Pixelized Measurement of (99m)Tc-HDP Micro Particles Formed in Gamma Correction Phantom Pinhole Scan: a Reference Study

Precise differential diagnosis of acute bone marrow edema and hemorrhage and trabecular microfractures using naïve and gamma correction pinhole bone scans

Objective

To analyze the performance of sequential naïve pinhole bone scan (nPBS) and gamma correction pinhole bone scan (GCPBS), reinforced by ImageJ densitometry and pixelized microfracture measurement, for making specific diagnoses of bone marrow edema (BME), bone marrow hemorrhage (BMH), and trabecular microfractures (TMF).

Methods

We prospectively examined BME, BMH, TMF, and normal trabeculae in 10 patients using sequential nPBS and GCPBS. The intensity of ^99mtechnetium-hydroxydiphosphonate (^99mTc-HDP) uptake was measured using a pixelized method and calculated using ImageJ densitometry in terms of arbitrary units (AU). This overall method was termed a visuospatial-mathematic assay (VSMA). We analyzed the ability of the calculated AU values to discriminate between the four states using GraphPad Prism software, with reference to previous morphological data.

Results

The calculated values were categorized as ≤50 AU for normal trabecula, 51–100 AU for BME, 101–150 AU for BMH, and ≥151 AU for TMF. The difference in uptake between normal trabecula and BME was significant and the differences among BME, BMH, and TMF were highly significant.

Conclusion

VSMA is a useful technique for refining objective individual diagnoses and for differentiating and quantitating BME, BMH, and TMF.

Morphobiochemical diagnosis of acute trabecular microfractures using gamma correction Tc-99m HDP pinhole bone scan with histopathological verification

We prospectively performed gamma correction pinhole bone scan (GCPBS) and histopathologic verification study to make simultaneous morphobiochemical diagnosis of trabecular microfractures (TMF) occurred in the femoral head as a part of femoral neck fracture.Materials consisted of surgical specimens of the femoral head in 6 consecutive patients. The specimens were imaged using Tc-99m hydroxymethylene diphosphonate (HDP) pinhole scan and processed by the gamma correction. After cleansing with 10% formalin solution, injured specimen surface was observed using a surgical microscope to record TMF. Morphological findings shown in the photograph, naive pinhole bone scan, GCPBS, and hematoxylin-eosin (H&E) stain of the specimen were reciprocally correlated for histological verification and the usefulness of suppression and enhancement of Tc-99m HDP uptake was biochemically investigated in TMF and edema and hemorrhage using gamma correction.On the one hand, GCPBS was able to depict the calcifying calluses in TMF with enhanced Tc-99m HDP uptake. They were pinpointed, speckled, round, ovoid, rod-like, geographic, and crushed in shape. The smallest callus measured was 0.23 mm in this series. On the other hand, GCPBS biochemically was able to discern the calluses with enhanced high Tc-99m HDP uptake from the normal and edema dipped and hemorrhage irritated trabeculae with washed out uptake.Morphobiochemically, GCPBS can clearly depict microfractures in the femoral head produced by femoral neck fracture. It discerns the microcalluses with enhanced Tc-99m HDP uptake from the intact and edema dipped and hemorrhage irritated trabeculae with suppressed washed out Tc-99m HDP uptake. Both conventional pinhole bone scan and gamma correction are useful imaging means to specifically diagnose the microcalluses naturally formed in TMF.