[111 INDIUM LABELED LEUKOCYTE SCINTIGRAPHY IS A LOW SENSITIVITY TEST FOR DIAGNOSING PROSTHETIC JOINT INFECTION IN EQUIVOCAL CASES].

INTRODUCTION: Nuclear medicine techniques are suggested to be used in equivocal cases only. Nuclear medicine procedures, specifically labeled leucocytes however, are widely used in the diagnosis of joint infection across Europe. The aim of our study was to determine if Indium 111 labeled leukocyte scintigraphy has a role in the diagnosis of infected prosthetic joints. METHODS: In this retrospective cohort study, the records of a total of 146 prosthetic hip or knee revision surgeries, in 116 patients, performed in our Institute between the years 2013-2016 were reviewed. A total of 34 patients with labeled leukocyte scans were analyzed. Ten patients had more than one scan (two to four times). The scintigraphy result reports were correlated with the outcome with respect to intra-/post-operative diagnosis of prosthetic joint infection. RESULTS: The findings of 42 of 44 scintigraphy tests were negative. One study in a patient who had three prior negative labeled white blood cells (WBC) scintigraphies was equivocal. One study was positive, but a later test in the same patient was negative. Of these 34 patients, nine were demonstrated intra- or post operatively as positive for infected prosthetic joint, including the two positive cases above. The remaining 25 patients went through revision surgery with no evidence of infection; 30 of 38 bone scans were positive. Of these 30 patients, seven were demonstrated intra- or post-operatively as positive for infected prosthetic joint. CONCLUSIONS: In our study population indium labeled leukocyte scintigraphy was found to be a non-sensitive test for the diagnosis of a prosthetic joint infection and had a poor negative predictive value. It is expected that following the guidelines more strictly and choosing the appropriate modality for assessing prosthetic joint infection will improve the diagnostic accuracy of these techniques.

Two decades of SPECT/CT - the coming of age of a technology: An updated review of literature evidence.

PURPOSE: Single-photon emission computed tomography (SPECT) combined with computed tomography (CT) was introduced as a hybrid SPECT/CT imaging modality two decades ago. The main advantage of SPECT/CT is the increased specificity achieved through a more precise localization and characterization of functional findings. The improved diagnostic accuracy is also associated with greater diagnostic confidence and better inter-specialty communication. METHODS: This review presents a critical assessment of the relevant literature published so far on the role of SPECT/CT in a variety of clinical conditions. It also includes an update on the established evidence demonstrating both the advantages and limitations of this modality. CONCLUSIONS: For the majority of applications, SPECT/CT should be a routine imaging technique, fully integrated into the clinical decision-making process, including oncology, endocrinology, orthopaedics, paediatrics, and cardiology. Large-scale prospective studies are lacking, however, on the use of SPECT/CT in certain clinical domains such as neurology and lung disorders. The review also presents data on the complementary role of SPECT/CT with other imaging modalities and a comparative analysis, where available.

Strategies for Minimizing Occupational Radiation Exposure in Cardiac Imaging.

PURPOSE OF REVIEW: Radiation safety has been at the center of interest of both researchers and healthcare institutions. This review will summarize and shed light on the various techniques adapted to reduce staff exposure to ionizing radiation (IR) in the field of cardiac imaging. RECENT FINDINGS: In the last years, with the advance of awareness and the development of new technologies, there have been several tools and techniques adapted. The breakthrough of several technologies to lower radiation dose and shorten the duration of diagnostic tests associated with IR, the use of protection devices by staff members, and mostly the awareness of exposure to IR are the hallmark of these advances. Using all these measures has led to a significant decrease in staff exposure to IR. Reducing staff exposure to meet the "As Low As Reasonably Achievable" principle is feasible. This review introduces the most important strategies applied in cardiac imaging.

68Ga-PSMA PET/CT in prostate cancer patients - patterns of disease, benign findings and pitfalls.

BACKGROUND: 68Ga-PSMA PET/CT has an important role in assessment of prostate cancer patients with biochemical recurrence and is evolving in staging high- and intermediate risk disease. The aim of present study was to describe the metastatic patterns and frequency of involved sites of prostate cancer and to assess the incidence of benign Ga68-PSMA avid PET/CT findings in a large patient population. METHODS: 68Ga-PSMA PET/CT studies performed in two tertiary medical centers over a period of 24 months were retrospectively reviewed. The incidence and location of pathological 68Ga-PSMA avid foci, suspicious to represent malignancy, as well as those of unexpected benign foci of increased 68Ga-PSMA activity were documented and analyzed. RESULTS: There were 445 68Ga-PSMA studies in 438 men (mean age 72.4, range 51-92 years) with prostate cancer referred for biochemical failure (n = 270, 61%), staging high-risk disease (n = 112, 25%), response assessment (n = 30, 7%), follow-up (n = 22, 5%) and suspected bone metastases (n = 11, 2%). 68Ga-PSMA avid disease sites were observed in 319 studies (72%), in 181 studies (67%) for biochemical recurrence, 94 studies for staging (84%) (p < 0.05), in 22 studies for response assessment (73%), 10 follow up studies (45%) and in five patients with suspected bone metastases (45%). 68Ga-PSMA avid lesions were most commonly detected in the prostate (n = 193, 43%), loco-regional spread (n = 51, 11%), abdomino-pelvic nodes (n = 129, 29%) and distant metastases (n = 158, 36%), including bone metastases (n = 11, 25%), distant lymphadenopathy (n = 29, 7%) and other organs (n = 18, 4%). Distant 68Ga-PSMA-avid metastases were commonly seen in patients with biochemical recurrence (14/21 lesions), but were not seen in patient referred for staging (p < 0.013). There were 96 non-malignant 68Ga-PSMA avid foci in 81 studies, most common in reactive lymph nodes (n = 36, 38%), nonmalignant bone lesions (n = 21, 22%), thyroid nodules (n = 9, 9%), ganglions (n = 9, 9%) and lung findings (n = 8, 8%). CONCLUSION: The distribution of 68Ga-PSMA avid metastatic lesions is similar to data previously reported mainly from autopsy with comparable detection rates, indicating 68Ga-PSMA PET/CT is an accurate detection tool in patients with metastatic prostate cancer. If confirmed by further prospective studies 68Ga-PSMA PET/CT should be included in the guidelines to evaluate disease extent in these patients.

Evaluation of Staff Radiation Exposure during Transthoracic Echocardiography Close to Myocardial Perfusion Imaging.

BACKGROUND: Transthoracic echocardiography (TTE) and myocardial perfusion imaging (MPI) are used in cardiac patients. In this study the radiation exposure of sonographers performing TTE following MPI was evaluated. METHODS: Of 40 study patients, 30 underwent same-day 99mTc sestamibi MPI and TTE, while another 10 underwent only TTE. Patients who underwent both studies were divided into three groups: right-handed TTE performed by an echocardiographer and right- and left-handed TTE performed by a cardiac sonographer. Seven thermoluminescent radiation dosimeter badges monitored the forehead, wrists, anterolateral right and left chest, sternal notch, and umbilical region of each examiner. Group characteristics were compared. Radiation exposures were deemed positive if >0.1 mSv. RESULTS: There were no statistical differences in patient weight and body mass index. The left-handed approach group had higher residual radioactivity (979 ± 73 vs 884 ± 73 MBq [P < .01] and 906 ± 81 MBq [P < .04]), but no statistical difference in duration of TTE, compared with the other two MPI groups. Radiation exposure was positive in the right anterolateral chest and hand (0.45 and 1 mSv, respectively) for the echocardiographer, the right anterolateral chest and wrist and umbilical region (0.59, 1.06, and 0.15 mSv, respectively) for the right-handed sonographer, and the left chest and hand (0.12 and 0.34 mSv, respectively) for the left-handed sonographer. Dosimeters indicated no radiation exposure in the TTE-only group. CONCLUSIONS: Staff members performing TTE after MPI are exposed to radiation that might warrant monitoring. Altering study sequence, adopting a left-handed approach, and using other radiation-reducing techniques can minimize the degree of exposure.

Preoperative [99mTc]MIBI SPECT/CT Interpretation Criteria for Localization of Parathyroid Adenomas-Correlation with Surgical Findings.

PURPOSE: Minimally invasive surgery for parathyroid adenomas (PTA) requires precise identification and localization of the diseased gland prior to exploration for optimal surgical planning. The Perrier classification allows for accurate, reproducible, and reliable description of PTA location and communication of clinically significant information to surgeons. The current study compares the Perrier localization of PTA on [99mTc]methoxyisobutylisonitrile ([99mTc]MIBI) single-photon emission computed tomography (SPECT)/X-ray computed tomography (CT) with the results of surgery. PROCEDURES: Eighty-eight patients (60 females), age 13-82 years, with primary hyperparathyroidism underwent [99mTc]MIBI SPECT/CT prior to surgery. Eight patients had parathyroid hyperplasia and underwent excision of 3.5 parathyroid glands, including five patients with a negative [99mTc]MIBI study and three patients with multiple foci of uptake, and were excluded from further analysis. Each PTA was localized to Perrier levels A-G. The surgeon located each PTA found on surgery using the same classification. PTA localization on SPECT/CT and at surgery was compared. RESULTS: Eighty patients with surgically confirmed PTA were analyzed. On [99mTc]MIBI SPECT/CT, 63 patients had a single and one patient had two PTAs for a total of 65 PTAs. At surgery, 85 PTAs were resected in 80 patients, including 75 patients with single and 5 with two PTAs. Twenty PTAs found on surgery were not detected on [99mTc]MIBI. The relatively lower weight of these 20 PTAs is probably the main reason for the false-negative results group. The same Perrier localization was determined on SPECT/CT and surgery in 52/65 PTAs (80 %). In the 13 incongruent cases, the PTAs were localized at different locations but on the same side of the thyroid gland. CONCLUSIONS: [99mTc]MIBI SPECT/CT accurately localized a PTA according to the Perrier classification in 80 % of cases. Reporting SPECT/CT results using anatomy-based PTA localization criteria accepted by surgeons can contribute significantly towards better interspecialty communication and will improve performance of minimally invasive surgical removal of PTAs.

Prospective comparison of whole-body bone SPECT and sodium 18F-fluoride PET in the detection of bone metastases from breast cancer.

OBJECTIVE: The superiority of sodium F-fluoride PET (F-PET)/computed tomography (CT) over planar and single field-of-view single-photon emission computed tomography (SPECT) bone scintigraphy with Tc-methylene diphosphonate in bone metastases detection has been established. The present study prospectively compares whole-body Tc-methylene diphosphonate SPECT (WB-SPECT) and F-PET performance indices for the detection of bone metastases in breast cancer. METHODS: A total of 41 pairs of studies in female breast cancer patients (average age 58 years, range 30-75) were included. Half-time WB-SPECT and F-PET/CT were performed at a 4-day average interval (range 0-36 days), with subsequent fusion of CT to WB-SPECT. Two readers independently interpreted the studies, with differences resolved by consensus. Composite gold standard included the CT component of the F-PET/CT study with follow-up CT, MRI, F-fluoro-deoxyglucose-PET/CT, and bone scans. RESULTS: On patient-based analysis, metastases were diagnosed in 21 patients, with 19 patients detected by WB-SPECT and 21 with F-PET, the latter being the only modality to detect a single metastasis in two patients. The sensitivity of WB-SPECT and F-PET was 90 and 100% (P=NS), and the specificity were 95 and 85%, respectively (P=NS). On lesion-based analysis, 284 total sites of increased uptake were found. WB-SPECT detected 171/284 (60%) and F-PET 268/284 (94%) lesions, with good interobserver agreement for WB-SPECT (κ=0.679) and excellent agreement for F-PET (κ=0.798). The final analysis classified 204 lesions as benign and 80 as metastases. WB-SPECT identified 121 benign and 50 malignant sites compared with 192 and 76, respectively, for F-PET. WB-SPECT and F-PET had a sensitivity of 63 vs. 95%, P-value of less than 0.001, and a specificity of 97 vs. 96% (P=NS), respectively, on lesion-based analysis. CONCLUSION: F-PET had higher sensitivity for the diagnosis of bone metastases from breast cancer compared with WB-SPECT, showing a statistically significant 32% increase on lesion-based analysis.

Metabolic assessment of Merkel cell carcinoma: the role of 18F-FDG PET/CT.

OBJECTIVES: Merkel cell carcinoma (MCC) is a rare aggressive skin tumor associated with a high mortality rate. The present study evaluated the role of fluorine-18 fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) in subsequent management of patients with MCC. METHODS: A total of 101 consecutive F-FDG PET/CT studies of 46 patients with MCC (28 men, 68±15.4 years) were retrospectively evaluated and the role in clinical care was documented. RESULTS: There were 40 positive studies (40%) in 28 patients (61%); of these, 33 studies (33%) in 27 patients (59%) showed metastatic disease. Fifty-two PET/CT studies (51%) in 23/46 (50%) patients were negative. Fifty-three studies (52%) were performed for staging or restaging in 41 patients, 29 scans (29%) were performed for routine follow-up in 10 patients, nine studies were carried out for suspected recurrent disease in eight patients, and 10 studies were carried out for assessment of response to therapy in seven patients. On the basis of PET/CT results, there was a change in disease stage in 12 studies in 12 patients (26%) and further change in the management of seven patients (15%). Overall, 2/29 routine follow-up studies were positive with further impact on management in one patient. CONCLUSION: F-FDG PET-CT altered the stage of one of four patients and changed the management of one of seven MCC patients. In the majority of patients, a negative F-FDG PET-CT study excluded active MCC with a high degree of confidence. PET-CT contributed toward patient management when performed for staging and restaging, monitoring response to treatment, and suspected recurrent disease, but not in the routine follow-up of asymptomatic patients with MCC.

Whole-body bone SPECT in breast cancer patients: the future bone scan protocol?

OBJECTIVE: The aim of the study was to compare the detectability rate of bone metastases in breast cancer patients using whole-body single-photon emission computed tomography (WB-SPECT) performed with a half-time acquisition algorithm with that of planar ± selected field-of-view SPECT [standard bone scintigraphy (BS)]. MATERIALS AND METHODS: Ninety-two consecutive breast cancer patients (age range 35-74 years) underwent planar BS followed by WB-SPECT (acquisition time 28 min). Clinical and imaging follow-up data from BS, 18F-FDG-PET/CT and CT were used as composite reference standards. Institutional review board approval was obtained. For a review of standard BS results, data from a selected SPECT field-of-view were extracted from the WB-SPECT when requested by the readers. Diagnostic confidence of interpretation criteria were defined using a five-point level-of-confidence grading scale of lesions. RESULTS: Bone metastases were diagnosed in 34 of 92 studies (37%). On patient-based analysis, the detectability rate of standard BS was 97% (33/34 patients) as compared with 100% for WB-SPECT (P=NS). On a lesion-based analysis, 268 foci were detected, including 124 metastases. Standard BS detected 195 lesions (73%; 99 metastases and 96 benign) and missed 73 lesions (25 metastases and 48 benign). WB-SPECT detected 266 lesions (99%; 124 metastases and 142 benign) and missed two benign foci because of SPECT reconstruction artefacts. The lesion-based detectability rate of metastases for standard BS was 80% compared with 100% for WB-SPECT (P<0.001). WB-SPECT was associated with a higher level of confidence compared with standard BS for both benign (P<0.01) and malignant lesions (P<0.05). CONCLUSION: WB-SPECT is a useful tool for skeletal assessment, showing good performance in comparison with standard BS in breast cancer patients, and may eliminate the need for an initial planar scan.

Added Value of SPECT/CT in the Evaluation of Benign Bone Diseases of the Appendicular Skeleton.

Bone scintigraphy is a sensitive technique to detect altered bone mineralization but has limited specificity. The use of SPECT/CT has improved significantly the diagnostic accuracy of bone scintigraphy, in patients with cancer as well as in evaluation of benign bone disease. It provides precise localization and characterization of tracer-avid foci, shortens the diagnostic workup, and decreases patient anxiety. Through both the SPECT and the CT components, SPECT/CT has an incremental value in characterizing benign bone lesions, specifically in the appendicular skeleton, as illustrated by present case series.

Metabolic PET/CT-guided lung lesion biopsies: impact on diagnostic accuracy and rate of sampling error.

UNLABELLED: CT-guided fine-needle aspiration (FNA) of lung lesions is subject to sampling errors. The current study assessed whether information provided by (18)F-FDG PET/CT will decrease the false-negative (FN) rate and thus improve the accuracy of CT-guided FNA. METHODS: Data from 311 consecutive patients with lung nodules who underwent (18)F-FDG PET/CT and CT-guided FNA within an interval of less than 30 d were retrospectively assessed. In-house-developed software was used to register CT images performed for the FNA procedure (CT FNA) with corresponding slices of the PET/CT study. The quality of registration was rated on a scale of 1 (excellent) to 5 (misregistration). Only cases scored 1 or 2 were further evaluated. The software provided the highest standardized uptake value (SUV) within the lesion and at the location of the tip of the aspirating needle. The distance between the tip and the area with the highest SUV within the lesion was measured. The mean distance from the tip of the needle to the focus with the highest SUV, as well as the mean difference between the maximum SUV in the whole lesion and at the needle tip, was calculated and compared for cases with true-positive (TP) and FN FNA results. Anatomic and metabolic parameters of lesions included in these 2 groups were also compared. RESULTS: There were 267 patients (86%) with score 1 or 2 registration quality for CT FNA and PET/CT/CT images, including 179 TP (67%), 5 false-positive (FP, 2%), 49 true-negative (TN, 18%), and 34 FN (13%) FNA results. The distance between the location of the needle tip and the focus with the highest SUV in the lesion was significantly greater in the FN group (15.4 ± 14 mm) than in the TP group (5.9 ± 13.4 mm, P < 0.001). The maximum SUV at the location of the aspirating needle tip was significantly higher in the TP group, at 6.4 ± 6.4, than in the FN group, at 4 ± 4.7 (P < 0.05). CONCLUSION: The present results demonstrate a relationship between the degree of metabolism at the site of tissue-sampling aspiration in lung lesions and the accuracy of FNA results. Anatomy- and metabolism-based FNA guidance using information provided by both (18)F-FDG PET and CT may improve the accuracy of histologic examinations, decrease the rate of FN results, and thus increase the probability of achieving a definitive diagnosis.

Neuroendocrine tumor imaging with 68Ga-DOTA-NOC: physiologic and benign variants.

OBJECTIVE: Imaging with (68)Ga-labeled 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-octreotide analogs has become an important modality in patients with neuroendocrine tumors (NETs). In addition to high uptake in NET lesions, prominent physiologic radiotracer activity has been reported in the pituitary gland, pancreas, adrenal glands, liver, and spleen, and faint activity has been reported in the thyroid and gastrointestinal tract. This article describes previously unknown sites of 68Ga-DOTA-1-NaI3-octreotide (NOC) uptake unrelated to NETs. MATERIALS AND METHODS: One hundred eighty-two patients (96 female and 86 male patients; age range, 4-89 years) with documented (n=156) or suspected (n=26) NETs underwent 207 68Ga-DOTA-NOC PET/CT studies. Studies were retrospectively reviewed for the presence, intensity, and localization of foci of increased uptake that were further correlated with findings on additional imaging studies and clinical follow-up for a period of 4-32 months. RESULTS: Uptake of 68Ga-DOTA-NOC not identified as NET or known physiologic activity was detected in 297 sites with confirmation in 149 of 207 studies (72%). The most common location of non-NET-related 68Ga-DOTA-NOC-avid sites was in small lymph nodes, followed by prostate, uterus, breasts, lungs, brown fat, musculoskeletal system, and other sites, including oropharynx, pineal body, thymus, aortic plaque, genitalia, surgical bed, and subcutaneous granuloma. Intensity of uptake in non-NET-related 68Ga-DOTA-NOC-avid sites ranged in maximum standardized uptake value from 0.8 to 10.5. CONCLUSION: Previously unreported benign sites of 68Ga-DOTA-NOC uptake were found in the majority of studies, suggesting the presence of somatostatin receptors in physiologic variants or processes with no evidence of tumor. Knowledge of increased tracer uptake in non-NET-related sites is important for accurate interpretation and for avoiding potential pitfalls of 68Ga-DOTA-NOC PET/CT.

Characterizing bone marrow involvement in Hodgkin's lymphoma by FDG-PET/CT.

PURPOSE: Fluoro-deoxyglucose positron emmission tomography combined with computed tomography (FDG-PET/CT) is superior to iliac bone marrow biopsy (iBMB) for detection of bone marrow involvement (BMI) in staging of Hodgkin's lymphoma (HL). The present study aims to characterize the patterns and distribution of BMI in HL as determined by FDG-PET/CT. METHODS: Reports of FDG-PET/CT studies performed for staging of HL were reviewed. BMI was defined as positive iBMB and/or foci of pathological FDG uptake in the skeleton that behaved in concordance with other sites of lymphoma in studies following chemotherapy. Number of FDG uptake foci, their specific location in the skeleton and the presence of corresponding lesions in the CT component of the study, and stage according to the Ann Arbor staging system, were recorded. RESULTS: The study included 473 patients. iBMB was performed in 336 patients. Nine patients had positive iBMB (9/336, 3%). Seventy-three patients (73/473, 15%) had FDG-PET/CT-defined BMI. The BM was the only extranodal site of HL in 52/473 patients (11 %). Forty-five patients had three or more foci of pathological skeletal FDG uptake (45/73, 62 %). Sixty-four patients (64/73, 88%) had at least one uptake focus in the pelvis or vertebrae. In 60 patients (60/73, 82%), the number of skeletal FDG uptake foci without corresponding CT lesions was equal to or higher than the number of foci with morphological abnormalities. CONCLUSION: FDG-PET/CT demonstrated BMI in 15% of patients with newly diagnosed HL. Diagnosis of BMI in HL by FDG-PET/CT was more sensitive than iBMB with potential upstage in 11% of patients. The most common pattern of FDG-PET/CT BMI was multifocal (at least three foci) skeletal FDG uptake, with at least one focus in the pelvis or vertebrae and no corresponding CT lesions.

18F-FDG uptake in noninfected prosthetic vascular grafts: incidence, patterns, and changes over time.

UNLABELLED: (18)F-FDG PET/CT is of value in the diagnosis of prosthetic vascular graft infection, but potential pitfalls related to tracer uptake in noninfected implants have been described. The current study assesses the incidence and patterns of (18)F-FDG uptake over time in noninfected grafts, in relationship to prosthetic material and location. METHODS: A 12-y PET/CT database was retrospectively searched for cancer patients with prosthetic vascular grafts. Data retrieved from patient files included graft location, material, and time from surgery. Images were reviewed by 2 nuclear medicine physicians in consensus, with the presence and patterns (focal, diffuse homogeneous, inhomogeneous) of increased (18)F-FDG uptake in grafts recorded. The mean standardized uptake value in grafts (SUV-G) and mediastinum (SUV-M) was measured. The ratio of SUV-G to SUV-M (SUV-G/SUV-M) was calculated for each graft. RESULTS: One hundred seven prostheses were identified in 102 studies in 43 cancer patients. Sixty-seven prostheses were made of Dacron, 33 of Gore-Tex, and 7 were native veins. No increased (18)F-FDG uptake was found in 9 grafts (native veins, 4; Gore-Tex, 3; Dacron, 2). There was diffuse homogeneous uptake in 68 and inhomogeneous uptake in 30 grafts. The homogeneous pattern was more prevalent in Gore-Tex whereas the inhomogeneous uptake was seen more in Dacron vascular grafts. None of the grafts demonstrated focal uptake. The SUV-G range was 0.4-6.3 (average, 1.9), and SUV-M range was 0.6-2.4 (average, 1.4). The intensity of uptake was significantly higher in Dacron (SUV-G = 2.35 and SUV-G/SUV-M = 1.72) than in Gore-Tex (SUV-G = 1.09, SUV-G/SUV-M = 0.91) and native vein grafts (SUV-G = 1.07, SUV-G/SUV-M = 0.75) (P < 0.005). Native vein grafts showed a significant decrease in (18)F-FDG uptake over time whereas synthetic grafts showed no change in intensity for a follow-up of up to 16 y. CONCLUSION: Diffuse (18)F-FDG uptake was found in 92% of noninfected vascular prostheses, more in Dacron grafts than with other materials. The intensity of (18)F-FDG uptake of synthetic grafts did not change over time. With knowledge of the presence, patterns, and persistence of (18)F-FDG uptake in noninfected vascular prostheses, misinterpretation of PET/CT studies in patients referred for suspected prosthetic infection and in those assessed for diseases unrelated to their graft status can be avoided.

Left ventricular function and functional recovery early and late after myocardial infarction: a prospective pilot study comparing two-dimensional strain, conventional echocardiography, and radionuclide myocardial perfusion imaging.

BACKGROUND: Visual left ventricular (LV) wall motion scoring is well established for the assessment of LV function, yet it is subjective, circumstantial, and relative and requires long training. Quantification of myocardial shortening (strain) using two-dimensional speckle-tracking is potentially less subjective. In this study, quantifiable LV contraction (two-dimensional strain) was prospectively cross-related with wall motion score (WMS) and radionuclide myocardial perfusion imaging (MPI) score in 20 patients (mean age, 54 ± 9 years) with acute myocardial infarctions, early and late after percutaneous revascularization. METHODS: Echocardiography and rest MPI were performed 3 to 5 days after acute myocardial infarction. Echocardiography was repeated at 4 months. Peak segmental and global endocardial longitudinal strain (LS) and circumferential strain (CS) were measured, and principal strain was calculated. Volumes, WMS, MPI scores, and strain were assessed independently. RESULTS: Two-dimensional strain, visual WMS, and radionuclide MPI score correlated closely. Strain thresholds for abnormal WMS were 11.7% for early LS, 18.2% for early CS, 13.9% for late LS, and 19.1% for late CS. Late principal strain correlated better with WMS and MPI score than either LS or CS. CS varied minimally over time, while LS improved in most segments. Higher early CS (>15%) was predictive of segmental functional recovery. MPI score correlated better with late rather than early strain, probably because early resting perfusion defects represent permanent damage. CONCLUSIONS: In this pilot study, strain correlated with echocardiographic WMS and the extent of ischemia (MPI score) early and late after revascularization in patients with acute myocardial infarction. Longitudinal and circumferential strain uncoupling was observed. LS appeared to be more sensitive to acute ischemia, whereas CS correlated better with improvement after revascularization.

Tumor aggressiveness and patient outcome in cancer of the pancreas assessed by dynamic 18F-FDG PET/CT.

UNLABELLED: This study aimed to assess the role of a quantitative dynamic PET model in pancreatic cancer as a potential index of tumor aggressiveness and predictor of survival. METHODS: Seventy-one patients with (18)F-FDG-avid adenocarcinoma of the pancreas before treatment were recruited, including 27 with localized tumors (11 underwent pancreatectomy, and 16 had localized nonresectable tumors) and 44 with metastatic disease. Dynamic (18)F-FDG PET images were acquired over a 60-min period, followed by a whole-body PET/CT study. Quantitative data measurements were based on a 2-compartment model, and the following variables were calculated: VB (fractional blood volume in target area), K(1) and k(2) (kinetic membrane transport parameters), k(3) and k(4) (intracellular (18)F-FDG phosphorylation and dephosphorylation parameters, respectively), and (18)F-FDG INF (global (18)F-FDG influx). RESULTS: The single significant variable for overall survival (OS) in patients with localized disease was (18)F-FDG INF. Patients with a high (18)F-FDG INF (>0.033 min(-1)) had a median OS of 6 and 5 mo for nonresectable and resected tumors, respectively, versus 15 and 19 mo for a low (18)F-FDG INF in nonresectable and resected tumors, respectively (P < 0.04). In metastatic disease, multivariate analysis found VB, K(1), and k(3) to be significant variables for OS (P < 0.043, <0.031, and <0.009, respectively). Prognostic factors for OS in the entire group of patients that were significant at multivariate analysis were stage of disease, VB, K(1), and (18)F-FDG INF (P < 0.00035, <0.03, <0.024, and <0.008, respectively). Median OS for all patients with a high (18)F-FDG INF, low VB, and high K(1) was 3 mo, as opposed to 14 mo in patients with a low (18)F-FDG INF, high VB, and low K(1) (P < 0.021), irrespective of stage and resectability. CONCLUSION: Quantitative (18)F-FDG kinetic parameters measured by dynamic PET in newly diagnosed pancreatic cancer correlated with the aggressiveness of disease. The (18)F-FDG INF was the single most significant variable for OS in patients with localized disease, whether resectable or not.

Early interim FDG PET/CT prediction of treatment response and prognosis in pediatric Hodgkin disease-added value of low-dose CT.

BACKGROUND: Interim 18F-FDG PET helps predict outcome and tailor treatment in adults with Hodgkin disease (HD). OBJECTIVE: The purpose of this study was to assess predictive values of interim 18F-FDG PET/CT in children with HD and to define the potential added value to interim PET of low-dose CT. MATERIALS AND METHODS: Children were prospectively enrolled August 2002-April 2007. PET/low-dose CT was performed at staging, after 2 cycles, at the end of treatment and during follow-up (mean 45 months). Treatment was unchanged regardless of interim results. PET and low-dose CT were read independently. RESULTS: Of 34 enrolled children (ages 3-17 years), 27 achieved complete response, 4 had progressive disease and 3 had relapse. Interim PET alone had positive and negative predictive values of 67% and 89%, respectively. Interim low-dose CT alone had positive and negative predictive values of 35% and 100%, respectively. Interim PET/CT had positive and negative predictive values of 75% and 96%, respectively. CONCLUSIONS: Early interim PET/CT was a good predictor of outcome. Integrated PET and low-dose CT improved the predictive value in children with HD.

Do hyperglycemia and diabetes affect the incidence of false-negative 18F-FDG PET/CT studies in patients evaluated for infection or inflammation and cancer? A Comparative analysis.

UNLABELLED: Diabetes mellitus (DM) is a common metabolic disorder. Hyperglycemia occurs in a significant proportion of patients with uncontrolled DM but can also be found in patients without diabetes. Although the relationship between (18)F-FDG uptake in malignant tumors and blood glucose levels has been previously addressed, it has not been investigated in cases of infection and inflammation, despite the high incidence of these entities in diabetic patients. The current study assessed whether hyperglycemia and DM affect the detectability rate of disease in (18)F-FDG PET/CT studies performed for patients with suspected infectious and inflammatory processes, as compared with a group of patients with malignant tumors. METHODS: (18)F-FDG PET/CT studies of 123 consecutive patients investigated for suspected infection or inflammation and 320 patients evaluated for malignancy were retrospectively analyzed. The presence of DM and the level of glucose at the time of the study were recorded. Differences between the 2 study populations in false-negative (FN) rates in patients with and without hyperglycemia and DM were compared and analyzed for statistical significance. RESULTS: In the infection or inflammation group, 19 of 123 patients (15%) had serum glucose levels greater than 180 mg/dL and 43 of 123 (35%) had DM. There were no FN studies in patients with hyperglycemia and 4 FN studies in patients with normal glucose levels. There were 2 FN studies each in patients with and without DM. Neither glucose levels nor DM affects the detection rate of infection or inflammation with (18)F-FDG PET/CT. In the oncology group, 84 of 320 patients (26%) had serum glucose levels greater than 180 mg/dL and 183 of 320 (57%) had DM. There were 6 FN studies in cancer patients with hyperglycemia and 7 in patients with normal glucose levels. There were 8 FN studies in cancer patients with DM and 5 FN studies in patients without DM. Higher glucose levels but not DM affected the detection rate of malignancy with (18)F-FDG PET/CT. CONCLUSION: High glucose levels at the time of the study but not DM may reduce the sensitivity of (18)F-FDG PET/CT in the assessment of malignancy. No significant impact on the FN rate was found in patients with infection and inflammatory processes with either DM or hyperglycemia.

A review on the clinical uses of SPECT/CT.

In the era when positron emission tomography (PET) seems to constitute the most advanced application of nuclear medicine imaging, still the conventional procedure of single photon emission computed tomography (SPECT) is far from being obsolete, especially if combined with computed tomography (CT). In fact, this dual modality imaging technique (SPECT/CT) lends itself to a wide variety of useful diagnostic applications whose clinical impact is in most instances already well established, while the evidence is growing for newer applications. The increasing availability of new hybrid SPECT/CT devices with advanced technology offers the opportunity to shorten acquisition time and to provide accurate attenuation correction and fusion imaging. In this review we analyse and discuss the capabilities of SPECT/CT for improving sensitivity and specificity in the imaging of both oncological and non-oncological diseases. The main advantages of SPECT/CT are represented by better attenuation correction, increased specificity, and accurate depiction of the localization of disease and of possible involvement of adjacent tissues. Endocrine and neuroendocrine tumours are accurately localized and characterized by SPECT/CT, as also are solitary pulmonary nodules and lung cancers, brain tumours, lymphoma, prostate cancer, malignant and benign bone lesions, and infection. Furthermore, hybrid SPECT/CT imaging is especially suited to support the increasing applications of minimally invasive surgery, as well as to precisely define the diagnostic and prognostic profile of cardiovascular patients. Finally, the applications of SPECT/CT to other clinical disorders or malignant tumours is currently under extensive investigation, with encouraging results in terms of diagnostic accuracy.