18F-Florbetaben PET/CT to Assess Alzheimer's Disease: A new Analysis Method for Regional Amyloid Quantification.

BACKGROUND AND PURPOSE: While AD can be definitively confirmed by postmortem histopathologic examination, in vivo imaging may improve the clinician's ability to identify AD at the earliest stage. The aim of the study was to test the performance of amyloid PET using new processing imaging algorithm for more precise diagnosis of AD. METHODS: Amyloid PET results using a new processing imaging algorithm (MRI-Less and AAL Atlas) were correlated with clinical, cognitive status, CSF analysis, and other imaging. The regional SUVR using the white matter of cerebellum as reference region and scores from clinical and cognitive tests were used to create ROC curves. Leave-one-out cross-validation was carried out to validate the results. RESULTS: Forty-four consecutive patients with clinical evidence of dementia, were retrospectively evaluated. Amyloid PET scan was positive in 26/44 patients with dementia. After integration with 18F-FDG PET, clinical data and CSF protein levels, 22 of them were classified as AD, the remaining 4 as vascular or frontotemporal dementia. Amyloid and FDG PET, CDR 1, CSF Tau, and p-tau levels showed the best true positive and true negative rates (amyloid PET: AUC = .85, sensitivity .91, specificity .79). A SUVR value of 1.006 in the inferior frontal cortex and of 1.03 in the precuneus region was the best cutoff SUVR value and showed a good correlation with the diagnosis of AD. Thirteen of 44 amyloid PET positive patients have been enrolled in clinical trials using antiamyloid approaches. CONCLUSIONS: Amyloid PET using SPM-normalized SUVR analysis showed high predictive power for the differential diagnosis of AD.

Choline-PET/CT in the Differential Diagnosis Between Cystic Glioblastoma and Intraparenchymal Hemorrhage.

OBJECTIVE: Glioblastoma multiforme (GBM) represents the most common and malignant glioma, accounting for 45%-50% of all gliomas. The median survival time for patients with glioblastoma is only 12-15 months after surgical, chemioterapic and radiotherapic treatment; a correct diagnosis is naturally fundamental to establish a rapid and correct therapy. Non-invasive imaging plays a pivotal role in each phase of the diagnostic workup of patients with suspected for diagnosis. The aim of this case report was to describe the potential clinical impact of 18F-fluorocholine (FCH) PET/CT in the assessment of a cystic GBM mimicking a spontaneous hemorrhage. METHODS: a 57 years-old male with intraparenchymal hemorrhage at CT imaging initially in reduction ad serial imaging and suspected right fronto-temporo-parietal lesion at MRI underwent dynamic and static (60' after tracer injection) FCH PET/CT of the brain. RESULTS: FCH PET/CT showed rapid tracer uptake after few second from injection at dynamic acquisition and consequent incremental mild uptake at static imaging after 60 minutes at the level of oval formation in the right cerebral hemisphere characterized by annular and peripheral high metabolic activity. The central region of the lesion was characterized by the absence 18F-FCH uptake most likely due to blood component. The patient underwent surgery for tumor removal; the histopathological examination confirmed the suspect of GBM. Chemo-radiotherapic adjuvant protocol according to Stupp protocol was therefore administrated; to date the patient is alive without any progression disease at 5 months from treatment. CONCLUSION: In this case report FCH PET/CT represented the final diagnostic technique to confirm the suspicious of a cystic GBM. Our case demonstrated the potential role of 18F-FCH PET/CT for discrimination of higher proliferation area over intraparenchymal hemorrhage, supporting the potential use of this imaging biomarker in surgical or radiosurgical approach. Obviously, further prospective studies are needed to confirm this role and to exactly define possible routinely applications.

Superior Mesenteric Artery Syndrome: Clinical, Endoscopic, and Radiological Findings.

BACKGROUND: The superior mesenteric artery (SMA) syndrome is a rare entity presenting with upper gastrointestinal tract obstruction and weight loss. Studies to determine the optimal methods of diagnosis and treatment are required. AIMS AND METHODS: This study aims at analyzing the clinical presentation, diagnosis, and management of SMA syndrome. Ten cases of SMA syndrome out of 2074 esophagogastroduodenoscopies were suspected. A contrast-enhanced computed tomography (CECT) scan was performed to confirm the diagnosis. After, a gastroenterologist and a nutritionist personalized the therapy. Furthermore, we compared the demographical, clinical, endoscopic, and radiological parameters of these cases with a control group consisting of 10 cases out of 2380 EGDS of initially suspected (but not radiologically confirmed) SMA over a follow-up 2-year period (2015-2016). RESULTS: The prevalence of SMA syndrome was 0.005%. Median age and body mass index were 23.5 years and 21.5 kg/m2, respectively. Symptoms developed between 6 and 24 months. Median aortomesenteric angle and aorta-SMA distance were 22 and 6 mm, respectively. All patients improved on conservative treatment. In our series, a marked (>5 kg) weight loss (p = 0.006) and a long-standing presentation (more than six months in 80% of patients) (p = 0.002) are significantly related to a diagnosis of confirmed SMA syndrome at CECT after an endoscopic suspicion. A "resembling postprandial distress syndrome dyspepsia" presentation may be helpful to the endoscopist in suspecting a latent SMA syndrome (p = 0.02). The narrowing of both the aortomesenteric angle (p = 0.001) and the aortomesenteric distance (p < 0.001) was significantly associated with the diagnosis of SMA after an endoscopic suspicion; however, the narrowing of the aortomesenteric distance seemed to be more accurate, rather than the narrowing of the aortomesenteric angle. CONCLUSION: SMA syndrome represents a diagnostic and therapeutic challenge. Our results show the following findings: the importance of the endoscopic suspicion of SMA syndrome; the preponderance of a long-standing and chronic onset; a female preponderance; the importance of the nutritional counseling for the treatment; no need of surgical intervention; and better diagnostic accuracy of the narrowing of the aorta-SMA distance. Larger prospective studies are needed to clarify the best diagnosis and management of the SMA syndrome.

Effect of observer experience in the differentiation between benign and malignant liver tumors after ultrasound contrast agent injection.

OBJECTIVE: The purpose of this study was to assess the impact of the observer level of experience on the diagnostic performance of contrast-enhanced ultrasound imaging (CEUS) for differentiation between benign and malignant liver tumors. METHODS: From a computerized search, we retrospectively identified 286 biopsy-proven liver tumors (105 hepatocellular carcinomas, 48 metastases, 7 intra-hepatic cholangiocarcinomas, 33 liver hemangiomas, and 93 nonhemangiomatous benign lesions) in 235 patients (140 male and 95 female; mean age +/- SD, 56 +/- 11 years) who underwent CEUS after sulfur hexafluoride-filled microbubble injection. The digital cine clips recorded during the arterial (10-35 seconds from injection), portal (50-120 seconds), and late (130-300 seconds) phases were analyzed by 6 independent observers without experience (group 1, observers 1-3) or with 2 to 10 years of experience in CEUS (group 2, observers 4-6). Specific training in the diagnostic and interpretative criteria was provided to the inexperienced observers. Each observer used a 5-point scale to grade diagnostic confidence: 1, definitely benign; 2, probably benign; 3, indeterminate; 4, probably malignant; or 5, definitely malignant on the basis of the enhancement pattern during the arterial phase and enhancement degree during the portal and late phases compared with the liver (hypoenhancement indicating malignant and isoenhancement to hyperenhancement indicating benign). RESULTS: The analysis of observer diagnostic confidence revealed higher intragroup (kappa = 0.63-0.83) than intergroup (kappa = 0.47-0.63) observer agreement. The experienced observers showed higher diagnostic performance in malignancy diagnosis than did inexperienced observers (overall accuracy: group 1, 63.3%-72.8%; group 2, 75.9%-93.1%; P < .05, chi(2) test). CONCLUSIONS: The diagnostic performance of CEUS in liver tumor characterization was dependant on the observer's level of experience.

Unusual case of left ventricular pseudoaneurysm.

A 71 year-old man with a history of previous anterior myocardial infarction, triple coronary artery bypass graft and left ventricular (LV) aneurysmectomy was admitted to the cardiology unit for chest pain. Physical examination showed a pulsing mass in the left chest wall. Cardiac multislice computed tomography showed a rare case of LV pseudoaneurysm (6.3 x 6 x 10 cm) communicating by a fistulous trait (1 cm) with the left anterior chest wall (C7-C8), creating a subfascial mass (7.1 x 3.6 cm).

The added diagnostic value of 64-row multidetector CT combined with contrast-enhanced US in the evaluation of hepatocellular nodule vascularity: implications in the diagnosis of malignancy in patients with liver cirrhosis.

The aim of this study was to assess the added diagnostic value of contrast-enhanced US (CEUS) combined with 64-row multidetector CT (CT) in the assessment of hepatocellular nodule vascularity in patients with liver cirrhosis. One hundred and six cirrhotic patients (68 male, 38 female; mean age +/- SD, 70 +/- 7 years) with 121 biopsy-proven hepatocellular nodules (72 hepatocellular carcinomas, 10 dysplastic and 15 regenerative nodules, 12 hemangiomas, and 12 other benignancies) detected during US surveillance were prospectively recruited. Each nodule was scanned by CEUS during the arterial (10-40 s), portal venous (45-90 s), and delayed sinusoidal phase (from 100 s after microbubble injection to microbubble disappearance). Nodule vascularity at CEUS, CT, and combined CEUS/CT was evaluated side-by-side by two independent blinded readers who classified nodules as benign or malignant according to reference diagnostic criteria. The combined assessment of CEUS/CT provided higher sensitivity (97%, both readers) than did separate assessment of CEUS (88% reader 1; 87% reader 2) and CT (74% reader 1; 71% reader 2; P < 0.05), while no change in specificity was provided by combined analysis. The combined assessment of hepatocellular nodule vascularity at CT and CEUS improved sensitivity in the diagnosis of malignancy in patients with liver cirrhosis.

[Usefulness of coronary angiography with multidetector computed tomography in the evaluation of aorto-coronary bypass patency]. / Utilità dell'angiografia coronarica eseguita mediante tomografia computerizzata multidetettore nel controllo della pervietà del bypass aortocoronarico.

BACKGROUND: Coronary angiography is actually the gold standard to visualize coronary artery bypass graft patency and to detect bypass stenoses. However, it is an invasive examination that makes use of X-ray emission and it may lead to deleterious effects even at low dosage. Therefore, it is still needed a non-invasive examination with good diagnostic accuracy for the follow-up of patients with coronary artery bypass grafts. The aim of this study was to evaluate the diagnostic accuracy of a 40-row multidetector computed tomography scanner for the assessment of bypass surgery versus coronary angiography. METHODS: Twenty-six consecutive patients (20 male, 6 female, mean age 65 years) and a total number of 68 coronary bypass grafts (25 arterial and 43 venous grafts, 111 anastomoses) were examined by 40-row multidetector computed tomography. RESULTS: It was possible to analyze coronary artery bypass graft patency for every patient. At coronary angiography 23 patients showed bypass stenoses or occlusion: 19 of them were correctly diagnosed by computed tomography (sensitivity 84%, specificity 100%). In particular, computed tomography showed a sensitivity of 90% and a specificity of 100% for coronary artery bypass grafts, whereas it showed a sensitivity of 88% and a specificity of 94% for anastomoses. CONCLUSIONS: On the basis of the results of our study, computed tomography is a valuable tool for assessing coronary artery bypass graft patency in patients with clinical suspect of coronary occlusion.

[Forty-slice multidetector computed tomography for non-invasive diagnostic approach to coronary artery disease]. / Approccio diagnostico non invasive con tomografia computerizzata multidetettore a 40 strati per lo studio della malattia aterosclerotica coronarica.

BACKGROUND: Multidetector computed tomography coronary angiography (MDCT-CA) is a non-invasive technique that clearly shows coronary anatomy and correctly identifies plaque location and morphology. In this study we assessed diagnostic accuracy of MDCT-CA in detectiong significant stenosis in patients with clinically relevant coronary tree disease. METHODS: . Fifty patients (38 males, 12 females, mean age 60.9 +/- 9.2 years) with atypical chest pain, stable or unstable angina pectoris, or non-ST-elevation myocardial infarction underwent MDCT-CA (Brilliance 40, Philips Medical Systems, Cleveland, OH, USA) within 3 days before diagnostic conventional coronary angiography. Inclusion criteria were sinus rhythm, heart rate <70 b/min, and ability to hold breath for more than 12 s. Exclusion criteria were known intolerance to contrast medium, serum creatinine >2 mg/dl, pregnancy, respiratory insufficiency, unstable clinical conditions, and severe heart failure. Beta-blockers were administered if heart rate was >70 b/min. To synchronize arrival of the contrast bolus (Iomeron 400, Bracco, Milan) in the coronary arteries with the start of the scan the bolus-tracking technique was used. Diagnostic accuracy was evaluated per segment, per vessel, and per patient. RESULTS: Mean heart rate during examination was 61.9 +/- 6.2 b/min; 618 segments were evaluated. The assessment was impaired by respiratory artifacts only in 1 patient (2%). MDCT-CA showed good sensitivity, specificity, and positive and negative predictive values in detecting significant coronary artery stenosis (94, 94, 91, and 96% per segment; 91, 97, 95, and 92% per vessel; 100, 100, 100, and 100% per-patient, respectively). CONCLUSIONS: Forty-slice MDCT-CA showed a good diagnostic capability in detecting significant coronary artery stenosis in patients referred to our institution for suspected or known significant coronary artery disease.