T1 rho dispersion imaging of head and neck tumors: a comparison to spin lock and magnetization transfer techniques

The potential of T1 rho dispersion, spin lock (SL), and magnetization transfer (MT) techniques to differentiate benign and malignant head and neck tumors was evaluated. Twenty-four patients with pathologically verified head and neck tumors were studied with a .1-T MR imager. T1 rho dispersion effect was defined as 1 -(intensity with lower locking field amplitude/intensity with higher locking field amplitude). T1 rho dispersion effects were higher for malignant than benign tumors (P = .001). With T1 rho dispersion effect .14 as the threshold, sensitivity for detecting a malignant tumor was 91%, specificity was 77%, and accuracy was 83%. A strong correlation between T1 rho dispersion effects and SL effects and between T1 rho dispersion effects and MT effects in the head and neck tumors was found (r = .87, P < .001 and r = .90, P < .001, respectively). High T1 rho dispersion effects are not specific indicators of malignancy, because chronic infections, some benign tumors, and malignancies may overlap. Low T1 rho dispersion effect values are characteristic of a benign tumor.

Aspartylglucosaminuria: radiologic course of the disease with histopathologic correlation

Twelve living patients (aged 19 months to 32 years) with aspartylglucosaminuria were examined by magnetic resonance imaging (MRI), and the magnetic resonance (MR) images of 16 health volunteers (aged 4 to 32 years) were used as controls. One patient was examined twice. Postmortem MRI and histopathologic analysis were done on the brains of four additional adult patients. Signal intensities determined quantitatively on T2-weighted images differed significantly between patients and controls, being higher from the white matter (P < .0002) and lower from the thalami (P < .03) in the patients. The generally increased signal intensity of the white matter was most obvious in the young patients, with many focal areas of very high signal intensity in the subcortical white matter. The subcortical white matter showed a somewhat increased signal intensity even at the age of 32 years. In two of the four postmortem MR images, the distinction between the gray and white matter was still poor. At histopathologic analysis, the basic cortical cytoarchitecture was generally preserved but most neurons contained vacuoles, which were also found in the neurons of the deep gray matter. In two of the four autopsy cases the white matter showed diffuse pallor of myelin staining and some gliosis. Thus aspartylglucosaminuria is primarily a gray-matter disease also affecting white matter by delaying myelination.

Somatosensory evoked magnetic fields from primary sensorimotor cortex in juvenile neuronal ceroid lipofuscinosis

The present study evaluated neurophysiologic function of the primary sensorimotor cortex in juvenile neuronal ceroid lipofuscinosis. A 122-channel magnetometer, which allowed studies of the somatosensory system in millimeter and millisecond precision, was used to record somatosensory evoked magnetic fields to median nerve stimulation from 10 patients and their matched control subjects. In both patients and controls, the somatosensory evoked magnetic fields from primary sensorimotor area typically consisted of N20m, P35m, and P60m deflections. In the patients, N20m was significantly delayed, whereas P35m peaked earlier than in the control subjects. The source strengths for N20m and P35m were greater in the patients than in the controls. Both deflections showed a significant positive correlation with the disease duration: the sources were stronger in the older patients than in the younger ones. P60m deflections were normal or reduced in the patients. The results indicated increased thalamocortical excitability in the sensorimotor cortex in juvenile neuronal ceroid lipofuscinosis.

Variable agreement between visual rating scales for white matter hyperintensities on MRI. Comparison of 13 rating scales in a poststroke cohort

BACKGROUND AND PURPOSE

Previous reports on the frequency, extent, and clinical correlates of white matter hyperintensities (WMHIs) have been contradictory. The purpose of this study was to test whether part of this variation could be explained by the different properties of the visual WMHI rating scales used.

METHODS

The periventricular (PVHIs) and deep white matter (DWMHIs) hyperintensities of 395 poststroke patients were systematically analyzed and transformed to correspond to 13 different rating scales. The scales were compared with the use of Goodman-Kruskal measures of association. The relative frequencies, means, and medians of PVHI and DWMHI grades as well as Spearman rank correlations between WMHI grade and hypertension were calculated.

RESULTS

At best more than 80% of the patients received an equivalent WMHI grade by different scales, but at worst the corresponding values were only 0.4% for PVHI and 18% for DWMHI. At best different scales categorized patients similarly in regard to WMHI grade, but at worst the corresponding values were 8% for PVHI and 57% for DWMHI ratings. The distribution of WMHI grades also varied, and when the effect of age on WMHI was assessed, some of the scales had a ceiling effect and some had a floor effect. Only 1 of the 7 PVHI, 5 of the 9 DWMHI, and 1 of the 3 combined rating scales showed a significant correlation with arterial hypertension, a putative risk factor for WMHIs.

CONCLUSIONS

Some of the inconsistencies in previous studies of WMHIs are due to differences in visual rating scales. Our findings may warrant international debate regarding harmonization of WMHI ratings.

Plasma levels of prekallikrein, alpha-2-macroglobulin and C1-esterase inhibitor in patients with urticarial reaction to contrast media

PURPOSE

The plasma levels of prekallikrein, alpha-2-macroglobulin and C1-esterase inhibitor (C1 INH) in patients with previous urticarial reaction to contrast media (CM) were compared to those of a group of nonreacting age- and sex-matched controls. This study evaluated the value of these laboratory variables in predicting acute and delayed urticarial-type reactions.

MATERIAL AND METHODS

The study comprised 44 patients (reactors) with acute (n = 29) or delayed (n = 15) urticaria after administration of CM, and a group of age- and sex-matched controls.

RESULTS

In the reactors, the levels of prekallikrein and alpha-2-macroglobulin were higher (p < 0.0001) and the level of C1 INH lower (p < 0.0001) than those of the controls. The level of prekallikrein decreased with increasing age (p = 0.02) and women had higher values than men (p = 0.0054). The level of alpha-2-macroglobulin was age-dependent (p = 0.006).

CONCLUSION

Although high plasma prekallikrein activity, high plasma alpha-2-macroglobulin activity, and low plasma C1 INH activity are associated with urticaria-type reaction to CM, their value in predicting urticarial reaction is limited because prekallikrein is age- and sex-dependent, and alpha-2-macroglobulin is age-dependent.

Suppression of alternative complement pathway activity by radiographic contrast media

The authors examined the effect of four different kinds of contrast media (ionic/non-ionic, monomer/dimer) on the activation of the complement (C) system (haemolytic activity and anaphylatoxin generation) in vitro. In addition, the authors compared the effect of contrast media on inulin-mediated generation of the anaphylatoxin derivative C3a des Arg in sera from urticarial reactors and their non-reacting controls. It was observed that the incubation of commercial iohexol, ioxaglate, iodixanol and meglumin amidotriz solutions in normal human serum (NHS) resulted in a dose-dependent decrease in the haemolytic activity of the alternative C pathway. Contrary to expectations the contrast media did not activate C in NHS. Instead, inulin-induced generation of C3a des Arg was inhibited by all the four contrast media. The strongest inhibitor was ioxaglate, an ionic dimer. No significant difference between the urticarial reactors and non-reactors in the inhibition of C3a des Arg generation was observed. In analyzing the mechanism of C inhibition we found that the contrast media solutions, particularly the ionic ones, prevented formation of the alternative pathway C3 convertase, C3bBb, by inhibiting the binding of factor B to surface-associated C3b molecules. The results suggest that the previously observed decrease in haemolytic C titres by contrast media is due to direct suppression of C activity rather than activation-induced consumption.

Magnetic resonance imaging during healing of surgically repaired Achilles tendon ruptures

Twenty consecutive patients with 21 surgically repaired Achilles tendon ruptures were imaged with a 0.1-T magnet at 3 and 6 weeks, and at 3 and 6 months after surgery. Clinical follow-up examinations and functional tests were performed at the time of scanning. An intratendinous area of high-intensity signal was observed in 19 of the 21 surgically repaired Achilles tendons at 3 months after surgery on proton density- and T2-weighted images. The three patients with the largest lesions had clinically poor outcomes at 3 months, whereas those with smaller intratendinous lesions had normal recoveries. Furthermore, patients with an abnormal walk at 3 months (N = 5) had statistically larger intratendinous lesions than patients who could walk normally. In all patients the cross-sectional area of the rejoined Achilles tendon showed the largest increase after cast removal (between 6 weeks and 3 months after surgery). In all cases the largest tendon area was measured at 3 months after surgery. Magnetic resonance imaging provides a precise valuable tool to evaluate the postsurgical internal structure of the surgically repaired Achilles tendon.

Improvement of brain lesion detection at 0.1 T by simultaneous use of Gd-DTPA and magnetization transfer imaging

Imaging parameters were optimized at 0.1 T to improve contrast-to-noise ratios (CNR) when combining magnetization transfer (MT) imaging and the use of paramagnetic contrast medium. This was accomplished by imaging a phantom containing serial concentrations of Gd-DTPA in cross-linked bovine serum albumin. With the use of simulations, the dependence of CNR on imaging parameters was studied. Conventional and MT images were obtained from 10 brain tumor patients with single and triple doses of Gd-DTPA. Simulations demonstrated the importance of TR in postcontrast sequences. The CNR in MT images is less sensitive to TR than in conventional images. A significant CNR improvement caused by MT remains at longer TR when there is no contrast enhancement without MT. The clinical results indicate that a single dose of Gd-DTPA combined with MT cannot replace imaging with a triple dose. However, MT significantly improved the CNR after single and triple Gd-DTPA-doses on T1-weighted and proton-density images.

Low-field MRI pelvimetry

The purpose of this study was to evaluate the usefulness of low-field MRI pelvimetry and to correlate the results with X-ray pelvimetry. A total of 19 women underwent low-field MRI pelvimetry. Mediosagittal and transverse planes were used to measure the diameters of the minor pelvic cavity. Correlations between MRI and X-ray pelvimetry were 0.96 for the sagittal inlet, 0.94 for the sagittal outlet, 0.93 for the transverse diameter (diameter transversa, DT) and 0.94 for the bispinous distance (interspinous distance, IS). The repeatability of the measurements was good. For fetuses with cephalic presentation it was also possible to determine the biparietal diameter (BPD). Low-field MRI pelvimetry was well accepted by the patients. The scanning time was less than 6 min, which is comparable with the time of X-ray examination with two planes. Magnetic resonance imaging provides a reliable method to image pelvic structures and soft tissue without ionizing radiation.

Postoperative MR imaging and ultrasonography of surgically repaired Achilles tendon ruptures

PURPOSE

To evaluate and compare MR and US findings in an unselected group of patients with 1-3-year-old surgically repaired complete ruptures of the Achilles tendon.

MATERIAL AND METHODS

Thirteen patients with complete Achilles tendon rupture underwent clinical, MR and US examinations. The average time interval from rupture to postoperative imaging was 18 months.

RESULTS

The cross-sectional area of a postoperative tendon was 4.2 times that of the unaffected side. The shape of the operated tendon was more rounded than the unaffected side and it had irregular margins both in MR imaging and in US examination. In 4 of 13 cases an intratendinous area of intermediate to high signal intensity on proton density- and T2-weighted images was seen on MR. The size of this area varied from 4 to 18% of the cross-sectional tendon area. Two patients with the largest intratendinous area had poor clinical outcome. On US the tendon had mixed echogenicity in all cases and the tendon bands were thinner and shorter than normal. Comparison of dimension between MR and US revealed that in a.p. dimension the correlation was good (r = 0.87, p = 0.001), but in transversal width there was no significant correlation (r = 0.58, p = 0.06).

CONCLUSION

The increased size and round irregular area of the operated Achilles tendon rupture was well detected by both MR and US, but intratendinous lesions were seen only by MR.

Spin lock and magnetization transfer imaging of head and neck tumors

PURPOSE

To evaluate and compare the spin lock and magnetization transfer techniques in the differentiation of benign and malignant head and neck tumors at magnetic resonance (MR) imaging.

MATERIALS AND METHODS

Forty consecutive patients with histologically verified head and neck tumors (20 malignant and 20 benign tumors, including five infections) were studied with a 0.1-T MR unit. The spin lock and magnetization transfer effects were defined as 1-(signal intensity with stronger preparation pulse/signal intensity with weaker preparation pulse).

RESULTS

A strong correlation between the spin lock and magnetization transfer effects was found (r = 85, P < .001). With a spin lock effect of 0.48 and a magnetization transfer effect of 0.32 as the thresholds, sensitivity for detecting a malignant tumor was 95% and 94%, respectively, and specificity was 60% and 65%.

CONCLUSION

Low spin lock and magnetization transfer effects are characteristic of benign tumors. High spin lock and magnetization transfer effects were associated with malignancy, but there were overlapping values for salivary gland infections, some benign tumors, and malignancies. The spin lock technique seems to be an effective method for generating magnetization transfer-based contrast in the head and neck tumors.

Activation of ipsilateral primary sensorimotor cortex by median nerve stimulation

We report evidence for activation of ipsilateral primary sensorimotor cortex (SMI) after median nerve stimulation recorded with magnetoencephalography (MEG). We measured somatosensory evoked magnetic fields (SEFs) to median nerve stimulation with a 122-channel helmet-shaped magnetometer in 10 healthy subjects. In five, the magnetic field patterns suggested long-latency activation of the ipsilateral SMI. Source locations found by current dipole fitting corresponded to the SMI hand area, as determined by contralateral stimulation. Further evidence for the origin of the ipsilateral responses in SMI was provided by the suppression of these responses during movement of the contralateral fingers. Sensory input to ipsilateral SMI could play a role in sensorimotor integration of bilateral movements.

Efficient memory management strategy in hypermedia with interactive MR images

When composing hypermedia with interactive image sets the main problem is to allocate minimal memory of random access memory (RAM). The stand-alone product should be accessible to the public and not require too much memory to maintain interaction between the images and the text. We designed a new hypermedia application using SuperCard and image stacks in PICS format running on a Macintosh LC computer. Memory use was effective since the images were kept in external files outside the application. On browsing cards the images were requested from the image file and each image was displayed within about 1 second as a floating frame on top of the card in the top window. Interactivity when presenting, for example, anatomical parts was achieved by bitmap objects which were activated through the image by pointing at them through the image. By pointing at a text object the corresponding anatomical bitmap object was visualised through the image. The stand-alone version of the application with up to 100 cards runs on a 2 Mb RAM set-up. The maximum sizes of the external image stacks are not dependent on the RAM size.

Echo-planar MR cerebral blood volume mapping of gliomas. Clinical utility

Neovascularization is a common phenomenon in gliomas. MR imaging cerebral blood volume (CBV) mapping utilizes ultrasfast echo-planar imaging and simultaneous use of gadolinium-based contrast material. To determine the utility of MR CBV mapping in the clinical evaluation of gliomas, we followed 15 patients with serial studies. This technique provided functional information that was not evident with conventional CT or MR imaging. Low-grade tumors demonstrated homogeneously low CBV, while high-grade tumors often showed areas of both high and low CBV. The maximum tumor CBV/white matter ratio was compared between low- (n = 3) and high-grade gliomas (n = 5) in patients without previous treatment and with histologic verification (n = 8) and was significantly higher in high-grade gliomas (p < 0.01). High CBV foci in nonenhancing tumor areas were present in 2 cases. The distinction between radiation necrosis and active tumor could be made correctly in 3 of 4 cases. The information provided by MR CBV mapping has the potential to be an adjunct in the clinical care of glioma patients.

Functional cerebral imaging in the evaluation and radiotherapeutic treatment planning of patients with malignant glioma

PURPOSE

Functional magnetic resonance imaging (MRI) and positron emission tomography are relatively new modalities of great potential value in the evaluation, treatment, and subsequent follow-up care of patients with malignant glioma. We report our experience with the incorporation of functional imaging data into radiation therapy three-dimensional (3-D) treatment planning.

METHODS AND MATERIALS

Over a 24-month period, a total of 37 positron emission tomography and 29 functional MRI studies have been conducted on eight consecutive patients prior to, during, and following the completion of radiation therapy. Functional imaging was conducted prior to radiation therapy treatment planning and at approximate 3-month follow-up time intervals.

RESULTS

In two patients, functional imaging provided additional information over conventional imaging modalities and resulted in subsequent modification of conventional radiation therapy treatment planning.

CONCLUSION

Although it is premature to make definitive statements regarding the use of these new imaging parameters in the prognostic setting, functional imaging may likely prove to be a useful adjunct in the initial evaluation, radiation treatment planning, and follow-up care of patients with malignant glioma.

Compression sonography in the diagnosis of deep venous thrombosis of the leg

The value of compression sonography was assessed to reduce the number of phlebographies otherwise necessary when deep venous thrombosis (DVT) is suspected among hospital patients. Compression sonography was used to study 119 prospective hospital patients who were suspected of having DVT of the lower extremity. The results were compared to those by phlebography. There were 44 DVTs detected by phlebography; ten of these were located only in the calf, below the knee. Of the remaining 34 femoropopliteal DVTs 33 were detected by the compression sonography technique. It is concluded that the use of compression sonography for primary investigation of suspected DVT reduces the number of patients who require phlebography to those whose results by compression sonography are negative. In our study, this would have represented a decrease of 28%, corresponding to a reduction of the total diagnostic costs by 10%.

A comparative analysis of similarity mapping and eigenimaging as applied to dynamic MR imaging of a low grade astrocytoma

This paper compares the abilities of similarity mapping and eigenimaging for the purpose of identifying (segmenting) different image structures in dynamic MR imaging. As an illustrative example a case of dynamic images with a low grade astrocytoma was chosen. It was found that the similarity mapping was more successful than eigenimaging in determining the extent and position of a low grade astrocytoma. Also, similarity mapping was able to identify another region with a different and uncorrelated temporal pattern that was later diagnosed as a cyst.

Cerebral blood volume maps of gliomas: comparison with tumor grade and histologic findings

PURPOSE

To assess the utility of magnetic resonance (MR) cerebral blood volume (CBV) maps in the evaluation of gliomas.

MATERIALS AND METHODS

CBV maps from 19 patients with histologically proved gliomas were calculated from dynamic MR image sets acquired with echo-planar spin-echo imaging after intravenous injection of gadolinium-based contrast material.

RESULTS

The maximum CBV varied from 0.82 to 5.40 in the high-grade group (n = 13) and from 1.01 to 1.21 in the low-grade group (n = 6). The difference was statistically significant. Maximum CBV was associated with mitotic activity and vascularity, but not with cellular atypia, endothelial proliferation, necrosis, or cellularity.

CONCLUSION

MR CBV maps provided diagnostic information not available with conventional MR imaging in six cases and offers a functional parameter for assessing glioma grade and regions of focal activity.

Radioimmunoimaging of non-small cell lung cancer with 111In- and 99mTc-labeled monoclonal anti-CEA-antibodies

Radiolabeled monoclonal anti-CEA antibodies were used for radioimmunolocalization (RIL) of non-small cell lung cancer; in 30 patients with 111In labeled anti CEA F(ab')2 fragment (BW 431/31) and in 16 with 99mTc-labeled intact MoAb (BW 431/26). RIL results were compared with those of other imaging modalities. Paraffin sections from some patients were also studied immunohistochemically using anti-CEA antibody. Patients with 111In labeled MoAB were imaged twice 1-4 days after injection and for image enhancement pulmonary and liver/spleen subtraction were performed. Twenty-seven of 28 primary tumors were positive and metastases were detected in all patients. The total number of lesions was 78 of which 61 (78%) could be detected by RIL. For verification CT was applied to the study of 46 lesions detected by RIL. We found 6 unknown lesions subsequently verified histologically. Using subtraction techniques we detected 9 lesions in 4 patients, later verified as pulmonary metastases, not detected in unprocessed images. Pleural, mediastinal and pericardial lesions were also better delineated in subtracted images than in unprocessed images. Imaging of non-small cell lung cancer with 99mTc-labeled MoAB was performed twice 4-24 h after injection. RIL results were compared with other imaging methods; CT US, conventional radiography, and immunohistochemistry. Twelve out of 16 patients with suspected or known lung cancer had positive immunoscintigrams; 19 of 25 lesions could be detected by RIL. There were 5 false positive and 2 true negative findings. Immunoperoxidase (IP) stainings of paraffin sections of the tumours from 7 patients were performed using two different anti-CEA antibodies; BW 431/26 and ZCEA1. None of the seven tumors examined by immunohistochemistry were negative when stained by BW 431/26, which was the antibody used for immunoscintigraphy.

Level of plasma prekallikrein and its inhibitors in reactors and nonreactors during intravenous enhancement with contrast media

Complex contact activation systems may play a major role in the side effects of i.v. contrast media (CM). This is why quantitative measurements of several factors (plasma prekallikrein, hematocrit (hct), alpha-2-macroglobulin, alpha-1-antitrypsin, and C1-esterase inhibitor) were determined prior to and following the injection of CM during body CT examination in 5 patient groups, each (n = 10) receiving one of 5 different CM, including ioxaglate, meglumine iodamide, metrizamide, iohexol, and meglumine diatrizoate. The initial plasma prekallikrein level was available from 45 patients and was statistically lower in reactors (mean 90.6 mumol TAMe/ml/h; n = 13) than in nonreactors (mean 107 mumol TAMe/ml/h; n = 32) (p = 0.006), but there was no statistically significant difference in the decrease of plasma prekallikrein before and at 5 min after the injection for those 2 groups. The initial plasma C1-esterase inhibitor level was lower in reactors, while the plasma alpha-2-macroglobulin level was higher in that group than in nonreactors. The results indicate that the measurement of plasma prekallikrein combined with plasma C1-esterase inhibitor and alpha-2-macroglobulin measurement could be useful when predicting which patients are prone to CM reactions.

Susceptibility contrast imaging of cerebral blood volume: human experience

Magnetic resonance (MR) can offer a unique window on the structure/function relationships in the brain, by utilizing the established link between tissue function, metabolism, and hemodynamics. This report focuses on recent applications of MR-based cerebral blood volume (CBV) imaging in humans. Our methodology uses high-speed "single-shot" or echo planar imaging techniques, which provide the necessary temporal resolution for mapping the rapid cerebral transit of contrast agents. These MR CBV mapping techniques have been used to study normal human brain task activation and in the clinical study of patients with brain tumors. In the latter, positron emission tomography imaging was used for functional metabolic and CBV correlation. Susceptibility contrast CBV imaging should allow us to improve our understanding of the relationship between the detailed physiology and morphology of the microvascular bed and functional attributes of the brain. These techniques can be applied to understanding fundamental questions of cognitive neuroscience and can aid in improving diagnostic sensitivity and specificity in various neuropathologies.

Contrast agents and cerebral hemodynamics

Contrast-enhanced magnetic resonance imaging of regional cerebral hemodynamics is discussed. Techniques for measuring cerebral blood volume (CBV) have been validated in animal models and have recently been applied to human studies. Factors affecting CBV measurement in pathologic tissue are addressed. Extension of these techniques to the measurement of cerebral blood flow is presented.

Imaging of soft-tissue sarcomas with indium-111-labeled monoclonal antimyosin Fab fragments

Some soft-tissue sarcomas contain intracellular myosin. We therefore studied the possibility of localizing various soft-tissue sarcomas with 111In-labeled monoclonal antibody Fab fragments binding specifically to myosin, assuming that damage to the cell membrane could expose intracellular myosin. Nineteen patients with different types of soft-tissue sarcomas were studied. Eighteen patients were found to have abnormal antibody uptakes. Antibody uptake was not observed in an additional patient operated for a benign tumor (gastric leiomyoma). The immunoscintigraphy results were generally in good agreement with those of other radiologic findings (computed tomography, ultrasound, magnetic resonance imaging). Surprisingly, the immunohistochemistry results showed that tumors not stainable for myosin can also be imaged with antimyosin. Thus, the mechanism of antibody uptake does not seem to be related entirely to specific antigen recognition. Irrespective of the exact mechanism for the uptake of labeled antibody this method appears to be useful for localizing soft-tissue sarcomas.

Decrease of plasma prekallikrein and kallikrein inhibitors during intravenous phlebography

Complex contact activation systems may have major involvement in side effects of i.v. contrast media. To investigate this, quantitative measurements of several factors (plasma prekallikrein, kallikrein inhibitory activity, haematocrit, alpha-2-macroglobulin, antithrombin III, alpha-1-antitrypsin and beta-thromboglobulin) were made before and after i.v. contrast phlebography in two groups of patients (each containing 21 patients) with no thrombosis, using a high- (meglumine iodamide) and a low-osmolality (ioxaglate) contrast medium. A statistically significant decrease in plasma prekallikrein was observed after the high-osmolality contrast medium, which is a sign of the activation of the kallikrein-kinin system and an indicator of the activation of the intrinsic coagulation. These events may play an important role in the adverse effects of contrast media.

Sonography in differential diagnosis of deep venous thrombosis of the leg

The lower extremities of 60 consecutive symptomatic patients were examined first by ultrasound (US) and then by phlebography. Deep venous thrombosis was found in 17 patients by means of venography. A hematoma was detected by US in six legs without thrombosis. A popliteal cyst was observed by US in five cases; one patient had a concurrent deep venous thrombosis. It was concluded that symptomatic patients with a negative phlebography should be examined by US for correct diagnosis and treatment, although US cannot replace phlebography.

99mTc-plasmin test in deep vein thrombosis of the leg

A 99mTc-plasmin test and phlebography were performed on 45 consecutive unselected patients with suspected deep vein thrombosis of the leg. Phlebography showed thrombosis in 15 cases. In fourteen of these patients there was a positive result in the plasmin test. Eleven other patients had a positive plasmin test result as well. The most common causes for a false-positive result in the plasmin test in the diagnosis of deep vein thrombosis were acute inflammatory disease and disturbance in venous flow without fresh thrombosis. The sensitivity of the plasmin test in the diagnosis of deep vein thrombosis was 93% and the specificity was 63%. It is concluded that the plasmin test can be used for the screening of deep vein thrombosis.

Thermography in deep venous thrombosis of the leg

Thermography, a fast, simple, and sensitive method, was compared with conventional contrast medium phlebography in the diagnosis of acute deep venous thrombosis of the lower extremities in 141 patients. In 84% of the cases, the results with both techniques agreed. Thermograms showed the pathologic findings in 38 of 41 cases with deep thrombosis. In the three cases with false-negative findings, only the anterior surfaces of the legs were studied. In 19 cases, pathologic thermograms were recorded in the absence of deep thrombosis; the main reasons for findings were posttraumatic, postoperative, and postthrombotic states, and insufficiency of the perforant veins. If a patient has no previous history of a venous or other intervening disease, thermography with a negative finding excludes deep venous thrombosis. If it is used as a primary method, it can replace many phlebographies in the diagnosis of acute deep venous thrombosis.