Estimating the need for neck lymphadenectomy in submucosal esophageal cancer using superparamagnetic iron oxide-enhanced magnetic resonance imaging: clinical validation study.

BACKGROUND: In cases of thoracic esophageal cancer, multidirectional lymphatic flow from the tumor means that lymph node metastasis can occur in an area extending from the neck to the abdomen. To validate a method for limiting the performance of three-field lymphadenectomy only to patients who need it, we carried out a prospective study in which superparamagnetic iron oxide (SPIO)-enhanced lymphatic mapping was used to determine whether to perform neck lymph node dissection in patients with submucosal thoracic esophageal cancer. METHODS: A total of 22 patients with clinically submucosal thoracic squamous cell esophageal cancer, without neck lymph node metastasis, were enrolled. SPIO was endoscopically injected into the peritumoral submucosal layer, after which its appearance in lymph nodes in the neck was evaluated using magnetic resonance imaging (MRI). Neck lymph nodes were then dissected based on the SPIO-enhanced MRI lymphatic mapping. RESULTS: Influx of SPIO into lymph nodes was detected in 21 patients (95% detection rate). SPIO flowed to the neck in 8 (36%) patients. Influx of SPIO into neck lymph nodes was unilateral in five patients and bilateral in three patients, and the lymph nodes were dissected accordingly. A cancer-involved node was identified in two of those patients. In 14 patients, we did not dissect neck nodes. Patients were followed up for 6 to 47 months. The neck lymph node recurrence rate was zero, and the overall recurrence rate was 5%. CONCLUSIONS: SPIO-enhanced lymphatic mapping may be useful for estimating the need for three-field lymphadenectomy with neck dissection.

Artificial model of photosynthetic oxygen evolving complex: catalytic O2 production from water by di-mu-oxo manganese dimers supported by clay compounds.

Adsorption of [(OH(2))(terpy)Mn(mu-O)(2)Mn(terpy)(OH(2))](3+) (terpy=2,2':6',2"-terpyridine) (1) onto montmorillonite K10 (MK10) yielded catalytic dioxygen (O(2)) evolution from water using a Ce(IV) oxidant. The Mn K-edge X-ray absorption near edge structure (XANES) of the 1/MK10 hybrid suggested that the oxidation state of the di-mu-oxo Mn(2) core could be Mn(III)-Mn(IV). However the pre-edge peak in the XANES spectrum of 1 adsorbed on MK10 is different from the neat 1 powder. The kinetic analysis of O(2) evolution showed that the catalysis requires cooperation of two equivalents of 1 adsorbed on MK10. The reaction of the [(bpy)(2)Mn(mu-O)(2)Mn(bpy)(2)](3+) (bpy=2,2'-bipyridine) (2)/MK10 hybrid with a Ce(IV) oxidant evolved O(2). However, the turnover number value was less than unity for 2/MK10, showing that 2 adsorbed on MK10 does not work as a catalyst. The terminal water ligands could be an important for the catalysis by adsorbed 1. The mechanism of O(2) production by photosynthetic oxygen evolving complex is discussed based on catalytic O(2) evolution by 1 adsorbed on MK10.

Characterization and activity analysis of catalytic water oxidation induced by hybridization of [(OH(2))(terpy)Mn(mu-O)(2)Mn(terpy)(OH(2))](3+) and clay compounds.

Hybridization of [(OH(2))(terpy)Mn(mu-O)(2)Mn(terpy)(OH(2))](3+) (terpy= 2,2':6',2' '-terpyridine) (1) and mica clay yielded catalytic dioxygen (O(2)) evolution from water using a CeIV oxidant. The reaction was characterized by various spectroscopic measurements and a kinetic analysis of O(2) evolution. X-ray diffraction (XRD) data indicates the interlayer separation of mica changes upon intercalation of 1. The UV-vis diffuse reflectance (RD) and Mn K-edge X-ray absorption near-edge structure (XANES) data suggest that the oxidation state of the di-mu-oxo Mn(2) core is Mn(III)-Mn(IV), but it is not intact. In aqueous solution, the reaction of 1 with a large excess Ce(IV) oxidant led to decomposition of 1 to form MnO(4-) ion without O(2) evolution, most possibly by its disproportionation. However, MnO(4-) formation is suppressed by adsorption of 1 on clay. The maximum turnover number for O(2) evolution catalyzed by 1 adsorbed on mica and kaolin was 15 and 17, respectively, under the optimum conditions. The catalysis occurs in the interlayer space of mica or on the surface of kaolin, whereas MnO(4-) formation occurs in the liquid phase, involving local adsorption equilibria of adsorbed 1 at the interface between the clay surface and the liquid phase. The analysis of O(2) evolution activity showed that the catalysis requires cooperation of two equivalents of 1 adsorbed on clay. The second-order rate constant based on the concentration (mol g(-1)) of 1 per unit weight of clay was 2.7 +/- 0.1 mol(-1) s(-1) g for mica, which is appreciably lower than that for kaolin (23.9 +/- 0.4 mol(-1) s(-1) g). This difference can be explained by the localized adsorption of 1 on the surface for kaolin. However, the apparent turnover frequency ((kO(2))app/s(-1)) of 1 on mica was 2.2 times greater than on kaolin when the same fractional loading is compared. The higher cation exchange capacity (CEC) of mica statistically affords a shorter distance between the anionic sites to which 1 is attracted electrostatically, making the cooperative interaction between adsorbed molecules of 1 easier than that on kaolin. The higher CEC is important not only for attaining a higher loading but also for the higher catalytic activity of adsorbed 1.

Multi-shot echo-planar Flair imaging of brain tumors: comparison of spin-echo T1-weighted, fast spin-echo T2-weighted, and fast spin-echo Flair imaging.

Multi-shot echo-planar fluid-attenuated inversion-recovery (EPI-Flair) was compared with spin-echo T1-weighted (SE-T1W), fast SE T2-weighted (FSE-T2W), and fast Flair (F-Flair) in imaging brain tumors. In 32 patients with various different brain tumors, three reviewers independently evaluated image quality. Two reviewers evaluated the image quality of precontrast EPI-Flair to be significantly better than that of precontrast SE-T1W. Two reviewers evaluated the image quality of postcontrast EPI-Flair as superior to that of postcontrast SE-T1W. Artifacts on postcontrast EPI-Flair were significantly more prominent than those on postcontrast F-Flair. Multi-shot EPI-Flair appeared to be superior to SE-T1W, and almost equivalent to FSE-T2W in terms of image quality.

Visualization of anterior disc displacement in temporomandibular disorders on contrast-enhanced magnetic resonance imaging: comparison with T2-weighted, proton density-weighted, and precontrast T1-weighted imaging.

OBJECTIVE: To compare postcontrast T1-weighted imaging (T1WI+) with precontrast T1-weighted (T1WI-), T2-weighted (T2WI), and proton density-weighted imaging (ProWI) in depiction of the anterior disc displacement (ADD) in temporomandibular disorders (TMDs). STUDY DESIGN: A total of 120 joints with TMD were included in this study. Qualitatively, Receiver operating characteristic analysis was performed. Quantitatively, the ratio of the intensity in the retrodiscal tissue to intensity in the disc (intensity ratio) was measured. RESULTS: One reader achieved superior performance in visualization of ADD with T1WI+ than with the other sequences. The other reader showed superiority with T1WI+ rather than T2WI or T1WI-. The intensity ratio on T1WI+ was significantly higher than the intensity ratio on other sequences. On T1WI,+ the intensity ratio in the joints with ADD was significantly higher than that in the joints without ADD. CONCLUSION: Postcontrast T1-weighted imaging can improve the visualization of ADD in TMDs.

Visualization of lymphatic basin from the tumor using magnetic resonance lymphography with superparamagnetic iron oxide in patients with thoracic esophageal cancer.

OBJECTIVE: To evaluate magnetic resonance (MR) lymphography with submucosal injection of superparamagnetic iron oxide (SPIO) for imaging lymphatic pathways from thoracic esophageal cancer. METHODS: In 24 patients with esophageal cancer, SPIO was injected into the submucosal layer of the peritumoral region endoscopically and MR lymphography was conducted. In study 1, fast spoiled gradient-recalled acquisition using a steady-state (FSPGR) sequence was performed from the neck to the upper abdomen before and at 20, 40, and 60 minutes after injection in 10 patients. In study 2, FSPGR and spin echo T1-weighted images were obtained after injection in 14 patients. Areas scanned were the neck to the upper mediastinum and the upper abdomen. RESULTS: In study 1, at 20 minutes after injection, the signal of each lymph node appeared attenuated when compared with precontrast images. The signal-to-noise ratio in lymph nodes exhibiting influx of SPIO was significantly lower than that found on precontrast images (P < 0.0005). In study 2, influx to the neck lymph nodes was detected in 8 patients (64.3%), whereas influx to the upper abdominal lymph nodes was detected in 13 (92.9%). CONCLUSIONS: Magnetic resonance lymphography with SPIO could visualize the lymphatic pathways draining from the injection site and the location of lymph nodes exhibiting influx of SPIO in patients with thoracic esophageal cancer.

Diffusion changes in a tumor and peritumoral tissue after stereotactic irradiation for brain tumors: possible prediction of treatment response.

OBJECTIVE: Changes in apparent diffusion coefficient (ADC) in a tumor and peritumoral tissue after stereotactic irradiation (STI) were evaluated, and then the therapeutic efficacy of ADC measurement was assessed. METHODS: In 20 tumors, diffusion-weighted imaging within 1 week before and 2-4 weeks after STI was performed. The normalized ADC (nADC) was measured. The nADCs in the tumor and peritumoral region before STI were compared with those after STI and the change in tumor nADC compared with the change in tumor size. RESULTS: The nADC of the tumors was significantly higher 2-4 weeks after STI compared with that before STI. The nADC of the peritumoral regions 2-4 weeks after STI did not differ significantly from that before STI. A significant difference in the nADC at 2-4 weeks after STI was observed between the responder and nonresponder groups. CONCLUSIONS: Changes in nADC as measured by diffusion-weighted imaging can predict response to STI.

Catalytic O2 evolution from water induced by adsorption of [OH2)(terpy)Mn(mu-O)2Mn(terpy)(OH2)]3+ complex onto clay compounds.

Water oxidation to evolve O2 in photosynthesis is catalyzed by an enzyme whose active site contains a mu-oxo-bridged manganese core. Catalytic O2 evolution has been difficult to establish by manganese-oxo complexes in homogeneous aqueous solutions. The reaction of [(OH2)(terpy)MnIII(mu-O)2MnIV(terpy)(OH2)]3+ (terpy = 2,2':6',2' '-terpyridine) (1) with a CeIV oxidant leads to the decomposition of 1 to the permanganate ion without O2 evolution in an aqueous solution but catalytically produces O2 from water when 1 is adsorbed on clay compounds. 18O-labeling experiments showed that the oxygen atoms in O2 originate exclusively from water. Catalysis of O2 evolution requires cooperation of 2 equiv of 1 adsorbed on clay compounds.

Comparison of multishot echo-planar fluid-attenuated inversion-recovery imaging with fast spin-echo fluid-attenuated inversion-recovery and T2-weighted imaging in depiction of white matter lesions.

PURPOSE: To compare a multishot echo-planar fluid-attenuated inversion-recovery (EPI-FLAIR) sequence with fast spin-echo FLAIR (F-FLAIR) and fast spin-echo T2-weighted (FSE-T2W) sequences in depiction of white matter lesions. METHODS: Thirty-five patients with various white matter lesions were included in this prospective study. Two independent readers for lesion detection (lesion size, >2 mm) compared sequences quantitatively. In 22 patients, contrast was calculated between periventricular hyperintensity (PVH) and the cerebrospinal fluid (CSF). RESULTS: EPI-FLAIR revealed more lesions than FSE-T2W (p < 0.01). However, F-FLAIR revealed more lesions than EPI-FLAIR (p < 0.01). For PVH-to-CSF contrast, EPI-FLAIR demonstrated significantly higher contrast than FSE-T2W. There were no differences in PVH-to-CSF contrast between EPI-FLAIR and F-FLAIR. CONCLUSIONS: This study shows that EPI-FLAIR has distinct advantages over FSE-T2W in the depiction of white matter lesions. Although EPI-FLAIR reduces imaging time by more than 60% relative to F-FLAIR, it cannot replace F-FLAIR for the detection of lesions in the cerebral white matter.

[Sentinel lymph node after intramammary injection of superparamagnetic iron oxide].

The purpose of this study was to evaluate enhancement (signal loss) of the axillary lymph nodes on MR lymphography after intramammary injection of superparamagnetic iron oxide (Ferumoxides) for detection of the sentinel lymph node. MR lymphography was performed in a total of 11 patients with breast cancer without palpable axillary lymph node swelling before operation. Coronal and axial images were obtained before and after intramammary injection of 1.5 ml Ferumoxides adjacent to the breast tumor. In all patients, decreased intensity was recognized in the axillary lymph nodes. MR lymphography could detect the sentinel lymph node with its decreased signal intensity 20 minutes after the intramammary injection of Ferumoxides.