Breath-hold 3D MR coronary angiography with a new intravascular contrast agent (feruglose)—first clinical experiences

Demonstration of the initial results of breath-hold 3D MR coronary angiography with patients using a new intravascular contrast agent (feruglose). Contrast-enhanced 3D MR-coronary angiography was performed in 5 patients with coronary artery disease after administration of feruglose in three different doses (0.5 (n = 3), 2, 5 mg Fe/kg body weight for each patient). MR coronary angiography was performed with an ECG-triggered 3D-FLASH-sequence during breath-hold at 1.5 T (TR 6.8 ms, TE 2.5 ms, flip-angle 30 degrees ). To reduce data acquisition time, only the two anterior elements of the phased-array body coil were activated. The data acquisition window within the cardiac cycle ranged between 217-326 ms depending on the matrix. Signal-to-noise (SNR) and contrast-to-noise ratios (CNR) of the coronary arteries were analyzed, and the results for the detection of coronary artery stenoses were compared with those obtained by conventional coronary angiography. SNR and CNR revealed an improved image quality at a dose of 2 mg Fe/kg compared with the lower dose, but no further improvement was obtained by rising the dose to 5 mg Fe/kg. Except for the left circumflex artery of one patient, at minimum the proximal parts of all four main coronary arteries could be imaged for all patients. Within the visible parts of the coronary arteries, six of eight significant coronary stenoses were identified correctly. Imaging of the proximal parts of the coronary arteries including detection of stenoses is possible during breath-hold using an intravascular contrast agent.

Deep venous thrombosis and consecutive pulmonary embolism as the first sign of an ovarian cancer: MR angiography using an intravascular contrast agent (CLARISCAN)

We describe a case of progressive deep venous thrombosis and chest pain studied by contrast-enhanced magnetic resonance (MR) angiography with the new intravascular contrast medium CLARISCAN (NC100150 Injection). Combined MR venography and angiography demonstrated pelvic vein thrombosis and consecutive pulmonary embolism caused by a large abdominal tumor, diagnosed as an ovarian cancer after surgery. The potential role of an intravascular contrast medium for studying the vascular system in multiple regions of the body within a single examination without the need for bolus timing is discussed. J. Magn. Reson. Imaging 2000;12:497-500.

Therapeutic immunoadsorption increases the level of circulating soluble HLA molecules

BACKGROUND AND OBJECTIVES

Immunoadsorption (IA) is an established procedure to remove Igs and immune complexes from peripheral blood. Since Igs reportedly bind to human leucocyte antigen (HLA) molecules, we were interested to know whether removal of Ig will also influence the plasma concentration of soluble HLA (sHLA).

PATIENTS AND METHODS

Nine patients suffering from severe autoimmune disease and undergoing 17 single courses of IA treatment were monitored for their sHLA class I (sHLA-I) and sHLA-DR plasma levels. Plasma was separated by a hollow-fiber-type separator. Plasma samples were taken before therapy, after 15 min of recirculation (without operating the adsorber), after 1 and 2 liters of plasma adsorption, and 24 and 48 h after the end of IA.

RESULTS

Before treatment the mean levels of sHLA-I and sHLA-DR were 0.37 (+/-0.06 SEM) and 0. 32+/-0.05 microg/ml, respectively. After 2 liters of plasma filtration, an increase in sHLA-DR (0.80+/-0.10 microg/ml) was observed (p<0.001), whereas sHLA-I was only slightly affected (mean: 0.45+/-0.06 microg/ml). sHLA concentrations returned to initial levels after 24 h.

CONCLUSION

The significant increase in sHLA-DR may contribute to the immunomodulatory effect of IA.

Effect of patient-controlled analgesia on pulmonary complications after coronary artery bypass grafting

OBJECTIVE

To determine whether treatment with patient-controlled analgesia (PCA) alone or in combination with nonsteroidal anti-inflammatory drugs can prevent postoperative pulmonary complications after cardiac surgery, when compared with conventional nurse-controlled analgesia.

DESIGN

Randomized controlled trial.

SETTING

University Medical Center.

PATIENTS

A total of 120 patients undergoing elective coronary artery bypass grafting.

INTERVENTIONS

After extubation of the trachea, 120 patients were randomly allocated to three different methods of postoperative pain relief for 72 hrs. In group 1, patients received PCA with a bolus of 1.5 mg piritramide combined with a 10-min lockout interval. Group 2 patients were treated with a combination of PCA and administration of nonsteroidal anti-inflammatory drugs prescribed three times per day. Patients of group 3 received conventional nurse-controlled analgesia. Postoperative assessment included daily visual analog pain scoring (VAS) and chest radiographs. All chest radiographs were graded for the extent of atelectasis by a radiologist blinded as to treatment using a scale from 0 to 9 for each of the three lung fields of the right and left lungs.

MEASUREMENTS AND MAIN RESULTS

Chest radiograph atelectasis scores and VAS values were similar among the three groups on the first and second days. On the third day, the chest radiograph atelectasis scores of the left lower and the right middle lung field were significantly better in the groups treated with PCA alone (4.7 +/- 3.0; 0.3 +/- 1.0) and in combination with nonsteroidal anti-inflammatory drugs (3.9 +/- 1.1; 0.4 +/- 1.2) than in the control group (5.5 +/- 3.1; 0.8 +/- 1.8). Furthermore, on the third day, the VAS values for maximum pain were higher in the control group (42.6 +/- 19.7) compared with the VAS values in the two groups with PCA (32.2 +/- 17.9 and 34.5 +/- 21.0).

CONCLUSIONS

PCA significantly decreases postoperative pulmonary atelectasis in patients after coronary artery bypass grafting when compared with nurse-controlled analgesia. In addition, patients treated with PCA experienced a higher quality of analgesia. We therefore conclude that treatment with PCA may reduce respiratory complications after coronary artery bypass grafting.

MR imaging of pancreatic lesions. Comparison of manganese-DPDP and gadolinium chelate

RATIONALE AND OBJECTIVES

To compare manganese-DPDP-enhanced and gadolinium-DTPA-enhanced MR imaging in patients suspected of having pancreatic cancer.

METHODS

Fifteen patients who underwent MR imaging for suspected pancreatic cancer and received gadolinium-DTPA took part in a clinical phase III trial in which the efficacy of manganese-DPDP for detection of pancreatic cancer was evaluated. T1-weighted gradient-echo (GRE) images with and without fat suppression were used. Signal-to-noise ratio and contrast-to-noise ratio were calculated before and after the administration of each contrast agent. Image quality was assessed using a four-step score; delineation of the normal pancreas was assessed by two readers in consensus.

RESULTS

In terms of pancreatic signal-to-noise ratio, only gadolinium-DTPA-enhanced fat-suppressed and non-fat-suppressed GRE imaging showed a significant (P < 0.001) increase (72% and 61%, respectively). In the patients with a focal pancreatic lesion (n = 14), a significant increase in contrast-to-noise ratio was found only in manganese-DPDP-enhanced GRE imaging without (106%) and with (82%) fat saturation. Qualitative image analysis demonstrated a significant improvement of manganese-DPDP-enhanced fat-suppressed MR images in delineating the pancreatic parenchyma (P < 0.01) as well as pancreatic tumors (P < 0.01).

CONCLUSIONS

T1-weighted manganese-DPDP-enhanced GRE imaging with fat saturation should be regarded as the most suitable combination for detecting a pancreatic lesion.

Assessment of hepatic perfusion in pigs by pharmacokinetic analysis of dynamic MR images

The purpose of this study was to evaluate a new method based on magnetic resonance imaging for the characterization of hepatic perfusion. In nine pigs dynamic MRI was performed before and after partial occlusion of the portal vein. The pharmacokinetic analysis of the contrast enhancement resulted in a set of parameters (amplitude, A; perfusion rate, kp; elimination rate, kappa(e1); lag time, t(lag)) of which kp was expected to correlate with hepatic perfusion. Reference measurements were done with ultrasound flow-meters and with a thermal diffusion probe (TDP). MR perfusion rate kp significantly dropped under partial portal vein occlusion from an average of 11.3 to 4.9 min(-1) (P < 0.001), while the difference in amplitude A was not significant. The correlation between kp and the TDP measurement was r = 0.89 (P < 0.001). Pharmacokinetic analysis of MRI contrast enhancement provides a non-invasive assessment of hepatic perfusion.

Determination of heparin-induced IgG antibody in heparin-induced thrombocytopenia type II

BACKGROUND

Heparin-induced thrombocytopenia is a relatively uncommon but severe side-effect of heparin therapy. Heparin-induced IgG antibody has been elucidated to be the main isotype and the most pathogenic antibody in the pathophysiology. As affected patients are at high risk of developing thrombotic events, confirmation of the clinical diagnosis and avoidance of heparin re-exposure are important and desirable.

MATERIALS AND METHODS

In the present study, heparin-induced IgG was measured by the binding of neoantigens, which were prepared by incubating FITC-heparin with platelet factor 4 present in normal serum. The cross-reactivities of heparin-induced IgG with low-molecular-weight heparin and danaparoid were analysed by competitive binding.

RESULTS

A total of 81 clinically suspected heparin-induced thrombocytopenia type II patients were analysed. Thirty-seven of 38 heparin-induced thrombocytopenia type II patients, in whom thromboembolism was confirmed by objective methods, had elevated relative fluorescence intensity ratios (patient normal control) and 36 had positive heparin-induced platelet activation results. The prevalence of heparin-induced IgG in heparin-induced thrombocytopenia type II patients was 97.4%. Positive heparin-induced IgG results were: 0/319 healthy volunteers, 0/38 other thrombo-cytopenia and 2/56 heparin/low-molecular-weight heparin-receiving patients without thrombocytopenia, 2/41 hyperbilirubinaemic patients and 2/50 hyperlipidaemic patients. A small amount of cross-reaction assays showed similar results as obtained in heparin-induced platelet activation.

CONCLUSION

Our results suggest that a very high frequency of heparin-induced IgG in heparin-induced thrombocytopenia type II patients can be detected using a novel antigen assay. The rapid determination of pathogenic heparin-induced IgG may be a useful tool for the rapid diagnosis of heparin-induced thrombocytopenia type II that could facilitate further management of the patients.

[Promoting remyelination as a future therapeutic principle in multiple sclerosis?]

Multiple sclerosis (MS), the most common neurological autoimmune disorder diagnosed in young adults, is characterised by the repeated occurrence of demyelinating lesions within the central nervous system (CNS). Promotion of remyelination in the brain and spinal cord constitutes a potential strategy for therapeutic intervention in MS and other demyelinating diseases. Three different principles are known to promote remyelination in the CNS of different animal models: Application of growth factors, transplantation of myelin-forming cells and intravenous immunoglobulin (IVIg) therapy. However, the systemic application of growth factors could be limited by effects on unaffected tissue. For successful transplantation we still have the problem of homologous cells not tolerated by a immunological different organism. Currently the required combination of growth factors needed to cultivate human homologous cells is not known, so that cells suitable for transplantation are still not available. Nevertheless, there is increasing evidence for beneficial effects of IVIg therapy on the promotion of remyelination in humans. In this review we summarise recent findings on the regulation of myelin sheath development and oligodendrocyte differentiation, and discuss the presented strategies in the context of possible clinical application for the therapy of MS.

Pseudolesions at T1-weighted gradient-echo imaging after administration of superparamagnetic iron oxide: comparison with portal perfusion abnormalities at CT during arterial portography

PURPOSE

To compare specific findings at T1-weighted gradient-echo (GRE) magnetic resonance (MR) imaging performed after administration of superparamagnetic iron oxide (SPIO) with nontumorous regional portal perfusion abnormalities seen at computed tomography (CT) during arterial portography (CTAP).

MATERIALS AND METHODS

The results of CTAP, MR imaging, and surgery were compared in 19 patients with liver metastases and five with benign liver tumors. MR imaging was performed by using turbo spin-echo (SE) sequences and a GRE sequence before and after infusion of SPIO.

RESULTS

At CTAP, 34 nontumorous portal perfusion defects ("straight line sign," pseudolesions) were seen. After intravenous administration of SPIO, 18 nontumorous signal intensity differences were seen on T1-weighted GRE images in corresponding locations. No corresponding nontumorous signal intensity differences were seen on unenhanced MR images. The mean signal-to-noise ratio on the SPIO-enhanced GRE images was reduced from 26.3 to 16.6 in the areas of nontumorous signal intensity differences, whereas that in areas of normal portal perfusion (normal CTAP findings) was reduced to 10.2.

CONCLUSION

Impaired portal perfusion decreased the uptake of SPIO in histopathologically normal regions of liver parenchyma. Resultant differences in signal intensity were better visualized on GRE than on turbo SE images.

[Leiomyosarcoma of the inferior vena cava]

HISTORY AND CLINICAL FINDINGS

In a 34-year-old woman who underwent ultrasound investigation because of recurrent pyelonephritis a space-occupying lesion in the liver was an incidental finding. Computed tomography (CT) and magnetic resonance imaging (MRI) confirmed a tumour in segment I of the liver. The patient had been on contraceptives for 12 years. She had no symptoms.

INVESTIGATIONS

Laboratory tests, including tumour markers, were unremarkable. Diagnostic tests to exclude malignant tumour with metastases were negative (thyroid scintigraphy, mammography, coloscopy and gastroscopy). Further tests (ultrasound, coeliaco-mesentericography, hydro-CT and spiral CT, MRI) revealed a tumour, 5 x 4 x 4 cm, in segment I of the liver, most likely an adenoma. Surgical intervention was indicated by the size and questionable malignancy of the tumor.

TREATMENT AND COURSE

At operation a tumour was found which originated from the inferior vena cava (IVC) and displaced segment I of the liver. The tumour was resected and the venous wall reconstructed with a Goretex patch. Histological examination indicated a poorly differentiated leiomyosarcoma of the IVC. Adjuvant radiotherapy was undertaken postoperatively. There has been no evidence of recurrence after 10 months.

CONCLUSIONS

Leiomyosarcoma of the IVC can be mistaken, both by ultrasound and tomographic diagnostic procedures, for a tumour in segment I of the liver, especially an adenoma. A leiomyosarcoma of the IVC should be included in the differential diagnosis of an hepatic tumour that lies close to segment I of the liver.

Epidural abscess after combined spinal-epidural block

PURPOSE

We report the first case of abscess formation after combined spinal-epidural block (CSE). Penetration of the dura in CSE may constitute an additional risk of subarachnoid spread of bacteria when post-puncture epidural infection is present.

CLINICAL FEATURES

The combination of a spinal and a continuous epidural block (CSE) using a needle through needle technique was used in a 72-yr-old man for reconstructive vascular surgery of the lower limb. On the fourth postoperative day the patient demonstrated back pain, fever, and exudation of pus from the CSE-puncture site. An epidural abscess was diagnosed by magnetic resonance imaging and subsequently an emergency hemiaminectomy was performed. Physical examination and surgery did not show evidence of bacterial spread into the subarachnoid space.

CONCLUSION

Epidural abscess formation after CSE may increase the risk of bacterial spread into the subarachnoid space. In this case spontaneous exudation and surgical drainage of abscess material may have prevented intrathecal infection. Rapid diagnosis and treatment of an epidural abscess appears particularly essential after CSE to prevent neurological sequelae.

Intravenous regional anesthesia. Evaluation of 4 different additives to prilocaine

Intravenous regional anesthesia (IVRA) is an effective method of producing anesthesia of the extremities. Disadvantages are the rapid loss of anesthesia after the deflation of the tourniquet and the rapid development of postoperative pain. This study compared the effect of four different additives to prilocaine with saline on the development of a complete sensory block, on the return of sensory function after deflation of the tourniquet and on the development of postoperative pain after IVRA for minor orthopedic surgery of the arm. Seventy-five patients, ASA class 1 or 2, were randomly divided into 5 groups. All patients received 30 ml. of prilocaine 1%, together with 5 ml. of additive. In group 1, the additive was saline, in group 2 bupivacaine 0.25%, in group 3 clonidine 150 micrograms in saline, in group 4 sufentanil 25 micrograms in saline and in group 5 tenoxicam 20 mg. The development of a complete sensory block proved significantly faster in the patients receiving sufentanil (4.8 min.) as compared to plain prilocaine (7.5 min.). The return of the sensory function was comparable for all groups. Postoperative pain scores were significantly better in the clonidine and tenoxicam groups.

[Mechanisms of action of intravenous immunoglobulins]

Intravenous immunoglobulins (IVIG) are now used to treat various diseases, including autoimmune diseases, systemic inflammatory diseases, allografts and for replacement therapy in the case of IgG deficiency. Only in some of the indications has the efficacy of this treatment been confirmed in large-scale studies. Also, in many cases the modes of action remain unclear. Principally, the following therapeutic strategies can be differentiated: Replacement treatment, blocking of the effector molecules, influencing of the cellular and humoral limbs of the immune defence system and interaction with cytokines. In certain CNS diseases, displacement of pathological immunoglobulins may be involved. It would be desirable to acquire more detailed knowledge about modes of action with the aim of using IVIG with greater specificity in the future.