[The vascular patient--diagnosis and minimally invasive therapy. Which technique for what illness?]

The non-invasive imaging modalities, color coded duplex sonography (CCDS), magnetic resonance tomography (MRT), and computed tomography (CT), have pushed conventional angiography out of most diagnostic fields. The experienced user will achieve fast, reliable answers with CCDS in dedicated clinical settings. MRT as well as CT are concurring imaging modalities for the most appropriate diagnostic answer. Not only pure image quality, but also patient management, and availability play a major role. Catheter based angiography will in the future still play a role in mesenteric ischemia (non occlusive disease) and for imaging of very small vessel pathology, e.g. on panarteritis nodosa. At the moment, peripheral leg run-offs are still best performed with conventional angiography, nevertheless, MR as well as CT seem to have the ability to perform diagnostic procedures. Ongoing studies will allow a solid judgement in the near future. The true value of catheter angiography is in the direct assessment, planning, and performance of interventional procedures, e.g. catheter based obliteration or revascularization. Implantation of stent devices and a whole range of different mechanical and pharmacological revascularization procedures have improved the interventional management of vascular stenoses and occlusions. The interventional radiologist is treating physician in the classical sense in this setting. Acute bleeding episodes, e.g. in the brain, thorax, abdomen, or pelvis, are best imaged with computed tomography. Conventional angiography still plays a major diagnostic and therapeutic role in bleeding into preformed cavities, such as the bile ducts or the intestine. In this setting, all available information including CT scans should be valued. For complex therapeutic regimens in oncology or in pure palliative situations, angiographic diagnosis followed by embolization and/or ablation therapy is established.

[MRI in chronic inflammatory bowel disease]

Chronic inflammatory bowel disease is diagnosed and monitored by the combination of colonoscopy and small bowel enteroklysis. Magnetic resonance imaging has become the gold standard for the imaging of perirectal and pelvic fistulas. With the advent of ultrafast MRI small and large bowel imaging has become highly attractive and is being advocated more and more in the diagnostic work up of inflammatory bowel disease. Imaging protocols include fast T1-weighted gradient echo and T2-weighted TSE sequences and oral or rectal bowel distension. Furthermore, dedicated imaging protocols are based on breath-hold imaging under pharmacological bowel paralysis and gastrointestinal MR contrast agents (Hydro-MRI). High diagnostic accuracy can be achieved in Crohn's disease with special reference to the pattern of disease, depth of inflammation, mesenteric reaction, sinus tract depiction and formation of abscess. In ulcerative colitis, the mucosa-related inflammation causes significantly less bowel wall thickening compared to Crohn's disease. Therefore with MRI, the extent of inflammatory changes is always underestimated compared to colonoscopy. According to our experience in more than 200 patients as well as the results in other centers, Hydro-MRI possesses the potential to replace enteroklysis in the diagnosis of chronic inflammatory bowel disease and most of the follow-up colonoscopies in Crohn's disease. Further technical improvements in 3D imaging will allow interactive postprocessing of the MR data.

[Ocular injuries and triage after the bombing attack on the United States embassy in Nairobi (Kenya)]

BACKGROUND

As a result of the terrorist bombings of the United States Embassies in Daressalam (Tansania) and Nairobi (Kenya) on August 7, 1998, over 200 people were killed. 5000 persons were injured severely. The purpose of this article is to provide a review of our experiences in the evaluation and treatment of patients with multiple simultaneous ocular injuries sustained in the Nairobi attack.

PATIENTS AND METHODS

We treated eight survivors of the assault, four of them with extremely severe eye injuries. A three-tiered system of triage developed. The first level occurred on scene, in which minor injuries were treated locally and more severe injuries were transported by aeromedical evacuation to Landstuhl Regional Medical Center (LMRC), in Germany among other locations. Surgical exploration of all patients arriving at LRMC was performed and surgical repair was undertaken when appropriate and technically possible. Patients requiring vitreoretinal surgery were transferred either to Saarland University Eye Hospital, Homburg, Germany, or Walter Reed Army Medical Center, Washington, DC.

RESULTS

Only one eye required enucleation, due to an almost complete extrusion of the retina. It was possible to stabilize even severely injured eyes with multiple intraocular foreign bodies.

CONCLUSIONS

Modern microsurgical techniques such as temporary keratoprothesis, perforating keratoplasty, and pars plana vitrectomy can now save eyes and often allow restoration of usuable visual acuity where this once have been deemed impossible.

[Recurrent Clostridium difficile enterocolitis]

Pseudomembranous enterocolitis generally occurs after antibiotic treatment. The standard treatment is oral metronidazol or vancomycin. Nevertheless, relapses of Clostridium difficile enterocolitis are observed in 10-25% of cases. Factors associated with recurrences include endogenous reinfection by spore formation, selective IgG1 or IgA deficiency or infection with mutated strains of Clostridium difficile. Recurrent Clostridium difficile enterocolitis may be treated with repeat oral vancomycin combined with Sacchoromyces boulardii, with intravenous immunoglobulin for severe colitis.

[Rational diagnostic strategy for tuberculous lymphadenitis]

OBJECTIVES

To examine the clinical, radiographic and laboratory findings in patients with tuberculous lymphadenitis and to analyse the investigational strategies which lead to the diagnosis of tuberculous lymphadenitis.

METHODS

Retrospective study including 16 HIV-negative patients at the Cantonal Hospital, Winterthur with tuberculous lymphadenitis diagnosed between 1994 and 1999.

RESULTS

The majority of patients presented with local symptoms and without signs of severe systemic disease. All the PPD skin tests performed were positive. Cultures for M. tuberculosis were more often positive using fine-needle aspiration than surgical biopsy. We found a lack of systematic diagnostic strategy.

CONCLUSIONS

We suggest a standardised investigation procedure. When tuberculous lymphadenitis is suspected, the first diagnostic step consists of a PPD skin test and fine-needle aspiration for acid fast smear, mycobacterial culture and cytology. Surgical biopsy should be done if the cytological and mycobacteriological results of fine-needle aspiration are not diagnostic.

Spontaneous regression of intrahepatic lesions mimicking metastatic disease

This is a case report of a 53-year-old male with chronic hepatitic C infection presenting with weight loss and elevated liver function tests. Repeated ultrasonography, computed tomography and magnet resonance imaging showed multiple intrahepatic lesions suggestive of metastatic disease. Repeated ultrasound-guided biopsies from the lesions as well as from the adjacent normal appearing liver tissue revealed no malignancy but showed inflammation and significant fibrotic tissue, consistent with chronic hepatitis C. 2 years after the first admission liver function tests were all within the normal range and remained so until today. Computed tomography at that time showed complete remission of all intrahepatic lesions. The exact diagnosis remained elusive but the rare case of reversible focal fibrosis is the most likely cause of these spontaneously regressive lesions.

Primary stability of press-fit-implanted osteochondral grafts. Influence of graft size, repeated insertion, and harvesting technique

The aim of this study was to evaluate the fixation strength of press-fit-implanted osteochondral grafts with respect to graft size (length and diameter), the effect of repeated insertion after pullout, and harvesting technique. Experiments were performed using the Osteochondral Autograft Transfer System on porcine femoral condyles. Failure loads of 10-mm-long grafts (mean, 47 N) were significantly lower than failure loads of 15-mm-long grafts (mean, 93 N) and 20-mm-long grafts (mean, 110 N) (all grafts, 11 mm in diameter). Reinsertion of the 15-mm-long grafts after initial pullout resulted in a significant reduction of failure loads (mean, 93 N versus 44 N). Failure loads of 8-mm-diameter grafts (mean, 41 N) were significantly lower than those of 11-mm-diameter grafts (mean, 92 N) (all 15 mm long). Levering of the tubular chisel during graft harvest significantly decreased press-fit stability as compared with simple turning of the chisel (mean, 32 N versus 52 N) (8-mm diameter and 15-mm length). These results suggest that primary fixation strength of press-fit-inserted osteochondral grafts depends on the size of the grafts and that repeated pullout and reinsertion of grafts as well as a nonoptimal harvesting technique (levering) will reduce primary stability.

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.

Incidence of irregular cycles among Mayan women who reported having regular cycles: implications for fertility awareness methods

Despite the low contraceptive prevalence among the Mayan population of Guatemala, past research has found interest in natural methods. A calendar rhythm method with a simple blanket rule would appear to be preferable to more complicated methods. Under a blanket rule, the number of days of abstinence is predetermined and all couples are instructed to abstain during the same interval of the menstrual cycle. However, regular menstrual cycles may be key to successful practice of a calendar method. A database of 880 cycles of 301 women of the Guatemalan highlands was analyzed to determine the length and regularity of menstrual cycles in this population.

Computer-based organisation and documentation in orthopaedics: 5 year's experience

In the orthopedic department of the University Hospital Homburg/Saar, we use since 1993 a computer-based system for clinics organisation and documentation of operations. Hardware consists of DOS/Windows PC's in a Novell-network. Our software is a combination of datbase-system for managing patient-data and a special coding program for ICD and IKPM-digits. Our experience shows that computer assisted clinic-management is an effective tool to help the surgeon in planning and documentation. Until now, we used the system for 31 500 patients and 8500 operations. A flexible software can meet the requirements both of the surgeons and administration. Moreover, in the University hospital Homburg/Saar, the different departments are linked by an Intranet with connection to other scientific networks and the Internet.

[Computer-based organization and documentation in orthopedics. A 5-year experience]

In the orthopedic department of the University Hospital Homburg/Saar, we use since 1993 a computer-based system for clinics organisation and documentation of operations. Hardware consists of DOS/Windows PC's in a Novell-network. Our software is a combination of database-system for managing patient-data and a special coding program for ICD and IKPM-digits. Our experience shows that computer assisted clinic-management is an effective tool to help the surgeon in planning and documentation. Until now, we used the system for 31,500 patients and 8500 operations. A flexible software can meet the requirements both of the surgeons and administration. Moreover, in the University hospital Homburg/Saar, the different departments are linked by an Intranet with connection to other scientific networks and the Internet.

Resulting tensile forces in the human bone-patellar tendon-bone graft: direct force measurement in vitro

The objective of this study was to measure the resultant force in the human bone-patellar tendon-bone graft after reconstruction of the anterior cruciate ligament under various conditions in vitro. Seven fresh-frozen cadaver lower extremities were used. Force measurement was made with a quartz force transducer mounted in a specially designed load cell. The effect of passive extension movement, quadriceps pull, varus torque, and valgus torque on the resultant force in the ligament were investigated. Passive extension of the joint generated a rapid increase of force in the graft between 30 degrees and 0 degrees of flexion, reaching its maximum (128+/-25 N) at full extension. When quadriceps pull was applied to extend the joint, resultant force increased at 50 degrees of flexion and reached its maximum (219+/-25 N) at full extension. Additional resistance applied to the level of the ankle joint generated an additional load of the graft. Increase of forces in the ligament resulted from both varus and valgus applied moments.

Bilateral fracture of the sacrum associated with pregnancy: a case report

We describe a 33-year-old woman with a bilateral fracture of the sacrum associated with pregnancy. Dual-energy X-ray absorptiometry of the lumbar spine and femoral neck showed normal bone mineral density, whereas bilateral osteopenic areas in the massae laterales were demonstrated by the initial CT-scan. The question remains whether the correct diagnosis is so-called insufficiency fracture due to transient osteoporosis of the sacrum associated with pregnancy or so-called fatigue fracture due to unaccustomed stress related to rapid and excessive weight gain in the last trimester of pregnancy.

Generating and influencing Torsades de Pointes--like polymorphic ventricular tachycardia in isolated guinea pig hearts

Torsades de Pointes (TdP) is a polymorphic ventricular arrhythmia which can degenerate into ventricular fibrillation. The most typical symptom of TdP is the ECG morphology where QRS complexes seem to rotate around the isoelectric baseline. Bradycardia and delayed repolarization are regarded as pathophysiologic predispositions. For better understanding of the pathophysiology and the evaluation of therapeutic or proarrhythmic potential of drugs, a functional experimental model is needed. In the present study, an experimental model of polymorphic tachyarrhythmias taken as TdP equivalents in isolated guinea pig hearts was developed. The hearts were perfused by the Langendorff technique. Bradycardia was induced by dissection of the sinus node, and prolongation of the QT interval by infusion of two inhibitors of the sodium channel inactivation, veratridine and DPI 201-106. TdP equivalents were triggered reproducibly by application of electrical single stimuli at the end of the T wave. Experiments with different concentrations of the channel active substances alone and in combination, with different perfusion times and mode of electrical stimulation (single pulse versus train stimulation), showed the highest incidence for TdP equivalents by means of an initial 30 min long infusion of 0.5 microM each veratridine and DPI 201-106 in combination with electrical single stimuli. After finishing the infusion with the channel active substances but still with lasting effects from them. TdP equivalents were triggered repeatedly in five of six experiments. The reasons for this increased TdP susceptibility after finishing the infusion are not known. In a separate series of six similarly arranged experiments, the incidence for TdP equivalents could be decreased from 83% to 12.5% (p < 0.001) by increasing the concentration of magnesium in the perfusate from 1.17 to 5.0 mM. With these experiments, the clinically known therapeutic effect of magnesium suppressing TdP could be demonstrated in an in vitro model for the first time. The results suggest that this model could be used as a base for further studies of clinical relevant drugs, especially antiarrhythmic agents, to obtain hints of possible risks of proarrhythmic effects or of suitability for therapeutic use at TdP attacks.

[Pneumococcal vaccination--yes or no?]

Invasive pneumococcal infections, defined as demonstration of Streptococcus pneumoniae in blood cultures or CSF, are frequent and associated with high mortality in risk groups. Risk groups are the over-65s, individuals with anatomic or functional asplenia, immunosuppressed patients, patients with haemotological neoplasias and HIV-infected subjects, as well as, in general, al sufferers from chronic cardiopulmonary disease, diabetics and patients with severe renal failure or nephrotic syndrome. The 23valent polysaccharide vaccine produces a reliable immune response in children aged over 2 years and adults. The immune response is diminished in severely immunocompromised subjects and in the elderly. Numerous clinical studies provide evidence of the effectiveness of pneumococcal vaccination in the he prevention of invasive pneumococcal infection. Pneumococcal vaccination is recommended for the above mentioned risk groups. It should be observed that for the group at most risk, i.e. heavily immunosuppressed and HIV-infected subjects, there are no convincing data on clinical effectiveness. Regarding non-bacteriaemic pneumococcal pneumonias there are only pointers to the possible usefulness of polysaccharide vaccines. Booster vaccination is not recommended by the manufacturers in view of the reportedly increased incidence of side effects. Studies show that side effects are not more frequent than with primary vaccination. A single revaccination is particularly indicated in status post splenectomy. The conjugate vaccines now under development will improve the efficacy of pneumococcal vaccination and will also be usable in children aged under 2 years.

[Digital mammography: experiences in its clinical application]

TARGET

In 1989 in the Cantonal Hospital of Lucerne conventional film-screen mammography was replaced by digital mammography. With the support of a retrospective study, it was checked whether or not digital mammography represents an equally valid diagnostic procedure in daily routine.

METHODS

1204 patients were examined using digital mammography. A reevaluation of these patients was carried out using clinical and radiological routine controls. Additionally a radiological and histological examination was performed in 127 cases in which excisional biopsies had been done, paying particular attention to detail perception.

RESULTS

The sensitivity of digital mammography achieved a total of 85%, whereas the accuracy was 81%. With additional use of ultrasound and galactography the sensitivity attained 91%. By reevaluation the sensitivity amounted to 87%, the accuracy remaining at 81%. The positive predictive value was especially high with 76% and 77%.

CONCLUSION

Digital mammography offers satisfactory diagnostic performance.

[Diagnostic imaging for therapy control of primary bone tumors]

Adjuvant chemotherapy has significantly improved the prognosis of patients with bone sarcomas. Preoperative diagnostic imaging of tumor response to such therapy has become a mainstay for the assessment of prognosis, planning of surgery and further treatment. During therapy, responding tumors show characteristic changes on conventional radiography, angiography, sonography, radionuclide studies, CT and MR. The usefulness and the limitations of each imaging modality in assessing response to therapy are reviewed. The diagnostic importance of specific changes such as tumor volume reduction, calcification and tumor vascularization is discussed.

Herpes simplex virus encephalitis: cranial magnetic resonance imaging and neuropathology in a mouse model

We performed a long-term magnetic resonance imaging (MRI) study in a mouse model of herpes simplex virus encephalitis. Mice were infected with herpes simplex virus type 1 (HSV-1) strain F. A 1.5-T cranial MRI scanner with standard spin-echo sequences was used. Neuropathological studies included immunohistochemistry. The presence of HSV DNA in brain tissue was determined with a polymerase chain reaction assay. Clinical assessment was performed daily: within the first 2 weeks the animals were severely affected and recovered thereafter. MRI and histopathological abnormalities corresponded well. HSV DNA was detectable initially and at 6 months. Extent and severity of structural abnormalities increased at 6 months. MRI offers a new in vivo approach for the detection of structural changes in the disease course of experimental herpes simplex virus encephalitis.

[Multiple reader analysis for evaluation of functional MR mammography]

The diagnostic impact and reproducibility of the different methods used within the concept of functional MR-Mammography (FMRM) was assessed by a multi-reader-analysis. By four experienced readers, 100 histologically confirmed cases were evaluated in six different sessions. Per session, one of the following components was analyzed: clinical history (I), static MRM (II), color-coded projection images (III), time-signal curves of contrast enhancement within a large ROI (IV) and the strongest enhancing pixel (V) obtained from the histologically confirmed lesion and the complete FMRM reading (VI). The functional methods (IV-VI) revealed significantly (p < 0.05) higher specificities than the others (I-III). The highest reproducibility between the readers was observed for (IV) phi chi = 0.80, (V) phi chi = 0.76 and FMRM (VI) phi chi = 0.63. These three methods also presented the best ROC-curves and showed the highest complementarity with respect to the false positive classifications in x-ray mammography. FMRM is a reader independent, reproducible method. The analysis of the contrast enhancement time-intensity curves with high temporal resolution allows an improved differentiation of malignant and benign findings.

Low specificity of the bacterial index for the diagnosis of bacterial pneumonia by bronchoalveolar lavage

The bacterial index (BI) as defined by the sum of log10 colony-forming units (cfu) of microorganisms per milliliter of bronchoalveolar lavage (BAL) fluid, i.e., a multiplication of the single cfu/ml, has been used to distinguish between polymicrobial pneumonia (BI> or =5) and colonization (BI<5). Since many false-positive results are to be expected using this parameter, the diagnostic value of the BI was studied prospectively by obtaining bacteriologic cultures of BAL fluid in 165 consecutive unselected patients. In 27 cases the diagnosis of bacterial pneumonia was established on clinical criteria. In 133 patients pneumonia could be excluded, and in five patients the diagnosis remained unclear. Using a cut-off of > or = 10(5) cfu/ml BAL fluid, sensitivity and specificity for the diagnosis of pneumonia were 33% (9/27) and 99% (132/133), respectively. Sensitivity was mainly influenced by prior treatment with antibiotics, being 70% (7/10) in untreated and 12% (2/17) in treated patients. Applying the BI methodology at a cut-off of > or =5, however, resulted in an unacceptably high rate of 16 additional false-positive results, thus lowering the specificity to 87% (116/133; P<0.0001) while increasing the sensitivity to only 41% (11/27; P = 0.77). In conclusion, given the high rate of false-positive results, the methodology of the BI is of doubtful value for the diagnosis of bacterial pneumonia by BAL in an unselected patient group. By applying the absolute number of cfu/ml BAL fluid, however, positive bacteriologic cultures of BAL fluid are highly specific for the diagnosis of pneumonia. Their sensitivity is limited by previous antibiotic therapy.