Diagnostic Architectural and Dynamic Features at Breast MR Imaging: Multicenter Study

PURPOSE

To prospectively determine the prevalence and predictive value of three-dimensional (3D) and dynamic breast magnetic resonance (MR) imaging and contrast material kinetic features alone and as part of predictive diagnostic models.

MATERIALS AND METHODS

The study protocol was approved by the institutional review board or ethics committees of all participating institutions, and informed consent was obtained from all participants. Although study data collection was performed before HIPAA went into effect, standards that would be compliant with HIPAA were adhered to. Data from the International Breast MR Consortium trial 6883 were used in the analysis. Women underwent 3D (minimum spatial resolution, 0.7 x 1.4 x 3 mm; minimal temporal resolution, 4 minutes) and dynamic two-dimensional (temporal resolution, 15 seconds) MR imaging examinations. Readers rated enhancement shape, enhancement distribution, border architecture, enhancement intensity, presence of rim enhancement or internal septations, and the shape of the contrast material kinetic curve. Regression was performed for each feature individually and after adjustment for associated mammographic findings. Multivariate models were also constructed from multiple architectural and dynamic features. Areas under the receiver operating characteristic curve (Az values) were estimated for all models.

RESULTS

There were 995 lesions in 854 women (mean age, 53 years +/- 12 [standard deviation]; range, 18-80 years) for whom pathology data were available. The absence of enhancement was associated with an 88% negative predictive value for cancer. Qualitative characterization of the dynamic enhancement pattern was associated with an Az value of 0.66 across all lesion architectures. Focal mass margins (Az = 0.76) and signal intensity (Az = 0.70) were highly predictive imaging features. Multivariate models were constructed with an Az value of 0.880.

CONCLUSION

Architectural and dynamic features are important in breast MR imaging interpretation. Multivariate models involving feature assessment have a diagnostic accuracy superior to that of qualitative characterization of the dynamic enhancement pattern.

Added cancer yield of MRI in screening the contralateral breast of women recently diagnosed with breast cancer: results from the International Breast Magnetic Resonance Consortium (IBMC) trial

OBJECTIVE

To estimate the added cancer yield of magnetic resonance imaging (MRI) over mammography in the contralateral breast of patients with a recent diagnosis of breast cancer.

METHODS

We conducted a prospective, international study of mammography and MRI in women with a recent diagnosis of unilateral breast cancer. Each subject received a mammogram, clinical breast exam (CBE), and MRI of the unaffected breast within a 90 day time period. Definitive diagnosis of suspicious findings was determined through biopsy and central pathology review.

RESULTS

Of the 103 eligible women included in study analyses, MRI detected 4 cancers in the contralateral breast while mammography detected none. MRI resulted in 12% (95% CI, 6%-20%) of women recommended for biopsy and 10% of women undergoing additional biopsy. The added cancer yield of MRI was 4% (95% CI, 1%-10%) and the positive predictive value of an abnormal MRI was 33% (95% CI, 10%-65%). Forty percent (4/10) of the biopsies performed based on the MRI recommendation were positive for malignancy.

CONCLUSION

In women with a recent breast cancer diagnosis, approximately 4% will have an otherwise occult invasive breast cancer detected in the opposite breast by MRI alone.

Screening women at high risk for breast cancer with mammography and magnetic resonance imaging

BACKGROUND

The authors compared the performance of screening mammography versus magnetic resonance imaging (MRI) in women at genetically high risk for breast cancer.

METHODS

The authors conducted an international prospective study of screening mammography and MRI in asymptomatic, genetically high-risk women age >/= 25 years. Women with a history of breast cancer were eligible for a contralateral screening if they had been diagnosed within 5 years or a bilateral screening if they had been diagnosed > 5 years previously. All examinations (MRI, mammography, and clinical breast examination [CBE]) were performed within 90 days of each other.

RESULTS

In total, 390 eligible women were enrolled by 13 sites, and 367 women completed all study examinations. Imaging evaluations recommended 38 biopsies, and 27 biopsies were performed, resulting in 4 cancers diagnosed for an overall 1.1% cancer yield (95% confidence interval [95%CI], 0.3-2.8%). MRI detected all four cancers, whereas mammography detected one cancer. The diagnostic yield of mammography was 0.3% (95%CI, 0.01-1.5%). The yield of cancer by MRI alone was 0.8% (95%CI, - 0.3-2.0%). The biopsy recommendation rates for MRI and mammography were 8.5% (95%CI, 5.8-11.8%) and 2.2% (95%CI, 0.1-4.3%).

CONCLUSIONS

Screening MRI in high-risk women was capable of detecting mammographically and clinically occult breast cancer. Screening MRI resulted in 22 of 367 of women (6%) who had negative mammogram and negative CBE examinations undergoing biopsy, resulting in 3 additional cancers detected. MRI also resulted in 19 (5%) false-positive outcomes, which resulted in benign biopsies.

Pseudoaneurysm

Percutaneous large core needle biopsy of the breast is recognized as an important tool in the current management of breast disease. Ths technique is safe, accurate, and has a very low complication rate. We present a rare complication of a pseudoaneurysm after large core needle biopsy of the breast, diagnosed by means of ultrasound and color Doppler exam-inatin. Pathophysilogic characteristics, diag-nosis, treatment options, and potential pre-vention of this complication are discussed.

Effect of the number of core biopsies of the prostate on predicting Gleason score of prostate cancer

PURPOSE

We determined the effect of the number of core biopsies of the prostate on predicting the Gleason score of the prostatectomy specimen.

MATERIALS AND METHODS

The Gleason scores from 124 radical prostatectomy specimens were compared to those from preoperative core needle biopsies of the prostate. The number of cores obtained and tumor stage were compared regarding agreement in prostate cancer score.

RESULTS

Four to 6 core biopsies yielded the best results, with agreement within 1 Gleason score in 75% of the cases. Further increases in the number of core biopsies did not improve results. Additionally, 37% of the well differentiated tumors on core biopsy were stage C.

CONCLUSIONS

Gleason score from the core biopsy has limitations in respect to predicting prostatectomy tumor score and stage and, therefore, it is problematic for use in therapeutic decision making.

Solid breast nodules: use of sonography to distinguish between benign and malignant lesions

PURPOSE

To determine whether sonography could help accurately distinguish benign solid breast nodules from indeterminate or malignant nodules and whether this distinction could be definite enough to obviate biopsy.

MATERIALS AND METHODS

Seven hundred fifty sonographically solid breast nodules were prospectively classified as benign, indeterminate, or malignant. Benign nodules had no malignant characteristics and had either intense homogeneous hyperechogenicity or a thin echogenic pseudocapsule with an ellipsoid shape or fewer than four gentle lobulations. Sonographic classifications were compared with biopsy results. The sensitivity, specificity, and negative and positive predictive values of the classifications were calculated.

RESULTS

Benign histologic features were found in 625 (83%) lesions; malignant histologic features, in 125 (17%). Of benign lesions, 424 had been prospectively classified as benign. Two lesions classified as benign were found to be malignant at biopsy. Thus, the classification scheme had a negative predictive value of 99.5%. Of 125 malignant lesions, 123 were correctly classified as indeterminate or malignant (98.4% sensitivity).

CONCLUSION

Sonography can be used to accurately classify some solid lesions as benign, allowing imaging follow-up rather than biopsy.

Liver volume assessment by conventional vs. helical CT

BACKGROUND

Accurate noninvasive measurement of the volume of the liver has many potential clinical applications and is an important element in the preoperative evaluation of the liver transplant recipient. Helical (or spiral) computed tomography (CT) has theoretical advantages over conventional CT in this application because the entire liver can be imaged in a single breath-hold, limiting inaccuracies related to patient motion and respiratory variation.

METHODS

We compared liver volumes measured by conventional CT and helical CT in 22 patients undergoing preoperative evaluation for liver transplantation.

RESULTS

The mean volume for helical CT is 1328 ml (SD 405) and conventional CT is 1323 ml (SD 417).

CONCLUSIONS

We found no significant difference between the helical CT and conventional CT volumes for each patient.

Magnetic resonance imaging of benign adnexal conditions

Magnetic resonance imaging can be used to demonstrate a variety of benign adnexal diseases. However, the real utility and efficacy of MR imaging in benign pelvic disease has not been investigated thoroughly. This is the challenge for future research. Presently, particularly in light of changes in the health care system, it is incumbent upon radiologists, gynecologists, and other clinicians to determine what additional information MR imaging will add to the diagnostic evaluation already completed before performing MR imaging. One must ask several questions. Will MR imaging provide additional information? Will that information affect care and treatment of the patient? Will the treatment be beneficial to the care of the patient? Will the patient agree to the management? Many times these questions are not asked. And if asked, the answers are unknown or under investigation. However, using one's best clinical judgment and armed with the knowledge at hand, if answers to the above questions are yes, then MR imaging may prove useful.

Sonographic Findings in an Infarcted Sigmoid Appendix Epiploica During Pregnancy

An infarcted sigmoid appendix epiploica in a pregnant patient with left lower quadrant pain was identified as a hypoechoic extrauterine mass on ultrasound examination. Ultrasound can help identify more common causes of pain in pregnancy, such as ectopic pregnancy, placental abruption, or degeneration of a leiomyoma. When these are excluded, rare causes of abdominal pain in the pregnant patient, including infarcted appendix epiploica, need to be considered.

Diagnosis of pneumoperitoneum: abdominal CT vs. upright chest film

To compare the sensitivity of CT with upright chest radiography for the detection of free intraperitoneal air, we compared the results of these examinations performed on trauma patients who had introduction of intraperitoneal air from diagnostic peritoneal lavage (DPL). Thirteen patients were studied by abdominal CT within 24 h after DPL. Upright chest radiography was performed prior to abdominal CT or less than 4 h after abdominal CT. All patients demonstrated free air on abdominal CT. Only 5 of 13 (38%) patients demonstrated free air on plain radiography. The amount of free air demonstrated on CT was quantified into three groups. Upright chest radiography in the minimal group (less than three 1 mm pockets of air) was totally insensitive (0 of 2) in detecting free air. Upright chest radiography in the moderate group (greater than three 1 mm pockets, but less than 13 mm diameter collection of air) was 33% sensitive (3 of 9). Upright chest radiography in the large group (greater than 13 mm collection of air) was 100% sensitive (2 of 2). Abdominal CT is clearly superior to upright chest radiography in demonstrating free intraperitoneal air in this clinical setting.

CT of melanoma liver metastases: is the examination without contrast media superfluous?

The current method of evaluating hypervascular liver metastases with CT includes both contrast enhanced and unenhanced studies. The necessity of performing both examinations for the detection of liver metastases in the workup of malignant melanoma has not been specifically addressed. This study evaluates potential additional information derived from an unenhanced examination of the liver. We studied 55 patients with malignant melanoma who had both contrast enhanced and unenhanced CT examinations performed during the workup and staging of their disease. Sixteen patients had 89 measurable liver lesions seen on enhanced CT. Three patients had liver lesions that were too numerous to accurately measure. Unenhanced CT demonstrated only 62% of the measurable lesions. All liver lesions seen on the unenhanced images were identified on the enhanced studies. Only one metastasis was found to be comparatively smaller on the enhanced examinations. The unenhanced examinations detected no additional lesions. It is reasonable to perform only an enhanced examination during the workup and staging of malignant melanoma liver metastases.

Comparison of orthoroentgenography and computed tomography in the measurement of limb-length discrepancy

To determine the most accurate roentgenographic technique for the measurement of limb-length discrepancy, the twenty lower extremities of ten cadavera were measured with use of both orthoroentgenograms and lateral scout computed-tomographic scanograms. The actual anatomical limb length also was measured, to serve as a control. The effects of flexion of the knee joint, use of an external fixator, cost and time of the examination, and exposure to radiation also were determined. No statistically significant difference in the measurements of the length of the femur was found between the two methods at neutral or at 15, 30, or 45 degrees of flexion of the knee. However, computed tomography was significantly more accurate than orthoroentgenography in the measurements of length of the tibia and of total length of the limb when the knee was flexed to 30 degrees or more (p less than 0.01). The placement of an Ilizarov fixator did not alter the results. The cost and time necessary to complete an examination were comparable for the two methods. However, computed tomography delivered only 20 per cent of the radiation needed for orthoroentgenography. Computed tomography is more accurate than orthoroentgenography for the measurement of limb-length discrepancy in patients who have a flexion deformity of the knee.

Popliteal artery entrapment: findings at MR imaging

Magnetic resonance (MR) imaging can noninvasively demonstrate the anatomic relationships between the popliteal artery and the muscles within the popliteal fossa, making it an ideal screening test for popliteal artery entrapment prior to angiography or surgery. The authors describe a patient with bilateral type II popliteal artery entrapment in whom the anomaly was diagnosed in the asymptomatic extremity with MR imaging.

Infection in utero: US findings in 19 cases

The results of antenatal sonographic studies of 19 fetuses with congenital infections were retrospectively reviewed by the authors. Recognizing the significance of these antenatal sonographic findings is important because in utero infections can have devastating effects on the developing fetus. An infectious viral agent was isolated in laboratory tests at birth in 11 patients, and the effects of a viral agent were proved clinically in eight. Antenatal sonography demonstrated abnormalities in 18 fetuses: Multiple organ systems were affected in 47%; intracranial abnormalities, cardiac abnormalities, and parenchymal calcifications occurred in 42%, 37%, and 32%, respectively; large placentas were seen in 32%; and the volume of amniotic fluid was decreased in 37% and increased in 37%. Sixty-three percent of fetuses were either aborted or died at birth; the 37% that lived were all developmentally impaired. On the basis of these sonographic, laboratory, and clinical findings, the authors conclude that when multiple organ system abnormalities are found at antenatal ultrasound, the presence of an in utero infection should be considered. The parents should be informed that there is a poor prognosis for any fetus demonstrating such abnormalities.

Bullet identification with radiography

The authors provide a simple radiographic method for estimating bullet weight and caliber of both deformed and undeformed bullets that enables accurate determination of caliber for the gamut of bullet shapes, with known degrees of confidence. The weight-determination procedure is based on the correlation between bullet cross-sectional area, as derived from three orthogonal radiographs, and bullet weight, as determined from a data base of the properties of 48 bullets removed from humans. Different equations were developed for bullets weighing 5.8 g or less, or more than 5.8 g. For relatively undeformed bullets an additional method calculated caliber directly from the diameter of the bullet body on radiographs. Both methods enabled correct prediction of the weight and caliber of the bullets; if one method could not be used, results of the other were reliable. Testimony based on these results has been accepted in a local police case and may meet requirements for testimony in U.S. court cases involving gunshots.

Prostatic comedocarcinoma: correlation of sonograms with pathologic specimens in three cases

A unique sonographic appearance that correlates with comedocarcinoma of the prostate is described. The hard-copy and videotaped transrectal sonograms obtained in 27 patients before radical prostatectomy were reviewed. In three, the sonograms had a distinctive appearance characterized by a hypoechoic lesion containing stippled areas of hyperechogenicity. This was not present in the other 24. The sonograms of all 27 patients were compared with whole-mount histopathologic sections of the radical prostatectomy specimens. This comparison showed that the distinctive sonographic abnormalities in these three patients were caused by foci of comedocarcinoma, an aggressive variant of prostatic carcinoma (Gleason pattern 5). In none of the other 24 patients were similar sonographic findings seen and none had comedocarcinoma at histopathologic examination. These findings suggest that a hypoechoic lesion containing diffuse, stippled echogenicity may be a sonographic sign of comedocarcinoma.

Liver-lesion tissue contrast on MR images: effect of iron oxide concentration and magnetic field strength

This study assessed the enhancement of liver-lesion contrast by using low levels of iron oxide contrast agent at four common magnetic resonance (MR) imaging field strengths: 0.15, 0.35, 0.5, and 1.5 T. Adenocarcinomas were percutaneously inserted into the livers of 15 rats. Iron oxide was given intravenously in concentrations of 0 (control group), 2.5, 5, 10, and 20 mumol/kg to three rats in each concentration group. All images were acquired between 1 and 24 hours after injection. Liver-lesion contrast ratios and contrast-to-noise ratios (C/Ns) were calculated. Results showed increased liver-lesion contrast and C/Ns with increased iron oxide concentration up to 10-20 mumol/kg at all four magnetic field strengths. At 0.15 T, iron oxide produced lower gains in tumor-liver contrast. At middle and high magnetic field strengths, liver-lesion contrast was similar for each level of iron oxide concentration, but C/Ns were markedly higher at 1.5 T than at middle field strength. Low levels of iron oxide contrast agent are effective at magnetic field strengths of 0.35 T and above, producing the greatest increase in C/N at middle field strengths.

Functional similarities of hepatic cystic and biliary epithelium: studies of fluid constituents and in vivo secretion in response to secretin

Hepatic cysts are a frequent manifestation of autosomal dominant polycystic kidney disease, but little is known about their functional characteristics. The goals of our study were to define the composition of hepatic cyst fluid and to determine whether hepatic cysts secrete in response to intravenously administered secretin. We percutaneously punctured five hepatic cysts and one proximal renal cyst from six subjects with autosomal dominant polycystic kidney disease and one solitary hepatic cyst from a subject without autosomal dominant polycystic kidney disease. Most fluids had an electrolyte composition similar to serum. Fluid from all hepatic cysts had glutamyltranspeptidase concentrations above those found in serum [( cyst]/[serum] = 4.93 +/- 5.92), contained secretory component (the epithelial receptor for polymeric IgA) and had glucose concentrations less than 15 mg/dl. Fluid from both hepatic and renal cysts of subjects with autosomal dominant polycystic kidney disease, but not from the subject with the solitary hepatic cyst, demonstrated extensive changes in the electrophoretic mobility of several serum proteins. Initial intracystic pressures ranged from 16 to 40 cm H2O, were reduced 57% to 97% after aspiration of a portion of cyst fluid and were held constant during the secretion study. Within 8 min of the intravenous administration of secretin, secretion of fluid increased in two of three hepatic cysts and in the renal cyst. The electrolyte composition of cyst fluids was not altered by secretin. These data suggest that hepatic cystic epithelium has functional characteristics of biliary epithelium and that secretion by both hepatic and renal cysts may be hormonally regulated.

Conservative management of cervical pregnancy with subsequent fertility

The reported incidence of cervical pregnancies with subsequent fertility is extremely low. We report a case managed conservatively that allowed for future fertility, and ultimately the delivery of a viable infant at term. The conservative management and a review of the literature are discussed.

Prostate cancer: comparison of pre-operative 0.35 T MRI with whole-mount histopathology

Magnetic resonance imaging of the prostate was performed in eight patients prior to radical prostatectomy. The results of the imaging studies were then directly compared to histopathologic findings from whole-mount histologic sections. Magnetic resonance imaging identified 82% of cancers greater than 5 mm in minimal diameter. Cancers were identified as areas of decreased signal intensity compared to the high signal intensity peripheral zone on long TR/TE sequences. Cancers were best detected when they involved the middle level of the gland and the posterior half of the prostate. Of the individual tumors identified by imaging, the amount of tumor involvement was underestimated by 37% and overestimated by 22% by MRI. We conclude that magnetic resonance imaging can identify prostate cancer, but has limitations as a screening modality and in accurately assessing the amount of involvement of the prostate gland by cancer.

Quantitative CT of the spine. Significance of intervertebral body variability

Quantitative CT of the spine has been used to predict and to identify a population at increased risk for fracture. This effort has been limited, in part, by the considerable range in normal values of mineral content. We studied the mineral contents of individual vertebral bodies to evaluate our empirical observation that mineral content changes from one vertebral body to the next and to assess the effect of this variability upon mineral content determination. Fifty-nine patients referred for the evaluation of osteoporosis were studied by single energy and dual energy quantitative CT. Variability among patients and fluctuations in the CT machine were corrected by a bone density phantom. Measured bone mineral contents were normalized by taking these variations into account. Analysis of covariance and t-tests indicated significant differences in the measured mineral contents from the T12 to the L3 vertebral bodies. Mean mineral contents for different vertebra were significantly different for both the single energy and dual energy methods, decreasing from T12 to L3. The measured mineral contents of the vertebral bodies within a given patient were highly correlated. The high correlation of the mineral contents of the vertebral bodies within a given patient strengthens the conclusions that individual vertebral content measurement is a valid predictor for the mineral content of vertebrae. The current method of averaging several vertebral bodies improves the reliability of an overall measurement of mineral content.

White matter lesions: role of spin density in MR imaging

To study the effect of hydrogen spin density (N[H]) on magnetic resonance (MR) image contrast in white matter disease of the brain, T1, T2, and N[H] values were determined for normal white matter and idiopathic white matter lesions (IWMLs) in 21 patients by using multiple spin-echo (SE) sequences. T1 values of IWMLs were significantly greater than those of normal white matter in all patients studied, and T2 values of IWMLs were significantly greater in 20 of 21 patients. N[H] values of IWMLs were greater in 20 of 21 patients, with statistically significant differences from those of normal white matter in 17 of those 20 patients. Averaged over all 21 patients studied, N[H] values of IWMLs were 20% higher than N[H] values of normal white matter. The effect of unequal N[H] values on contrast between IWMLs and normal tissues is to reduce contrast on short SE sequences with a short repetition time (TR) and a short echo time (TE), while enhancing contrast between IWMLs and normal tissues on long TR/TE SE sequences. Elevated N[H] values in IWMLs have a minimal effect on contrast in conventional inversion-recovery (IR) sequences but substantially enhance contrast between IWMLs and normal brain tissues in short inversion time IR sequences.

Vicarious excretion of water-soluble contrast media into the gallbladder in patients with normal serum creatinine

Ten patients with normal serum creatinine and no evidence of acute cholecystitis were found to have vicarious excretion of water-soluble contrast media into the gallbladder 20 minutes to 72 hours after injection. Eight of the ten had unilateral renal pathology. Two patients, however, had bilaterally normal kidneys. The patients had been injected with either diatrizoate, iothalamate, or iodamide. The mechanisms and pathophysiology of vicarious contrast excretion are discussed. The vicarious excretion of intravascular contrast in the gallbladder does not in itself indicate renal or hepatobiliary disease. Although commonly associated with unilateral renal pathology, vicarious gallbladder excretion of urographic contrast may be a normal variant in some patients.

Effect of phase-encoding direction upon magnetic resonance image quality of the heart

In order to optimize overall cardiac image quality on MR images experienced observers were asked to rank and rate MR images of the heart. The effect of phase-encoding direction and use of cardiac triggering with and without respiratory gating was examined in three orthogonal imaging planes. Results indicate that use of both respiratory and cardiac gating yields the best images. Adequate images of the heart can be obtained without respiratory gating. The quality of images of the heart can be optimized by proper selection of the direction of the phase-encoding gradient. These are improved by using horizontal phase encoding in the sagittal plane and vertical phase encoding in transverse and coronal planes.

Magnetic resonance imaging to evaluate patency of aortocoronary bypass grafts

To assess the efficacy of magnetic resonance (MR) imaging in evaluating graft patency after coronary bypass surgery, 20 patients who had prior surgery (average 5.5 years, range 1.5 to 14) and recent cardiac catheterization because of chest pain were studied. No patient had surgical intervention or change in symptoms in the time interval between catheterization and MR imaging. These 20 patients had a total of 47 grafts, defined as proximal anastomoses: 20 to the left anterior descending or diagonal artery (LAD), 13 to the left circumflex artery marginal branches (LCX), and 14 to the right coronary artery or posterior descending artery (RCA). The patients underwent cardiac and respiratory gated MR scans in a 0.5 tesla magnet with an echo time of 22 msec and two repetitions in a 128 X 256 matrix. In-plane resolution was 2.7 mm. Every patient had a scan in the transaxial plane and some underwent scanning in the sagittal and coronal planes as well. A graft was considered patent by MR when a signal-free lumen was visualized in an anatomic position consistent with that of a bypass graft, had a lumen larger than the native vessels, was seen on more than one slice, and was seen at a level higher than that of the native vessels. If a known graft was not seen it was considered occluded. The scans were interpreted by consensus of two physicians aware of the operative but not the cardiac catheterization data.(ABSTRACT TRUNCATED AT 250 WORDS)

Searching for lung nodules. A comparison of human performance with random and systematic scanning models

The contrast sensitivity of the retina is greatest in the center and decreases rapidly toward the periphery. Therefore, the detection of low-contrast lung nodules depends upon the manner in which the image is sampled by retinal receptors as eye fixations jump across the image during scanning. The scanning performance of two radiologists was compared with two computed models, a systematic and a random scanner. Although radiologists do not seem to have random scanning patterns, their coverage of the image was matched more closely by the random model. This suggests that radiologists employ a scanning strategy that is designed to cover the image of the lungs in a minimum time using the smallest possible visual field. The visual field size that is most effective in detecting nodules during search has a radius of 3.5 degrees visual angle. Nodule detection may be limited by basic neurologic constraints on human scanning performance.

Prior carotid surgery does not affect the reliability of landmarks for location of the internal jugular vein

Twenty-one volunteer subjects who had undergone prior carotid endarterectomy (CEA) agreed to an ultrasound study of the neck. The transducer was held as one would hold a cannulating needle and ultrasound images were obtained of the great vessels in the neck. Each of two cannulating techniques was simulated on each side of every patient's neck. Photographs of the ultrasound images were analyzed to score "hit" or "miss" for the internal jugular vein (IJV) and the carotid artery (CA), and to measure both the angle between these vessels and the distance from the skin to the IJV. In 11 subjects, the effect of a Valsalva maneuver on IJV width was also determined. Owing to bilateral CEA in 9 of the 21 subjects, there were 12 studies of nonsurgical sides (NSS) and 30 studies of surgical sides (SS). SS and NSS hit frequencies were statistically indistinguishable both for the IJV and the CA. In no photograph did the IJV lie medial to the CA. A Valsalva maneuver did not change IJV width on either the SS or the NSS. These data show that prior CEA does not affect the location of the IJV. Tissue alterations or adhesions may render actual IJV cannulation more difficult or risky. The data suggest but do not prove that prior CEA may not increase the incidence of CA puncture under clinical conditions.

Computed tomographic evaluation of the solitary nonpulmonic nodule

CT has demonstrated its usefulness in the evaluation of the known solitary pulmonic nodule, however its application to the solitary nonpulmonic nodule has not been emphasized. Three cases illustrate the applicability of CT in localization of a nodule. The importance of obtaining bone windows in these cases is stressed. When comparison plain films and routine techniques are unsatisfactory, CT is valuable in providing a noninvasive means of diagnosis and patient reassurance.

Postoperative peritoneal cysts

Peritoneal cysts are an infrequent postoperative complication. Few cases have been reported in the literature. This paper presents four cases seen after gynecologic operations. The cysts occurred 1.5 to 8 months postoperatively. The patients presented with pain and a large pelvic mass. No patient showed clinical or laboratory evidence of acute inflammation. Ovarian neoplasm was the leading diagnosis in three cases; the correct preoperative diagnosis of peritoneal cyst was made in only one case. Three patients were managed successfully with resection. One patient was treated with percutaneous drainage, though nine months was required for complete resolution. There were no recurrences at one-year follow-up.

Magnetic resonance imaging of avascular necrosis of the femoral head

This study investigates the role of magnetic resonance imaging (MR) in identifying avascular necrosis (AVN) of the femoral head and in monitoring its therapy. The detection of AVN, particularly in its early stages, is imperative to give therapeutic intervention the best opportunity for successful management. The results of magnetic resonance imaging are compared with those of the standard diagnostic modalities in evaluation of patients with the lesion. Examinations were performed at 0.12T with a repetition time (TR) of 143 ms and times to echo (TE's) of 10 or 20 ms. This study represents a retrospective review of 90 hips which were examined in 45 consecutive patients. Of these, 52 hips were biopsied as part of treatment. MR was shown to be sensitive in the detection of AVN. Comparison of MR with radionuclide imaging showed comparable sensitivity and specificity. MR was also noted to be sensitive in the detection of early AVN. Preliminary results suggest that MR can monitor treatment of the affected hip, and may even be able to predict patient response to therapy. Although further work is necessary to determine the role of MR in the evaluation of the patient presenting with hip pain, MR is a sensitive method in detecting AVN and in monitoring its course in patients suspected of having the disease.

Vascular occlusions detected by magnetic resonance imaging

Early experience with magnetic resonance imaging (MRI) indicates that it is well suited as a noninvasive vascular imaging modality. Blood flow at physiologic velocities results in a low signal within the vessel lumen and this property allows the separation of flowing blood from surrounding soft tissues. While flow effects, aneurysms, and mural lesions have been emphasized in the literature, vascular occlusions have received less attention. We evaluated 21 patients with documented venous or arterial occlusions on a 0.12-T developmental resistive unit. Venous occlusions caused by thrombus generally appeared as focal regions of increased signal. In 3 of 10 cases the venous thrombus itself could not be identified but the absence of a low-signal lumen in a normal location confirmed the impression of thrombus. In 2 of 17 venous occlusions a rim of low signal was noted around the thrombus. Venous collaterals were commonly seen. Tumor thrombus tended to have signal characteristics similar to the main bulk of the tumor from which it arose. There were four arterial occlusions including two cases of emboli, one arteriosclerotic occlusion, and one case of tumor invasion. Vascular calcifications, clearly evident on plain radiographs, were not seen on MRI. MRI appears to be a potentially useful noninvasive means of detecting vascular occlusions.

Controversies in the radiologic diagnosis of pelvic malignancies

Although vast differences exist among the many pelvic malignancies, several unifying concepts emerge from this discussion. First, there is a different role for diagnostic imaging for each type of pelvic malignancy. The radiologist should be aware that although the radiographic findings may be similar, the clinical impact varies greatly with a particular tumor. Second, although clinical staging is notoriously inaccurate, nevertheless diagnostic imaging techniques only improve upon but do not replace it because of false-positive and false-negative results. Third, because of the high false-negative rates of most of the modalities in use, negative studies do not in fact rule out the presence of disease. A surgical procedure may still be needed. Finally, several new techniques, including MRI and transrectal or transurethral ultrasound, may improve the accuracy rates. These developments will probably further enliven the controversies surrounding the radiologic evaluation of pelvic malignancies.

Nodule detection with and without a chest image

The detectability of nodules displayed on uniform backgrounds was compared with their detectability on chest images by using receiver operating characteristic (ROC) curves. The images were displayed using a digital television system. Two conditions, chest image and uniform background, were compared at three different levels of added random noise. The viewing conditions were made as similar as possible by setting the luminance of the uniform background equal to the luminance of the lung in the chest image. Nodule detectability was significantly lower for the chest image than for the uniform background at each level of added random noise. The anatomic structure of the chest image interferes with the structural integrity of the nodule image resulting in lower detection performance.

Nongated cardiac magnetic resonance imaging: preliminary experience at 0.12 T

Nongated cardiac magnetic resonance imaging (MRI) has been reported previously to be inadequate for obtaining diagnostic information. This study explored the role of pulse sequence in the degradation of the nongated cardiac image. Images of diagnostic quality were obtained by using single spin-echo sequences with a very short echo time (10-20 msec TE) on a 0.12-T developmental MR unit. Marked degradation of the image was noted with longer TEs, and it is concluded that the previous unfavorable reports using a nongated technique may have been due to the longer TEs used in other units. Short-TE technique was used to examine 34 patients with a variety of cardiac diseases. Eleven patients had ventricular aneurysms. These cases showed thinning of the myocardium, and four of them showed increased signal within the aneurysm, perhaps related to regionally slower blood flow. Twenty patients had enlargement of one or more cardiac chambers. Three of these patients had thrombus within an enlarged chamber, which was readily identified on MRI. Twelve patients had left ventricular hypertrophy that was concentric in 11. One patient demonstrated asymmetric septal hypertrophy. All four pericardial effusions were low in signal intensity, but this was related to the pulse sequence used. Six patients had extrinsic masses displacing the heart and distorting the chamber contour. One patient showed intracardiac invasion of tumor; this finding was not evident on the CT. One patient with ventricular septal defect (VSD) and corrected transposition was scanned. In addition to identifying the VSD and chamber hypertrophy, the malposition of the great vessels at the base of the heart was seen. Four postoperative patients were scanned; wire suture artifact did not preclude imaging. In conclusion, diagnostic information can be obtained from nongated cardiac images provided that the TE is very short (10-20 msec). Although quantitative functional data are not available from nongated images, qualitative and diagnostic information is possible and may suffice in certain circumstances.

Magnetic resonance imaging of postoperative patients with metallic implants

Magnetic resonance imaging (MRI) examinations were reviewed in 10 postsurgical patients with metallic implants in the abdomen or pelvis. MRI scans in these patients were free of the streak artifacts commonly encountered in computed tomography. This represents a significant advantage in diagnostic imaging in postsurgical patients, and it suggests that MRI may be a valuable technique in the postoperative assessment of patients with extensive abdominal surgical clips or metallic prostheses.

MR imaging of cerebral abnormalities in utero

In view of the lack of ionizing radiation, ability to image in a variety of planes, and high contrast resolution, magnetic resonance (MR) imaging may have a role in obstetrical management. Three fetuses with severe cerebral abnormalities were studied by MR in utero. The findings were correlated with ultrasound examinations and with autopsy results. Ventricular dilatation and progression of hydrocephalus were detected by MR. Although fetal motion may affect image quality, diagnostically useful images were obtained with imaging times of 2.5 min.

Nuclear magnetic resonance imaging in gynecology

Nuclear magnetic resonance proton imaging is a new imaging technique that holds promise for gynecologic diagnosis. Without the use of ionizing radiation, it provides images with excellent definition of the major pelvic organs. The extent and nature of disease are well demonstrated. In this report, an introduction to the principles of nuclear magnetic resonance imaging is given and several clinical examples that reveal the potential uses of nuclear magnetic resonance imaging in the female pelvis are shown.

CT imaging of the unusually shaped bladder

In the CT evaluation of a cystic pelvic mass it is important to identify the urinary bladder and assess its relationship to the mass. Although this is generally an easy task, we have encountered cases where delayed opacification of the bladder created diagnostic difficulties. Following intravenous contrast medium infusion, patients with normal renal function may have unopacified bladders due to (a) delayed transit from kidney to bladder and (b) rapid CT imaging of the bladder before opacification can occur. If one is aware of these problems, diagnostic dilemmas may be reduced by obtaining delayed scans of the pelvis or by obtaining postvoid films. Two cases are presented to illustrate these points.

MR imaging of the mediastinum: a retrospective comparison with computed tomography

Magnetic resonance (MR) imaging of the mediastinum was performed with a 0.12 T resistive magnet and compared with the results of CT. On T1 weighted images with partial saturation technique, soft tissue masses, lymphadenopathy, lipomatosis, and vascular anatomy were comparable with MR and CT imaging in 19 of 30 patients (63.3%). In the remaining 11 patients only slight differences between the two modalities were observed. Our experience suggests that MR imaging at low field strength is equivalent to CT in the morphologic assessment of the mediastinum without the need for administration of intravenous contrast medium or exposure to ionizing radiation.

Magnetic resonance evaluation of hydronephrosis in the dog

The ability of magnetic resonance (MR) imaging to detect and distinguish various stages of obstruction in the canine kidney was investigated. MR images were obtained at acute, subacute, and chronic stages of experimentally produced hydronephrosis. The renal cortex was distinguished from the renal medulla in the normal dog and in the acute and subacute stages of hydronephrosis. T1 relaxation times of the renal cortex and medulla were measured in vitro in 14 normal and nine experimental animals. These values were used to compute the amount of tissue contrast between the cortex and medulla and were compared with the degree of corticomedullary differentiation seen in the image. A relationship was noted between increasing T1 values and increasing water content. Corticomedullary contrast decreased with obstruction. The variation in corticomedullary image contrast may be useful for assessing the duration of hydronephrosis.

NMR imaging of the abdomen at 0.12 T: initial clinical experience with a resistive magnet

Forty-five patients with a variety of abdominal abnormalities and five normal volunteers were imaged on a 0.12 T resistive nuclear magnetic resonance system. Scans were obtained with saturation-recovery technique and short repetition times. The images reflected both proton density and T1 information. A variety of neoplastic and nonneoplastic disease processes involving the abdomen were imaged. Results suggest that clinically useful images clearly may be obtained at 0.12 T. In addition, saturation-recovery imaging with short repetition rates can detect a wide range of abdominal abnormalities.

NMR imaging of the chest at 0.12 T: initial clinical experience with a resistive magnet

The chests of 40 subjects were imaged with an experimental nuclear magnetic resonance (NMR) imager operating at a magnetic field of 0.12 T. There were six normal volunteers and 34 patients with abnormalities affecting different areas, including the chest wall, pleura, hila, mediastinum, and lung parenchyma, and including benign and malignant processes. In this initial clinical experience, NMR imaging provided useful information on the presence and extent of disease by its ability to distinguish different tissues and by the excellent demonstration of vascular structures.

Fibrodysplasia ossificans progressiva

Three hundred fifty-three previously reported cases of fibrodysplasia ossificans progressiva were reviewed and six new cases were analyzed radiologically. Characteristic findings of fibrodysplasia ossificans progressiva were confirmed and radiographic signs of the disease were demonstrated, including medial cortical thickening of the proximal tibia, narrow lumbar spinal canal, accessory epiphysis of the second phalanx of the fifth finger, and decreased humeral/epicondylar angle.