The ultrasound picture, or sonogram, often serves as a first portrait, holding immense personal meaning. This printout is a tangible representation of a moment in time, marking the initial visual connection with a developing fetus or providing diagnostic information. Understanding the physical properties of these images helps manage expectations for display and long-term care. This article clarifies the typical physical dimensions and formats of the printouts provided by medical facilities.
Standard Dimensions of Sonogram Prints
The standard size of a sonogram print is dictated by the specialized equipment used in medical settings. Most common printouts are black-and-white images produced on thermal paper rolls, and the standardized width of these rolls leads to a consistent size for the final print. These thermal printouts frequently align with the A6 paper width standard, typically 110 millimeters (mm) wide (approximately 4.3 inches). Another common roll width is 84 mm (3.3 inches), corresponding to an A7 standard.
Since the prints are on a continuous roll, their length can vary, but the image itself is usually cropped to a square or slightly rectangular format within this fixed width. This standardization results from the widespread use of specific video printers manufactured for medical imaging devices.
Why Ultrasound Images Are Printed on Thermal Paper
The distinct, slightly glossy feel and monochrome appearance of the standard printout result directly from the printing technology used. Ultrasound machines utilize thermal printers, which are highly efficient for a medical environment. These printers rely on heat to chemically react with a specialized coating on the paper, eliminating the need for ink cartridges or toner.
The paper is a multi-layered synthetic material with a heat-sensitive layer that changes color when subjected to the thermal print head. This inkless process offers speed and requires minimal maintenance, making it cost-effective and practical for high-volume clinical use. Thermal printers are also compact and low power, allowing them to be built directly into portable ultrasound units.
Variations in Size and Format
While the standard black-and-white thermal print is the most common, alternative formats exist, especially for more advanced imaging. Three-dimensional (3D) and four-dimensional (4D) ultrasounds capture volumetric data, which is rendered by software to create a surface view. To adequately display the enhanced detail and depth, clinics may opt for larger, non-thermal prints.
These higher-resolution images are often printed on standard photographic paper, resulting in sizes like 5×7 inches or 8×10 inches. Photographic paper offers better color reproduction and longevity than thermal paper. The physical print is also increasingly supplemented or replaced by digital files, such as those saved to a USB drive or sent via email.
Display and Preservation Considerations
The unique material of the thermal paper requires specific care to prevent image degradation over time. The heat-sensitive coating that forms the image is vulnerable to heat, light, and friction. Exposure to direct sunlight, high temperatures, or even the heat from lamination can cause the image to fade or turn completely black.
For long-term preservation, the original thermal print should be stored in a cool, dry, and dark environment, ideally within an acid-free sleeve or album. The most reliable method for preserving the image is to digitize it immediately using a high-resolution scanner (300 to 600 DPI or higher). Once digitized, the image can be printed on durable photo paper in any desired size, addressing the challenges of framing the original non-standard dimensions.