[The MRT of malignant tumors of the oral cavity and oropharynx with frequency-selective and inversion-recovery fat-signal suppression]. / MRT maligner Tumoren der Mundhöhle und des Oropharynx mit frequenzselektiver und Inversion-Recovery-Fettsignalunterdrückung.

PURPOSE: Evaluation of frequency-selective fat saturation (FS) and Short-Tau-Inversion-Recovery (STIR) fat suppression (FU) in MRI of patients with malignant tumours of the oral cavity or oropharynx. METHODS: Twenty patients with biopsy-proven squamous cell carcinoma of the oral cavity or oropharynx were examined by MRI at 1.0 T. A T2-weighted TSE-sequence with and without STIR-FU and a T1-weighted SE-sequence with and without FS were compared in axial slices. RESULTS: STIR-FU was successful in all and FS in 29/33 (87.9%) of the examinations. When visualisation and delineation of tumours were ranked on a four-point scale (0-3), respective mean values for images without/with FU or FS of 1.9 and 2.6 for T2-TSE, 1.4 and 1.3 for T1-SE without contrast media administration (CM) and 2.0 and 2.5 with CM were found. Signal/noise-ratios were inferior with FU and FS, but the tumour/muscle intensity ratio in CM-T1-SE improved with FS. CONCLUSIONS: STIR-T2-TSE and FS-T1-SE with CM were most useful for MRI of carcinomas of the oral cavity and oropharynx.

[75-year-old patient with persistent abdominal complaints and vomiting during a cruise]. / 75-jährige Patientin mit persistierenden abdominellen Beschwerden und Erbrechen während einer Kreuzfahrt.

BACKGROUND: In elderly patients with gallstone disease, a gallstone ileus must be considered for unexplained abdominal pain. This is demonstrated in the following case report. CASE REPORT: A 75-year-old female patient presented with a 72-hour history of abdominal pain, nausea and vomiting. The patient's abdomen was mildly distended, although soft and nontender with bowel sounds present. Plain radiographs and ultrasound investigation of the abdomen were compatible with small bowel obstruction. To clarify the etiology, an abdominal computed tomography scan was obtained. These examinations disclosed air in the biliary tree, dilated small bowel and an impacted intraluminal abnormality in the terminal ileum compatible with a gallstone. Operative intervention confirmed the presence of a 3 cm obstructing calculus in the terminal ileum that was removed by an enterolithotomy. A two-step cholecystectomy and closure of the cholecystoduodenal fistula were performed 8 weeks later. The patient's recovery was uneventful. CONCLUSIONS: Although rare in a general population, gallstone ileus accounts for 25% of nonstrangulated small bowel obstructions in patients over the age of 65. The radiographic picture and ultrasound of small bowel obstruction and the presence of air in the biliary tree are suggestive for the diagnosis of a gallstone ileus. In our patient, the computed tomography and ultrasound findings confirmed the diagnosis and led to a prompt and directed surgical intervention. In patients with comorbid factors a two-step approach with enterolithotomy in a first and cholecystectomy in a second operation should be the therapeutic strategy of choice.

[Short tau inversion recovery fat suppression in T2-weighted turbo spin echo-MRI of malignancies of the mouth and oropharynx]. / Short-Tau-Inversion-Recovery-Fettsignalunterdrückung bei der T2-gewichteten Turbo-Spin-Echo-MRT von Malignomen in Mundhöhle und Oropharynx.

BACKGROUND: T1-weighted sequences before and after the application of contrast medium and T2-weighted sequences are used for magnetic resonance imaging of malignomas of the oral cavity and the oropharynx. The authors studied the utility of short tau inversion recovery fat suppression (STIR) in T2-weighted turbo spin echo sequences (TSE). METHODS: Twenty patients with malignomas of the oral cavity and oropharynx were examined on a 1.0 Tesla magnetom using T2-weighted TSE-sequences with and without STIR as well as T1-weighted spin echo sequences before and after the application of contrast medium. RESULTS: STIR was successfull in all patients. STIR worsened the signal-noise-ratio significantly, but improved tumor delineation compared to T2-TSE without fat suppression in 75% according to three different investigators. CONCLUSION: The STIR technique is beneficial for the progress in diagnostic imaging of cancer of the oral cavity and oropharynx.

[Acceptance of high field whole body MRI equipment, open MRI systems dedicated extremity scanners by patients]. / Akzeptanz von Hochfeld-Ganzkörper-MR-Geräten, offenem MR-System und dediziertem Extremitätenscanner durch die Patienten.

To our knowledge no comparative studies investigating patients' acceptance of different MR systems have been published. We therefore studied a number of subjective criteria to evaluate both patients' acceptance of and subjective conditions during magnetic resonance imaging (MRI) studies. MRI studies were performed using four separate systems. Two were conventional body MR systems operating at 1.0 or 1.5 Tesla, another was a 0.2 Tesla open whole-body MR system, and the last was a 0.2 Tesla MR system dedicated to the study of extremities. Forty patients for each MR system (total of 160 patients) participated in a standardized, written interview focusing on aspects of their subjective condition, including their perception and acceptance of different factors relevant to the study on respective MR systems. The patients' subjective condition and acceptance was predominantly positive for all MR systems. Differences between MR systems were noted with respect to noise, width of patient gantry, comfort of patient positioning and degree of well-being. Such differences, however, do not lend preference to the use of one particular type of MR system. Therefore, the choice of MR system should be based on the technical features required for the intended studies.

[Ultrasonography of veins]. / Ultraschalluntersuchungen der Venen.

PURPOSE: The high incidence of acute and chronic diseases of the venous system requires the application of reliable, non-invasive, low-cost methods in diagnosis and follow-up after therapy. MATERIAL AND METHODS: Current technology, principles of examination, and results of ultrasonography of the peripheral venous systems are reviewed. RESULTS: Since the mid 1980s, compression ultrasonography (US) has been introduced in the diagnosis of deep venous thrombosis. Doppler-US methods reach the hallmarks of venous imaging, particularly since the advent of color duplex US. In thrombosis, postthrombotic syndrome, and primary varicosis, color duplex US increasingly replaces the "gold standard" of phlebography as the imaging method of choice. Venous diseases of the neck, and of the upper and lower extremities are reliably recognized by color duplex US. New areas of application of Doppler and duplex-US include examinations of the venous system in patients in intensive care units, evaluation of transplanted organs, and the demonstration of blood flow in hemodialysis shunts. CONCLUSIONS: Color duplex US is useful in most imaging investigations of the peripheral veins. In view of cost development in the medical imaging sector, however, in which ultrasonography takes a major part, critical indication for the application of Doppler- and duplex-US in the diagnosis and follow-up of venous disease is out most importance.

[Initial results with MRI-controlled laser-induced interstitial thermotherapy of head and neck tumors]. / Erste Ergebnisse der MRT-gesteuerten laserinduzierten interstitiellen Thermotherapie von Kopf- und Halstumoren.

Laser-induced interstitial thermo-therapy (LITT) was introduced as a minimally invasive form of therapy for tumors in different anatomic regions. However, in the orofacial region, it has not been used so far for inoperable T4 carcinomas. Since vascular and neural structures are often close to the tumor or are even involved, online monitoring of LITT is necessary. The aim of our study was to establish a method of monitoring LITT with MRI (magnetic resonance imaging) in the orofacial region. Five patients with T4 carcinomas of the orofacial region underwent LITT under anesthesia. A 1.5 T whole-body imager with a circular polarized head coil was used. Before and after the intervention, the region of interest was studied using T1- and T2-weighted sequences in axial and coronal planes, with and without contrast enhancement (intravenous Gd-DTPA). Temperature distribution was monitored with a T1-weighted 2D-FLASH (fast low angle shot) sequence. The positioning of the optical fibers was monitored with MRI. Nd:YAG laser equipment was used for laser application. The necrosis was best seen on contrast-enhanced MRI. Immediately after LITT, the outcome could be determined by MRI. We proposed that MRI-guided LITT be used for neoplasms in the orofacial region at advanced stages.

[Value of fat signal suppression MRI pulse sequences for diagnosis of malignant tumors in the area of the head-neck]. / Wertigkeit der fettsignalunterdrückenden MRT-Pulssequenzen für die Diagnostik maligner Tumoren im Kopf-Hals-Bereich.

PURPOSE: Evaluation of frequency-selective fat saturation (FS) and short-tau inversion recovery (STIR) fat suppression (FU) in MRI of patients with malignant head and neck tumors. METHODS: Forty-five patients with biopsy-proven carcinomas of the extracranial head and neck were examined with MRI at 1.0 T. A T2-weighted TSE sequence with and without STIR-FU and a T1-weighted SE sequence with and without FS were compared in axial slices. RESULTS: STIR-FU was successful in all and FS in 85-88% of the head examinations (nasopharynx, sinuses, oropharynx, and oral cavity) and 33-46% of the neck examinations (hypopharynx and larynx). When visualization and delineation of tumors were ranked on a four-point scale (0-3), respective mean values for images with/without FU or FS were 2.6/1.9 for T2-TSE in all examinations, 2.2/1.7 (nasopharynx and sinuses) and 1.3/1.4-1.6 (oropharynx, oral cavity, hypopharynx, and larynx) for T1-SE without contrast media administration (CM) and 2.3/2.1 (nasopharynx and sinuses) and 2.4-2.5/1.9-2.0 (oropharynx, oral cavity, hypopharynx, and larynx) with CM. CONCLUSIONS: STIR-T2-TSE was a technically reliable pathfinder for localization and extension of both tumors and lymph nodes. FS-T1-SE was technically unreliable in examinations of the hypopharynx and larynx. With CM, FS-T1-SE was most useful for MRI of carcinomas of the oral cavity and oropharynx. In the nasopharynx and sinuses, T1-SE with CM and FS-T1-SE with or without CM were equal for tumor visualization and delineation.

[MRI monitoring before, during and after interstitial laser-induced hyperthermia of benign prostatic hyperplasia. Initial clinical experiences]. / MRT-Monitoring vor, während und nach der interstitiellen laserinduzierten Thermotherapie der benignen Prostatahyperplasie. Erste kliniscne Erfahrungen.

PURPOSE: To assess the clinical value of MRI in patients with benign prostatic hyperplasia (BPH) before, during, and after interstitial laser-induced thermotherapy (LITT) of the prostate. METHODS: Ten patients with symptomatic BPH had MRI examinations of the prostate 48 h before and after LITT. Online monitoring with MRI at 1.5 T of interstitial Nd:YAG laser energy deposition in the prostate was performed in two patients, repeating a T1-weighted FLASH sequence (TR 100 ms, TE 5 ms, flip angle 90 degrees) every 20 s. Follow-up MRI examinations 2-3 weeks, 6-8 weeks, and 6-12 months after LITT were carried out in eight patients, using T2-weighted FSE images and contrast-enhanced T1-weighted SE images. RESULTS: The prostate was well delineated in all patients on T2-weighted FSE images, with a rather homogeneous peripheral gland and an inhomogeneous central gland. Volume measurements yielded reproducibilities of 3.2%-4.7%. Signal intensity in the FLASH sequence decreased during LITT, both in the prostate in vivo and in specimens of bovine prostate and seminal vesicles in vitro, with signal developments running in parallel. Areas of energy deposition and signal alteration were not sharply delineated. The latter margin of the laser-induced lesions could not be predicted from the FLASH images, while the tip of the laser fibre was easily recognized. Contrast-enhanced T1-weighted MR images immediately after LITT clearly demarcated low signal intensity laser lesions from high signal intensity surrounding prostate tissue. Follow-up examinations showed a decrease of 20% of prostate volume over a period of 6-12 months after LITT. Correlation between prostate volume development and lesion volume alteration was 0.85-0.90 (P = 0.002-0.007) at all follow-up times. CONCLUSIONS: MRI allows rather precise recognition of intraprostatic alterations after LITT, including volume changes over a period of up to 1 year after therapy that can be predicted immediately after LITT. While laser energy deposition in the prostate can be monitored by MRI with T1-weighted FLASH sequences as a function of temperature alteration, it is not possible to determine the lesion margins immediately from the FLASH images. Online temperature development map generation will be necessary to influence on-going LITT procedures with MRI.