Summary:We investigated the predictive value of sequential FDG PET before and after high-dose chemotherapy (HDT) and autologous stem cell transplantation (ASCT) in 24 patients suffering from non-Hodgkin's lymphoma (NHL). FDG PET was performed at baseline, after three cycles of induction therapy, before and after HDT with ASCT. Response assessment from sequential PET scans using standardized uptake values (SUV) was available in 22 patients at the time of transplantation. Partial metabolic response (PMR) was defined as a Ͻ25% decrease of SUV between successive PET scans. Six of seven patients who did not achieve a PMR after complete induction therapy developed lymphoma progression, while 10 of 15 patients with complete metabolic response (CMR) or PMR remained in continuous remission. Four of seven patients with less than PMR after induction therapy died vs two of 15 patients with CMR/PMR. Median progression-free and overall survival of patients with less than PMR after HDT and ASCT was 9 and 29 months, respectively. In contrast, neither conventional re-staging nor the International Prognostic Index were predictive. These data suggest that sequential quantitative PET imaging does enlarge the concept of chemosensitivity used to select patients with high-risk NHL for HDT and ASCT or to route them to alternative treatments. High-dose chemotherapy (HDT) with autologous stem cell transplantation (ASCT) has been shown to be the best available treatment in patients who have relapsed from nonHodgkin's lymphoma (NHL) after conventional chemotherapy, but who remained chemotherapy-sensitive.1 This has prompted the use of HDT with ASCT as a front-line therapy in patients with high-intermediate or high risk disease according to the International Prognostic Index.2 However, clinical results have been discrepant and additional prognostic factors are needed to predict final outcome of the patients at the time of transplantation.Positron emission tomography (PET) using the glucose analogue fluorine-18-fluorodeoxglucose (FDG) has been demonstrated to improve primary staging of lymphoma and to be more precise than conventional radiological imaging for re-staging after chemotherapy.3-7 Several groups including our own have reported the high predictive value of persisting abnormal FDG uptake for residual or recurrent disease in this context.
7-9Thus FDG-PET does have a potential role in the identification of patients requiring further intensified chemotherapy. Moreover, FDG-PET can be used as a functional and quantitative measure of tumor response to induction chemotherapy 10 and may be able to differentiate between responders and non-responders at an earlier time-point than conventional CT or MRI imaging. Preliminary results in a small patient population studied before onset of treatment and again after one and two chemotherapy cycles support this hypothesis.
11We prospectively enrolled consecutive patients with NHL who were scheduled for HDT including ASCT. Progression-free and overall survival were chosen as end points of the study....
MR-urography (MRU) and CT-urography (CTU) provide refined imaging of the upper urinary tract not achievable with conventional intravenous urography (IVU). The traditional MR-urographic technique utilizes unenhanced, heavily T2 -weighted turbo spin-echo sequences for obtaining static fluid images of the urinary tract independent of the excretory renal function. T2 -weighted MR-urograms have proved to be excellent in visualizing the dilated urinary tract, even in non-excreting kidneys. In contrast, T1 -weighted MRU reflects the excretory renal function and displays the urine flow through the upper tract after renal excretion of an intravenously administered gadolinium chelate. The gadolinium-enhanced urine is visualized with fast T1 -weighted 3D-gradient-echo sequences. The combination of gadolinium and low-dose furosemide (5 - 10 mg) is the key for achieving a uniform distribution of gadolinium in the collecting system and for avoiding susceptibility artifacts (T2*-effects) in the urine. T1 -weighted excretory MRU provides impressive urograms of both non-dilated and obstructed collecting systems in patients with normal or moderately impaired renal function. Multislice-CT-urography (MS-CTU) is also an excretory urography like T1 -weighted MRU. Furthermore, MS-CTU can be combined with low-dose furosemide for accelerated passage of excreted contrast material obviating the need for abdominal compression. CT-urography is limited by its radiation burden and the nephrotoxicity of radiographic contrast media. Combining MRU or MS-CTU with conventional MRI or CT offers several applications, e.g., diagnosis of intrinsic and extrinsic tumors. Meanwhile, MRU has replaced IVU in pediatric uroradiology and is also recommended for the assessment of renal transplants. MS-CTU may provide valuable information in chronic urolithiasis, especially if associated with a distorted urinary tract anatomy. Both MRU and MS-CTU will play an important role in modern uroradiology.
Multisegmental image reconstruction improves the quantitative assessment of left ventricular function when compared to standard image reconstruction. Multisegmental image reconstruction allows qualitative wall motion analysis.
When compared to QCA, the ability of 3D-VRT to quantitatively assess coronary artery diameters and coronary artery stenoses is insufficient for clinical purposes.
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