Value of high-field magnetic resonance imaging for diagnosis and classification of acute colonic diverticulitis.

OBJECTIVES: Due to limited and outdated literature, the role of magnetic resonance imaging (MRI) in the diagnostic work-up of acute colonic diverticulitis (ACD) is still under debate. The purpose of this study was to compare the performance of modern high-field MRI and multidetector computed tomography (MDCT) in the diagnosis and classification of ACD. METHODS: In our prospective study 24 emergency patients with the clinical diagnosis of ACD received MDCT and high-field MRI. Imaging features of ACD were assessed and categorized according to the classification of diverticular disease (CDD) by three independent readers. Results were matched with the final clinical report. RESULTS: MRI with a specialized examination protocol clearly depicted all relevant findings of ACD. Statistical analysis resulted in an almost perfect strength of agreement between CT and MRI across all readers for the final CDD category (κ = 0.94) and the stage-related image features (κ = 0.98). Moderate agreement was seen for the detection of micro-abscesses (κ = 0.78), with a slight advantage for MRI. CONCLUSION: Modern high-field MRI is fully comparable to MDCT in the assessment of ACD and has the potential to serve as a first-line imaging tool.

[Rectal cancer update: postneoadjuvant staging]. / Update Rektumkarzinom: postneoadjuvantes Staging.

Over the last two decades, magnetic resonance imaging (MRI) has continuously been gaining influence in modern management of rectal cancer. Bringing morphological and functional features together improves the differentiation of responders from nonresponders, provides for accurate surgical planning, intensified radiation therapy regimes, and watch-and-wait strategies. A shift from TNM staging towards risk stratification of rectal cancer patients, patient selection to increasingly individualized therapies, and intensified surveillance has contributed to the transformation of rectal MRI into a true gamechanger.

[Diverticular disease: stage-related diagnostic imaging]. / Divertikelkrankheit: stadiengerechte bildgebende Diagnostik.

BACKGROUND: Diverticular disease frequently leads to emergency admissions. Clinical parameters are not sufficiently accurate to determine the extent of acute colonic diverticulitis, thus a quick, reproducible and valid diagnostic imaging procedure is required. OBJECTIVE: In the following, the imaging methods commonly used for the diagnostic work-up and staging of diverticulitis are presented and classified in the context of the data situation and clinical reality. RESULTS: Multidetector computed tomography (MDCT) is the current diagnostic gold standard for the imaging evaluation of diverticulitis and the basis for guideline-conform treatment decisions according to the classification of diverticular disease (CDD). DISCUSSION: The role of magnetic resonance imaging (MRI) in the evaluation of diverticulitis will have to be investigated but a more profound integration of this method can already be predicted. Point-of-care ultrasound for initial diagnosis and follow-up assessment will become more important, analogous to FAST in trauma patients.

Thoracic aorta: prospective electrocardiographically triggered CT angiography with dual-source CT--feasibility, image quality, and dose reduction.

PURPOSE: To prospectively investigate the feasibility, image quality, and radiation dose for prospective electrocardiographically (ECG) triggered sequential dual-source computed tomographic (CT) angiography of the thoracic aorta in comparison to retrospective ECG-gated helical dual-source CT angiography. MATERIALS AND METHODS: This study was approved by the institutional review board; informed consent was obtained. One hundred thirty-nine patients referred for ECG-assisted dual-source CT angiography of the thoracic aorta were prospectively enrolled. Inclusion criteria were stable sinus rhythm and heart rate of 80 beats per minute or less. Tube voltage was adjusted to body mass index (< 25.0 kg/m(2), 100 kV, n = 58; > or = 25.0 kg/m(2), 120 kV, n = 81). In both cohorts, patients were randomly assigned to prospective or retrospective ECG-assisted data acquisition. In both groups, tube current (250 mAs per rotation) was centered at 70% of the R-R cycle. The presence of motion or stair-step artifacts of the thoracic aorta was independently assessed by two readers. Effective radiation dose was calculated from the dose-length product. RESULTS: Subjective scoring of motion and stair-step artifacts was equivalent for both techniques. Scan length was not significantly different (23.8 cm +/- 2.4 [standard deviation] vs 23.7 cm +/- 2.5 for prospective and retrospective ECG-triggered CT angiography, respectively; P = .54). Scanning time was significantly longer for prospective ECG-triggered CT angiography (18.8 seconds +/- 3.4 vs 16.4 seconds +/- 3.3, P < .001). Mean estimated effective dose was significantly lower for prospective data acquisition (100 kV, 1.9 mSv +/- 0.5 vs 4.1 mSv +/- 0.7, P < .001; 120 kV, 5.3 mSv +/- 1.1 vs 9.5 mSv +/- 3.0, P < .001). CONCLUSION: Prospective ECG-gated sequential dual-source CT angiography of the thoracic aorta is feasible, despite the slightly longer acquisition time. Thus, motion-free imaging of the thoracic aorta is possible at significantly lower radiation exposure than retrospective ECG-gated helical dual-source CT angiography in certain patients with a regular heart rate.

High-dose chemotherapy and autologous stem-cell transplantation without consolidating radiotherapy as first-line treatment for primary lymphoma of the central nervous system.

Thirteen patients (age 38-67 years) with primary lymphoma of the central nervous system (CNS) were treated with methotrexate and cytarabine/thiotepa induction-chemotherapy followed by high-dose carmustine/thiotepa and autologous stem-cell transplantation. Radiotherapy was restricted to patients who did not respond completely to chemotherapy. With a median follow up of 25 months, 3-year DFS and OS was 77%.

Changes in intra- and extramyocellular lipids in morbidly obese patients after non-surgical weight loss-a pilot study using magnetic resonance spectroscopy.

BACKGROUND & AIMS: Lipid accumulation in muscles is common in obesity and associated with increased risks for insulin resistance. However, the impact of weight loss and exercise on muscle fat content is not clear due to inconsistent data. We used magnetic resonance spectroscopy (MRS) to compare the intra- (IMCL) and extramyocellular lipid (EMCL) proportions in the musculus tibialis anterior of extremely obese patients before and after weight loss. METHODS: Nineteen non-diabetic patients with a Body Mass Index (BMI) ≥ 40 kg/m2 who participated in a non-surgical multimodal weight loss program were recruited. Metabolite ratios of IMCL and EMCL (metabolite/creatine) were assessed using 3 T 1H-MRS before therapy and after 6 months. The primary outcome comprised changes in IMCL and body cell mass. Additionally, changes of IMCL and EMCL were compared with changes in standard clinical measures, i.e., BMI, body composition, blood pressure and functional exercise capacity. RESULTS: After 6 months the relative weight loss was 24.8% (127.6 kg, 48.5 kg/m2 vs. 96 kg, 36.5 kg/m2). All standard clinical measures were significantly improved. MRS data from 10 patients provided complete and evaluable data sets. IMCL was reduced by nearly 50% (p < .05). The reduction of EMCL was not significant (p = .106). An explorative correlation analysis between changes of IMCL and changes of the standard measures did not reveal any significance. CONCLUSIONS: Significant reductions of IMCL following a successful conservative weight loss intervention are detectable by using MRS. These changes may have the potential to serve as an additional marker of clinically meaningful obesity treatment.

Differentiating locally recurrent rectal cancer from scar tissue: Value of diffusion-weighted MRI.

OBJECTIVES: To determine a cut-off apparent diffusion coefficient (ADC) value distinguishing local recurrence from scar tissue in patients with rectal cancer treated with complete surgical tumour removal. METHODS: 72 patients were retrospectively included. Patients underwent 1.5T MRI including multiplanar T2-weighted turbo-spin-echo sequences (TSE) and axial single-shot epi-diffusion-weighted sequences (EPSE). Two independent observers measured mean tumour and scar tissue ADCs by manually drawing regions of interest (ROIs). The t-test and ROC analysis were used for comparison and determining an optimal discrimination threshold. As reference standard histopathological results were used in 23 patients (32%) and clinical follow-up in 49 patients (68%). RESULTS: Recurrent rectal cancer was found in 30 patients (4 female, 26 male, median age 63.13 years) and treatment related changes such as scar tissue in 42 patients (11 female, 31 male, median age 63.67 years). The mean ADC value of tumour recurrence was 1.02×10(-3)mm(2)/s (0.63-1.44×10(-3)mm(2)/s) and of scar tissue 1.77×10(-3)mm(2)/s (1.11-2.41×10(-3)mm(2)/s) showing a statistically significant difference (p<0.001). The cut-off ADC value was 1.34×10(-3)mm(2)/s with a sensitivity, specificity, and accuracy of 93%, 91%, and 92% respectively. CONCLUSIONS: Diffusion weighted MRI allows for the differentiation of tumour recurrence from scar tissue after surgical resection of rectal cancer.

A very rare cause of low-back pain and sciatica: deep vein thrombosis due to absence of the inferior vena cava mimicking the clinical and radiological signs of lumbar disc herniation.

The authors report a very rare cause of low-back pain and sciatica in a patient with iliac vein thrombosis attributed to absence of the infrarenal segment of the inferior vena cava (IVC) with massively dilated venous collaterals draining via a paraspinal plexus into the azygous system. This 21-year-old man presented with acute low-back pain radiating to the left ventral thigh. The initial CT scan revealed an intraspinal lesion that mimicked lumbar disc herniation. Further clarification revealed an iliac vein thrombosis, which was triggered by the absence of the infrarenal segment of the IVC, a very rare vascular anomaly. Collateral venous return was developed and led to lumbar varicosities and epidural vein engorgements. Laboratory examinations revealed factor V mutation as a predisposing factor for thrombosis. The patient's symptoms were relieved with anticoagulation and antiinflammatory therapy. Absence of the infrarenal IVC associated with iliac vein thrombosis should be regarded as a very rare cause of radicular and low-back pain, and this condition can mimic the clinical and radiological signs of lumbar disc herniation. Sciatica might be the first clinical manifestation of this rare venous anomaly.