Purpose:To investigate the possibility of using combined blood oxygen level-dependent (BOLD) imaging and diffusion-weighted imaging (DWI) to detect pathological and physiological changes in renal tissue damage of the kidney induced by chronic renal hyperfiltration. Materials and Methods:The apparent diffusion coefficient (ADC) and the T 2 * value within the inner compartments of the kidneys of 17 rats with diabetes mellitus were compared with the results obtained from a control group (N ϭ 16). The influence of dynamic changes of the renal function on the blood-oxygen saturation was evaluated by comparing the T 2 * values before and after the active reduction of tubular transport by furosemide injection.Results: All compartments of the diabetic kidney showed significantly (P Ͻ 0.05) lower T 2 *-values compared to the control group. In particular, the very low values in the outer stripe (OS) of the outer medulla (OM) (T 2 *-normal: 69.4 Ϯ 10.9 msec; T 2 *-diabetic: 51.4 Ϯ 13.9 msec) indicated either hypoxia due to hyperfiltration, or renal blood volume changes. Diffusion imaging of the same area showed significantly lower ADC values (ADC-normal: 1.45 Ϯ 0.26; ADCedema: 1.19 Ϯ 0.25 [10 -9 m 2 /s]) that correlated with pathological findings on histopathology. The injection of furosemide significantly (P Ͻ 0.05) increased T 2 * in all compartments of both populations while the ADC remained unchanged.Conclusion: BOLD-contrast imaging appears to be able to depict tissue at risk from ischemia by revealing information about the balance between tubular workload and delivery of oxygen, and thus may reflect a measure of the reserve capacity. The diffusion measurements apparently reveal complementary information. Although ADC imaging is not sensitive to the current energy metabolism, it appears toreflect the pathological changes within the tissue. Therefore, ADC measurements may be a sensitive indicator of the severity of ischemic lesions.

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Intravenously injected MSCs specifically home to focal areas of glomerular damage and can be detected at ex vivo MR imaging.

BACKGROUNDIdentification of the alveolar subtype of rhabdomyosarcoma (ARMS) is important, because the poor prognosis associated with this subtype necessitates a modified therapeutic regimen. At present, ARMS diagnoses are made on the basis of histologic findings and the extent of myogenin immunopositivity. Nonetheless, the absence of an alveolar pattern in the solid variant, the low degree of differentiation in certain embryonal rhabdomyosarcomas (ERMS), and the increasing use of microbiopsy samples make the diagnosis of ARMS somewhat difficult. Two specific translocations have been found in ARMS, and fusion transcripts can be detected by reverse transcriptase–polymerase chain reaction (RT‐PCR) analysis of paraffin‐embedded tissue (PET).METHODSTo assess the value of myogenin staining and molecular testing in the diagnosis of rhabdomyosarcoma, the authors examined 109 rhabdomyosarcoma samples (45 ARMS samples and 64 ERMS samples). Real‐time RT‐PCR analysis of PET was performed in all 109 rhabdomyosarcomas, and RT‐PCR analysis of frozen material was performed in 24 cases.RESULTSPAX fusion transcripts were present in 44 cases (39 ARMS and 5 ERMS) and absent in 52 cases (2 ARMS and 50 ERMS). In 13 cases (4 ARMS and 9 ERMS), the results were not interpretable. Results were concordant between paired frozen and fixed tumor samples. All 35 interpretable ERMS samples that contained < 50% myogenin‐positive cells failed to yield detectable PAX fusion transcripts. Of the 61 interpretable tumor samples (41 ARMS and 20 ERMS) that contained > 50% myogenin‐positive cells, 44 (39 ARMS and 5 ERMS) yielded detectable PAX fusion transcripts.CONCLUSIONSThe current study demonstrates that molecular detection of PAX fusion transcripts via real‐time RT‐PCR analysis of PET is a sensitive and specific method for the diagnosis of ARMS and that immunohistochemical analysis of myogenin expression can be used to select cases for such molecular testing. Although RT‐PCR analysis appears not to possess diagnostic value in tumors with < 50% tumor cell immunopositivity, it is strongly recommended for the diagnosis of tumors containing > 50% myogenin‐positive cells. Cancer 2004. © 2004 American Cancer Society.

Twenty-four-hour delayed USPIO-enhanced MR imaging may help identify and differentiate various types of nephropathies.