Mixed reality for teaching catheter placement to medical students: a randomized single-blinded, prospective trial

BACKGROUND

Cost-effective methods to facilitate practical medical education are in high demand and the "mixed-reality" (MR) technology seems suitable to provide students with instructions when learning a new practical task. To evaluate a step-by-step mixed reality (MR) guidance system for instructing a practical medical procedure, we conducted a randomized, single-blinded prospective trial on medical students learning bladder catheter placement.

METHODS

We enrolled 164 medical students. Students were randomized into 2 groups and received instructions on how to perform bladder catheter placement on a male catheterization training model. One group (107 students) were given their instructions by an instructor, while the other group (57 students) were instructed via an MR guidance system using a Microsoft HoloLens. Both groups did hands on training. A standardized questionnaire covering previous knowledge, interest in modern technologies and a self-evaluation was filled out. In addition, students were asked to evaluate the system's usability. We assessed both groups's learning outcome via a standardized OSCE (objective structured clinical examination).

RESULTS

Our evaluation of the learning outcome revealed an average point value of 19.96 ± 2,42 for the control group and 21.49 ± 2.27 for the MR group - the MR group's result was significantly better (p = 0.00). The self-evaluations revealed no difference between groups, however, the control group gave higher ratings when evaluating the quality of instructions. The MR system's assessment showed less usability, with a cumulative SUS (system usability scale) score of 56.6 (lower half) as well as a cumulative score of 24.2 ± 7.3 (n = 52) out of 100 in the NASA task load index.

CONCLUSIONS

MR is a promising tool for instructing practical skills, and has the potential to enable superior learning outcomes. Advances in MR technology are necessary to improve the usability of current systems.

TRIAL REGISTRATION

German Clinical Trial Register ID: DRKS00013186.

Ureteric avulsion caused by lumbar exostosis

A 72-year-old woman sustained a ureteric avulsion following circulatory collapse at home. Urosonographic imaging revealed hydronephrosis at the left kidney, and abdominal emergency computed tomography showed some fluid around it. Left retrograde pyelography proved ureteral disruption at the level of the ureteropelvic junction (UPJ). Immediate open surgery was performed to restore ureteropelvic continuity. Correct and early diagnosis of UPJ transsection is difficult under emergency service conditions and lack of symptoms. With the rapid increase in the aging population, the presence of degenerative exostoses will increase, and its exclusive pathomechanism and pattern of injury might be seen more frequently in emergency care. Trauma specialists should be aware of this pathology.

Sonographic long-term study: paediatric growth charts for single kidneys

AIMS

To explore the clinical course of children with "single kidney" (defined as either a solitary or single functioning kidney) with reference to renal function (glomerular filtration rate (GFR) and proteinuria), body height and particularly sonomorphological features.

PATIENTS AND METHODS

This retrospective monocentric study evaluated 119 children with a solitary or single functioning kidney (>90% unilateral function on isotope scan) between 1997 and 2007. Patients were followed for 6.3 years (median, range 1-17) and had at least three renal ultrasound examinations (median 8). During recruitment six children were identified with chronic kidney disease (CKD) stage III or worse. These patients were analysed separately.

RESULTS

The aetiology of "single kidney" was attributed to contralateral multicystic dysplastic kidney (26%), tumournephrectomy (24%), renal agenesis (18%), hypo/dysplasia (11%) and obstructive or refluxive uropathy (18%). Irrespective of aetiology, the sonographic dimensions of "single kidneys" were in the upper range of normal paired kidneys and showed adequate growth. Compensatory renal hypertrophy (defined as >95% CI on two or more recent measurements) occurred in a third of patients. All six patients with CKD and GFR less than 60 ml/minute per 1.73 m(2) had pathological sonomorphology of their "single kidney" with inadequate renal growth (6/6), abnormal echogenicity (5/6), hypo/dysplasia (5/6). In addition, proteinuria (5/6) and short stature (3/6) were found.

CONCLUSIONS

New reference centiles were generated to assess renal size of "single kidneys" in paediatric patients. These charts will facilitate counselling of patients and parents. Further evidence for a benign clinical course of children with "single kidney" and absent additional pathology of the remnant kidney is presented.

[Polyhydramnios, prematurity, dystrophy, polyuria, constipation, nephrocalcinosis and renal tumor: presentation of a classic tubulopathy]

BACKGROUND

A diagnostic workup of a renal mass will rarely lead to the diagnosis of a tubulopathy. We would like to stress the importance of taking a detailed history and of evaluating these findings in the context of the clinical symptoms.

CASE REPORT

A 3 year old boy with a renal mass, diagnosed due to urinary tract infection, was referred to exclude renal malignancy. Detailed history revealed polyuria and polydipsia in a child with preterm delivery due to polyhydramnios. These symptoms, together with poor thriving are highly suggestive of a neonatal form of Bartter syndrome. This diagnosis was substantiated by ultrasound findings of nephrocalcinosis and urolithiasis due to hypercalciuria and a renal abscess. Detection of mutations in the KCNJ1-gene confirmed the diagnosis. After unilateral nephrectomy for acute destructive nephritis and under medication with indomethacin and potassium citrate the patient is now thriving well.

CONCLUSION

Renal masses suspicious of malignancy may distract from a hereditary tubulopathy. Typical clinical history and presentation with prematurity, polyhydramnios, polyuria, poor thriving and urolithiasis requires diagnostic evaluation of tubular function since routine laboratory tests and urinary dip stick may be normal. Unrecognized, neonatal Bartter syndrome may lead to severe complications including loss of kidney function.

[Left flank tumor of fluctuating size in a 5-week-old boy: perirenal urinoma caused by urethral valves]

BACKGROUND

Flank swelling and pseudotumors of the kidney are unusual manifestations of obstructive uropathies in small children. Our case illustrates typical problems and briefly reviews management options.

CASE REPORT

A 5-week-old boy presented with a large, palpable urinoma due to posterior urethral valves. Sonography and voiding cystourethrogram led to the diagnosis and immediate suprapubic transcutaneous urinary diversion was performed. However, the urinoma did not resolve. Thus, in addition to suprapubic urinary diversion, indirect drainage - instead of percutaneous puncture - was performed by retrograde insertion of a double-J catheter. Urethral valves were resected 4 weeks later and follow-up demonstrated an uneventful further development with normal renal function as assessed by regular ultrasound studies, a repeat cystourethrogram and a renal scan.

CONCLUSION

Perirenal urinomas may be the first symptom in patients with posterior urethral valves. Drainage via double-J stenting offers a promising alternative to percutaneous puncture. A renoprotective "pop-off" mechanism by which intrarenal pressure may be relieved is discussed.

Intraoral wound closure with tissue-engineered mucosa: new perspectives for urethra reconstruction with buccal mucosa grafts

In urethra reconstruction, the creation of a new urethra from a free oral mucosa graft is an established surgical technique. The oral mucosa is removed at the same time that the urethra reconstruction procedure is performed. Depending on the size of graft required, the intraoral wound is closed primarily or left to heal secondarily. The latter method limits this technique by leading to scars or strictures, which have a negative impact on the condition of the intraoral soft tissue. Therefore, in this study, a pilot study involving 12 patients, tissue-engineered mucosa was tested for covering intraoral defects to avoid the drawbacks mentioned above. For mucosa tissue-graft engineering, a biopsy sample 2 to 4 mm in diameter was removed from the hard palate approximately 4 weeks before the urethra reconstruction procedure was to be performed. In addition, 30 ml of autogenous serum was extracted from a venous whole-blood sample. The primary cultures were incubated in Dulbecco modified Eagle's medium and nutrient factor F 12 (Gibco Co., Eggenstein, Germany), containing the usual additives and autogenous serum. After a period of 3 weeks, subcultivation was performed to engineer mucosa transplants consisting of several layers of keratinocytes on a support foil. After thorough intraoperative blood coagulation had occurred, the cultured mucosa graft on the carrier foil was applied on the wound surface and fixed by single sutures. Additionally, the cultured mucosa graft was covered for 8 to 10 days by an intraoral dressing, which was also fixed onto the wound surface by single suture loops. It is possible to perform primary intraoral wound closure with tissue-engineered mucosa to cover defect sizes as large as 11.0 x 4.0 cm. This new method provides a better prospect for both urethra reconstruction and the reconstruction of intraoral tissue defects. The number and size of intraoral scars and strictures are diminished. This is of special interest for the reconstruction of the functional unit oral cavity, including soft tissue and cosmetic conditions (e.g., in case of prosthetic rehabilitation). In comparison to primary wound closure with local tissue, the technique presented in this study reduces the severity of postoperative pain and allows faster rehabilitation in patients because of a better wound-healing process. Furthermore, better mobility of intraoral soft tissue structures is achieved.

Fetotoxicity and teratogenesis of SWL treatment in the rabbit

The potential effects of extracorporeal application of shockwaves on an embryo or fetus were explored in an animal model. In experimental Series A, the fetuses of 30 gravid rabbits were exposed to piezoelectrically induced and sonographically guided shockwaves on Day 25 or 20 of gestation under technical conditions corresponding to extracorporeal lithotripsy in humans. Fetotoxicity was examined by abdominal section 24 hours or 9 days later, and immediate/intermediate damage was assessed (resorptions, viability, gross injuries, and microscopic lesions of the target and neighboring fetuses). In series B, the kidneys of an additional 28 gravid rabbits (including a control group) were exposed to the same shockwave treatment on Day 11 of gestation in order to investigate indirect embryotoxic effects, including teratogenic potency. One day before the expected birth, the maternal kidneys, uteri, and adjacent organs were examined for lesions, and the 156 offspring were assessed for embryolethal, embryonoxious, or teratogenic sequelae. Shockwave targeting of the cranium, thorax, abdomen, or placenta was usually lethal to the fetuses. When the uterine wall or the space between two fetuses was targeted, the fetuses suffered from superficial hematoma, as was found in the surrounding soft tissues within a radius of 1.5 cm. Fetuses outside this region were vital and free of lesions. Shockwave treatment of the maternal kidney resulted in renal petechial hemorrhage or subcapsular hematoma. However, statistically significant embryotoxic or teratogenetic effects could be demonstrated neither from maternal data (resorptions) nor from fetal findings (body measurements, vitality test, inner organs, skeletal deformities). When using a piezoelectric lithotripter with a small focus of high energy, lesions of a fetus are to be expected only when it is located in or close to the focus. It seems that embryotoxic or teratogenic sequelae do not occur when shockwaves are focused outside the uterus. Nonetheless, this preliminary research does not justify clinical use of extracorporeal shockwave lithotripsy in pregnant humans.

Once-daily fleroxacin versus twice-daily ciprofloxacin in the treatment of complicated urinary tract infections

PURPOSE

We compared the efficacy and safety of once-daily fleroxacin and twice-daily ciprofloxacin in patients with complicated urinary tract infections.

MATERIALS AND METHODS

Using a prospective, open, randomized, multicenter study design, 133 patients (67 fleroxacin, 66 ciprofloxacin) were treated with doses of either 200 mg. of fleroxacin once daily or 250 mg. of ciprofloxacin twice daily in phase 1. In phase 2, 211 patients (103 fleroxacin, 108 ciprofloxacin) received 400 mg. of fleroxacin once daily or 500 mg. of ciprofloxacin twice a day.

RESULTS

In phase 1, bacteriological efficacy was excellent only against sensitive pathogens, such as Escherichia coli (84% with fleroxacin, 88% with ciprofloxacin), but high failure rates were observed in infections caused by Pseudomonas species (56% with fleroxacin, 67% with ciprofloxacin) and gram-positive organisms (52% with fleroxacin, 67% with ciprofloxacin). In phase 2, bacteriological overall success rate was 88% in the fleroxacin group and 84% in the ciprofloxacin group. Clinical overall success was observed in more than 90% of patients in both groups (94% with fleroxacin, 93% with ciprofloxacin). No statistically significant differences between the drugs were observed in efficacy during phase 2, including a 4 to-6-week followup. Tolerance was also similar for fleroxacin and ciprofloxacin, with about 20% of patients reporting adverse events.

CONCLUSIONS

The results suggest that both fleroxacin and ciprofloxacin are safe and effective for the treatment of complicated urinary tract infections at the higher doses used in phase 2, with fleroxacin offering the advantage of a once-daily dosing regimen. Lower doses of fleroxacin (200 mg. once daily) should only be used to treat urinary tract infections caused by gram-negative organisms with minimum inhibiting concentrations of less than 0.5 mg./l.

Endoscopic treatment of reflux by subureteric collagen injection: critical review of 5 years' experience

In the past decade, subureteric endoscopic injection of Teflon or collagen has been propagated as a safe and successful treatment for vesicoureteral reflux. In our center, from 1990 through 1995, 118 children and 5 adults with reflux and recurrent urinary tract infections were injected with cross-linked bovine collagen in an open, prospective study. Efficacy and safety were assessed 6 and 12 months after injection, and long-term (> or =3 years) results were available in 78 cases. The overall success rate was 58% (64% of ureteral units) free from reflux at 12 months and 54% (58%) after 3 years. Analysis of anatomic, urodynamic, and technical features showed the grade of reflux to be the best predictor of success or failure. When only primary low- and middle-grade reflux, without concomitant anatomic disorders, is considered, the long-term success rate rose to 69% (74% of ureteral units). In conclusion, subureteric collagen injection cannot ultimately replace the highly effective surgical reimplantation. However, the procedure offers a minimally invasive alternative in selected cases of mild reflux when conservative management is inadequate.

Ureteral xanthine calculus and aberrant umbilical artery causing ureteral obstruction

A 30-month-old girl presented with gastrointestinal symptoms and a febrile urinary tract infection. Sonographic and radiographic imaging demonstrated left hydronephrosis due to a radiolucent ureteral stone. Surgical exploration identified an aberrant, patent left umbilical artery causing ureteral obstruction. Stone and urine analyses revealed hereditary xanthinuria that had not previously been recognized in this child and her family.

Subureteral collagen injection versus antireflux surgery in primary vesico-ureteral reflux grade III

Endoscopic subureteral collagen injection (SCIN) was performed in 24 girls and 5 boys (mean/range: 3.2/0.7-12.2 years) with primary grade III vesicoureteral reflux. Clinical outcome was compared to 20 girls and 6 boys treated by antireflux surgery (mean/range: 3.0/0.2-9.4 years). forty-one ureters were treated by endoscopy, 37 by surgery. Patients were followed for 12 months. SCIN was not associated with severe persistent complications. No reflux was detected immediately after SCIN. After 6 months recurrent grade II reflux was present in 1 (4%) surgically treated patient and in 12/29 (41%) patients treated by collagen injection. This corresponded to a recurrence rate of 1/37 (3%) of ureters following surgery and 15/41 (37%) following SCIN. 8/15 refluxing ureters after collagen showed decreased reflux grade (two grade I, six grade II). After 12 months 24/26 (92%) patients with antireflux surgery remained free of urinary tract infections as compared to 25/29 (86%) children following endoscopy. Following SCIN, 4/29 (14%) patients required secondary antireflux surgery because of recurrent urinary tract infections.

CONCLUSION

On the basis of this study endoscopic SCIN appears to be safe in children. It is less effective than surgery with regard to elimination of primary grade II reflux. However, clinical success rate is comparable to surgery with regard to the frequency of recurrent urinary tract infections after the procedure. This may be due to the reduction of refluxing urine volume in those patients who showed recurrence of reflux after collagen injection.

Salmonella enteritidis orchitis in a 10-week-old boy

Extraintestinal manifestations of salmonellosis in paediatric patients are found predominantly in infants less than three months of age. Genital involvement is a rare complication. We present a short review of the literature and describe the case of a 10-week-old boy suffering from severe diarrhoea, who presented with a swelling of the right testicle after six days of illness. He underwent surgery on suspicion of testicular torsion, whereby orchitis was diagnosed. Salmonella enteritidis was cultured from the intraoperative swab. All cultures from blood, CSF and urine remained sterile. We conclude that orchitis must be taken into consideration as an extraintestinal complication of enteric salmonellosis and as a differential diagnosis of testicular torsion. In addition, we wish to emphasize that any infant less than three months of age with suspected or proven salmonellosis, should receive early antibiotic treatment.

Correlation of ultrasound and renal scintigraphy in children with unilateral hydronephrosis in primary workup

Ultrasound accurately detects hydronephrosis in infants and children, while nuclear medicine techniques quantify relative renal function in addition to characterizing the urodynamic relevance of hydronephrosis. This prospective study was undertaken to examine the relationship between ultrasound morphological findings and relative renal function, quantified with dynamic 99mtechnetium mercaptotriacetylglycine imaging, in the initial diagnostic workup of children with unilateral hydronephrosis. The ultrasound grade of hydronephrosis and relative renal function ipsilateral to the hydronephrosis were inversely related, indicating that with more severe hydronephrosis ultrasound fails to estimate the potential reduction of relative kidney function. Because renal function is not necessarily affected by hydronephrosis, renal scintigraphy is indicated to assess the functional status of hydronephrotic kidneys.

Dopamine receptor modulation of noradrenaline release by carmoxirole in human cortical kidney slices

The effect of the dopamine D2-receptor agonist carmoxirole on noradrenaline release was investigated in human and rat cortical kidney slices. After preincubation with 3H-noradrenaline, the slices were electrically stimulated at 5 Hz in superfusion chambers, and the stimulation-induced (S-I) outflow of radioactivity was taken as the index of noradrenaline release. In human but not in rat cortical kidney slices, carmoxirole (0.03 microM) inhibited the S-I outflow of radioactivity. Carmoxirole (0.3 microM) also failed to inhibit the S-I outflow of radioactivity from human kidney slices. When alpha-adrenoceptors were blocked by the non-selective alpha-adrenoceptor antagonist phentolamine (1 microM), carmoxirole (0.03 microM, 0.3 microM) inhibited S-I outflow to a similar extent. The inhibitory effect of carmoxirole (0.03 microM) was prevented by the D2-receptor antagonist (-)-sulpiride (10 microM) but not by the D1-receptor antagonist SCH 23390 (1 microM) in human kidney slices. Phentolamine (1 microM) by itself induced a five-fold greater enhancement of the S-I outflow of radioactivity in rat than in human cortical kidney slices. The data suggest that activation of prejunctional D2-receptors by carmoxirole inhibits noradrenaline release from human renal sympathetic nerves. Carmoxirole in higher concentrations (0.3 microM) blocks inhibitory prejunctional alpha-autoreceptors, which seems to mask the inhibitory D2-receptor mediated effect. The different effects of phentolamine and carmoxirole in human and rat kidney may indicate a difference of the prejunctional alpha-autoreceptor mechanism in the two species.

Dopamine DA2-receptor activation inhibits noradrenaline release in human kidney slices

Dopamine receptor modulation of noradrenaline release from renal sympathetic nerves was investigated. Human kidney slices were incubated with 3H-noradrenaline, placed into superfusion chambers between two platinum electrodes and field-stimulated at 5 Hz. The slices accumulated radioactivity. Pretreatment of the kidney slices with 6-hydroxy-dopamine (1.2 mM) prior to the 3H-noradrenaline incubation reduced the accumulation of radioactivity. The stimulation induced (S-I) outflow of radioactivity was mainly composed of intact 3H-noradrenaline. The sodium channel blocker tetrodotoxin (1 microM), 6-hydroxy-dopamine pretreatment and omission of calcium from the superfusion solution abolished S-I outflow of radioactivity. The DA1-receptor agonist fenoldopam (SKF 82526; 0.01 and 0.1 microM) did not alter but fenoldopam (1 microM) increased S-I outflow of radioactivity. However, in the presence of either the non-selective alpha-adrenoceptor antagonist phentolamine (1 microM) or the selective alpha 2-adrenoceptor antagonist idazoxan (1 microM) fenoldopam (1 microM) had no effect. The DA2-receptor agonist quinpirole (LY 171555; 1 microM) inhibited S-I outflow of radioactivity, an effect blocked by the selective DA2-receptor antagonists S(-)-sulpiride (10 microM) and domperidone (0.3 microM) but unaltered either by the DA1-receptor antagonist SCH 23390 (1 microM) or by phentolamine (1 microM). The alpha 2-adrenoceptor agonist UK 14304 (0.1 microM) inhibited S-I outflow of radioactivity, and this effect was blocked by phentolamine (1 microM) and idazoxan (1 microM) but unaltered by S(-)-sulpiride (10 microM). Phentolamine and idazoxan, in contrast to S(-)-sulpiride, domperidone and SCH 23390, enhanced S-I outflow of radioactivity by themselves.(ABSTRACT TRUNCATED AT 250 WORDS)

[The treatment of urolithiasis. State of the art]

Extracorporeal shock wave lithotripsy, percutaneous nephrolitholapaxy and retrograde ureterorenoscopy are modern urological procedures which have almost completely replaced open surgery of urolithiasis in the last decade. A review of techniques, management of clinical problems and differential indications is presented as a state of the art of these new treatment modalities in urinary stone disease.

[RARE-MR urography: a rapid MR tomographic imaging procedure for the diagnosis of urinary tract malformations in childhood]

RARE-MR urography (so called "water-pictures") is a fast MR imaging technique that selectively depicts fluid without contrast application. Acquisition time is 6.4 s per slice with 1 excitation, or 23 s per slice with 2 averages respectively. From Sept. 1989 to April 1990 24 children with anomalies of the urinary tract have been examined each by RARE MR urography and one T1-weighted spin-echo sequence. Independent of excretory function, the technique can show dilated calices and renal pelvis, pelviureteric obstruction, renal duplication, and megaureter. However, it cannot distinguish between vesicoureteric reflux and obstructive megaureter. Our first results suggest that RARE MR urography combined with ultrasound, reflux cystography and isotope nephrography, can replace excretory urography in certain circumstances--or at least postpone it to the preoperative phase.

RARE-MR-urography in the diagnosis of upper urinary tract abnormalities in children

RARE-MR-urography (Rapid Acquisition with Relaxation Enhancement) is a fast MR imaging technique (6.4 s/acquisition) that selectively depicts fluid by heavy T2-weighting. From 9/1989 to 11/1990, RARE-MR urograms were prospectively evaluated in the diagnosis of upper urinary tract abnormalities in 55 children. The method is performed in several planes and combined with a coronal, T1-weighted spin-echo sequence. Forty out of 42 kidneys with dilated renal pelvis, and 21 out of 24 dilated ureters were identified, only the mildly dilated ones were missed. Even in non-functioning kidneys the urinary tract was clearly depicted by RARE-MR-urography. However, no differentiation could be made with this technique between vesicoureteral reflux and non-refluxing dilatation of ureter and/or renal pelvis. All 19 pelviureteric obstructions and all eight renal duplications with a dilated segment were identified. RARE-MR-urography is a new tool for diagnosing urinary tract abnormalities in children without having to employ ionizing radiation, contrast media, or general anesthesia. A dilated urinary tract can be shown in one image displaying the entire urinary system, similar to excretory urography. The technique is presently not able to provide the information of voiding cystourethrography or renal scintigraphy, nor is it as easy to perform as ultrasound. However, in certain cases it may replace excretory urography.

[Initial clinical experiences with RARE-MR urography]

Potentials and limitations of a new, facultative non-tomographic Fast-Imaging sequence "RARE-MR-Urography" are presented. Its results in urological diseases are discussed on the basis of a pilot study of 35 patients. The images (4 s-32 s acquisition time) are extremely T2-weighted and display unbounded free water (urine). They reveal valuable information, not available with ultrasound or conventional radiology without application of contrast agents in the presence of urine retention. S/N problems reduce the accuracy of this method if the urinary tract contains only small amounts of urine.

[Clinical study of the effectiveness and tolerance of norfloxacin in the therapy of complicated urinary tract infections and in long-term prevention of recurrent urinary tract infections]

The efficacy and tolerance of norfloxacin in the treatment of complicated urinary tract infections and in low dose long-term prophylaxis over six months for recurrent UTI were investigated in 60 and 27 patients, respectively. In the prophylaxis group, compliance with medication was controlled weekly using Mecur BT. Five to nine days after treatment, the urine was sterile in 50 out of the 60 patients treated (83.3%); relapse occurred in six patients and was associated with development of resistance in two. Four patients suffered re-infection within the study period. Failure of treatment was closely related to persisting complicating factors in the urinary tract. The overall tolerance of norfloxacin was satisfactory. However, there was one severe allergic reaction. During the total 391 weeks of low dose long-term prophylaxis given to 27 patients, only one break-through infection occurred. Yet compliance studies proved that antimicrobial activity was present in the urines of less than 50% of the patients. During prophylaxis, the rate of infection was reduced from three to four to 0.13 to 0.05 infections/patient/year. There was no development of resistance in the isolates from these patients. Only two adverse reactions were observed.

[RARE-MR urography: a fast nontomographic imaging procedure for demonstrating the efferent urinary pathways using nuclear magnetic resonance]

RARE-MR-Urography is a new fast data acquisition technique for magnetic resonance imaging. As a non-tomographic approach to the morphology of the urinary system, image information is similar to intravenous X-ray urography. As the sequence results in a heavily T2-weighted image displaying aqueous fluids, application of contrast agents is not necessary. Image quality is demonstrated by an exemplary case. Basic technical details and possible indications are discussed.

[Ceftizoxime concentration in blood, muscle, and kidney tissue]

The pharmacokinetic properties of ceftizoxime, a new beta-lactamase-resistant cephalosporin, were investigated in 27 patients following perioperative antimicrobial prophylaxis. 2 g of ceftizoxime were injected before surgery and the concentrations measured in serum, muscle and renal tissue over a period of 30 min to 7 h. The pharmacokinetic data indicated high and long-lasting concentrations of ceftizoxime, especially in the renal tissue; this makes the drug ideal for the treatment of complicated urinary tract infections with obstruction and involvement of the renal tissue, provided the bacteria present are sensitive. The administration of 2 g i. v. every 12 h should be sufficient. In view of the high and long-lasting concentrations, it should be possible to treat uncomplicated urinary tract infections with a single dose of 2 g every 24 h. However, Enterococci, Bacteroides and Pseudomonas aeruginosa are not sufficiently sensitive to ceftizoxime and a combination with an aminoglycoside is thus indicated in the treatment of high-risk patients in the absence of bacteriological tests.