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This presentations examines a group of five mummies that were not prepared for the journey to the afterlife but rather preserved and exhibited for commercial enterprise, the sideshow. The study originally comprised five episodes of a forty episode series, «The Mummy Road Show» broadcast on the National Geographic Channel in the United States and internationally. A brief history of the sideshow will be presented to demonstrate the mummies’ roles in the development of that unique segment of the entertainment industry. The method of embalming will be discussed from both its historical context and ability to preserve internal organs. The use of conventional radiography, computed tomography and videoendoscopy to examine the skeletons and well preserved internal organs will be considered in an attempt to substantiate or refute the stories associated with each mummy. In addition, an autopsy conducted on one of the mummies will be correlated to the imaging studies.

Liver hemorrhage, the major cause of death in hepatic trauma, is notoriously difficult to control. We report on the use of high-intensity focused ultrasound (HIFU) to arrest the bleeding from incisions made in rabbit livers. A HIFU transducer, with a spherically curved aperture of 6.34 cm2 area, a focal length of 4 cm and a frequency of 3.3 MHz was used. In approximately 94% of the incisions, the hemorrhage was reduced to a slow oozing of blood in less than 2 min. The maximum temperature of liver tissue around the incision area, during HIFU application, was measured to be 86°C. The mechanism of hemostasis, confirmed by histological examination, appears to be coagulative necrosis of a volume of liver tissue around the incision. We believe that acoustic hemostasis, with the unique characteristic of “volume cauterization”, offers a novel method for the management of liver hemorrhage and, thus, has major clinical implications.

Purpose To investigate performance in detectability of small (≤1 cm) low-contrast hypoattenuating focal lesions by using filtered back projection (FBP) and iterative reconstruction (IR) algorithms from two major CT vendors across a range of 11 radiation exposures. Materials and Methods A low-contrast detectability phantom consisting of 21 low-contrast hypoattenuating focal objects (seven sizes between 2.4 and 10.0 mm, three contrast levels) embedded into a liver-equivalent background was scanned at 11 radiation exposures (volume CT dose index range, 0.5-18.0 mGy; size-specific dose estimate [SSDE] range, 0.8-30.6 mGy) with four high-end CT platforms. Data sets were reconstructed by using FBP and varied strengths of image-based, model-based, and hybrid IRs. Sixteen observers evaluated all data sets for lesion detectability by using a two-alternative-forced-choice (2AFC) paradigm. Diagnostic performances were evaluated by calculating area under the receiver operating characteristic curve (AUC) and by performing noninferiority analyses. Results At benchmark exposure, FBP yielded a mean AUC of 0.79 ± 0.09 (standard deviation) across all platforms which, on average, was approximately 2% lower than that observed with the different IR algorithms, which showed an average AUC of 0.81 ± 0.09 (P = .12). Radiation decreases of 30%, 50%, and 80% resulted in similar declines of observer detectability with FBP (mean AUC decrease, -0.02 ± 0.05, -0.03 ± 0.05, and -0.05 ± 0.05, respectively) and all IR methods investigated (mean AUC decrease, -0.00 ± 0.05, -0.04 ± 0.05, and -0.04 ± 0.05, respectively). For each radiation level and CT platform, variance in performance across observers was greater than that across reconstruction algorithms (P = .03). Conclusion Iterative reconstruction algorithms have limited radiation optimization potential in detectability of small low-contrast hypoattenuating focal lesions. This task may be further complicated by a high degree of variation in radiologists' performances, seemingly exceeding real performance differences among reconstruction algorithms. © RSNA, 2018 Online supplemental material is available for this article.

Introduction: Currently there are no clinically available means of noninvasively detecting early atherosclerotic disease because these lesions are characterized by an accumulation of extracellular lipid and foam cells, but a lack of significant wall thickening or architectural distortion. Objective: We hypothesize that a paramagnetically labeled low density lipoprotein (LDL) could serve as a functional probe to detect sites of abnormal lipid metabolism in the vessel wall that represent sites of early disease. Methods: Isolated LDL was first incubated with manganese–mesoporphyrin, a hydrophobic MR contrast agent (MnMeso). Size exclusion chromatography and absorption mass spectroscopy were performed on the resulting samples to prove that an association between the two occurred. Subsequently, foam cell cultures (n=7) were incubated (10–30 μg/ml for 48 h) with these labeled lipoproteins and the T1 relaxivity of centrifuged pellets of these cells was determined by using an inversion recovery sequence on a 1.5T scanner. These results were compared to control measurements made from foam cell cultures fed unlabeled lipoproteins (n=7). Results: Measured T1 relaxation times of the cells fed the MnMeso–LDL (443.3 ± 51.8 ms) was significantly different from the T1 relaxivity obtained from cells fed unlabeled lipoproteins (661.3 ± 60.9 ms). These findings indicate that the amount of contrast bound to the constructed lipoproteins is sufficient to produce measurable MR signal changes noninvasively. Conclusions: The study results support the feasibility of future in vivo MR experiments with labeled lipoproteins to assess lipoprotein kinetics in the vessel wall, which will hopefully provide a means of detecting early atherosclerotic disease.

Neurolytic celiac plexus block (CPB) under radiological guidance is often performed to manage pain associated with pancreatic cancer. Serious complications related to the block are rare. Computed Tomography (CT)-guided neurolytic CPB is advocated to improve the efficacy of the block and to reduce the incidence of associated complications. We describe a case of superior mesenteric vein thrombosis associated with neurolytic CPB performed under CT guidance.

OBJECTIVE. We describe the imaging findings of venous thrombosis and occlusion after pancreatic transplantation in five patients who underwent multiphasic breath-hold gadolinium-enhanced three-dimensional MR imaging.CONCLUSION. Venous thrombus appeared as serpetine voids within the graft parenchyma or at the venous anastomosis during the venous phase of MR imaging. Nonenhancement or heterogeneous enhancement of graft parenchyma corresponded to glandular necrosis at pancreatectomy in two patients. Initial sonographic evaluation was nondiagnostic of venous thrombosis in two of five patients. Multiphasic breath-hold gadolinium-enhanced three-dimensional MR imaging of pancreatic transplants can provide information to make the specific diagnosis of venous thrombosis or occlusion.

Purpose: To compare patency rates of transjugular intrahepatic portosystemic shunts (TIPS) after placement of long-medium Palmaz stents or Wallstents.

PURPOSE To describe our results with primary placement of the long-medium Palmaz stent for transjugular intrahepatic portosystemic shunts (TIPS). MATERIALS AND METHODS Between December 1997 and December 1998 primary placement of long-medium Palmaz stents was performed for TIPS procedures in 17 patients. Patency was determined with ultrasound, angiography, or pathologic examination in the event of transplant. RESULTS Primary patency was achieved in 13 of 17 patients (76.5%) (follow up, 1–399 days; mean, 99 days). Secondary patency was achieved in 17 of 17 patients (100%) (follow-up, 1–399 days; mean, 110 days). Among the four patients who required revision, the mean time to revision from initial shunt creation was 81 days (range, 13–125 days). Two of these four patients had symptoms of worsening ascites as well as abnormal ultrasound findings prior to their revision; the other two patients were asymptomatic and had abnormal ultrasound findings only. Revisions were performed for intimal hyperplasia within the stent in three of the patients and acute thrombus within the stent in the remaining patient. Kaplan-Meier survival analysis for primary patency yielded mean survival time of 265 days (standard error, 52 days). CONCLUSION The long-medium Palmaz stent is a viable stent for creation of TIPS shunts.

Vascular stenoses were induced in the external iliac arteries of New Zealand white rabbits by a combination of hypercholesterolemic diet and repeat balloon injury. Two-dimensional (2D) and three-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) was performed with a specifically designed phased array coil in a 1.5 T system. Enhancement with gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) hexamethylene diamine co-polymer (Nycomed: NC 22181), a blood pool MR contrast agent, was measured after contrast administration and compared with pre-contrast images at the same levels. Vessel diameter measurements were obtained at multiple levels and compared with comparable levels on conventional angiograms of the same animals. Stable enhancement, averaging 227% above baseline, was observed with the 3D TOF MRA over the 40 minutes of this study. Enhancement was not observed with the 2D TOF technique. Measurement of the smallest vessels in this study with 3D TOF MRA was slightly improved following contrast enhancement, although both pre- and post-contrast diameter measurements tended to underestimate the assumed true vessel diameter. Thus, Gd-DTPA hexamethylene diamine co-polymer (Nycomed: NC 22181), a blood pool MR contrast agent, produces significant, stable enhancement with the 3D TOF technique and may improve MRA measurement of small vessels.

The efficacy of contrast-enhanced magnetic resonance imaging (MRI) for detecting and characterizing, or excluding, hepatic masses was assessed in 404 patients, following the intravenous administration of mangafodipir trisodium (MnDPDP) injection, a hepatic MRI contrast agent. An initial contrast-enhanced computed tomography (CT) examination was followed by unenhanced MRI, injection of MnDPDP (5 μmol/kg IV), and enhanced MRI at 15 minutes post injection. Agreement of the radiologic diagnoses with the patients' final diagnoses was higher for enhanced MRI and for the combined unenhanced and enhanced MRI evaluations than for unenhanced MRI alone or enhanced CT using the clinical diagnosis as the gold standard. Mangafodipir-enhanced MRI uniquely provided additional diagnostic information in 48% of the patients, and patient management was consequently altered in 6% of the patients. MnDPDP-enhanced MRI was comparable or superior to unenhanced MRI and enhanced CT for the detection, classification, and diagnosis of focal liver lesions in patients with known or suspected focal liver disease. J. Magn. Reson. Imaging 2000;12:689–701. © 2000 Wiley-Liss, Inc.

Rationale and Objectives. The purpose of this study was to determine the feasibility of using iodinated liposomes as blood pool agents for computed tomography (CT) in nonhuman primates. Materials and Methods. Five normal adult baboons (15–21 kg) were anesthetized and intravenously injected with iopromide containing soy phosphatidyl glycerol liposomes with a diameter of 195 nm. Each animal received a dose of 300 mg total iodine per kilogram (46% encapsulation). Results. The animals tolerated the injections well, experiencing no measurable electrocardiographic changes, and recovered uneventfully from anesthesia. Sequential helical CT scans of the baboons from the base of the skull to the symphysis pubis acquired up to 40 minutes after injection showed persistent blood pool enhancement. Maximum mean enhancement of major vascular structures was 106 HU at 1 minute after contrast medium injection. Mean blood pool enhancement was 76, 72, and 67 HU at 10, 20, and 40 minutes after injection, respectively. Liver and spleen were enhanced by 40 and 41 HU, respectively, 40 minutes after injection. No significant enhancement was measured in the brain and pancreas. Conclusion. Soy phosphatidyl glycerol with iopromide liposomes produces prolonged vascular enhancement and has potential as a blood pool CT contrast agent in primates.

The purpose of this study was to assess the benefit of combined CT and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in diagnosing malignancy.The records of 26 patients with intraabdominal and intrathoracic neoplasms who underwent CT and FDG PET between January 1995 and September 1996 were retrospectively reviewed. Most of these patients had inconclusive findings on prior CT for the diagnosis of malignancy. Only sites of potential malignant disease were included in the data analysis. Presence or absence of malignancy was confirmed by histopathology or follow-up CT. Three observers experienced in abdominal imaging used CT findings alone to estimate level of suspicion (1 = definitely not malignant to 5 = definitely malignant) for primary or recurrent neoplasms (n = 21), distant metastases (n = 25), and neoplastic nodal involvement (n = 18). Six weeks later the three observers reviewed the same CT examinations supplemented with FDG PET and reestimated suspicion of malignancy. Receiver operating characteristic methodology was used to analyze the results. Sensitivity, specificity, positive and negative predictive values, and accuracy in diagnosis of malignant disease were calculated using level 4 (probable malignancy) as the cutoff for the presence of disease.The mean area under the receiver operating characteristic curve, indicating successful diagnosis of malignancy, was .82 for CT alone and .92 for CT with FDG PET (p.05). The accuracies for diagnosis of primary or recurrent neoplasms, distant metastases, and neoplastic nodal involvement were 62%, 68%, and 83%, respectively, for CT alone and 81% (p = .06), 88% (p = .03), and 89% (p.25), respectively, for CT with FDG PET. Also, supplemental FDG PET imaging improved observer confidence and accuracy in diagnosing recurrent neoplasm in four (36%) of 11 patients who had undergone surgery or chemoradiation and in diagnosing four (29%) of 14 extrahepatic sites that had potential metastases.Diagnosis of malignancy in oncologic patients is significantly improved when CT is supplemented with FDG PET. Combined imaging is particularly helpful in the evaluation of potential recurrence in previously treated patients and for diagnosing extrahepatic lesions that may be distant metastases.

Four rabbits in which atherosclerotic disease was induced by diet and balloon angioplasty underwent conventional angiography and MR angiography (MRA) using a black blood pulse sequence before and 10 minutes after the i.v. injection of a macromolecular contrast agent, NC 100283 (1.0 mmol/kg), a dysprosium diethylenetriaminepentaacetic acid hexamethylenediamine copolymer (Dy-DTPA polymer). Intraluminal signal intensity, apparent wall thickness, and lumen size measurements of the aorta and proximal common iliac arteries on precontrast MRA images were compared with postcontrast images. Aortic lumen diameter measurements on the precontrast and postcontrast MRA studies were compared with lumen diameters from conventional angiograms. Intraluminal signal intensity decreased on postcontrast MRA images compared with precontrast images, with an average loss of signal equal to 29% (P < .05). Apparent wall thickness decreased by 24% (P < .05). Lumen diameter and area were generally larger (average of 15% and 33%, respectively) on postcontrast MRA images than on precontrast images. Aortic lumen diameter measurements from postcontrast MRA agreed closely (95% confidence interval of the mean difference was -.2 to .3 mm), and precontrast MRA images tended to underestimate aortic lumen diameter (95% confidence interval of the mean difference was .3 to .8 mm) compared with conventional angiography. Postcontrast MRA with NC 100283, a macromolecular Dy-DTPA contrast agent, provides more accurate assessment of aortic lumen diameter than precontrast MRA, using conventional angiography as the standard reference.

To determine whether the frontal lobe is disproportionately smaller than normal in second-trimester fetuses with Down syndrome by using prenatal ultrasonographic (US) measurements of the frontothalamic distance (FTD).The FTD, measured from the inner table of the frontal bone to the posterior margin of the thalamus, was measured in 43 fetuses (mean gestational age, 17.2 weeks +/- 1.3 [standard deviation]; range, 15.0-20.4 weeks) with chromosomally proved trisomy 21 and in 160 chromosomally normal fetuses (mean gestational age, 17.1 weeks +/- 1.5; range, 14.5-22.5 weeks). Other cranial biometric ratios also were calculated.The FTD was best predicted from the estimated gestational age (EGA) in the euploid population with the quadratic equation FTD = -0.0120 x EGA2 + 0.6917 x EGA - 5.2349 (R2 = .731) or from the biparietal diameter (BPD) with the linear equation FTD = 0.6837 x BPD + 0.5525 (R2 = .731). If an observed-to-expected ratio of 0.84 is used as a cutoff sign to screen for trisomy 21, a sensitivity of 16%, specificity of 97%, odds ratio of 6.03 (95% confidence interval, 1.81, 20.1), and relative risk of 5.98 are achieved.The frontal lobe is statistically significantly smaller in fetuses with trisomy 21. US measurement of the FTD may prove to be a useful adjunctive screening tool if used with other markers for Down syndrome.

Ultrasonographic contrast agents that stay within the vascular space and do not cross the placenta may permit differentiation between the maternal and fetal portions of the placenta and may be clinically useful for diagnosis of placental abnormalities. This study was performed to assess the effects of Levovist (Schering AG, Berlin) on the placental circulation and to determine whether hemodynamic effects on the fetus occur. Ten studies were performed in five pregnant macaques (median weight, 9.15 kg; range, 6.15 to 11 kg; median gestational age, 121 days; range, 34 days to term) under anesthesia. Gray scale, color, and duplex Doppler sonographic scans of the fetus and placenta were acquired using a 5 MHz curved array transducer. Fetal heart rate, resistive index, and systolic-diastolic ratios were measured in the fetal middle cerebral artery, aorta, umbilical artery, and uterine artery before and after administration of contrast agent. The following dose regimen was tested: 5 ml of physiologic saline solution followed by 0.1 ml/kg of 300 mg/ml Levovist (diagnostic dose), 0. 5 ml/kg of 400 mg/ml Levovist (maximum dose), and 5 ml physiologic saline solution. The order of diagnostic dose and maximal dose was randomized among animals. Color enhancement of the basal portions of the placenta was documented after administration of contrast agent. Heart rate and middle cerebral artery systolic-diastolic ratio did not change between baseline and injections. A 7% decrease of the resistive index from baseline to maximum dose was measured in the uterine artery (not significant). A 7.7% decrease in the systolic-diastolic ratio from baseline to maximum dose was recorded in the umbilical artery. However, an identical change was measured after saline solution was injected. The resistive index in the aorta increased by 2.6% from baseline to maximum dose, a change that was not significant (P > 0.5). Ultrasonographic contrast enhancement of the maternal circulation in placenta is demonstrated to be without significant effects on the fetal circulation as measured in this limited population.

Rationale and Objectives. The authors investigated the effect of oleic acid (cis-9-octadecenoic acid) (OA), a lipidic carrier, on the intestinal absorption rate and T1 relaxation time of manganese (III) mesoporphyrin (Mn-mesoporphyrin), a prototype hepatobiliary contrast agent for magnetic resonance imaging. Methods. Mn-mesoporphyrin was formulated with OA at various concentrations. Small bowel sacs were created in 36 rats and fdled with complexed and free Mn-mesoporphyrin. Intestinal absorption of Mn-mesoporphyrin was measured with spectrophotometry at 364 nm. T1 relaxation times were measured in samples of Mn-mesoporphyrin solutions, bowel wall, liver, and bile. Results. Absorption rates ranged from 4.2%/cm2/h to 13%/cm2/h. Absorption was greatest (13%/cm2/h) when a combination of 1 mmol/L Mnmesoporphyrin and 26.5 mmol/L OA was used. The T1 of bile decreased from 2,480 to 248 msec (maximum decrease) in rats that received Mnmesoporphyrin. Conclusion. Mn-mesoporphyrin is absorbed from the small bowel in both the lipid-associated and free form, resulting in substantial shortening of the T1 in bile.

MR angiography (MRA) for the evaluation of peripheral arterial occlusive disease is a rapidly evolving technique. Recent prospective clinical trials have indicated that MRA may play an important role in the evaluation of patients with peripheral arterial disease. This article discusses the pertinent technical aspects and limitations of peripheral MRA as well as some of the clinical data available.

MR angiography (MRA) has become an increasingly important and practical clinical tool for the noninvasive assessment of abdominal vessels. Both two-dimensional time-of-flight and phase contrast techniques allow accurate evaluation of the portal venous system. This article reviews these two MRA techniques and discusses their impact on the diagnosis of vascular abnormalities of the portal venous system.

CT angiography (CTA) is a promising new technique for vascular imaging. This review focuses first on the technique necessary for successful scanning of the visceral vessels. As in many new modalities, there are different protocols for scanning and rendering of images. The relative strengths and weaknesses of these different approaches are discussed. A discussion of the applications of CTA to depict normal and abnormal anatomy of the visceral vessels follows. These applications include celiac stenosis, splenic artery aneurysms, evaluation for hepatic arterial anatomy before liver transplantation, visceral arterial anatomy in pancreaticoduodenal surgery, the superior mesenteric artery in intestinal ischemia, vascular encasement in patients with pancreatic neoplasms, and, finally, the hepatic vessels before hepatic tumor resection.

Rationale and Objectives. We studied the intestinal absorption of manganese mesoporphyrin (Mn-mesoporphyrin), a potential oral hepatobiliary contrast agent. Methods. Mn-mesoporphyrin was complexed with monoolein and taurocholate (mixed micelles). Portal venous delivery and biliary excretion were measured after intestinal administration in rats and rabbits, and the mechanism of intestinal transport was studied in a combined lymph-bile fistula model in rats. T1-weighted magnetic resonance (MR) images of the liver were obtained in rats and domestic pigs before and after gastric administration of Mn-mesoporphyrin in mixed micelles. Results. A 2.2-fold increase of portal venous Mn concentration was found 90 min after intestinal administration of the complex. None was found in the lymph collected from the thoracic duct, indicating a transcellular transport mechanism through the intestinal mucosa with portal venous delivery. Mn-mesoporphyrin levels in bile peaked between 240 and 270 min after administration (200-fold increase). The greatest liver enhancement (20–90%) was measured 360 min after administration. Conclusion. The feasibility of intestinal delivery of Mn-mesoporphyrin, a lipophilic hepatobiliary contrast agent, was demonstrated.

Rationale and Objectives. We studied the feasibility of using iodinated liposomes as computed tomography (CT) liver contrast agents in nonhuman primates. Methods. Iopromide-containing liposomes were investigated as reticuloendothelial (RES) contrast agents for CT scanning of the liver in normal adult baboons. For intravenous (IV) injection, liposomes were resuspended in mannitol solution, filtered under sterile conditions, and injected IV at doses of 200 and 400 mg I/kg to each of five anesthetized adult baboons. Results. Animals tolerated the injections without measurable electrocardiographic changes and recovered uneventfully from anesthesia. Sequential CT scans of the baboons' upper abdomen acquired up to 60 min postinjection showed persistent enhancement of the liver 10–60 min after injection. Maximum enhancement levels were 36 and 61 ΔHounsfield units (ΔH) after the 200- and 400-mg/kg doses, respectively. The mean time to plateau enhancement was 20 min with the 200-mg/kg dose and 10 min with the 400-mg/kg dose. The greatest splenic enhancements were 181 and 301 ΔH after the 200- and 400-mg/kg doses, respectively. Conclusion. Iopromide liposomes are effective as RES contrast agents in primates.

Purpose Because of a potential impact on thrombus formation, this study determines the degree of blood back flow into catheters filled with different fluids. Materials and Methods Catheters filled with saline or non-ionic or ionic contrast medium were placed in pulsatile circulating human blood in vitro. Catheter orientation was varied, and blood back flow was recorded. Results When the leading end of the catheter was angled downward, blood back flow into a contrast material–filled catheter was far greater than that into a saline-filled catheter (7.0 vs 0.5 cm). Conversely, when the leading end of the catheter was horizontal, blood back flow was much greater when the catheter contained saline versus contrast media (3.6 vs 0.4 cm). Ionicity of contrast material did not affect back flow. Conclusion Back flow of blood into a catheter can be considerable and is dependent on the type of fluid within the catheter and orientation of the leading end of the catheter. Angiographic techniques adjusted to these findings are important to maintain patient safety.

Rationale and Objectives. Macromolecular “blood-pool” agents such as polylysine-gadopentetate dimeglumine or albumin-gadopentetate dimeglumine, which provide prolonged intravascular enhancement, were tested as magnetic resonance (MR) angiography contrast agents for the portal vein in pigs. Methods. Phase-contrast MR angiography of the portal veins was performed on six pigs before and after intravenous administration of polylysine-gadopentetate dimeglumine (n = 3) or albumin-gadopentetate dimeglumine (n = 3). Results. The contrast-to-noise ratio of the portal veins was improved by 74% and 52%, respectively, using polylysine-gadopentetate dimeglumine or albumin-gadopentetate dimeglumine. More branches of the intrahepatic portal veins were visualized on postcontrast images. Conclusion. Blood-pool paramagnetic contrast agents improved the visualization of hepatic vasculature using phase-contrast MR angiography in our experimental model.

Rationale and objectives The feasibility of targeting iodinated contrast agents to the exocrine pancreas was investigated. Iodinated weak organic acids including succinic acid-mono-3-amino-2,4,6-triiodo- N-ethylanilide (compound I), the ethanolamine salt of N-ethylsuccinic acid-(2,4,6-triiodo-3-methylamino anilide) (compound II), and the sodium salt of 2,4,6-triiodo-3-N-ethylacetylamino-phenylpropionic acid (compound III) were studied as potential contrast agents for computed tomography (CT) of the pancreas. Methods An ex vivo perfusion system was used to compare pancreatic uptake of the three compounds. In vivo CT studies were conducted using domestic pigs to study potential enhancement of the pancreas after intravenous injection of the compound. Results Ex vivo perfusion studies with isolated rat pancreas demonstrated nearly identical extraction ratios of approximately 0.6 for all three compounds tested. Average iodine concentrations measured in pancreas at the end of the perfusion studies was 0.27 mg/g +/- 0.20 for compound I, 0.18 mg/g +/- 0.06 for compound II, and 0.16 mg/g +/- 0.09 for compound III. Differences in iodine concentrations retained were not statistically significant. Computed tomography studies in domestic pigs demonstrated up to 30% enhancement of the pancreas after intravenous injection of 75 and 150 mg/kg of compound II at 45 minutes. Whereas ex vivo perfusion studies indicated increasing extraction of the three compounds with increasing doses/concentrations in the perfusate, no improved contrast enhancement was observed at the higher dose level compared with the lower dose in CT. Conclusion Both ex vivo perfusion studies and dose-independent enhancement levels achieved seem to indicate a transport maximum in the pancreas for the iodinated weak organic acids studied.

Three-dimensional (3D) magnetic resonance imaging allows thin-section acquisition and therefore more accurate multiplanar reconstruction than conventional two-dimensional spin-echo imaging. Unfortunately, addition of a third acquisition plane extends imaging time greatly. With gradient-echo techniques, 3D acquisitions have become clinically useful. These techniques are limited, however, by susceptibility and other field inhomogeneity artifacts and decreased signal-to-noise ratios compared with spin-echo techniques. The authors describe implementation of a true spin-echo 3D technique that, by using fast spin-echo parameters, reduces acquisition time to a clinically useful level. Potential applications of the technique are demonstrated.

Objectives Manganese (III) mesoporphyrin (Mn-mesoporphyrin) was investigated for its pharmaceutical properties and magnetic resonance imaging characteristics as a potential hepatobiliary contrast agent. Methods Solubility, partition coefficient, plasma binding, proton relaxation enhancement, biodistribution, biliary excretion, liver extraction ratio, and liver enhancement were measured in various in-vitro and in-vivo systems. Results Mn-mesoporphyrin was soluble and stable at moderate alkaline pH in phosphate buffer. The octanol/water coefficient was 25.98, and the compound was highly protein bound. R1 for water and plasma were 1.94 and 2.35 L/mmol sec, respectively. R1 in liver was calculated to be 15.72 L/mmol sec. Biodistribution studies in rats and mice confirmed hepatotrophic properties and biliary excretion was 65% over 24 hours. First pass liver uptake was 15%. Magnetic resonance imaging studies showed persistent liver enhancement at 0.05 mmol/kg. Conclusion Mn-mesoporphyrin is a lipophilic compound that shows potential as a hepatobiliary magnetic resonance contrast agent.

OBJECTIVES Manganese (III) mesoporphyrin (Mn-mesoporphyrin), a synthetic and stable complex, was investigated for its hepatic magnetic resonance imaging (MRI) properties and compared with manganese tetrakis-(4 sulfonatophenyl) porphyrin (Mn-TPPS4). METHODS Liver abscesses (n = 10) and tumors (n = 14) were induced in rats. These rats then underwent MRI at 2.0 T. Animals received one of the two contrast agents, and measurement of lesion enhancement was performed. RESULTS At an intravenous dose of 0.035 mmol/kg, Mn-mesoporphyrin caused significant enhancement of normal liver parenchyma and increased the lesion-to-liver contrast in both the models of heptic liver abscess and metastatic liver disease. Mn-TTPS4 at an intravenous dose of 0.04 mmol/kg typically enhanced both lesion and normal liver parenchyma and therefore did not improve the lesion-to-liver contrast. CONCLUSIONS The hepatotrophic properties of Mn-mesoporphyrin indicate its potential as an intravenous contrast agent for liver imaging.

To reevaluate blood flow patterns in the normal epididymis with color Doppler sonography.Twenty-seven healthy volunteers (aged 19-68 years) with no history of scrotal disease, infection, or surgery (including vasectomy) underwent gray-scale imaging, color Doppler imaging, and pulsed Doppler spectral analysis of the head, body, and tail of each epididymis. All volunteers had negative results of urinalysis.In each of the 54 epididymides, blood flow was detected with pulsed Doppler and color Doppler imaging 100% of the time in the head, body, and tail. The mean resistive indexes for the right epididymal head, body, and tail were 0.55, 0.55, and 0.58, respectively. Similar values for the left side were 0.54, 0.55, and 0.55, respectively. None of these values were statistically significantly different.With current ultrasound imaging technology, epididymal flow was demonstrated not only in the head but also in the body and tail of the epididymides of all of our healthy volunteers. Thus, detection of flow in the epididymis at color Doppler imaging can be a normal finding and does not necessarily imply epididymitis.

PURPOSE: To evaluate the ability of power Doppler ultrasonography to depict changes in renal perfusion after pharmacologic manipulations. MATERIALS AND METHODS: Six domestic swine were intubated and anesthetized. The right renal artery was catheterized for injection of epinephrine (100 micrograms) and papaverine (2 mg/kg). Intraarterial blood pressure, heart rate, and oxygen saturation were measured continuously. Longitudinal images of the kidney were obtained, and the power Doppler color map was analyzed subjectively and by computer at baseline and at the time of maximum drug effect. RESULTS: Epinephrine produced vasoconstriction with a diminished power Doppler color map and a decrease in both subjective and computer scores. After papaverine-induced vasodilatation, the power Doppler map was enhanced, as reflected by increased subjective and computer scores. CONCLUSION: The power Doppler color map reflects anticipated changes in renal perfusion after alterations in blood flow by vasoactive drugs.

To determine the safety and efficacy of ferumoxtran 10-enhanced magnetic resonance (MR) imaging for diagnosis of metastases to lymph nodes and the clinical usefulness of ferumoxtran 10 in nodal staging.One hundred fifty-two patients were injected with ferumoxtran 10. Readers independently evaluated precontrast MR images by using node size criteria and subjective assessment of other imaging features. Ferumoxtran 10-enhanced MR images were evaluated alone and paired with precontrast images for comparison. The diagnostic performances of precontrast MR size criteria and postcontrast MR imaging were evaluated with receiver operating characteristic (ROC) analysis. Lymph node signal intensity was correlated with histopathologic findings. MR imaging and histopathologic nodal stages were compared.Node-level sensitivity, specificity, and accuracy of precontrast MR imaging were 54%, 82%, and 68%, respectively, with node size criterion alone; 91%, 51%, and 71%, respectively, with subjective reader assessment; 85%, 85%, and 85%, respectively, with postcontrast MR imaging alone; and 83%, 77%, and 80%, respectively, with paired pre- and postcontrast MR imaging. Compared with size criteria, subjective reader assessment had higher sensitivity but substantially lower specificity. Areas under the ROC curve for pre- and postcontrast MR imaging were 0.76 and 0.83, respectively. Nonmetastatic nodes had significantly lower signal intensity than metastatic nodes on postcontrast T2-weighted MR images (P.001). Postcontrast nodal staging was significantly more accurate than precontrast nodal staging (P.01). Headache, back pain, vasodilatation, and urticaria each occurred in 6% of patients.Ferumoxtran 10-enhanced MR imaging was safe and effective and facilitated improved diagnostic performance. Use of iron oxide-enhanced MR imaging increased the positive predictive value by 20% and the accuracy by 14% compared with reader assessment. Differentiating patients with no nodal metastatic involvement was more reliable with ferumoxtran 10-enhanced MR imaging than with precontrast MR imaging.

Background: Hyperattenuating nodules detected by arterial phase helical computed tomography (HCT) in patients with cirrhosis usually are believed to represent hepatocellular carcinomas (HCCs). We correlated HCT morphology of hyperattenuating hepatic nodules detected during arterial phase scans with the histopathology of explanted livers of patients with hepatic cirrhosis undergoing liver transplantation. Methods: Three hundred fifty-four patients had arterial and portal phase HCT performed before subsequent hepatic transplantation. Each patient received 180 mL of contrast by power injection at 5 mL/s. All hyperattenuating nodules detected on arterial phase HCT were assessed for morphology and evidence for contrast enhancement. Explanted livers in all patients were then sectioned at 10-mm intervals, and the histology of the nodules was correlated with the HCT findings. Results: Sixty-one hyperattenuating nodules were detected on the arterial phase HCT in 43 patients: 41 nodules were benign regenerating nodules (RN), three were dysplastic nodules (DP), and 17 were HCCs. Most RN/DP nodules were 5–20 mm in diameter, had distinct margins, were homogeneous, and were isoattenuating on precontrast, portal, and delayed scans. Thirty-six showed positive contrast enhancement and displayed a wide range of attenuation profiles. HCC nodules were 6–50 mm. All showed positive contrast enhancement and displayed a wide range of attenuation profiles. Conclusion: Hyperattenuating nodules seen on arterial phase HCT are likely to be RN/DP nodules. In many cases, it is not possible to distinguish between RN/DP and HCC. Thus, clinical decisions regarding inclusion criteria for transplantation based on CT morphology of liver lesions may be tenuous.

Purpose To determine the feasibility of using a multiphasic magnetic resonance (MR) examination to evaluate the hepatic arterial anatomy and parenchyma in patients awaiting orthotopic liver transplantation (OLT). Materials and Methods Twenty consecutive patients awaiting OLT underwent multiphasic MR (using a T1-weighted 3D gadolinium-enhanced gradient-echo (GRE) sequence and two separate injections of contrast material) and computed tomography (CT) imaging; both imaging studies were performed within a 1-week period for each patient. Quantitative and qualitative assessment of the hepatic arterial system on MR data was performed. Two independent observers classified the hepatic arterial anatomy and evaluated the hepatic parenchyma from the MR data. The prospective CT interpretation was used as the gold standard. Results Overall qualitative rating of hepatic arterial system-to-background contrast on MR data was good to excellent (average pooled score of 2.00 ± 0.27), with no significant difference between the two observers after the first or second injections of contrast material. Classification of hepatic arterial anatomy by MR angiography (MRA) and CT angiography (CTA) was concordant in 85% (17/20) of patients and discordant in 15% (3/20) of patients. Focal parenchymal lesions were detected in 25% (5/20) of patients by MR and CT; however, two lesions in one patient with multiple lesions were detected only with MR. Conclusion Multiphasic T1-weighted 3D gadolinium-enhanced MR examination can provide comprehensive evaluation of the hepatic arterial anatomy and parenchyma in patients awaiting OLT. MR may offer an advantage over CT in the detection of focal parenchymal lesions. J. Magn. Reson. Imaging 2002;16:565–575. Published by Wiley-Liss, Inc.

The purpose of this study was to determine the usefulness of contrast-enhanced sonography in the detection of acute parenchymal injury.In a model of acute renal injury in pigs, four separate renal parenchymal bleeds were created by puncturing an interlobar artery of the upper and lower poles of the kidneys. B-mode gray-scale scans of the kidneys before and after injury, and after the administration of i.v. and intraarterial (i.a.) contrast agents were recorded on videotape for 5 min for each condition (baseline, after injury, after i.v. contrast administration, and after i.a. contrast administration). For each condition and injury, selected frames were analyzed with regions of interest of the normal renal parenchyma, the area of injury, and the perinephric space. Randomized videotape clips from each of the experimental conditions were rated by three sonologists as to the presence or absence of increased intrarenal parenchymal echogenicity, perinephric echogenicity, and confidence as to whether renal injury was present.Areas of renal injury were isoechoic with normal parenchyma on unenhanced scans. After both i.v. and i.a. contrast material injection, areas of injury were visible as areas of increased echogenicity. Contrast increased from 0.2 on unenhanced images to 4.0 and 4.5, respectively, after i.v. and i.a. administration of the new contrast agent. The three observers' ability to diagnose renal injury increased from 0.61, 0.64, and 0.54 to 0.71, 0.70, and 0.74 after i.v. injection and to 0.93, 0.92, and 0.97 after i.a. injection as indicated by the area under the curve in the receiver operating characteristic analysis.Transabdominal contrast-enhanced gray-scale sonography can reveal the area of acute renal hemorrhage. This procedure may be applicable in patients when sonographic contrast agents, imaging procedures, and modes of contrast administration are optimized for clinical use in trauma.

OBJECTIVE To determine whether the association of manganese III mesoporphyrin (MnMeso), an oral MR contrast agent, to oleic acid (OA) vesicles will improve absorption and delivery of MnMeso to the liver. METHODS MnMeso or MnMeso-OA vesicle suspension was intraduodenally administered to rats and the time course of MnMeso concentration in plasma, bile, and intestinal solution was determined. Tissue concentrations of MnMeso in the liver were also determined. RESULTS Association of MnMeso to OA reduced the time it took to reach one-half absorption maximum, TC50, and enhanced the rate and the extent of biliary elimination of this contrast agent. In addition, the results obtained from dose-titration studies indicate that MnMeso-OA vesicle complex may enhance MnMeso accumulation in the liver, observed as a lower dose required to reach equivalent tissue concentration. Taken together, complexion to OA vesicles may provide rapid absorption, enhanced liver accumulation, and efficient elimination of MnMeso. CONCLUSIONS Association with OA vesicles may enhance the rate of MnMeso absorption and biliary excretion while promoting the extent of liver accumulation of MnMeso in rats. This strategy may provide a means to provide safe and effective use of MnMeso as an MR contrast medium.

Clinical diagnostic ultrasound (US) is experiencing an expanding role that is well suited to application on the International Space Station (ISS). Diagnostic US can be used to reduce the risks associated with long duration human space flight by providing a non-invasive tool with head-to-toe diagnostic capability in both biomedical research and crew health care. General health care of the astronauts will be diagnosed with US, e.g., kidney stones, gall bladder disease, appendicitis, etc. Initial studies will focus on detection of “ureteral jets” in the bladder. This is a non-invasive test to rule out obstructive uropathy from kidney stones with minimal requirements for crew training. Biomedical research experiments, focusing on the effects of the microgravity environment, will be performed using both the HHU and the HDI 5000. US will be used to evaluate bone density and muscle mass in this environment. Prolonged or emergency EVAs may occur with the ISS. The hand-held ultrasound unit (HHU) and its telemedici...

The clinical symptoms and morbidity that result from carotid artery disease, the primary cause of stroke, are mainly due to plaque ulceration, thrombosis, intraplaque hemorrhage, and thinned fibrous caps. The contents of atherosclerotic plaques of the carotid artery can be determined with in vivo high-resolution magnetic resonance imaging with flow suppression. Eight patients scheduled to undergo endarterectomy and four healthy volunteers were imaged with a 1.5-T imager and custom-made carotid phased-array coils. T1-weighted spin-echo images and cardiac-gated proton-density--weighted fast spin-echo images were acquired. In vivo imaging findings as determined by three radiologists were correlated with ex vivo imaging and histologic findings. Among the eight plaque specimens, regions of hemorrhage, calcium, lipid deposits, and fibrous plaques were identified on T1- and proton-density-weighted images. Calcium and lipid deposits were detectable on both T1- and proton-density--weighted images. Hemorrhage and fibrous plaques were better demonstrated on proton-density--weighted images.

The purpose of this study was to assess the effectiveness and safety of Gadolite Oral Suspension as a gastrointestinal (GI) contrast agent for MRI in a phase II and two phase III multicenter clinical trials. Gadolite was administered to 306 patients with known or suspected abdominal and/or pelvic disease. MRI with T1- and T2-weighted sequences was performed before and after ingestion. Efficacy was evaluated by having two masked readers rate the certainty of their MR diagnosis (0 = uncertain, 1 = probable, 2 = definite) on randomly presented pre- and post-Gadolite Oral Suspension enhanced images. Principal investigators also evaluated the images and established the final diagnosis. Vital signs, clinical chemistries, and adverse events were documented. Blood and urine samples were analyzed for gadolinium content to determine whether Gadolite Oral Suspension was absorbed systemically. Certainty in MR diagnosis increased significantly (P < .001) for both blinded readers between pre- and post-Gadolite images (.49-1.18 for reader 1: .46-1.53 for reader 2). Sensitivity, specificity, and accuracy also increased for both masked readers. No gadolinium was detected in blood or urine samples. There were no serious adverse events and no apparent drug-related trends in mean vital signs or laboratory values. Gadolite is a highly effective, safe, and well tolerated contrast agent for clinical use with MRI.

To compare liver lesion detection rates, tissue signal and noise data, and qualitative parameters for breathhold (BH) and non-breath-hold (NBH) hybrid rapid acquisition with relaxation enhancement (RARE) and conventional spin-echo (CSE) T2-weighted (CSE-T2) MR sequences, 20 patients were imaged using all three sequences. Lesion detection rates were 73.5% for the CSE-T2 sequence and 81.1% and 88.6% for the BH-RARE and NBH-RARE sequences, respectively (P = .027). Mean lesion-to-liver signal-difference-to-noise ratio for the NBH-RARE sequence was 14.0 ± 11.5, significantly greater than 9.8 ± 7.8 obtained for the BH-RARE sequence (P = .050) and 9.0 ± 6.2 obtained for the CSE-T2 sequence (P = .015). The NBH-RARE sequence demonstrated fewer artifacts and greater overall image quality compared to the CSE-T2 sequence. The NBH-RARE sequence is a useful alternative to the CSE-T2 sequence providing a higher mean lesion-to-liver signal-difference-to-noise ratio and lesion detection rate and better overall image quality.

We investigated the interaction between manganese(III)mesoporphyrin (MnMeso), a metalloporphyrin, and liposome membranes containing oleic acid (OA; cis-9-octadecenoic acid). MnMeso associates preferentially with OA but minimally with egg phosphatidylcholine (EPC). Using small unilamellar vesicles, we characterized the MnMeso-OA binding at neutral pH. Our data suggest that MnMeso binds to the OA bilayer with Kd = 6.8 x 10(-4) M; the binding stoichiometry of MnMeso-OA was 1:3.4. This OA-MnMeso interaction was analyzed further for changes in the T1 relaxation property of MnMeso. OA increased the T1 of MnMeso significantly more than did EPC, suggesting that the OA-MnMeso interaction was stronger than that of PC-MnMeso. The side-chain specificity of the OA interaction with this porphyrin derivative was further supported in an experiment with manganese mesotetra(4-sulfonatophenyl)porphine, which lacks hydrophobic side chains for OA interaction. The association of MnMeso with the OA membrane was proposed according to the structure of MnMeso and OA and further verified using electron microscopy. A strong association of MnMeso with OA, an absorption enhancer of the gastrointestinal tract, may be useful for delivery of MnMeso as an oral contrast agent for magnetic resonance imaging.

Finding and identifying hepatic neoplasms in patients with diffuse liver disease is one of the most challenging tasks in diagnostic radiology. This chapter discusses the performance of contrast enhanced CT (CECT), delayed iodine CT scan (DIS), magnetic resonance imaging (MR) and ultrasound (US) in detection and characterization of focal liver lesions in patients with diffuse liver disease. First, the sensitivity and specificity of these various imaging modalities for detection of focal lesions in patients with normal liver parenchyma is summarized. In the second part, the impact of diffuse liver disease on lesion detection is outlined. Finally, future strategies for the use of contrast agents targeted to liver in patients with diffuse liver disease are outlined.

Rationale and Objectives. We investigated the potential of manganese (III) mesoporphyrin (Mn-mesoporphyrin) as a hepatobiliary contrast agent for magnetic resonance (MR) imaging in rabbits given VX-2 carcinoma liver implants. Methods. Rabbits given VX-2 carcinoma liver implants (n = 8) were imaged before and after the intravenous (IV) administration of 0.04 mmol/kg Mn-mesoporphyrin. MR images were correlated with gross-specimen cross-sections. The distribution of Mn in various tissues following IV administration of 0.04 mmol/kg Mn-mesoporphyrin was determined using atomic absorption analysis. A standard panel of serum chemistries was followed over 7 days in six rabbits following this same dose of Mn-mesoporphyrin and compared with chemistries from two control rabbits. Results. IV administration of 0.04 mmol/kg (25 mg/kg) Mn-mesoporphyrin resulted in improvement of tumor-to-liver contrast, with enhancement of normal liver (99.7 ± 14.7%) and the gallbladder (442 ± 116%), but not VX-2 tumor tissue (14.8 ± 13.9%), (n = 8, p = .05). Analysis of tissue Mn levels 100 min after IV Mn-mesoporphyrin injection demonstrated preferential distribution of Mn to normal liver tissue (57.8 ± 15.3 μg Mn/g) compared with VX-2 tumor (4.28 ± 1.48 μg Mn/g). No significant change was found in the serum chemistries of six normal rabbits over a 7-day period after the IV administration of 0.04 mmol/kg Mn-mesoporphyrin. Conclusion. IV Mn-mesoporphyrin improved lesion-to-liver contrast because of preferential distribution of Mn mesoporphyrin to normal liver parenchyma and bile.

Sequential MR imaging with gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) and sequential measurements of plasma Gd-DTPA concentration by inductively coupled plasma atomic emission spectroscopy (ICP-AES) were used to estimate the blood-to-tissue transport coefficient (Ki) in the 36B-10 rat glioma model. For these measurements, tissue Gd-DTPA concentration was estimated from tumor enhancement by correlation with calibration measurements obtained by ICP-AES analysis of tumor tissue. The 14 animals for which Ki, was calculated can be grouped into those imaged at 11 days following tumor implantation, at 13-18 days, and at 20 days. The mean (+SEM) Ki values for these groups were 1.1 + 0.24, 9.2 + 0.8, and 13.4 + 1.7 ml/kg-min, respectively. These results correspond well with published data obtained by quantitative autoradiography. It is concluded that frequent sequential imaging and a graphical approach to Ki, calculation are promising methods for determining the blood-to-tissue transport coefficient noninvasively by contrastenhanced MRI.

The interest in tissue distribution of variously labeled or otherwise detectable natural and synthetic porphyrins and porphyrin derivatives dates back well over 60 years. Although a considerable interest in fluorescent turnor localization and therapy dominates the history of porphyrin biodistribution studies, many investigators have evaluated the diagnostic and therapeutic characteristics of porphyrins with radioactive, radiopaque, and paramagnetic qualities. In this paper, a review of the use of porphyrins as nuclear medicine, X-ray, and NMR contrast agents is presented. © 1991 Academic Press, Inc.