Mechanical thrombectomy in low Alberta Stroke Program Early Computed Tomographic Score: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Due to their poor natural history and lack in level-I evidence, patients with large vessel occlusion and large core infarcts (Alberta Stroke Program Early Computed Tomographic Score <6) have been excluded from receiving mechanical thrombectomy. This systematic review and meta-analysis seeks to summarize current evidence from published randomized controlled trials to compare the safety and efficacy of mechanical thrombectomy with optimal medical therapy in treating stroke patients with large core infarcts. METHODS: We searched PubMed and EMBASE for randomized controlled trials investigating the safety and efficacy of mechanical thrombectomy vs optimal medical therapy in patients presenting with large vessel occlusion and large infarcts. Basic demographic and comorbidities were assessed, and clinical outcomes were compared, including modified Rankin scale 0-3, and 0-2 at 3 months, symptomatic intracranial hemorrhage, decompressive hemicortectomy, and 90-day mortality. RESULTS: Three randomized controlled trials totaling 1011 patients (501 and 510 in the medical management and mechanical thrombectomy arm, respectively) were included. Patients undergoing mechanical thrombectomy had significantly higher odds of achieving better functional outcomes at 3 months: Modified Rankin scale 0-2 (OR = 3.05, 95% CI = 2.101-4.4021, p < 0.0001) and modified Rankin scale 0-3 (OR = 2.20, 95% CI = 1.67-2.89, p < 0.0001) as compared to those receiving optimal medical management. There were no differences between groups in 90-day mortality (OR = 0.93, 95% CI = 0.70-1.23, p = 0.60), symptomatic intracranial hemorrhage (OR = 1.89, 95% = CI 0.95-3.77, p = 0.07) or decompressive hemicraniectomy (OR = 1.25, 95% CI = 0.69-2.25, p = 0.46). CONCLUSION: Mechanical thrombectomy for patients with large infarcts is associated with improved functional outcomes and a similar safety profile compared to optimal medical management. Ongoing trials will help better refine the target population that benefits the most from treatment.

Efficacy of 3D VIBE Dixon fat quantification for differentiating clear-cell from non-clear-cell renal cell carcinoma.

AIM: To assess the efficacy of three-dimensional (3D) volumetric interpolated breath-hold examination (VIBE) magnetic resonance imaging (MRI) with Dixon quantification for differentiating clear-cell from non-clear-cell types of renal cell carcinoma (RCC). MATERIALS AND METHODS: The 3D VIBE Dixon renal MRI examinations of 44 patients with 45 histologically confirmed RCCs was analysed. The fat fractions and signal intensity indexes (SIindex) of the solid portions of clear-cell and non-clear-cell RCCs were measured and compared using Student's t-test and receiver operating characteristic (ROC) curves. The agreement of measurements among observers was evaluated by the intraclass correlation coefficient (ICC), and Bland-Altman plots. RESULTS: The mean values of fat fraction (13.16±7.16%) and SIindex (22.64±15.7%) in clear-cell RCCs were significantly higher than that in non-clear-cell RCCs (7.7±2% and 7.9±4.8%; p<0.001, respectively). With the area under the ROC curve (AUC) of the fat fraction at 0.811, 75% (95% CI: 55.1-89.43%) sensitivity and 76.5% (95% CI: 50.1-93.2%) specificity for diagnosing clear-cell RCC were obtained at a cut-off fat fraction value of 8.9%. With a cut-off value of 8.89%, the diagnostic sensitivity and specificity were 85.7% (95% CI: 67.3-96%) and 70.6% (95% CI: 44-89.7%), respectively. The AUC of the SIindex was 0.870 (0.766-0.973). ICC and Bland-Altman plots show excellent agreement of the tumour fat fraction and SIindex measurement between the two observers. CONCLUSION: Intracellular lipid content analysis using the 3D Dixon technique can help to differentiate clear-cell from non-clear-cell RCCs.

Preliminary study of diffusion-weighted MRI in the preoperative diagnosis of cystitis glandularis.

AIM: To assess the efficacy of diffusion-weighted (DWI) magnetic resonance imaging (MRI) in distinguishing cystitis glandularis (CG) from bladder urothelial carcinoma. MATERIALS AND METHODS: Ultrasound, computed tomography (CT), conventional MRI, and DWI of 30 patients with histopathologically confirmed CG were analysed retrospectively and the imaging findings were correlated to the findings at histology. RESULTS: Ultrasound was non diagnostic in 11/18 and misdiagnosed malignancy in 7/18; CT was non diagnostic in 6/10 and misdiagnosed malignancy in 4/10; MRI was non diagnostic in 0 and misdiagnosed malignancy in 4/5 respectively. One patient with diffuse bladder wall thickening was correctly diagnosed as CG at MRI. All six patients who underwent additional DWI were accurately diagnosed as having CG with no or minimal reduction of diffusion. CONCLUSIONS: Diffusion is not reduced or shows minimal reduction in CG. DWI may aid the differential diagnosis of CG.

Value of normalized apparent diffusion coefficient for estimating histological grade of vesical urothelial carcinoma.

AIM: To compare the efficacy of apparent diffusion coefficient (ADC) and normalized ADC (nADC) for estimating the histological grade of vesical urothelial carcinoma and to identify an optimal reference for nADC calculation. MATERIALS AND METHODS: Thirty patients with histologically confirmed vesical urothelial carcinomas underwent preoperative diffusion-weighted magnetic resonance imaging (DW-MRI) of the pelvis. nADC of the tumour was calculated as ADC (tumour)/ADC (reference) using urine in the bladder lumen, and the obturator internus and gluteus maximus muscles as reference. Receiver operating characteristic (ROC) curves were constructed and compared to identify an optimal reference for nADC calculation. RESULTS: Both ADC and nADC of low-grade tumours (1.112 ± 0.159 × 10(-3) mm(2)/s, 0.403 ± 0.047 × 10(-3) mm(2)/s) were significantly (p < 0.001) higher than those of high-grade tumours (0.772 ± 0.091 × 10(-3) mm(2)/s, 0.276 ± 0.033 × 10(-3) mm(2)/s). The area under the nADC ROC curve using urine as reference was significantly (p = 0.000) larger (0.995) than those using obturator internus (0.960) and gluteus maximus (0.945). CONCLUSIONS: nADC is superior to ADC for estimating the histological grade of bladder carcinoma using urine in the bladder lumen as an optimal reference for nADC calculation.

Over-expressions of AMPK subunits in ovarian carcinomas with significant clinical implications.

BACKGROUND: AMP-activated protein kinase (AMPK) has recently been considered as a potential target for cancer therapy. However, the expression status of various subunits of the heterotrimeric AMPK in human cancers is rarely reported. We decided to determine their expressions in ovarian carcinomas and their relationships with the disease. METHODS: Expressions and locations of the AMPK-α1, -α2, -ß1, -ß2, -γ1 and -γ2 were detected by quantitative PCR (Q-PCR) and immunohistochemical staining (IHC). Their expression levels in ovarian tumors were compared with normal controls and also correlated with clinicopathological parameters. RESULTS: Except AMPK-α1, expressions of the other five AMPK subunits are significantly higher in ovarian carcinomas as determined by Q-PCR. Although IHC detection of AMPK-γ1 and -γ2 were not successful, over-expressions of AMPK-α2, -ß1, and -ß2 were further confirmed by IHC. Over-expressions of various AMPK subunits occurred independently and were mainly detected in the cytoplasm. Interestingly, AMPK-α2 and -ß1 were also detected in the nucleus and cell membrane, respectively. Clinical correlation analyses indicate that expressions of different AMPK subunits are associated with different subtypes of carcinoma. High expression of AMPK-α2 is significantly associated with endometrioid carcinomas. On the other hand, high expressions of AMPK-ß and -γ subunits are associated with mucinous and serous carcinomas, respectively. Furthermore, high expressions of AMPK-ß1 and -γ2 are also associated with early and late stages of disease, respectively. Finally, patients with high expression of AMPK-α2 had better prognosis. CONCLUSIONS: Aberrant expressions of AMPK subunits may play important roles in ovarian carcinogenesis. Each AMPK subunit may have its own function other than just a component of the AMPK molecule. Correlations with clinical parameters suggest that expressions of AMPK subunits have different clinical implications in ovarian cancer development.

Tuberculosis of the parotid gland: computed tomographic findings.

BACKGROUND: Tuberculosis (TB) of the parotid gland is rare, even in endemic regions. Approximately 100 cases have been reported in the English literature. The computed tomographic (CT) features, however, have seldom been studied. PURPOSE: To determine the diagnostic CT features of tuberculosis of the parotid gland. MATERIAL AND METHODS: CT studies of four histologically proven cases of tuberculosis of the parotid gland were retrospectively reviewed. RESULTS: A total of 15 enlarged lymph nodes were found in the superficial lobes of the parotid glands. The nodes were arranged linearly within the gland. Enhancement patterns included homogeneous enhancement (9/15, 60%), homogeneous enhancement with eccentric microcysts (3/15, 20%), and thick-walled rim enhancement with central lucency (3/15, 20%). Thickened adjacent fascial plane and platysma were seen in two patients. Ipsilateral cervical lymphadenopathy was seen in all patients. CONCLUSION: In patients presenting with unilateral parotid nodules, TB should be considered when linearly arranged enhancing nodules are demonstrated in the superficial lobes of the glands on CT scan.

Magnetic resonance imaging of pregnancy in suspected uterine anomaly.

Uterine malformation is associated with higher rate of obstetrical complication. Ultrasound cannot reliably delineate the uterine abnormality, especially in obese women. These two case reports illustrate the value of MRI in depicting the uterine and fetal anatomy, thus assisting the appropriate management of these patients.

Accuracy and test-retest precision of quantitative cartilage morphology on a 1.0 T peripheral magnetic resonance imaging system.

OBJECTIVE: Quantitative magnetic resonance imaging (qMRI) of knee cartilage morphology is a powerful research tool but relies on expensive and often inaccessible 1.5 T whole-body equipment. Here we examine the reproducibility and accuracy of qMRI at 1.0 T by direct comparison with previously validated technology. METHODS: Coronal images of the knee were obtained in six healthy and six osteoarthritic participants. Two data sets were acquired with a 1.5T whole-body magnetic resonance imaging (MRI) system and two with a 1.0 T peripheral MRI system, with repositioning between scans. Proprietary software was used to analyze surface area, volume, and thickness of femoral and tibial cartilage. RESULTS: At 1.0 T, precision errors for surface areas (root-mean-square (RMS) coefficient of variation (CV%)=1.7-2.6%) were higher than those at 1.5 T (1.0-2.1%). For volume and thickness, precision errors were 2.9-5.5% at 1.0 T compared to 1.6-3.4% at 1.5 T. High levels of agreement were found between the two scanners over all plates. With the exception of lateral femoral cartilage (volume and thickness), no statistically significant systematic bias was found between 1.0 T and 1.5 T. CONCLUSIONS: This is the first reported study to show that knee cartilage morphology can be determined with a reasonable degree of accuracy and precision using a 1.0 T peripheral scanner. Peripheral MRI is less costly, can be performed in clinical offices, and is associated with higher patient comfort and tolerance than 1.5 T whole-body MRI. Implementation of qMRI with peripheral systems may thus permit its more widespread use in clinical research and patient care.

Imaging of vascular disorders of the female pelvis.

Clinical presentation of vascular disorders of female pelvis including placental adhesion, retained product of conception, ovarian venous thrombosis, varices, torsion and haemorrhagic infarct of ovary is often non-specific. Because of its availability, safety, and cost-effectiveness, ultrasound is the first investigation of choice. Computed tomography and MRI clearly depict the pelvic and retroperitoneal anatomy. This pictorial essay illustrates the complementary role of US, CT, and MRI in diagnosing vascular disorders of female pelvis.

Continuing professional education and the Internet: views of Alberta occupational therapists.

BACKGROUND: Occupational therapists have identified barriers to accessing continuing professional education (CPE) in the traditional face-to-face formats. One alternative to traditional, centrally located, face-to-face CPE is course delivery through the Internet. PURPOSE: This study examined Alberta occupational therapists' perceptions of Internet-based CPE. METHOD: A questionnaire was mailed to 800 randomly sampled Alberta occupational therapists (response rate = 35.5%; n = 281). RESULTS: Respondents pursued CPE to increase skills, knowledge and maintain clinical competency. They reported that a face-to-face CPE course was more useful than distance courses. Although almost 90% of respondents had access to computers with an Internet connection at home or at work, and nearly 65% thought that their computer knowledge was sufficient, only 2.9% had previously taken Internet-based CPE. PRACTICE IMPLICATIONS: In order for the Internet to be accepted as a common, useful and alternative delivery tool for CPE in occupational therapy, the perceived barriers such as the lack of personal time, cost, and limited interaction with other learners and instructors will need to be addressed.

The relationships between bone mineral density in the spine, hip, distal femur and proximal tibia and medial minimum joint space width in the knees of healthy females.

OBJECTIVE: To investigate the relationships between bone mineral density (BMD) in the hip, spine, distal femur and proximal tibia and minimum joint space width (mJSW) in the knees of healthy women. METHODS: Women 22-68 years old without a history of knee pain, bone or joint disease or injury underwent a single, fixed-flexion knee X-ray. Radiographs were graded according to the Kellgren-Lawrence scale and analyzed for mJSW using a computer algorithm. Dual X-ray absorptiometry scans of the spine, hip, distal femur and proximal tibia were also acquired for each participant. Femur and tibia scans were acquired and analyzed using a modified version of the lumbar spine software. RESULTS: Forty-five females, mean [standard deviation (SD)] age and body mass index (BMI) of 40.1 (13.9) years and 24.6 (4.5)kg/m(2), respectively, participated. The mean (SD) mJSW was 4.64 (0.68)mm. Linear regression analyses controlling for age and BMI revealed that BMD in the femoral trochanter and the central two regions of the tibia (T2 and T3) was significantly related to mJSW in the knee. A backwards regression analysis performed to determine which region of interest is most significantly related to mJSW revealed that femoral trochanter BMD (beta-value=0.416) is the most significant. CONCLUSIONS: In contrast to the suggestion that BMD is negatively correlated with mJSW in the knees of osteoarthritic individuals, these results suggest that increasing BMD in the femoral trochanter and tibia is significantly associated with increasing mJSW in healthy females. Further investigation of this relationship is warranted.

Abnormalities identified in the knees of asymptomatic volunteers using peripheral magnetic resonance imaging.

OBJECTIVE: To estimate the prevalence of bone and soft tissue abnormalities in asymptomatic knees using peripheral magnetic resonance imaging (pMRI) and to examine the relationship between these abnormalities and Kellgren-Lawrence (K-L) graded X-rays. METHOD: Volunteers (20-68 years) with no history of knee pain, injury or bone or joint disease were recruited. Individuals underwent a single MRI scan and radiograph of their non-dominant knee. pMR images were acquired in sagittal plane using a 3-D gradient-echo protocol. Two radiologists graded the presence and severity of cartilage degeneration, osteophytosis, meniscal and ligamentous abnormalities, bone marrow edema and subchondral cysts. X-rays were acquired using a fixed-flexion technique and graded using the K-L scale. RESULTS: Forty-four individuals, mean age (SD) 41.1 (14.2) years, participated. K-L grading of X-rays revealed 29 individuals were grade 0, 12 were grade 1 and 3 were grade 2. Five individuals showed evidence of cartilage lesions, the femoral trochlea, medial femur and patella being those regions most commonly affected. Twelve individuals (27.3%) showed evidence of osteophytosis, nine of whom did not show evidence on X-ray. Forty-three individuals showed evidence of at least one meniscal abnormality while 27 individuals (61.4%) had abnormalities in at least three of the four regions of the knee. CONCLUSION: Our results suggest that osteophytes may be more prevalent in this population than radiographic data suggests due to the limitations of two-dimensional imaging. Meniscal degeneration or tears, a risk factor for knee osteoarthritis, are highly prevalent in asymptomatic individuals with the medial anterior and posterior horns being the most commonly affected regions.

Magnetization transfer imaging diagnosis of intracranial tuberculomas.

Tuberculomas (TB) can mimic brain tumors and abscesses. We performed prospective magnetization transfer ratio (MTR) analysis on 60 patients with 52 intracranial TB, 13 pyogenic abscesses and 65 tumors to determine the efficacy of magnetization transfer (MT) imaging in the differential diagnosis of brain tumors and infection. The nonenhancing cores of TB had significantly higher (P=.026) MTR (0.14+/-0.29) than necrotic components of high-grade gliomas (-0.19+/-0.22). The MTR of cores of TB were also higher than those of the cystic areas of low-grade gliomas (-0.53+/-0.32), benign (-0.09+/-0.21) and malignant (-0.07+/-0.25) tumors, and abscesses (-0.03+/-0.13), but the differences were not significant because of the small number of tumors and abscesses. There was also no significant difference between the MTR of abscesses, malignant and benign tumors. Using the criteria of MTR of necrotic center > 0.14 (mean MTR of TB) for diagnosing TB, MTR <-0.03 (mean MTR of abscesses) for diagnosing tumors and MTR between these values for diagnosing abscesses, MTI had diagnostic sensitivity of 68.42%, specificity of 80.49%, and accuracy of 76.67%. The improved diagnostic accuracy of MRI with the addition of MTR analysis from 86.67% to 91.67% and from 85.71% to 87.50% for both radiologists respectively was not significant. MTR analysis helped us to differentiate solitary TB or abscess from low-grade glioma in five patients and to diagnose multiple TB, abscesses, and metastases in four.

Magnetic resonance imaging findings in tuberculous meningoencephalitis.

OBJECTIVE: To evaluate the efficacy of magnetic resonance imaging (MRI) for distinguishing tuberculosis from other types of meningoencephalitis. PATIENTS AND METHODS: MRIs of 100 patients with tuberculous (50), pyogenic (33), viral (14), or fungal (3) meningoencephalitis were analyzed independently by 2 radiologists. Number, size, location, signal characteristics, surrounding edema, and contrast enhancement pattern of nodular lesions; location and pattern of meningeal enhancement; extent of infarct or encephalitis and hydrocephalus were evaluated. RESULTS: Contrast-enhancing nodular lesions were detected in patients with tuberculous (43 of 50 patients), pyogenic (9 of 33), and fungal (3 of 3) infections. No nodules were detected in patients with viral meningoencephalitis. Using the criteria of 1 or more solid rim or homogeneously enhancing nodules smaller than 2 cm, the sensitivity, specificity and accuracy for diagnosing tuberculous meningitis were 86.0%, 90.0% and 88.0%, respectively. CONCLUSION: Magnetic resonance imaging is useful in distinguishing tuberculous from pyogenic, viral and fungal meningoencephalitis.

Magnetization transfer analysis of brain tumor, infection, and infarction.

Magnetization transfer (MT) imaging has been used to characterize tissues. A prospective analysis of magnetization transfer ratio (MTR) was performed on 107 patients with brain tumors, infection, and infarction to determine its efficacy in differential diagnosis. MTRs of brain tumor, infection, and infarction were significantly lower than those of normal gray and white matter. The cystic centers of infection had significantly higher MTRs than infarct and cystic tumors. The MTRs of infarction were significantly higher than those of cystic low-grade gliomas and benign tumors. The non-enhancing cystic components of infection, low-grade gliomas, and benign tumors were readily distinguished from solid infarction on enhanced images without MT. Using the MTR of 0.01 as a cutoff, the sensitivity, specificity, and accuracy of MT imaging for distinguishing cystic infection from cystic tumors were 90.00%, 75.86%, and 79.49%, respectively. MT imaging may be valuable in differentiating cystic infection from cystic neoplasm. J. Magn. Reson. Imaging 2000;12:395-399.

Value of magnetic resonance myelography in the diagnosis of disc herniation and spinal stenosis.

Magnetic resonance imaging provides a good-quality image over the entire length of the spine and can assess the morphology of the discs and cord. It is the imaging modality of choice in the investigation of spinal diseases. Magnetic resonance myelography (MRM) is non-invasive, has comparable sensitivity to conventional myelography in visualizing lumbar nerve roots and allows overall assessment of the spinal canal even in the presence of cerebrospinal fluid block. Seventy-two patients with pre-surgical diagnosis of disc herniation were prospectively investigated prior to surgery to determine the value of MRM in the diagnosis of disc herniation and spinal stenosis. The difference between the sensitivity and accuracy of MRI (89.0-95.6%, 89.1-95.7%) and MRM (82.4-89.0%, 82.6-89.1%) was not significant for both observers. There was no significant improvement with the addition of MRM to MRI (91.2-97.8%, 91.3-97.8%). Although MRM did not significantly improve the diagnostic accuracy of MRI, it allowed a better overall view of the dural sac and root sleeves, therefore making it easier to diagnose spinal stenosis and disc herniation in a minority of cases.

Primary intrathoracic malignant fibrous histiocytoma and angiosarcoma.

Primary intrathoracic malignant fibrous histiocytoma and angiosarcoma are rare sarcomas constituting less than 0.2% of lung cancers. The typical imaging appearance is a large, well-circumscribed, non-cavitating, non-calcified, peripheral lung mass without hilar or mediastinal lymphadenopathy. Bronchoscopy and percutaneous needle aspiration are of limited value in differential diagnosis, and thoracotomy is warranted for definitive diagnosis.

Imaging diagnosis of abdominal and pelvic sarcomas.

Sarcomas of the abdomen and pelvis are rare malignant mesenchymal neoplasms that often remain undiagnosed until they attain large size. Complete tumour resection is associated with improved patient survival. Detection and delineation of the tumour, its extent and its relationship with surrounding tissues are important for surgical planning. Radiography, barium studies, and intravenous urography are of limited value in the imaging diagnosis of abdominal and pelvic sarcomas. Ultrasound is sensitive for detecting neoplasms larger than 6 cm. Computed tomography is useful for detection, defining extent, and predicting resectability of the primary tumour, evaluation of response to treatment, and detecting recurrence and metastasis. Sarcomas are predominantly large, poorly demarcated, heterogeneous masses of muscle density with haemorrhage or necrosis.