Publications (84) View all
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Article: Memory-provoked rCBF-SPECT as a diagnostic tool in Alzheimer's disease?
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ABSTRACT: Alzheimer's disease (AD) is a primary degenerative disease that progressively affects all brain functions, with devastating consequences for the patient, the patient's family and society. Rest regional cerebral blood flow (rCBF) could have a strategic role in differentiating between AD patients and normal controls, but its use for this purpose has a low discriminatory capacity. The purpose of this study was to evaluate whether the diagnostic sensitivity of rCBF single-photon emission computed tomography (SPECT) could be increased by using an episodic memory task provocation, i.e. memory-provoked rCBF-SPECT (MP-SPECT). Eighteen persons (73.2+/-4.8 years) with mild AD and 18 healthy elderly (69.4+/-3.9 years) were included in the study. The subjects were injected with (99m)Tc-hexamethylpropylene amine oxime (HMPAO) during memory provocation with faces and names, followed by an rCBF-SPECT study. The rCBF (99m)Tc-HMPAO SPECT images were analysed using statistical parametric mapping (SPM2). Peaks with a false discovery rate corrected value of 0.05 were considered significant. On MP-SPECT, the AD group showed a significant rCBF reduction in the left parietal cortex in comparison with healthy elderly. At rest, no significant group differences were seen. Memory provocation increased the sensitivity of rCBF-SPECT for the detection of AD-related blood flow changes in the brain at the group level. Further studies are needed to evaluate MP-SPECT as a diagnostic tool at the individual level. If a higher sensitivity for AD at the individual level is verified in future studies, a single MP-SPECT study might be sufficient in the clinical setting.European journal of nuclear medicine and molecular imaging 02/2006; 33(1):73-80. · 4.99 Impact Factor -
Article: Positive pivot shift after ACL reconstruction predicts later osteoarthrosis: 63 patients followed 5-9 years after surgery.
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ABSTRACT: Rupture of the anterior cruciate ligament (ACL) may cause osteoarthrosis (OA) and functional impairment. We wanted to find out whether the degree of knee stability obtained after ACL reconstruction correlates with radiographic and clinical outcome. We examined 63 patients 2 and 5-9 years after anterior cruciate ligament (ACL) reconstruction. Knee stability was assessed 2 years after surgery by recording AP laxity using radiostereometric technique (RSA) and by performing the pivot shift test. Degeneration of the knee joint was evaluated with bone scintigraphy, and radiographically. Functional outcome was assessed with Lysholm score, Tegner activity scale and with the one-leg hop test. Radiographic signs of osteoarthrosis at the most recent follow-up (5-9 years) did not correlate with knee stability. Patients with positive pivot shift test 2 years after surgery showed increased scintigraphic activity of the subchondral bone at the most recent follow-up, and inferior subjective functional outcome 2 years after surgery. Knees having had meniscus resections had more often OA. Radiographical signs of OA were associated with higher scintigraphic uptake in the operated knee relative to the contralateral knee. The ability to obliterate the pivoting by ACL reconstruction appears to be more important than normalizing the AP laxity in order to prevent later OA.Acta Orthopaedica Scandinavica 10/2004; 75(5):594-9. -
Article: Rotation Radius Dependence of 123I-FP-CIT and 123I-IBZM SPECT Uptake Ratios: A Monte Carlo Study.
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ABSTRACT: In dopamine brain SPECT, semiquantitative techniques are in use, mostly for research purposes, to calculate activity uptake in the striatum relative to the background. The measured uptake ratios depend on both acquisition and reconstruction, and one important parameter is the rotation radius of the γ-camera detectors, which affects spatial resolution. In brain SPECT research studies, the rotation radius is typically set to a constant value to maintain a constant resolution, but because of variations in patient anatomy and compliance, this is not always possible. METHODS: In this study, correction factors as a function of rotation radius are developed to correct the uptake ratios where the rotation radius has deviated from the reference value, 15 cm. Monte Carlo simulations of a digital brain phantom were used to produce images with a high and a low uptake ratio, and for both studies the rotation radius was varied between 14 and 23 cm. Two different methods, one based on 2-dimensional (2D) regions of interest of constant shape and size, and one based on predefined 3-dimensional (3D) volumes of interest, were used to calculate the semiquantitative uptake ratios. RESULTS: For the 2D method, the change in uptake ratio was 1.2%/cm for the high uptake ratio and 0.9%/cm for the low uptake ratio. The corresponding results for the 3D method were 2.1% and 1.7%, respectively. CONCLUSION: The 3D method was found to be more dependent on rotation radius than the 2D method, which was expected because of the 3D nature of the partial-volume effect. The correction factors were, however, less dependent on which of the 2 uptake ratios was simulated, which is positive for the application of the correction equations on patient data.Journal of Nuclear Medicine Technology 10/2012; -
Article: Sentinel node detection in renal cell carcinoma. A feasibility study for detection of tumour-draining lymph nodes.
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ABSTRACT: To evaluate the feasibility of performing sentinel node detection in patients with renal cell carcinoma (RCC). An open series of 13 arbitrarily selected patients with T1b-T3b RCC scheduled for radical nephrectomy at a single Tertiary Academic Centre were examined with different modalities of sentinel node detection. Preoperative ultrasonography-guided injection of radioactive isotope, lymphoscintigram and single photon emission computed tomography/computed tomography, followed by intraoperative gamma-probe detection and Patent Blue detection, as well as postoperative scintigram of the main specimen were the planned interventions. These investigations were performed in conjunction with intended open radical nephrectomy. In 10 of the 13 patients sentinel node detection was achieved with 32 sentinel nodes displayed. Radio-guided surgery using an intraoperative gamma-probe resulted in the highest realtive detection rate with detection of sentinel nodes in nine patients. In total, nine metastatic sentinel nodes were detected in three patients. One patient, preoperatively staged as N+, was restaged after sentinel node detection and histopathology as pN0. Sentinel node detection in renal tumours is feasible although evaluation of different modes of detection needs further refinement and standardization. All nodes preoperatively detected by routine computed tomography as suspicious metastatic lesions were confirmed as sentinel nodes, including two nodes considered as metastatic by preoperative routine imaging but ultimately staged as non-metastatic sentinel nodes.BJU International 08/2011; 109(8):1134-9. · 2.84 Impact Factor -
Article: H HRMAS NMR Derived Bio-markers Related to Tumor Grade, Tumor Cell Fraction, and Cell Proliferation in Prostate Tissue Samples.
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ABSTRACT: A high-resolution magic angle spinning NMR spectroscopic approach is presented for evaluating the occurrence, amount and aggressiveness of cancer in human prostate tissue samples. Using this technique, key metabolites in malignant and non-malignant samples (n = 149) were identified, and patterns of their relative abundance were analyzed by multivariate statistical methods. Ratios of various metabolites - including (glycerophophorylcholine + phosphorylcholine)/creatine, myo-inositol/scyllo-inositol, scyllo-inositol/creatine, choline/creatine, and citrate/creatine - correlated with: i) for non-malignant tissue samples, the distance to the nearest tumor and its Gleason score and; ii) the fraction of tumor cells present in the sample; and iii) tumor cell proliferation (Ki67 labelling index). This NMR-based approach allows the extraction of information that could be useful for developing novel diagnostic methods for prostate cancer.Biomarker insights 01/2011; 6:39-47.
