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A three‐dimensional (3)D spiral sequence was developed for dynamic breast magnetic resonance (MR) imaging with much improved image quality. Partial Z phase encoding was applied to obtain thinner slices for a coverage of the whole breast. Comparison between the 3D and a previously developed multi‐slice 2D spiral sequences was performed on ten healthy volunteers without contrast and five breast patients with gadolinium‐diethylene triamine pentaacetic acid (Gd‐DTPA). The 3D spiral images had significantly less off‐resonance blurring and spiral artifacts. With a small compromise on temporal resolution (7.7 seconds in 2D and 10.6 seconds in 3D), we obtained 32 interpolated 3–5 mm slices (with 20 Z phase encodes) for a full coverage of 10–16 cm breast with the same 1 × 1 mm2in‐plane resolution as the 2D sequence, which haad 12 8–13 mm slices. Contrast between glandular and soft tissue in normal breasts was increased by about 25%. The reduced repetition time in the 3D spiral acquisition led to an increased Gd‐enhanced signal. The difference between the enhancement of malignant and benign lesions increased by sevenfold. We expect that this new development could lead to improved specificity in characterizing breast lesions using MR imaging. J. Magn. Reson. Imaging 2000;11:351–359. © 2000 Wiley‐Liss, Inc.

SUMMARY With increasing frequency, cellular organelles and nuclear structures are being investigated at high resolution using electron microscopic tomography of thick sections (0·3–1·0 μm). In order to reconstruct the structures in three dimensions accurately from the observed image intensities, it is essential to understand the relationship between the image intensity and the specimen mass density. The imaging of thick specimens is complicated by the large fraction of multiple scattering which gives rise to incoherent and partially coherent image components. Here we investigate the mechanism of image formation for thick biological specimens at 200 and 300 keV in order to resolve the coherent scattering component from the incoherent (multiple scattering) components. Two techniques were used: electron energy‐loss spectroscopic imaging (ESI) and exit wavefront reconstruction using a through‐focus series. Although it is commonly assumed that image formation of thick specimens is dominated by amplitude (absorption) contrast, we have found that for conventionally stained biological specimens phase contrast contributes significantly, and that at resolutions better than ∼10 nm, superposed phase contrast dominates. It is shown that the decrease in coherent scattering with specimen thickness is directly related to the increase in multiple scattering. It is further shown that exit wavefront reconstruction can exclude the microscope aberrations as well as the multiple scattering component from the image formation. Since most of the inelastic scattering with these thick specimens is actually multiple inelastic scattering, it is demonstrated that exit wavefront reconstruction can act as a partial energy filter. By virtue of excluding the multiple scattering, the ‘restored’ images display enhanced contrast and resolution. These findings have direct implications for the three‐dimensional reconstruction of thick biological specimens, where a simple direct relationship between image intensity and mass density was assumed, and the aberrations were left uncorrected.

Non-tuberculous mycobacteria are becoming increasingly important pathogens among transplant recipients. We report a case of disseminated Mycobacterium haemophilum infection in a heart transplant recipient, manifesting as cellulitis, subcutaneous nodules, septic arthritis, and pneumonitis. Our case illustrates diverse challenges in the identification and treatment of this pathogen, such as its unique culture requirements and variable antimicrobial susceptibilities. Heightened clinical suspicion is necessary to establish a timely diagnosis so that optimal treatment can be administered.

Erythrokeratoderma variabilis, also known as Mendes da Costa syndrome, is a genodermatosis belonging to the group of diseases known as the erythrokeratodermias. Erythrokeratoderma variabilis is characterized by two distinctive manifestations: well-demarcated, variable, transient, figurate patches of erythema, and localized or generalized hyperkeratotic plaques. Treatments include topical retinoic acid, salicylic acid, and alpha-hydroxy acid in petrolatum, but all have been reported to have limited, variable success rates. We report a child with erythrokeratoderma variabilis with no family history of this entity, successfully treated with topical tazarotene.