2-deoxy-2-[18]fluoro-D-glucose PET/CT (18FDG PET/CT) may not be a viable biomarker in Pompe disease.

BACKGROUND: Pompe disease (PD) is an autosomal recessive, lysosomal storage disease due to a mutation of the acid α-glucosidase (GAA) gene. In adult patients, PD is characterized by slowly progressive limb-girdle and trunk myopathy and restrictive respiratory insufficiency. Enzyme replacement therapy (ERT) is available, improving or stabilizing muscle-function in some and slowing deterioration in other patients. Unfortunately, there is no biomarker available to indicate therapeutic efficacy and/or disease activity. Whole body MRI depicts all skeletal muscles demonstrating foci of atrophic muscles, i.e., late and irreversible pathological changes. Any method indicating the localizations of increased muscle glycogen storage, muscle inflammation and/or degradation could possibly help identifying newly afflicted tissue and may be of prognostic value. We therefore investigated 2-deoxy-2-[18]fluoro-D-glucose (FDG) PET, a biomarker for glucose-metabolism, as a tool to evaluate disease activity and prognosis in PD. METHODS: In a pilot study, we investigated four patients by FDG dynamic PET/CT while on ERT. One patient had FDG-PET/CT twice, before and after 12 months on ERT. Dynamic FDG-PET/CT quantifies the metabolic rate of glucose utilisation in mg/ml/min. MRI was performed in parallel with pelvic and thigh muscles semi-quantitatively scored for atrophy and disease-activity. RESULTS: None of the muscles analysed showed a focally increased FDG-uptake. Thus, quantification of muscle glucose metabolism could not be calculated. However, increased FDG-uptake, i.e., increased glucose utilisation, was observed in the respiratory muscles of one patient with severe, restrictive respiratory failure. In contrast, specific MRI sequences showed oedematous as well as atrophic muscle areas in PD. CONCLUSIONS: Our pilot study demonstrates that FDG-uptake does not correlate with glycogen storage in vivo. In contrast, MRI is an excellent tool to demonstrate the extent of muscle involvement. Specific MRI sequences may even demonstrate early changes possibly allowing prognostic predictions or localization of early stages of PD.

Lung Volume Reduction in Pulmonary Emphysema from the Radiologist's Perspective.

UNLABELLED: Pulmonary emphysema causes decrease in lung function due to irreversible dilatation of intrapulmonary air spaces, which is linked to high morbidity and mortality. Lung volume reduction (LVR) is an invasive therapeutical option for pulmonary emphysema in order to improve ventilation mechanics. LVR can be carried out by lung resection surgery or different minimally invasive endoscopical procedures. All LVR-options require mandatory preinterventional evaluation to detect hyperinflated dysfunctional lung areas as target structures for treatment. Quantitative computed tomography can determine the volume percentage of emphysematous lung and its topographical distribution based on the lung's radiodensity. Modern techniques allow for lobebased quantification that facilitates treatment planning. Clinical tests still play the most important role in post-interventional therapy monitoring, but CT is crucial in the detection of postoperative complications and foreshadows the method's high potential in sophisticated experimental studies. Within the last ten years, LVR with endobronchial valves has become an extensively researched minimally-invasive treatment option. However, this therapy is considerably complicated by the frequent occurrence of functional interlobar shunts. The presence of "collateral ventilation" has to be ruled out prior to valve implantations, as the presence of these extraanatomical connections between different lobes may jeopardize the success of therapy. Recent experimental studies evaluated the automatic detection of incomplete lobar fissures from CT scans, because they are considered to be a predictor for the existence of shunts. To date, these methods are yet to show acceptable results. KEY POINTS: Today, surgical and various minimal invasive methods of lung volume reduction are in use. Radiological and nuclear medical examinations are helpful in the evaluation of an appropriate lung area. Imaging can detect periinterventional complications. Reduction of lung volume has not yet been conclusively proven to be effective and is a therapeutical option with little scientific evidence.

Ventilation/perfusion SPECT/CT in patients with pulmonary emphysema. Evaluation of software-based analysing.

UNLABELLED: The purpose of this study was to evaluate the reproducibility of a new software based analysing system for ventilation/perfusion single-photon emission computed tomography/computed tomography (V/P SPECT/CT) in patients with pulmonary emphysema and to compare it to the visual interpretation. PATIENTS, MATERIAL AND METHODS: 19 patients (mean age: 68.1 years) with pulmonary emphysema who underwent V/P SPECT/CT were included. Data were analysed by two independent observers in visual interpretation (VI) and by software based analysis system (SBAS). SBAS PMOD version 3.4 (Technologies Ltd, Zurich, Switzerland) was used to assess counts and volume per lung lobe/per lung and to calculate the count density per lung, lobe ratio of counts and ratio of count density. VI was performed using a visual scale to assess the mean counts per lung lobe. Interobserver variability and association for SBAS and VI were analysed using Spearman's rho correlation coefficient. RESULTS: Interobserver agreement correlated highly in perfusion (rho: 0.982, 0.957, 0.90, 0.979) and ventilation (rho: 0.972, 0.924, 0.941, 0.936) for count/count density per lobe and ratio of counts/count density in SBAS. Interobserver agreement correlated clearly for perfusion (rho: 0.655) and weakly for ventilation (rho: 0.458) in VI. CONCLUSIONS: SBAS provides more reproducible measures than VI for the relative tracer uptake in V/P SPECT/CTs in patients with pulmonary emphysema. However, SBAS has to be improved for routine clinical use.

Pulmonary lymphangioleiomyomatosis: analysis of disease manifestation by region-based quantification of lung parenchyma.

PURPOSE: Lymphangioleiomyomatosis (LAM) is characterized by proliferation of smooth muscle tissue that causes bronchial obstruction and secondary cystic destruction of lung parenchyma. The aim of this study was to evaluate the typical distribution of cystic defects in LAM with quantitative volumetric chest computed tomography (CT). MATERIALS AND METHODS: CT examinations of 20 patients with confirmed LAM were evaluated with region-based quantification of lung parenchyma. Additionally, 10 consecutive patients were identified who had recently undergone CT imaging of the lung at our institution, in which no pathologies of the lung were found, to serve as a control group. Each lung was divided into three regions (upper, middle and lower thirds) with identical number of slices. In addition, we defined a "peel" and "core" of the lung comprising the 2 cm subpleural space and the remaining inner lung area. Computerized detection of lung volume and relative emphysema was performed with the PULMO 3D software (v3.42, Fraunhofer MEVIS, Bremen, Germany). This software package enables the quantification of emphysematous lung parenchyma by calculating the pixel index, which is defined as the ratio of lung voxels with a density <-950HU to the total number of voxels in the lung. RESULTS: Cystic changes accounted for 0.1-39.1% of the total lung volume in patients with LAM. Disease manifestation in the central lung was significantly higher than in peripheral areas (peel median: 15.1%, core median: 20.5%; p=0.001). Lower thirds of lung parenchyma showed significantly less cystic changes than upper and middle lung areas combined (lower third: median 13.4, upper and middle thirds: median 19.0, p=0.001). CONCLUSION: The distribution of cystic lesions in LAM is significantly more pronounced in the central lung compared to peripheral areas. There is a significant predominance of cystic changes in apical and intermediate lung zones compared to the lung bases.

Impact of magnification views on the characterization of microcalcifications in digital mammography.

PURPOSE: To evaluate the additional benefit of true geometric (air-gap) magnification views for the characterization of microcalcifications in digital mammography. MATERIALS AND METHODS: After ethical approval, we retrospectively reviewed patient records to identify 100 patients with suspicious microcalcifications (35 malignant, 65 benign) who had a standard digital mammography and an additional digital magnification view in the same projection within three months. All images were obtained using an amorphous silicon-based full-field digital system (Senographe 2000 D, GE Healthcare, Chalfont St. Giles, UK). Images were independently analyzed by six board-certified radiologists. The probability of malignancy was estimated using first standard contact mammography alone (MG) and then mammography in combination with the magnification view (MG+MAG) using a modified Breast Imaging Reporting and Data System (BI-RADS) classification system and a percentage scale. Results were compared using receiver operating characteristic (ROC) analysis. In addition, readers assessed the subjective visibility of the calcifications. RESULTS: For all six readers combined, the area under the curve (AUC) was 0.664 ±â€Š0.052 for MG and 0.813 ±â€Š0.042 for MG + MAG, resulting in a statistically significant improvement of 0.148 ±â€Š0.120. Each reader had a higher AUC for MG + MAG than MG, with the improvement being statistically significant in four of the six readers. In 76.34 % of the cases, MG + MAG resulted in better visibility of calcifications compared with mammography alone. In 33 % slightly more and in 39 % significantly more calcifications were found. CONCLUSION: Even in digital mammography with the option of using electronic magnification (zoom) at the viewing workstation, true geometric (air-gap) magnification views remain important for the visibility and correct classification of microcalcifications and for the assessment of their extent.

Optical imaging of breast cancer using hemodynamic changes induced by valsalva maneuver.

PURPOSE: To investigate whether changes in hemodynamics induced by Valsalva maneuver can be exploited for detecting and characterizing breast lesions by optical mammography. MATERIALS AND METHODS: 30 women underwent optical imaging of the breast using a DYNOT 232 system and performing Valsalva maneuvers prior to biopsy. Changes in light absorption due to changes in oxyhemoglobin and deoxyhemoglobin concentrations were recorded volumetrically and in a time-resolved manner. The parameters full width at half maximum (FWHM), time to ten (TTT), and peak amplitude (PA) of the reconstructed concentration time curves yielded color-coded maps of the breast which were separately evaluated by two experienced readers for detection rate, degree of visibility, and detection of additional lesions. ROC analysis was performed with the evaluation results. RESULTS: 10 patients were excluded from analysis due to artifacts or inadequately performed Valsalva maneuver. The resulting 20 patients showed a clear increase in oxygenated and deoxygenated hemoglobin concentration after the onset of the Valsalva maneuver. ROC analysis yielded AUC values (0.393 - 0.779) that did not differ from random probabilities. The highest AUC values were obtained for FWHM (AUC: 0.779, detection rates [60 - 70 %], identification of additional lesions [55 - 70 %]). PA analysis had the highest detection rate (70 - 90 %) but also the highest identification of false-positive additional lesions (80 - 90 %). The concordance rates of the two readers for malignant lesions were satisfactory (0.524 - 1.0). CONCLUSION: Our study revealed susceptibility to artifacts and a large number of false-positive additional lesions, suggesting that the evaluation of hemodynamic changes after Valsalva maneuver by optical imaging is not a promising method.

Intraoperative specimen radiography in patients with nonpalpable malignant breast lesions.

PURPOSE: Specimen mammography of nonpalpable wire-localized breast lesions is the standard in breast-conserving surgery. The aim of this study was to evaluate the reliability of intraoperative 2-view specimen mammography in different cancer types. MATERIALS AND METHODS: After ethics approval, 3 readers retrospectively evaluated margins on 266 2-view specimen radiographs. They determined the closest margin and the orientation. The results were correlated with the histopathology (intra-class correlation coefficient [ICC] and contingency coefficient [CC]) and compared (Wilcoxon test). RESULTS: Invasive ductal carcinoma (IDC) with ductal carcinoma in situ (DCIS) was present in 115 (43 %), IDC in 75 (28 %), invasive lobular carcinoma (ILC) in 57 (22 %) and rare cancers (CA) in 19 specimens (7 %). The sensitivity/specificity and positive/negative predictive value (P/NPV) of specimen mammography were 0.50/0.86 and 0.86/0.50 for CA, 0.42/0.68 and 0.48/0.63 for IDC, 0.36/0.81 and 0.69/0.51 for ILC, and 0.22/0.78 and 0.68/0.32 for IDC+DCIS. Readers correctly identified the orientation of the closest margin in at least one view in an average of 149 specimens (56 %). CCs were between 0.680 (IDC) and 0.912 (CA), suggesting a moderate correlation between radiographic and histological orientation. The correlations were worse for the radiographic and histological distances, with ICC ranging from 0.238 (ILC) to 0.475 (CA). The Wilcoxon test revealed overestimation of the radiographic margins compared to the histological ones for DCIS. CONCLUSION: Our results suggest that specimen radiography has relatively good overall specificity and good PPV, while the sensitivity and NPV are low for DCIS. A negative result on specimen radiography does not rule out histologically involved margins.

[Percutaneous CT-guided high-dose brachytherapy (CT-HDRBT) ablation of primary and metastatic lung tumors in nonsurgical candidates]. / Perkutane CT-gesteuerte Hochdosis-Brachytherapie (CT-HDRBT) von primären und metastatischen Lungentumoren in nicht chirurgischen Kandidaten.

PURPOSE: To evaluate the safety and efficacy of CT-guided high-dose brachytherapy (CT-HDRBT) ablation of primary and metastatic lung tumors. MATERIALS AND METHODS: Between November 2007 and May 2010, all consecutive patients with primary or metastatic lung tumors, unsuitable for surgery, were treated with CT-HDRBT. Imaging follow-up after treatment was performed with contrast-enhanced CT at 6 weeks, 3 months and every 6 months after the procedure. The endpoints of the study were local tumor control and time to progression. The Kaplan-Meier method was used to estimate survival functions and local tumor progression rates. RESULTS: 34 procedures were carried out on 33 lesions in 22 patients. The mean diameter of the tumors was 33.3 mm (SD = 20.4). The first contrast-enhanced CT showed that complete ablation was achieved in all lesions. The mean minimal tumor enclosing dose was 18.9 Gy (SD = 2). Three patients developed a pneumothorax after the procedure. The mean follow-up time was 13.7 (3 - 29) months. 2 of 32 lesions (6.25 %) developed a local tumor progression. 8 patients (36.3 %) developed a distant tumor progression. After 17.7 months, 13 patients were alive and 9 patients had died. CONCLUSION: CT-HDRBT ablation is a safe and attractive treatment option for patients with lung malignancies and allows targeted destruction of tumor tissue with simultaneous preservation of important lung structures. Furthermore, CT-HDRBT is independent of the size of the lesion and its location within the lung parenchyma.

Diagnostic performance of a Near-Infrared Breast Imaging system as adjunct to mammography versus X-ray mammography alone.

OBJECTIVES: Radiologist reader performance for breast cancer detection using mammography plus Near-Infrared Breast Imaging (NIBI) was compared with mammography alone. METHODS: Two hundred seventy-six consecutive patients with suspected breast lesions underwent both mammography and NIBI. Four blinded radiologists independently first reviewed the mammograms alone. Readers subsequently reviewed the mammograms in combination with NIBI. The diagnostic benefit of NIBI as an adjunct to mammography was determined by performing receiver operating characteristics (ROC) analyses for each reader based on BI-RADS categories (Breast Imaging Reporting and Data System) and LOS (level of suspicion) scores. Additionally, a multireader-multicase (ROC) analysis of variance (ANOVA) was carried out. RESULTS: For the LOS-based analysis, the combination of mammography and NIBI resulted in a slightly larger area under the curve (AUC) for all four readers. The analysis based on BI-RADS categories also demonstrated a slight increase in AUC for three readers for the combination of mammography and NIBI compared with mammography alone. For the fourth reader, AUC was smaller for the combination compared with mammography alone. Neither for the separate ROC-analyses nor for the ANOVA, significant differences between the two methods were obtained. CONCLUSIONS: The combination of mammography and NIBI did not perform significantly better than mammography alone. KEY POINTS: The intrinsic contrast provided by optical breast imaging may be inadequate We found slightly (but nonsignificant) higher accuracy for optical imaging and mammography compared with mammography alone. Contrast agents might be necessary to improve the performance of optical breast imaging.

Fast 3D Near-infrared breast imaging using indocyanine green for detection and characterization of breast lesions.

PURPOSE: To evaluate fast 3D near-infrared breast imaging using the optical contrast agent indocyanine green (ICG) for the detection and characterization of breast lesions. MATERIALS AND METHODS: 30 patients with suspicious breast lesions on mammography and/or ultrasound underwent fast 2 Hz 3D optical mammography before, during, and after administration of a 25 mg ICG bolus prior to needle biopsy. The bolus kinetics is analyzed using two perfusion parameters and a derived parameter: "peak amplitude" (PA), "time-to-peak" (TTP) and "peak-time grouped amplitude" (PTA). A receiver operating characteristic curve (ROC) analysis was performed to define a PTA cut-off for reader-independent differentiation of benign and malignant lesions. 8 patients had to be excluded from data analysis. Overall 14 breasts bearing a malignant lesion, 8 breasts bearing a benign lesion and 3 healthy breasts were analyzed. RESULTS: The cut-off-based PTA analysis allowed correct detection for 12 of 14 malignant lesions (tumor size: 8 - 80 mm; sensitivity = 85.7 %). Two malignant lesions were missed. In the benign study group only one fibroadenoma was detected (specificity = 87.5 %). The PTA values differed significantly between the benign group and the malignant group (Mann-Whitney U-test, p < 0.05). Breasts with malignant lesions showed higher peaks at early time-points in ICG perfusion. CONCLUSION: Early perfusion analysis of ICG-enhanced 3D fast optical mammography revealed different enhancement patterns for benign and malignant lesions. This approach might help with the detection of malignant breast lesions and the differentiation from benign lesions.

Ischemic-type biliary lesions after ortothopic liver transplantation: diagnosis with magnetic resonance cholangiography.

PURPOSE: To determine the accuracy of magnetic resonance (MR) cholangiography for detection of ischemic-type biliary lesions (ITBL) following orthotropic liver transplantation (OLT). MATERIALS AND METHODS: MR cholangiography was performed in 16 patients with established diagnosis of ITBL following OLT. Two blinded observers reviewed all images in consensus and recorded diagnostic features including presence of intrahepatic and extrahepatic biliary strictures, dilatations, beading, pruning, and filling defects. Sensitivity, specificity, positive predictive value, and accuracy of MR cholangiography were calculated. Final diagnosis was established at endoscopic retrograde cholangiography. RESULTS: MR cholangiography proved to be a valuable tool for the detection of stenoses and dilatations in patients with ITBL following OLT. Sensitivity of the different diagnostic features ranged between 71% and 100%, specificity between 50% and 100%, accuracy between 81% and 100%, and positive predictive value between 87% and 100%. CONCLUSION: MR cholangiography proved to be an accurate imaging technique to noninvasively detect biliary complications in patients with ITBL after OLT.

Identification of the primary tumour with the help of diffusion-weighted MRI in a patient with autosomal dominant polycystic kidney disease and metastatic renal cell carcinoma.

We report the case of a 47-year-old patient with autosomal dominant polycystic kidney disease, who became symptomatic owing to a painful metastasis of a renal cell carcinoma. Abdominal sonography, multiphase CT and MRI were performed in order to localise and resect the primary tumour, but its identification was severely hampered owing to multiple renal cysts. In addition to standard MRI protocol, a spin-echo, single-shot echo planar diffusion-weighted imaging sequence was performed. The mean apparent diffusion coefficient (ADC) of renal cysts was 2.66±0.12 × 10(-3) mm(2) s(-1), 1.76±0.19 × 10(-3) mm(2) s(-1) of renal parenchyma in and 1.26±0.18 × 10(-3) mm(2) s(-1) of a suspicious soft-tissue mass at the midsection of the right kidney, indicating an area of higher cellularity. This value was significant lower than the ADC obtained for renal parenchyma (p<0.0001). Right-sided nephrectomy was performed and the pathological diagnosis of the suspicious lesion was clear cell renal carcinoma.

Qualitative JPEG 2000 compression in digital mammography - evaluation using 480 mammograms of the CDMAM phantom.

PURPOSE: The DICOM standard supports both quantitative and qualitative lossy compression of mammograms.The purpose of this study was to investigate qualitative JPEG 2000 lossy compression and how different factors such as object thickness, radiation dose, and lossy compression levels affect image quality. MATERIALS AND METHODS: The CDMAM phantom Artinis 3.4 was radiographed with 4 different object thicknesses and 5 different doses. The images were compressed at 10 different compression levels. The image quality was assessed by the software interpolated IQFinv value. RESULTS: Lossy 90 resulted in 89 % data reduction, lossy 70 in 95 % data reduction and lossy 60 in 96 % data reduction. At higher compression levels (lossy 30), the resulting image quality ranged from 80 - 36 %, and at low compression levels (lossy 90), it ranged from 89 - 93 %. The object thickness was found to significantly interact with the compression level with regard to the resulting image quality: a higher object thickness resulted in increasingly poor image quality at increasing compression levels (p < 0.05). CONCLUSION: Higher qualitative JPEG 2000 compression levels contribute only little additional data reduction, while the resulting image quality cannot be reliably predicted. Factors affecting image quality such as radiation dose and object thickness should be taken into account when performing image compression. Large object thicknesses should be compressed with caution because the loss of image quality is greater when intelligent data compression algorithms are used.

[Magnetic resonance cholangiographic (MRCP) features of ischemic-type biliary lesions (ITBL): a case-control study]. / Magnetresonanz-Cholangiografie (MRCP) bei Patienten mit Ischemic-Type Biliary Lesions (ITBL): eine Fall-Kontroll-Studie.

PURPOSE: To evaluate the spectrum of MR cholangiography (MRCP) features of ischemic-type biliary lesions (ITBL) after orthotopic liver transplantation (OLT). MATERIALS AND METHODS: 30 patients (16 m, 14 f) with an average age of 52 years (9 - 69 y) were examined in two 1.5 MR units using breath-hold 2D-SS-FSE-sequences and 3D-MRCP sequences. 20 of the 30 patients had an established ITBL, and the remaining 10 patients were post-OLT controls. MRCPs were evaluated independently by two experienced radiologists that were blinded to the clinical history as well as the results of other imaging modalities. All images were analyzed for the presence of 16 different pathological features. Differences between ITBL patients and controls were analyzed using the Mann-Whitney-U Test. Inter-rater variability was tested using the Cohen's Kappa test. RESULTS: Abnormal findings of bile ducts were seen in all patients. The most common findings were (in percentage for reader 1 / 2) intrahepatic bile duct dilatation (95 % / 95 %) and extrahepatic bile duct stenoses (95 % / 85 %), followed by intrahepatic main duct stenoses (90 % / 95 %) and segmental duct stenoses (85 % / 85 %). Differences between ITBL patients and controls were significant for most of the analyzed features (Mann-Whitney-U test, p < 0.05). For 12 of 16 features, there was substantial or almost perfect agreement (κ = 0.61 - 1.00), for 2 of 16 features moderate agreement (κ = 0.41- 0.60) and for 2 of 16 features fair agreement (κ < 0.40). CONCLUSION: In patients with ITBL, MR cholangiography reveals characteristic features that may allow differentiation from other biliary complications after liver transplantation.

Ovarian artery embolization in patients with collateral supply to symptomatic uterine leiomyomata.

PURPOSE: To evaluate the safety and outcome of ovarian artery embolization (OAE) in patients with collateral supply to symptomatic uterine leiomyomata. MATERIALS AND METHODS: Thirteen patients with relevant leiomyoma perfusion by way of enlarged ovarian arteries underwent additional OAE during the same (N = 10) or a second procedure (N = 3). Uterine artery embolization (UAE) was performed bilaterally in 10 and unilaterally in 2 patients with a single artery. One patient had no typical uterine arteries but bilaterally enlarged ovarian arteries, prompting bilateral OAE. OAE was accomplished with coil embolization in one and particle embolization in 12 patients. Symptoms before therapy and clinical outcome were assessed using a standardized questionnaire. Contrast-enhanced magnetic resonance (MR) imaging after embolization was available in 11 of 13 patients and was used to determine the percentage of fibroid infarction. RESULTS: UAE and OAE were technically successful in all patients. One patient experienced prolonged irritation at the puncture site. Median clinical follow-up time was 16 months (range 4-37). Ten of 13 patients showed improvement or complete resolution of clinical symptoms. One patient reported only slight improvement of her symptoms. These women presented with regular menses. Two patients (15%), 47 and 48 years, both with unilateral OAE, reported permanent amenorrhea directly after embolization. Their symptoms completely resolved. Seven patients showed complete and 4 showed >90% fibroid infarction after embolization therapy. CONCLUSION: OAE is technically safe and effective in patients with ovarian artery collateral supply to symptomatic uterine leiomyomata. The risk of permanent amenorrhea observed in this study is similar to the reported incidence after UAE.

[Targeted methods for measuring patient satisfaction in a radiological center]. / Gezielte Methoden zur Messung der Patientenzufriedenheit in einem radiologischen Versorgungszentrum (MVZ).

PURPOSE: To investigate two event-oriented methods for evaluating patient satisfaction with radiological services like outpatient computed tomography (CT) examinations. MATERIALS AND METHODS: 159 patients (55% men, 45% women) were asked to complete a questionnaire to provide information about their satisfaction with their examination. At first, patients were asked to spontaneously recall notably positive and negative aspects (so-called "critical incidents", critical incident technique = CIT) of the examination. Subsequently a flow chart containing all single steps of the examination procedure was shown to all patients. They were asked to point out the positive and negative aspects they perceived at each step (so-called sequential incident technique = SIT). RESULTS: The CIT-based part of the questionnaire yielded 356 comments (183 positive and 173 negative), which were assigned to one of four categories: interaction of staff with patient, procedure and organization, CT examination, and overall setting of the examination. Significantly more detailed comments regarding individual aspects of the CT examination were elicited in the second part of the survey, which was based on the SIT. There were 1413 statements with a significantly higher number of positive comments (n = 939, 66%) versus negative comments (n = 474, 34%; p < 0.001). CONCLUSION: The critical and sequential incident techniques are suitable to measure the subjective satisfaction with the delivery of radiological services such as CT examinations. Positive comments confirm the adequacy of the existing procedures, while negative comments provide direct information about how service quality can be improved.

Brain activation responses to subliminal or supraliminal rectal stimuli and to auditory stimuli in irritable bowel syndrome.

Visceral hypersensitivity in irritable bowel syndrome (IBS) has been associated with altered cerebral activations in response to visceral stimuli. It is unclear whether these processing alterations are specific for visceral sensation. In this study we aimed to determine by functional magnetic resonance imaging (fMRI) whether cerebral processing of supraliminal and subliminal rectal stimuli and of auditory stimuli is altered in IBS. In eight IBS patients and eight healthy controls, fMRI activations were recorded during auditory and rectal stimulation. Intensities of rectal balloon distension were adapted to the individual threshold of first perception (IPT): subliminal (IPT -10 mmHg), liminal (IPT), or supraliminal (IPT +10 mmHg). IBS patients relative to controls responded with lower activations of the prefrontal cortex (PFC) and anterior cingulate cortex (ACC) to both subliminal and supraliminal stimulation and with higher activation of the hippocampus (HC) to supraliminal stimulation. In IBS patients, not in controls, ACC and HC were also activated by auditory stimulation. In IBS patients, decreased ACC and PFC activation with subliminal and supraliminal rectal stimuli and increased HC activation with supraliminal stimuli suggest disturbances of the associative and emotional processing of visceral sensation. Hyperreactivity to auditory stimuli suggests that altered sensory processing in IBS may not be restricted to visceral sensation.

Activation and habituation in olfaction--an fMRI study.

This study investigated human BOLD responses in primary and higher order olfactory cortices following presentation of short- and long-duration odorant stimuli using a 3-T MR scanner. The goal was to identify temporal differences in the course of the response that might underlie habituation. A short-duration stimulus (9 s) consistently activated the primary olfactory cortex (POC). After a long stimulus (60 s), the temporal form of the response differed in different parts of the olfactory network: (1) The POC (piriform, entorhinal cortex, amygdala) and, interestingly, the hippocampus and, to a certain degree, the anterior insula show a short, phasic increase in the signal, followed by a prolonged decrease below baseline. (2) In the orbitofrontal cortex a sustained increase in activation was seen. This increase lasted approximately as long as the duration of odorant presentation ( approximately 60 s). (3) The mediodorsal nucleus of the thalamus and the caudate nucleus responded with an increase in signal which returned to baseline after approximately 15 to 30 s. The correlated biphasic hemodynamic response in the POC, hippocampus, and anterior insula during prolonged olfactory stimulation suggests that these three areas may interact closely with each other in the control of habituation. These results extend recent data which showed habituation of the rat piriform cortex and dissociation between the POC and the orbitofrontal cortex.