The Shepherd's Crook Sign: A New Neuroimaging Pareidolia in Joubert Syndrome

Radiological features of Joubert syndrome and clinical case presentation

Joubert Syndrome, manifests in a spectrum of neurological symptoms. This case describes a 7-year-old girl with perinatal complications, and subsequent neurodevelopmental challenges. An MRI confirmed the diagnosis of Joubert syndrome, with the distinctive "molar tooth sign" being a key imaging characteristic. Approximately 25% of cases exhibit nephronophthisis, impacting kidney function, further complicating the clinical picture. Diagnosis relies on imaging and management necessitates a multidisciplinary approach, addressing symptoms and complications, with prognosis linked to the presence of organic disease. The case emphasizes the significance of a multidisciplinary strategy, including genetic counseling, and underscores the diverse manifestations of this syndrome. Prenatal identification through ultrasound and MRI plays a crucial role in diagnosing and treating this rare condition.

Radiological Features of Joubert's Syndrome

Joubert syndrome (JS) is a rare autosomal recessive disorder. All patients affected by this syndrome presented a characteristic picture of cranial fossa malformations, called “molar tooth sign.” This sign is defined by the presence in axial section at the level of a deck/midbrain, of hypo/dysplasia of the cerebellar vermis, abnormally deep interpeduncular fossa and horizontalized thickened and elongated superior cerebellar peduncles. Although “molar tooth sign” is peculiar of JS, other radiological findings have been also reported in these patients. Here, the authors briefly assumed the principal magnetic resonance imaging findings of JS.

Visual Illusions in Radiology: Untrue Perceptions in Medical Images and Their Implications for Diagnostic Accuracy

Errors in radiologic interpretation are largely the result of failures of perception. This remains true despite the increasing use of computer-aided detection and diagnosis. We surveyed the literature on visual illusions during the viewing of radiologic images. Misperception of anatomical structures is a potential cause of error that can lead to patient harm if disease is seen when none is present. However, visual illusions can also help enhance the ability of radiologists to detect and characterize abnormalities. Indeed, radiologists have learned to exploit certain perceptual biases in diagnostic findings and as training tools. We propose that further detailed study of radiologic illusions would help clarify the mechanisms underlying radiologic performance and provide additional heuristics to improve radiologist training and reduce medical error.