Assessment of image quality and dose in contrast-enhanced head and neck CT angiography of New Zealand rabbit.

BACKGROUND: Although computed tomography (CT) is a powerful diagnostic imaging modality for diagnosing vascular diseases, it is some what risky to human health due to the high radiation dosage. Thus, CT vendors have developed low dose computed tomography (LDCT) aiming to solve this problem. Nowadays, LDCT has gradually become a main stream of CT examination. OBJECTIVE: This study aimed to assess the feasibility of LDCTAin an animal model and compare the imaging features and doses in two clinical scanners. METHODS: Twenty-two New Zealand rabbit head and neck CTA images pre- and post-contrast agent injection were performed using256-sliceand 64-slice CT scanners. The tube voltages used in the 256-slice and the 64-slice CTA were 70 kVp and 80 kVp, respectively. Quantitative images indices and radiation doses obtained from CTA in these two scanners were compared. RESULTS: More neck arterial vessels could be visualized in multi-planar reconstruction (MPR) CTA on the 256-slice CT scanner than on the 64-slice CT scanner. After contrast agent injection, all observed neck arterial vessels had higher CT numbers in 256-slice CTA than in 64-slice CTA. There was no significant difference in contrast-to-noise (CNR) of CTA images between these two scanners. CT dose index (CTDI) and dose length product (DLP) for the 256-slice CTA were lower than those for the 64-slice CTA. CONCLUSIONS: Low dose CTA of rabbits with 70 or 80 kVp is feasible in a 256-slice or a 64-slice CT scanner. The radiation dose from the 256-slice CTA was much lower than that from the 64-slice CTA with comparable SNR and CNR. The technique can be further applied in longitudinal monitoring of an animal stroke model in the future.

Camera-based assessment of arterial stiffness and wave reflection parameters from neck micro-motion.

The feasibility of a camera-based extraction of carotid distension waveforms offers the prospect of a user-friendly alternative to laser Doppler velocimetry (LDV) or accelerometry-based systems. Upon supplementary calibration of vessel wall displacement to arterial pressure, our system may also be an appealing alternative to applanation tonometry for extracting cardiac-related features from the central pulse pressure waveform. OBJECTIVE: This paper describes the application of camera-based micro-motion imaging to extract health-related features from the contour of the carotid displacement waveform. APPROACH: We build on the assumption that the cardiac-related frequency components of the skin motion (sMOT) waveform, as acquired at the vicinity of the carotid artery under uneven illumination, receive a dominant contribution from the carotid wall displacement. We propose a two-step approach at which sMOT signals are queried based on the local amplitude of remote-photoplethysmography sensors spanning the neck's skin and then ensemble-averaged for cardiovascular health assessment. MAIN RESULTS: The feasibility of the system is demonstrated for assessing stiffness index, augmentation pressure, augmentation index and reflection magnitude on a dataset comprising 28 participants (ages 23 to 62 yrs; 22 males). SIGNIFICANCE: Although presented here as a standalone system, micro-motion imaging can be an auxiliary technique for improving sensor placement and signal quality of tonometric or LDV technologies.

Noncontact diffuse optical assessment of blood flow changes in head and neck free tissue transfer flaps.

Knowledge of tissue blood flow (BF) changes after free tissue transfer may enable surgeons to predict the failure of flap thrombosis at an early stage. This study used our recently developed noncontact diffuse correlation spectroscopy to monitor dynamic BF changes in free flaps without getting in contact with the targeted tissue. Eight free flaps were elevated in patients with head and neck cancer; one of the flaps failed. Multiple BF measurements probing the transferred tissue were performed during and post the surgical operation. Postoperative BF values were normalized to the intraoperative baselines (assigning "1") for the calculation of relative BF change (rBF). The rBF changes over the seven successful flaps were 1.89 ± 0.15, 2.26 ± 0.13, and 2.43 ± 0.13 (mean ± standard error), respectively, on postoperative days 2, 4, and 7. These postoperative values were significantly higher than the intraoperative baseline values (p<0.001), indicating a gradual recovery of flap vascularity after the tissue transfer. By contrast, rBF changes observed from the unsuccessful flaps were 1.14 and 1.34, respectively, on postoperative days 2 and 4, indicating less flow recovery. Measurement of BF recovery after flap anastomosis holds the potential to act early to salvage ischemic flaps.

Assessment of free microvascular flap perfusion by intraoperative fluorescence angiography in craniomaxillofacial surgery.

Microsurgical tissue transfer represents a standard technique for reconstruction in craniomaxillofacial surgery. The transferred tissue is anastomosed to vessels of varying diameters and different physiological conditions. The aim of this study was to evaluate the blood flow in free flaps at their origin and compare this with the flow after reperfusion. In 24 patients undergoing microsurgical procedures (13 radial forearm free flaps (RFFF) and 11 parascapular/scapular free flaps (PSFF)), blood flow was evaluated by intraoperative fluorescence angiography after flap raising and again after reperfusion in the neck area (Flow800, Carl Zeiss AG, Oberkochen, Germany). Flow is expressed by the blood flow index (BFI), maximum intensity (MaxInt) and half-time to MaxInt (t1/2) and was measured in the flap pedicle itself, as well as in the supplying vessels. Following anastomosis of the free flaps in the head and neck area, both the arterial and the venous BFI and MaxInt significantly increased, whereas t1/2 decreased significantly. There was no significant difference in the perfusion parameters between RFFF and PSFF. Intraoperative fluorescence angiography is a reliable method for assessing the perfusion of free microvascular flaps. In the head and neck area, free flaps undergo a significant increase in perfusion but show no differences between varying flap types.

Review of multidetector computed tomography angiography as a screening modality in the assessment of blunt vascular neck injuries.

Blunt vascular neck injuries (BVNI), previously thought to be rare, have demonstrated increasing incidence rates in recent literature and are associated with significant mortality and morbidity. A radiologist needs to efficiently recognize these injuries on preliminary screening to enable initiation of early management. When initiation of accurate management is started promptly, decreased rates of postinjury complications, for example, stroke, have been demonstrated. This article reviews the incidence, pathophysiology, and rationale for screening for these BVNI injuries. The utility of computed tomography angiography (CTA) as the potential new criterion standard as the screening and follow-up imaging modality for BVNI will be discussed. The application of new multidetector CTA techniques available, such as dual-energy CT and iterative reconstruction, are also reviewed. In addition, the characteristic imaging findings on CTA and the associated Denver Grading scale for BVNI will be reviewed to allow readers to become familiar with the injury patterns and to understand the prognostic and clinical implications, respectively. Examples of the spectrum of injuries, potential injury mimics, and different artifacts on multidetector CTA are shown to help familiarize readers and allow them to successfully and confidently recognize a true BVNI.

Volumetric assessment of results of treatment of vascular malformations of the head and neck regions treated with a minimally invasive surgical technique after embolization procedure.

Treatment of large soft tissue vascular lesions, one of the greatest challenges facing plastic surgeons, is patient specific in almost all cases, and preoperative angiographic evaluation and embolization of these lesions are standards of care. The aim of this study was to evaluate the usefulness of 3-dimensional demonstration and volumetric assessment of soft tissue vascular lesions both in the treatment of these lesions with curettage and in the participation of the patients to the decision-making process of the disease. Five patients with vascular malformation of the head and neck regions were included to this prospective trial. All patients were evaluated with preoperative angiography, and selective embolizations of the soft tissue vascular lesions were done in the same session by the same interventional radiologists. The amount of embolic agent injected was determined according to the size and vascularization of the lesions. Surgery was done by curettage of the embolized lesions 7 to 10 days after the embolization procedure. The raw data obtained from preoperative and postoperative high-resolution computed tomographic scans of the patients were processed with a Mimics 9.22 Software (Materialise's Interactive Medical Image Control System, Leuven, Belgium). Volume and surface area of the injected embolic agent were assessed. Statistical analysis was performed using the software package SPSS 10.0 for Windows (SPSS Inc, Chicago, IL). Wilcoxon signed rank test was used to compare the measurements of the volume and the surface area of injected sclerosing agent preoperatively and postoperatively. There were no complications related to either the preoperative angiography or embolization procedure. All the patients emphasized (assessed) that the 3-dimensional demonstration of the lesions and their relation with other anatomic structures helped them to understand the extent of their pathology and aim of the proposed treatment. The difference between the volumetric measurements before and after the treatment was found statistically significant. Treatment of large soft tissue vascular lesions with curettage after embolization has acceptable cosmetic results. Although it is not possible to remove all of the sclerosing agent from its injection site with this technique, a significant amount of it can be removed, and the 3-dimensional vascular architecture of the lesion is disturbed. Reactive chronic inflammation against the remaining sclerosing agent and the intralesional scarring caused by curettage lead to further improvement. Using 3-dimensional imaging modalities helps patients and/or their relatives to understand their disease and participate in the decision-making process.

Assessment of cervical venous blood flow and the craniocervical venus valve using ultrasound sonography.

Severe congestion with petechiae and/or small hemorrhages over a wide area consisting of the subcutaneous and mucous level of the head and neck is observed in most cases of strangulation and positional asphyxial death. Congestion present above the strangulation mark is accepted as a vital reaction. Although the congestion results from a disturbance of cervical venous flow, only a few reports concerning a relationship between venous flow and posture were found in the literature. We assessed the physiological situation of cervical venous return and movement of the craniocervical venous valve for many types of valve with respect to posture using color-duplex ultrasound sonography (US). We measured the Doppler wave of cervical veins consisting of internal jugular vein (IJV), external jugular vein (EJV) and vertebral vein (VV) and the motion of IJV valves in three positions on a seat which could be manually moved through +90 degrees to -90. The diameter of IJVs and EJVs were thicker in a head-down position, moderate in a supine position and flat in a sitting position. The diameter of VVs was thick in a sitting position, moderate in supine position and unclear in an upside-down position because of difficulty in scanning owing to very slow velocity and deep lying position. The velocities were high in a sitting position, but very slow and intermittent in an upside-down position. The EJV which is markedly congested in some cardiac tamponade cases and drains mainly the facial superficial region is very important in legal medicine but has not often observed in previous reports. We confirmed that cervical venous return (IJV, EJV, VV) changes its route according to the posture. The motion of IJV valves was very complicated and varied in three positions, even after the Doppler wave and the motion of valve became stable. Asphyxia and strangulation should be studied taking the complex venous structure into consideration. We could not find any consistent explanation for venous valve motion and further studies on the valves are necessary to understand the venous reflux in some diseases in legal medicine.

Assessment of origin characteristics of the front branches of the external carotid artery.

The neck region has a great vital value; its variations and known micrometric values are accepted as important orientation points during intervention. Micrometric values of the front branches of the external carotid artery and their relations to the surrounding structures and metric data pertaining to origin locations of the superior thyroid (STA), lingual (LA), and facial (FA) arteries were evaluated in 40 samples. As regards the evaluation of the branching types of the external carotid artery, the cases where the STA, LA, and FA originated as separate branches were 90%, linguofacial trunk cases were 7.5%, and thyrolingual trunk cases were 2.5%. The diameters of the STA, LA, and FA at their origins were observed to be 3.53 +/- 1.17, 3.06 +/- 0.65, and 3.35 +/- 0.68 mm, respectively. The distances from the origin of the STA to the carotid bifurcation of 3.29 +/- 4.27 mm, origin of the STA to that of the LA of 10.45 +/- 5.16 mm, and origin of the STA to that of the FA of 18.20 +/- 8.81 mm were found. The current findings may have serious implications for radiologic examinations, exploration of the neck, thyroid and parathyroid surgery, tracheotomy, and surgery of the larynx, pharynx, upper esophagus, pterygopalatine, and infratemporal fossa.

High resolution 3T MRI for the assessment of cervical and superficial cranial arteries in giant cell arteritis.

A new high-resolution MR protocol for the combined assessment of neurovascular arterial anatomy and subsequent evaluation of inflammatory disease in cranial vessels walls has been investigated. First-pass contrast-enhanced MR angiography (CE-MRA) in combination with parallel imaging at high field permits the depiction of the neurovascular geometry with large coverage, including the aortic arch, supraaortic vessels, and almost the entire head, with high, submillimeter detail. Utilizing the remaining contrast agent, postcontrast T(1)-weighted turbo spin-echo (TSE) imaging was used to generate late enhancement images of the vessel walls to assess the morphology and potential inflammatory changes in cranial arteries with high in-plane (195 x 260 microm(2)) spatial resolution. As a result, a combined analysis of neurovascular arterial anatomy as well as cranial vessel wall inflammations could be achieved in less than 45 minutes in all studies. The feasibility and clinical value for the diagnosis of rheumatologic diseases and simultaneous arteriosclerotic involvement was demonstrated in seven patients with suspected giant cell arteritis (GCA). Excellent CE-MRA image quality could be achieved and even vascular geometry of small superficial cranial arteries could be successfully visualized using single dose (0.1 mmol/kg) contrast agent administration and a dedicated phased-array head and neck coil at 3T.

Impact of MDCT angiography on the use of catheter angiography for the assessment of cervical arterial injury after blunt or penetrating trauma.

OBJECTIVE: The objective of our study was to assess the impact of the increasing use of MDCT angiography in the setting of blunt and penetrating neck trauma on the use of digital subtraction angiography (DSA) at our institution, a level 1 trauma center. MATERIALS AND METHODS: From January 2001 to December 2003, 57 patients were referred for CT angiography or DSA of the neck after blunt or penetrating neck trauma. All CT angiograms were acquired with a 4-MDCT scanner. The patients were divided into three groups on the basis of consecutive 12-month periods (2001, 2002, and 2003), and the initial imaging technique was recorded. The results of CT and digital subtraction angiograms were compared with operative findings and with clinical course, when available. RESULTS: In 2001, 12 patients were referred for imaging: nine patients were evaluated initially with DSA and three patients were evaluated with CT angiography and subsequently with DSA. In 2002 and 2003, 11 and 34 patients, respectively, underwent CT angiography as the initial imaging examination. During these 2 years, no patient underwent DSA as the initial diagnostic test, but five patients underwent DSA after CT angiography for the following indications: evaluation of nondiagnostic CT angiograms (n = 1), confirmation of findings when requested by the clinical service (n = 2), and catheter-guided therapy (n = 2). CONCLUSION: CT angiography has essentially replaced DSA as the study of choice for the initial evaluation of the neck vessels in the setting of blunt or penetrating trauma at our institution. CT angiography is adequate for the initial evaluation, allows appropriate triage of patients to conventional angiography or surgery for appropriate treatment, and can guide conservative management when appropriate.

Integrated head-thoracic vascular MRI at 3 T: assessment of cranial, cervical and thoracic involvement of giant cell arteritis.

Recently, high-resolution contrast-enhanced MRI has proven to be feasible for noninvasive diagnosis of giant cell arteritis in the cranium. In such examinations, thickening of the vessel wall and/or increased contrast enhancement demonstrate mural inflammation. Typically, the superficial cranial arteries with predominance of the superficial temporal artery are affected by the disease. However, giant cell arteritis can also involve other parts of the vascular system and an examination with extended coverage, including head, neck, and thorax would be advantageous. In this study, a novel approach for integrated head-thoracic vascular MRI at 3 T is presented. Combining first-pass imaging of a single-dose contrast agent with post-contrast imaging permits the assessment of both thoracic aortic geometry and wall, in addition to high-resolution head imaging needed for the analysis of the small superficial cranial arteries. Results from a patient feasibility study are presented and confirm that the protocol can successfully be completed in less than 40 min.

Comparing microvascular outcomes at a large integrated health maintenance organization with flagship centers in the United States.

OBJECTIVE: To determine if patients undergoing microvascular reconstructive head and neck surgery (MRHNS) at a large integrated health maintenance organization can expect outcomes similar to some of the best or flagship centers in the United States. DESIGN: Outcomes (flap loss, mortality, length of stay), eligibility (recent consecutive US center experience), high-experience (100 cases), high-volume (26 cases per year), and flagship criteria were prospectively defined. A systematic MEDLINE search identified 17 eligible reports. Independent, blinded medical reviewers identified 5 centers (29%) as flagship centers. PATIENTS: The first 116 consecutive patients (average, 39 cases per year) who underwent MRHNS on this service. RESULTS: All 5 flagship centers are major academic health centers ranked in the top 18 "best head and neck hospitals" in the United States. Flap loss (1.7% vs 4.4% for flagship centers; range, 0.9%-8.8%) and mortality (2.6% vs 2.8% for flagship centers; range, 0.5%-6.3%) rates were not significantly different. Although lengths of stay in flagship centers were similar to each other and the literature (mean, 21.4 days; range, 20.1-22.5 days), our length of stay was significantly shorter (8.8 days, P<.001). CONCLUSION: For high-experience and high-volume centers, patients undergoing MRHNS at a large integrated health maintenance organization can expect morbidity and mortality outcomes similar to flagship centers in the United States, with shorter hospitalizations.

Colour Doppler ultrasound in preoperative assessment of the neck vessels in patients with tumours of the oral cavity and the neck region.

BACKGROUND: The aim of the study was not only to establish the applicability of color Doppler ultrasound of the neck vessels in patients with tumors of the oral cavity and the neck region but also to check whether the coexistence of sclerotic changes in the carotid arteries is essential in determination of the sequence of surgical procedure. MATERIAL/METHODS: Color Doppler ultrasound was performed on 110 patients, aged 15 -71 years with tumors of the oral cavity and the neck. The localization, size, echogenicity, as well as the tumor relationship to the surrounding structures and big vessels of the neck region was analyzed. RESULTS: Compression of the veins was observed in 27 cases, and of the arteries only in 20 cases. Infiltration of the jugular vein was observed in 8 patients, whereas infiltration of the carotid artery were seen only in 6 patients. Severe internal carotid artery stenosis, due to arteriosclerosis, was observed in 10 patients. Three persons were suggested to be operated on, first due to carotid artery stenosis, later on, due to the oral cavity tumor. CONCLUSIONS: It was found that color Doppler ultrasound is useful in deciding upon the method of treatment, while the examination of the neck vessels is helpful in establishing the sequence of surgical procedures in patients with tumors and coexisting arteriosclerosis.

Early experience with computed tomographic angiography in microsurgical reconstruction.

Preoperative angiography is frequently used in the planning of microsurgical reconstruction. However, several potentially devastating complications can result from angiography, including arterial occlusion and pseudoaneurysm. Computed tomographic angiography is a relatively new technique that can provide detailed information about vascular anatomy as well as soft and bony tissue without the risks of traditional angiography. In addition, three-dimensional image reconstruction uniquely demonstrates anatomical relationships among blood vessels, bones, and soft tissue. Fourteen computed tomographic angiograms were obtained in 10 patients undergoing microsurgical reconstruction of the head and neck, lower extremity, or upper extremity. The average patient age was 46.9 years (range, 22 to 67 years). Charges related to the computed tomographic procedure were compared with those of conventional preoperative imaging for microsurgical repair. At our institution, the average computed tomographic angiogram charge was 1140 US dollars, whereas the average charge for traditional arteriography was 3900 US dollars. When compared with intraoperative evaluation, computed tomographic angiograms demonstrated clinically relevant surgical anatomy. No complications were noted for the radiographic procedure or after free flap reconstruction. Computed tomographic angiography provides high-resolution, three-dimensional arterial, venous, and soft-tissue imaging without the risks of traditional angiogram and at a lower cost.

Non-invasive assessment of neck-vessel pathology.

Clinical trials (NASCET, ECTS) have shown that carotid endarterectomy is protective against stroke in patients with symptomatic severe carotid stenosis. To decrease costs and risks, new diagnostic tools have been developed, such as duplex ultrasound (DUS), magnetic resonance angiography (MRA), and more recently computed tomography angiography (CTA). CTA and MRA provide excellent 3D angiography images of the extracranial vessels, using a volume-rendering technique. Digitally subtracted MRA (DSA-MRA) obtained with high-speed acquisitions during gadolinium injection has also recently become available. These techniques are changing the role of non-invasive assessment of carotid stenosis. Although it is probably too early to assess a definite diagnostic algorithm, the use of DSA as a pre-surgical tool for defining carotid stenosis is rapidly decreasing.

Limited value of preoperative cervical vascular imaging in patients with velocardiofacial syndrome.

The purpose of this two-part study was to evaluate the safety of surgical management of speech production disorders in patients with velocardiofacial syndrome without preoperative cervical vascular imaging studies. Anomalous internal carotid arteries have been shown to be a frequent feature of velocardiofacial syndrome. These vessels pose a potential risk for hemorrhage during velopharyngeal narrowing procedures. Magnetic resonance angiography, and other forms of cervical vascular imaging studies such as computerized tomography, have been advocated as aids to surgery by defining the preoperative vascular anatomy. However, it remains unclear whether these studies alter either the conduct or outcome of operations on the velopharynx. In the first part of this study, we reviewed the charts and videonasendoscopic evaluations of 39 consecutive patients with confirmed or suspected velocardiofacial syndrome who underwent sphincter pharyngoplasty or pharyngeal flap from 1978 to 1996. The charts were reviewed to determine (1) the frequency of identification of abnormal pharyngeal pulsations; (2) whether such pulsations affected the conduct of the operative procedure; and (3) whether the presence of pulsations affected surgical morbidity and/or surgical outcome. None of the patients underwent any type of cervical vascular imaging study. In the second part of this study, we surveyed plastic surgeons with numerous years of experience participating on cleft-craniofacial teams, to ascertain practice patterns relating to the management of patients with velocardiofacial syndrome. The questions related specifically to the surgeons' behavior in relation to angiography and their awareness of any cases of surgical morbidity related to the cervical vascular system in patients with velocardiofacial syndrome. We were interested in discerning both how commonly this situation arises clinically and the distribution of the various types of operative procedures in common use. Of our 39 patients, 10 patients (26 percent) had detectable pulsations on preoperative nasendoscopy. Of these, five patients underwent sphincter pharyngoplasty and five underwent pharyngeal flap procedures. Preoperative instrumental and intraoperative clinical assessment of pulsatile vessels allowed velopharyngeal reconstruction in all patients without surgical morbidity. Results of the questionnaire indicated that most cleft surgeons do not routinely order cervical vascular imaging studies for all of their patients with velocardiofacial syndrome. About half of the respondents indicated that their operative approach was influenced by information obtained from angiographic studies. None of the surgeons queried were aware of any cases of surgical morbidity related to the cervical vascular system in patients with velocardiofacial syndrome. Nearly 50 percent of surgeons use pharyngeal flap procedures most frequently, whereas 22 percent of surgeons use sphincter pharyngoplasty most frequently. Results of this study support the safety of sphincter pharyngoplasty or pharyngeal flap procedures in patients with velocardiofacial syndrome without preparatory angiography. These procedures can be performed safely, even in patients having aberrant velopharyngeal pulsations. Given the market cost of magnetic resonance angiography ($1600), one must question the cost-efficacy of magnetic resonance angiography for routine use in the velocardiofacial syndrome population.

Penetrating neck trauma: sensitivity of clinical examination and cost-effectiveness of angiography.

PURPOSE: To evaluate penetrating neck trauma for (a) sensitivity of the clinical examination as an indicator of clinically significant vascular injury, and (b) cost-effectiveness of performing screening diagnostic angiography. METHODS: The medical records of all patients with penetrating neck trauma presenting at our institution over 4 years were retrospectively reviewed. Injuries were classified into one of three anatomic zones and classified into four mutually exclusive groups based on the extent of vascular injury; (a) no vascular injury; (b) minor vascular abnormality; (c) major vascular abnormality without a change in clinical management; or (d) any injury requiring a change in clinical management. Cost data were also obtained for each patient's hospitalization. RESULTS: There were 111 patients with penetrating neck trauma. No statistically significant difference between the sensitivities of the clinical examination or angiography for the detection of vascular injury were detected. Of the 48 patients who had vascular injuries, 45 had an abnormal clinical findings (93.7% sensitivity). None of the remaining 3 patients with vascular injury and normal clinical findings would have had their treatment altered by the results of angiography. The calculated cost of using angiography as a screening tool for vascular injury in patients with normal clinical findings was approximately $3.08 million per central nervous system event prevented. CONCLUSION: Our study suggests that in patients with zone II penetrating neck injuries the clinical examination is sufficient to detect significant vascular lesions and that screening angiography may not be indicated. Because our sample size was relatively small and the mean follow-up only 13.3 days, further investigation is needed to demonstrate definitively the lack of usefulness of screening angiography.

Mandatory vs selective exploration for penetrating neck trauma. A prospective assessment.

To determine the optimal management of patients with penetrating wounds to zone II of the neck, we performed a prospective evaluation of 120 consecutive patients with such injuries, correlating the results of clinical and diagnostic examinations with operative findings. Seven patients presenting with life-threatening hemorrhage from the neck wound were operated on immediately; the remaining 113 patients underwent arteriography, laryngotracheoscopy, esophagoscopy, and esophagography, followed by neck exploration. Forty-eight major injuries were identified in 35 neck explorations. Five patients were identified with clinical and diagnostic findings that were considered normal preoperatively; however, at operation six major injuries were found in these patients. This study indicates that potentially lethal injuries to major vascular and visceral structures in the neck may go undetected if selective exploration criteria are used in the decision to explore penetrating wounds to zone II of the neck.