscopic total mesorectal excision: a comparative study.

BACKGROUND: How to preserve pelvic autonomic nerves system (PANS) in total mesorectal excision (TME) is still a technical challenge for gastrointestinal surgeons, and nerve preservation according to preoperative magnetic resonance imaging (MRI) is a hot topic in pelvic surgery. The purpose of this study was to assess the postoperative urogenital function of patients with rectal cancer (RC) who underwent preoperative and postoperative neuroimaging of PANS vs. patients who did not. METHODS: Patients meeting the inclusion criteria were prospectively enrolled in a magnetic resonance neuroimaging (MRN) group from June 2018, while primary RC patients from January 2016 to May 2018 who met the inclusion criteria were enrolled in a non-MRN group. Patients in the MRN group underwent MRN examination before operation and 6 months after operation, while those in the non-MRN group were collected and analyzed retrospectively. RESULTS: Based on International Prostate Symptom Score (IPSS) and International Index of Erectile Function 5 (IIEF5) scores at 6 months, the postoperative urinary and sexual function of male patients in the MRN group were significantly better than that in the non-MRN group (P<0.05). In addition, based on International Consultation on Incontinence modular Questionnaire on Female Lower Urinary Tract Symptoms (ICIQ-FLUTS) and Female Sexual Function Index (FSFI) scores at 6 months, the postoperative sexual function of female patients in the MRN group was significantly better than that in the non-MRN group (P<0.05). CONCLUSIONS: In the present study, we constructed a three-dimensional (3D) presentation of PANS based on preoperative MRN which showed in vivo pelvic autonomous innervation. This may promote the preservation of PANS during TME and reduce the postoperative urogenital dysfunction rate.

Intravoxel incoherent motion MRI in differentiation between recurrent carcinoma and postchemoradiation fibrosis of the skull base in patients with nasopharyngeal carcinoma.

PURPOSE: To determine the capacity of intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) in differential diagnosis between recurrent carcinoma and postchemoradiation fibrosis of skull base in patients with nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: Eleven patients with recurrent NPC and 21 patients with postchemoradiation fibrosis in the skull base were enrolled. All the diagnoses were proved by endoscopic biopsy or imaging follow-up. IVIM MRI was performed to obtain quantitative parameters including D (pure diffusion), f (perfusion fraction), and D* (pseudodiffusion). D, f, and D* were compared between two groups; the diagnostic performances of D and f were evaluated using the receiver operating characteristic (ROC) analysis. RESULTS: D and f values were significantly lower in recurrent carcinoma than that in fibrosis (P < 0.001; P = 0.001). No significant difference was found in D* values between recurrent carcinoma and fibrosis (P = 0.229). ROC curve analysis showed that the area under the curve of D and f values were 0.996 and 0.838, respectively. Respective cutoff values with sensitivity, specificity, and accuracy were: D = 1.161 × 10-3 mm2 /s (sensitivity 100.0%, specificity 95.2%, accuracy 96.9%), f = 0.109 (sensitivity 81.8%, specificity 71.4%, accuracy 75.0%). CONCLUSION: Recurrent NPC and postchemoradiation fibrosis in the skull base have distinctive D and f values. IVIM MRI could be used to differentiate between recurrent carcinoma and postchemoradiation fibrosis in patients with NPC. J. Magn. Reson. Imaging 2016;44:1556-1564.

MRI assessment of excess cardiac iron in thalassemia major: When to initiate?

BACKGROUND: To determine optimal initial age of cardiac iron screening with magnetic resonance imaging (MRI) T2* in patients with thalassemia major (TM). METHODS: We retrospectively reviewed black blood cardiac T2* assessments from 102 TM patients from the ages of 3 to 32 years. Cases of patients under and above 7 years old with detectable cardiac iron overload were analyzed separately. Associations between cardiac T2* and various factors, such as serum ferritin (SF), patient age and hepatic T2*, were assessed using either scatterplots or regression. Images were evaluated by two independent radiologists. RESULTS: With a T2* cut-off value of 20 ms, no patient under 5 years old showed cardiac iron overload. Three of 19 (15.8%) patients under 7 years of age had a cardiac T2* ≤ 20 ms (5.5 to 7 years) but none had ≤10 ms, while 35 of 83 (42.2%) patients above 7 years old had a cardiac T2* ≤ 20 ms (8 to 32 years) and 18 of them ≤10 ms. Cardiac T2* correlated weakly with serum ferritin and liver T2* (r = -0.39 and 0.41, respectively, both P < 0.001), but not with patient age (P > 0.05). CONCLUSION: Cardiac iron overload can occur in young TM patients, even as young as 5.5 years old. Assessment of cardiac iron with T2* might need to begin as early as 5 years old if suboptimal chelation therapy is administered.

Magnetic resonance imaging-visible and pH-sensitive polymeric micelles for tumor targeted drug delivery.

Folate-functionalized copolymers of poly(ethylene glycol) and 2-(diisopropylamino) ethylamine grafted poly(L-aspartic acid) are synthesized. The copolymers can self-assemble into nanoscaled micelles encapsulated with hydrophobic model drug Fluorescein Diacetate (FDA) and MRI diagnostic agents superparamagnetic iron oxide nanoparticles (SPIONs) in aqueous solution of a neutral pH resembling physiological environment, whereas disassemble in acidic endosomal/lysosomal compartments of tumor cells to achieve rapid drug release. In vitro drug release study showed that FDA release from the pH-sensitive micelles was much faster at pH 5.0 than at pH 7.4. Clustering of SPIONs inside the hydrophobic core of the micelles resulted in a high spin-spin (T2,) relaxivity for a super MRI sensitivity. Cell culture studies showed that the FDA-SPION-loaded micelles were effectively internalized by human hepatic Bel-7402 cancer cells following a folate receptor-mediated targeting mechanism, and then FDA was rapidly release from micelles inside lysosomal compartments. Micelles encapsulating paclitaxel (PTX) studies showed it can induce more effective cell toxicity. This study demonstrated the great potential of the pH-sensitive micelles as an effective multifunctional nanomedician platform for cancer therapy due to their active tumor targeting, pH-triggered drug release and ultrasensitive MRI responsiveness.

Magnetic resonance imaging of radiation-induced brain injury using targeted microparticles of iron oxide.

BACKGROUND: Radiation-induced brain injury (RBI) is the most serious complication of primary and metastatic brain and neck malignant tumors following radiation therapy. However, at present, RBI is difficult to diagnose in the early period. Recently, studies have demonstrated that the early stage of RBI is characterized by an inflammatory reaction, and that intercellular adhesion molecule-1 (ICAM-1) is significantly up-regulated in the irradiated brain tissues. PURPOSE: To provide an early diagnosis of RBI using molecular magnetic resonance imaging (MRI) with microparticles of iron oxide (MPIO) targeted to ICAM-1 in the vascular endothelium of brains. MATERIAL AND METHODS: A monoclonal antibody against ICAM-1 was conjugated to MPIO to form the targeted MRI contrast agent ICAM-MPIO. The adhesion of ICAM-MPIO to endothelial cells was quantified by optical imaging and MRI. Sprague-Dawley rats were irradiated to establish an animal model of the early period of RBI. ICAM-MPIO and free-MPIO were injected via tail vein, respectively. T(2) signal intensity and T(2) values of the irradiated brains and normal brains were subsequently evaluated by MRI. RESULTS: In vitro, the adhesion of ICAM-MPIO to the activated endothelial cells was 5 ± 0.5-fold greater than to the non-stimulated cells, which could be detected by optical imaging and MRI (R(2) = 1.0, P < 0.01). In vivo, ICAM-MPIO caused a marked negative MRI contrast effect in irradiated brains. As compared with brains without irradiation, the specific contrast effect increased more than seven-fold after administration of ICAM-MPIO (F = 751.495, P < 0.05). CONCLUSION: MPIO coated with monoclonal antibody of ICAM-1 could be used for detecting the early period of RBI by optical imaging and MRI.

[Adenovirus mediated gene transfer of tyrosinase gene on HepG2 cell by magnetic resonance imaging].

OBJECTIVE: To evaluate the transfect results of recombinant adenovirus vector carrying tyrosinase gene (Ad-tyr) in vitro by magnetic resonance imaging (MRI) after the Ad-tyr was transfected into HepG2 cell. METHODS: The Ad-tyr which carried the full-length cDNA of tyrosinase gene was transfected into HepG2 cell. The transfected cells were scan by MRI sequences of T1 weighted image (T1WI) , T2 weighted image (T2WI) , and short time inversion recovery (STIR) to observe the MRI signals of expressed melanin. Masson-Fontana staining was performed to search for melanin granules in transfected cells. Real-time PCR method was used to search for cDNA of tyrosinase gene. RESULTS: Ad-tyr was transfected into HepG2 cells and synthesized a large amount of melanin inside. The synthesized melanin of 1 x 10(6) cells which had been transfected by Ad-tyr with the 50, 150, and 300 multiplicity of infection separately were all sufficient to be detected by MRI and showed high signals in MRI T1WI, T2WI, and STIR sequences. The signal intensities of MRI were positively correlated to the amounts of transfected Ad-tyr. The melanin granules were found in HepG2 cells in Masson-Fontana staining. The cDNA amount of tyrosinase gene in transfected HepG2 cells, which was detected by real-time PCR, was remarkably higher than that in nontransfected cells. CONCLUSION: The synthesized melanin of HepG2 cells, which controlled by expression of exogenous gene, can be detected by MRI, indicating that the adenovirus vector can efficiently carry the tyrosinase gene into HepG2 cells.

[Diffusion weighted imaging features of normal uterine cervix and cervical carcinoma].

BACKGROUND & OBJECTIVE: Magnetic resonance imaging (MRI) is a feasible method to detect, diagnose and stage cervical cancer. This study was to analyze the diffusion weighted imaging (DWI) features of normal uterine cervix and cervical carcinoma, and assess the values of DWI in diagnosis and monitor of cervical carcinoma after radiotherapy. METHODS: Routine MRI sequence and axial diffusion weighted sequence (b=800 s/mm2) were performed in 20 patients with cervical carcinoma and in 16 healthy women as control. The apparent diffusion coefficient (ADC) values of normal uterine cervix and cervical carcinoma were compared. The ADC values of 7 cervical carcinoma patients before and after radiotherapy were compared. RESULTS: Normal uterine cervix presented 3 layers in DWI. The ADC value was significantly higher in normal uterine cervix than in cervical carcinoma [(1.71+/-0.14) x 10-3 mm2/s vs. (0.97+/-0.13) x 10(-3) mm2/s, P<0.01]. The ADC value of cervical carcinoma after radiotherapy was higher than that before radiotherapy [(1.49+/-1.40) x 10(-3) mm2/s vs. (1.02+/-0.06) x 10(-3) mm2/s], but was still lower than that of normal uterine cervix. CONCLUSION: DWI could be used to distinguish cervical carcinoma from normal uterine cervix, evaluate the extension of cervical carcinoma before therapy, and monitor the treatment response of cervical carcinoma after radiotherapy.

[Clinical significance of diffusion-weighted MRI with STIR-EPI in differential diagnosis of cervical lymph nodes].

OBJECTIVE: To evaluate the feasibility and efficacy of a new MRI imaging method--diffusion weighted imaging (DWI) with short TI version recovery-echo planar imaging (STIR-EPI) sequence in differentiating benign cervical lymph nodes from malignant ones. METHODS Twenty nasopharyngeal carcinoma patients and fourteen volunteers received both conventional MRI and DWI with STIR-EPI. Ability of detecting lymph nodes between conventional MRI and STIR-EPI-DWI was compared, and the difference of apparent diffusion coefficient (ADC) value between metastatic lymph node and normal lymph node was analyzed. RESULTS: DWI was more sensitive in detecting lymph node than conventional MRI. ADC value of metastatic lymph node (0. 766 +/- 0. 119) x 10 (-3) mm(2)/s was significantly lower than that of normal lymph node (0. 975 +/- 0. 179) x 10 - mm2/s (P < 0. 01). CONCLUSION: As a new MRI imaging technique in detecting cervical lymph nodes, diffusion weighted imaging ( DWI) with short TI version recovery-echo planar imaging ( STIR-EPI) sequence is more reliable and sensitive than conventional MRI imaging, providing an alternative way to differentiate benign lymph nodes from malignant ones.

[MRI performance and diagnosis of schwannomas from cranial nerves in posterior cranial fossae].

BACKGROUND & OBJECTIVE: Cranial nerve schwannomas originate frequently in posterior cranial fossae and have various and complex MRI performances, some of which are still not well known. This study was to explore MRI performances and features of schwannomas from cranial nerves in posterior cranial fossae. METHODS: The MRI performances of 75 cases of schwannoma from cranial nerves in posterior cranial fossae, including trigeminal (n=9), facial (n=1), acoustic (n=53), 9th-11th (n=9) and hypoglossal (n=3) schwannomas, confirmed by surgical and pathologic findings, were analyzed retrospectively. RESULTS: Most of schwannomas in posterior cranial fossae were solid-cystic lesions when their sizes were larger than 1.5 cm in diameter. Small lesions (less than 1.5 cm in diameter) may be completely solid, which were closely related to cranial nerves. On T1WI, the solid part of tumor appeared iso- or slightly hypointense, while cystic part was hypointense. On T2WI, solid part appeared high or slightly high signal intensity, but cystic part appeared very high signal intensity. On contrast-enhanced T1WI, there was obvious enhancement in the solid part, but not in the cystic part. Some typical signs were very useful to infer tumor origin, such as, dumbbell-shaped trigeminal schwannoma extended across the middle and posterior cranial fossa, enlargement of internal auditory canal, widened jugular foramen and hypoglossal foramen caused by acoustic schwannoma, the 9th-11th shcwannoma, and hypoglossal schwannoma, respectively. The correct ratio for qualitative diagnosis of schwannoma was 92% using MRI, but the incorrect ratio for identifying the nerve of tumor origin was 8.7%. CONCLUSION: MRI is a good method in qualitative diagnosis of schwannoma and identifying cranial nerves of tumor origin in posterior cranial fossae.

[Three-dimensional reconstruction and image fusion between liver focal lesions and dynamic contrast-enhanced magnetic resonance angiography].

BACKGROUND & OBJECTIVES: Identifying the correlation of focal lesions to the liver vessel system is a key factor in selecting treatment patterns for focal hepatic diseases. This study was to evaluate the feasibility of 3-dimensional reconstruction and the fusion image between the 3-dimensional dynamic contrast-enhanced magnetic resonance angiography (3D DCE MRA) and the focal hepatic lesions, and further, explore the clinical application of this method. METHODS: 3D DCE-MRA and conventional magnetic resonance imaging (MRI) were performed. The angiography and focal hepatic lesions were reconstructed with maximum intensity projection (MIP) and surface shaded display (SSD), and then fused together. Of the 25 cases with evaluable images, 2 were hemangioma, 3 were focal nodular hyperplasia, 1 was hepatocellular adenoma, 2 were macroregenerative nodule, 2 were hepatobiliary cystadenocarcinoma, and 17 were hepatocellular carcinoma; 21 were confirmed by operation resection, and 4 received digital subtraction angiography (DSA). RESULTS: The anatomic relationship between the lesions and the vessels were well shown. Of the 27 cases, 5 showed normal vessel branching, 6 showed feeding arteries from the hepatic artery, 11 showed compressed and shifted trunks of the vessels, 6 showed tumor invaded vessels, and 11 showed the tumor embolism in the portal vein or the inferior vena cave; 9 also showed MRI signs of portal hypertension. MIP was prior to SSD in demonstrating small branches of the hepatic vessels. CONCLUSION: The 3-dimensional reconstruction and fusion images between 3D DCE-MRA and the focal hepatic lesions by using MIP and SSD can easily display the anatomic relationship between the focal hepatic lesions and the hepatic vessels, and thus can help the surgeons to localize lesions, minimize operating time and decide the extent of surgical resection.

[Preliminary application of functional magnetic resonance imaging to neurosurgery].

BACKGROUND & OBJECTIVE: Motor functional deficit may be caused by surgery resection of brain tumors around the central sulcus. This study was to evaluate the application of functional magnetic resonance imaging (fMRI) to neurosurgery through identifying motor hand functional cortex and depicting the relationship between the cortex and tumor with fMRI before surgery. METHODS: Routine MRI and fMRI were performed on 31 patients with brain tumor around the central sulcus. Of the 31 cases of brain tumor, 10 were metastases, 11 were gliomas, 6 were meningiomas, 2 were arterial-venal malformation (AVM), and 2 were arachnoid cysts. fMRI was performed using FFE-EPI sequence. Sixteen continuent slices with 4 mm thickness and 0 gap parallel to bicommissural line were scanned during the rest, and actions of opening and closing of hand were imaged. A total of 1,280 functional original pictures and statistical Z-score maps were obtained. RESULTS: The activation areas of motor hand functional cortex were showed in all patients except 2 whose heads moved obviously during the scanning. The minimal distance between the functional cortex and tumor was measured. There were 3 types of activation of motor hand functimal cortex, including activation spots in or near the tumor, deformation and shift of cortex activation area, normal shape and location of cortex activation area. Other activation areas in different places of brain in individual patients were also appeared. CONCLUSION: fMRI may help to identify the relationship between the brain tumors near central sulcus and the location of motor hand functional cortex, therefore, provide reference for neurosurgery.

[Types of liver metastases on MR imaging and characteristics of uncommon types].

BACKGROUND & OBJECTIVE: Although liver metastases are very common, some of them would be misdiagnosed because of their specific appearance on imaging. This study was to summarize the types of liver metastases according to the magnetic resonance imaging (MRI) appearance, and explore the characteristics of uncommon types to improve the accuracy of diagnosis. METHODS: A total of 174 consecutive patients with liver metastases were screened from the patients with diagnosis or suspicion of liver metastases according to plate or enhanced MRI scan. Liver metastases were confirmed through pathologic examination, medical imaging, or follow-up. Lesions were categorized as nodular, segment, and diffusion classes by shape, and categorized as common, mimicking hemangioma, and mimicking cyst patterns according to the characteristics of signal intensity. RESULTS: Common primary tumors of liver metastases were colon and rectum carcinomas (31.0%). According to the shape of lesions, the proportions of nodular, segment, and diffusion classes were 96.6%, 2.3%, and 1.1%, respectively. According to the characteristics of signal intensity, the proportions of common, mimicking hemangioma, and mimicking cyst patterns were 87.9%, 4.0%, and 8.1%, respectively. CONCLUSIONS: Most liver metastases are nodular in shape, and present as common pattern, but some uncommon types also exist. MRI scan and clinical follow-up could increase the accuracy of diagnosis.

[Significance of dynamic enhanced MRI in differential diagnosis of radiofibrosis and recurrent nasopharyngeal carcinoma at the basilar clivus].

BACKGROUND & OBJECTIVE: Basilar clivus is a common site of recurrent nasopharyngeal carcinoma (RNPC). Biopsy of the basilar clivus is seldom done because of its deep location and complex anatomic structure, therefore, early differential diagnosis of radiofibrosis (RF) and RNPC at the basilar clivus is very difficult. This study was designed to investigate the characteristics of radiofibrosis and RNPC at the basilar clivus on dynamic enhanced magnetic resonance imaging (DMRI) for differential diagnosis. METHODS: A total of 38 NPC patients, treated in Cancer Center and the Second Affiliated Hospital of Sun Yat-sen University with follow-up of 1-5 years, were divided into 2 groups: 22 in RF group and 16 in RNPC (RNPC at the basilar clivus) group. After conventional plain MRI scan of nasopharynx, DMRI and conventional contrast enhanced T(1)-weighted imaging (T1WI) were performed. Maximal contrast enhancement ratio (MCER), time to MCER (Tmax), and contrast enhancement ratio at the 40th second of DMRI (CER(40s)) of basilar clivus, condylar process, and nasal concha were measured. RESULTS: The MCER and CER(40s) of RF at the basilar clivus were lower, and the Tmax was longer than those of RNPC at the basilar clivus. When CER40s > or =150%, CER40s of basilar clivus > or = CER(40s) of nasal concha, and the combination of these 2 indexes were respectively set as the DMRI diagnostic criteria of RNPC at the basilar clivus, the diagnostic sensitivity of the second criterion was the highest (81.3%), and the diagnostic specificity of the third criterion was also the highest (86.4%). CONCLUSIONS: DMRI is helpful for differential diagnosis of radiofibrosis and RNPC at the basilar clivus. RNPC at the basilar clivus is highly suggested when it meet the criteria of both CER(40s) > or =150% and CER(40s) of basilar clivus > or = CER(40s) of nasal concha. When the 2 criteria are conflictive, the latter is more accurate, MCER and Tmax of the basilar clivus should be took into consideration.

[Correlation of MR imaging features and histopathology of synovial sarcoma].

BACKGROUND & OBJECTIVE: Magnetic resonance imaging (MRI) is the best detective technique for soft tissue tumors, but it lacks specific imaging signs to distinguish various tumors. The synovial sarcoma is observed more frequently in soft tissue tumors. This study was to evaluate correlation of MRI features and histopathology of synovial sarcoma, and to improve the diagnostic accuracy of synovial sarcoma by MRI. METHODS: Twelve patients with synovial sarcomas were confirmed by operation and histopathology, included 9 men, and 3 women, aged from 35 to 50 years. Ten tumors located in lower limbs, 2 located in upper limbs. MRI was performed with a 0.5T magnet system. All images were obtained through T1-weighted imaging (T(1)WI), and T(2)-weighted imaging (T(2)WI), and some images were obtained by T(2)WI with stair. All patients received enhanced scan after Gd-DTPA injection. Radiological and histopathologic findings were compared. RESULTS: All tumors located in the places closed to joints, 2 invaded into joints, 3 invaded into bones. On T(1)WI, 12 tumors displayed signal intensity similar to that of skeletal muscle, and 3 showed cystic high intensity areas similar to that of subcutaneous fat. On T(2)WI, 6 tumors showed hyper-, iso-, and hypointense areas relative to fat constituting a triple signal intensity; 6 were multilocular, 3 were irregular, 3 were circular or elliptical. The septa configurations were seen in 5 tumors, fluid-fluid level sign was seen in 1 tumor. Maximum diameters of tumors ranged from 3 to 13 cm. All tumors enhanced asymmetrically after Gd-DTPA injection. On histological examination, 7 were poorly differentiated monophasic type, 3 were well differentiated monophasic type, 2 were biphasic type, 6 had old and/or fresh hemorrhage, 5 had large necrosis areas, 2 had calcification. CONCLUSION: MRI manifestation is specific in synovial sarcoma, and may be correlated with histopathology of synovial sarcoma.

[MRI performance and diagnosis of meningioma--a report of 126 cases].

BACKGROUND & OBJECTIVE: In MRI study of meningioma, it was lack of large group of patients to evaluate MRI qualitative diagnosis, and no consensus had been achieved concerning problems such as peritumoral edema in meningioma. This study was to summarize main clues for diagnosing meningioma through analyzing MRI performance of 126 patients with meningioma. METHODS: Among 126 patients with meningioma, 32 were syncytial, 35 were fibroblastic, 24 were psammomatous, 9 were angioblastic, 18 were transitional, 3 were papillary, and 5 were malignant. All patients were scanned with T1, T2-weighted imaging (T1WI, T2WI), and contrast-enhanced T1WI. RESULTS: Convexity of brain was more likely to be involved, among 126 cases of meningioma, 45 (35.7%) tumors located at convexity of brain. The size of tumor ranged from 1.4 to 9.9 cm. Eighty-one percent of tumors were round or oval in shape. Isointensity or slight hyperintensity of T2WI signals detected in 70.6% patients. The rates of tail sign, and pseudo-capsule were 62.7%, and 49.2%. Extruding sign of brain parenchyma was observed in 83.8% (57/68)of patients with tumor size of > 4 cm. Significantly even and increasing sign in contrast-enhanced T1WI were observed in 104 patients (82.5%). Peritumoral edema occurred in 57 patients (45.1%), and related to tumor size. Other rare signs included cystic changes, bleeding, calcification, osteal changes, and introtumoral vessel symptoms. The correct rate of diagnosis was 95.2%. CONCLUSIONS: MRI performances of meningioma are various. Judgment of extra-brain tumor, typical T2WI signals, tail sign, and significantly even and increasing sign are key factors for diagnosing meningioma.

[Diagnostic value of MR diffusion tensor imaging on radiation-induced early brain injury of nasopharyngeal carcinoma after radiotherapy].

BACKGROUND & OBJECTIVE: MR diffusion tensor imaging (DTI), a new MRI technique, can observe water molecule diffusion non-invasively at molecular level. This study was to assess diagnostic value of DTI on post-radiotherapy brain injury by quantitatively analyzing diffuse features of water in bilateral temporal lobes alba of those nasopharyngeal carcinoma (NPC) patients with normal conventional MRI performances. METHODS: DTI was performed in 13 NPC patients with normal conventional MRI performances after radiotherapy, and 21 healthy controls. Isotropic apparent diffusion coefficient (ADCiso) and anisotropic index (AI) were measured in bilateral temporal lobes alba. RESULTS: ADCiso of patient group was (631.30+/-27.83) x 10(-6) mm2/s, while that of control group was (651.76+/-39.10) x 10(-6) mm2/s (P>0.05). Temporal lobes diffusion AI decreased significantly in patient group, mean fractional anisotropy (FA) was 0.405+/-0.042, mean relative anisotropy (RA) was 0.355+/-0.044, and mean 1 minus volume ratio (1-VR) was 0.192+/-0.042; while those in control group were 0.463+/-0.047, 0.418+/-0.052, and 0.257+/-0.055, respectively (P< 0.01). CONCLUSIONS: DTI can early detect subtle alba changes in NPC patients after radiotherapy, which conventional MRI failed to sense. AI is more sensitive than ADCiso, may better describe the diffuse features of water molecules, and evaluate the temporal lobes alba changes before and after NPC radiotherapy.