The diagnosis of a nonopaque object may be difﬁcult. In selected cases, CT and ultrasound offer hope for visualization of a suspected foreign object in the superﬁcial tissues of the body (Fornage, 1986; Bodne, 1988; Gooding, 1987; Horton, 2001; Peterson, 2002; Meyer, 1982). At ultrasound, foreign objects frequently give a localized, reproducible hyperechoic appearance (figure: mesquite thorn). Needle localization techniques similar to those used for mammographic needle localization of nonpalpable breast lesions before surgical breast biopsy may occasionally aid in the surgical removal of a foreign body from the extremities or other superﬁcial soft tissues of the body.
Most foreign body injuries to the extremities or other parts of the body involve common daily activities. Motor vehicle accidents and industrial accidents account for the majority of the cases. Infrequently, foreign objects such as bullets may travel a great distance from their original site of entrance into the body (figure: shotgun injury). It is well recognized that bullets and other foreign bodies may undergo arterial or venous embolization or movement within the subarachnoid space of the head and spine. These possibilities should be considered whenever a bullet is not found on radiographs of the body part predicted to contain it based on the entrance wound and there is no obvious exit wound. Additional radiography, CT, or ﬂuoroscopy should be performed to ﬁnd the bullet (Hollerman, 1994).
Surgical items placed within or on a patient’s body are common in postoperative patients. Materials normally seen after surgery include large rubber retention sutures; large and small wire sutures; surgical drains; wound gauze packs; bandages; osteotomy bags; skin staples; hemoclips; small surgical staples; hernia mesh; and intravenous, intra-arterial, intraspinal, and intra-abdominal catheters. Other materials, such as retained abdominal sponges and needles, have been accidentally left behind after surgery (figure: retained surgical sponge). Fortunately, abnormal retained surgical materials are rare, but they may be difﬁcult to detect clinically and radiographically. This difﬁculty arises from the often nonspeciﬁc patient symptoms, poor visibility of the objects on radiographs, and the low suspicion of the radiologist and referring physician for such objects.
Although retained surgical sponges are not common, they are dreaded by surgeons and other physicians because of their potential for considerable patient morbidity. Retained sponges are also a frequent source of litigation and bad publicity for physicians. A retained surgical sponge may be discovered immediately near the end of a surgical procedure through a thorough sponge count performed by the nursing staff. If undiscovered at that point, a misplaced sponge may not be found for months to years after surgery (figure: retained surgical sponge; figure: gossypiboma).
Whenever there is the possibility of a missing sponge or other retained surgical foreign body at the end of a surgical procedure, a radiograph of the abdomen and pelvis or affected body part should be obtained to look for the retained object prior to the patient leaving the operating theater (Hunter, 2010; Walter, 2015; Porter, 2015). Every medical center should develop a policy and procedure for rapid identification of a retained surgical foreign body (figure: surgical sponges).
Gossypiboma is the term sometimes used to describe the foreign body reaction to a surgical sponge left within the body for a long period (figure: gossypiboma; figure gossypiboma on CT). The cotton matrix of the sponge forms the nidus of the foreign body reaction. Around the cotton nidus, there is surrounding ﬁbrosis, retraction, and development of a foreign body granuloma (Sturdy, 1967). The frequency of retained surgical foreign material is one per 1,000–1,500 laparotomies (Rappaport, 1990). Many patients are asymptomatic, and the retained sponge is discovered accidentally when the patient undergoes a radiologic study for some other reason.
Vertebroplasty and kyphoplasty are procedures to treat compression fractures in the thoracic and lumbar spine. Recently, their usefulness has been called into question, but they are common procedures, and many patients appear to gain considerable pain relief from them. The injected cement (usually methylmethacrylate) may on occasion extrude from the vertebral body. If it does not impinge upon the spinal cord or a nerve root, there is usually no patient harm. The material may also enter the vascular system, usually the spinal venous complex, and embolize to distant sites, such as the patient's lungs (figure: vertebroplasty cement in the lungs) (Karlsson, 2005; Taljanovic, 2006).
An interesting foreign body injury results from the deliberate or accidental injection of metallic mercury. Metallic mercury is easily recognized on radiographs. It is most commonly seen in patients who ingest it deliberately as part of a suicide attempt or who inadvertently ingest or aspirate it as a complication of long intestinal tube use. Metallic mercury at room temperature is fairly nontoxic; however, mercury compounds and metallic mercury that is warmed enough to produce signiﬁcant mercury vapor are quite toxic. Nowadays, metallic mercury is rarely seen as it is no longer used for everyday applications in thermometers or barometers, and intestinal tubes no longer contain mercury weighted bags to help with tube passage.
At one time, mercury was used as an anaerobic seal for arterial blood gas sampling during cardiac catheterization and as a seal for arterial blood gas sampling syringes and arterial pressure monitors. If the seal was broken, metallic mercury could be inadvertently injected into the arterial or venous system of the patient. Although mercury thermometers are uncommon nowadays, soft-tissue mercury deposits may be seen in patients who injure themselves by breaking a mercury thermometer.
If mercury is injected into subcutaneous tissues, it forms irregular globules and may remain in place for months to years. If it is injected into the venous system, it will embolize to the lungs where it forms small globules in the peripheral branches of the pulmonary arteries. The mercury may also pool in the right ventricle. Differentiating aspirated metallic mercury from mercury embolism to the lungs is difﬁcult on the basis of chest radiographic appearances alone. The diagnosis depends on the patient history, presence of mercury in the right ventricle or subcutaneous tissue of the arm or leg (favoring mercury embolism) or the presence of mercury in the gastrointestinal tract (favoring mercury aspiration) (Wenzel, 1980; Peterson, 1980; Spizarny, 1987). Surprisingly, metallic mercury in the bronchial tree or in the pulmonary arterial tree is usually not associated with symptoms, and it may remain undiscovered indeﬁnitely.
Foreign Body Injuries: II
Left orbital BB
Wood in calf
Barnacles in heel
49 year-old man scheduled for knee MRI. History of BB injury to left eye. Frontal and lateral facial views confirm presence of BB in left orbit, possibly in left globe. MRI was contraindicated.
22 year-old man with large piece of wood (arrows) in his calf after being assaulted with a wooden stake. From Hunter, 2003. Permission granted for use of images in this article by Radiological Society of North America (RSNA)
17 year-old boy with barnacle fragments in his heel. He had been water skiing when he came into the dock and unexpectedly encountered barnacles, pieces of which lodged into his heel. (Courtesy George Barnes, MD). From Hunter, 1994
Glass in forearm
Calcium bursal deposits
Mesquite thorn at ultrasound
39 year-old woman who punched a window receiving a forearm laceration. Frontal and lateral views of the forearm show a large glass foreign body.
Physician who had frequent steroid injections into his left knee prepatellar bursa. He developed a small tender palpable abnormality. At ultrasound two small echogenic lesions (1 and 2) were found. At surgery they were calcific deposits which were removed.
Ultrasound image of a young man who stepped on a broken mesquite tree branch. A large wooden fragment that pierced his foot was removed, but he continued to have pain and swelling over the dorsum of his foot. An echogenic focus was evident on ultrasound (cursors) which proved to be a mesquite thorn at surgery. From Hunter, 2003. Permission granted for use of images in this article by Radiological Society of North America (RSNA)
Acupuncture needles in the paraspinal subcutaneous soft tissues of 37 year-old Korean woman. The needle fragments were purposefully left in place. (Courtesy Dr. Joseph A. Alvarado). From Hunter, 1994
Elderly man with right hip pain and a draining sinus tract near the right hip. He had a right hip unipolar prosthesis placed several weeks prior in Mexico. Radiographs of the pelvis and right hip (left) show a unipolar prosthesis as well as a retained surgical sponge (arrow) in the medial aspect of the right acetabulum. The prosthesis was removed and replaced with a temporary antibiotic impregnated right hip "prosthesis" (right) made from antibiotic laden cement and held in place by press fitting and cerclage wires.
Surgical sponges used at University Medical Center, Tucson, AZ. See Hunter, 2010.
Surgical clips and clamps
Surgical needles used at University Medical Center, Tucson, AZ. SeeHunter, 2010.
Surgical blades used at University Medical Center, Tucson, AZ. SeeHunter, 2010.
Surgical clips and clamps used at University Medical Center Tucson, AZ. SeeHunter, 2010.
25 year-old woman who had undergone a Cesarean section in Mexico. She presented with abdominal pain and fever. The abdominal radiograph shows a large complex, partially lucent left flank mass with an associated linear density. At surgery there was a retained surgical sponge with surrounding area of granuloma formation, a gossypiboma. From Hunter, 2003. Permission granted for use of images in this article by Radiological Society of North America (RSNA)
Foreign Body Injuries: IV
Metallic mercury in the lungs
Elderly man with a retained surgical sponge granuloma (gossypiboma) (arrow).
Vertebroplasty cement has embolized to the patient's lungs. This was an incidental findings on a routine chest radiographic series. From Hunter, 2004a. Permission granted for use of images in this article by Radiological Society of North America (RSNA)
21 year-old man who injected himself with metallic mercury.
Metallic mercury in the lungs
Metallic mercury in the left elbow
MR artifacts from tiny metallic deposits
21 year-old man who injected himself with metallic mercury. There are mercury emboli to the lungs and metallic mercury is evident in the antecubital fossa of the left elbow. (Figures courtesy of Charles A. Rohrmann, Jr, MD. They were originally printed in Peterson, 1980).
Trick or treat candy. There are no hidden needles or razor blades. The candy and the apple (round density) where eaten with much enjoyment. From Hunter, 1994
Axial three-dimensional MR arthrogram of the left shoulder in a 40 year-old man as follow-up from prior rotator cuff repair. The arrows point to areas of susceptibility (blooming) artifact from presumed tiny metallic deposits in the shoulder from the surgery. Shoulder radiographs were normal. From Hunter, 2003. Permission granted for use of images in this article by Radiological Society of North America (RSNA)
Halloween is a fun time of year for children. Unfortunately, some individuals have taken delight in hiding needles, razor blades, and other harmful items in candy and food given to trick or treaters. Radiography of food and candy is surprisingly effective (figure: halloween candy) and can be used to identify harmful objects or to reassure parents that there is a low likelihood for a sharp object lurking in treats.