White matter fiber tractography and color mapping of the normal human cerebellum with diffusion tensor imaging

Diffusion tensor imaging (DTI) color mapping and fiber tractography was used to study the white matter within the cerebellum along with the afferent and efferent tracts associated with the cerebellum in 24 normal human subjects. The most prominent structures that can be readily identified using these DTI techniques are the middle, inferior and superior cerebellar peduncles. Furthermore DTI shows transverse white matter fiber that cross between the two cerebellar hemispheres at the level of the vermis. At the hemispheric level fibers to the dentate, to the emboliform nuclei are clearly visible on DTI as is the afferent pathway represented by the middle cerebellar peduncle. Selective DTI fiber tractography provides very exquisite images of the cerebellar peduncles and of the fibers projecting to and from the cerebellar cortex. This study demonstrates that DTI is complementary to conventional MRI in that DTI elucidates the orientation of white matter fiber bundles that are associated with the cerebellum. Therefore we anticipate that DTI will become an important adjunct to conventional MRI for clinical and basic studies of cerebellar ataxias and congenital disorders involving the cerebellum and brain stem. This work provides a summary of the normal DTI appearance of the cerebellar white matter which will be useful for interpreting DTI results in clinical populations.

Pulmonary thromboendarterectomy in a case of hereditary stomatocytosis

We present a case of pulmonary thromboendarterectomy performed successfully in a patient with stomatocytosis. Stomatocytosis is a rare condition of abnormal erythrocyte morphology in which haemolysis and hyperkalaemia occur at cooler temperatures. A 35-yr-old male with stomatocytosis was referred for pulmonary thromboendarterectomy in the context of chronic thromboembolic pulmonary hypertension. He had undergone splenectomy as a child, which rendered him hypercoagulable as the spleen normally removes the haemolysed red cell fragments from blood. By constantly monitoring urine for macroscopic haematuria, arterial and mixed venous blood gas analysis perioperatively and by limiting the period of deep hypothermic circulatory arrest that is normally required for this operation, we were able to perform the operation successfully.

Outcome of transplantation using kidneys from controlled (Maastricht category 3) non-heart-beating donors

BACKGROUND

Many renal transplant centres are reluctant to use kidneys from non-heart-beating (NHB) donors because of the high incidence of primary non-function and delayed graft function reported in the literature. Here, we report our favourable experience of using kidneys from Maastricht category 3 donors (controlled NHB donors).

MATERIALS AND METHODS

From January 1996 to June 2002, 42 renal transplants using kidneys from 25 controlled NHB donors were undertaken at our centre. The rates of primary non-function, delayed graft function (DGF), rejection and long-term graft and patient survival were compared with those of 84 recipients of grafts from heart-beating (HB donors) transplanted contemporaneously.

RESULTS

Primary non-function did not occur in recipients of grafts from NHB donors but was seen in two grafts from HB donors. DGF occurred in 21 of 42 (50%) kidneys from NHB donors and 14 of 84 (17%) kidneys from HBD donars (p < 0.001). The acute rejection rates in the two groups were similar (33% for grafts from NHB donors vs. 40% from HB donors). By 1 month after transplantation, there was no significant difference in serum creatinine concentration between the two groups. Over a median follow-up period of 32 months (range 2-75 months), the actuarial graft survival rates at 1, 3 and 5 yr after transplantation were 84, 80 and 74% for recipients of kidneys from NHB donors, compared with 89, 85 and 80% for kidneys from HB donors.

CONCLUSION

Controlled NHB donors are a valuable and under-used source of kidneys for renal transplantation. The outcome for recipients of kidney allografts from category 3 NHB donors is similar to that seen in recipients of grafts from conventional HB cadaveric donors.