ARRS 2022 Abstracts

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E1427. Imaging Characteristics and Atypical Locations of Calcium Hydroxyapatite Deposition Disease: A Guide for the General Radiologist
Authors
  1. Justin Hungerford; Albany Medical Center
  2. Lee Thompson; Albany Medical Center
  3. Erik Jacobson; Albany Medical Center
  4. Michael Cooley; Community Care Phyicians
Background
Calcium hydroxyapatite deposition disease (HADD) refers to a process of calcium deposition in soft tissues and bone that is a common periarticular finding in middle-aged persons. HADD is most prevalent in the supraspinatus and, to a lesser extent, the infraspinatus tendons of the rotator cuff near the insertion on the humeral head. Most patients with rotator cuff deposition are asymptomatic. However, HADD may affect any joint and may also cause severe acute inflammation and pain.

Educational Goals / Teaching Points
The goal of this presentation is to identify the typical imaging features of HADD across multiple modalities and highlight uncommon locations of disease to aid in confident identification by the general radiologist.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
There is no clear pathogenesis for HADD, but a simplified two-stage model has been described in the literature. The formative stage represents calcium deposition in tissues, which may be stable in appearance for variable lengths of time and are often asymptomatic. In some cases, these more stable deposits may also be associated with chronic pain secondary to impingement. The calcifications are typically well-defined and homogenous. The resorptive phase represents rupture into adjacent soft tissues or bursae and is suspected to cause an acute inflammatory response, resulting in significant pain and reduced range of motion. This acute phase is often associated with radiographic findings of more hazy, ill-defined, and heterogeneous calcific densities that may accumulate rapidly or exhibit migration on successive imaging. Radiography is the initial imaging of choice for detecting calcifications. CT may be more helpful in differentiating more subtle features of HADD from other calcific arthropathies and can identify any associated cortical erosion. Doppler ultrasound is useful in differentiating calcium hydroxyapatite with typical associated vascularity from non-vascular degenerative calcifications. In isolation, MRI can be problematic in diagnosing HADD as the source of inflammation.In conjunction with radiographs, MRI is useful to evaluate the extent of involved tissues and detecting calcium migration.

Conclusion
HADD, particularly in atypical locations, may cause uncertainty in radiographic diagnosis and lead to delayed or unnecessary care. It is important to accurately diagnose this disease as it is typically self-limiting and often treated with conservative management. Importantly, there are imaging features that can differentiate HADD from more worrisome processes, such as joint infection or neoplasm.