Sclerosing mesenteritis and mesenteric panniculitis - clinical experience and radiological features.

BACKGROUND: Sclerosing mesenteritis (SM) is sometimes used as an umbrella-term for idiopathic inflammatory conditions in the mesentery. Mesenteric panniculitis (MP) is a radiological finding and its relation to clinical SM is not fully understood. The aims of this study were to determine whether any correlation could be found between the radiological findings and the clinical disease course. METHODS: Patients observed due to idiopathic inflammation of the mesentery were identified. If SM could be verified histologically or MP radiologically, the patients were included in this descriptive retro perspective study. RESULTS: Typical radiological changes were observed in 27 patients. A majority (23/27) of these patients had mild to moderate symptoms. This group with typical radiology was labelled MP. Four patients were included due to histologically verified disease but had uncharacteristic radiology involving multiple compartments of the abdomen. All four had marked systemic inflammation, fever and fluctuating radiologic findings. Three had severe disease with multiple hospitalisations and complications but responded promptly to corticosteroids. This group was denoted SM. CONCLUSIONS: We have identified two subgroups of patients; firstly, MP with stable and characteristic radiologic changes and secondly SM with atypical radiology and a more aggressive clinical course. We propose that the term SM should be reserved for this latter condition.

Low-dose radiation with 80-kVp computed tomography to diagnose pulmonary embolism: a feasibility study.

BACKGROUND: Mounting collective radiation doses from computed tomography (CT) implies an increased risk of radiation-induced cancer in exposed populations, especially in the young. PURPOSE: To evaluate radiation dose and image quality at 80-kVp CT to diagnose acute pulmonary embolism (PE) compared with a previous study at 100 and 120 kVp with all other scanning parameters unchanged. MATERIAL AND METHODS: A custom-made chest phantom with a 12 mg I/mL-syringe was scanned at 80/100/120 kVp to evaluate relative changes in computed tomographic dose index (CTDI(vol)), attenuation, image noise, and contrast-to-noise ratio (CNR). Fifty patients underwent 80 kVp 16-row detector CT at 100 "Quality reference" mAs. A total of 350 mg I/kg were injected to compensate for increased CNR at 80 kVp, while 300 mg I/kg had been used at 100/120 kVp. CTDI(vol), dose-length product (DLP), and estimated effective dose were evaluated including Monte Carlo simulations. Pulmonary artery attenuation and noise were measured and CNR calculated. Two radiologists evaluated subjective image quality using a four-grade scale. RESULTS: Switching from 120 to 80 kVp in the phantom study decreased radiation dose by 67% while attenuation and noise increased 1.6 and 2.0 times, respectively, and CNR decreased by 16%. Switching from 120 to 80 kVp in the patient studies decreased estimated effective dose from 4.0 to 1.2 mSv (70% decrease) in median while pulmonary artery attenuation and noise roughly doubled from 332 to 653 HU and from 22 to 49 HU, respectively, resulting in similar CNR (13 vs. 12). At 80 kVp all examinations were regarded as adequate (8%) or excellent (92%). CONCLUSION: Switching from 120 to 80 kVp CT without increased mAs but slightly increased iodine dose may be of special benefit to diagnose PE in younger individuals with preserved renal function where the primary aim is to minimize radiation dose and reaching levels below that of scintigraphy.

Using 100- instead of 120-kVp computed tomography to diagnose pulmonary embolism almost halves the radiation dose with preserved diagnostic quality.

BACKGROUND: Concern has been raised regarding the mounting collective radiation doses from computed tomography (CT), increasing the risk of radiation-induced cancers in exposed populations. PURPOSE: To compare radiation dose and image quality in a chest phantom and in patients for the diagnosis of pulmonary embolism (PE) at 100 and 120 peak kilovoltage (kVp) using 16-multichannel detector computed tomography (MDCT). MATERIAL AND METHODS: A 20-ml syringe containing 12 mg I/ml was scanned in a chest phantom at 100/120 kVp and 25 milliampere seconds (mAs). Consecutive patients underwent 100 kVp (n = 50) and 120 kVp (n = 50) 16-MDCT using a "quality reference" effective mAs of 100, 300 mg I/kg, and a 12-s injection duration. Attenuation (CT number), image noise (1 standard deviation), and contrast-to-noise ratio (CNR; fresh clot = 70 HU) of the contrast medium syringe and pulmonary arteries were evaluated on 3-mm-thick slices. Subjective image quality was assessed. Computed tomography dose index (CTDI(vol)) and dose-length product (DLP) were presented by the CT software, and effective dose was estimated. RESULTS: Mean values in the chest phantom and patients changed as follows when X-ray tube potential decreased from 120 to 100 kVp: attenuation +23% and +40%, noise +38% and +48%, CNR -6% and 0%, and CTDI(vol) -38% and -40%, respectively. Mean DLP and effective dose in the patients decreased by 42% and 45%, respectively. Subjective image quality was excellent or adequate in 49/48 patients at 100/120 kVp. No patient with a negative CT had any thromboembolism diagnosed during 3-month follow-up. CONCLUSION: By reducing X-ray tube potential from 120 to 100 kVp, while keeping all other scanning parameters unchanged, the radiation dose to the patient may be almost halved without deterioration of diagnostic quality, which may be of particular benefit in young individuals.