Detection of moderate and severe coronary artery stenosis with technetium-99m tetrofosmin myocardial single-photon emission tomography

The aim of this study was to determine the diagnostic accuracy of technetium-99m tetrofosmin myocardial imaging for the localization of coronary artery stenoses of different degrees of severity. Stress-rest single-photon emission tomography (SPET) was performed on separate days in 80 patients (64 males, 16 females; mean age 61 years; 43 patients with previous myocardial infarction; 18 patients with pharmacological stress), within 6 months of coronary angiography. Scintigraphic images were blindly and independently evaluated by three observers. Coronary stenosis was defined as a >50% narrowing in luminal diameter; severe stenosis was defined as a proximal stenosis of >75% or a peripheral stenosis of >90%. Coronary angiography revealed normal coronary arteries or insignificant coronary stenosis in 13 patients and significant coronary stenoses in 67 patients. The sensitivity and specificity of ^99mTc-tetrofosmin SPET in respect of severely stenosed vessels were, respectively, 80% and 65% for the left anterior descending artery (LAD), 100% and 46% for the right coronary artery (RCA) and 58 and 78% for the left circumflex artery (LCx) territories. Considering all the significantly stenosed vessels, a significant decrease in sensitivity was observed for LAD territories (to 59%, P=0.05), and a nonsignificant decrease for RCA (88%) and LCx (47%) territories while specificity values remained essentially unchanged. No significant changes in sensitivity or specificity were observed when regions with previous myocardial infarction were excluded. In conclusion, the sensitivity of ^99mTc-tetrofosmin SPET for the localization of individual stenosed vessels is only moderate when all significant stenoses are considered, but the ability of this technique to predict the location of severe coronary artery stenoses seems satisfactory, with the exception of the low specificity in respect of RCA territories. Received 26 April and in revised form 7 June 1997     

Performance characteristics obtained for a new 3-dimensional lutetium oxyorthosilicate-based whole-body PET/CT scanner with the National Electrical Manufacturers Association NU 2-2001 standard.

This article reports the results of performance measurements obtained for the lutetium oxyorthosilicate (LSO)-based whole-body PET/CT scanner Biograph 16 HI-REZ with the National Electrical Manufacturers Association (NEMA) NU 2-2001 standard. The Biograph 16 HI-REZ combines a multislice (16-slice) spiral CT scanner with a PET scanner composed of 24.336 LSO crystals arranged in 39 rings. The crystal dimensions are 4.0x4.0x20 mm3, and the crystals are organized in 13x13 blocks coupled to 4 photomultiplier tubes each. The 39 rings allow the acquisition of 81 images 2.0 mm thick, covering an axial field of view of 162 mm. The low- and high-energy thresholds are set to 425 and 650 keV, respectively, acquiring data within a 4.5-ns-wide coincidence window. METHODS: Performance measurements for the LSO-based PET/CT scanner were obtained with the NEMA NU 2-2001 standard, taking into account issues deriving from the presence of intrinsic radiation. RESULTS: The results obtained with the NEMA NU 2-2001 standard measurements were as follows: average transverse and axial spatial resolutions (full width at half maximum) at 1 cm and at 10 cm off axis of 4.61 (5.10) mm and 5.34 (5.91) mm, respectively; average sensitivity of 4.92 counts per second per kilobecquerel for the 2 radial positions (0 and 10 cm); 34.1% system scatter fraction; and peak noise equivalent count (NEC) rates of 84.77 kilocounts per second (kcps) at 28.73 kBq/mL (k=1 in the NEC formula; noiseless random correction) and 58.71 kcps at 21.62 kBq/mL (k=2; noisy random correction). CONCLUSION: The new integrated PET/CT system Biograph 16 HI-REZ has good overall performance, with, in particular, a high resolution, a low scatter fraction, and a very good NEC response.     

Confirmation of a new phenotype in an individual with a variant in the last part of exon 30 of CREBBP

We report here a novel de novo missense variant affecting the last amino acid of exon 30 of CREBBP [NM_004380, c.5170G>A; p.(Glu1724Lys)] in a 17‐year‐old boy presenting mild intellectual disability and dysmorphisms but not resembling the phenotype of classical Rubinstein–Taybi syndrome. The patient showed a marked overweight from early infancy on and had cortical heterotopias. Recently, 22 individuals have been reported with missense mutations in the last part of exon 30 and the beginning of exon 31 of CREBBP, showing this new phenotype. This additional case further delineates the genotype–phenotype correlations within the molecular and phenotypic spectrum of variants in CREBBP and EP300.     

Small lesions detectability with the Biograph 16 Hi-Rez PET/CT scanner and fast imaging protocols: performance evaluation using an anthropomorphic thoracic phantom and ROC analyses

Objectives

The purpose of this study was to evaluate the impact on lesion detectability of fast imaging protocols using ¹⁸F-FDG and a 3-dimensional LSO-based PET/CT scanner.

Methods

An anthropomorphic thoracic phantom was used simulating the anatomical structures of radioactivity distribution for the upper torso of an underweight patient. Irregularly shaped targets of small dimensions, the zeolites, were located inside the phantom in an unpredictable position for the observers. Target-to background ratios and target dimensions were selected in order to sample the range of detectability. Repeated imaging was performed to acquire PET images with varying emission scan duration (ESD) of 1, 2, 3 and 4 min/bed and background activity concentrations of 10, 5 and 3 kBq/mL in the torso cavity. Three observers ranked the targets and a receiver operating characteristic analysis was performed for each acquisition protocol.

Results

Detection performances improved when passing from a short (ESD = 1 min) protocol to longer (ESD ≥ 2 min) protocols. This improvement was established with adequate statistical significance.

Conclusions

Short image acquisition times of 1 min/bed using ¹⁸F-FDG and the specific scanner model considered in the study lead to reduced lesion detectability and should be avoided also in underweight patients.     

Treatment decision-making for a post-traumatic malocclusion in an elderly patient: A case report.

Traumatic dental injuries in elderly patients are a rising trend due to demographic and social changes of the population. Older dentulous patients in good health have become increasingly common. The development of a post-traumatic malocclusion is a common sequela resulting from mandibular condyle fracture, as in the case reported in this paper. The decision-making process led the authors to rule out conservative treatment options and to perform orthognathic surgery on an 81-year-old patient, an unprecedented report in the literature. At one-year follow-up, prophylactic therapy, a specific surgical technique, and osteotomy fixation have restored the occlusion to the pre-traumatic condition.     

Prospective evaluation of major vascular events in patients with nonsmall cell lung carcinoma treated with cisplatin and gemcitabine

BACKGROUND: Cancer and cisplatin-based chemotherapy both are well recognized risk factors for coagulation disorders and thrombosis. However, vascular events (VEs) seldom are considered adverse effects of treatment and may not even be taken into account in reports of chemotherapy trials. METHODS: VEs were recorded prospectively in a population of patients with nonsmall-cell lung carcinoma (NSCLC) who were treated consecutively with cisplatin and gemcitabine using a diagnostic flow chart based on a thorough clinical examination, hematologic and coagulative parameters, and imaging assessments when appropriate. RESULTS: From January, 2000 to January 2003, 108 patients with Stage III-IV NSCLC underwent chemotherapy and were evaluated. Overall, 22 VEs occurred in 19 patients (17.6%; 95% confidence interval [95% CI], 10.3-24.8%), including 10 arterial VEs (2 myocardial infarctions, 7 lower limb arterial thrombosis, and 1 ischemic stroke) and 12 venous VEs (3 catheter-related upper limb VEs, 6 venous thrombosis of the lower limb, and 3 pulmonary embolisms). The cumulative proportion of VEs at 1 year after the start of chemotherapy was 22.0% (95% CI, 12.7-31.3%). Four patients died due to the VE (overall mortality, 3.7%), and 3 patients needed surgical revascularization. In the other patients, conservative medical treatment was effective. Baseline patient-related and disease-related characteristics of the patients with VEs did not differ significantly from the characteristics of patients without VE; liver and brain metastases were more frequent in patients with VE, although the difference did not reach statistical significance. Response rates were similar in the two groups. A double VE was detected in three patients who were given further chemotherapy after resolution of the first event. CONCLUSIONS: VEs were a common finding in chemotherapy-treated NSCLC patients. Chemotherapy itself seem to be a powerful risk factor for VE. Strategies to predict the occurrence of VEs should be developed to spare this life-threatening toxicity.