In vivo 31P spectroscopy by fully adiabatic extended image selected in vivo spectroscopy: a comparison between 3 T and 7 T.

An improved image selected in vivo spectroscopy (ISIS) sequence for localized (31)P magnetic resonance spectroscopy at 7 T was developed. To reduce errors in localization accuracy, adiabatic excitation, gradient offset independent adiabatic inversion pulses, and a special extended ISIS ordering scheme were used. The localization accuracy of extended ISIS was investigated in phantoms. The possible spectral quality and reproducibility in vivo was explored in a volunteer (brain, muscle, and liver). A comparison between 3 T and 7 T was performed in five volunteers. Adiabatic extended ISIS provided high spectral quality and accurate localization. The contamination in phantom experiments was only ∼5%, even if a pulse repetition time ∼ 1.2·T(1) was chosen to maximize the signal-to-noise ratio per unit time. High reproducibility was found in the calf muscle for 2.5 cm isotropic voxels at 7 T. When compared with 3 T, localized (31)P magnetic resonance spectroscopy in the human calf muscle at 7 T provided ∼3.2 times higher signal-to-noise ratio (as judged from phosphocreatine peak amplitude in frequency domain after matched filtering). At 7 T, extended ISIS allowed the performance of high-quality localized (31)P magnetic resonance spectroscopy in a short measurement time (∼3 to 4 min) and isotropic voxel sizes of ∼2.5 to 3 cm. With such short measurement times, localized (31)P magnetic resonance spectroscopy has the potential to be applied not only for clinical research but also for routine clinical practice.

Chromosome painting as a supplement to cytogenetic banding analysis in non-Hodgkin's lymphoma.

Chromosomal in situ suppression (CISS) hybridization with biotin labeled chromosome-specific libraries was performed on short-term cultures from five cases of non-Hodgkin's lymphoma (NHL). The painting analysis proceeded in three stages. First-stage CISS hybridization was done with libraries specific for chromosomes that seemed to be lost or rearranged as judged by banding analysis. Second-stage CISS included hybridization with probes specific for chromosomes that, because of banding pattern similarities, were considered to be likely candidates to have contributed unidentified chromatin blocks in the abnormal karyotype. The third and final stage was a confirmation hybridization with a library specific for the chromosome that, at the stage two analysis, was found to have donated the previously unknown chromosomal segment. The aberrant chromosomes were often more complex than the banding analysis had led us to believe. Among the rearrangements whose nature was determined by CISS hybridization were two add(1)(p36) which, in both cases, were shown to be a der(1)t(1;2)(p36;q31). This study illustrates the potential use of chromosome painting in resolving karyotypic uncertainties in NHL, and it shows that new cytogenetic subgroups may emerge when classical banding analysis is supplemented with fluorescence in situ hybridization techniques.