CT Head Without IV Contrast CT head without IV contrast is useful in the setting of TCH because of its high sensitivity for detecting intracranial hemorrhage. Several studies have demonstrated a high negative predictive value of a noncontrast head CT performed within 6 hours of headache onset in detecting aneurysmal SAH, ranging between 99.9% and 100%. When it is performed within the first 24 hours, the sensitivity ranges between 90% and 100% [16,17]. Ten percent of patients with CVT present with SAH; associated CT abnormalities include venous infarcts, parenchymal edema, or hyperdense thrombus within the occluded sinus. Although SAH is less common in cases of ruptured AVMs, lobar hemorrhage and serpiginous structures representing dilated vasculature can be seen on a noncontrast head CT [11]. In addition, a CTA head with IV contrast may be useful in the setting of TCH when performed in conjunction with a noncontrast head CT (not as an independent initial imaging technique in isolation). There is literature supporting the usefulness of obtaining a head CTA at the same time as a head CT in a patient with TCH, especially when a patient presents with sudden onset severe headache >6 hours, because the sensitivity of head CT for SAH diminishes over time. For suspected cases of RCVS, a noncontrast head CT with special attention to the presence of convexity SAH has been shown to be useful [12] CTA Head With IV Contrast CTA head with IV contrast may be useful in the setting of TCH when performed in conjunction with a noncontrast head CT (not as an independent initial imaging technique in isolation). There is literature supporting the usefulness of obtaining a head CTA at the same time as a head CT in a patient with TCH, especially when a patient presents with sudden onset severe headache >6 hours, because the sensitivity of head CT for SAH diminishes over time.
Headache PCAs. CT Head Without IV Contrast CT head without IV contrast is useful in the setting of TCH because of its high sensitivity for detecting intracranial hemorrhage. Several studies have demonstrated a high negative predictive value of a noncontrast head CT performed within 6 hours of headache onset in detecting aneurysmal SAH, ranging between 99.9% and 100%. When it is performed within the first 24 hours, the sensitivity ranges between 90% and 100% [16,17]. Ten percent of patients with CVT present with SAH; associated CT abnormalities include venous infarcts, parenchymal edema, or hyperdense thrombus within the occluded sinus. Although SAH is less common in cases of ruptured AVMs, lobar hemorrhage and serpiginous structures representing dilated vasculature can be seen on a noncontrast head CT [11]. In addition, a CTA head with IV contrast may be useful in the setting of TCH when performed in conjunction with a noncontrast head CT (not as an independent initial imaging technique in isolation). There is literature supporting the usefulness of obtaining a head CTA at the same time as a head CT in a patient with TCH, especially when a patient presents with sudden onset severe headache >6 hours, because the sensitivity of head CT for SAH diminishes over time. For suspected cases of RCVS, a noncontrast head CT with special attention to the presence of convexity SAH has been shown to be useful [12] CTA Head With IV Contrast CTA head with IV contrast may be useful in the setting of TCH when performed in conjunction with a noncontrast head CT (not as an independent initial imaging technique in isolation). There is literature supporting the usefulness of obtaining a head CTA at the same time as a head CT in a patient with TCH, especially when a patient presents with sudden onset severe headache >6 hours, because the sensitivity of head CT for SAH diminishes over time.