MR imaging of edema accompanying benign and malignant bone tumors

To evaluate the incidence, quantity, and presentation of intra- and extraosseous edema accompanying benign and malignant primary bone lesions, the magnetic resonance (MR) studies of 63 consecutive patients with histologically proven primary bone tumors were reviewed. MR scans were assessed for the presence and quantity of marrow and soft tissue edema and correlated with peroperative findings, resected specimens and follow-up data. The signal intensity and enhancement of tumor and edema prior to and after intravenous administration (if any) of gadolinium-labeled diethylene triamine pentaacetate (Gd-DTPA) was analyzed. Marrow edema was encountered adjacent to 8 of 39 malignant tumors and 14 of 24 benign lesions. Soft tissue edema was found accompanying 28 of 39 malignancies and 10 of 24 benign disorders. On unenhanced T1-weighted MR images tumor and edema were difficult to differentiate. Tumor inhomogeneity made this differentiation easier on T2-weighted sequences. In 36 patients the contrast medium Gd-DTPA was used. Edema was present in 27 of these patients and the respective enhancement of tumor and edema could be compared. Edema always enhanced homogeneously, and in most cases it enhanced to a similar degree as or more than tumor. Marrow and, more specifically, soft tissue edema is a frequent finding adjacent to primary bone tumors. The mere presence and quantity of marrow and soft tissue edema are unreliable indicators of the biologic potential of a lesion. Unenhanced MR scans cannot always differentiate between tumor and edema, but the administration of Gd-DTPA is of assistance in differentiating tumor from edema.(ABSTRACT TRUNCATED AT 250 WORDS)     

Bladder tumors: staging with gadolinium-enhanced oblique MR imaging

To clarify the importance of imaging plane in evaluation of invasion by tumor into muscle, 50 patients with bladder tumors underwent examination with magnetic resonance (MR) imaging performed with an oblique plane and the early phase of contrast enhancement. After the ideal oblique plane was selected, an oblique T2-weighted image was obtained. Gadopentetate dimeglumine was then administered, and an oblique T1-weighted image was obtained. The staging based on oblique T2-weighted and oblique contrast material-enhanced T1-weighted MR images was then correlated with histopathologic staging. The respective accuracies of oblique contrast-enhanced T1-weighted and oblique T2-weighted images were 78% and 60% for overall staging (P < .05), 90% and 74% for differentiation between (a) stage T1 and lower-stage tumors and (b) stage T2 and higher-stage tumors (P < .05), and 92% and 88% for differentiation between (a) stage T2 and lower-stage tumors and (b) stage T3a and higher-stage tumors (P > .05). Oblique MR imaging performed in conjunction with the early phase of contrast enhancement showed significantly high staging accuracy, especially in differentiation between superficial tumors and tumors with superficial muscle invasion.     

Multivoxel proton MR spectroscopy and hemodynamic MR imaging of childhood brain tumors: preliminary observations

PURPOSE: To assess multivoxel proton MR spectroscopy combined with MR imaging and hemodynamic MR imaging in the evaluation of brain tumors in children and young adults. METHODS: Fifteen patients with brain tumors and 10 healthy children underwent MR imaging and MR spectroscopy on a 1.5-T system. Ten patients with tumors had both MR spectroscopy and hemodynamic MR imaging. MR spectroscopy data sets with 1 cm3 to 3.4 cm3 resolution were acquired within 8.5 minutes by using a point-resolved spectroscopic, chemical-shift imaging technique in two dimensions with volume preselection. MR imaging was performed using fast spin-echo techniques. Hemodynamic MR imaging data were acquired every 2.5 seconds at one anatomic level using a spoiled gradient-echo sequence during intravenous bolus administration of contrast material. RESULTS: Assessment with multivoxel MR spectroscopy and hemodynamic MR imaging added about 30 minutes to the total MR examination time. Normal tissue exhibited spectral peaks from biologically significant compounds such as N-acetylaspartate (NAA), choline-containing compounds (Cho), and total creatine (tCr). Twelve biopsy-proved tumors exhibited prominent Cho, reduced NAA, variable tCr, and/or lactate or lipids, and two showed increased hemodynamic parameters. Three of the tumors treated with radiation did not reveal prominent levels of Cho. Tissue necrosis had no Cho, NAA, or tCr, and reduced hemodynamics. CONCLUSIONS: Preliminary findings by MR spectroscopy combined with MR imaging and hemodynamic MR imaging suggest that regions of active tumor may be differentiated from areas of normal tissue and areas of necrosis. These findings may enable metabolic and hemodynamic characterization of childhood brain tumors as well as suggest their response to therapy.     

Diagnosis of intraductal spread of breast cancer by high-resolution MR imaging: correlation between MR imaging and pathohistological findings

The main purpose of this study was to investigate pathohistological factors that affect the MR findings of intraductal spread (IDS) of breast cancer. The subjects of the present study were 42 breast cancer patients who were examined by MR imaging. Fat-suppressed high-resolution T1-weighted spin-echo images [350/13/1 (TR/TE/excitations), 16-cm FOV, 5-mm section thickness, and 512 x 256 matrix] were obtained one minute after the intravenous administration of Gd-DTPA. In this protocol, contrast determination time was 1 min 48 sec. Of the 42 cases, IDS was found to be located more than 1 cm from the primary focus in 22 cases (52%). Rates of sensitivity, specificity and accuracy of MR imaging for the detection of IDS were 82%, 80%, and 81%, respectively. The probable cause of misdiagnosis was parenchymal enhancement due to severe fibrocystic disease and normal menstrual cycle. In 21 of 42 cases, the MR findings were precisely correlated with the pathohistologic findings of almost the same cross-section. The MR findings of IDS varied greatly with observation of linear, band-like, branch-like, plate-like and minute ring enhancements. These findings closely reflected the size, aggregation pattern, and distribution of intraductal lesions. In particular, minute ring enhancement was only observed in 4 comedo-type lesions. This pattern of enhancement is considered to reflect elevated intraductal cellular density with necrosis in the central region.     

Detection of hepatic tumors: arterial-phase MR imaging versus spiral CT arteriography

BACKGROUND: Distinction between uncomplicated infective fasciitis and early necrotizing fasciitis can be extremely difficult without operation, yet the management and prognosis of both conditions depend greatly on early recognition and assessment of the extent of involvement. STUDY DESIGN: This was a prospective review of the utility of magnetic resonance imaging (MRI) in nine patients with suspected infective or necrotizing fasciitis treated at an academic medical center or a Veterans Administration hospital. RESULTS: Magnetic resonance imaging documented fascial inflammation, characterized by low intensity on T1-weighted images and high intensity on T2-weighted images, in all nine patients. Absence of gadolinium contrast enhancement on T1-weighted images reliably detected fascial necrosis in all six patients who required operative debridement. Magnetic resonance imaging was extremely useful in defining the extent of fasciitis and was more accurate in predicting necrosis or pyomyositis than was myoglobinuria or elevation of serum creatine kinase or lactate dehydrogenase. Operation was avoided in two patients without evidence of necrosis on MRI. One patient without evidence of necrosis, explored because of contradictory clinical findings, was confirmed at operation to have cellulitis without necrosis. CONCLUSIONS: Magnetic resonance imaging with gadolinium contrast accurately determines the presence of necrosis and the need for operation in patients with fasciitis of the lower extremity. Preoperative determination of the extent of involvement facilitates operative planning.     

Dynamic MR imaging of liver tumors: analysis with temporal reconstruction images

PURPOSE: To graphically display the time dependency of contrast enhancement of liver tumors at examination with dynamic magnetic resonance (MR) imaging. MATERIALS AND METHODS: A temporal reconstruction image was generated by obtaining a line of interest drawn on a single image through the liver and the tumor and reformatted over a sequence of temporal images. This calculated image expressed the temporal evolution of the line, including nontumoral liver and tumor, with regard to three variables: signal intensity, enhancement, and velocity. This allowed a visually integrated analysis of 95 hepatic lesions studied with dynamic single-section MR imaging after contrast material administration. RESULTS: Temporal reconstruction images were obtained for all the dynamic studies. Five patterns of enhancement based on signal intensity and velocity variations coupled with morphologic information were found: wall, diffusion, moderate enhancement, marked progressive, and early intense patterns. CONCLUSION: Temporal reconstruction of liver tumors after contrast material administration can be used to analyze, describe, and report the dynamics of lesion enhancement with morphologic and temporal resolution.     

MR imaging

MRI is a tool of unprecedented capabilities for evaluating arthritis and its progression. Not only can it non-invasively delineate the anatomy of all components of a joint with unparalleled clarity, MRI is also capable of probing important functional and compositional parameters of disease in these tissues. Particularly intriguing is MRI's potential for identifying very early changes of joint disease when clinical symptoms may be minimal or absent. Early detection of patients who are at risk for developing progressive disease may allow appropriate treatment to be initiated earlier, when there may be a greater chance of favourable outcome. MRI can, furthermore, provide objective and quantitative measures of disease progression and treatment response. Certain parameters, such as articular cartilage volume, have been validated cross-sectionally; however, their longitudinal performance has yet to be established. Further work is, therefore, necessary to thoroughly validate and optimize some of these measures so that they can begin to be used in more powerful ways to explore the pathophysiology and potential therapies of arthritic disorders.     

Pulsed magnetization transfer contrast for MR imaging with application to breast

The relative populations and transverse relaxation times of the solid-like hydrogen pool (PB and T2B) and the magnetization transfer (MT) rates between the solid-like and liquid-like hydrogen pools (kappa) have been determined for three different agar gel concentrations (2%, 4%, and 8% by weight) as well as excised fibroglandular breast tissue specimens. PB was determined to be .003(.001), .01(.002), .02(.01), and .06(.01); T2B was determined to be 13.0(.2), 14.0(.1), 14.5(.1) and 15.2(1.3) microseconds; and kappa was determined to be 0.78(.01), 1.15(.02), 2.00(.02), and 3.55(1.5) sec-1 for the 2%, 4%, and 8% agar gels and the fibroglandular tissue, respectively. The image signal intensities of a pulsed MTC-prepared gradient-echo imaging technique are predicted using these MT parameters and are shown to agree well with experimental data obtained from a clinical MR imaging system. This technique is shown to suppress signal intensity of fibroglandular breast tissue by 40%-50% without exceeding SAR limits (< or = 8 W/kg) and is helpful for visualizing lesions and silicone implants.     

2-[C-11]thymidine imaging of malignant brain tumors

Malignant brain tumors pose diagnostic and therapeutic problems. Despite the advent of new brain imaging modalities, including magnetic resonance imaging (MRI) and [F-18]fluorodeoxyglucose (FDG) positron emission tomography (PET), determination of tumor viability and response to treatment is often difficult. Blood-brain barrier disruption can be caused by tumor or nonspecific reactions to treatment, making MRI interpretation ambiguous. The high metabolic background of the normal brain and its regional variability makes it difficult to identify small or less active tumors by FDG imaging of cellular energetics. We have investigated 2-[C-11]thymidine (dThd) and PET to image the rate of brain tumor cellular proliferation. A series of 13 patients underwent closely spaced dThd PET, FDG PET, and MRI procedures, and the image results were compared by standardized visual analysis. The resulting dThd scans were qualitatively different from the other two scans in approximately 50% of the cases, which suggests that dThd provided information distinct from FDG PET and MRI. In two cases, recurrent tumor was more apparent on the dThd study than on FDG; in two other patients, tumor dThd uptake was less than FDG uptake, and these patients had slower tumor progression than the three patients with both high dThd and FDG uptake. To better characterize tumor proliferation, kinetic modeling was applied to dynamic dThd PET uptake data and metabolite-analyzed blood data in a subset of patients. Kinetic analysis was able to remove the confounding influence of [C-11]CO2, the principal labeled metabolite of 2-[C-11]dThd, and to estimate the flux of dThd incorporation into DNA. Sequential, same-day [C-11]CO2 and [C-11]dThd imaging demonstrated the ability of kinetic analysis to model both dThd and CO2 simultaneously. Images of dThd flux obtained using the model along with the mixture analysis method for pixel-by-pixel parametric imaging significantly enhanced the contrast of tumor compared with normal brain. Comparison of model estimates of dThd transport versus dThd flux was able to discern increased dThd uptake simply on the basis of blood-brain barrier disruption retention on the basis of increased cellular proliferation. This preliminary study demonstrates the potential for imaging brain tumor cellular proliferation to provide unique information for guiding patient treatment.     

Collision tumors of the adrenal gland: demonstration and characterization at MR imaging

PURPOSE: To evaluate the magnetic resonance (MR) imaging findings in collision tumors of the adrenal gland. MATERIALS AND METHODS: MR images obtained in 104 patients with a known primary malignant tumor and an adrenal mass were reviewed to find adrenal glands that contained two contiguous but histologically distinct masses. The findings in such cases were correlated with histopathologic findings. RESULTS: In two (2%) cases, both MR and histopathologic findings showed a mass within the adrenal gland that consisted of contiguous adrenal adenoma and metastasis, which represented a collision tumor. The adenomatous component in each tumor showed a (quantitative) decrease in signal intensity relative to that of the liver (79% and 61%) on opposed-phase images, whereas the metastatic component showed an increase in signal intensity (50% and 15%). Similarly, the adrenal lesion-to-spleen signal intensity ratio on opposed-phase images was lower for the adenomatous component in each (0.39 and 0.43) than for the metastatic component (1.17 and 0.90). CONCLUSION: MR imaging can demonstrate and enable characterization of the separate components of collision tumors within the adrenal gland. These findings can be crucial in planning and guiding subsequent percutaneous needle biopsy and patient care.     

Diagnosing breast implant rupture with MR imaging, US, and mammography

A total of 135 symptomatic women with 262 breast implants were examined with magnetic resonance (MR) imaging performed with a body coil, ultrasound (US), or both to determine imaging features of implant rupture. Surgical proof was available for 33 women with 62 implants; 24 were ruptured and 38 were intact. Complicated internal structure was the most reliable predictor of implant rupture: Diffuse low-level echoes were seen on sonograms in 56% of ruptured implants; internal membranes (which correspond to the collapsed implant shell) were seen on MR images in 58% of ruptured implants. Fluid droplets were seen within the silicone in 26% of ruptured implants on MR images. Irregular implant contour can be a sign of rupture but is unreliable. Fluid collections around silicone implants are not a sign of rupture. At present, neither US nor conventional MR imaging with a body coil is sufficiently reliable to advocate routine screening of asymptomatic women with breast implants. Evaluation with MR imaging performed with a surface coil is more reliable.     

Compression device to reduce motion artifacts at contrast-enhanced MR imaging in the breast

We reported previously that thymic lymphomas from mice expressing transgenic TCR autoreactive against male (HY) antigen were resistant to anti-CD3 antibody-mediated induction of apoptosis although they were responding to TCR triggering. To test whether thymic lymphomas were specifically resistant to TCR-dependent Ca(++)-mediated induction of apoptosis, we have measured apoptosis of cells treated with Ca(++)-dependent (ionomycin, A23187) and Ca(++)-independent (etoposide, dexamethasone) inducers of apoptosis. Here we show that, unlike thymocytes, all thymic lymphomas were resistant to Ca(++)-dependent but not to Ca(++)-independent induction of apoptosis. These results excluded a general defect of apoptosis in lymphoma cells and suggested a specific inhibition of the calcium-mediated (TCR-dependent) pathway of apoptosis in lymphomas. Interestingly however, nuclear expression of a specific mediator of TCR-dependent apoptosis Nur77 was induced in ionomycin-resistant lymphomas indicating that, unlike normal thymocytes, thymic lymphomas are resistant to Nur77-mediated apoptosis.     

Cytology of malignant endometrial tumors

Endometrial cytology is made by direct endometrial sampling. It allows the appreciation of the hormonal status and the diagnosis of inflammatory and/or tumoral pathology. Evidence has been presented that the rate of endometrial cancer is on the increase. Thus, detection and diagnosis have acquired a new significance, where endometrial cytology takes a particular place. Cytologic features of adenocarcinomas in their different kinds are presented. Furthermore, cytologic aspects of uterine sarcomas are outlined, including leiomyosarcomas whose diagnosis can be made by the mean of endometrial cytology.     

Prevention of malignant skin tumors

Sunlight is undoubtedly one of the main reasons of premature aging of the skin. UVB rays as well as UVA rays cause skin damage; therefore, suntan products should contain both UVB and UVA filters and pigments providing high sunray protection. Modern suntan preparations offer the appropriate base for every skin type. Loss of hydration has to be offset. As a consequence, cosmetical suntan lotions not only protect against sunrays, but also must moisturize the skin and care for it.     

MR imaging of intramuscular hemangiomas

Magnetic resonance images of eight surgically confirmed intramuscular hemangiomas were correlated with the pathologic findings. T1- and T2-weighted images were obtained in all cases; STIR images were also obtained in six cases, and fat-suppressed enhanced images in seven cases. All eight hemangiomas showed markedly high signal intensity on T2-weighted images. Linear and round low-signal-intensity components within hemangiomas corresponded to fibrous tissues, high flow vessels and phleboliths. Fat-suppressed enhanced images were superior to images without fat suppression in defining the extent of lesions. STIR images were useful in defining the extent of hemangiomas with infiltration into surrounding tissues. MRI is useful for distinguishing intramuscular hemangiomas from other soft tissue tumors and also supplies valuable information about the extent of the lesions.