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Other Imaging Modalities (other + imaging_modality)
Selected AbstractsDiagnosis of pancreatic cancerHPB, Issue 5 2006Fumihiko Miura Abstract The ability to diagnose pancreatic carcinoma has been rapidly improving with the recent advances in diagnostic techniques such as contrast-enhanced Doppler ultrasound (US), helical computed tomography (CT), enhanced magnetic resonance imaging (MRI), and endoscopic US (EUS). Each technique has advantages and limitations, making the selection of the proper diagnostic technique, in terms of purpose and characteristics, especially important. Abdominal US is the modality often used first to identify a cause of abdominal pain or jaundice, while the accuracy of conventional US for diagnosing pancreatic tumors is only 50,70%. CT is the most widely used imaging examination for the detection and staging of pancreatic carcinoma. Pancreatic adenocarcinoma is generally depicted as a hypoattenuating area on contrast-enhanced CT. The reported sensitivity of helical CT in revealing pancreatic carcinoma is high, ranging between 89% and 97%. Multi-detector-row (MD) CT may offer an improvement in the early detection and accurate staging of pancreatic carcinoma. It should be taken into consideration that some pancreatic adenocarcinomas are depicted as isoattenuating and that pancreatitis accompanied by pancreatic adenocarcinoma might occasionally result in the overestimation of staging. T1-weighted spin-echo images with fat suppression and dynamic gradient-echo MR images enhanced with gadolinium have been reported to be superior to helical CT for detecting small lesions. However, chronic pancreatitis and pancreatic carcinoma are not distinguished on the basis of degree and time of enhancement on dynamic gadolinium-enhanced MRI. EUS is superior to spiral CT and MRI in the detection of small tumors, and can also localize lymph node metastases or vascular tumor infiltration with high sensitivity. EUS-guided fine-needle aspiration biopsy is a safe and highly accurate method for tissue diagnosis of patients with suspected pancreatic carcinoma. 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has been suggested as a promising modality for noninvasive differentiation between benign and malignant lesions. Previous studies reported the sensitivity and specificity of FDG-PET for detecting malignant pancreatic tumors as being 71,100% and 64,90%, respectively. FDG-PET does not replace, but is complementary to morphologic imaging, and therefore, in doubtful cases, the method must be combined with other imaging modalities. [source] Molecular imaging in small animals,roles for micro-CTJOURNAL OF CELLULAR BIOCHEMISTRY, Issue S39 2002Erik L. Ritman Abstract X-ray micro-CT is currently used primarily to generate 3D images of micro-architecture (and the function that can be deduced from it) and the regional distribution of administered radiopaque indicators, within intact rodent organs or biopsies from large animals and humans. Current use of X-ray micro-CT can be extended in three ways to increase the quantitative imaging of molecular transport and accumulation within such specimens. (1) By use of heavy elements, other than the usual iodine, attached to molecules of interest or to surrogates for those molecules. The accumulation of the indicator in the physiological compartments, and the transport to and from such compartments, can be quantitated from the imaged spatial distribution of these contrast agents. (2) The high spatial resolution of conventional X-ray attenuation-based CT images can be used to improve the quantitative nature of radionuclide-based tomographic images (SPECT & PET) by providing correction for attenuation of the emitted gamma rays and the accurate delineation of physiological spaces known to selectively accumulate those indicators. Similarly, other imaging modalities which also localize functions in 2D images (such as histological sections subsequently obtained from the same specimen), can provide a synergistic combination with CT-based 3D microstructure. (3) By increasing the sensitivity and specificity of X-ray CT image contrast by use of methods such as: K-edge subtraction imaging, X-ray fluorescence imaging, imaging of the various types of scattered X-ray and the consequences of the change in the speed of X-rays through different tissues, such as refraction and phase shift. These other methods of X-ray imaging can increase contrast by more than an order of magnitude over that due to conventionally-used attenuation of X-ray. To fully exploit their potentials, much development of radiopaque indicators, scanner hardware and image reconstruction and analysis software will be needed. J. Cell. Biochem. Suppl. 39: 116,124, 2002. © 2002 Wiley-Liss, Inc. [source] Multicenter prospective analysis of newly diagnosed hepatocellular carcinoma with respect to the percentage of Lens culinaris agglutinin-reactive ,-fetoprotein,JOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 12 2001Hiroko Oka Abstract Background and Aim: The Lens culinaris agglutinin-reactive fraction of ,-fetoprotein (AFP-L3) has been reported to be a highly useful marker for hepatocellular carcinoma (HCC) compared with a conventional serum AFP concentration, which allows earlier detection of HCC compared with using other imaging modalities and predicting prognosis after therapy. A collaborative prospective study involving nine Japanese hospitals was conducted to analyze the relationships between the tumor characteristics of a HCC patient and the percentage of AFP-L3/AFP total at the initial detection. Methods: Between 1 October 1996 and 30 September 1997, a total of 388 patients with newly diagnosed HCC were registered. Results: The cut-off level of the percentage of AFP-L3 was altered from 15 to 10%. The AFP-L3-positive HCC patients demonstrated the characteristics of having an advanced tumor, such as the number of tumors, maximum diameter, tumor spread, portal vein invasion, tumor stage, and tumor classification. With the conventional cut-off level of 15% of the percentage of AFP-L3, the malignant characteristics were more definite than that of 10%. However, no significant differences of serum AFP concentration were observed for malignant characteristics such as maximum diameter and histopathological grading. Conclusion: Serum AFP concentration does not reveal a malignancy of HCC, however, the AFP-L3-positive HCC has biologically malignant characteristics, especially portal vein invasion and lower tumor classification, and is an advanced tumor regardless of small tumor size and lower serum AFP concentration. As AFP-L3 shows the tumor characteristics, its presence should be an important factor in the determination of therapy and prognosis of patients. [source] The use of magnetic resonance imaging in the management of pharyngeal penetration injuries in dogsJOURNAL OF SMALL ANIMAL PRACTICE, Issue 2 2008M. J. Dobromylskyj Objectives: To investigate the correlation between the magnetic resonance imaging findings and subsequent surgical findings for a series of dogs presenting with suspected pharyngeal stick injuries to the Animal Health Trust, Newmarket, between 1995 and 2004. Methods: Magnetic resonance imaging findings were reviewed for patients undergoing a scan of the pharyngeal or cervical area for suspected foreign bodies during the years 1995 to 2004. Results: Case signalment, history and clinical signs were similar to those reported in previous studies. Magnetic resonance imaging demonstrated foreign material in six of seven cases where this was present. There was good correlation between diagnosis of a foreign body at magnetic resonance imaging and subsequent surgical identification. Clinical Significance: Compared with other imaging modalities, magnetic resonance imaging is very helpful for this type of injury, especially in chronic cases where radiographic evidence of a foreign body is unlikely. It is a valuable aid in the diagnosis of pharyngeal penetration injury and in surgical planning. [source] 18F-fluorodeoxyglucose,positron emission tomography scanning is more useful in followup than in the initial assessment of patients with Erdheim-Chester diseaseARTHRITIS & RHEUMATISM, Issue 10 2009Laurent Arnaud Objective Erdheim-Chester disease (ECD) is a rare form of non,Langerhans' cell histiocytosis. The aim of this study was to assess the value of whole-body scanning with 18F-fluorodeoxyglucose,positron emission tomography (FDG-PET) in a large cohort of ECD patients from a single center. Methods We retrospectively reviewed all PET scans performed on 31 patients with ECD who were referred to our department between 2005 and 2008. PET images were reviewed by 2 independent nuclear medicine specialist physicians and were compared with other imaging modalities performed within 15 days of each PET scan. Results Thirty-one patients (10 women and 21 men; median age 59.5 years) underwent a total of 65 PET scans. Twenty-three patients (74%) were untreated at the time of the initial PET scan, whereas 30 of the 34 followup PET scans (88%) were performed in patients who were undergoing immunomodulatory therapy. Comparison of the initial and followup PET scans with other imaging modalities revealed that the sensitivity of PET scanning varied greatly among the different organs studied (range 4.3,100%), while the specificity remained high (range 69.2,100%). Followup PET scans were particularly helpful in assessing central nervous system (CNS) involvement, since the PET scan was able to detect an early therapeutic response of CNS lesions, even before magnetic resonance imaging showed a decrease in their size. PET scanning was also very helpful in evaluating the cardiovascular system, which is a major prognostic factor in ECD, by assessing the heart and the entire vascular tree during a single session. Conclusion The results of our large, single-center, retrospective study suggest that the findings of a FDG-PET scan may be interesting in the initial assessment of patients with ECD, but its greater contribution is in followup of these patients. [source] Clinical outcomes of persistent radioiodine uptake in the neck shown by diagnostic whole body scan in patients with differentiated thyroid carcinoma after initial surgery and remnant ablationCLINICAL ENDOCRINOLOGY, Issue 2 2010Eui Young Kim Summary Objectives, To evaluate the clinical outcomes of persistent radioiodine uptake (RAIU) in the neck by diagnostic whole body scan (DxWBS) after initial therapy and the efficacy of the second ablation in patients with differentiated thyroid carcinoma (DTC). Design, Patients with DTC who underwent bilateral surgery and high-dose remnant ablation between 2000 and 2004 were included. Patients with elevated serum stimulated thyroglobulin (sTg) or extensive lateral neck lymph node involvement at initial surgery underwent a second ablation, and patients with undetectable sTg or in very low-risk groups were observed. Results, Among 572 patients, 25 had persistent RAIU in the neck at first DxWBS. After a median 65·7 months of follow-up, five of these patients (20%) had persistent disease, whereas another 20 patients had no abnormal findings by ultrasonography (US) or other imaging modalities. Seven of 20 patients underwent second ablation and 13 were observed. RAIU disappeared spontaneously in about half of the patients in the observation group. There were no significant between-group differences in change of RAIU at follow-up DxWBS (P = 0·62). Serum sTg decreased and eventually disappeared over a few years in both groups. Ablation failure was not an independent risk factor for recurrence (P = 0·169). Conclusions, Neck US and serum sTg, but not DxWBS, were useful diagnostic tools during follow-up of patients with persistent uptake in the neck at DxWBS. A second ablation was not necessary when neck US showed no evidence of disease, especially in patients with very low sTg concentration. [source] Evaluation of endoscopic and imaging modalities in the diagnosis of structural disorders of the ileal pouchINFLAMMATORY BOWEL DISEASES, Issue 9 2010Linda Tang MD Abstract Background: Computerized tomography enterography (CTE), gastrograffin enema (GGE), magnetic resonance imaging (MRI), and pouch endoscopy (PES) have commonly been used to assess ileal pouch disorders. However, their diagnostic utility has not been systematically evaluated. The aims of this study were to compare these imaging techniques to each other and to optimize diagnosis of pouch disorders by using a combination of these diagnostic modalities. Methods: Clinical data of patients from the Pouchitis Clinic from 2003 to 2008 who had a PES and at least 1 additional imaging modalities (CTE, GGE, or MRI) used for evaluation of ileal pouch disorders were retrospectively evaluated. We analyzed the accuracy, sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) with which these tests were able diagnose pouch inlet and distal small bowel and pouch outlet strictures, pouch fistulas, sinuses, and leaks. Subsequently, accuracy was recalculated by combining 2 imaging modalities to see if this could enhance accuracy. Results: A total of 66 patients underwent evaluation with PES and 1 other imaging modality as follows: PES + CTE (n = 23), PES + GGE (n = 34), and PES + MRI (n = 26). The mean age was 41.5 ± 14.5 years, with 28 being female (42.4%). Sixty patients (90.9%) had J pouches and 59 (89.4%) had a preoperative diagnosis of ulcerative colitis. Overall, CTE, GGE, MRI, and PES all had reasonable accuracy for the diagnosis of small bowel and inlet strictures (73.9%,95.4%), outlet strictures (87.9%,92.3%), fistula (76.9%,84.8%), sinus (68.0%,93.9%), and pouch leak (83,93.9%). CTE had the lowest accuracy for small bowel and inlet strictures (73.9%) and MRI had the lowest accuracy for pouch sinus (68.0%). Combining 2 imaging tests can increase the accuracy of diagnosis to 100% for strictures, fistulas, sinus, and pouch leaks. Conclusions: CTE, GGE, MRI, and PES offer complementary information on disorders of the pouch and the combination of these tests increases diagnostic accuracy for complex cases. (Inflamm Bowel Dis 2010) [source] | ||||||||||