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Biomedical subjects

Elliot K Fishman

Publications and source records attributed to Elliot K Fishman.

At least 37 records · Page 2Linked to original sources

IV contrast selection for MDCT: current thoughts and practice.

OBJECTIVE: The purpose of this article is to review studies evaluating how contrast concentration affects MDCT of the body and to report IV contrast infusion protocols from MDCT angiography and MDCT of abdominal tumors. CONCLUSION: Higher concentrations (350 mg I/mL or greater) may improve visualization of small abdominal arteries. However, preliminary data comparing 300 mg I/mL to higher concentrations for MDCT of hypervascular hepatocellular carcinoma and pancreatic cancer have shown that higher concentrations may not increase tumor conspicuity.

Angiography↗

Beta-blockers for cardiac CT: a primer for the radiologist.

OBJECTIVE: The objective of this article is to describe a protocol for the administration of beta-blockers for cardiac CT. A low and regular heart rate is necessary for optimal visualization of the coronary arteries on CT and can be achieved by the administration of medications. CONCLUSION: Beta-blockers can be safely given, orally or IV, to most patients to lower the heart rate for cardiac CT. A protocol can be implemented and patients can be screened for certain contraindications to allow successful administration of these medications by radiologists.

Adrenergic beta-Antagonists↗

Focal nodular hyperplasia: lesion evaluation using 16-MDCT and 3D CT angiography.

OBJECTIVE: The purpose of this article is to present the imaging features of focal nodular hyperplasia (FNH) using MDCT and 3D CT angiography. CONCLUSION: MDCT with advanced image processing is a powerful tool that may be utilized to identify the imaging features of FNH. These include the presence of large feeding arteries and draining veins, pseudocapsule, central scar, and septations. These features can help in the differentiation of this benign lesion from other hypervascular lesions without the need for additional imaging, biopsy, or surgery.

Adult↗

Peliosis hepatis: spectrum of imaging findings.

OBJECTIVE: It is important to recognize the imaging characteristics of peliosis hepatis because peliotic lesions may mimic several different types of focal hepatic lesions CONCLUSION: We illustrate the spectrum of imaging findings of peliosis hepatis, including sonography, CT, MR, and angiography.

Adult↗

Incidental nonneoplastic hypervascular lesions in the noncirrhotic liver: diagnosis with 16-MDCT and 3D CT angiography.

OBJECTIVE: The purpose of this pictorial essay is to review the MDCT features of uncommon hypervascular lesions seen with advanced image processing. CONCLUSION: MDCT with advanced image processing is useful in delineating uncommon hypervascular liver lesions that simulate tumors. Familiarity with the appearance of these lesions may reduce the need for additional imaging, follow-up, and histologic correlation.

Angiography↗

Coronary CT angiography with 64-MDCT: assessment of vessel visibility.

OBJECTIVE: The objective of our study was to evaluate the image quality of 64-MDCT for coronary angiography. SUBJECTS AND METHODS: Fifty consecutive CT coronary angiograms obtained on a 64-MDCT scanner were independently reviewed by two reviewers. Segments were scored as showing no motion (score of 1), minimal motion (2), moderate motion (3), respiratory motion (4), or vessel blurring (5). Opacification was graded as good (score of 1) or limited (2). Segments < 2 mm were graded as well seen; or as poorly seen or not seen. The scores for motion artifact, opacification, and visibility were combined for overall vessel assessment. Segments with a motion score of 1 or 2 that had good opacification and were well seen were judged to be assessable. RESULTS: A total of 714 segments were analyzed in 50 patients. Seven hundred segments were assessed in all patients (segments 1-3, 11-20, 4, or 27), and a ramus intermedius segment was evaluated in 14 patients. Combining the scores for both reviewers, the average motion score was 1 for 619 segments (86.7%), the average motion score for all segments in an individual patient was 1.14 (range, 1-3.35), and the average opacification score for all segments in a patient was 1.02 (range, 1-1.38). A total of 374 segments were less than 2 mm in diameter. Combining the scores for both reviewers, an average of 36 segments (5.0% of 714) could not be identified by the reviewers, 319.5 segments (85.4%) were well seen, and 18.5 segments (4.9%) were poorly seen. Overall, an average of 637 segments (89.2%) were judged assessable by the reviewers. On a per-patient basis, 10 or more vessel segments were judged assessable in 47 patients (94%). CONCLUSION: On 64-MDCT, 89% of coronary artery segments are assessable. Ten or more vessel segments are assessable in 94% of patients.

Adolescent↗

Internet-based dissemination of educational audiocasts: a primer in podcasting--how to do it.

OBJECTIVE: "Podcasting" is a relatively new Internet-based broadcast technology with unique characteristics that may prove valuable in radiologic education. In this article, we describe the procedure for generating, distributing, and downloading a podcast. CONCLUSION: Podcast technology holds promise as an inexpensive method to rapidly and cost effectively disseminate educational Internet audio broadcasts ("audiocasts").

Education, Medical↗

Multifocal neoplastic precursor lesions associated with lobular atrophy of the pancreas in patients having a strong family history of pancreatic cancer.

We screened 116 patients with a strong family history of pancreatic cancer using a combination of endoscopic ultrasound and computed tomography. Ten of these patients underwent surgical resection at our institution, providing an opportunity to define the morphology of pancreatic precursor lesions in patients with a strong family history of pancreatic cancer. Eight of the 10 pancreata were available and these were entirely submitted for histologic examination. The number of pancreatic intraepithelial neoplasia (PanIN) lesions and intraductal papillary mucinous neoplasms (IPMNs) were compared with age-matched controls. Parenchymal changes were defined. Selected precursor neoplasms from 6 pancreata were microdissected and analyzed for KRAS gene mutations. PanINs were significantly more common in the 8 cases (mean of 10.7% of the duct profiles, range 1.0% to 27.3%) than in the controls (mean 1.9%, range 0% to 9.2%, P<0.01). Different KRAS gene mutations were identified in separately microdissected precursor lesions in 2 of 6 cases. IPMNs were identified in 4 of the 8 cases, including 2 pancreata each having 2 distinct IPMNs. Both the IPMNs and the PanINs, even the low-grade PanIN-1 lesions, were associated with lobular parenchymal atrophy. Some individuals with a strong family history of pancreatic cancer develop multifocal, noninvasive epithelial precursor lesions of the pancreas. PanINs and IPMNs produce obstructive lobular atrophy, and this atrophy is likely the source of the chronic pancreatitis-like changes seen in these patients. The multifocal nature of familial pancreatic neoplasia suggests that surveillance of these patients is warranted after partial pancreatectomy.

Adenocarcinoma, Mucinous↗

Initial experience with FDG-PET/CT in the evaluation of breast cancer.

PURPOSE: We retrospectively reviewed FDG-PET/CT images in patients with breast cancer to determine whether PET/CT improved the level of diagnostic confidence as compared with PET and to compare PET/CT and CT findings at the location of suspected malignancies. METHODS: The study included 75 patients with known breast cancer. The initial PET/CT study for each patient was retrospectively reviewed to determine whether improved diagnostic confidence (IDC) regarding lesion localization and characterization was observed with PET/CT as compared with PET alone. PET/CT and CT findings were compared regarding lesion characterization and staging in 69 of the 75 patients, and in the case of discordant findings, comparison with histological or informative follow-up results was also performed. RESULTS: Fifty of the 75 patients exhibited increased FDG uptake in a total of 95 regions. In the comparison of PET/CT and PET, PET/CT resulted in IDC in 30 (60%) of these 50 patients and in 52 (55%) of the 95 regions. In the comparison between PET/CT and CT in 69 patients, PET/CT demonstrated a significantly better accuracy than CT (P<0.05). PET/CT showed definitely positive findings in 60 regions with malignancies, among which CT exhibited positive findings in 43 (72%). PET/CT and CT accurately staged 59 (86%) and 53 (77%) of the 69 patients, respectively. CONCLUSIONS: PET/CT added incremental diagnostic confidence to PET in more than 50% of patients and regions with increased FDG uptake. PET/CT accurately detected more regions with malignancies than did CT. This initial evaluation suggests that PET/CT is preferable to PET or CT in the diagnosis of breast cancer.

Adult↗

Combined PET/CT for detecting recurrent ovarian cancer limited to retroperitoneal lymph nodes.

OBJECTIVE: To evaluate the utility of combined positron emission tomography/computed tomography (PET/CT) for detecting recurrent epithelial ovarian cancer limited to retroperitoneal adenopathy. METHODS: Fourteen patients (median age = 53 years) with rising serum CA125 levels, and negative or equivocal conventional CT imaging > or = 6 months after primary therapy were retrospectively identified as having recurrent disease limited to retroperitoneal lymph nodes by combined PET/CT and underwent surgical reassessment of targeted nodal basins. Fisher's Exact Test was used to measure the ability of PET/CT to predict isolated retroperitoneal nodal disease. RESULTS: The median increase in serum CA125 from baseline nadir was 14 U/ml (range = 2-76 U/ml). There were 29 target nodes in 15 nodal basins identified with increased metabolic uptake on combined PET/CT. Eleven patients (78.6%) had recurrent ovarian cancer in retroperitoneal lymph nodes targeted by PET/CT. Of 143 nodes retrieved, 59 contained recurrent ovarian cancer (median nodal diameter = 2.5 cm, range = 0.8-5.2 cm). For all target nodal basins, the sensitivity, specificity, positive and negative predictive values, and accuracy for recurrent ovarian cancer in dissected lymph nodes were: 40.7% (24/59), 94.0% (79/84), 82.8% (24/29), 69.3% (79/114), and 72.0% (103/143) (P < 0.001). PET/CT failed to identify microscopic disease in 59.3% of pathologically positive nodes. CONCLUSION: Combined PET/CT demonstrates high positive predictive value in identifying recurrent ovarian cancer in retroperitoneal lymph nodes when conventional CT findings are negative or equivocal. The high incidence of occult disease within the target nodal basins suggests that regional lymphadenectomy may be necessary for complete secondary cytoreduction of recurrent disease.

Adult↗

Human immunodeficiency virus 1 infection, cocaine, and coronary calcification.

BACKGROUND: Although cocaine use and human immunodeficiency virus (HIV) infection have been linked with clinical cardiovascular disease, the effects of cocaine use and HIV infection, especially the combination of the 2, on subclinical disease have rarely been reported. The objective of this study was to evaluate whether cocaine use alone, HIV infection alone, or a combination of the 2 is associated with coronary calcification, a marker of subclinical atherosclerosis. METHODS: Between May 20, 2000, and March 31, 2003, 224 black study participants from Baltimore were enrolled in an observational study of subclinical atherosclerosis as related to HIV and cocaine use. Interviews about sociodemographic characteristics and drug use behaviors, clinical examinations, echocardiographic examinations, lipid profiles, high-sensitivity C-reactive protein tests, and computed tomographic scans for coronary calcium were performed. Although the overall investigation is a cohort study, the data presented herein are cross sectional only. RESULTS: The highest proportion (37.6%) of presence of coronary calcification was in the HIV-positive and cocaine-positive group, followed by 29.8% in the HIV-negative and cocaine-positive group, 28.6% in the HIV-positive and cocaine-negative group, and 18.8% in the HIV-negative and cocaine-negative group. Univariate analysis showed that HIV, cocaine use, and both were associated with a higher number of lesions, calcified area, volume, and calcium score. In multiple regression analysis with adjustment for age, body mass index, low-density lipoprotein cholesterol level, triglyceride level, mean corpuscular volume, and systolic blood pressure, HIV, cocaine use, and both were independently associated with coronary calcification. CONCLUSION: These results suggest that HIV infection alone, cocaine use alone, or the 2 combined may contribute to early subclinical atherosclerotic cardiovascular disease.

Adult↗

Distinguishing stress fractures from pathologic fractures: a multimodality approach.

Whereas stress fractures occur in normal or metabolically weakened bones, pathologic fractures occur at the site of a bone tumor. Unfortunately, stress fractures may share imaging features with pathologic fractures on plain radiography, and therefore other modalities are commonly utilized to distinguish these entities. Additional cross-sectional imaging with CT or MRI as well as scintigraphy and PET scanning is often performed for further evaluation. For the detailed assessment of a fracture site, CT offers a high-resolution view of the bone cortex and periosteum which aids the diagnosis of a pathologic fracture. The character of underlying bone marrow patterns of destruction can also be ascertained along with evidence of a soft tissue mass. MRI, however, is a more sensitive technique for the detection of underlying bone marrow lesions at a fracture site. In addition, the surrounding soft tissues, including possible involvement of adjacent muscle, can be well evaluated with MRI. While bone scintigraphy and FDG-PET are not specific, they offer a whole-body screen for metastases in the case of a suspected malignant pathologic fracture. In this review, we present select examples of fractures that underscore imaging features that help distinguish stress fractures from pathologic fractures, since accurate differentiation of these entities is paramount.

Algorithms↗

Acute non-traumatic maternal illnesses in pregnancy: imaging approaches.

The imaging methods used to obtain diagnostic information for pregnant patients presenting with acute non-traumatic maternal illnesses have been reviewed. Conditions affecting the gastrointestinal tract, urinary tract, uterus, adnexae, central nervous system and chest have been investigated via a variety of imaging methods, which include ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), intravenous pyelography (IVP), angiography and fluoroscopy. The method of choice, application, and safety to the mother and fetus are considered for investigation of each condition.

Diagnostic Imaging↗

Multidetector 3D CT of pulmonary embolism of a peripheral intravenous line.

Embolization of foreign objects to the pulmonary circulation is an uncommon occurrence. Traditionally, plain radiographs have been used to detect larger, radiodense objects, with axial CT used to localize smaller, less radiodense objects. More recently, the use of multidetector CT has permitted the detection and accurate localization of smaller, relatively radiolucent objects. This case demonstrates the utility of multidetector 3D CT to localize a small, subtle peripheral venous catheter, which can be easily missed on axial CT.

Adult↗

Optimal contrast agents for vascular imaging on computed tomography: iodixanol versus iohexol.

RATIONALE AND OBJECTIVES: Dimeric nonionic iodinated contrast has a lower osmolality than monomeric nonionic iodinated contrast but is available at lower iodine concentrations. Less dilution of intravascular fluid by influx from the extravascular space is proposed to occur with decreasing osmolality. The purpose of this study was to determine if a dimeric nonionic iso-osmolar contrast agent (iodixanol) gives equal vascular enhancement compared with a monomeric nonionic hyperosmolar contrast agent (iohexol). MATERIALS AND METHODS: A dynamic single-level computed tomography (CT) scan was performed of the abdominal aorta of 12 sedated rabbits using a four-row multidetector CT scanner following injection of 1.5 mL contrast/kg body weight at 2 mL/sec. The rabbits were injected with the dimeric contrast agent iodixanol (Visipaque 320; Amersham Health) or the monomeric contrast agent iohexol (Omnipaque 350; Amersham Health). The order of the type of contrast media injected was randomized for each rabbit, and the interval between injections was 2 weeks. Using the 2.5-mm detectors, four contiguous 3-mm contrast-enhanced scans were obtained at a single level every 5 seconds for 120 seconds (total of 24 scans) with a kVp of 120, mA.s of 110, field of view of 106 mm, and soft tissue reconstruction algorithm. A single level was chosen to measure the attenuation of the abdominal aorta at 5-second intervals. The mean attenuation and standard deviation values were recorded for the whole aorta, for the central half of the vessel, and for the peripheral half of the vessel. A log-log transformation of the data was performed and regression analysis was done on the outcomes of interest (e.g., mean, standard deviation) on time for each region. RESULTS: There was no statistically significant difference in mean attenuation for the whole aorta for iodixanol and iohexol (P = .918) even though the iodine content was 9.3% less with the dimeric iodixanol. The time-attenuation curve of iodixanol paralleled that of iohexol for all time points. The mean attenuation values of the central half of the aorta (P = .354) and peripheral half of the aorta (P = .758) were also not statistically different for the two contrast agents. CONCLUSION: The vascular attenuation provided by a 9.3% lower iodine concentration of iso-osmolar iodixanol is equal to that given by hyperosmolar iohexol. This suggests that there is less intravascular dilution of iso-osmolar contrast. The enhancement across the cross section of the vessel is also similar for both contrast agents. This suggests the vascular studies with iodixanol and iohexol are of equal quality even when a lower dose of iodine is given with iodixanol. It is relevant for patients with borderline or diminished renal function in whom less volume of contrast may be administered.

Animals↗

Women with a low Framingham risk score and a family history of premature coronary heart disease have a high prevalence of subclinical coronary atherosclerosis.

BACKGROUND: The Framingham risk estimation (FRE) serves as the basis for identifying which asymptomatic adults should be treated with aspirin and lipid-lowering therapy in primary prevention. However, the FRE generally yields low estimates of 10-year "hard" coronary heart disease (CHD) event risk with few women (< 70 years) qualifying for preventive pharmacologic therapy despite relatively high lifetime risk. We postulated that traditional risk factor assessment might fail to identify a sizeable portion of women with a sibling history for premature CHD as having advanced subclinical atherosclerosis. METHODS: We studied 102 asymptomatic women (mean age 51 +/- 7 years) who were the sisters of a proband hospitalized with documented premature CHD. Participants underwent risk factor assessment and multidetector computed tomography for coronary artery calcium (CAC) scoring. Based on FRE prediction of 10-year risk for hard CHD events, participants were classified as low risk (< 10%) (n = 100), intermediate risk (10%-20%) (n = 2), or high risk (> 20%) (n = 0). Significant subclinical atherosclerosis was defined as age-sex adjusted > 75th percentile CAC scores. RESULTS: Ninety-eight percent were at low risk (mean FRE of only 2% +/- 2%). However, 40% had detectable CAC, 12% had CAC > 100, and 6% had CAC > or = 400. Based on CAC score percentiles, 32% had significant subclinical atherosclerosis and 17% ranked above the 90th percentile. CONCLUSION: Among women classified as low risk by FRE, a third had significant subclinical atherosclerosis. Sisters of probands with premature CHD appear to be a high-risk group and may warrant noninvasive screening for subclinical atherosclerosis to appropriately target individuals for more aggressive primary prevention therapy than what is currently recommended.

Adult↗

Multidetector CT of hepatocellular carcinoma.

Hepatocellular carcinoma is one of the most common causes of cancer death worldwide. Numerous surgical and nonsurgical treatment options are available for the management of patients with HCC. Successful long-term outcome is dependent on early detection of HCC, as well as accurate delineation of the number and location of tumor nodules. We present the different manifestations of hepatocellular carcinoma as depicted by multidetector-row CT with advanced image processing.

Carcinoma, Hepatocellular↗