Transverse bayonet dislocation of the distal interphalangeal joint--a case report

Transverse bayonet dislocation of an interphalangeal joint is an unstable injury caused by the disruption of both collateral ligaments. This injury pattern in proximal interphalangeal joint was first described by Patel et al. (Clin Orthop Rel Res. 1978;133:219), who coined the term "bayonet dislocation" to describe this particular type of injury. The case of a distal interphalangeal transverse dislocation is presented. This dislocation was successfully treated by closed reduction and immobilization with an aluminum splint and buddy taping to the adjacent finger.

Percutaneous fibrin glue therapy of meningeal cysts of the sacral spine

OBJECTIVE

We assessed CT-guided percutaneous injection of fibrin glue to manage meningeal cysts of the sacral spine in patients with back pain.

CONCLUSION

All patients experienced resolution or marked improvement of symptoms for as long as 23 months after fibrin glue therapy. No patients experienced recurrence of symptoms during the follow-up interval. Percutaneous CT-guided fibrin glue therapy for sacral meningeal cysts may be a more definitive therapy than repetitive cyst aspiration.

Percutaneous release of trigger digit with and without cortisone injection

Percutaneous release was done using the tip of an 18-gauge, 2.5-cm-long needle, mounted on a 3-mL3 syringe in 225 trigger digits. It was successful in 92 (89%) of the digits without cortisone injection (n = 105) and in 115 (96%) of the digits with cortisone injection (n = 120). Negligible or intermittent pain persisted for 8 weeks in the noncortisone group and 6 weeks in the cortisone group after percutaneous release. Of the first 10 digits, 2 needed repeat percutaneous release. With modification of technique, the incidence of repeat percutaneous release was zero in both groups. Open release was needed in 8% in the noncortisone group and 3% in the cortisone group. The procedure was done under local infiltration anesthesia in the office. This reduced patient anxiety, inconvenience and hospital cost.

Detection of hyperacute primary intraparenchymal hemorrhage by magnetic resonance imaging

BACKGROUND

MRI has become increasingly used in the acute setting to manage patients with stroke. There has been concern that MRI may not be sensitive in the detection of acute intracranial hemorrhage. We assessed whether strongly susceptibility-weighted MRI would be sensitive to intraparenchymal hemorrhage in the first few hours.

CASE DESCRIPTIONS

In the course of our ongoing studies of MRI of acute ischemic stroke in more than 200 patients, 35 patients had MR studies within 6 hours. Six of these patients who presented with acute focal symptoms with definite time of clinical onset (2.5 to 5 hours) were found to have evidence of intraparenchymal hemorrhage. Standard T1- and T2-weighted MR scans were performed. In 5 of the patients, echo-planar imaging and gradient-echo sequences were performed to increase the sensitivity of magnetic susceptibility effects of the pulse sequences. Four of the cases were of putaminal hemorrhage and 2 were lobar hemorrhages. The hemorrhage was most evident as foci of T2* hypointensity (signal loss) and unambiguous on the more susceptibility-weighted sequences, particularly echo-planar gradient-echo images.

CONCLUSIONS

MRI can detect hemorrhage within 2.5 to 5 hours of onset of clinical symptoms as regions of marked signal loss due to susceptibility effects, whereas conventional MR scans of ischemic stroke may appear normal. These results demonstrate that MR susceptibility sequences may be sensitive to hyperacute hemorrhage and suggest that MR may be an adequate screen for primary intraparenchymal hemorrhage.

MR angiography of the head and neck

A review of the basic physics and techniques for acquiring and evaluating magnetic resonance angiograms is provided, including time-of-flight and phase contrast techniques. Magnetic resonance (MR) angiography is becoming a routine method of evaluating carotid bifurcation atherosclerotic disease in both a screening and diagnostic capacity. The expanding clinical utility of MR angiography in the detection of intracranial aneurysms, characterization of arteriovenous malformations, and evaluation of intracranial atherosclerotic disease are also reviewed. Furthermore, MR angiography allows for the noninvasive diagnosis of arterial dissection. Magnetic resonance venography also allows the confirmation of the previously elusive and likely underdiagnosed entity of cerebral venous thrombosis.

Multiple schwannomas of the ulnar nerve: a case report

Multiple schwannomas may occur as visible tumors or may occur as tumors in situ. The tumors in situ may be missed when the visible tumors are excised. In time, the schwannomas in situ grow and appear to be recurrent, while in fact, they are multicentric. The prognosis on multicentric schwannomas thus remains guarded.

EEG-triggered echo-planar functional MRI in epilepsy

We investigated whether: (1) EEG recordings could be successfully performed in an MRI imager, (2) subclinical epileptic discharges could be used to trigger ultrafast functional MRI images, (3) artifact-free functional MRI images could be obtained while the patient was having the EEG monitored, and (4) the functional MRI images so obtained would show focal signal increases in relation to epileptic discharges. We report our results in two patients who showed focally higher signal intensity, reflective of increased local blood flow, in ultrafast functional MRI timed to epileptic discharges recorded while the patients were in the imager and compared with images not associated with discharges. One patient showed a focal increase despite a clinical and EEG history of generalized discharges. This approach may have the potential to identify brain regions activated during brief focal epileptic discharges.

M6P/IGF2 receptor: a candidate breast tumor suppressor gene

The mannose 6-phosphate/insulin-like growth factor 2 receptor (M6P/IGF2r) functions in the activation of TGFbeta, a potent growth inhibitor for most cell types, the degradation of the mitogen, IGF2, and the intracellular trafficking of lysosomal enzymes. We have found its expression to be significantly reduced in both rat and human hepatocellular carcinomas (HCCs) and recently reported loss of heterozygosity (LOH) at this locus with mutations in the remaining allele in human liver tumors. Using the polymerase chain reaction, we utilized two polymorphisms in the 3' untranslated region of M6P/IGF2r to screen breast tumors for LOH. Forty of 62 (65%) patients were informative (heterozygous) and 12/40 (30%) breast tumors had LOH; 5/19 (26%) carcinomas in situ (CIS) and 7/21 (33%) invasive carcinomas. To investigate the early molecular genetic events in breast carcinogenesis, we screened the CIS with LOH for mutations. In 2/5 (40%) of these tumors, missense mutations were found in the remaining allele that gave rise to significant amino acid substitutions. These findings provide evidence that M6P/IGF2r allelic loss is an early event in the etiology of breast cancer, that this gene functions as a tumor suppressor gene in the breast.

Intraepineurial constriction of nerve fascicles in pronator syndrome and anterior interosseous nerve syndrome

In PS or AINS, if obvious epineurial compression deformity of the median nerve or the AIN is not found at known sites of compression, IeCNF should be considered. IeCNF may occur in one or more nerve fascicles of the median nerve at one of multiple levels in the distal upper arm and proximal forearm. Decompression of the nerve fascicles is achieved by epineurotomy, microsurgical interfascicular dissection, and removal of the constricting outer layer of the perineurium above and below the elbow. Resection of the constricted segments of the nerve fascicles is not necessary. Intraepineurial exploration of the nerve trunk also may be considered if, after surgical decompression of PS and AINS, expected recovery has not occurred and there is no evidence of axonal degeneration.

Postoperative cerebrospinal fluid leaks of the lumbosacral spine: management with percutaneous fibrin glue

PURPOSE

To assess CT-guided injection of fibrin glue for the management of lumbosacral cerebrospinal fluid (CSF) leaks.

METHODS

Six consecutive patients with postoperative CSF leaks were treated after CSF aspiration under CT guidance. A solution of cryoprecipitate was simultaneously injected with a 10% calcium chloride solution containing 2000 units of thrombin per milliliter. In one patient, 0.5 mL of iopamidol was added to the calcium chloride/thrombin mixture before injection. Placement of the fibrin glue aggregate was confirmed by CT imaging. To determine outcomes we reviewed the patients' records, postprocedure imaging studies, and physical findings, and we interviewed the patients directly.

RESULTS

In three patients with postoperative CSF leaks, symptoms resolved after treatment. Despite imaging evidence of successful plug deployment, two other patients still had severe symptoms, and they underwent surgery after 2 and 18 hours, respectively. One patient had a continued CSF leak and a headache after 12 hours; follow-up surgery repaired an unsuspected dural tear just distal to the site of original surgery underneath the lamina and not covered by the fibrin glue. After one of the successful procedures, the patient had a fever and a headache, probably because of aseptic meningitis, which resolved after 2 days.

CONCLUSION

Percutaneous CT-guided placement of fibrin glue may provide nonsurgical treatment for postoperative CSF leaks, potentially avoiding a major and technically difficult surgical procedure.

Unusual manifestations of head trauma

Head injury is the leading cause of death in young adults. More than 2 million head injuries occur each year in the United States. Accurate and rapid diagnosis is imperative for the successful management of the trauma patient. The radiologic findings of common manifestations of head trauma have been well described; however, the patient who presents in the post-traumatic period with atypical radiographic findings is at risk for misdiagnosis and delay in treatment. In this essay, we illustrate some unusual findings in head injury that may complicate diagnosis.

Preoperative assessment of the carotid bifurcation. Can magnetic resonance angiography and duplex ultrasonography replace contrast arteriography?

BACKGROUND AND PURPOSE

Noninvasive studies are used with increasing frequency to assess the carotid bifurcation before endarterectomy. Therefore, assessment of their diagnostic accuracies is essential for appropriate patient management. We prospectively evaluate two noninvasive tests, magnetic resonance angiography (MRA) and duplex ultrasonography (DU), as potential replacements for contrast arteriography (CA).

METHODS

A blinded comparison of three-dimensional time-of-flight (TOF) MRA, two-dimensional TOF MRA, and DU in 176 arteries was performed. CA was used as the standard of comparison.

RESULTS

Three-dimensional TOF MRA had a sensitivity of 94%, a specificity of 85%, and an accuracy of 88% for the identification of 70% to 99% stenosis; two-dimensional TOF MRA had a sensitivity and specificity that were approximately 10% lower than those of three-dimensional TOF MRA. DU resulted in a sensitivity of 94%, a specificity of 83%, and an accuracy of 86%. Combining data from three-dimensional TOF MRA and DU, allowing for CA only for disparate results, yielded a sensitivity of 100%, a specificity of 91%, and an accuracy of 94% among concordant noninvasive tests, with CA required in 16% of arteries. MRA accurately differentiated 17 carotid occlusions from 16 high-grade (90% to 99%) stenoses, whereas with DU two patent arteries were identified as occluded and one occluded artery was identified as patent.

CONCLUSIONS

Three-dimensional TOF MRA is the most accurate noninvasive test. Combined use of MRA and DU results in a marked increase in accuracy to a level that obviates the need for CA in a majority of patients.

MR imaging of diseases of the brain: comparison of GRASE and conventional spin-echo T2-weighted pulse sequences

OBJECTIVE

The purpose of this study was to compare a combined gradient and spin-echo (GRASE) technique, which is a rapid T2-weighted imaging sequence, with conventional spin-echo (SE) sequences for imaging brain lesions. The GRASE sequences would allow increased patient throughput with potential cost savings and be useful in uncooperative patients without requiring echoplanar imaging techniques and specialized hardware.

SUBJECTS AND METHODS

Conventional SE and GRASE T2-weighted images of 49 consecutive patients (20-86 years old) were reviewed independently by three neurora-diologists for the presence and characterization of lesions (most of which were nonspecific foci of hyperintensity within the white matter), gray-white matter differentiation, conspicuity of lesions, and periventricular signal abnormality. The MR studies were performed on a 1.0-T Siemens Magnetom Impact scanner, with the SE images obtained using a TR/TE of 2400/40 and the GRASE images obtained using a TR/effective TE of 4400/110.

RESULTS

The number of lesions detected that were 5 mm or larger in maximal diameter did not significantly differ among techniques. For lesions smaller than 5 mm, conventional SE T2-weighted images showed more lesions (p < .01). The SE images were better than the GRASE images for assessing gray-white matter differentiation, conspicuity of lesions, and periventricular signal abnormality. The two hypointense lesions were better assessed on the conventional SE images.

CONCLUSION

Although GRASE imaging may be potentially useful for rapid imaging of the brain, our experience shows it has a markedly diminished sensitivity for detecting lesions smaller than 5 mm in diameter. Currently, GRASE imaging should not replace the routine clinical use of conventional SE sequences.

Perioperative imaging strategies for carotid endarterectomy. An analysis of morbidity and cost-effectiveness in symptomatic patients

OBJECTIVE

To assess the cost-effectiveness of four diagnostic strategies for the preoperative evaluation of symptomatic patients who are potential candidates for carotid endarterectomy (ie, 70% to 99% stenosis): (1) duplex sonography (DS), (2) magnetic resonance angiography (MRA), (3) contrast angiography (CA), and (4) the combination of DS and MRA supplemented by CA for disparate results.

METHODS

Cost-effectiveness analysis based largely on published clinical trial data. Sensitivities and specificities of noninvasive tests were estimated from 81 patients undergoing prospective evaluation with DS, MRA, and CA.

OUTCOME MEASURE

Incremental cost per quality-adjusted year of life gained.

RESULTS

For a hypothetical cohort of symptomatic patients undergoing evaluation for carotid endarterectomy, the combination of tests resulted in the greatest quality-adjusted life expectancy of the four options considered. After incorporating the costs of testing, surgery, and stroke, we found that neither the MRA nor the CA strategy was cost-effective. The combination of tests was more effective but more costly than DS, resulting in an additional cost of $22,400 per quality-adjusted year of life gained. For centers that do not have adequate MRA, CA resulted in an additional cost of $99,200 per quality-adjusted year of life saved compared with DS.

CONCLUSIONS

Our results suggest that for the preoperative detection of a 70% to 99% carotid stenosis, the combination of DS and MRA, supplemented by CA for disparate results, is associated with the lowest long-term morbidity and mortality and has a favorable cost-effectiveness ratio. The combination of tests, or DS alone when MRA is not available, could potentially replace the current practice of using CA alone in the preoperative evaluation of patients with symptomatic carotid stenosis.

Brain lesions in patients with multiple sclerosis: detection with echo-planar imaging

PURPOSE

To evaluate the detection of brain lesions with echo-planar imaging relative to conventional spin-echo (SE) imaging.

MATERIALS AND METHODS

In 17 patients (three men, 14 women; mean age, 31 years) with multiple sclerosis, the following were compared: single-shot proton-density- and T2-weighted and thin-section T2-weighted echo-planar, proton-density- and T2-weighted multishot echo-planar, and conventional SE sequences. Quantitative and qualitative criteria as well as lesion detectability were evaluated. The proton-density-weighted SE sequence was used as the standard of reference.

RESULTS

Multishot sequences were superior to single-shot sequences in image quality and lesion detectability. With the multishot proton-density-weighted sequence, 53 of 54 large lesions and 23 of 30 small lesions were detected; with the single-shot proton-density-weighted sequence, 38 of 54 large lesions and five of 30 small lesions were detected.

CONCLUSION

With multishot echo-planar sequences, detectability of large lesions is similar to that with conventional SE imaging. Susceptibility artifact is diminished in comparison to single-shot echo-planar sequences.

Diffusion and perfusion imaging techniques

Diffusion imaging techniques including the Stejskal-Tanner and the stimulated emission of amplitude echoes (STEAM) pulse sequences are discussed. The calculation of apparent diffusion coefficient (ADC) maps is reviewed. The perfusion imaging techniques of blood oxygen level dependent (BOLD) and first pass bolus perfusion techniques as well as the newer technique of echo-planar imaging with signal targeting and altering radiofrequency (EPISTAR) are also discussed. Finally, the theory of intravoxel incoherent motion (IVIM) and its relationship to both diffusion and perfusion phenomena is examined.

Stroke and ischemia

With the introduction of diffusion imaging the diagnosis and acute stroke can be made within minutes of clinical onset. In combination with perfusion imaging, tissue viability can be assessed. The etiology of ischemia can in most cases be investigated by MR angiography. The current applications of these techniques are reviewed, and pitfalls as well as problems in the diagnosis of acute stroke are discussed. With the availability of these techniques, patients can almost instantaneously be approved for pharmacotherapy and monitored and thus clinical outcome potentially can be improved tremendously.

Dissection of the carotid and vertebral arteries: imaging with MR angiography

Arterial dissection occurs when an intimal tear allows blood to enter the arterial wall, potentially compromising the lumen and reducing blood flow. Carotid and vertebral artery dissections typically occur after major trauma, although they also can arise spontaneously or after trivial injury. Arterial dissection has been associated with a variety of factors, including hypertension, fibromuscular dysplasia, Marfan syndrome, cystic medial necrosis, oral contraceptives, drug abuse (sympathomimetics), and infection [1-8]. It is important to recognize arterial dissection early so that prompt treatment can be initiated to prevent ischemic complications [1]. In this essay, we illustrate the use of MR angiography in the diagnosis of carotid and vertebral artery dissection.

MR angiography of the carotid bifurcation: artifacts and limitations

Although conventional angiography has traditionally been the preoperative study of choice before carotid endarterectomy, alternative noninvasive methods, particularly MR angiography, are being used increasingly for evaluation of the carotid bifurcation [1, 2]. In this essay, we illustrate the limitations of and artifacts associated with two-dimensional (2D) and three-dimensional (3D) time-of-flight (TOF) MR angiography vs conventional angiography when assessing disease of the carotid bifurcation.