Diffusion-weighted imaging of the head and neck in healthy subjects: reproducibility of ADC values in different MRI systems and repeat sessions.

BACKGROUND AND PURPOSE: DWI is typically performed with EPI sequences in single-center studies. The purpose of this study was to determine the reproducibility of ADC values in the head and neck region in healthy subjects. In addition, the reproducibility of ADC values in different tissues was assessed to identify the most suitable reference tissue. MATERIALS AND METHODS: We prospectively studied 7 healthy subjects, with EPI and TSE sequences, on 5 MR imaging systems at 3 time points in 2 institutions. ADC maps of EPI (with 2 b-values and 6 b-values) and TSE sequences were compared. Mean ADC values for different tissues (submandibular gland, sternocleidomastoid muscle, spinal cord, subdigastric lymph node, and tonsil) were used to evaluate intra- and intersubject, intersystem, and intersequence variability by using a linear mixed model. RESULTS: On 97% of images, a region of interest could be placed on the spinal cord, compared with 87% in the tonsil. ADC values derived from EPI-DWI with 2 b-values and calculated EPI-DWI with 2 b-values extracted from EPI-DWI with 6 b-values did not differ significantly. The standard error of ADC measurement was the smallest for the tonsil and spinal cord (standard error of measurement = 151.2 × 10(-6) mm/s(2) and 190.1 × 10(-6) mm/s(2), respectively). The intersystem difference for mean ADC values and the influence of the MR imaging system on ADC values among the subjects were statistically significant (P < .001). The mean difference among examinations was negligible (ie, <10 × 10(-6) mm/s(2)). CONCLUSIONS: In this study, the spinal cord was the most appropriate reference tissue and EPI-DWI with 6 b-values was the most reproducible sequence. ADC values were more precise if subjects were measured on the same MR imaging system and with the same sequence. ADC values differed significantly between MR imaging systems and sequences.

Diffusion-weighted MR imaging in head and neck cancer: comparison between half-fourier acquired single-shot turbo spin-echo and EPI techniques.

BACKGROUND AND PURPOSE: Several studies have reported on the clinical utility of DWI in head and neck cancer, but none of these studies compared HASTE with EPI-DWI in patients with head and neck cancer. The aim of our study was to compare detection and delineation of primary tumors and lymph nodes by using HASTE and EPI-DWI techniques in patients with HNSCC. MATERIALS AND METHODS: Twelve patients with HNSCC and a total of 12 primary tumors and 77 visualized lymph nodes on MR imaging underwent DWI by using both EPI-based and HASTE techniques. Interobserver agreement for detection, delineation, and ADC values of primary tumors and lymph nodes was assessed by 2 radiologists, and artifacts for both DWI techniques were described. RESULTS: The number of lesions (primary tumors and lymph nodes) identified on pretreatment EPI-DWI was higher compared with pretreatment HASTE-DWI, with means of total lesions of 88.5 and 69.0, respectively. Delineation of lesions was also better on pretreatment EPI-DWI compared with pretreatment HASTE-DWI, with means of well-delineated lesions of 80.5 and 27.5, respectively. Both EPI- and HASTE-DWI showed good interobserver agreement between radiologists of ADC values in lesions with ICC values of 0.79 and 0.92, respectively. Intraobserver agreement for ADC values in lesions assessed with EPI- versus HASTE-DWI techniques was low, with ICC values of 0.31 and 0.42, respectively. Significant interobserver disagreement concerning detection was only seen with HASTE-DWI, and none of the DWI techniques showed significant interobserver disagreements regarding delineation. EPI-DWI was more prone to susceptibility artifacts than HASTE-DWI: Ninety-one percent of primary tumors and 16% of lymph nodes were affected by susceptibility artifacts on pretreatment EPI-DWI, whereas these artifacts were not seen on HASTE-DWI. CONCLUSIONS: Primary tumors and lymph nodes are more easily visualized on EPI-DWI compared with HASTE-DWI. EPI-DWI has geometric distortion, however, which has a negative effect on interobserver agreement of ADC values.

Has the degree of contrast enhancement with MR imaging in laryngeal carcinoma added value to anatomic parameters regarding prediction of response to radiation therapy?

BACKGROUND AND PURPOSE: Our aim was to retrospectively investigate the prognostic significance of the degree of contrast enhancement in tumors and its additional value in previously considered MR imaging parameters with regard to local control of laryngeal cancer treated with radiation therapy (RT) alone. MATERIALS AND METHODS: Pretreatment MR images of 64 consecutive patients (54 men and 10 women, 43-80 years of age) with supraglottic and glottic cancer were retrospectively reviewed on clinical and previously considered MR imaging parameters such as tumor involvement of specific laryngeal anatomic subsites, including laryngeal cartilages, tumor volume, extralaryngeal tumor spread, and, in addition, the degree of contrast enhancement. Clinical and MR imaging parameters were associated with regard to local control at 2 years by using the Cox regression model. "Local control" was defined as absence of primary tumor recurrence. RESULTS: When using a threshold of the mean average contrast enhancement of 77%, the 2-year local control rate in the groups of patients with a degree of enhancement below and above this threshold was 57% and 70%, respectively (P=.3). Enhancement of tumor tissue in pre-epiglottic space (PES) was low, most probably due to its adipose tissue and poor vascular content, whereas tumor tissue involving paraglottic space (PGS) did enhance. Results of multivariate analysis indicated that the degree of contrast enhancement yielded the prognostic information (P=.07) with 2 independent prognostic factors: primary tumor volume (P=.007) and subglottic extension (P=.002) with regard to local control. Using these previously mentioned 3 MR imaging parameters as potential risk factors, we defined 4 categories, resulting in the following local control rates respectively: 90% for the group without risk factors, 73% for the group with 1, 60% for the group with 2, and finally 0% for the group with 3 risk factors, which was significantly lower than the rates in previous risk groups (P < .001). CONCLUSION: PES has a lower degree of contrast enhancement than the PGS and may correlate with the worse outcome. Including a low degree of contrast enhancement as a parameter to primary tumor volume and subglottic extension may increase the predictive value of MR imaging for local outcome and may be helpful to identify a subset of patients whose tumors all recurred locally within 2 years after primary RT.

[Implication of the self-help mechanism in the geriatric club (author's transl)]. / Einbeziehung des Selbstschutzes in die Aufgaben des geriatrischen Klubs.

In the paper clinical investigations are given of the implication of the self-help mechanism with the 125 members of the Geriatric club of the Clinical hospital "Dr. Mladen Stojanovic" in Zagreb during the year 1979. The results show that in this phase of the development of contemporary society and medicine and prevention geriatrics self-help is the only way of care and responsibility for the health of a great number of the population. Self-help is built-in everyday life and activity of the members of the club. Elder persons take part in the permanent care of their own health through the group mechanism of self-help by helping and caring for themselves on te basis of obtained health informations, knowledge and experience with society and public health services. In time they discover factors of risk which in many cases provoke a number of chronic illness and thereby put health in danger. The perspectives of self-help are in the scientific work of various social structures and in finding out specific methods of individual and group self-help for attacking mass chronic sicknesses of contemporary civilisation.

[The role of sociotherapeutic community in geriatry (author's transl)]. / Die Rolle der soziotherapeutischen Gemeinschaft in der Geriatrie.

Based on the experience with 120 members of a geriatric club we consider life in the sociotherapeutic community, respectively the geriatric club, is a basic condition for adjusted socialisation of the elderly. Through different activities in the club the elderly restores his social consciousness he lost when retiring. Mutual approach, intellectual exchange, arrangements of excursions, performances and concerts are realized in the club. The basic concept of sociotherapeutic community is the elderly's understanding of his own problems.