Application of diffusion tensor imaging for the diagnosis of segmental level of dysfunction in cervical spondylotic myelopathy.

STUDY DESIGN: A retrospective study. OBJECTIVES: Diffusion tensor imaging (DTI) reflects pathological change in the spinal cord more sensitively than conventional magnetic resonance imaging (MRI). Electrophysiological examination enables quantitative assessment of spinal cord function. Few studies have addressed the correlation between intraoperative spinal cord-evoked potentials (SCEPs) and DTI. The purpose of this study was to examine whether DTI is an objective index for the diagnosis of the segmental level of dysfunction in cervical spondylotic myelopathy (CSM). SETTING: Yamaguchi University Graduate School of Medicine, Japan. METHODS: Using 3.0-Tesla MRI, DTI values for the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured at the disc level C2/C3 through C6/C7 in 11 normal subjects and 10 subjects with CSM. Subjects with CSM were divided into two groups based on the extent of compression according to conventional MRI: single level (n=3) and multilevel (n=7). Intraoperative SCEPs were measured in subjects with CSM. For each group, the ADC and FA values were compared with SCEPs with respect to the segmental levels of dysfunction. RESULTS: For all three subjects with single-level compression and six of seven with multilevel compression, the maximal ADC value was observed at the segmental level of dysfunction as per the SCEP. Minimum FA values were observed at those sites in two of three patients with single-level compression and in only two of seven with multi-level compression. CONCLUSION: Our results suggest that ADC might serve as a supplementary diagnostic indicator of the segmental levels of dysfunction in CSM.

The luteinising hormone surge-generating system is functional in male goats as in females: involvement of kisspeptin neurones in the medial preoptic area.

A luteinising hormone (LH) surge is fundamental to the induction of ovulation in mammalian females. The administration of a preovulatory level of oestrogen evokes an LH surge in ovariectomised females, whereas the response to oestrogen in castrated males differs among species; namely, the LH surge-generating system is sexually differentiated in some species (e.g. rodents and sheep) but not in others (e.g. primates). In the present study, we aimed to determine whether there is a functional LH surge-generating system in male goats, and whether hypothalamic kisspeptin neurones in male goats are involved in the regulation of surge-like LH secretion. By i.v. infusion of oestradiol (E2; 6 µg/h) for 16 h, a surge-like LH increase occurred in both castrated male and ovariectomised female goats, although the mean peak LH concentration was lower and the mean peak of the LH surge was later in males compared to females. Dual staining with KISS1 in situ hybridisation and c-Fos immunohistochemistry revealed that E2 treatment significantly increased c-Fos expression in the medial preoptic area (mPOA) KISS1 cells in castrated males, as well as ovariectomised females. By contrast, dual-labelled cells were scarcely detected in the arcuate nucleus (ARC) after E2 treatment in both sexes. These data suggest that kisspeptin neurones in the mPOA, but not those in the ARC, are involved in the induction of surge-like LH secretion in both male and female goats. In summary, our data show that the mechanism that initiates the LH surge in response to oestrogen, the mPOA kisspeptin neurones, is functional in male goats. Thus, sexual differentiation of the LH surge-generating system would not be applicable to goats.

Oestrogen-induced activation of preoptic kisspeptin neurones may be involved in the luteinising hormone surge in male and female Japanese monkeys.

The oestrogen-induced luteinising hormone (LH) surge is evident in male primates, including humans, whereas male rodents never show the LH surge, even when treated with a preovulatory level of oestrogen. This suggests that the central mechanism governing reproductive hormones in primates is different from that in rodents. The present study aimed to investigate whether male Japanese monkeys conserve a brain mechanism mediating the oestrogen-induced LH surge via activation of kisspeptin neurones. Adult male and female Japanese monkeys were gonadectomised and then were treated with oestradiol-17ß for 2 weeks followed by a bolus injection of oestradiol benzoate. Both male and female monkeys showed an oestrogen-induced LH surge. In gonadectomised monkeys sacrificed just before the anticipated time of the LH surge, oestrogen treatment significantly increased the number of KISS1-expressing cells in the preoptic area (POA) and enhanced the expression of c-fos in POA KISS1-positive cells of males and females. The oestrogen treatment failed to induce c-fos expression in the arcuate nucleus (ARC) kisspeptin neurones in both sexes just prior to LH surge onset. Thus, kisspeptin neurones in the POA but not in the ARC might be involved in the positive-feedback action of oestrogen that induces LH surge in male Japanese monkeys, as well as female monkeys. The present results indicate that oestrogen-induced activation of POA kisspeptin neurones may contribute to the LH surge generation in both sexes. The conservation of the LH surge generating system found in adult male primates, unlike rodents, could be a result of the capability of oestrogen to induce POA kisspeptin expression and activation.

Dynamic imaging of pancreatic diseases by contrast enhanced coded phase inversion harmonic ultrasonography.

BACKGROUND: Coded phase inversion harmonic ultrasonography, a newly available sonographic technique, enables visualisation of slow flow in minute vessels in a real time fashion with the use of a sonographic contrast agent containing monosaccharide. Our purpose was to employ this novel technique to observe microvessels in pancreatic tumours. SUBJECTS AND METHODS: Sixty five patients with suspicious pancreatic tumours received contrast enhanced coded phase inversion harmonic ultrasonography, contrast enhanced computed tomography, and endosonography. Final diagnoses based on histological findings were pancreatic ductal carcinomas in 49 patients, inflammatory pseudotumours with chronic pancreatitis in seven, and endocrine tumours in nine. For contrast enhanced coded harmonic ultrasonography, Levovist, a contrast agent, was injected intravenously as a bolus. When the first microbubble signal appeared in the pancreas, images of the ideal scanning plane were displayed in a real time continuous fashion (vessel images). Subsequently, interval delay scanning (perfusion images) was taken to demonstrate parenchymal flow. Tumour vascularity was evaluated by using the two types of imaging. Sensitivities for depicting pancreatic tumours were compared between three examinations. RESULTS: Contrast enhanced ultrasonography demonstrated tumour vessels in 67% of pancreatic ductal carcinomas, although most were relatively hypovascular compared with the surrounding pancreatic tissue. The vascular patterns of tumours obtained by contrast enhanced ultrasonography were closely correlated with those obtained by contrast enhanced computed tomography. Values for sensitivity in depicting pancreatic tumours of 2 cm or less in size were 68% for contrast enhanced computed tomography, 95% for endosonography, and 95% for contrast enhanced ultrasonography. CONCLUSION: Contrast enhanced coded phase inversion harmonic ultrasonography successfully visualised fine vessels in pancreatic tumours and may play a pivotal role in the depiction and differential diagnosis of pancreatic tumours.

Evaluation of posttreatment response of hepatocellular carcinoma with contrast-enhanced coded phase-inversion harmonic US: comparison with dynamic CT.

PURPOSE: To assess the reliability of contrast material-enhanced real-time gray-scale ultrasonography (US) in evaluating posttreatment response of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Fifty HCC nodules were examined with contrast-enhanced coded phase-inversion harmonic US before and after treatment. Intratumoral vascularity was assessed with continuous imaging in the early arterial phase and with interval-delay scanning to depict tumor parenchymal flow during the blood pool phase. Vascular findings at US were compared with those at dynamic computed tomography (CT). RESULTS: In 50 HCC nodules before treatment, positive enhancement of tumor vessels and tumor parenchymal flow (stain) were observed in 47 (94%) and 46 (92%), respectively. Either tumor vessel or stain was visualized with coded harmonic US in 49 of 50 nodules. Eighty-one coded harmonic US studies were performed in 49 posttreatment HCC nodules. Compared with dynamic CT, the sensitivity, specificity, and accuracy of coded harmonic US in helping to detect positive enhancement in pretreatment HCC were 98% (49 of 50), 100% (50 of 50), and 98% (49 of 50), respectively. After treatment, positive enhancement of tumor vascularity was observed in 39 (48%) of 81 posttreatment studies, and no enhancement was observed in others (52%). Coded harmonic US demonstrated partial and no enhancement of tumor vascularity in four and one nodule, respectively; after transcatheter arterial embolization with iodized oil, evaluation of tumor vascularity with dynamic CT was difficult because of the presence of oil. CONCLUSION: With enhancement, coded harmonic US depicted tumor vascularity by showing tumor vessels in a real-time fashion at continuous imaging and tumor parenchymal flow at interval-delay scanning.

Hepatocellular carcinoma: depiction of tumor parenchymal flow with intermittent harmonic power Doppler US during the early arterial phase in dual-display mode.

PURPOSE: To assess the effectiveness of contrast material-enhanced intermittent harmonic Doppler ultrasonography (US) in depicting tumor vessels and tumor parenchymal flow (stain) in hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Fifty-eight patients with 65 HCC nodules were examined by using intermittent harmonic power Doppler US and digital subtraction harmonic B-mode US, both with intravenous administration of SH U 508A. Vascular findings at early arterial phase harmonic US were classified as positive enhancement or nonenhancement, depending on the tumor vascularity relative to the surrounding liver parenchyma. These results were compared with those of three-phase helical dynamic computed tomography (CT). RESULTS: For hypervascular HCCs, there was excellent depiction of tumor vessels and tumor stain with the two intermittent harmonic US methods. The sensitivity and specificity for depiction of tumor vascularity were 93% (41 of 44 nodules) and 100% (21 of 21), respectively, with intermittent harmonic power Doppler US and 86% (38 of 44) and 100% (21 of 21), respectively, with subtraction US, as compared with these values at dynamic CT. Attenuation was an important factor in the depictability of tumor vascularity at harmonic US. CONCLUSION: Contrast-enhanced intermittent harmonic US enables noninvasive demonstration of tumor vessels and especially tumor stain in HCC.

Contrast-enhanced subtraction harmonic sonography for evaluating treatment response in patients with hepatocellular carcinoma.

OBJECTIVE: Our objective was to assess the usefulness of contrast-enhanced subtraction harmonic sonography in evaluating the treatment response of patients with hepatocellular carcinoma. SUBJECTS AND METHODS: Thirty-two hepatocellular carcinoma lesions in 26 patients (age range, 44-85 years; mean age, 66 years) were examined with Levovist-enhanced intermittent harmonic imaging before and after therapy. A Toshiba Powervision 8000 was used. A subtraction image was obtained by digitally subtracting the last-frame harmonic image from the first-frame image when multishot mode was preset. Results of contrast-enhanced CT were compared with the results of subtraction harmonic imaging. RESULTS: Before therapy, an enhancement pattern of tumor vascularity was seen for 93.8% (30/32) of hepatocellular carcinoma nodules on subtraction harmonic imaging. After therapy, subtraction harmonic imaging showed 46.7% (14/30) enhancement (incomplete tumor necrosis) and 53.3% (16/30) no enhancement (complete tumor necrosis). When dynamic CT was the gold standard, the sensitivity, specificity, and accuracy of subtraction harmonic imaging were 93.3%, 100%, and 96.7%, respectively. Intratumoral flow signals in hepatocellular carcinoma after therapy on harmonic imaging were used as a guide to target additional percutaneous therapy. CONCLUSION: Digital subtraction contrast-enhanced harmonic imaging can depict tumor vascularity in hepatocellular carcinoma after therapy sensitively and accurately. Because it is easy to perform and provides real-time needle insertion guidance, it may be preferable to perform after localized therapy to monitor treatment response, which will reduce unnecessary CT scanning.