Bernd Hamm

Does ultra-low-dose CT with a radiation dose equivalent to that of KUB suffice to detect renal and ureteral calculi?

The objective of this study was to evaluate the diagnostic yield of multislice CT using a radiation dose equivalent to that of conventional abdominal x-ray (KUB). One hundred forty-two patients were prospectively examined with ultrasound and a radically dose-reduced CT protocol (120 kV, 6.9 eff. mAs). Number and size of calculi, presence of urinary obstruction, and alternative diagnoses were recorded and confirmed by stone removal/discharge or by clinical and imaging follow-up. The mean effective whole-body dose was 0.5 mSv in men and 0.7 mSv in women. The sensitivity and specificity in detecting patients with calculi was 97% and 95% for CT and 67% and 90% for ultrasound. Urinary obstruction was similarly assessed, whereas CT identified significantly more alternative diagnoses than ultrasound (P < 0.001). With regard to published data for standard-dose CT, the present CT protocol seems to be comparable in its diagnostic yield in assessing patients with calculi, and its radiation dose is equivalent to that of KUB.

Combination of free-breathing and breathhold steady-state free precession magnetic resonance angiography for detection of coronary artery stenoses

To analyze the incremental diagnostic value of a combination of two approaches (free‐breathing and breathhold) vs. the sole free‐breathing approach to coronary magnetic resonance angiography (CMRA) for detection of significant stenoses.

Multisegment and halfscan reconstruction of 16-slice computed tomography for assessment of regional and global left ventricular myocardial function.

Rationale and Objectives:We sought to prospectively compare multisegment and halfscan reconstruction of 16-slice computed tomography (CT) for the assessment of regional and global left ventricular myocardial function with magnetic resonance imaging (MRI) as the reference standard. Materials and Methods:Forty-two patients underwent CT with 16 × 0.5-mm detector collimation. Electrocardiogram-gated reconstructions were generated with multisegment reconstruction (using up to 4 segments correlated with the raw data of up to 4 heartbeats) and standard halfscan reconstruction. Steady-state free-precession cine MRI was acquired within 24 hours. Results:More normal myocardial segments were identified correctly with multisegment (95%, 620/656) compared with halfscan reconstruction (88%, 582/656) of CT (P < 0.001). Also, the accuracy (92% [657/714] vs. 87% [620/714]) and rate of nondiagnostic segments (0% vs. 5% [33/714]) were significantly better when using multisegment reconstruction (P < 0.001). The image quality with multisegment reconstruction was significantly superior to that achieved with halfscan reconstruction (P < 0.001). In the assessment of global left ventricular function, multisegment and halfscan reconstruction of CT showed high correlations for all parameters with MRI, whereas Bland-Altman analysis revealed smaller limits of agreement for assessment of myocardial mass with multisegment reconstruction (P = 0.025), but no significant differences between both reconstruction techniques in the measurement of left ventricular volumes as compared with MRI. Conclusions:Multisegment reconstruction of 16-detector row CT improves image quality and assessment of regional wall motion compared with standard halfscan reconstruction.

Low‐field MRI for assessing synovitis in patients with rheumatoid arthritis. Impact of Gd‐DTPA dose on synovitis scoring

Objective: To investigate the impact of a double dose compared to a single dose of contrast material in low‐field magnetic resonance imaging (MRI) on semi‐quantitative scoring of synovitis in patients with rheumatoid arthritis (RA). Methods: This prospective study included 38 RA patients (23 women and 15 men, mean age 51 years). All patients underwent low‐field MRI of the hand before administration of contrast medium, after intravenous injection of 0.1 mmol/kg gadolinium diethylenetriaminepentaacetic acid (Gd‐DTPA), and after another dose of 0.1 mmol/kg Gd‐DTPA. Two readers (A and B) blinded to dosage independently scored the single dose and double dose image sets for synovitis according to outcome measures in rheumatology (OMERACT) recommendations. Contrast‐to‐noise ratio (CNR) and signal‐to‐noise ratio (SNR) were also calculated for each set. Results: 149 metacarpophalangeal (MCP) joints were evaluated. There was good inter‐reader agreement for each of the two sets (intra‐class correlation coefficient of 0.75 for the single dose set and 0.83 for the double dose). Median CNR and SNR values were 5.4 and 15.9, respectively, for the single dose set and 8.5 and 16.6, respectively, for the double dose set (p<0.0001). Single dose set mean synovitis scores were 1.7 and 1.6 for readers A and B, respectively. Double dose set scores were 1.9 and 2.0, respectively. Thus, higher synovitis scores were recorded for the double dose sets than the single dose sets (p<0.005). Conclusion: In low‐field MRI, when evaluating RA, the dose of the contrast material influences synovitis scoring. Therefore, dosage of contrast material should be taken into consideration when using extremity dedicated low‐field MRI.

Respiratory-triggered MRCP applying parallel acquisition techniques.

To evaluate the influence of parallel imaging on the image quality of respiratory triggered magnetic resonance cholangiopancreatography (MRCP).

Percutaneous discography: comparison of low-dose CT, fluoroscopy and MRI in the diagnosis of lumbar disc disruption

Aim: To compare the diagnostic accuracy of low-dose computed tomography (CT), magnetic resonance imaging (MRI) and fluoroscopy in percutaneous discography in patients scheduled for lumbar spondylodesis. Material and methods: Within a prospective pilot study, 18 disc segments of 11 patients with radicular or pseudoradicular pain prior to anteroposterior spondylodesis were evaluated. After injection of a mixture of non-ionic iodine-containing contrast agent and gadolinium-based contrast medium into the disc spaces, all patients underwent conventional fluoroscopy, as well as low-dose CT and MRI. The occurrence of memory pain during contrast injection was recorded. CT, MRI and fluoroscopic images were analyzed independently by two readers blinded to the clinical findings. Results: There was 100% agreement between CT and MRI discography in the detection, localization and grading of degenerative changes. In contrast, conventional fluoroscopy identified only 9 of the 12 abnormal segments. Memory pain following puncture was identified in 3 of the 12 affected segments. Summary: Low-dose CT and MRI discography have a similar accuracy in the assessment of disc disruption and they are superior to fluoroscopic discography.

Formalin-fixed blood clots- : Additional histological findings on computed tomography-guided fine-needle aspiration biopsies in comparison with core biopsies

Objective: We investigated the diagnostic yield of histological examined formalin-fixed blood clots (FFBCs) in comparison with the established procedures of fine-needle aspiration biopsy (FNAB) and core biopsy (CB) obtained by percutaneous puncture under computed tomography (CT) guidance. Methods: A total of 76 CT-guided punctures with removal of tissue by means of all 3 different techniques (FFBC, FNAB, and CB) were performed. Specimens were obtained from the lung (n = 18), mediastinum (n = 10), upper abdominal organs (n = 32), pelvis (n = 4), retroperitoneum (n = 4), bones (n = 7), and neck (n = 1). All results were correlated with the clinical course of the patients (minimum, 6 months; mean period, 10 months). The results of each technique were compared. Results of a combined use of FFBC and FNAB were analyzed. Results: The overall sensitivity (regardless of biopsy site) was 79% for FFBC, 83% for FNAB, and 95% for CB. In chest biopsies, FFBC reached a sensitivity of 92%, FNAB of 86%, and CB of 96%. In liver biopsies, the sensitivities were 47%, 70%, and 88% for FFBC, FNAB, and CB and, for the remaining biopsy sites, 90%, 90%, and 100%, respectively. The combination of FFBC and FNAB showed higher sensitivities than FFBC and FNAB alone. Overall sensitivity for the combination was 88%, with 92%, 72%, and 100% for thorax, liver, and other locations. A definitive diagnosis was made by FFBC in 87% of cases, by FNAB in 74%, and by CB in 88%. The combination of FFBC and FNAB showed a definite diagnosis in 90% of the cases. A tentative diagnosis has been established in 12%, 7%, 5%, and 4%, respectively. In 4 cases (5%), all 3 techniques failed to yield reliable diagnoses. Conclusions: The examination of FFBCs is a useful supplement to the established technique of CT biopsy. In combination with FNAB, FFBC has a comparable sensitivity as CB in chest punctures and other extrahepatic lesions.

Magnetic resonance imaging findings of basal cell adenoma in Curschmann-Steinert myotonic dystrophy.

Myotonic dystrophy Curschmann Steinert is a common hereditary disorder that in some cases can be combined with cutaneous tumors, which is an association that is rarely described in the literature. We present the magnetic resonance imaging in the unusual combination of a patient with known myotonic dystrophy and recurrent basal cell tumor.