[Importance of magnetic resonance imaging/ultrasound-guided fusion biopsy for the detection and monitoring of prostate cancer]. / Stellenwert der MRT/Ultraschall-Fusionsbiopsie für die Detektion und Verlaufskontrolle des Prostatakarzinoms.

The use of multiparametric magnetic resonance imaging (mpMRI) is becoming increasingly more important for the primary diagnostics of prostate cancer (PCa) and for monitoring under active surveillance. Current studies confirmed that the use of mpMRI can increase the detection of clinically significant PCa and reduce the detection rate of insignificant PCa as well as the rate of unnecessary biopsies. The information from mpMRI can be cognitively used for in-bore biopsy and using fusion biopsy systems. There are no clear recommendations on the access approach for fusion biopsy (e. g. transrectal or perineal), whereby higher rates of rectal bleeding and infections have been described for transrectal access compared to perineal access. The increasing rate of antibiotic resistance as well as restricted indications for the use of quinolones are a major challenge for transrectal biopsy.

Reversible cerebral hyperperfusion syndrome after stenting of the carotid artery - two case reports.

Hyperperfusion syndrome can complicate carotid revascularization, be it endarterectomy or carotid artery stenting (CAS). Although extensive effort has been devoted to reducing the incidence of ischemic stroke complicating CAS, little is known about the incidence, etiology, and prevention strategies for hyperperfusion following CAS. We report two cases (female patients 72 and 81 years) presenting severe internal carotid stenosis (> 90%), who underwent presurgical and therapeutic intervention with CAS. Both patients developed hyperperfusion symptoms at 2 hours and at 30 minutes, respectively, following stenting, in both cases unilateral hyperperfusion was CCT confirmed. Case 1 was presenting with acute edema of the right hemisphere, case 2 with distended focal edema (left fronto-temporoparietally). Hyperperfusion syndrome and neurological symptoms retroceded in both cases (conservative therapy) and both patients returned to full activity (case 2 within 48 hours).

MR angiography versus color Doppler sonography in the evaluation of renal vessels and the inferior vena cava in abdominal masses of pediatric patients.

OBJECTIVE: Involvement of renal vessels and the inferior vena cava (IVC) plays a decisive role during operative planning for removal of abdominal masses in pediatric patients. Advantages and limitations of MR angiography and color Doppler sonography for determining these factors were evaluated. MATERIALS AND METHODS: MR angiography and color Doppler sonography were performed preoperatively in 42 neonates, infants, and children with abdominal masses and were compared with spin-echo MR imaging and with surgical findings. Variables evaluated were anatomic variants, vessel displacement, patency of vessels, collateral circulation, and intravascular tumor extension. Quality of vessel visualization was assessed in vessels not affected by tumor. RESULTS: In 88% of unaffected renal vessels, the entire vessel course could be visualized on MR angiography compared with 58% on color Doppler sonography and 43% on spin-echo MR imaging. In four of nine cases, color Doppler sonography revealed an accessory renal artery, whereas MR angiography revealed these variants in seven of nine cases. MR angiography showed 79% and color Doppler sonography 66% of displaced vessels. Unlike MR angiography, color Doppler sonography did not reveal five stenotic renal veins because they could not be completely imaged. In two cases, however, MR angiography falsely indicated an occlusion of the IVC, whereas color Doppler sonography showed residual flow. CONCLUSION: Anatomic variants, vessel displacement, collateral circulation, and neoplastic vessel infiltration were revealed more accurately by MR angiography than by color Doppler sonography. In cases in which patency of the IVC is unclear on MR angiography, color Doppler sonography should also be performed.

Dose and image quality of electron-beam CT compared with spiral CT.

RATIONALE AND OBJECTIVES: To examine dose and image quality of electron-beam CT (EBCT) with continuous volume scan versus spiral CT. METHODS: An EBCT scanner was compared with a spiral CT (SCT) scanner. Three phantoms were used to measure low-contrast resolution, high-contrast resolution, slice width, and dose. RESULTS: The EBCT scans showed 30% lower high-contrast resolution for most settings. The dose was comparable to that of spiral CT with 3 mm collimation and 76%/106% higher with EBCT for 1.5 mm/6 mm collimation. Low-contrast resolution was comparable to that of spiral CT using 3 mm collimation, slightly worse for 1.5 mm, and bad for 6 mm EBCT collimation (four times higher dose to reach comparable contrast-to-noise ratio). CONCLUSIONS: Significant restrictions were found using EBCT with continuous volume scan. The authors found that 3 mm collimation can yield acceptable high-contrast resolution and good low-contrast resolution compared with spiral CT. The use of 6 mm or 1.5 mm collimation needs to be restricted to selected cases.

Normative volumetric data of the developing hippocampus in children based on magnetic resonance imaging.

PURPOSE: To acquire normative data of the hippocampus and its postnatal growth in 50 children (age, 1 month to 15 years) without epilepsy. METHODS: Morphometry of the hippocampus was carried out by using a spoiled FLASH 3D sequence (sagittal orientation), whereas the volume of the brain was assessed with a T2-weighted spin-echo sequence (transverse orientation). The volume of the hippocampus and the brain was determined by following Cavalieri's principle. Growth curves of the brain and hippocampus were fitted to a nonlinear Boltzmann sigmoidal equation. RESULTS: Intra-/interobserver coefficient of variation was 2.0/4.9% for hippocampal volume measurements and 2.0/2.1% for brain volumetry. A significant difference in volume was noted between the right and left hippocampus (p < 0.001), with the right side being larger on average by 0.10 cc. Correlation coefficients of growth curves ranged between 0.71 and 0.94. Growth curves demonstrated a faster development of the hippocampus in girls. A steeper slope of hippocampal growth as compared with brain growth was found in girls, whereas in boys, the slope of brain growth was steeper. CONCLUSIONS: Our findings will be of help in evaluating vulnerable phases of the hippocampal formation with accelerated growth, thereby leading to a better understanding of the development of hippocampal sclerosis in early childhood.

The carpal ligaments in MR arthrography of the wrist: correlation with standard MRI and wrist arthroscopy.

We assessed the value of three-compartment magnetic resonance (MR) wrist arthrography in comparison with non-enhanced magnetic resonance imaging (MRI) for the evaluation of 13 individual wrist ligaments in 35 patients with refractory wrist pain. In 20 of these patients MR findings were correlated with the findings from multiportal wrist arthroscopy. For MR imaging (1.5-T magnet) a three-dimensional volume acquisition with a gradient-recalled echo sequence and 0.6-1.0 mm effective slice thickness was used. The delineation of individual wrist ligaments was rated as "good" in 10% of non-enhanced MR and 90% of MR arthrography images. Ligament evaluation was possible with high diagnostic confidence in 11% by non-enhanced MR imaging and 90% by MR arthrography. With wrist arthroscopy as the standard of reference, average sensitivities/specificities/accuracies for the diagnosis of full-thickness ligamentous defects were 0.81/0.75/0.77 for non-enhanced MR imaging and 0.97/0.96/0.96 for MR arthrography. Our findings suggest that MR arthrography is more accurate than standard MRI in delineating and evaluating the ligaments of the wrist.

Biomechanical analysis of stress distribution in the human temporomandibular-joint.

The positions of the head of the mandible, of the articular disc and the outline of the temporal surface are digitized from sagittal MRI-scans of the temporomandibular joint of a 32-year-old subject in 5 different positions of occlusion. The stress distribution in the joint is calculated on the basis of these data. For each position of the condyle, the momentary center of rotation in the head of the mandible and the tangent attached to the temporal surface are determined. The line connecting these two points indicates the direction of the resulting compressive force. Furthermore, the extension of the area available to the force transmission is estimated. By means of these parameters the stress distribution is calculated independently from the position. The analyses show that the temporomandibular joint is slightly eccentrically loaded in all positions. The increase of the stresses is in all cases oriented caudo-ventrally. The results are verified in an anatomical specimen of the articular tuberculum. The trabecular structures as well as the subchondral bone-lamella of the articular tuberculum are functionally adapted to the analyzed stress situations.

Radiation dose and image quality in spiral computed tomography: multicentre evaluation at six institutions.

The purpose of this study was to evaluate the correlation of radiation dose with image quality in spiral CT. Seven clinical protocols were measured in six different radiological departments provided with four different types of high specification spiral CT scanners. Central and surface absorbed doses were measured in acrylic. The practical CT dose index (PCTDI) was calculated for seven clinical examination protocols and one standardized protocol using identical parameters on four different spiral CT scanners with a dedicated ionization chamber inserted into PMMA phantoms. For low contrast measurements, a cylindrical three-dimensional (3D) phantom (different sized spheres of defined contrast) was used. Image noise was measured with a cylindrical water phantom and high contrast resolution with a Perspex hole phantom. Image quality phantoms were scanned using the parameters of the clinical protocols. Images were randomized, blinded and read by six radiologists (one from each institution). PCTDI values for four different scanners varied up to a factor between 1.5 (centre) and 2.2 (surface) for the standardized protocol. A greater degree of variation was observed for seven clinical examination protocols of the six radiological departments. For example, PCTDI varied up to a factor between 1.7 (cerebrum protocol) and 8.3 (abdomen paediatric protocol). Low contrast resolution correlates closely with dose. An improvement in detection from 8 mm to 4 mm sized spheres needs approximately a ten-fold increase in dose. Noise shows a moderate correlation with PCTDI. High contrast resolution of clinical protocols is independent of PCTDI within a certain range. Differences in modern CT scanner technology seem to be of less importance for radiation exposure than selection of protocol parameters in different radiological institutes. Future discussion on guidelines regarding optimal (patient adapted) tube current for clinical protocols is desirable.

[Dosimetry in conventional and spiral CT in 8 spiral CT scanners of the latest generation]. / Dosismessung für Einzelschicht- und Spiralmodus bei 8 Spiral-CT-Scannern der neuesten Generation.

PURPOSE: Measurement of scanner-dependent differences in PCTDI for conventional and spiral CT and evaluation of PCTDI/100 mAs in eight spiral CT scanners of the latest generation. METHODS: Central PCTDI was evaluated in a PMMA phantom for different scan lengths of conventional and spiral CT in four scanners. Central and peripheral PCTDI/100 mAs, average dose and the quotient between peripheral and central PCTDI/100 mAs were measured with a dedicated 10 cm ionisation chamber positioned within a PMMA phantom using the parameters of a standardised liver protocol and a high-resolution inner ear protocol for eight spiral CT scanners. RESULTS: Depending on scanner type and scan length PCTDI for the spiral mode is in a range between 11.3% higher and 4.3% lower than that for the conventional mode. PCTDI/100 mAs varies considerably between different CT scanners. For the standardised liver protocol PCTDI/100 mAs varies up to a factor of 2, for the inner ear protocol up to a factor of 4. CONCLUSION: Even in comparable modern CT scanners there are considerable protocol and scanner-dependent differences in PCTDI/100 mAs. The values for his own scanner should be known to each CT user so that he can develop a dose-optimised, patient and problem-orientated examination strategy.

Marinesco Sjögren syndrome with rhabdomyolysis. A new subtype of the disease.

Four children from two families with characteristics of Marinesco-Sjögren syndrome (congenital cataract, ataxia) are presented. All children had clinical and neurophysiological signs of a demyelinating polyneuropathy. Three of them developed acute rhabdomyolysis with marked weakness and CK levels of up to 40,000 U/I following a viral infection. In all children CK levels returned to normal within two weeks. Symptoms were recurrent in one of the children and resulted in a severe disability. In two other children recovery of motor function took about a month following the first attack. Metabolic disorders of the muscle were excluded by pathobiochemical examination of a muscle biopsy in one of the children. In conclusion, acute rhabdomyolysis can occur as a neuromuscular complication of Marinesco-Sjögren syndrome.

Prospective evaluation of MR arthrography performed with high-volume intraarticular saline enhancement in patients with recurrent anterior dislocations of the shoulder.

OBJECTIVE: The purpose of this study was to evaluate the accuracy of high-volume saline-enhanced MR arthrography in assessing the labrum, the ligaments, and the bony components of the glenohumeral joint. SUBJECTS AND METHODS: Forty-four patients with recurrent anterior dislocations of the shoulder underwent MR arthrography after intraarticular injection of 15-40 ml of saline solution. Two-dimensional fast low-angle shot and T1-weighted spin-echo sequences were prospectively evaluated by two observers. Anterior (Bankart) lesions, superior labral lesions extending from anterior to posterior, and Hill-Sachs lesions were diagnosed. Glenohumeral ligaments (GHLs) were identified and classified using a standard system. MR imaging results were compared with those of arthroscopy (n = 32) or open surgery (n = 12), either of which was the gold standard. RESULTS: Bankart lesions and superior labral lesions extending from anterior to posterior were revealed with a sensitivity of 93% and 89%, respectively, and a specificity of 80% and 89%, respectively. Diagnostic accuracy was 89% for both types of lesions. All six patients with bony Bankart lesions had high fat-marrow signal intensity within the fragment on T1-weighted MR images. For GHLs, MR imaging results and arthroscopy correlated in 25 of the 31 patients. In three patients all three GHLs were visible on MR imaging, but only two GHLs were detected with arthroscopy. In three patients two GHLs were detected on MR imaging but all three were visible on arthroscopy. Hill-Sachs lesions were revealed with a sensitivity of 95%, a specificity of 50%, and an accuracy of 81%. CONCLUSION: High-volume saline-enhanced MR arthrography is accurate in revealing the labrum, the ligaments, and the bony components of the glenohumeral joint Saline solution is inert and inexpensive, two advantages over gadopentetate dimeglumine.

[Performance of electron-beam CT: continuous-volume-scan compared to spiral CT]. / Abbildungseigenschaften der Elektronenstrahl-CT. Continuous-Volume-Scan im Vergleich zur Spiral-CT.

To compare patient dose and image quality of electron-beam-CT vs. spiral-CT by means of phantom measurements. An EBCT scanner (C-150 XP) and a spiral-CT scanner (GE HiSpeed Advantage) were used to scan three different phantoms. Administered dose, high contrast (HC) resolution, low contrast (LC) lesion detectability and the width of the radiation beams were measured. EBCT showed 25-35% lower HC resolution in comparison to spiral-CT. LC lesion detectability showed equivalent results for S/N vs. patient dose using 3 mm collimation with EBCT and spiral-CT, whereas spiral-CT was superior for 1.5 and 6 mm collimation. Dose measurements revealed a 2 fold higher patient dose using EBCT with 1.5 mm or 6 mm collimation compared to spiral-CT using equivalent scan parameters. No differences were seen using 3 mm collimation. Differences were due to insufficient beamside collimation of the EBCT. The use of EBCT with 6 mm collimation should be avoided, because of impaired performance. Using 3 mm collimation, EBCT showed comparable performance like state of the art spiral-CT despite lower HC resolution.

The scapholunate interosseous ligament in MR arthrography of the wrist: correlation with non-enhanced MRI and wrist arthroscopy.

OBJECTIVE: To compare three-compartment MR wrist arthrography with non-enhanced MRI in correlation with wrist arthroscopy, and to evaluate the potential of MR arthrography for consistently visualizing all parts of the scapholunate interosseous ligament of the wrist (SLIL) and exactly diagnosing the site and extent of SLIL defects. DESIGN AND PATIENTS: In 41 patients with wrist pain (34 patients with wrist pain for more than 6 months) plain radiographs, stress views, non-enhanced MRI and three-compartment MR arthrography were done within 2 h of each other, using three-dimensional volume acquisition (0.6-1.0 mm effective slice thickness) with a gradient-recalled echo sequence and a 1.5-T magnet. The MR arthrography findings were compared with the findings from non-enhanced MRI and correlated with the arthroscopic findings in all patients. RESULTS: The dorsal, central and palmar segments of the SLIL could be delineated exactly by MR arthrography in 95% of the patients; with non-enhanced MRI only 28% of SLIL segments were seen consistently. Demonstration of SLIL defects was possible with high diagnostic confidence in 42% of SLIL segments by non-enhanced MRI and in 94% by MR arthrography. With wrist arthroscopy as the standard of reference, sensitivity and specificity values for SLIL perforations were 52%/34% for non-enhanced MRI and 90%/87% for MR arthrography. CONCLUSIONS: MR arthrography, using three-dimensional volume acquisition with thin slices (0.6-1.0 mm), combines the advantages of three-compartment arthrography and non-enhanced MRI. It shows the precise location and magnitude of ligamentous defects of all parts of the SLIL, correlates well with wrist arthroscopy and has potential implications for diagnosis and treatment planning.

[A proposal for the MR staging of early rheumatoid arthritis in the metacarpophalangeal and proximal interphalangeal joints]. / Vorschlag einer MR-Stadieneinteilung der frühen rheumatoiden Arthritis an den Metakarpophalangeal- und proximalen Interphalangealgelenken.

PURPOSE: MRI can demonstrate pathology of joint disease in the early course of rheumatoid arthritis prior to destructions seen on conventional radiographs. In a prospective study, we tried to develop a systematical classification of joint pathology demonstrated by MRI, which would be essential for scoring the course of the disease. PATIENTS AND METHOD: Metacarpophalangeal and interphalangeal joints of 48 patients suffering from early rheumatoid arthritis (mean disease duration: 6.4 months) were evaluated by MRI using a high-resolution transmitter-receiver coil. Examinations included 2 mm sliced T2-, T1- and gadolinium enhanced T1-SE sequences in coronal and axial orientation. In consideration of pathological findings on MRI and histopathogenetical pathways of destruction in rheumatoid arthritis a MR-score (0-5) was established. RESULTS: This allowed to score each joint examined: score 0 (normal) in 47.8%/49.5%, score 1 in 35.5%/50.5%, score 2 in 4.2%/0%, score 3 in 10.8%/0%, score 4 in 1.5%/0% of the metacarpophalangeal/interphalangeal joints, respectively. CONCLUSIONS: Using the MR-score a relative individual destruction number can be calculated, which may be used to follow up patients in the early course of rheumatoid arthritis (e.g. drug therapy studies). The presented MR scoring system has to be evaluated further in longitudinal studies and must be correlated to radiographical and clinical findings.

Local muscle flaps of the second and third interosseus space for the treatment of osteomyelitis in the central metacarpal region.

Both experimental and clinical studies showed that muscle flap transposition is a reliable tool in treating chronic infections of the bone. The major advantage of local muscle flaps is the treatment with well perfused autogenous tissue without using any implants. The primary closure of the operation site and the cure of infection within four weeks allow a short immobilisation time. Nevertheless, the loss of muscle function with a possible functional and aesthetic defect in the donor site has to be accepted. The first dorsal interosseus muscle and the abductor digiti minimi muscle have been used successfully for the treatment of metacarpal osteomyelitis. Osteomyelitis in the central metacarpal bones cannot be treated with these techniques, because of their limited range. We present the muscles of the second and third interosseus space for local pedicled muscle flap transfer. The arterial network in this interosseus spaces and the vascularisation of the dorsal and palmar interosseus muscles allow to harvest muscle flaps with either proximal or distal pedicle. The loss of interosseus muscles in the second and third interosseus space is tolerable from a functional and esthetic point of view. Operative techniques are shown for the elevation of dorsal and palmar interosseus muscle flaps. Two cases of osteomyelitis in the central metacarpal bones, which were treated successfully with the new local interosseus muscle flaps, are reported.