Contribution of PET imaging to the initial staging and prognosis of patients with Hodgkin's disease.

BACKGROUND: Positron emission tomographic (PET) scanning utilizing [18F]fluorodeoxyglucose (FDG) is a new method of tumor imaging based on the increased glucose metabolic activity of malignant tumors. In Hodgkin's disease (HD), PET has proven value for the evaluation of residual masses following treatment and for the early diagnosis of relapse. In the initial staging of HD, PET frequently shows a higher stage than conventional methods (upstaging by PET). In the present study, we evaluated the frequency of stage changes by PET in a multicenter setting and determined its prognostic relevance. PATIENTS AND METHODS: A total of 73 patients with newly diagnosed HD were staged with both conventional methods and whole-body PET scanning. All histological types and stages were represented. The median time of follow-up after the initial diagnosis was 25 months (range 1 month to 5 years). The response to treatment was determined by standard clinical and diagnostic criteria. For the purpose of this analysis, data from a PET center associated with a university medical center and a PET center associated with a group oncology practice were combined. RESULTS: A total of 21 patients (28.8%) were upstaged by PET compared with conventional methods. In two cases (2.7%), a lower stage was suggested by PET scanning. With one possible exception, the upstaging had no obvious clinical or biological correlate. Among 12 patients in stage I (A + B) by conventional methods, seven were upstaged by PET (58.3%), four to stage II, one to stage III and two to stage IV. Among 42 patients in stage II, eight were upstaged by PET (19.0%), six to stage III and two to stage IV. Among 12 patients in stage III, six (50%) were upstaged to stage IV by PET. If only early-stage patients and major changes are considered (stages IA-IIB to III or IV), among 49, 10 were upstaged to III or IV, whereas in 39 staging was unchanged following PET. In the former group, three relapsed or were refractory compared with none in the latter group (P<0.006). In advanced stage patients (IIIA or IIIB) a trend toward treatment failure was apparent in patients who were upstaged by PET. CONCLUSIONS: PET scanning is an interesting new modality for the accurate staging of patients with HD and frequently shows a higher stage than conventional methods. PET should be performed at initial diagnosis and should be included in prospective studies of patients with HD. Upstaging by PET may represent a risk factor for a more advanced stage or a biologically more aggressive tumor. Patients with early-stage disease as identified by conventional methods have a significant risk of treatment failure if a more advanced stage is indicated by PET. At present, major stage changes suggested by PET imaging should be confirmed by an independent diagnostic method.

Pre-natal diagnosis of occult spinal dysraphism by ultrasonography and post-natal evaluation by MR scanning.

Eight children born with occult spinal dysraphism were diagnosed in utero by ultrasonography. Post-natally, they were evaluated by MR scans. The ultrasound scans in all 8 fetuses revealed a spina bifida: the spinal cord was long in 5 and in 3 a meningocele was thought to be present, however, in 1, a post-natal MR scan revealed a lipomeningocele instead of a simple meningocele. In 3 fetuses an echogenic area was seen on the ultrasound scan which raised the possibility that an intradural lipoma was present, and was confirmed by post-natal MR scans. In 3 fetuses vertebral body anomalies and an additional ossification centre in a midline bony spur together with widening of the spinal canal were seen in the lower lumbar region. The lesions in all 8 fetuses were skin-covered. None had ventriculomegaly or an Arnold-Chiari malformation. The prognosis for fetuses with spina bifida aperta is well documented in contrast to that for those with spina bifida occulta. The ability to identify a spinal dysraphic lesion pre-natally allows a more accurate assessment to be made of the likely outcome for an individual fetus.

The spectrum of spinal cord dysraphism and bladder neuropathy in children.

The frequency of bladder neuropathy and its relationship to abnormalities of the neural axis on MR scan was examined in a group of 49 children with known occult spinal dysraphism and 148 children with daytime urinary incontinence. Of the patients with known spinal dysraphism 55% had bladder neuropathy. There was no relationship between either the type of abnormality or the number of abnormalities seen on MR scan and the presence or absence of bladder neuropathy. 5 of the 9 patients with a normal cord had neuropathic bladders. Four of the 148 patients with daytime wetting turned out to have spinal dysraphism. Of the rest, 51 patients required urodynamic studies and of these 12 had clearcut bladder neuropathy. 15 patients had MR scans, all of which were normal. The range of urodynamic findings in those with bladder neuropathy was identical to the range found in patients with spinal dysraphism. On the basis of these findings it is suggested that children with isolated bladder problems could well have spinal cord dysraphism as a cause of these - the lesions being beyond the resolution of MR scanning. For those children with clearcut spinal dysraphism the absence of any relationship between the bladder findings and the lesion places a question mark over the potential benefits of neurosurgical intervention.