Multimodality Imaging in Patients with Secondary Hypertension: With a Focus on Appropriate Imaging Approaches Depending on the Etiologies

Abstract

Although the causes of hypertension are usually unknown, about 10% of the cases occur secondary to specific etiologies, which are often treatable. Common categories of secondary hypertension include renal parenchymal disease, renovascular stenosis, vascular and endocrinologic disorders. For diseases involving the renal parenchyma and adrenal glands, ultrasonography (US), computed tomography (CT) or magnetic resonance (MR) imaging is recommended. For renovascular stenosis and vascular disorders, Doppler US, conventional or noninvasive (CT or MR) angiography is an appropriate modality. Nuclear imaging can be useful in the differential diagnosis of endocrine causes. Radiologists should understand the role of each imaging modality and its typical findings in various causes of secondary hypertension. This article focuses on appropriate imaging approaches in accordance with the categorized etiologies leading to hypertension.

Keywords: Computed tomography; Diagnostic imaging; Magnetic resonance imaging; Nuclear imaging; Secondary hypertension; Ultrasonography.

Fig. 1. Appropriate diagnostic imaging approaches consisting of patients' symptoms, laboratory findings, and imaging modalities depending on etiologies of secondary hypertension.

BP = blood pressure, CT = computed tomography, GFR = glomerular filtration rate, MR = magnetic resonance, US = ultrasonography,é = elevated, é = decreased

Fig. 2. Glomerulonephritis in 37-year-old male with long history of hypertension and nephrotic range proteinuria.

Renal US (A) demonstrates small kidney less than 9 cm in length, with relatively higher parenchymal echogenicity (arrowheads) compared to liver (arrow). CT images (B) from arterial (upper row) and delayed phases (lower row) show irregular contour with atrophic changes in bilateral kidneys (arrowheads). Aortic dissection (arrows), possible complication of long-standing hypertension, is also noted.

Fig. 3. Autosomal dominant polycystic kidney disease in 37-year-old male with hypertension and family history of hemorrhagic stroke.

Coronal CT image (A) shows multiple cysts of variable sizes in bilateral kidneys and liver. Volume-rendered image of left internal carotid artery (B) shows tiny aneurysm (arrowhead) at level of bifurcation.

Fig. 4. Atherosclerotic renovascular stenosis in 76-year-old female with hypertension and recent onset azotemia.

Coronal CT image with maximum intensity projection (A) shows diffuse atherosclerotic change in aorta and its branches, with focal narrowing (arrow) of proximal segment of left renal artery. Conventional angiography (B) redemonstrated severe stenosis of left renal artery (arrowhead). Lesion was targeted by transluminal angioplasty (arrow), with resultant restoration of luminal diameter. Although blood pressure did not reduce immediately, azotemia was improved.

Fig. 5. Fibromuscular dysplasia in 20-year-old male with hypertension.

Maximum intensity projection image (A) shows focal narrowing with luminal irregularities in middle segment of right renal artery (arrows). Doppler US (B) reveals tardus-et-parvus waveform with low resistive index of right kidney (labeled as R) compared to left kidney (labeled as L). Aortography and selective right renal arteriography (C) confirmed focal stenosis with luminal irregularities (arrows) in right renal artery causing ipsilateral perfusion delay (arrowheads).

Fig. 6. Coarctation of aorta in 46-year-old female with hypertension and dyspnea on exertion.

Plain radiograph of chest (A) shows left ventricular hypertrophy, small contour of aortic arch (arrowheads), and mild notching of a few ribs (arrows). Volume-rendered CT image (B) reveals postductal type of aortic coarctation (arrowheads), with well-developed collaterals via internal mammary and intercostal arteries (arrows). Reformatted image of valve (C) shows bicuspid aortic valve (arrows), one of well-known anomalies associated with coarctation of aorta. Patient underwent corrective surgery (Bentall operation) with subsequent normalization of blood pressure.

Fig. 7. Mid-aortic dysplastic syndrome in 62-year-old female with hypertension and intermittent claudication.

Serial axial CT image (A) shows segmental luminal narrowing of abdominal aorta with calcified vascular wall (arrowheads). Volume-rendered image (B) demonstrates aortic stenosis involving ostia of bilateral renal arteries (arrows). Maximum intensity projection in CT angiography (C) shows segmental narrowing of infrarenal abdominal aorta with concentric calcification (arrowheads), probably due to sequelae of Takayasu aortitis. Note resultant collaterals (arrows) between bilateral intercostal, circumflex iliac, and epigastric arteries.

Fig. 8. Primary aldosteronism in 68-year-old male with uncontrolled hypertension, low level of plasma renin activity (0.2 ng/mL/hr) and elevated aldosterone level (47 ng/dL).

Incidentally detected right adrenal mass (arrowheads) (A), with attenuation coefficients of 8, 43, and 21 Hounsfield units at pre-contrast (upper column), portal venous (middle column), and delayed phases (lower column), respectively, making absolute percentage washout of 65% and relative percentage washout of 55%, consistent with adenoma. Right adrenal venous sampling (arrows) (B) confirmed high aldosterone level (13680 ng/dL). Subsequent right adrenalectomy yielded lesion that was confirmed to be adenoma.

Fig. 9. Cushing's syndrome in 65-year-old female with hypertension, diabetes mellitus, and generalized weakness and markedly elevated adrenocorticotropic hormone (1260 pg/mL).

Axial CT scan (A) shows bilateral adrenal masses (arrowheads) with strong cortical enhancement. Whole-body PET (B) shows hypermetabolic adrenal masses (arrows), corresponding to CT. Lesions were surgically resected and were confirmed to be bilateral adrenal cortical hyperplasia.

Fig. 10. Pheochromocytoma in 49-year-old male with hypertension, headache, and chest discomfort.

Coronal CT image (A) shows heterogeneously enhancing right adrenal mass with lobulated contour (arrowheads). Nuclear scintigraphy (B) shows high uptake of metaiodobenzylguanidine 28 hours after injection (arrow).

Fig. 11. Thyroid dysfunction in 79-year-old female with hypertension, depressed thyroid-stimulating hormone (< 0.01 µIU/mL), elevated T3 (4.4 ng/mL), and free T4 (> 5.54 ng/dL).

Color Doppler US (A) demonstrates diffusely enlarged left thyroid (arrowheads, right not shown) with heterogeneous parenchymal echogenicity, with so-called “thyroid inferno,” appearing as markedly increased vascularity. Coronal image of hybrid single positron emission CT (B) and maximum intensity projection (C) show increased uptake of 99mTc within both thyroid glands (arrows in B and C). Patient was diagnosed with Graves' disease and was started on methimazole.

Fig. 12. Hyperparathyroidism in 47-year-old female with hypertension and generalized weakness.

Plain radiographs show multiple well-defined osteolytic lesions within femur (arrow) (A), presumably brown tumors, and subperiosteal bone resorption of phalanges of hand (B). Neck CT (C) shows inhomogeneous mass (arrowheads) located inferiorly to right thyroid. US (D) revealed hypoechoic mass in right lower parathyroid (arrowheads) containing focal calcification. Sestamibi scan (E) obtained two hours after radiotracer administration shows high uptake of Tc-99m in right lower neck (arrow). Lesion was later surgically confirmed to be parathyroid adenoma.