Background In patients with coronary artery disease, dysfunctional hypoperfused myocardium at rest may represent either necrotic or viable hibernating myocardium. The accuracy of inotropic stimulation in identifying hypoperfused, reversibly dysfunctional myocardium has not been extensively investigated. Methods and Results Eighteen patients with stable chronic coronary artery disease underwent, while off drugs, quantitative ²⁰¹ Tl single-photon emission computed tomography after rest injection (2 to 3 mCi), two-dimensional echocardiography at rest and during dobutamine (5 to 10 μg/kg per minute IV), and radionuclide angiography. Single-photon emission computed tomography and echocardiography at rest were repeated 34±10 days after coronary revascularization, and radionuclide angiography was repeated 45±13 days after revascularization. Resting hypoperfusion was defined as ²⁰¹ Tl uptake 1 grade. Of 79 dysfunctional hypoperfused segments, 48 (61%) improved function after revascularization. In 42 (88%) of these latter segments, function had improved during dobutamine. Conversely, systolic function after revascularization did not improve in 31 segments, and in 27 (87%), it had not improved during dobutamine. Functional improvement after revascularization was observed in 42 (91%) of 46 segments manifesting an improvement during dobutamine as opposed to 6 (18%) of 33 segments that did not improve during dobutamine. Resting ²⁰¹ Tl uptake (% of maximal activity) before revascularization (65±9%) significantly increased at follow-up in segments where function improved (70±12%, P <.005), whereas it did not change significantly in segments with unchanged systolic function after revascularization (from 57±13% to 60±17%, P =NS). In 10 patients with prerevascularization ejection fraction <45%, left ventricular ejection fraction significantly increased from 36±7% before revascularization to 42±7% at follow-up ( P <.05). Conclusions Inotropic stimulation using dobutamine echocardiography identifies hypoperfused reversibly dysfunctional myocardium. Functional improvement during dobutamine is highly predictive of improvement after revascularization.

Background To date, late redistribution after resting ²⁰¹ Tl injection has not been evaluated. In addition, the concordance between resting ²⁰¹ Tl imaging and dobutamine echocardiography in identifying viable myocardium has not been assessed. Methods and Results Forty patients with coronary artery disease underwent rest–4-hour–24-hour ²⁰¹ Tl tomography and dobutamine echocardiography (5 to 10 μg·kg ⁻¹ ·min ⁻¹ ). Late redistribution occurred in 46 (21%) of 219 persistent defects at 4 hours. Systolic function and contractile reserve were similar among persistent defects at 4 hours with and without late redistribution. Contractile reserve was more frequent in segments with normal ²⁰¹ Tl uptake (59%), completely reversible defects (53%), or mild to moderate defects at 4 hours (56%) compared with severe defects (14%; P <.02 versus all). Of 105 hypokinetic segments, 99 (94%) were viable by ²⁰¹ Tl, and 88 (84%) showed contractile reserve. In contrast, of 155 akinetic segments, 119 (77%) were viable by ²⁰¹ Tl, but only 34 (22%) had contractile reserve. Concordance between ²⁰¹ Tl and dobutamine was 82% in hypokinetic segments but 43% in akinetic segments. In 109 revascularized segments, positive accuracy for functional recovery was 72% for ²⁰¹ Tl and 92% for dobutamine, whereas negative accuracy was 100% and 65%, respectively. Sensitivity was 100% for ²⁰¹ Tl and 79% for dobutamine. Conclusions Late redistribution occurs in one fifth of persistent defects at 4 hours, and it does not correlate to systolic function or contractile reserve. Dobutamine and ²⁰¹ Tl yield concordant information in the majority of hypokinetic segments, whereas concordance is low in akinetic segments. Dobutamine demonstrates higher positive accuracy and sensitivity in predicting recovery of dysfunctional myocardium, whereas ²⁰¹ Tl shows higher negative predictive accuracy but reduced positive accuracy.

¹⁸F-FDG PET/CT allows the direct measurement of metabolic tumor burden in a variety of different malignancies. The aim of this study was to assess whether metabolic tumor volume (MTV) determined by ¹⁸F-FDG PET/CT could be used in the prediction of progression-free and overall survival in multiple myeloma patients. Methods: Forty-seven patients (18 women, 29 men; mean age ± SD, 63 ± 11 y) with stage IIIA disease who had undergone whole-body ¹⁸F-FDG PET/CT were retrospectively evaluated. Images underwent a 3-dimensional region-of-interest analysis including all focal lesions with a maximum standardized uptake value > 2.5. The MTV of each lesion was calculated using an automated contouring program based on the standardized uptake value and developed with a threshold of 40% of the maximum standardized uptake value. The total MTV of each patient was defined as the sum of metabolic volume of all focal lesions. Patients were treated and then subjected to a mean follow-up period of 24 mo. Results: In the 47 patients studied, MTV range was 1.3–316.3 mL, with a median of 23.7 mL. A direct, significant correlation was found between MTV and the percentage of diffuse infiltration of bone marrow by plasma cells (r = 0.46, P = 0.006), whereas hemoglobin levels were inversely correlated with MTV (r = −0.56, P = 0.0001). At follow-up, patients who developed progressive disease (n = 18) showed a significantly higher MTV (74.7 ± 19.3 vs. 29.8 ± 5.1 mL, P = 0.009) than patients without progressive disease (n = 29). Furthermore, patients who died of myeloma (n = 9) had a significantly higher MTV (123.2 ± 30.6 vs. 28.9 ± 4.2 mL, P = 0.0001) than survivors (n = 38). No differences in age, plasma cell infiltration, M protein, albumin, β2-microglobulin, performance status, International Staging System score, and presence or absence of a bone marrow transplant were found between groups. The MTV cutoff level was determined by receiver-operating-characteristic curve analysis, and the best discriminative value found for predicting progression-free and overall survival was 42.2 and 77.6 mL, respectively. By Kaplan–Meier analysis and log-rank testing, progression-free and overall survival at follow-up were significantly better in patients showing an MTV lower than the cutoff than in those having an MTV higher than the cutoff (χ² = 3.9, P = 0.04, and χ² = 56.3, P < 0.0001, respectively). Conclusion: The direct measurement of tumor burden obtained by calculating MTV on ¹⁸F-FDG PET/CT images may be used in the prediction of progression-free and overall survival in myeloma patients.

New imaging techniques have been introduced to assess the extent and severity of disease in multiple myeloma (MM) patients. The aim of our study was to compare newer imaging modalities-such as (18)F-FDG PET/CT, (99m)Tc-methoxyisobutylisonitrile ((99m)Tc-MIBI) scintigraphy, and MRI-to assess their relative contribution in the evaluation of MM patients at diagnosis. Thirty-three newly diagnosed patients with MM were prospectively studied. Diagnosis and staging were made according to standard criteria. All patients underwent whole-body (18)F-FDG PET/CT, whole-body (99m)Tc-MIBI, and MRI of the spine and pelvis within 10 d, and imaging findings were compared. (18)F-FDG PET/CT was positive in 32 patients (16 focal uptake, 3 diffuse uptake, 13 focal and diffuse uptake), (99m)Tc-MIBI was positive in 30 patients (6 focal, 11 diffuse, 13 focal and diffuse uptake), and MRI of the spine and pelvis was positive in 27 patients (6 focal, 13 diffuse, 8 focal and diffuse uptake). (18)F-FDG PET/CT showed a total of 196 focal lesions (178 in bones and 18 in soft tissues), of which 121 were in districts other than the spine and pelvis, whereas (99m)Tc-MIBI visualized 63 focal lesions (60 in bones and 3 in soft tissues), of which 53 were in districts other than the spine and pelvis. In the spinal and pelvic regions, (18)F-FDG PET/CT detected 75 focal lesions (35 in spine and 40 in pelvis), (99m)Tc-MIBI visualized 10 focal lesions (1 in spine and 9 in pelvis), and MRI detected 51 focal lesions (40 in spine and 11 in pelvis). In whole-body analysis, (18)F-FDG PET/CT performed better than (99m)Tc-MIBI in the detection of focal lesions, whereas (99m)Tc-MIBI was superior in the visualization of diffuse disease. In the spine and pelvis, MRI was comparable to (18)F-FDG PET/CT and (99m)Tc-MIBI in the detection of focal and diffuse disease, respectively. Because myelomatous lesions may often occur out of spinal and pelvic regions, MRI should be reserved to the evaluation of bone marrow involvement of these districts, whereas (18)F-FDG PET/CT can significantly contribute to an accurate whole-body evaluation of MM patients. Finally, whole-body (99m)Tc-MIBI, despite its limited capacity in detecting focal lesions, may be an alternative option when a PET facility is not available.