Wet detoxification has traditionally been seen as the most promising technology for treating chromium-contaminated sites. However, the addition of chemicals in the wet detoxification process not only increases the cost but also introduces extra pollutants. Moreover, the chromium-containing slag may be re-dissolved in the form of Cr(VI), and the increased concentration of Cr(VI) results in a serious "returning to yellow" phenomenon in the chromium-contaminated sites, causing undesirable secondary pollution. Microbial remediation is a promising technology to address the re-dissolution of chromium-containing slag after wet detoxification, and this article reviews the advances in this area. Firstly, the toxicity, current situation and conventional technologies for treating the chromium-containing slag were briefly summarized. The mechanisms of the inevitable re-dissolution of chromium-containing slag after wet detoxification were summarized. Three main mechanisms, namely bioreduction, biosorption and biomineralization, which are involved in the environmental-friendly and efficient microbial remediation technology, were reviewed. The variation of microbial species and the succession of microbial community during the bioremediation of chromium-contaminated sites were discussed. Finally, future research directions were prospected with the aim to develop long-term, stable and sustainable technologies for remediating the chromium-contaminated sites.
Biodegradation, Environmental ; Chromium/toxicity* ; Environmental Pollutants/toxicity*

Objective To investigate the value of MR DWI in the detection of early acute sacroiliitis in patients with spondyloarthritis(SpA).Methods The data of sacroiliac joint MRI were retrospectively analyzed in fifty-nine patients with inflammatory low back pain and negative plain radiographs and/or CT.T1WI,T2WI,short tau inversion recovery (STIR) and DWI images were obtained in all cases.Contrast-enhanced T1WI with fat suppression (FST1WI) images were obtained in 28 patients and follow-up MRI examinations were performed during treatment in 7 cases.Acute inflammatory lesion was defined as hyperintense signal located in subchondral or periarticular regions on STIR images and or on enhanced FST1WI.Cases were divided into acute inflammation group and non-inflammation group.Comparison was performed among STIR,enhanced FST1WI and DWI in the detection of acute inflammation by using Chi-square test.Mean ADC value was obtained from normal and inflammatory areas in acute inflammation group and from subchondral bone marrow in non-inflammation group,and t test was used for comparison of ADC values.Results Acute inflammation existed in 38 cases (72 sacroiliac joints) and acute inflammatory lesions displayed as high signal on DWI in 35 cases (67 sacroiliac joints).STIR,enhanced FST1WI and DWI showed no significant difference in the detection of acute sacroilliitis (37/38,38/38,36/38,respectively;x2=0.16,P=0.923).ADC values measured from acute inflammatory areas were significantly higher than values measured from normal area in acute inflammation group [(1.087± 0.207)× 10-3 and (0.537±0.091) × 10-3mm2/s],and values measured from subchondral bone marrow in non-inflammation group [(0.487±0.112) × 10-3mm2/s],there were significant difference (t values were 14.971 and 12.289,P＜0.01).ADC values were similar between normal area in acute inflammation group and subchondral bone marrow in non inflammation group (t=1.874,P=0.066).ADC values were (1.018±0.266) × 10-3 and (0.706±0.164) ×10-3mm2/s before and after the treatment (t=5.312,P＜0.01).Conclusions DWI is a sensitive method to display acute inflammatory lesions in sacroiliac joints.ADC values can be effectively used to quantify inflammatory lesions in acute sacroilliitis as well as in the evaluation of efficacy of treatment.

Objective To investigate the feasibility and accuracy of volumetric measurement of necrotic lesion using CT and MRI,and to assess the value of necrotic lesion volume in predicting collapse of the femoral head in patients with avascular necrosis of the femoral head(ANFH). Methods Comparison among CT,MRI and gross section was performed in 25 femoral heads of 18 patients who underwent total hip replacement for established ANFH.The volume of necrotic lesion was measured using fluid displacement.CT and MRI data were transferred to a computer to calculate the volume of necrotic lesion using software.One way ANOVA was used to compare the volumes of necrotic lesion measured by CT,MRI and gross section.A total of 62 patients (92 hips) who were diagnosed with ANFH but without collapse by CT were followed up 24 months.Student t-test was used to compare the ratio of the volumes of the necrotic lesion and entire femoral head in the hips with and without collapse and ROC curve analysis was carried out.Results CT and MRI coincided with gross section in the necrotic area,proliferative area and extralesional area.The volumes of the necrotic lesion measured by CT,MRI and gross section were ( 20.5 ± 5.2 ),( 21.4 ± 4.8 ),( 20.9 ± 5.2 ) cm3,respectively.There was no significant difference among the necrotic volumes measured by the three methods(F =0.185,P =0.831 ).In fifty-seven out of 92 hips,collapse of the femoral head occurred during the follow-up.The ratio of the volumes of the necrotic lesion and entire femoral head was higher in hips with collapse than in hips without collapse[ (34.5 ±9.3)％ vs.(23.4 ±8.4)％ ;t =5.749,P=0.000].The area under the ROC curve was 0.808. Conclusions The volume of the necrotic lesion plays an important role in the collapse of femoral head in patients with ANFH.Both CT and MRI can identify the shape and location of the necrotic lesion intuitively and stereospecifically and can determine the volume of the necrotic lesion accurately.

Objective To study the imaging findings of hip involvement and to compare the sensitivity of radiography,CT,and MRI in the identification of hip involvement in patients with ankylosing spondylitis(AS).MethodsAnteroposterior radiography of the pelvis and MRI of hip were performed in 55 patients with AS.CT scan of hip was performed in 29 of 55 patients.T1-weighted,T2-weighted,short tau inversion recovery (STIR) and three dimensional balanced turbo field echo with water selective excitation (3D-BTFE-WATS) coronal sequences of hips were obtained in all patients,of which fat-saturated contrastenhanced T1-weighted sequence was performed in 24 patients.The imaging data of 55 patients were analyzed.The chi-square test was used to analyze the sensitivity in the identification of hip involvement among radiography,CT,and MRI.ResultsAmong 110 hips in all 55 patients,abnormal changes were detected in 13 hips by radiography,85 hips by MRI.The findings of radiography included bone erosions in 13 hips,joint space narrowing in 4 hips,syndesmophytes in 5 hips.MRI revealed bone erosive destruction in 31 hips,joint space narrowing in 4 hips,joint effusion in 80 hips,subchondral bone marrow edema in 32 hips,fat accumulation of bone marrow in 28 hips,enthesitis in 21 hips.Bilateral synovial enhancement was showed in 19 of 24 patients who underwent fat-saturated contrast-enhanced T1-weighted sequence.Of the 58 hip joints in 29 patients who underwent CT examination,not only did CT show all bone erosions detected by radiography and MRI,but CT revealed bone erosive destruction that were not identified by radiography in 10 hips and by MRI in 1 hip as well.Abnormal changes were detected in 10.3％ (6/58)by radiography,27.6％ (16/58) by CT,and 77.6％ (45/58) by MRI.The sensitivity of MRI in the identification of hip involvement is higher than that of radiography and CT ( x2 =53.22 and 29.08,P ＜ 0.05 ).In addition to chronic bone structural changes,MRI depicted acute inflammatory changes which could not be detected by radiography and CT.ConclusionsMRI can detect early acute inflammatory changes of hip joint that can not be showed by radiography and CT.Effusion of joint and synovial enhancement caused by synovitis are the most common MRI findings of the hip in patients with AS.

Objective To compare X-ray,CT,and MRI in detection of abnormal sacroiliac joint changes in patients with early stage of ankylosing spondylitis (AS).Methods Fifty-three patients with clinical suspected early stage of AS underwent X-ray and MRI scan.MR scan sequences for the sacroiliac joints consisted of T1-weighted,T2-weighted,short time inversion recovery (STIR) and three dimensional balance turbo field echo with water selective excitation (3D-BTFE-WATS) in all patients.In 24 of the patients,fat-saturated contrast-enhanced T1-weighted was used.Twenty-five of 53 patients underwent CT scan.The Chi-square test was used to analyse the uniformity of bone erosions detected by X-ray,CT,and MRI.Results Of the 106 sacroiliac joints in 53 patients,16 sacroiliac joints with bone erosions were detected by X-ray and 63 sacroiliac joints by MRI.Of the 50 sacroiliac joints in 25 patients,26 sacroiliac joints with bone erosions were found by CT.With regard to the detection of bone erosions,there was no difference between CT and MRI (x2 =0.16,P ＞0.05 ) and there was significant difference between CT and X-ray or MRI and X-ray ( x2 =14.44 and 17.36,P ＜ 0.05 ).3D-BTFE-WATS was better than other sequences in detection of bone erosions.Acute inflammatory changes were determined by MRI,which included subchondral bone marrow edema in 32 patients,synovitis in 35 patients,fat depositions in 16 patients,enthesitis in 15 patients,capsulitis in 9 patients,and cartilaginous disruption in 31 patients.Conclusions MRI can detect acute inflammatory changes that can not display by X-ray and CT.Compared with radiography and CT,MRI is more useful in detection of abnormal sacroiliac joint changes in patients with early stage of AS.

Objective To investigate the application value of MR rthrography (MRA) in the diagnosis of acetabular labral tears. Methods Fifteen patients with a high degree of suspected acetabular labral tears received fluoroscope-guided injection of the contrast media into the hip joint ( hip arthrography) and fat-saturated spin-echo T1-weighted images were obtained in the coronal, sagittal, oblique-axial and radial planes. Hip arthroscopy was performed on 12 of them. Results Labral tears which were diagnosed in 11 patients by hip MRA were confirmed at hip arthroscopy. One patient showed no MRA indication of labral tear, also showed normal on arthroscopy. Tear in the anterior-superior quadrant 10 cases of 12 joints ( 12/13), posterior-superior quadrant 1 case of a joint (1/13). In 11 patients who underwent arthroscopy, hip MRA diagnosed 3 (3/13) joints labral tears in coronal planes, 10 (10/13) joints in sagittal planes and 13 (13/13) labral tears in axial-oblique and radial planes. In 15 patients with 20 hip joints, 5 cases 6 joints (6/20) with normal acetabular sublabral sulcus were performed. Conclusions MR arthrography of hip is a reliable method in the diagnosis of acetabular labral tears. Scanning method should be included fat-saturated spin-echo T1-weighted images in sagittal and oblique-axial planes or sagittal plus radial planes. The diagnosis of tor posterior-inferior quadrant should pay attention to the existence of a normal variation.

Objective To analyze the MRI characters of hemodialysis-related osteoarthropathy in long-term dialysis recipients, and to evaluate the diagnostic value of X-ray, CT, and MRI on hemodialysis-related osteoarthropathy. Methods The shoulders, hips, wrists and lumbar vertebraes of 32 patients underwent X-ray and CT examinations. Twenty-six of them received MRI examinations. Results In X-ray of 32 patients, 28 appeared osteoporosis, 11 showed bone resorption, 6 had cystic lesions, 11 had bone sclerosis, 1 had joint swelling, and 19 had soft tissue calcification. In CT of 32 patients, 32 appeared osteoporosis, 9 showed bone resorption, 12 had cystic lesions, 11 had bone sclerosis, 3 had joint swelling, and 19 had soft tissue calcification. In MRI of 26 patients, 6 appeared osteoporosis, 2 showed bone resorption, 14 showed cystic lesions, 5 had bone sclerosis, 15 had joint swelling, and 1 showed soft tissue calcification. Conclusions X-rays plain film is the first choice for the diagnosis of hemadialysis-related osteopathy, and MRI is the first choice for the diagnosis of hemedialysis-related arthropathy. CT and MRI is pretty useful in the diagnosis of hemodialysis-related osteoarthropathy.

Objective To prospectively assess the therapeutic procedure and outcome of MR-guided percutaneous sclerotherapy in patients with venous vascular malformations of the extremities. Methods Fifty-seven percutaneous sclerotherapy treatments were performed under MR guidance in 28 patients with venous vascular malformation. Assessment was conducted to analyze (1) individual success of therapy, (2) improvement of clinical symptoms, ( 3 ) occurrence of complications, (4) volume changes at follow-up examinations, (5) contrast-to -noise ration (CNR) changes. Paired-t test was used to compare the volume and CNR of pre- and postintervention. Results All MR-guided percutaneous sclerotherapy were performed successfully and without serious complications. Individual predominant symptoms were improved, especially about the pain and functional impairment. The mean lesion volumes of pre- and post-intervention were (56. 8 ± 11.7 ) cm3 and ( 27.0 ± 7.2 ) cm3 respectively, which showed significant difference ( t = 8. 90, P < 0. 01 ). The percentage of volume shrinkage ranged from 28. 5% to 74. 4% [ mean ( 54. 4 ± 5. 3 ) % ]. The CNR of the pre and post-interventional images were 21.9 ± 2. 0 and 8.4 ± 0. 9 respectively. There was significant difference(t = 21.76, P < 0.01 ) between them, and the percentages of CNR decrease were 40.0% to 78. 0% [ the mean(61.0 ± 3.6)%]. Conclusion MR-guided sclerotherapy of venous vascular malformations of the extremities is a safe and efficient technique.

Objective To evaluate CT-guided pereutaneous biopsy and fine needle aspiration in diagnosing malignant musculoskeletal tumors. Methods CT-guided percutaneous biopsy and fine needle aspiration was performed in 106 cases with suspected musculoskeletal tumor. The pathological results obtained from biopsy specimens were compared with clinical final pathological diagnoses. Results All 106 cases were finally diagnosed as suffering from malignant musculoskeletal tumors, which were proved by operation and incisional biopsy. Of 106 cases receiving CT-guided percutaneous biopsy and needle aspiration, the pathologic diagnosis obtained from this procedure was consistent with the clinical final pathological diagnosis in 89 and was "negative" in 17, with an accuracy rate of 84.0%. Conclusion CT-guided percutaneous biopsy and fine needle aspiration is a safe, simple and effective technique for the diagnosis of malignant musculoskeletal tumors, Incisional biopsy may be necessary when this procedure gives "negative" result.

Objective To evaluate the MRI findings of achilles tendon rupture. Methods The MRI data of 7 patients with achilles tendon rupture were retrospectively analysed. All 7 patients were male with the age ranging from 34 to 71 years. Routine MR scanning was performed in axial and sagittal planes, including T_1WI,T_2WI and a fat suppression MRI(SPIR).Results Among 7 patients, complete achilles tendon rupture was seen in 6 cases, partial achilles tendon rupture 1 case. The site of tendon disruption were 2.6-11.0 cm(mean 5.4 cm)proximal to the insertion in the calcaneus. The MRI findings of a partial or complete rupure of the achilles tendon included enlarged and thickened achilles tendon (7 cases),wavy lax achilles tendon(2 cases),discontinuity of some or all of its fibers and intratendinous regions of increased signal intensity(7 cases).In the cases of complete tendon rupture,the size of the tendinous gap varied from 3.0-8.0 mm,which was filled with blood and appeared as edema of increase signal intensity on T_2WI and SPIR.In all 7 patients, MR scanning showed medium signal intensity(7 cases)on T_1WI,or medium signal intensity(1 cases),medium-high signal intensity(3 cases),hish signal intensity(3 cases)on T_2WI,and medium-high singnal intensity(2 eases),high signal intensity(5 cases)on fat suppression MRI. The preachilles fat pad showed obscure in 6 cases of complete achilles tendon rupture. Conclusion MRI is an excellent method for revealing achilles tendon rupture and confirming the diagnosis.