[Superparamagnetic iron oxide particles: what value has the T1 effect in the MR diagnosis of focal liver lesions?]. / Superparamagnetische Eisenoxidpartikel: Welchen Stellenwert hat der T1-Effekt für die MR-Diagnostik fokaler Leberläsionen?

PURPOSE: To evaluate the T1 effect of superparamagnetic iron oxide (SPIO) in MR imaging of focal hepatic lesions. METHODS: 21 patients with 34 liver lesions (18 benign) were examined before and immediately after infusion of SPIO particles (Endorem) with a T1-weighted GRE- and SE sequence and a double echo SE sequence at 1.5T. Changes of lesion signal intensity and contrast-to-noise (C/N) ratio were measured in addition to a qualitative analysis of changes in liver vessel signal. RESULTS: In all cases a marked increase of liver vessel signal intensity was observed on T1-weighted images after SPIO infusion. In contrast to malignant lesions, haemangiomas and adenomas showed significant signal changes (p < 0.05) on T1-and T2-weighted images. Highest signal changes were achieved for haemangiomas on T1-GRE images (+80%) followed by T1-SE (+41%) and T2-SE (-42%). Malignant liver lesions exhibited highest C/Ns on T2-weighted postcontrast images. CONCLUSION: The T1-effect of Endorem offers no benefits in respect of detectability of malignant liver lesions. However, it is helpful in characterising haemangiomas and their differentiation from liver tumours.

[Flow contrast behavior in fast MR angiography with an ECG-triggered, slice-selective inversion recovery turbo-FLASH technique]. / Verhalten des Flusskontrastes bei schneller MR-Angiographie mit einer EKG-getriggerten, schichtselektiven Inversion-recovery-Turbo-FLASH-Technik.

PURPOSE: To optimise and evaluate fast "inflow"-based contrast-prepared gradient-echo magnetic resonance angiography (MRA) of blood vessels with pulsatile flow. MATERIAL AND METHOD: We used a standard 2-D Turbo-FLASH sequence with an acquisition time of 0.9 s and a slice-selective hyperbolic secant inversion (SSIR) pulse for contrast preparation. Trigger delay and inversion time were systematically varied. RESULTS: Abdominal blood vessels of volunteers showed high signal intensity compared to stationary tissue without pulsatile artifacts. However, depending on cardiac cycle and inversion time, venous vessels in particular exhibited a periodic signal drop by maximum 70% of the peak value. Using optimised parameters SSIR turbo-FLASH images of patients could be obtained with high flow contrast between normal and pathological structures. CONCLUSION: With ECG triggering SSIR Turbo-FLASH MRA enables fast imaging of pulsatile vessels with optimised flow contrast.

[Detectability of focal liver lesions: comparison of MRI at 1.5 T and dynamic spiral CT]. / Erkennbarkeit fokaler Leberläsionen: Vergleich von MRT bei 1,5 T und dynamischer Spiral-CT.

PURPOSE: To compare dynamic spiral CT with MR imaging in the detectability of focal liver lesions. MATERIAL AND METHODS: Thirty-one patients with 62 focal liver lesions (27 benign) were evaluated retrospectively. Dynamic spiral CT scans were compared with T1- and T2- weighted spin-echo (SE) sequences and in part with multi slice 2-D-FLASH and single-shot slice-selective inversion recovery Turbo-FLASH sequences at 1.5 T. RESULTS: Dynamic spiral CT detected 89% of all lesions and was superior to each sequence alone (56-70%), and also to MRI overall (79%) regardless of lesion size, localization, and histology. However, statistical significance (p < 0.05) was only found for the differences between CT and the T1-weighted SE sequence. CONCLUSION: Compared to conventional SE and GE MR imaging sequences, dynamic spiral CT scanning seems to be more effective in the detection of focal liver lesions.

[Lemierre's post-tonsillitis sepsis with meningitis and intravascular consumption coagulopathy as complication of infectious mononucleosis with pansinusitis]. / Postangina-Sepsis Lemierre mit Meningitis und intravasaler Verbrauchskoagulopathie als Komplikation einer infektiösen Mononukleose mit Pansinusitis.

HISTORY AND CLINICAL FINDINGS: 24 days after the onset of infectious mononucleosis, clinically and serologically confirmed, an otherwise healthy 18-year-old schoolboy developed a fulminant septicaemia with acute meningitis and loss of consciousness, consumptive coagulopathy and acute renal failure. INVESTIGATIONS: Computed tomography demonstrated pansinusitis. Lumbar puncture produced purulent cerebrospinal fluid with 11,500 cells/microliters, predominantly granulocytes, protein 205 mg/dl, glucose 19 mg/dl, indicating bacterial meningitis. The suspected diagnosis of posttonsillitis septicaemia (Lemierre's syndrome) was confirmed by repeated demonstration of fusiform gram-negative bacteria in anaerobic blood cultures, identified as Fusobacterium necrophorum. Anaerobic CSF culture grew Prevotella bivia of the Bacteroidaceae family. TREATMENT AND COURSE: Both the consumptive coagulopathy and the renal failure were successfully treated and the patient's condition stabilized. The sinuses were surgically drained under high doses of piperacillin/sulbactam and chloramphenicol. Despite the sensitivity of the cultured bacteria to the administered antibiotics the septic temperature continued, but disappeared within 4 days of metronidazole having been added. After 5 weeks of antibiotic treatment, three of them in an intensive care unit, the patient was discharged in good general condition. CONCLUSION: This case illustrates that severe septicaemia caused by rare bacteria may follow an attack of infectious mononucleosis which had taken an uncomplicated course.

Dynamic Gd-enhanced MR imaging of hepatic hemangioma: is high temporal resolution requisite for characterization?

We assessed the value of high temporal resolution in the dynamic characterization of hepatic hemangioma with use of magnetization-prepared gradient-echo (MP-GRE) imaging. Single-level inversion recovery incremental flip angle MP-GRE images were obtained in 26 patients with 34 hemangiomas before and at a repetition rate of 30 images/min after injection of Gd-DTPA without breath-holding. Enhancement patterns and temporal changes thereof were analyzed. Hemangiomas were categorized as small ( < 2.0 cm), medium (2.0-5.0 cm), and large ( > 5 cm) lesions. Classic early peripheral nodular enhancement (PNE) with progressive hyperintense fill-in was observed in 31 lesions (91%). Two of 10 small and 1 of 20 medium lesions showed complete fill-in within 10 s, and three small and one medium lesions within 45 s after the onset of PNE. In no cases of hemangioma was immediate homogenous hyperintensity observed without preceding PNE. In conclusion, temporal resolution of less than 10 s is a prerequisite for confident dynamic characterization of some hemangiomas, predominantly small hemangiomas.

Gadopentetate-dimeglumine-enhanced MR imaging of osteonecrosis and osteochondritis dissecans of the elbow: initial experience.

Magnetic resonance imaging (MRI) was performed on seven patients with aseptic osteonecrosis (n = 4) and osteochondritis dissecans (OCD; n = 3) of the elbow. Precontrast MRI was superior to plain radiographs, which did not show any abnormality in three cases of osteonecrosis. On gadopentetate-dimeglumine-enhanced T1-weighted images, which were obtained in three patients with osteonecrosis and three patients with OCD, all cases of osteonecrosis demonstrated homogeneous enhancement of the lesions. All cases of OCD were diagnosed on plain radiographs. On MRI one showed significant enhancement of the loose body. In another case an incompletely enhancing loose body was surrounded by a diffusely enhancing region. In the third patient only a small marginal enhancement of the defect was observed. Our results suggest that MRI can improve the accuracy in diagnosis of aseptic osteonecrosis of the elbow. The use of gadopentetate dimeglumine allows the viability of the lesions or the loose bodies to be demonstrated and reparative tissue to be detected.

Gadolinium-enhanced T1-weighted versus T2-weighted imaging of scrotal disorders: is there an indication for MR imaging?

To evaluate the use of gadopentetate dimeglumine in magnetic resonance (MR) imaging of scrotal disorders, the clinical, ultrasound, and MR imaging data of 29 patients (age range, 19-75 years) with various intra- and extratesticular disorders were retrospectively analyzed. T1- and T2-weighted spin-echo images (T1-T2 group) were compared with T1-weighted spin-echo images before and after intravenous administration of gadopentetate dimeglumine (T1-Gd group). A receiver operating characteristic (ROC) analysis of the findings was undertaken. Better contrast between tumor and parenchyma and a clearer demonstration of the tunica albuginea were noted in the T1-T2 group (although not of diagnostic relevance). ROC analysis revealed no differences between the two imaging groups in the diagnosis of tumor, trauma, hydrocele, or hemorrhage; however, epididymitis was diagnosed more easily with contrast enhancement (0.8834 vs 0.7759, P = .04) and the diagnosis of orchitis was expressed more strongly (0.8221 vs 0.7184, P = .17). Four of the five observers were more confident in making the diagnosis with contrast enhancement. With MR imaging, the diagnosis was correctly suggested in three patients in whom clinical and ultrasound data were inconclusive. Gadolinium-enhanced MR imaging gives additional information in scrotal disorders and facilitates diagnosis. It may be helpful when findings at physical examination and ultrasound differ and when plain T1- and T2-weighted images are equivocal.

[The MR morphology of hemangiomas and lymphangiomas of the peripheral soft issues--a correlation with angiography and histology]. / MR-Morphologie von Hämangiomen und Lymphangiomen der peripheren Weichteile--Korrelation mit Angiographie und Histologie.

A retrospective analysis of the morphology and signal behaviour of T1, proton and T2-weighted spin-echo sequences has been carried out on 21 haemangiomas and 2 lymphangiomas of the peripheral soft tissues which had been examined by MRT. In 11 cases the diagnosis was confirmed histologically and in 12 by angiography. The majority of haemangiomas (19 cases) and both lymphangiomas showed hyperintense signals on T2-weighted spin-echo sequences; 2 lesions did not conform to this behaviour. MRT was a sensitive method for demonstrating vessels with high flow velocities so that it was possible to distinguish high flow haemangiomas by MRT. Apart from one thrombosed haemangioma, all 9 haemangiomas examined with iv Gd-DTPA showed homogeneous contrast uptake except for vessels with high flow velocities. One lymphangioma examined with iv Gd-DTPA was characterised by non-homogeneous contrast uptake.

Mn-DPDP in MR imaging of pancreatic adenocarcinoma: initial clinical experience.

Manganese (II) N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'-bis(phosphate) (DPDP) was tested as a contrast agent for magnetic resonance imaging of pancreatic adenocarcinoma in 15 patients. At enhanced T1-weighted spin-echo (SE) and enhanced T1-weighted gradient-echo (GRE) imaging, statistically significant increases in signal-to-noise ratio (S/N) for the pancreas (21% and 92%, respectively) and contrast-to-noise ratio (C/N) (91% and 209%, respectively) were found. The C/N at enhanced T1-weighted SE imaging was superior to that at unenhanced imaging, including T2-weighted SE imaging (P = .001). Subjective image analysis showed that delineation of the pancreas and pancreatic tumors was clearly improved (P = .05) on enhanced T1-weighted SE and GRE images compared with on unenhanced T1- and T2-weighted images. The liver enhanced 19% at T1-weighted SE imaging and 90% at T1-weighted GRE imaging. There was a significantly higher S/N increase in hepatic parenchyma than in pancreatic tissue at enhanced T1-weighted GRE imaging (P = .0026) but not at enhanced T1-weighted SE imaging.

[Dynamic inversion recovery snapshot FLASH MRT of focal nodular hyperplasia of the liver]. / Dynamische Inversion-Recovery-Snapshot-FLASH-MRT der fokal nodulären Hyperplasie der Leber.

11 lesions of focal nodular hyperplasia (FNH) in 6 patients were studied by means of dynamic snapshot-FLASH MRI before and after bolus injection of Gd-DTPA. In addition, plain snapshot-FLASH images were compared with T1- and T2-weighted spin-echo (SE) images and with T1-weighted breathhold-FLASH images. Highest FNH-liver signal-difference-to-noise ratios were obtained with snapshot-FLASH followed by T2-SE. In all patients contrast-enhanced serial snapshot-FLASH demonstrated reliably the typical haemodynamic appearance of FNH known from dynamic computed tomography. Because of its high intrinsic lesion-liver contrast and high time-resolution dynamic snapshot-FLASH MRI may facilitate differential diagnosis of hepatic tumours.

Transdiaphragmatic leakage of ascites in cirrhotic patients: evaluation with ultrafast gradient echo MR imaging and intraperitoneal contrast enhancement.

The utility of intraperitoneal instillation of Gd-DTPA and ultrafast MR imaging in the diagnosis of transdiaphragmatic leakage of ascites was assessed in two cirrhotic patients with right-sided pleural effusion. Contrast-enhanced serial snapshot-FLASH reliably demonstrated the communication between the peritoneal and the pleural cavities in both patients. In one case, a right-sided diaphragmatic defect could be exactly localized.

Incremental flip angle snapshot FLASH MRI of hepatic lesions: improvement of signal-to-noise and contrast.

Incremental flip angle (IFA) snapshot fast low angle shot (FLASH) is a new modification of inversion recovery snapshot FLASH MR imaging. The method changes the flip angle incrementally from low to high during data acquisition and was applied in the evaluation of 16 focal hepatic lesions in 10 patients. Sequence comparisons were performed with a fixed flip angle inversion recovery snapshot FLASH sequence (standard), a T1- and T2-weighted spin-echo (SE) sequence, and a T1-weighted breath-hold FLASH sequence. Whereas snapshot FLASH images in both pulse sequences were free from physiological motion artifacts, SE and FLASH images showed respiratory artifacts in some patients. Quantitative analysis of IFA snapshot FLASH images at low hepatic and low lesion signal revealed both superior lesion-liver signal-difference-to-noise ratio (SD/N) and superior contrast compared with standard snapshot FLASH without additional artifacts. Unless motion artifacts were evident, SE and FLASH images showed a higher anatomic resolution but lower SD/N and lower contrast than IFA snapshot images. Because of its superior SD/N and contrast, IFA snapshot FLASH will likely widen the application of fast MR imaging techniques.

[Radiographic examination of injuries in children. Clinical and legal considerations about indications]. / Röntgenuntersuchung bei Traumen im Kindesalter. Klinische und juristische Uberlegung bei der Indikationsstellung.

X-ray films of the skeleton obtained after trauma in 1,386 children and adolescents (until the end of their 18th year) were analysed retrospectively. Among a total of 2,006 examinations 354 fractures were diagnosed, an average diagnostic yield of 17.2%. Classifying the results by skeletal region, X-ray films of the skull were the most frequently requested examination (29.7%), but fractures were diagnosed in only 2.2%. On the other hand, X-rays of the lower arm provided the highest fracture yield, at 54.9%, followed by the shoulder with 47.7%.- In view of the large discrepancy between clinical suspicion and radiological confirmation of fractures, X-ray examinations should be undertaken in case of trivial injuries in children only if strictly indicated. Although the doctor is legally bound to detailed documentation of each case, this does not necessarily imply that he must perform an X-ray.

[Pulpous hamartoma of the spleen. Imaging by CT and MRT]. / Pulpöses Hamartom der Milz. Darstellung in der CT und MRT.

A rare case of a symptomatic splenic hamartoma is presented. Its appearance on both unenhanced and enhanced computed tomography and fast-scan magnetic resonance imaging is demonstrated.

[Ultrafast pelvimetry using Snapshot-FLASH-MRT--a comparison with the Spinecho and FLASH techniques]. / Ultraschnelle Pelvimetrie mittels Snapshot-FLASH-MRT--Vergleich mit der Spinecho- und FLASH-Technik.

Pelvimetry by means of snapshot-FLASH-MRI was carried out during the last trimester in 20 pregnant women. In 10 cases the results were compared with conventional spin-echo and FLASH-MRI. Snapshot-FLASH-MRI resulted in identical measurements but in addition provided images free from motion artifacts with good contrast of bone and soft tissue structures. The reduction in acquisition time resulted in pelvimetry in a few seconds. The total examination time and comfort for the patient were thereby improved.

Hepatic focal nodular hyperplasia: diagnosis by ultrafast Gd-DTPA enhanced FLASH MR.

The utility of gadolinium-enhanced ultrafast MR imaging in the diagnosis of focal nodular hyperplasia (FNH) of the liver was assessed in one patient. Contrast-enhanced serial snapshot-FLASH with a frequency of 30 images/min demonstrated the typical hemodynamic appearance of FNH known from CT studies.