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Victor Kalff

Publications and source records attributed to Victor Kalff.

10 recordsLinked to original sources
PubMed2006

Findings on 18F-FDG PET scans after neoadjuvant chemoradiation provides prognostic stratification in patients with locally advanced rectal carcinoma subsequently treated by radical surgery.

UNLABELLED: Predicting outcome after aggressive therapy for advanced rectal cancer remains difficult. (18)F-FDG PET has emerged as a valid method for predicting patient outcomes after therapy in an increasing number of cancers. We evaluated the prognostic information obtained from the degree of change in tumor (18)F-FDG PET uptake induced by chemoradiation before radical curative surgery in patients with T3/T4 rectal cancer. METHODS: The study included 34 consecutive patients with T3/T4 Nx M0 rectal cancer on structural imaging, who underwent staging and postchemoradiation (18)F-FDG PET before planned curative surgery. Change in (18)F-FDG uptake was graded visually as complete (CMR), partial (PMR), or no (NoMR) metabolic response. Pre- and postchemoradiation (18)F-FDG PET-derived standardized uptake values (SUVs) were then obtained for PMR patients to determine whether SUV further stratified this subgroup. Operative findings were available in 30 patients (3 excluded because of (18)F-FDG PET-defined M1 disease, 1 refused surgery). Clinical status at study closeout (alive free from disease, FFD; alive with disease, AWD; or died of disease, DOD) was available for all patients. RESULTS: A pathologic complete response was found in only 6 of 30 patients (5 CMR, 1 false-positive PMR). However, after an estimated median 3.1 y of follow-up, all 17 CMR patients were FFD, 6 of 10 PMR patients were FFD, 2 of 10 had DOD, and 2 of 10 were AWD. All 3 NoMR patients DOD. PET response was highly significantly associated with overall survival duration (P < 0.0001) and time to progression (P < 0.0001). Pathologic complete response was the only other statistically significant prognostic factor (P < 0.03). The percentage of maximum SUV change after chemoradiation was not predictive of survival in PMR patients. CONCLUSION: Using a simple qualitative assessment, postchemoradiation (18)F-FDG PET scintigraphy provides good medium-term prognostic information in patients with advanced rectal cancer undergoing radical surgery with curative intent.

Adult↗
PubMed2004

Does positron emission tomography change management in primary rectal cancer? A prospective assessment.

PURPOSE: The influence of positron emission tomography in the management of recurrent rectal cancer is well established but its role in primary rectal cancer remains uncertain. This study therefore prospectively assesses the impact of position emission tomography scanning on the management of primary rectal cancer. METHODS: Forty-six patients with advanced primary rectal cancer referred for consideration of adjuvant preoperative therapy underwent position emission tomography scanning. The referring physicians prospectively recorded each patient's stage following conventional imaging and the proposed treatment plan prior to position emission tomography scanning. This was then compared with subsequent stage and actual management implemented, and the appropriateness of position emission tomography-induced changes was noted by subsequent clinical follow-up. RESULTS: The surgical management of 36 of 46 patients (78 percent) was unchanged as a result of position emission tomography, even though position emission tomography upstaged disease in 3 of 36 cases (8 percent) and downstaged disease in 5 of 36 cases (14 percent). In 8 of 46 cases (17 percent), management was altered because of the position emission tomography scan findings, including 6 cases (13 percent) in which surgery was cancelled and 2 other cases (4 percent) in which the radiotherapy field was changed. Where available, follow-up confirmed the appropriateness of position emission tomography-induced management change in each case. Two patients had a change in therapy independent of the position emission tomography scan due to clinical circumstances. Overall tumor stage was changed following position emission tomography in 18 of 46 patients (39 percent). CONCLUSION: Position emission tomography scanning appears to accurately change the stage or appropriately alter the therapy of almost a third of patients with advanced primary rectal cancer. In view of this, we suggest that position emission tomography scanning be considered part of standard workup for such patients, particularly if neoadjuvant chemoradiation is being considered as part of primary management.

Adult↗
PubMed2004

Demonstrating time sequence and extent of sustained decrease in native heart ejection fraction after heterotopic transplantation.

BACKGROUND: In this study we investigate the time sequence and extent of the sustained decrease in native heart ejection fraction (EF) after heterotopic heart transplantation (HHTx) when using gated cardiac blood pool scanning (GCBPS) and transthoracic echocardiography (TTE) One case report of 2 patients used post-operative GCBPS and TTE and found a significant deterioration in native heart EF post-operatively over the course of several years. Comparison with pre-operative measurements using these techniques in a series of patients has not been performed previously. METHODS: Thirteen of 16 HHTx patients with adequate pre- and post-operative GCBPS follow-up were included in this study. All patients also underwent TTE post-operatively and the GCBPS results were correlated with the TTE findings. RESULTS: GCBPS demonstrated a marked (21.1 +/- 4.7% vs 10.5 +/- 3.7%, p < 0.0001) decrease in native EF post-HHTx. Spontaneous echo contrast in the native left ventricle and/or poor opening of the mitral/aortic valves was noted at Day 1 in 4 of 5 patients who had a TTE at this stage. No further decline was noted between the first and last post-operative GCBPS (10.8 +/- 3% vs 8.6 +/- 2.1%, p = NS). CONCLUSIONS: A dramatic decrease in native heart EF post-HHTx occurs as early as Day 1 post-transplant. Dissociation of ventricular contraction is the most likely cause. Studies have demonstrated that paced linkage (counterpulsation) between the ventricles results in improved hemodynamics. This may have clinical implications as to the timing of ejection of blood from a left ventricular assist device (LVAD) and for providing the best hemodynamics for the ventricle being assisted and for optimizing its chances of long-term recovery.

Echocardiography↗
PubMed2003

Relation of local platelet glycoprotein IIb/IIIa independent activation during coronary angioplasty in acute myocardial infarction to recovery of left ventricular function.

We assessed glycoprotein (GP) IIb/IIIa independent platelet activation in coronary sinus and peripheral blood from patients who underwent angioplasty for acute myocardial infarction and stable angina. Despite complete blockade of the activated GP IIb/IIIa receptor with abciximab in patients with acute myocardial infarction, unsuppressed local GP IIb/IIIa independent activation was associated with a lack of recovery of left ventricular function.

Angioplasty, Balloon, Coronary↗
PubMed2003

The potential for bronchoscopic lung volume reduction using bronchial prostheses: a pilot study.

STUDY OBJECTIVES: Significant morbidity and mortality offset the benefits of lung volume reduction surgery (LVRS) for emphysema. By contributing to distal lung collapse, bronchoscopic placement of valved prostheses has the potential to noninvasively replicate the beneficial effects of LVRS. The purpose of this study was to investigate the safety and feasibility of placing valves in segmental airways of patients with emphysema. DESIGN: Case series. SETTING: Tertiary hospital, severe airways disease clinic. PATIENTS: Ten patients aged 51 to 69 years with apical emphysema and hyperinflation, otherwise suitable for standard LVRS. Mean preoperative FEV(1) was 0.72 L (19 to 46% predicted), and 6-min walk distance was 340 m (range, 245 to 425 m). INTERVENTION: Apical, bronchoscopic, segmental airway placement of one-way valves (silicone-based Nitinol bronchial stent; Emphasys Medical; Redwood City, CA) under general anesthesia. Placement was over a guidewire under bronchoscopic and fluoroscopic control. RESULTS: Four to 11 prostheses per patient took 52 to 137 min to obstruct upper-lobe segments bilaterally. Inpatient stay was 1 to 8 days. No major complications were seen in the 30-day study period. Minor complications included exacerbation of COPD (n = 3), asymptomatic localized pneumothorax (n = 1), and lower-lobe pneumonia (day 37; n = 1). Symptomatic improvement was noted in four patients. No major change in radiologic findings, lung function, or 6-min walk distance was evident at 1 month, although gas transfer improved from 7.47 +/- 2.0 to 8.26 +/- 2.6 mL/min/mm Hg (p = 0.04) and nuclear upper-lobe perfusion fell from 32 +/- 10 to 27 +/- 9% (mean +/- SD) [p = 0.02]. CONCLUSION: Bronchoscopic prostheses can be safely and reliably placed into the human lung. Further study is needed to explore patient characteristics that determine symptomatic efficacy in a larger patient cohort.

Aged↗
PubMed2002

Evaluation of high-risk melanoma: comparison of [18F]FDG PET and high-dose 67Ga SPET.

Recently the potential of whole-body positron emission tomography scanning using 18F-fluorodeoxyglucose (FDG PET) has led to renewed interest in the use of functional imaging for the detection of occult metastatic melanoma. This study compared dedicated FDG PET with high-dose gallium-67 imaging incorporating whole-body scanning and comprehensive single-photon emission tomography (SPET) in 122 cases (121 patients) in which the two scans were performed <6 weeks apart. All patients were at high clinical risk of occult metastatic disease and 49 (40%) had abnormality suggestive of metastatic disease by at least one functional imaging technique. Discrepant scan findings were followed up to determine which technique more accurately reflected disease status. There were 23/122 (19%; 95% CI: 12%-26%) cases with discordant scan results in respect of either the presence of melanoma (11 cases) or the extent of disease (12 cases). PET correctly identified more disease than 67Ga SPET in 14 cases (including three incidental primary tumours) and was true negative in three further patients with abnormal 67Ga SPET. There were six patients with true positive 67Ga SPET in whom FDG PET was false negative (one small cutaneous deposit, one residual axillary node rated equivocal on FDG PET due to postoperative changes, one adrenal metastasis inseparable from renal activity on FDG PET and three cases in which sites missed on FDG PET were seen on 67Ga SPET. Thus, FDG PET provided incremental diagnostic information compared with 67Ga SPET in 17/23 patients, while 67Ga SPET provided incremental information compared with PET in 6/23 cases ( P=0.035). Based on Australian Medicare reimbursement levels, the net cost per patient with clinical management benefit of replacing 67Ga SPET with FDG PET was estimated to be less than EUR 1,750. These results suggest that FDG PET provides incremental and clinically important information in around 10% of patients at a low incremental cost which, combined with greater patient convenience and lower radiation dosimetry, make FDG PET the functional imaging technique of choice for evaluation of suspected metastatic melanoma.

Adult↗
PubMed2002

The clinical impact of (18)F-FDG PET in patients with suspected or confirmed recurrence of colorectal cancer: a prospective study.

UNLABELLED: This prospective study aimed to confirm, in a clinical setting, the benefits suggested by earlier retrospective studies of (18)F-FDG PET scanning for the evaluation of patients with suspected recurrence of colorectal cancer. METHODS: The referring oncologist was asked to prospectively assign a treatment plan for 102 consecutive patients being evaluated by (18)F-FDG PET for suspected or confirmed recurrence of colorectal cancer and without evidence of unresectable disease on conventional staging investigations, including CT. This treatment plan was then compared with that based on incremental information supplied by PET. Management changes were validated by follow-up. RESULTS: For 6 patients, the oncologist would not commit to a management plan without access to PET information, and for all these patients, PET correctly guided management. Of the remaining 96 patients, the management plan for 54 (56%) was altered as a direct result of unexpected PET findings. Thus, PET directly influenced management in 60 (59%) of 102 patients. The discrepant PET results could be validated in 57 patients and were correct for both the presence and the extent of malignant disease in 52 (91%) of these patients but were false-positive in 1 patient because of a pelvic abscess and underestimated the extent of metastatic disease in 4 (7%). Relapse was confirmed in 49 (98%) of 50 evaluable patients with positive PET findings. Significantly, planned surgery was abandoned in 26 (60%) of 43 patients because of incremental PET findings. Of the 42 patients for whom management was not changed by PET findings, false-negative PET findings were documented for 5 (4 with metastases < 1 cm), and the PET findings for 1 were presumed to be false-positive because of sarcoidosis. CONCLUSION: This prospective study confirms the high impact, suggested by previous retrospective analyses, of (18)F-FDG PET on management of patients with suspected recurrent colorectal cancer. The major benefit of PET is avoidance of inappropriate local therapies by documentation of widespread disease.

Adult↗
PubMed2002

Effect of mechanically simulated diaphragmatic respiratory motion on myocardial SPECT processed with and without attenuation correction.

UNLABELLED: The goal of this study was to assess the effect of diaphragmatic respiratory motion on inferior wall cold artifact in myocardial SPECT and to assess the ability of attenuation correction (AC) to correct for this artifact in the presence of diaphragmatic motion. METHODS: We used an anthropomorphic phantom with ventricular wall activity, variable ventricular caudal tilt, attenuating liver and spleen cold inserts, and variable vertical (diaphragmatic) motion amplitude and pattern. Cardiac SPECT images were acquired on a gamma camera with dual scanning transmission line sources and commercially available AC software (with scatter correction and iterative reconstruction). The acquired data were processed either using filtered backprojection or with the AC software. The resulting myocardial activity maps were processed with polar plots and with standardized inferior-to-anterior and anterior-to-lateral wall ratios. RESULTS: Subdiaphragmatic attenuation reduces inferior wall counts and this component of inferior wall artifact is fully corrected by AC relative to anterior wall counts both with and without diaphragmatic respiratory motion. In the phantom, diaphragmatic motion artifact manifests as reduction in relative count density in both the anterior wall and the inferior wall relative to the lateral wall, which is not corrected by AC. This artifact becomes more marked with increasing respiratory amplitude and its symmetry depends on the pattern of diaphragmatic motion. CONCLUSION: Images with AC acquired at small respiratory amplitudes (approximately 2 cm) in the phantom resemble images with AC found in published normal patient databases. These results support a clinical need for respiratory gating of myocardial SPECT images.

Adult↗
PubMedDate not supplied

Contributions of subdiaphragmatic activity, attenuation, and diaphragmatic motion to inferior wall artifact in attenuation-corrected Tc-99m myocardial perfusion SPECT.

BACKGROUND: Subdiaphragmatic activity and diaphragmatic motion both contribute to inferior wall artifacts in technetium 99m myocardial perfusion single photon emission computed tomography (SPECT). METHODS AND RESULTS: We used an anthropomorphic phantom with ventricular wall activity, liver/spleen inserts containing variable Tc-99m activity, and variable vertical (diaphragmatic) motion amplitude. SPECT and transmission scans were obtained on a GE Optima NX camera. Data were processed by use of filtered backprojection or attenuation correction (AC). Resulting myocardial activity maps were analyzed with standardized inferior-anterior and anterior-lateral wall ratios. At a subdiaphragmatic-myocardial activity ratio of 0.5:1, inferior wall attenuation predominates, producing a cold artifact. AC corrects inferior wall activity to the level of the anterior wall irrespective of diaphragmatic motion. At a subdiaphragmatic-myocardial activity ratio of 1:1, inferior wall counts vary widely depending on the proximity of subdiaphragmatic activity to the ventricle. With increasing diaphragmatic amplitude, the overlap of subdiaphragmatic activity and inferior wall worsens, leading to a complex mixture of cold and hot artifacts, not corrected by AC. CONCLUSIONS: Concentration and proximity of subdiaphragmatic Tc-99m activity relative to myocardium comprise a major factor in the nature and severity of inferior wall artifacts. If the subdiaphragmatic Tc-99m concentration is equivalent to that in the myocardium, complex, potentially uninterpretable hot and cold inferior wall artifacts are produced.

Artifacts↗