Images in clinical medicine. Mammographically occult breast cancer.
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Breast Neoplasms↗
Biomedical subjects
B L Daniel
Publications and source records attributed to B L Daniel.
Radiofrequency ablation of breast cancer: first report of an emerging technology.
HYPOTHESIS: Radiofrequency (RF) energy applied to breast cancers will result in cancer cell death. DESIGN: Prospective nonrandomized interventional trial. SETTING: A university hospital tertiary care center. PATIENTS: Five women with locally advanced invasive breast cancer, aged 38 to 66 years, who were undergoing surgical resection of their tumor. One patient underwent preoperative chemotherapy and radiation therapy, 3 patients received preoperative chemotherapy, and 1 had no preoperative therapy. All patients completed the study. INTERVENTIONS: While patients were under general anesthesia and just before surgical resection, a 15-gauge insulated multiple-needle electrode was inserted into the tumor under sonographic guidance. Radiofrequency energy was applied at a low power by a preset protocol for a period of up to 30 minutes. Only a portion of the tumor was treated to evaluate the zone of RF ablation and the margin between ablated and nonablated tissue. Immediately after RF ablation, the tumor was surgically resected (4 mastectomies, 1 lumpectomy). Pathologic analysis included hematoxylin-eosin staining and enzyme histochemical analysis of cell viability with nicotinamide adenine dinucleotide-diaphorase (NADH-diaphorase) staining of snap-frozen tissue to assess immediate cell death. MAIN OUTCOME MEASURE: Cancer cell death as visualized on hematoxylin-eosin-stained paraffin section and NADH-diaphorase cell viability stains. RESULTS: There was evidence of cell death in all patients. Hematoxylin-eosin staining showed complete cell death in 2 patients. In 3 patients there was a heterogeneous pattern of necrotic and normal-appearing cells within the ablated tissue. The ablated zone extended around the RF electrode for a diameter of 0.8 to 1.8 cm. NADH-diaphorase cell viability stains of the ablated tissue showed complete cell death in 4 patients. The fifth patient had a single focus of viable cells (<1 mm) partially lining a cyst. There were no perioperative complications related to RF ablation. CONCLUSIONS: Intraoperative RF ablation results in invasive breast cancer cell death. Based on this initial report of the use of RF ablation in breast cancer, this technique merits further investigation as a percutaneous minimally invasive modality for the local treatment of breast cancer.
Adult↗
Differentiation of hepatic malignancies from hemangiomas and cysts by T2 relaxation times: early experience with multiply refocused four-echo imaging at 1.5 T.
The purpose of this study was to examine hepatic lesions with a sequence designed to yield improved T2 measurements and evaluate the clinical utility of these measurements in distinguishing malignant from benign disease. Using a modified Carr-Purcell sequence incorporating features designed to compensate for imperfections in the imaging system, including a train of refocusing pulses emitted in an MLEV pattern oriented in composite fashion along all three coordinate axes, and a single spatially selective pulse placed immediately before a spiral readout, 14 benign lesions and 13 malignant lesions were evaluated prospectively with a conventional 1.5 T imager. The maximum, minimum, and mean T2 values of malignant lesions, hemangiomas, and cysts exceeded corresponding published values from spin-echo and echoplanar studies. The mean T2 value of the malignant lesions differed significantly (P < 0.0001) from those of hemangiomas and cysts. All malignant lesions and all benign lesions were distinguishable by their T2 values, which had ranges of no greater than 118.6 msec and no less than 134.3 msec, respectively. This early experience suggests that improved T2 measurements can facilitate the differentiation of hepatic malignancies from hemangiomas and cysts.
Carcinoma, Hepatocellular↗
Management of biopsy needle artifacts: techniques for RF-refocused MRI.
Several methods were investigated to improve the depiction of biopsy needles in radiofrequency (RF)-refocused magnetic resonance imaging. Distortion correction is performed by the use of view angle tilting (VAT): a gradient is employed on the slice-select axis during readout. Needle conspicuity is increased by offsetting the gradient echo from the spin echo and by inverting the 90 degrees RF pulse slice-select gradient. VAT effectively re-registers in-plane shifts. Since this method changes the projection angle through the slice, some structures appear blurred, while other structures appear sharper. VAT does not correct errors in slice selection. Offsetting the spin echo from the gradient echo increases needle conspicuity but can result in a shift in the apparent location of the needle. Inverting the 90 degrees slice-select gradient effectively increases the needle conspicuity with no shift in the needle location. These methods provide an easy and interactive means to manipulate needle artifacts but should be used cautiously.
Artifacts↗
Joint motion in an open MR unit using MR tracking.
A system for active scan plane guidance during kinematic magnetic resonance (MR) examination of joint motion was developed utilizing an external tracking coil and MR tracking software. In a phantom study and during upright, weight-bearing, physiologic knee flexion, the external tracking coil maintained the scan plane through desired structures. Thus, MR tracking provides a robust method to guide the scan plane during MR imaging of active joint motion.
Biomechanical Phenomena↗
Magnetic resonance imaging of frozen tissues: temperature-dependent MR signal characteristics and relevance for MR monitoring of cryosurgery.
Previously, the magnetic resonance (MR) imaging appearance of frozen tissues created during cryosurgery has been described as a signal void. In this work, very short echo times (1.2 msec) allowed MR signals from frozen tissues to be measured at temperatures down to -35 degrees C. Ex vivo bovine liver, muscle, adipose tissue, and water were imaged at steady-state temperatures from -78 degrees to +6 degrees C. Signal intensity, T2*, and T1 were measured using gradient-echo imaging. Signal intensity and T2* decrease monotonically with temperature. In the future, these MR parameters may be useful for mapping temperatures during cryosurgery.
Adipose Tissue↗
Glenohumeral relationships during physiologic shoulder motion and stress testing: initial experience with open MR imaging and active imaging-plane registration.
PURPOSE: To test the hypotheses that open dynamic magnetic resonance (MR) imaging can (a) be used to evaluate and define normal shoulder motion in active joint motion and muscle contraction and (b) be used in conjunction with physical examination. MATERIALS AND METHODS: With an open-configuration, 0.5-T MR imaging system and active image-plane tracking, 10 shoulders were studied in five asymptomatic subjects to establish normal patterns of glenohumeral motion during abduction and adduction and internal and external rotation. Preliminary studies of physical examination during MR imaging, in which a physician examiner applied mechanical force to the humeral head, were also performed. RESULTS: During abduction and adduction and internal and external rotation maneuvers with active subjects muscle contraction, the humeral head remained precisely centered on the glenoid fossa in all asymptomatic subjects, which is in agreement with findings of previous radiographic studies. Application of force to the humeral head by an examiner was associated with as much as 6 mm of anterior translation and 13 mm of posterior translation. CONCLUSION: Dynamic MR imaging of the glenohumeral joint is possible over a wide range of physiologic motion in vertically open systems. Use of an MR tracking coil enabled accurate tracking of the anatomy of interest. These preliminary measurements of normal glenohumeral motion patterns begin to establish normal ranges of motion and constitute a necessary first step in characterizing pathologic motion in patients with common clinical problems such as instability and impingement.
Adult↗
Breast cancer: gadolinium-enhanced MR imaging with a 0.5-T open imager and three-point Dixon technique.
PURPOSE: To investigate the three-point Dixon technique as a method for obtaining fat-nulled images of contrast material-enhancing breast lesions with a 0.5-T open magnetic resonance (MR) imager. MATERIALS AND METHODS: Real and imaginary source images were obtained with an interleaved gradient-echo sequence with a repetition time of 550 msec and echo times of 12.8, 19.8, and 26.8 msec. Twenty-four to 28 sections were obtained in the sagittal plane with a 90 degrees flip angle, 256 x 192 matrix, 3-4.5-mm section thickness, and acquisition time of 10 minutes 54 seconds. A three-point Dixon reconstruction algorithm was used to generate water-specific, fat-specific, and combined images from the raw image data. Twelve breasts in 10 patients and one healthy volunteer were imaged. RESULTS: Three-point Dixon images were superior to extended two-point Dixon and fat-suppressed images and to images generated by means of subtraction of three-dimensional fast spoiled gradient-echo images obtained before contrast material injection from those obtained after. CONCLUSION: Three-point Dixon imaging provides a robust method for creating fat-nulled images of enhancing breast lesions in the 0.5-T open MR environment. Water-specific three-point Dixon images are successful in regions of B0 heterogeneity and are superior to fat-suppressed images. They are much less susceptible to motion artifact than are subtraction images.
Adult↗
Breast lesion localization: a freehand, interactive MR imaging-guided technique.
PURPOSE: To evaluate interactive magnetic resonance (MR) imaging-guided preoperative needle localization and hookwire placement in the noncompressed breast in patients in the prone position. MATERIALS AND METHODS: Nineteen MR imaging-guided breast lesion localization procedures were performed in 17 patients aged 38-70 years (mean age, 48 years) by using an open-platform breast coil in either a 1.5-T, closed-bore imager (n = 14) or a 0.5-T, open-bore imager (n = 5). Rapid imaging (fast spin-echo, water-selective fast spin-echo, or water-specific three-point Dixon gradient-echo) was alternated with freehand manipulation of an MR-compatible needle to achieve accurate needle placement. RESULTS: Up to three manipulations of the needle were required during an average of 9 minutes to reach the target lesion. MR imaging findings confirmed the final needle position within 9 mm of the target in all cases. The accuracy of 10 localizations was independently corroborated either at mammography or at ultrasonography. Nine lesions were visible on MR images only. CONCLUSION: Interactive MR imaging-guided, freehand needle localization is simple, accurate, and requires no special stereotactic equipment. Lesions throughout the breast, including those in the anterior part of the breast and those near the chest wall, which can be inaccessible with standard grid or compression-plate techniques, can be localized. A variety of needle trajectories in addition to the horizontal path are possible, including circumareolar approaches and tangential needle paths designed to avoid puncture of implants.
Adult↗
Breast disease: dynamic spiral MR imaging.
PURPOSE: To compare various subjective, empiric, and pharmacokinetic methods for interpreting findings at dynamic magnetic resonance (MR) imaging of the breast. MATERIALS AND METHODS: Dynamic spiral breast MR imaging was performed in 52 women suspected of having or with known breast disease. Gadolinium-enhanced images were obtained at 12 locations through the whole breast every 7.8 seconds for 8.5 minutes after bolus injection of contrast material. Time-signal intensity curves from regions of interest corresponding to 57 pathologically proved lesions were analyzed by means of a two-compartment pharmacokinetic model, and the diagnostic performance of various parameters was analyzed. RESULTS: Findings included invasive carcinoma in 17 patients, isolated ductal carcinoma in situ (DCIS) in six, and benign lesions in 34. Although some overlap between carcinomas and benign diagnoses was noted for all parameters, receiver operating characteristic analysis indicated that the exchange rate constant had the greatest overall ability to discriminate benign and malignant disease. The elimination rate constant and washout were the most specific parameters. The exchange rate constant, wash-in, and extrapolation point were the most sensitive parameters. DCIS was not consistently distinguished from benign disease with any method. CONCLUSION: Dynamic spiral breast MR imaging proved an excellent method with which to collect contrast enhancement data rapidly enough that accurate comparisons can be made between many analytic methods.
Breast↗
Interactive MR-guided, 14-gauge core-needle biopsy of enhancing lesions in a breast phantom mode.
RATIONALE AND OBJECTIVES: The authors attempted to determine the accuracy of magnetic resonance (MR) imaging-guided core-needle biopsy performed with a titanium biopsy needle in a breast phantom. MATERIALS AND METHODS: Eight 6-7-mm lesions were created at random positions in a lard breast phantom. Each 0.2-mL lesion contained 0.118 mg of gadopentetate dimeglumine, 0.0025 mL of methylene blue dye, and 23.8 mg of gelatin. Rapid fast spin-echo MR imaging was used to guide placement of a 14-gauge titanium core-biopsy needle. A 1.5-T MR imager was used with an open-platform phased-array breast coil. RESULTS: Visualization of blue dye in core specimens confirmed successful biopsy in 16 of 16 attempts. One (n = 13) or two (n = 3) passes through the "skin" of the phantom were necessary for biopsy. The needle trajectory was adjusted less than three times for each pass through the "skin" in 15 of 16 biopsies. Cores that contained lesion material were obtained in the first sample in 15 of 16 biopsies. On T1-weighted images, needles cast 7-mm-diameter artifacts. CONCLUSION: MR imaging can be used accurately to guide core-needle biopsy of 6-7-mm lesions in a breast phantom.
Biopsy, Needle↗
The hemodynamics of transjugular intrahepatic portosystemic shunts: investigations with Doppler sonography and development of an in vitro model.
RATIONALE AND OBJECTIVES: We evaluated Doppler sonography-based measurements of transjugular intrahepatic portosystemic shunt (TIPS) function and developed an in vitro model of normal TIPS hemodynamics. METHODS: We reviewed retrospectively the results of all trans-TIPS manometries (N = 116) performed during a 24-month period. Portosystemic pressure gradient was compared with peak stent velocity as measured by angle-corrected Doppler sonography. A flow phantom simulating TIPS was created using 8-, 10-, and 12-mm-diameter wire-mesh stents placed in cylindrical channels with lengths ranging from 3.4 to 6.0 cm. RESULTS: Among 50 trans-TIPS manometries with corresponding Doppler sonography performed on well-functioning shunts, measured portosystemic pressure gradient and peak velocity were not correlated (R2 = .014). On the basis of a regression of measurements in the flow phantom, pressure loss in a stented cylindrical channel was estimated as follows: delta p = rho.(0.145 -0.001.Rey + 0.816.L/D).(Vmean2/2), where rho is the fluid density, Rey is the Reynolds number, L is the channel length, D is the stent diameter, and Vmean is the time-averaged velocity within the stent. Predicted and measured pressure gradients were correlated (R2 = .91). CONCLUSION: Peak velocity in patients with a normally functioning TIPS does not predict the magnitude of the portosystemic pressure gradient.
Blood Flow Velocity↗
Schistosomiasis japonica in the Philippines: the long-term impact of population-based chemotherapy on infection, transmission, and morbidity.
The long-term impact of annual case-finding and chemotherapy with praziquantel on schistosomiasis japonica was examined in an 8-year longitudinal study in the Philippines. The prevalence, incidence, and intensity of infection and schistosome-induced hepatomegaly significantly decreased within 3-4 years of treatment and then stabilized despite continual population-based chemotherapy. Hepatomegaly rapidly developed in acutely infected persons, with 82% of subjects developing hepatic enlargement within 2 years of reinfection. These data suggest that abrupt discontinuation of current control measures in the Philippines may result in a rapid rebound in morbidity. Age-dependent acquired resistance to reinfection also developed in subjects chronically exposed to schistosomiasis japonica, suggesting that a vaccine may represent an alternative approach for control of this parasitic infection.
Adolescent↗
Point-counterpoint. Lymphography for staging lymphomas: is it still a useful procedure?
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Humans↗
The use of ultrasound mean acoustic attenuation to quantify bone formation during distraction osteogenesis performed by the Ilizarov method. Preliminary results in five dogs.
RATIONALE AND OBJECTIVES: Management of distraction during Ilizarov limb lengthening remains primarily clinical and empirical. Estimates of tissue acoustic attenuation were evaluated for their ability to quantify bone formation within the distraction gap. METHODS: Five dogs had tibias lengthened by the method of Ilizarov. Mean acoustic attenuation measurements at multiple positions across the distraction gap were compared with corresponding x-ray computed tomography attenuation measurements. RESULTS: Computed tomography and ultrasound attenuation displayed similar quantitative behavior across the gap. Linear correlation between them ranged from R2 = .878 to R2 = .131. Fibrous interzone width estimates based on computed tomography and ultrasound attenuation measurements were correlated, based on our preliminary data with R2 = .519. These estimates are independent of the width of distraction. CONCLUSIONS: Ultrasound parallels computed tomography as a measure of bone formation within the distraction gap. Future studies are needed to improve acoustic attenuation data acquisition techniques and to evaluate their potential as a tool for optimizing early distraction rates in patients at risk for rate-related complications.
Acoustics↗
Bone scintigraphy in blastomycotic osteomyelitis.
A case of disseminated North American blastomycosis is described in which the full extent of the multifocal osteomyelitis was depicted by Tc-99m MDP scintigraphy. Skeletal involvement by this disease is not uncommon, yet the utility of bone scintigraphy has not been reported. The efficacy with which the whole body may be examined makes this technique especially appropriate for a hematogenously disseminated and often multifocal form of osteomyelitis where radiographically occult and asymptomatic lesions may be present.
Blastomycosis↗
Child growth and schistosomiasis japonica in northeastern Leyte, the Philippines: cross-sectional results.
The association between schistosomiasis japonica and child growth was studied cross-sectionally in 1,561 males and females aged 4-19.9 years residing in an endemic region of northeastern Leyte, The Philippines. Stature, weight, upper arm muscle area, and sum of triceps and subscapular skinfold thicknesses were measured and related to presence of Schistosoma japonicum eggs in Kato stool smears and to the intensity of infection assessed by quantitative egg count. The presence of hookworm, ascaris, and trichuris eggs was also measured. Multivariable models were used to control for the effects of age, age2, and polyparasitism on growth. The prevalence of schistosomiasis was 31% in males and 22% in females, with the maximum prevalence in adolescence. In 8-19-year-old subjects, the intensity of schistosomiasis japonica was significantly related in males to reduced arm muscle area and sum of skinfolds (both P less than 0.01) and in females to reduced stature, weight, arm muscle area, and sum of skinfolds (all P less than 0.01). The greatest age-specific differences were during adolescence in both males and females. The growth retarding effects of intensity of schistosomiasis japonica were independent of the influence of other parasites, notably hookworm. Due to the magnitude of the schistosomiasis-associated growth differences in adolescence, adult body size, function and productivity may be affected.
Adipose Tissue↗
Diagnostic yield of MR-guided liver biopsies compared with CT- and US-guided liver biopsies.
PURPOSE: To compare diagnostic yield and complication rates of magnetic resonance (MR)-guided versus computed tomography (CT)- and ultrasound (US)-guided liver biopsies. MATERIALS AND METHODS: MR-, CT-, and US-guided liver biopsies performed between 9/96 and 9/98 were compared. Sixty patients (21 men and 39 women, mean age 60 years) underwent MR-guided biopsy of liver lesions. Thirty patients (16 men and 14 women, mean age 59 years) underwent CT-guided biopsy. Eighteen patients (seven men and 11 women, mean age 50 years) underwent US-guided biopsy. MR procedures were performed in an open-configuration 0.5-T Signa SP MR unit. Lesion localization used standard T1 and T2 sequences, whereas biopsies were performed with multiplanar spoiled gradient recalled echo and fast gradient recalled echo sequences. A coaxial system with an MR-compatible 18-gauge stabilizing needle and a 21-gauge aspiration needle was used to obtain all samples. In CT and US procedures, a 19-gauge stabilizing needle and a 21-gauge aspiration or a 20-gauge core biopsy needle were used. A cytotechnologist was present to determine the adequacy of samples. RESULTS: MR had a diagnostic yield of 61%. CT and US had diagnostic yields of 67% and 61%, respectively. No serious complications were reported for MR and US procedures. Two CT biopsies resulted in postprocedural hemorrhage. One patient required surgical exploration and died. CONCLUSIONS: MR-guided biopsy of liver lesions with use of a 0.5-T open-configuration magnet is safe and accurate when compared with CT and US. No statistical difference was observed between the diagnostic yield of biopsies performed with MR, CT, and US guidance. MR enabled biopsy of a number of lesions in the hepatic dome and lesions with low contrast, which would normally be difficult to sample safely with use of CT or US.
Biopsy, Needle↗