FDG PET/CT for the detection of bone marrow involvement in diffuse large B-cell lymphoma: systematic review and meta-analysis

Purpose

To systematically review and meta-analyse published data on the diagnostic performance of ¹⁸F-FDG PET/CT in detecting bone marrow involvement in patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL).

Methods

PubMed/MEDLINE and Embase were systematically searched for relevant studies. The methodological quality of each study was assessed. Sensitivities and specificities of FDG PET/CT in individual studies were calculated and meta-analysed with a random effects model. A summary receiver operating characteristic curve (sROC) was constructed with the Moses-Shapiro-Littenberg method. Weighted summary proportions of discrepancies between the FDG PET/CT and (blind) bone marrow biopsy (BMB) results among all patients were calculated.

Results

Seven studies, with a total of 654 patients with newly diagnosed DLBCL, were included. Overall, the quality of the included studies was moderate. The sensitivity and specificity of FDG PET/CT for detecting bone marrow involvement ranged from 70.8 % to 95.8 % and from 99.0 % to 100 %, with pooled estimates of 88.7 % (95 % confidence interval, CI, 82.5 – 93.3 %) and 99.8 % (95 % CI 98.8 – 100 %), respectively. The area under the sROC curve was 0.9983. The weighted summary proportion of FDG PET/CT-negative patients with positive BMB findings among all patients was 3.1 % (95 % CI 1.8 – 5.0 %) and the weighted summary proportion of FDG PET/CT-positive patients with negative BMB findings among all patients was 12.5 % (95 % CI 8.4 – 17.3 %).

Conclusion

FDG PET/CT is accurate and complementary to BMB for detecting bone marrow involvement in patients with newly diagnosed DLBCL. A negative FDG PET/CT scan cannot rule out the presence of bone marrow involvement, but positive FDG PET/CT findings obviate the need for BMB for the detection of bone marrow involvement in these patients.     

Whole-body MRI vs. CT for staging lymphoma: Patient experience

Objective

To assess and compare patient experience of whole-body magnetic resonance imaging (MRI) to that of computed tomography (CT) for staging newly diagnosed lymphoma.

Materials and methods

A total of 36 patients with newly diagnosed lymphoma prospectively underwent whole-body MRI and CT for staging purposes. Patients were asked to fill in a short questionnaire with regard to the burden and experience of the examination on a Likert scale (range 1–4). Wilcoxon signed rank tests were used to determine statistically significant differences in patient (dis)comfort between the two examinations.

Results

Patients reported to be significantly (P = 0.007) less worried before undergoing whole-body MRI compared to CT. Patients also experienced whole-body MRI as significantly (P = 0.010) less unpleasant and felt significantly (P = 0.003) better shortly after the scan. The necessary preparations before CT scanning (i.e. insertion of intravenous line, drinking of contrast fluid), which are not required for whole-body MRI, were reported to be a considerable burden.

Conclusion

In this study in patients with newly diagnosed lymphoma, whole-body MRI was experienced as a more patient-friendly technique than CT.     

The role of platelet membrane glycoproteins Ib and IIb-IIIa in platelet adherence to human artery subendothelium

Platelet adherence to human artery subendothelium in blood from eight normal subjects, four patients with Glanzmann's thrombasthenia (deficiency of platelet membrane glycoproteins IIb and IIIa: GPIIb-IIIa), two patients with Bernard-Soulier syndrome (deficiency of platelet membrane glycoprotein Ib: GPIb) and one patient with von Willebrand's disease (VWD subtype III. deficient in factor VIII-von Willebrand factor: FVIII-VWF) was compared at various wall shear rates (300, 500, 1000, 1800 and 2500 s-1). Platelet adherence in blood from the patients with Glanzmann's thrombasthenia was within the normal range at shear rates below 1000 s-1. There was some decrease in adhesion at higher shear rates and platelets were less spread out on the subendothelium than normally at all shear rates. Platelet aggregate formation was almost totally absent. Platelet adherence in blood from patients with the Bernard-Soulier syndrome was strongly impaired at all shear rates. Platelet adherence in blood from the patient with VWD subtype III was normal at shear rates of 300 and 500 s-1, but impaired at shear rates above 1000 s-1. Aggregate formation was also decreased at these shear rates. Platelet adhesion was strongly inhibited by a monoclonal antibody against glycoprotein Ib, which had previously been shown to inhibit ristocetin-induced aggregation, at shear rates of 500 and 1800 s-1 but not at 300 s-1. Platelet adhesion at 1800 s-1 was also inhibited, though to a lesser extent, by two antibodies against GPIIb-IIIa. These antibodies also inhibited platelet aggregate formation. The data indicates that GPIb is involved in adhesion at the same shear rates as von Willebrand factor. Absence or inhibition of GPIIb-IIIa primarily causes a defect of aggregate formation but GPIIb-IIIa may also play a role in adhesion, particularly at high shear rates. The defect of adhesion in the Bernard-Soulier syndrome may be dependent on factors other than a deficiency of GPIb alone.     

Glycoprotein IIb-IIIa and RGD(S) are not important for fibronectin- dependent platelet adhesion under flow conditions

Previous studies have indicated that activated blood platelets interact with fibronectin through binding of fibronectin to the glycoprotein IIb- IIIa complex (GPIIb-IIIa). The cell attachment site of fibronectin with its crucial arg-gly-asp(-ser) [RGD(S)]sequence is involved in these bindings. We studied the importance of these interactions for the fibronectin dependence of platelet adhesion under flow conditions. An RGDS-containing hexapeptide (GRGDSP) was compared with a nonreactive control peptide (GRGESP). The GRGDSP-peptide inhibited thrombin-induced aggregation and adhesion under static conditions at 0.1 mmol/L. This concentration had no effect on platelet adhesion to nonfibrillar collagen type I in flow. GRGDSP at 1 mmol/L had a significant inhibitory effect at 1,500 s-1, but not at the lower shear rates of 800 and 300 s-1 where platelet adhesion is also fibronectin dependent. On the matrix of cultured human umbilical vein endothelial cells, 1 mmol/L GRGDSP had no effect on platelet adhesion. The relation between GPIIb- IIIa and fibronectin dependence was investigated with platelets of a patient with Glanzmann's thrombasthenia and monoclonal antibodies to GPIIb-IIIa using endothelial cell matrix (ECM) as a surface. Platelets of normal controls or a patient with Glanzmann's thrombasthenia showed a similar inhibition of adhesion in the presence of fibronectin-free plasma after the ECMs had been preincubated with antifibronectin F(ab')2 fragments. Incubation of platelets with anti-GPIIb-IIIa showed inhibition of platelet adhesion at high shear rates. Dependence on fibronectin for platelet adhesion was still observed even though separate experiments had shown that these anti-GPIIb-IIIa antibodies could block binding of radiolabeled fibronectin to thrombin-activated platelets. These data suggest the existence of another binding system for the interaction of platelets with fibronectin that may only appear when fibronectin is present on a surface.     

Radiological findings in autistic and developmentally delayed children

PURPOSE: The aim of this study was to evaluate the prevalence of brain abnormalities in a group of young children with developmental disorders, specifically including children that came to the attention of a child psychiatrist before the age of 3 years. METHODS: Forty-five children participated in an MR study (mean age 43 months, SD=12, four females). The study design was approved by the local Medical Ethical Review Board. All parents gave written informed consent. Scans were independently assessed by two board-certified radiologists for malformations of gray and white matter. RESULTS: Cohen's kappa for the consensus between the two raters was 0.79. In 22 children (49%) abnormalities were reported. Four patients (8.5%) had an arachnoid cyst. One female was diagnosed with a Chiari I malformation. Three children show enlarged Virchow-Robin spaces, an increased occurrence when compared to the normal population. CONCLUSIONS: A high rate of intracranial abnormalities was found in this study. Radiological findings do not contribute to the diagnosis of developmental disorders. However, young children with developmental disorders may not be able to express discomfort associated with brain abnormalities, such as a Chiari I malformation. Given the high prevalence of abnormalities in this sample neuroimaging may be a useful tool in clinically assessing children with developmental disorders.     

MR of the caudal regression syndrome: embryologic implications.

PURPOSETo evaluate the spectrum of developmental anomalies observed in patients with the caudal regression syndrome and relate them to the pathogenesis of this syndrome.METHODSNineteen children with caudal regression were investigated with MR.RESULTSThe level of vertebral agenesis varied from T-11 to S-5. In 9 of the 19 children the characteristic high-ending wedge-shaped cord terminus was observed. A separation of the anterior and posterior spinal roots of the cauda equina was observed in 9 patients. Four patients had a tethered spinal cord, in 1 in combination with a wedge-shaped cord terminus.CONCLUSIONSThe pathogenesis of the caudal regression syndrome can be divided into two kinds: there is usually a disturbance of the primary neurulation process; in other cases there is a derailment of the process of degeneration and differentiation of an initially normally developed primary and secondary neural tube. MR aids understanding of the morphology and pathogenesis of congenital malformations involved (including the associated anomalies of the genitourinary and gastrointestinal systems), but other studies are still necessary to determine the exact mechanism of this syndrome.     

Magnetic resonance imaging of malignant lymphoma

Computed tomography (CT), (18)F-fluorodeoxyglucose (FDG)-PET and the hybrid FDG-PET/CT are the most commonly used diagnostic tools for the initial staging and treatment response assessment of malignant lymphomas. MRI techniques such as whole-body MRI and diffusion-weighted imaging may be good radiation-free alternatives to FDG-PET/CT, which may be particularly relevant for children. Diffusion-weighted imaging is characterized by high sensitivity for the detection of lesions and allows quantitative assessment of diffusion that may aid in the evaluation of malignant lymphomas. This article will review the value of these emerging MRI techniques for the staging and response assessment of malignant lymphoma. Furthermore, we will discuss some additional imaging techniques that are the subject of ongoing research and may have potential for future clinical application.     

Hepatobiliary and pancreatic imaging in children—techniques and an overview of non-neoplastic disease entities

Imaging plays a major role in the diagnostic work-up of children with hepatobiliary or pancreatic diseases. It consists mainly of US, CT and MRI, with US and MRI being the preferred imaging modalities because of the lack of ionizing radiation. In this review the technique of US, CT and MRI in children will be addressed, followed by a comprehensive overview of the imaging characteristics of several hepatobiliary and pancreatic disease entities most common in the paediatric age group.