Biomedical subjects

Donald G Mitchell

Publications and source records attributed to Donald G Mitchell.

At least 19 recordsLinked to original sources

PubMed2006

Early invasive cervical cancer: tumor delineation by magnetic resonance imaging, computed tomography, and clinical examination, verified by pathologic results, in the ACRIN 6651/GOG 183 Intergroup Study.

PURPOSE: To compare magnetic resonance imaging (MRI), computed tomography (CT), and clinical examination for delineating early cervical cancer and for measuring tumor size. PATIENTS AND METHODS: A 25-center study enrolled 208 patients with biopsy-proven invasive cervical cancer for MRI and CT before attempted curative radical hysterectomy. Each imaging study was interpreted prospectively by one onsite radiologist and retrospectively by four independent offsite radiologists, who were all blinded to surgical, histopathologic, and other imaging findings. Likelihood of cervical stromal and uterine body involvement was rated on a 5-point scale. Tumor size measurements were attempted in three axes. Surgical pathology was the standard of reference. RESULTS: Neither MRI nor CT was accurate for evaluating cervical stroma. For uterine body involvement, the area under the receiver operating characteristic curve was higher for MRI than for CT for both prospective (0.80 v 0.66, respectively; P = .01) and retrospective (0.68 v 0.57, respectively; P = .02) readings. Retrospective readers could measure diameter by CT in 35% to 73% of patients and by MRI in 79% to 94% of patients. Prospective readers had the highest Spearman correlation coefficient with pathologic measurement for MRI (r(s) = 0.54), followed by CT (r(s) = 0.45) and clinical examination (r(s) = 0.37; P < .0001 for all). Spearman correlation of multiobserver diameter measurements for MRI (r(s) = 0.58; P < .0001) was double that for CT (r(s) = 0.27; P = .03). CONCLUSION: In patients with cervical cancer, MRI is superior to CT and clinical examination for evaluating uterine body involvement and measuring tumor size, but no method was accurate for evaluating cervical stroma.

Adenocarcinoma↗

PubMed2006

Focal liver lesions: breathhold gradient- and spin-echo T2-weighted imaging for detection and characterization.

PURPOSE: To evaluate breathhold gradient- and spin-echo (GRASE) T2-weighted imaging for the detection and characterization of focal liver lesions. MATERIALS AND METHODS: Two GRASE sequences with different echo times (75 and 90 msec, GRASE75 and GRASE90) were compared with respiratory-triggered fast spin-echo (SE) and breathhold fast SE in 64 patients with 103 malignant and 51 benign lesions. Compared with respiratory-triggered and breathhold fast SE, GRASE reduced scan time by 77% to 82% and 21% to 27%, respectively. Two independent readers evaluated image quality and reviewed 504 liver segments on a segment-by-segment basis. Observer performance was evaluated with receiver operating characteristic (ROC) curve analysis. The signal-to-noise ratio (SNR) of liver and spleen, and lesion-to-liver contrast-to-noise ratio (CNR) were also measured. RESULTS: The overall quality of the GRASE images was higher than that of the respiratory-triggered and breathhold fast SE images, although signal inhomogeneities were more frequently observed with GRASE. No significant difference in the values of the area under the ROC curve (Az) for malignant lesion detection was found. The mean SNR and CNR were highest for respiratory-triggered fast SE. CONCLUSION: T2-weighted breathhold GRASE has the potential to provide faster liver imaging.

Adult↗

PubMed2006

Gradient- and spin-echo T2-weighted imaging for SPIO-enhanced detection and characterization of focal liver lesions.

PURPOSE: To evaluate superparamagnetic iron oxide (SPIO)-enhanced breathhold T2-weighted GRASE imaging in detection and characterization of focal liver lesions. MATERIALS AND METHODS: In 30 patients (including 20 with cirrhosis) with 39 malignant and 25 benign lesions, gradient- and spin-echo (GRASE) images with two echo times (75 and 90 msec; GRASE75 and GRASE90) were obtained prior to and following administration of SPIO, and compared with respiratory-triggered and breathhold fast spin-echo (RT-FSE and BH-FSE) images. Two readers evaluated image quality and reviewed 240 liver segments for sensitivity and specificity. Signal-to-noise ratio (SNR), and its reduction in liver and spleen after administration of SPIO, and lesion-to-liver contrast-to-noise ratio (CNR) were measured. RESULTS: Compared with RT-FSE and BH-FSE, GRASE reduced scan time by 77% to 82% and 21% to 27%, respectively. The image qualities with BH-FSE and GRASE75 were higher than with BH-FSE and GRASE90. BH-FSE showed higher specificity than RT-FSE and GRASE90, but otherwise there were no significant differences between pulse sequences for sensitivity or specificity. The mean SNR and CNR of the lesions with RT-FSE were significantly higher than with the other methods. SPIO-induced signal reduction of liver SNR was smallest with BH-FSE. CONCLUSION: GRASE is faster and more sensitive to SPIO than FSE, but its sensitivity and specificity were slightly inferior to those of BH-FSE. Image quality is a current limitation.

Adult↗

PubMed2006

Optimal TE for SPIO-enhanced gradient-recalled echo MRI for the detection of focal hepatic lesions.

OBJECTIVE: The objective of our study was to determine the optimal TE for superparamagnetic iron oxide (SPIO)-enhanced gradient-recalled echo (GRE) MRI for the detection of focal hepatic lesions. MATERIALS AND METHODS: Ferucarbotran-enhanced GRE sequences, performed on a 1.5-T MR system, were used to evaluate 131 lesions (38 hepatocellular carcinomas, 37 metastases, 21 hemangiomas, 7 cholangiocarcinomas, 15 cysts, and 13 miscellaneous lesions) at four different TEs: 9, 13.5, 18, and 22.5 milliseconds. The lesion-to-liver signal difference-to-noise ratio (SDNR) was compared among the four GRE sequences by paired Student's t tests and among lesion types by an independent samples Student's t test. The McNemar test was used to compare the sensitivity for the detection of focal hepatic lesions. Wilcoxon's signed rank test was used to compare the subjective lesion conspicuity. RESULTS: The SDNRs of lesions on GRE images obtained at a TE of 13.5 milliseconds (mean +/- SD, 60 +/- 24) were significantly (p < 0.001) higher than those at TEs of 9 (55 +/- 23), 18 (55 +/- 22), and 22.5 milliseconds (47 +/- 19). The SDNR was highest at a TE of 13.5 milliseconds for SPIO-uptake lesions and was comparable on images obtained with TEs of 18 and 13.5 milliseconds for non-SPIO-uptake lesions. The non-SPIO-uptake lesions showed a significantly higher SDNR than the SPIO-uptake lesions at a TE of 22.5 milliseconds (p = 0.007). The overall sensitivity for lesion detection was not significantly different among the four GRE sequences, and the subjective ratings of lesion conspicuity were comparable for images obtained using TEs of 8, 13.5, and 18 milliseconds, but the ratings of lesion conspicuity were significantly lower for images obtained using a TE of 22.5 milliseconds (p < 0.001). CONCLUSION: For ferucarbotran-enhanced MRI, lesion SDNR was highest on images obtained using a TE of 13.5 milliseconds, but the sensitivity and lesion conspicuity were comparable at TEs of 9 and 18 milliseconds. The SDNR of liver lesions varied according to the lesion's potential capability of taking up SPIO agents.

Adult↗

PubMed2006

ADC measurement of abdominal organs and lesions using parallel imaging technique.

OBJECTIVE: The purpose of our study was to assess the reliability and usefulness of parallel imaging for apparent diffusion coefficient (ADC) measurement of abdominal organs and lesions. MATERIALS AND METHODS: Single-shot spin-echo echo-planar diffusion-weighted MRI (TE = 66, b = 0, 600 s/mm2) was performed in phantom and clinical studies. The b value was set to minimize the effects of perfusion in tissue and to maintain signal-to-noise ratio. Bottle phantoms were scanned with and without parallel imaging and with various parallel imaging factors and at various positions to evaluate the effects of parallel imaging on ADCs. In 200 consecutive clinical patients (122 men and 78 women: mean age, 61.9 years), ADCs were calculated for liver (four segments), spleen, pancreas (head, body, tail), gallbladder, renal parenchyma, and back muscle, and then compared to evaluate the reliability of clinical ADC measurements with parallel imaging. ADCs were also calculated for diffuse diseases and focal lesions (94 malignant and 93 benign) of abdominal organs to evaluate the clinical usefulness of ADC. RESULTS: Location-dependent changes in water ADCs were minimal with parallel imaging factors first of 3, then of 4, and were small except for measurements at the image periphery. Acetone ADCs were saturated at 4.00 x 10(-3) mm2/s. Degraded image quality prevented ADC measurement of the left hepatic lobe and pancreas in 7-18 patients. There was no significant difference among ADCs of four liver segments (1.50 +/- 0.24 [SD] x 10(-3) mm2/s - 1.56 +/- 0.31 x 10(-3) mm2/s) and between ADCs of the right and left kidneys (2.65 +/- 0.30 x 10(-3) mm2/s, 2.59 +/- 0.33 x 10(-3) mm2/s). ADC of the pancreas tail (1.65 +/- 0.37 x 10(-3) mm2/s) was significantly lower than those of the head (1.81 +/- 0.40 x 10(-3) mm2/s) and body (1.81 +/- 0.41 x 10(-3) mm2/s) (p < 0.005). Renal ADCs were significantly lower in patients with renal failure (right: 2.15 +/- 0.30 x 10(-3) mm2/s; left: 2.11 +/- 0.25 x 10(-3) mm2/s) than in those without disease (right: 2.67 +/- 0.29 x 10(-3) mm2/s; left: 2.60 +/- 0.32 x 10(-3) mm2/s) (p < 0.005). ADC of pancreatic cancer was significantly higher than that of healthy pancreas (p < 0.05). ADC of renal angiomyolipoma was significantly lower than those of renal cell carcinoma and healthy renal parenchyma (p < 0.0005). CONCLUSION: Clinical ADC measurements of abdominal organs and lesions using parallel imaging appear to be reliable and useful, and the effect of parallel imaging on calculated values is considered to be minimal.

Adult↗

PubMed2005

Gadolinium-enhanced phase-contrast magnetic resonance portography.

PURPOSE: The purpose of this study was to investigate the effect and usefulness of gadolinium-chelated contrast medium in phase-contrast magnetic resonance (MR) portography. METHODS: Twenty-six patients (21 men, 5 women; aged 34 to 79 years, mean 62 years) underwent respiratory-triggered 3-dimensional phase-contrast portography before and after administration of gadolinium in a 1.5T MR unit. Coronal maximum intensity projection (MIP) images of the portal vein were reconstructed and compared to conventional arterial portograms regarding visualization. Signal-to-noise ratio (SNR) and portal vein-to-liver contrast-to-noise ratios (CNR) of main, right, right anterior, right posterior, left portal veins, and umbilical portion were measured on both non-enhanced and gadolinium-enhanced images and compared. RESULTS: Portal veins and branches were more clearly visualized on the gadolinium-enhanced than on the non-enhanced images. Compared to arterial portography, gadolinium-enhanced portography showed similar performances in visualization, except in the right posterior branch and left portal vein. No severe image degradation from respiration was experienced. SNR was significantly higher on the gadolinium-enhanced than on non-enhanced images except in the right anterior branch. CNR was significantly higher on the gadolinium-enhanced than on the non-enhanced images at all measured locations. CONCLUSIONS: Administration of gadolinium improves the SNR and CNR of phase-contrast portography and visualization of the portal vein. The phase-contrast technique with gadolinium enhancement can be used to evaluate the portal vein as a supplemental technique.

Adult↗

PubMed2005

Role of imaging in pretreatment evaluation of early invasive cervical cancer: results of the intergroup study American College of Radiology Imaging Network 6651-Gynecologic Oncology Group 183.

PURPOSE: To compare magnetic resonance imaging (MRI) and computed tomography (CT) with each other and to International Federation of Gynecology and Obstetrics (FIGO) clinical staging in the pretreatment evaluation of early invasive cervical cancer, using surgicopathologic findings as the reference standard. PATIENTS AND METHODS: This prospective multicenter clinical study was conducted by the American College of Radiology Imaging Network and the Gynecologic Oncology Group from March 2000 to November 2002; 25 United States health centers enrolled 208 consecutive patients with biopsy-confirmed cervical cancer of FIGO stage > or = IB who were scheduled for surgery based on clinical assessment. Patients underwent FIGO clinical staging, helical CT, and MRI. Surgicopathologic findings constituted the reference standard for statistical analysis. RESULTS: Complete data were available for 172 patients; surgicopathologic findings were consistent with FIGO stages IA to IIA in 76% and stage > or = IIB in 21%. For the detection of advanced stage (> or = IIB), sensitivity was poor for FIGO clinical staging (29%), CT (42%), and MRI (53%); specificity was 99% for FIGO clinical staging, 82% for CT, and 74% for MRI; and negative predictive value was 84% for FIGO clinical staging, 84% for CT, and 85% for MRI. MRI (area under the receiver operating characteristic curve [AUC], 0.88) was significantly better than CT (AUC, 0.73) for detecting cervical tumors (P = .014). For 85% of patients, FIGO clinical staging forms were submitted after MRI and/or CT was performed. CONCLUSION: CT and MRI performed similarly; both had lower staging accuracy than in prior single-institution studies. Accuracy of FIGO clinical staging was higher than previously reported. The temporal data suggest that FIGO clinical staging was influenced by CT and MRI findings.

Adenocarcinoma↗

PubMed2005

Utilization of diagnostic studies in the pretreatment evaluation of invasive cervical cancer in the United States: results of intergroup protocol ACRIN 6651/GOG 183.

PURPOSE: To review the current utilization of diagnostic tests prescribed by the International Federation of Gynecology and Obstetrics (FIGO) clinical staging guidelines in the pretreatment work-up of invasive cervical cancer, and to compare the data with those of previous patterns of care studies. PATIENTS AND METHODS: This interdisciplinary American College of Radiology Imaging Network/Gynecologic Oncology Group prospective clinical trial was conducted between March 1, 2000, and November 11, 2002. Twenty-five participating institutions, all from the United States, enrolled a total of 208 patients. Only patients scheduled for surgery with biopsy-confirmed cervical cancer of clinical FIGO stage IB or higher were eligible. The patterns of care data analysis was based on 197 patients who met all inclusion criteria. The conventional FIGO-recommended tests used for pre-enrollment FIGO clinical stage classification were at the discretion of the treating physician; overall frequency of use was tabulated for each test. RESULTS: Use of cystoscopy (8.1%) and sigmoidoscopy or proctoscopy (8.6%) was significantly lower than in 1988 to 1989 (P < .0001 in each instance). Intravenous urography was used in only 1% of patients as compared with 42% in 1988 to 1989 and 91% in 1983. No patient included in the data analysis had barium enema or lymphangiography. Only 26.9% of patients had examination under anesthesia for FIGO clinical staging. CONCLUSION: There is a large discrepancy between the diagnostic tests recommended by FIGO and the actual tests used for cervical cancer staging, suggesting a need to reassess the relevance of the FIGO guidelines to current clinical practice in the United States.

Adult↗

PubMed2005

Imaging and cancer: research strategy of the American College of Radiology Imaging Network.

The American College of Radiology Imaging Network (ACRIN) is a cooperative group funded by the National Cancer Institute and dedicated to developing and conducting clinical trials of diagnostic imaging and image-guided treatment technologies. ACRIN's six disease site committees are responsible for developing scientific strategies and resultant trials within the framework of ACRIN's five key hypotheses: (a) Screening and early detection with imaging can reduce cancer-specific mortality. (b) Less invasive image-guided therapeutic methods can reduce the mortality and morbidity associated with treating cancer. (c) Molecular-based physiologic and functional imaging can improve the diagnosis and staging of cancer, thus improving treatment. (d) Functional imaging can portray the effectiveness of treatment earlier and more accurately, thus reducing mortality and improving the likelihood of a cure. (e) Informatics and other "smart systems" can improve the evaluation of patients with cancer, thus leading to better and more effective treatments. This article details ACRIN's research strategy according to disease site through the year 2007.

Breast Neoplasms↗

PubMed2005

Functional MR cholangiography: diagnosis of functional abnormalities of the gallbladder and biliary tree.

OBJECTIVE: Our objective was to describe the technique and utility of functional MR cholangiography (fMRC) in the evaluation of the gallbladder and biliary tree. CONCLUSION: FMRC has the potential to provide a comprehensive examination for the anatomic and functional assessment of the gallbladder and biliary tree. Complex anatomic abnormalities and functional disorders can be shown by fMRC, including biliary obstruction and extravasation.

Biliary Tract↗

PubMed2004

Imaging diagnosis of cirrhosis and chronic hepatitis.

Cirrhosis is an end stage of chronic diffuse liver disease, characterized by irreversible hepatic fibrosis. Cirrhosis slowly progresses from chronic hepatitis to early cirrhosis and finally to advanced cirrhosis with the increasing risk of complications, and causes regional morphologic changes of the liver during the course of the disease, according to disease severity. MR imaging is better able to provide comprehensive information about cirrhosis or chronic hepatitis and their complications than any other imaging modality currently available. In this article, we reviewed the spectrum of imaging findings of cirrhosis and chronic hepatitis, including regional changes of hepatic morphology, several signs of early and advanced cirrhosis, nodular liver surface, hepatic iron deposition, regenerative nodules, and varices and portosystemic collaterals.

Hepatitis B, Chronic↗

PubMed2003

Suspected early or mild chronic pancreatitis: enhancement patterns on gadolinium chelate dynamic MRI. Magnetic resonance imaging.

PURPOSE: To assess whether measuring the pattern of pancreatic enhancement on gadolinium chelate dynamic magnetic resonance imaging (MRI) is helpful for diagnosis of suspected early or mild chronic pancreatitis. MATERIALS AND METHODS: In this retrospective study, 24 patients with suspected early or mild chronic pancreatitis, classified by imaging criteria of equivocal chronic pancreatitis (ultrasound, computed tomography [CT] or ERCP) grading, had dynamic MRI that included unenhanced, arterial dominant, early venous, and late venous phases of contrast enhancement. Twenty patients without pancreatic diseases also had the dynamic sequence as a control group. The signal intensity was measured at the pancreatic head, body, and tail on all phases, and for each, the signal intensity ratio (SIR, the signal intensity in postcontrast divided by that in precontrast) was calculated. Two radiologists independently reviewed the images of the patients with suspected early or mild chronic pancreatitis for pancreatic morphologic abnormalities without knowing the results of signal intensity measurements. RESULTS: On unenhanced images, there was no significant difference of signal intensity between control and pancreatitis groups (P < 0.05). In the pancreatitis group, but not in the control group, the unenhanced signal intensity of the pancreatic head and body were significantly higher than that of the tail (P < 0.05). In the control group, the greatest enhancement (highest SIR) after injection was in the arterial phase (1.89 +/- 0.31), significantly higher than that in the early venous phase (1.68 +/- 0.17, P < 0.01) and in the late venous phase (1.61 +/- 0.15, P < 0.001). The pancreatitis group, however, had an arterial phase SIR (1.65 +/- 0.23) that was significantly lower than its early venous phase SIR (1.75 +/- 0.22, P < 0.05) and lower than the arterial phase SIR of the control group (P < 0.01). The presence of an SIR less than 1.73 in the arterial phase and/or a delayed peak enhancement after contrast agent administration had a sensitivity and specificity of diagnosing early or mild chronic pancreatitis of 92% and 75%, respectively. This sensitivity was significantly higher than the sensitivity of 50% for diagnosis based on morphologic abnormalities (P < 0.05). CONCLUSION: Measuring pancreatic signal intensity on gadolinium chelate dynamic MRI is helpful for diagnosing early or mild chronic pancreatitis, especially before apparent pancreatic morphologic or signal intensity changes are present.

Adult↗

PubMed2003

Functional magnetic resonance cholangiography (fMRC) of the gallbladder and biliary tree with contrast-enhanced magnetic resonance cholangiography.

PURPOSE: To determine the diagnostic performance of functional magnetic resonance cholangiography (fMRC) for the evaluation of anatomic and functional biliary disorders. MATERIALS AND METHODS: At 1.5 T, 39 MR examinations with conventional MRC and mangafodipir trisodium-enhanced fMRC were retrospectively reviewed by three observers who recorded anatomic (duct dilation, stricture, filling defects) and functional (cholecystitis, obstruction) abnormalities in three modes: MRC alone, fMRC alone, and MRC and fMRC images together (combined-MRC). Performance was determined by comparing findings with each mode to findings of invasive cholangiography (IC) and surgery. RESULTS: Among 75 biliary segments (correlated with IC), the sensitivity/specificity for diagnosing dilation (N = 41) with MRC was 95%/97%; with fMRC, 90%/100%; with combined-MRC, 100%/97%. For stricture (N = 7), the sensitivity/specificity of MRC was 86%/98%; of fMRC, 43%/100%; of combined-MRC, 86%/100%. For filling defects (N = 9), the sensitivity/specificity of MRC was 91%/98%; of fMRC, 82%/100%; of combined-MRC, 91%/100%. For diagnosing obstruction (N = 9), the sensitivity/specificity of MRC, fMRC, and combined-MRC were 89%/100%, 100%/100%, and 100%/100%, respectively. For surgically proven cholecystitis (N = 13), positive predictive values for diagnosing acute/chronic cholecystitis for MRC were 33%/40%; for fMRC, 100%/50%; for combined-MRC, 100%/50%. CONCLUSION: Although single-shot fast spin echo (SSFSE)-MRC is valuable, the addition of fMRC increased diagnostic performance for functional biliary disorders.

Biliary Tract↗

PubMed2003

Right posterior hepatic notch sign: a simple diagnostic MR finding of cirrhosis.

PURPOSE: To determine the frequency of occurrence of the right posterior hepatic notch sign at MR imaging in patients with cirrhosis, and to assess its diagnostic capability of this sign as a simple diagnostic MR finding of cirrhosis. MATERIALS AND METHODS: This study population included 330 patients with pathologically proved cirrhosis (N = 202) or without clinical evidence of chronic liver diseases (N = 128, control group). MR images were qualitatively evaluated for the presence of the right posterior hepatic notch sign. This sign was considered present if there was a sharp notch in the right posterior surface of the liver. The presence of the expanded gallbladder fossa sign was also evaluated during the same reading session. RESULTS: The right posterior hepatic notch sign was observed in 145 of the 202 patients in the cirrhosis group, while this sign was seen in only two of the 128 patients in the control group (P < 0.0001). The sensitivity, specificity, and accuracy of this sign for the MR diagnosis of cirrhosis were 72%, 98%, and 82%, respectively. When the presence of either the expanded gallbladder fossa sign or the right posterior hepatic notch sign was considered for the MR diagnosis of cirrhosis, the sensitivity and accuracy increased to 86% and 89%, respectively. CONCLUSION: The right posterior hepatic notch sign can be used as a simple and highly specific sign of cirrhosis, if present. The diagnostic performance can be improved when the presence of either the expanded gallbladder fossa sign or the right posterior hepatic notch sign was considered.

Case-Control Studies↗

PubMed2003

MR cholangiopancreatography: evaluation of common pancreatic diseases.

In the evaluation of common pancreatic diseases, MRCP is a noninvasive alternative to ERCP. Ductal anatomy can be ascertained without risk of complications. MRCP is valuable in defining common anatomic variants, determining the state of the pancreatic duct in pancreatitis, and characterizing neoplasms, especially combined with other MR imaging sequences. With the advent of MRCP, techniques requiring endoscopy and percutaneous access are largely reserved for histologic diagnosis and treatment, or for cases in which MRCP fails to establish a diagnosis.

Cholangiopancreatography, Endoscopic Retrograde↗

PubMed2002

A nebula of gases from Io surrounding Jupiter.

Several planetary missions have reported the presence of substantial numbers of energetic ions and electrons surrounding Jupiter; relativistic electrons are observable up to several astronomical units (au) from the planet. A population of energetic (>30[?]keV) neutral particles also has been reported, but the instrumentation was not able to determine the mass or charge state of the particles, which were subsequently labelled energetic neutral atoms. Although images showing the presence of the trace element sodium were obtained, the source and identity of the neutral atoms---and their overall significance relative to the loss of charged particles from Jupiter's magnetosphere---were unknown. Here we report the discovery by the Cassini spacecraft of a fast (>103[?]km[?]s-1) and hot magnetospheric neutral wind extending more than 0.5[?]au from Jupiter, and the presence of energetic neutral atoms (both hot and cold) that have been accelerated by the electric field in the solar wind. We suggest that these atoms originate in volcanic gases from Io, undergo significant evolution through various electromagnetic interactions, escape Jupiter's magnetosphere and then populate the environment around the planet. Thus a 'nebula' is created that extends outwards over hundreds of jovian radii.

Journal Article↗

PubMed2002

Correlation of single-lumen silicone implant integrity with chemical shift artifact on T2-weighted magnetic resonance images.

PURPOSE: To correlate the integrity of single-lumen silicone gel implants with chemical shift artifact (CSA) associated with infolding of the elastomer shell. MATERIALS AND METHODS: The T2-weighted images of presurgical MRI examinations of 54 implants were retrospectively reviewed by two breast radiologists blinded to the operative and pathologic findings. CSA associated with intraluminal membranes was quantified by determining the fraction of membranes with it and categorized as minimal (0-1/3 of membranes involved), moderate (>1/3- <2/3), and marked (2/3 to all). CSA was qualified by noting whether CSA intensity of the membranes was less than or similar to that of blood vessels. The CSA was correlated with the surgical or pathology findings to judge integrity of the implant. RESULTS: Nineteen implants were intact, 35 were dysfunctional (gel leakage or rupture). Twenty-eight of 29 (97%) with a minimal fraction of membranes with CSA were dysfunctional; 17/21 (81%) with CSA associated with a marked fraction of membranes were intact (P < 0.001). All 28 implants with CSA intensity less than vessels were dysfunctional, 19/26 (73%) with CSA equal to vessels were intact (P < 0.001). All 25 implants with minimal CSA and intensity less than vessels were dysfunctional. Seventeen of 19 (89%) implants with CSA associated with a marked fraction of membranes and intensity equal to vessels were intact (P = 0.02). The magnetic resonance imaging (MRI) signs were combined with strong CSA as a predictor of integrity, and 22 of 26 (85%) implants were correctly diagnosed, 4 dysfunctional and 18 intact (P < 0.0001). CONCLUSION: CSA correlates with integrity of silicone gel implants on T2-weighted images and can be used with other MRI signs to improve diagnosis.

Artifacts↗

PubMed2002

Ovarian veins: magnetic resonance imaging findings in an asymptomatic population.

PURPOSE: To evaluate the magnetic resonance (MR) venographic appearance of the ovarian veins in a healthy population, correlated with surgical findings. Our data can be used as a basis for comparison to patients with suspected pelvic congestion syndrome (PCS). MATERIALS AND METHODS: We retrospectively reviewed exams of 22 women who had MR angiography for potential renal donation evaluation (age range, 19.3-60.5 years; mean, 38 years). We evaluated the diameter of the ovarian veins on dynamic multiphasic postcontrast coronal images, the phase of contrast appearance in these veins, the apparent direction of flow, and the presence of ovarian or pelvic varices. Surgical correlation was obtained in 12 patients. Clinical charts were reviewed and patients were asked about symptoms of chronic pelvic pain and the number of their children. RESULTS: Of the 22 exams, 21 left gonadal veins were identified. Passive reflux from the left renal vein into the left gonadal vein was suggested in eight exams (38%). These veins had a mean diameter of 6.4 +/- 1.6 mm, significantly larger than 4.5 +/- 1.3 mm for the other 13 left gonadal veins without reflux (P < 0.005). The right gonadal vein was identified in 8 of 22 women, with a mean diameter of 4.4 +/- 0.5 mm. No patient reported symptoms of chronic pelvic pain. CONCLUSION: Passive reflux from the left renal vein to the left gonadal vein can occur in asymptomatic women. Diagnosis of PCS depends heavily on appropriate clinical history.

Adult↗