Arthur van Lingen

Prediction of recovery of myocardial dysfunction after revascularization comparison of fluorine-18 fluorodeoxyglucose/thallium-201 SPECT, thallium-201 stress-reinjection SPECT and dobutamine echocardiography

OBJECTIVES We compared three techniques to predict functional recovery after revascularization. BACKGROUND Recently, fluorine-18 (F-18) fluorodeoxyglucose in combination with single-photon emission computed tomography (SPECT) has been proposed to identify viable myocardium, Thallium-201 reinjection and low dose dobutamine echocardiography are used routinely for this purpose. METHODS Seventeen patients (mean [+/- SD] left ventricular ejection fraction 36 +/- 11%) were studied. Regional and global ventricular function were evaluated before and 3 months after revascularization by echocardiography and radionuclide ventriculography, respectively. Myocardial F-18 fluorodeoxyglucose uptake (during hyperinsulinemic glucose clamping) was compared with rest perfusion assessed with early thallium-201 SPECT. On a separate day, low dose dobutamine echocardiography and post-stress thallium-201 reinjection SPECT were simultaneously performed. RESULTS The sensitivities for F-18 fluorodeoxyglucose/thallium-201, thallium-201 reinjection and low dose dobutamine echocardiography to assess recovery were 89%, 93% and 85%, respectively; specificities were 77%, 43% and 63%, respectively. Stepwise logistic regression indicated that F-18 fluorodeoxyglucose/ thallium-201 was the best predictor. In hypokinetic segments, the combination of F-18 fluorodeoxyglucose/thallium-201 and low dose dobutamine echocardiography was the best predictor. Global function improved (left ventricular ejection fraction increased > 5%) in 6 patients and remained unchanged in 11. All three techniques correctly identified five of six patients with improvement. Fluorine-18 fluorodeoxyglucose/thallium-201 identified all patients without improvement; low dose dobutamine echocardiography identified 9 of 11 without improvement; and thallium-201 reinjection identified 6 of 11 patients without improvement. CONCLUSIONS Fluorine-18 fluorodeoxyglucose/thallium-201 SPECT was superior to the other techniques in assessing functional recovery. Integration of metabolic and functional data is necessary, particularly in hypokinesia, for optimal prediction of improvement of regional function.

Prediction of improvement of contractile function in patients with ischemic ventricular dysfunction after revascularization by fluorine-18 fluorodeoxyglucose single-photon emission computed tomography

OBJECTIVES We evaluated the use of fluorine-18 fluorodeoxyglucose (FDG) and single-photon emission computed tomography (SPECT) to predict improvement of left ventricular ejection fraction (LVEF) after revascularization. BACKGROUND FDG SPECT has recently been proposed for assessment of myocardial viability. However, FDG SPECT still awaits validation in terms of predicting improvement of contractile function after revascularization in patients with poor left ventricular (LV) function. METHODS Fifty-five patients with contractile dysfunction (including 22 with LVEF < 30%) underwent FDG SPECT during hyperinsulinemic glucose clamping and early thallium-201 SPECT (to assess perfusion). Improvement of LV function was evaluated 3 months after revascularization with echocardiography and radionuclide ventriculography. RESULTS The 55 patients were arbitrarily classified into two groups: 19 with three or more viable, dysfunctional segments on FDG SPECT and 36 with less than three viable, dysfunctional segments. LVEF increased significantly in the first group, from 28 +/- 8% (mean +/- SD) before to 35 +/- 9% (p < 0.01) after revascularization. In the second group, LVEF remained unchanged after revascularization (45 +/- 14% vs. 44 +/- 14%, p = NS). The 22 patients with severely depressed LV function were similarly classified into two groups: 14 with three or more viable segments on FDG SPECT in whom LVEF improved significantly (25 +/- 6% vs. 32 +/- 6%) and 8 with less than three viable segments in whom LVEF remained unchanged (24 +/- 6% vs. 25 +/- 6%). CONCLUSIONS This study shows that FDG SPECT can identify patients in whom LV function improves after revascularization. Because SPECT is widely available, this technique may contribute to more routine use of FDG for determination of viability.

Laparoscopic detection of sentinel lymph nodes followed by lymph node dissection in patients with early stage cervical cancer.

OBJECTIVE The purpose of this study was to investigate the feasibility of sentinel node detection through laparoscopy in patients with early cervical cancer. Furthermore, the results of laparoscopic pelvic lymph node dissection were studied, validated by subsequent laparotomy. METHODS Twenty-five patients with early stage cervical cancer who planned to undergo a radical hysterectomy and pelvic lymph node dissection received an intracervical injection of technetium-99m colloidal albumin as well as blue dye. With a laparoscopic gamma probe and with visual detection of blue nodes, the sentinel nodes were identified and separately removed via laparoscopy. If frozen sections of the sentinel nodes were negative, a laparoscopic pelvic lymph node dissection, followed by radical hysterectomy via laparotomy, was performed. If the sentinel nodes showed malignant cells on frozen section, only a laparoscopic lymph node dissection was performed. RESULTS One or more sentinel nodes could be detected via laparoscopy in 25/25 patients (100%). A sentinel node was found bilaterally in 22/25 patients (88%). Histological positive nodes were detected in 10/25 patients (40%). One patient (11%) had two false negative sentinel nodes in the obturator fossa, whereas a positive lymph node was found in the parametrium removed together with the primary tumor. In seven patients (28%), the planned laparotomy and radical hysterectomy were abandoned because of a positive sentinel node. Bulky lymph nodes were removed through laparotomy in one patient, and in six patients only laparoscopic lymph node dissection and transposition of the ovaries were performed. These patients were treated with chemoradiation. In two patients, a micrometastasis in the sentinel node was demonstrated after surgery. Ninety-two percent of all lymph nodes was retrieved via laparoscopy, confirmed by laparotomy. Detection and removal of the sentinel nodes took 55 +/- 17 min. Together with the complete pelvic lymph node dissection, the procedure lasted 200 +/- 53 min. CONCLUSION Laparoscopic removal of sentinel nodes in cervical cancer is a feasible technique. If radical hysterectomy is aborted in the case of positive lymph nodes, sentinel node detection via laparoscopy, followed by laparoscopic lymph node dissection, prevents potentially harmful and unnecessary surgery.

Performance characteristics of a 511-keV collimator for imaging positron emitters with a standard gamma-camera

Line-source experiments were conducted to assess the performance of a gamma-camera equipped with a specially designed 511-keV collimator for the planar imaging of positron emitters. The results were compared with the camera performance with routinely used collimators and radionuclides (thallium-201, technetium-99m and gallium-67). With positron emitters, scatter contributed less to the widening of the line spread function than with radionuclides emitting lower photon energies. These observations can be explained by the relative deterioration in the discrimination power of the gamma-camera to reject scattered radiation at low energies. Planar 511-keV imaging may provide relevant clinical information, as we showed by fluorodeoxyglucose studies in a patient with a myocardial infarction and in a patient with a malignant lymphoma. It is concluded that positron emitters can be effectively applied for planar imaging with the generally available gamma-cameras. This study implies that radiotracers developed for positron emission tomography may find a place in the practice of conventional nuclear medicine.

Ultrasound measurements in the calcaneus: precision and its relation with bone mineral density of the heel, hip, and lumbar spine.

Broadband ultrasound attenuation (BUA) and speed of sound (SOS) in the heel are suggested to measure bone density and structure and to predict fracture risk. Short-term precision (five consecutive measurements in 1 h) and long-term precision (six within 3 months) of ultrasound parameters were studied in 20 healthy subjects. The coefficient of variation (CV) did not change over a 3-month period for SOS (1.3%). Short-term precision of BUA was 3.4% (CV) and long-term precision was 4.9% (CV) (not significantly different: p = 0.09). Relationships between ultrasound parameters and BMD at various sites were examined in 42 subjects. BMD at the heel was assessed at the location corresponding to that of the ultrasound measurements (BMDheel). Correlation coefficients, corrected for imprecision in the measurements, for BUA and SOS vs. BMDheel, were 0.81 and 0.76, respectively. The correlation coefficients between heel measurements (BUA, SOS, and BMDheel) and BMD in the hip and lumbar spine ranged from 0.37 to 0.57. The relationships between BUA, SOS, and BMDheel vs. BMD of the hip were modified by physical activity and body weight. Higher physical activity and body weight were associated with higher BMD values at the hip. BUA values < 60 dB/MHz predicted BMD at the femoral neck < 0.70 g/cm2 with a sensitivity and specificity of 80% and 93%, respectively. After the age of 30, 11 participants had sustained vertebral fractures and 12 participants nonvertebral osteoporotic fractures. BUA and SOS values were significantly lower in fracture patients than in participants without fractures. It can be concluded that ultrasound measurements at the heel correlate well to BMD at the same site. BUA can predict BMD at the hip and is lower when the subject has sustained fractures.

Plasma protein levels are markers of pulmonary vascular permeability and degree of lung injury in critically ill patients with or at risk for acute lung injury/acute respiratory distress syndrome*

Objectives:To evaluate the diagnostic value of plasma protein levels for pulmonary vascular permeability and acute respiratory distress syndrome. During acute lung injury and acute respiratory distress syndrome, increased vascular permeability induces protein-rich fluid extravasation. We hypothesized that plasma protein levels predict increased vascular permeability and acute respiratory distress syndrome. Design:A prospective, observational study. Patients:Eighty-three consecutive, mechanically ventilated patients with or at risk for acute lung injury/acute respiratory distress syndrome, of whom 18 had sepsis. Patients with increased pulmonary capillary wedge pressures or central venous pressures were excluded. Interventions:Patients were subjected to pulmonary capillary wedge pressure/central venous pressure-guided fluid loading with saline or colloid fluids. Measurements and Main Results:We measured plasma albumin and transferrin levels and determined the 67Gallium-transferrin pulmonary leak index, the American European Consensus Conference criteria, and the lung injury score. Measurements were performed before and after fluid loading to evaluate effects of fluid loading. Plasma albumin and transferrin levels were approximately 30% lower in acute respiratory distress syndrome than patients with acute lung injury (p < .01) and patients without lung injury (p < .05). Protein levels inversely related to the pulmonary leak index (standardized regression coefficient −0.28, p < .001 for albumin; standardized regression coefficient −0.30, p = .003 for transferrin) and the lung injury score (standardized regression coefficient −0.19, p = .01 for albumin), independently of presence of sepsis, severity of disease, and fluid loading. Albumin and transferrin levels had a high sensitivity (77–93%) and negative predictive value (80–98%) for elevated pulmonary vascular permeability and acute respiratory distress syndrome (American European Consensus Conference criteria and lung injury score). The addition of hypoalbuminemia (<17.5 g/L) and hypotransferrinemia (<0.98 g/L) as criteria to the American European Consensus Conference criteria or the lung injury score increased their predictive values for elevated pulmonary vascular permeability. Conclusions:In critically ill patients, decreased plasma albumin and transferrin levels parallel increased pulmonary vascular permeability irrespective of underlying disease and fluid status. While normal levels help to exclude acute respiratory distress syndrome, hypoalbuminemia and hypotransferrinemia increase the diagnostic accuracy of the American European Consensus Conference criteria and lung injury score for elevated pulmonary vascular permeability.

Resorbable calcium phosphate particles as a carrier material for bone marrow in an ovine segmental defect

Resorbable calcium phosphate ceramics are only osteoconductive; therefore, their combination with osteogenic substances may lead to stimulation of bone healing. In the present study this combination, using autologous bone marrow, was investigated. In 31 sheep, a 3-cm tibial segmental defect was created and stabilized with an intramedullary nail. The animals were divided into four groups: empty defects (group 1, n = 7), and defects filled with 10-mL dense resorbable calcium phosphate particles (group 2, n = 8), with 10-mL particles soaked in bone marrow (group 3, n = 8), or with 10-mL autologous bone (group 4, n = 8). On evaluation after 12 weeks, significantly higher values were seen in group 3 than in group 2 for callus volume (p = .016), bone mineral density ratio (p = .03), bone mineral content ratio (p = .04), torsional strength (p = .005), and torsional stiffness (p = .01). For all end points, the outcome of group 3 was lower than that of group 4. In the histology, there was direct contact between newly formed bone and remnants of the particles. There were no signs of inflammatory reactions. Although a stimulatory effect of bone marrow was seen, the combination of resorbable calcium phosphate particles with bone marrow does not provide an alternative for autologous bone grafting.

Predictive Value of Planar 1 8F-Fluorodeoxyglucose Imaging for Cardiac Events in Patients After Acute Myocardial Infarction

This long-term study examines the predictive value of planar myocardial 18F-fluorodeoxyglucose (FDG) imaging for cardiac events after acute myocardial infarction (AMI). From December 1989 to April 1991, 59 consecutive patients with AMI had undergone planar rest thallium-201 (Tl-201)/FDG imaging for viability assessment; 53 (42 men) were included in this study. Mean follow-up was 47 +/- 15 months. Cardiac events were defined as cardiac-related death, reinfarction, late revascularization, and unstable angina pectoris. A mismatch pattern was defined as a FDG uptake exceeding Tl-201 uptake by > or = 20%. A concordant reduction in flow and metabolism was defined as a match. In the mismatch group (n = 39) were 19 events versus 1 event in the match group (n = 14) (p <0.009). In the mismatch group were 5 cardiac deaths, 3 reinfarctions, 7 late revascularizations, and 4 patients had unstable angina pectoris. There was 1 cardiac death in the match group. The event-free rate estimated using Kaplan Meier curves for patients with and without a mismatch was significantly different (p = 0.018). The relative risk for patients with a mismatch for developing a future cardiac event was estimated at 7.8 versus patients with a match. Thus, planar myocardial FDG imaging shortly after AMI has important prognostic significance for prediction of future cardiac events. Patients with a mismatch shortly after AMI have a high risk for future cardiac events on medical therapy.

Early response monitoring in malignant lymphoma using fluorine-18 fluorodeoxyglucose single-photon emission tomography.

Metabolic response monitoring early during chemotherapy may have a major impact on clinical management of patients with malignant lymphoma. In two patients with non-Hodgkins lymphoma fluorine-18 fluorodeoxyglucose (IgFDG) single-photon emission tomography (SPET) studies were performed during the first two chemotherapeutic cycles. Persisting uptake predicted treatment failure whereas a sharp reduction of 18FDG uptake was demonstrated in the case of a responsive tumour. Qualitative analysis of conventional 18FDG imaging may thus serve to identify patients with a non-responding tumour. The potential of this technique in the determination of the initial response remains to be established. Imaging with 18FDG and SPET appears promising as a more easily available methodology than 18FDG positron emission tomography.

Comparison of Coronary CT Angiography, SPECT, PET, and Hybrid Imaging for Diagnosis of Ischemic Heart Disease Determined by Fractional Flow Reserve

Importance At present, the choice of noninvasive testing for a diagnosis of significant coronary artery disease (CAD) is ambiguous, but nuclear myocardial perfusion imaging with single-photon emission tomography (SPECT) or positron emission tomography (PET) and coronary computed tomography angiography (CCTA) is predominantly used for this purpose. However, to date, prospective head-to-head studies are lacking regarding the diagnostic accuracy of these imaging modalities. Furthermore, the combination of anatomical and functional assessments configuring a hybrid approach may yield improved accuracy. Objectives To establish the diagnostic accuracy of CCTA, SPECT, and PET and explore the incremental value of hybrid imaging compared with fractional flow reserve. Design, Setting, and Participants A prospective clinical study involving 208 patients with suspected CAD who underwent CCTA, technetium 99m/tetrofosmin–labeled SPECT, and [15O]H2O PET with examination of all coronary arteries by fractional flow reserve was performed from January 23, 2012, to October 25, 2014. Scans were interpreted by core laboratories on an intention-to-diagnose basis. Hybrid images were generated in case of abnormal noninvasive anatomical or functional test results. Main Outcomes and Measures Hemodynamically significant stenosis in at least 1 coronary artery as indicated by a fractional flow reserve of 0.80 or less and relative diagnostic accuracy of SPECT, PET, and CCTA in detecting hemodynamically significant CAD. Results Of the 208 patients in the study (76 women and 132 men; mean [SD] age, 58 [9] years), 92 (44.2%) had significant CAD (fractional flow reserve ⩽0.80). Sensitivity was 90% (95% CI, 82%-95%) for CCTA, 57% (95% CI, 46%-67%) for SPECT, and 87% (95% CI, 78%-93%) for PET, whereas specificity was 60% (95% CI, 51%-69%) for CCTA, 94% (95% CI, 88%-98%) for SPECT, and 84% (95% CI, 75%-89%) for PET. Single-photon emission tomography was found to be noninferior to PET in terms of specificity (P < .001) but not in terms of sensitivity (P > .99) using the predefined absolute margin of 10%. Diagnostic accuracy was highest for PET (85%; 95% CI, 80%-90%) compared with that of CCTA (74%; 95% CI, 67%-79%; P = .003) and SPECT (77%; 95% CI, 71%-83%; P = .02). Diagnostic accuracy was not enhanced by either hybrid SPECT and CCTA (76%; 95% CI, 70%-82%; P = .75) or by PET and CCTA (84%; 95% CI, 79%-89%; P = .82), but resulted in an increase in specificity (P = .004) at the cost of a decrease in sensitivity (P = .001). Conclusions and Relevance This controlled clinical head-to-head comparative study revealed PET to exhibit the highest accuracy for diagnosis of myocardial ischemia. Furthermore, a combined anatomical and functional assessment does not add incremental diagnostic value but guides clinical decision-making in an unsalutary fashion.