177Lu-PSMA Therapy.

Radiopharmaceutical therapy using 177Lu-prostate-specific membrane antigen (PSMA) is an effective prostate cancer treatment that was recently approved by the U.S. Food and Drug Administration. This method leverages the success of PSMA-targeted PET imaging, enabling delivery of targeted radiopharmaceutical therapy; has demonstrated a clear benefit in large prospective clinical trials; and promises to become part of the standard armamentarium of treatment for patients with prostate cancer. This review highlights the evidence supporting the use of this agent, along with important areas under investigation. Practical information on technology aspects, dose administration, nursing, and the role of the treating physician is highlighted. Overall, 177Lu-PSMA treatment requires close collaboration among referring physicians, nuclear medicine technologists, radiopharmacists, and nurses to streamline patient care.

Intra-individual comparison of lymphatic drainage patterns using subareolar and peritumoral isotope injection for breast cancer.

BACKGROUND: Controversy exists in the literature regarding the optimal site for lymphatic mapping in breast cancer. This study was designed to characterize lymphatic drainage patterns within the same patient after subareolar (SA) and peritumoral (PT) radiopharmaceutical injections and examine the impact of reader interpretation on reported drainage. METHODS: In this prospective trial, 27 women with breast cancer underwent sequential preoperative SA and PT injections of 0.5 to 2.7 mCi of technetium-99 m filtered sulfur colloid 3 days or more apart. Patterns of radiopharmaceutical uptake were reviewed independently by two nuclear medicine physicians. Inter-reader agreement and injection success were assessed in conjunction with observed drainage patterns. RESULTS: There was near perfect inter-reader agreement observed on identification of axillary LN drainage after PT injection (P = 0.0004) and substantial agreement with SA injection (P = 0.0344). SA injection was more likely to drain to only axillary LNs, whereas PT injection appeared more likely to drain to both axillary and extra-axillary LNs, although no statistically significant differences were found. All patients with extra-axillary drainage after PT injection (n = 6 patients) had only axillary drainage after SA injection. Dual drainage was observed for six patients with PT injection and one patient with SA injection. CONCLUSIONS: Our findings suggest that radiopharmaceutical injected in the SA location has a high propensity to drain to axillary LNs only. After controlling for patient factors and demonstrating inter-reader agreement, the inability to demonstrate statistically significant differences in drainage based on injection site suggests that lymphatic drainage patterns may be a function of patient and tumor-specific features.

Refractory seizures: Prediction of outcome of surgical intervention based on results from PET-CT, PET-MRI and electroencephaolography.

PURPOSE: The purpose of this article is to evaluate the effectiveness of fluorodeoxyglucose (FDG) positron emission tomography (PET)-computed tomography (CT) and PET-magnetic resonance imaging (MRI) with scalp and intracranial electroencephalogram (EEG) in predicting surgical outcomes in patients with refractory seizures. METHODS: Patients who underwent PET-CT and MRI fusion, scalp and intracranial EEG, and subsequent surgical intervention were retrospectively included. PET-CT were fused with MRI and interpreted by an experienced blinded reader. An area of hypometabolism on PET was identified as the location of the epileptic focus. The site of seizure focus was correlated with scalp and intracranial EEG findings. Surgical outcomes were evaluated. Thirty-six patients were included; all had presurgical PET-CT, scalp EEG, and PET-MRI fusion, and 28 of these patients had intracranial EEGs. RESULTS: PET-CT showed concordance of epileptic foci with scalp EEG in 7/36 patients (19%) and with intracranial EEG in 9/28 patients (32%). PET-MRI was concordant with scalp EEG in 6/36 patients (17%) and with intracranial EEG in 8/28 patients (29%). All patients with concordance of epileptic foci between PET-CT and PET-MRI and scalp EEG had improvement or resolution of seizures postintervention, and 89% of patients had concordance between intracranial EEG and PET studies. However, 45% of patients with discordant PET-CT and scalp EEG, 37% with discordance PET-CT and intracranial EEG, 43% with discordant PET-MRI and scalp EEG, and 35% of patients with discordant PET-MRI and intracranial EEG did not improve postsurgically. CONCLUSION: Concordance of epileptic foci localization between PET imaging and EEG yields favorable postoperative outcome in nearly all patients, whereas discordance has an equal probability of favorable vs unfavorable outcomes.

Improving Hepatobiliary Imaging as a Physiologic Test with Superior Clinical Outcomes.

This study aims at prospectively evaluating the difference in the effect of cholecystokinin (CCK) and half-and-half milk (HHM) administered in the same patient on gallbladder contractility and correlation with clinical outcomes. Upon gallbladder visualization during standard hepatobiliary imaging, 0.02 µg/kg of CCK was injected over 3 min, and additional 30 min of dynamic imaging was obtained. Patients with gallbladder ejection fraction (GBEF) <35% after CCK were administered 8 oz of HHM followed by 30 min of imaging. The GBEF was recalculated. The number of patients whom GBEF changed from below 35% (abnormal) after CCK to above 35% (normal) after HHM was recorded. Follow-up of the clinical outcome at 6 months was performed. Fifty patients with abnormal GBEF were prospectively included. The average GBEF after CCK was 14.7% ± 8.5% and after HHM was 30.7% ± 20.8%. The average increase in GBEF with HHM was 16.0% ± 22.2%. The GBEF changed from abnormal to normal in 17 patients (34%). The remaining 33 patients remained abnormal. Clinical outcomes at 6 months were available in 47 patients. Cholecystectomy was performed in 60% of patients with abnormal GBEF with CCK and HHM with resolution or improvement of pain. Two of 16 patients (12%) with abnormal GBEF after CCK but normal after HHM had cholecystectomies with pain improvement, while 8 out of these patients (50%) were diagnosed and treated with other disorders and improved. Hepatobiliary imaging with HHM stimulation is a superior physiologic test which can lower the number of unnecessary cholecystectomies and misdiagnoses as functional cholecystitis.

Does colon cancer ever metastasize to bone first? a temporal analysis of colorectal cancer progression.

BACKGROUND: It is well recognized that colorectal cancer does not frequently metastasize to bone. The aim of this retrospective study was to establish whether colorectal cancer ever bypasses other organs and metastasizes directly to bone and whether the presence of lung lesions is superior to liver as a better predictor of the likelihood and timing of bone metastasis. METHODS: We performed a retrospective analysis on patients with a clinical diagnosis of colon cancer referred for staging using whole-body 18F-FDG PET and CT or PET/CT. We combined PET and CT reports from 252 individuals with information concerning patient history, other imaging modalities, and treatments to analyze disease progression. RESULTS: No patient had isolated osseous metastasis at the time of diagnosis, and none developed isolated bone metastasis without other organ involvement during our survey period. It took significantly longer for colorectal cancer patients to develop metastasis to the lungs (23.3 months) or to bone (21.2 months) than to the liver (9.8 months). CONCLUSION: Metastasis only to bone without other organ involvement in colorectal cancer patients is extremely rare, perhaps more rare than we previously thought. Our findings suggest that resistant metastasis to the lungs predicts potential disease progression to bone in the colorectal cancer population better than liver metastasis does.

Lymphatic mapping and sentinel lymph node detection in women with vaginal cancer.

OBJECTIVE: To determine the patterns of lymphatic drainage from primary vaginal cancers utilizing lymphoscintigraphy and to determine if this clinical information would affect treatment planning. METHODS: For women with newly diagnosed vaginal cancer, pretreatment lymphatic mapping and sentinel lymph node identification were performed using lymphoscintigraphy. In patients who underwent surgery, sentinel lymph nodes were identified intraoperatively using radiocolloid and patent blue dye. The impact of pretreatment lymphoscintigraphy findings on radiation planning in women who received radiation as initial treatment was noted. RESULTS: Fourteen women were enrolled during the study period. At least 1 sentinel lymph node was identified on pretreatment lymphoscintigraphy in 11 patients (79%). The median number of sentinel nodes found per patient was 2, and bilateral sentinel nodes were found in 6 (55%) of the 11 patients with sentinel nodes identified. Among these 11 patients, 5 (45%) had sentinel nodes identified in the groin only, 4 (36%) had sentinel nodes identified in the pelvis only, and 2 (18%) had sentinel nodes identified in both the groin and the pelvis. No relationship was observed between sentinel lymph node location and primary tumor histologic subtype or location. Three (33%) of the 9 women treated initially with radiation therapy had their radiation field altered as a result of the lymphoscintigraphy findings. CONCLUSION: In women with vaginal cancer, lymphatic drainage from the primary lesion does not always follow the lymphatic channels that would have been predicted anatomically. The addition of lymphoscintigraphy to the pretreatment evaluation for women with vaginal cancer may significantly improve comprehensive treatment planning.

Can bone scans guide therapy with radium-223 dichloride for prostate cancer bone metastases?

BACKGROUND: Radium-223 dichloride (Ra-223 Xofigo) has recently been approved as an addition to the host of available therapies in the USA as a treatment option for metastatic castrate-resistant prostate cancer (mCRPC) with bone metastases. This study describes our initial experience in patients treated with Ra-223 dichloride. It attempts to optimize patients' selection for the best outcome from Ra-223 dichloride therapy. METHODS: Consecutive patients who were referred for treatment with Ra-223 dichloride were prospectively followed. Patients' demographics, functional status per the Eastern Cooperative Oncology Group (ECOG) performance score, pain level per the numeric rating score (NRS), prostate-specific antigen (PSA), creatinine, and hematological values were compared at baseline and at the end of therapy. Patients also had a bone scan before starting therapy and at the end of therapy. Patients were divided into the favorable response (FR) group if their pain and/or functional status improved and the unfavorable response (UR) group if they did not improve, deteriorated, or deceased. Bone scan findings before and after Ra-223 dichloride therapy were compared in both the FR and UR groups. RESULTS: Twenty patients were treated with Ra-223 dichloride. Twelve patients had innumerable bone metastases, three patients had super scans, and three patients had two to seven bone lesions. Two patients were lost to follow-up after the first injection. There were eight patients in the FR group and 10 patients in the UR group. Patients with UR had mean ECOG and NRS pain scores of 1.3 and 5.0 versus 0.8 and 4.4 in the FR group. The mean PSA and creatinine levels in the UR group were 445.2 ng/mL and 1.2 mg/dL versus 22.7 ng/mL and 1.1 mg/dL in the FR group. The mean hemoglobin, platelets, and absolute neutrophil values were 11.2 g/dL, 314.9 K/cmm, and 7.3 K/cmm in the UR group versus 11.6 g/dL, 207.0 K/cmm, and 6.2 K/cmm in the FR group. Seven of the eight patients with FR had a bone scan at the end of therapy showing improvement in five patients, a mixed response in one patient, and progression in another patient. Five patients in the UR group completed five or six injections and had bone scans showing flare of bone metastases in three patients, progression in one patient, and improvement in the fifth patient. Three patients in the UR group died after the first or second injections. Two of these patients had baseline super scans and the third one had widespread bone metastases. CONCLUSION: mCRPC patients with lower PSA levels at baseline and fewer bone lesions are more likely to respond favorably to Ra-223 dichloride therapy.

Preserving functional lung using perfusion imaging and intensity-modulated radiation therapy for advanced-stage non-small cell lung cancer.

PURPOSE: To assess quantitatively the impact of incorporating functional lung imaging into intensity-modulated radiation therapy planning for locally advanced non-small cell lung cancer (NSCLC). METHODS AND MATERIALS: Sixteen patients with advanced-stage NSCLC who underwent radiotherapy were included in this study. Before radiotherapy, each patient underwent lung perfusion imaging with single-photon-emission computed tomography and X-ray computed tomography (SPECT-CT). The SPECT-CT was registered with simulation CT and was used to segment the 50- and 90-percentile hyperperfusion lung (F50 lung and F90 lung). Two IMRT plans were designed and compared in each patient: an anatomic plan using simulation CT alone and a functional plan using SPECT-CT in addition to the simulation CT. Dosimetric parameters of the two types of plans were compared in terms of tumor coverage and avoidance of normal tissues. RESULTS: In incorporating perfusion information in IMRT planning, the median reductions in the mean doses to the F50 and F90 lung in the functional plan were 2.2 and 4.2 Gy, respectively, compared with those in the anatomic plans. The median reductions in the percentage of volume irradiated with >5 Gy, >10 Gy, and >20 Gy in the functional plans were 7.1%, 6.0%, and 5.1%, respectively, for F50 lung, and 11.7%, 12.0%, and 6.8%, respectively, for F90 lung. A greater degree of sparing of the functional lung was achieved for patients with large perfusion defects compared with those with relatively uniform perfusion distribution. CONCLUSION: Function-guided IMRT planning appears to be effective in preserving functional lung in locally advanced-stage NSCLC patients.

Preoperative risk stratification using gated myocardial perfusion studies in patients with cancer.

UNLABELLED: Cancer patients frequently have anemia or an altered coagulation state that may affect their risk stratification for perioperative cardiac events. We performed this study to investigate the incidence of perioperative cardiac events in cancer patients who had abnormal stress myocardial perfusion imaging (MPI) results versus cancer patients with normal MPI results. METHODS: We included 394 consecutive cancer patients with normal (n = 201) or abnormal (n = 193) results on MPI studies performed for preoperative risk stratification. MPI was performed within 6 mo before each patient's scheduled operation. All the patients had surgical procedures requiring general anesthesia, except for 18 who had endoscopic or colonoscopic procedures. We retrospectively reviewed their data for the incidence of major cardiac events intraoperatively and for 1 mo postoperatively. We collected data on their cancer type, risk factors for coronary artery disease, MPI findings, risk of operation, and intraoperative or postoperative major cardiac events, which included death, myocardial infarction (MI), and congestive heart failure (CHF). RESULTS: The patients with abnormal MPI results included 97 with ischemia, 80 with scarring, and 16 with mixed scarring and ischemia. The mean left ventricular ejection fraction and end-diastolic volume were 63.8% +/- 9.8% and 82.0 +/- 53.5 mL in the normal MPI group versus 52.1% +/- 13.1% and 118.1 +/- 53.4 mL in the abnormal-MPI group (P < 0.001). There were 9 major intraoperative or postoperative cardiac events (4.7%) in the patients with abnormal MPI results and none in the patients with normal MPI results (P = 0.001). These major events consisted of 3 deaths, 2 acute MIs, 1 non-Q-wave MI, and 3 cases of CHF. Four of these patients had only scarring on their MPI studies, 3 had ischemia, and 2 had scarring and ischemia. CONCLUSION: Normal MPI results have a high negative predictive value for perioperative cardiac events in cancer patients. Abnormal MPI results, whether demonstrating scarring or ischemia, should prompt appropriate perioperative management in patients with cancer to minimize major cardiac events.

Value of positron emission tomography in staging ocular adnexal lymphomas and evaluating their response to therapy.

BACKGROUND AND OBJECTIVE: An observational case series to assess the value of positron emission tomography (PET) in staging ocular adnexal lymphomas and evaluating their response to therapy. PATIENTS AND METHODS: The clinical records of 16 consecutive patients with ocular adnexal lymphoma for whom pretreatment and posttreatment PET scans and corresponding computed tomography (CT) and magnetic resonance imaging (MRI) scans were available were compared. RESULTS: Pretreatment PET scans demonstrated fluorine 18-fluorodeoxyglucose (FDG) positive lesions in 15 orbits of 12 patients. In 1 patient with low-grade follicular lymphoma of the orbit, PET revealed an additional focus of lymphoma in the deltoid muscle that was missed on clinical examination and conventional radiography. All of the posttreatment PET scans showed complete resolution of FDG uptake, suggesting good response to therapy. However, posttreatment CT and MRI scans demonstrated residual masses in 3 patients. CONCLUSIONS: PET is valuable for initial staging of ocular adnexal lymphomas and may be a good adjunct to conventional imaging in evaluation of response to therapy.

The prevalence of myocardial ischemia after concurrent chemoradiation therapy as detected by gated myocardial perfusion imaging in patients with esophageal cancer.

UNLABELLED: The detection of myocardial perfusion abnormalities after radiation therapy (RT) has been investigated previously in patients with lymphoma and breast cancer. However, the prevalence and association of such abnormalities with RT in esophageal cancer patients have not been investigated previously. METHODS: The prevalence of myocardial perfusion abnormalities detected using gated myocardial perfusion imaging (GMPI) in patients with esophageal cancer after RT (RT group) was compared with that in patients with esophageal cancer who did not undergo RT (NRT group). The patients' data were extracted from a prospectively collected database. The results of GMPI that were read by multiple readers were tested further by an expert reader who was unaware of the patients' clinical information. This reader's findings were correlated with the different RT isodose lines as seen in the CT for RT planning. Isodose lines containing the affected segments in GMPI as well as the rest of the left ventricle were recorded. Additionally, information with regard to the mean radiation dose to the heart for each patient was collected. An overall, mean radiation dose to the heart in patients with abnormal GMPI studies was compared with that in patients with normal GMPI studies. RESULTS: Fifty-one patients were included, 26 in the RT group and 25 in the NRT group. The mean and median interval between RT and GMPI was 7.5 and 3.0 mo, respectively. We identified myocardial perfusion defects in 14 patients (54%) in the RT group and in 4 patients (16%) in the NRT group. Eleven patients (42%) in the RT group had mild inferior wall ischemia versus only 1 patient (4%) in the NRT group (P = 0.001). All of the patients with inferior wall ischemia had distal esophageal cancer. The remaining 12 patients in the RT group and 21 patients in the NRT group had normal GMPI results. The mean left ventricular ejection fraction was 59.0% +/- 10.7% in the RT group and 59.3% +/- 9.8% in the NRT group (P = not significant). Good agreement was found between the GMPI results interpreted by multiple readers and those of the single expert reader (kappa = 0.84). In 7 of 10 patients (70%) who had abnormal GMPI results in the RT group, the myocardial perfusion defect was encompassed in RT isodose lines >/= 45 Gy, whereas in only 5 of 20 patients (25%) the normal left ventricle was included in the RT isodose line >/= 45 Gy. CONCLUSION: RT is associated with a high prevalence of inferior left ventricular ischemia, as detected using GMPI in patients with distal esophageal cancer. Most perfusion defects are encompassed within an isodose line >/= 45 Gy in the RT plan.

Usefulness of preoperative lymphoscintigraphy in patients who undergo radical hysterectomy and pelvic lymphadenectomy for cervical cancer.

OBJECTIVE: The purpose of this study was to assess the value of preoperative lymphoscintigraphy before intraoperative lymphatic mapping for sentinel lymph node identification during radical hysterectomy. STUDY DESIGN: Fifty patients underwent intraoperative lymphatic mapping on our institutional review board-approved protocol. The location of sentinel lymph nodes that were found on lymphoscintigraphy and intraoperative lymphatic mapping were compared. RESULTS: Fifteen of 21 patients (71%) with solitary sentinel lymph nodes that were found on lymphoscintigraphy had multiple sentinel lymph node basins found during the operation. Thirteen of 25 patients (52%) with unilateral sentinel lymph node basins that were found on lymphoscintigraphy had bilateral sentinel lymph nodes at intraoperative lymphatic mapping. Of 15 patients with 2 sentinel lymph node locations that were identified on lymphoscintigraphy, 12 patients (80%) had > or = 3 found during the operation. Of the sentinel lymph nodes that were located on the external iliac basin (n = 47) on lymphoscintigraphy, only 20 lymph nodes (43%) were found at that location during the operation. Concordance between the 2 methods was poor. Seven of the 9 patients with lymph node metastases had disease that was limited to the sentinel lymph nodes. CONCLUSION: Preoperative lymphoscintigraphy adds little value over intraoperative lymphatic mapping for sentinel lymph node identification during radical hysterectomy.

Use of lymphoscintigraphy defines lymphatic drainage patterns before sentinel lymph node biopsy for breast cancer.

BACKGROUND: Lymphoscintigraphy (LSG) can identify lymphatic drainage patterns before sentinel lymph node (SLN) biopsy is performed in patients with early-stage breast cancer, but the importance of extraaxillary SLNs seen on LSG is unknown. We assessed whether drainage patterns seen on LSG were associated with histologic findings in axillary SLNs recovered at SLN biopsy. STUDY DESIGN: From a prospectively maintained database, we identified 1,201 clinically node-negative patients with invasive breast cancer who underwent preoperative LSG and axillary SLN biopsy. Patient and tumor characteristics, LSG results, and final SLN pathology results were examined. RESULTS: LSG showed drainage to internal mammary (IM) nodes in 1.6% of patients, axillary nodes in 68.1%, both IM and axillary nodes in 19.8%, and no drainage in 10.3%. Drainage to IM nodes was observed for tumors in all quadrants of the breast. Patients with IM drainage had a younger median age than patients without IM drainage (51.8 versus 58.3 years, respectively; p < 0.001). The intraoperative axillary SLN identification rate was higher when axillary drainage was observed on LSG than when it was not observed (98.7% versus 93.0%, respectively; p < 0.001), but the LSG drainage pattern was not associated with pathologic status of the SLN or number of metastatic SLNs. At a median followup of 32 months, 4 patients had regional nodal recurrence. CONCLUSIONS: Almost one-fourth of patients had lymphatic drainage to the extraaxillary lymph nodes, particularly the IM nodes, seen on LSG. Extraaxillary drainage seen on LSG did not preclude identification of axillary SLNs at operation. Longterm followup of patients with lymphoscintigraphic evidence of extraaxillary drainage is needed to determine whether regional and systemic recurrence patterns differ in these patients.

The value of 99mTc-sestamibi SPECT/CT over conventional SPECT in the evaluation of parathyroid adenomas or hyperplasia.

UNLABELLED: As SPECT/CT technology evolves, its applications and indications need to be evaluated clinically for more efficient and cost-effective use. This retrospective study evaluated the clinical value of simultaneously acquired (99m)Tc-sestamibi SPECT/CT versus conventional SPECT in diagnosing and locating parathyroid adenomas or hyperplasia in patients with primary hyperparathyroidism. METHODS: Immediately and 60 minutes after intravenous administration of 740-925 MBq of (99m)Tc-sestamibi, static planar images of the neck and chest were obtained. SPECT/CT images were acquired 30 minutes after injection. Two experienced masked readers independently evaluated whether conventional SPECT images provided information beyond what was available from the planar images either by changing the diagnosis or by better locating the glands and whether the SPECT/CT images provided information beyond what was available from the planar plus conventional SPECT images. Forty-eight consecutive patients with a clinical diagnosis of primary hyperparathyroidism were included in the study. The 32 whose scans showed positive results underwent surgical resection and were examined histopathologically. RESULTS: Planar and SPECT imaging, with or without CT fusion, identified 89% of the surgically confirmed diseased parathyroid glands. Use of SPECT/CT changed the diagnosis in only 1 patient (2%) from positive to negative and better located the glands in only 4 patients (8%). SPECT/CT was particularly helpful in locating the 2 ectopic parathyroid adenomas diagnosed in this cohort. Tracer retention in diseased glands did not correlate with histologic characteristics. Also, biochemical markers did not correlate with the scan findings. CONCLUSION: SPECT/CT has no significant clinical value additional to that of conventional SPECT for parathyroid imaging except in locating ectopic parathyroid glands. Eliminating the CT acquisition will spare patients the additional time, radiation exposure, and expense.

The impact of DaTscan in the diagnosis of Parkinson disease.

PURPOSE: The aim of this study was to evaluate the impact of DaTscan in a heterogeneous group of patients with movement disorders as well as the degree of confidence in scan findings between different readers. PROCEDURES: A retrospective evaluation of consecutive patients who underwent DaTscan during 1 year was performed. The patients' demographics, symptoms, duration, clinical diagnosis, and medications were collected. The scan findings were categorized by 2 blinded observers on a semiquantitative scale as follows: 0, normal; 1, mild; 2, moderate; 3, marked; and 4, absent uptake for each of the caudate heads and putamina separately. A correlation of the scan findings with the clinical symptoms and diagnosis as well as interobserver agreement was performed. Disagreement was considered when a difference greater than 2 in more than 1 area of the basal ganglia was recorded. Descriptive statistics and κ test for interobserver agreement were used for data analysis. RESULTS: Fifty-seven patients were included (mean age, 63.4 years; 29 men, 28 women). Clinical diagnosis of Parkinson disease (PD) was certain in 26 and uncertain in 31 patients. DaTscan was markedly abnormal in 24 (92%) of 26 patients with certain clinical diagnosis of PD and normal in the remaining 2 (8%). In 31 patients with uncertain diagnosis, 15 (48%) had markedly abnormal scans, 5 (16%) had mild abnormalities, and 11 (36%) had normal scans. Each of the sensitivity and positive predictive value of DaTscan in patients who had certain clinical diagnosis of PD (26 patients) is 92%. Interobserver agreement occurred in 52 (91%) of 57 scans and disagreement in 5 (9%) of 57 (κ = 0.82). There was also a good correlation with laterality of symptoms in 32 (82%) of 39 positive studies. CONCLUSIONS: Markedly abnormal DaTscan is confirmed as the diagnostic pattern for PD. This pattern helps confirm the diagnosis in patients with unclear clinical diagnosis. Good interobserver agreement is easily obtained in reading DaTscans.

The role of 18F-FDG PET in staging and early prediction of response to therapy of recurrent gastrointestinal stromal tumors.

UNLABELLED: Gastrointestinal stromal tumors (GISTs) are gaining the interest of researchers because of impressive metabolic response to the targeted molecular therapeutic drug imatinib mesylate. Initial reports suggest an impressive role for (18)F-FDG PET in follow-up of therapy for these tumors. However, the role of (18)F-FDG PET versus that of CT has not been established. Therefore, we compared the roles of (18)F-FDG PET and CT in staging and evaluation of early response to imatinib mesylate therapy in recurrent or metastatic GIST. METHODS: The study included 54 patients who underwent (18)F-FDG PET and CT scans within 3 wk before initiation of imatinib mesylate therapy. Forty-nine of these patients underwent repeat scans 2 mo after therapy. The numbers of sites or organs containing lesions on (18)F-FDG PET and CT scans were compared. Corresponding lesions on (18)F-FDG PET and CT scans or those confirmed to be malignant in appearance by other imaging modalities or on follow-up were considered true positives. Lesions seen on (18)F-FDG PET or CT scans but not seen or confirmed to be of benign appearance with other imaging modalities or on follow-up were considered false positives. Measurements of the maximum standard uptake value (SUV) on (18)F-FDG PET scans and tumor size on CT scans were used for quantitative evaluation of early tumor response to therapy. RESULTS: A total of 122 and 114 sites and/or organs were involved on pretherapy (18)F-FDG PET and CT scans, respectively. The sensitivity and positive predictive values (PPVs) for CT were 93% and 100%; whereas these values for (18)F-FDG PET were 86% and 98%. However, the differences between these values for CT and (18)F-FDG PET were not statistically significant (P = 0.27 for sensitivity and 0.25 for PPV). This suggests comparable performance of (18)F-FDG PET and CT in staging GISTs. Repeat scans at 2 mo after therapy showed agreement between (18)F-FDG PET and CT scans in 71.4% of patients (57.1% having a good response to therapy and 14.3% lacking a response). Discrepant results between (18)F-FDG PET and CT were recorded for 28.6% of the patients. (18)F-FDG PET predicted response to therapy earlier than did CT in 22.5% of patients during a longer follow-up interval (4-16 mo), whereas CT predicted lack of response to therapy earlier than (18)F-FDG PET in 4.1%. One patient did not undergo long-term follow-up. These findings suggest that (18)F-FDG PET is superior to CT in predicting early response to therapy in recurrent or metastatic GIST patients. CONCLUSION: The performances of (18)F-FDG PET and CT are comparable in staging GISTs before initiation of imatinib mesylate therapy. However, (18)F-FDG PET is superior to CT in predicting early response to therapy. Thus, (18)F-FDG PET is a better guide for imatinib mesylate therapy.

Comparison of bone and 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography in the evaluation of bony metastases in lung cancer.

UNLABELLED: Positron emission tomography (PET) is a proven accurate modality used for the detection of active malignant tumors. The performance of PET in detecting bony metastases, however, has not been adequately investigated. PURPOSE: The aim of this study was to compare the performance of bone and 2-deoxy-2-[18F]fluoro-D-glucose (FDG) PET scans in evaluating bony metastases from lung cancer. PROCEDURE: This retrospective study evaluated 85 patients with lung cancer who underwent both FDG-PET and bone scans within three weeks of each other for initial staging or restaging. The number and sites of bony lesions on FDG-PET and bone scans were correlated. Concordant lesions between the two modalities were considered to be positive for malignancy; discordant lesions were compared with X-rays, computed tomography (CT), magnetic resonance imaging (MRI), and/or follow-up findings. The mean follow-up interval was 7.9 months. RESULTS: Bone scans were positive for lesions in 24 patients and negative in 61 patients while FDG-PET was positive for bony lesions in 17 patients and negative in 65 patients. FDG-PET was indeterminate for rib involvement in three patients having an underlying lung cancer, whom were evaluated separately. A total of 88 and 41 bony lesions were identified on bone scans and FDG-PET, respectively. Correlation of bone scans with other imaging modalities and clinical follow-up findings revealed a sensitivity, specificity, positive and negative predictive value of 81%, 78%, 34%, and 93%, respectively and for FDG-PET 73% (P=0.81), 88% (P=0.03), 46% (P=0.5,) and 97% (P=0.04), respectively. Using bone scans, 10 patients were correctly diagnosed with bony metastases, 54 were correctly diagnosed free of bony metastases, 17 patients were falsely diagnosed with metastases, and metastases were missed in one patient. Using FDG-PET scans, eight patients were correctly diagnosed with bony metastases, 66 were correctly diagnosed free of bony metastases, seven patients were falsely diagnosed with metastases, and one patient had metastases which were missed. Of the three patients with lung cancer close to the chest wall in whom FDG-PET was indeterminate for rib involvement, the bone scans were truly positive for rib involvement in two of them, and truly negative in the remaining patient. CONCLUSIONS: FDG-PET scans demonstrated significantly higher specificity and negative predictive values than bone scans for evaluating bony metastases from lung cancer. On the other hand, bone scans are more sensitive with higher positive predictive values than FDG-PET scans, but the differences were not statistically significant.

Factors affecting left ventricular ejection fraction using automated quantitative gated SPECT.

BACKGROUND: Factors affecting the accuracy of left ventricular ejection fraction (LVEF) quantification using automated quantitative gated SPECT have not been adequately investigated in patients in the clinical setting. Therefore, the authors studied the effect of defect size and Tc-99m tetrofosmin dose on the accuracy of LVEF calculation using the automated QGS program. MATERIALS AND METHODS: Thirty-two consecutive patients underwent gated rest and stress myocardial perfusion SPECT after administration of 8 and 27 mCi Tc-99m tetrofosmin, respectively. The LVEF was obtained for both the rest and stress studies using the QGS program and compared with the LVEF obtained using quantitative echocardiography performed within 2 weeks. Myocardial perfusion defects were recorded as scarring, ischemia, or mixed scarring and ischemia in 12 left ventricular segments. The defect size was evaluated by adding the number of affected segments. RESULTS: The mean LVEF calculated using high-dose stress QGS, low-dose rest QGS, and echocardiography was 49.2% +/- 15%, 46.2% +/- 17% and 48.7% +/- 16.9% respectively, with no statistically significant differences. The LVEF obtained using high-dose stress QGS correlated better with echocardiography than did that obtained using low-dose rest QGS (r = 0.86 versus 0.76). In addition, when the high-dose stress LVEF in the 14 patients with normal myocardial perfusion was compared with that in 11 patients who had one- or two-segment perfusion defects, and 7 patients who had perfusion defects in > or = three segments, there was good correlation with echocardiography in the three patient groups (r = 0.85, 0.88, and 0.91, respectively). CONCLUSIONS: Myocardial perfusion defects do not affect the accuracy of LVEF calculation using automated QGS. High-dose gated myocardial SPECT demonstrated better correlation with quantitative echocardiography LVEF results.

New method for calculating right ventricular ejection fraction using gated myocardial perfusion studies.

BACKGROUND: Quantification of right ventricular ejection fraction (RVEF) is important in patients who have right heart failure or cor pulmonale. When Tl-201 was the primary radiotracer used to evaluate myocardial perfusion, the outline of the right ventricle could vary and was not visualized in most patients. However, visualization of the right ventricle has become easier with the use of Tc-99m-labeled myocardial perfusion agents. PURPOSE: This study describes a new method for quantifying RVEF using gated stress myocardial perfusion (GMP) slices. The results are compared with those of first-pass radionuclide ventriculography (FPRNA) in the same patients. METHODS: Fifty-two consecutive patients referred for routine GMP imaging were included. After administration of Tc-99m tetrofosmin, all patients underwent FPRNA using a single crystal gamma camera and a GMP study. Regions of interest (ROI) were drawn to outline the right ventricular cavity at end diastole and end systole from three pairs of GMP slices. The RVEF was calculated from the number of pixels within the ROIs. The mean RVEF obtained using FPRNA and GMP imaging was 51.8 +/- 10.8% and 51.9 +/- 12.3%, respectively. The two methods showed good correlation with r = 0.81. In addition, there was no significant difference in the RVEFs calculated using these methods (P = 0.85). Bland-Altman analysis also showed good agreement between the two methods (limits of agreement +14.4% to -14.0%, slope = 0.19). Intraobserver and interobserver correlation were evaluated by reanalyzing 12 patients using the new RVEF quantification method and were good at r = 0.87 and 0.82, respectively. Therefore, this is a new convenient method for evaluating RVEF as part of a routine tomographic gated myocardial perfusion study.

Peritoneal carcinomatosis in patients with ovarian cancer: enhanced CT versus 18F-FDG PET/CT.

PURPOSE: The study aimed to evaluate the efficacy of PET/CT in detecting peritoneal carcinomatosis in patients with ovarian cancer and to compare the diagnostic accuracy of FDG PET/CT with that of enhanced abdominal CT. METHODS: The medical records of 46 consecutive patients with ovarian cancer were reviewed, and the presence of peritoneal tumor on (18)F-FDG PET/CT and enhanced abdominal CT scans was also assessed. Imaging results were compared with the pathologic findings obtained by surgery. RESULTS: Pathologic results were positive for peritoneal carcinomatosis in 26 patients and negative in 20 patients. PET/CT correctly detected 25 of 26 patients with peritoneal carcinomatosis and enhanced abdominal CT correctly detected 23 of 26 patients. Sensitivity and specificity for the diagnosis of peritoneal carcinomatosis were 96.2% and 90%, respectively, for PET/CT and 88.5% and 65%, respectively, for enhanced abdominal CT. The accuracy of PET/CT was statistically higher than that of enhanced abdominal CT (93.5% vs 78.3%, P = 0.039). Four distinctly abnormal PET/CT findings of single nodular, multiple nodular, diffuse, and mixed FDG uptakes were identified and corresponded to pathologic findings. CONCLUSIONS: (18)F-FDG PET/CT imaging is efficient in the diagnosis of peritoneal carcinomatosis and its performance is superior to that of enhanced abdominal CT.